33 CFR 115.70 - Advance approval of bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

33 CFR 115.30 - Sufficiency of State authority for bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... for bridges. 115.30 Section 115.30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.30 Sufficiency of State authority for bridges. An opinion of the attorney general of the State as to the sufficiency of State...

33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

Code of Federal Regulations, 2012 CFR

2012-07-01

... communication lines over reservoirs. 222.3 Section 222.3 Navigation and Navigable Waters CORPS OF ENGINEERS... Works responsibilities. (c) References. (1) ER 1180-1-1 (Section 73). (2) National Electrical Safety... including temperature, loading and length of spans as outlined in the National Electrical Safety Code. (3...

33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

Code of Federal Regulations, 2014 CFR

2014-07-01

... communication lines over reservoirs. 222.3 Section 222.3 Navigation and Navigable Waters CORPS OF ENGINEERS... Works responsibilities. (c) References. (1) ER 1180-1-1 (Section 73). (2) National Electrical Safety... including temperature, loading and length of spans as outlined in the National Electrical Safety Code. (3...

33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

Code of Federal Regulations, 2013 CFR

2013-07-01

... communication lines over reservoirs. 222.3 Section 222.3 Navigation and Navigable Waters CORPS OF ENGINEERS... Works responsibilities. (c) References. (1) ER 1180-1-1 (Section 73). (2) National Electrical Safety... including temperature, loading and length of spans as outlined in the National Electrical Safety Code. (3...

33 CFR 115.30 - Sufficiency of State authority for bridges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... for bridges. 115.30 Section 115.30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.30 Sufficiency of State authority for bridges. An opinion of the attorney general of the State as to the sufficiency of State...

33 CFR 115.70 - Advance approval of bridges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

76 FR 72238 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-22

... Non-Federal Navigation Facilities AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice... navigation which are purchased, installed, operated, and maintained by an entity other than the FAA and are... private and public other than FAA, to purchase, install, operate, and maintain electronic navaids for use...

UAS Cross Platform JTA

DTIC Science & Technology

2014-07-18

1.16 Verify system align and degradations to determine impact to mission. 17 1.17 Ensure clearance of line personnel, ground equipment, and other...as needed during phases of flight. 99 7.12 Manage data security and data links during communications. 100 7.13 Obtain IFR clearance over radio...example, heading or airspeed) to return aircraft to intended course. 116 8.10 Perform navigation under instrument flight rules ( IFR ). 117 8.11

33 CFR 117.47 - Clearance gauges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drawbridges across navigable waters of the United States discharging into the Atlantic Ocean south of Delaware Bay (including the Lewes and Rehoboth Canal, DE) or into the Gulf of Mexico (including coastal...

33 CFR 117.47 - Clearance gauges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... drawbridges across navigable waters of the United States discharging into the Atlantic Ocean south of Delaware Bay (including the Lewes and Rehoboth Canal, DE) or into the Gulf of Mexico (including coastal...

33 CFR 117.47 - Clearance gauges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... drawbridges across navigable waters of the United States discharging into the Atlantic Ocean south of Delaware Bay (including the Lewes and Rehoboth Canal, DE) or into the Gulf of Mexico (including coastal...

33 CFR 117.47 - Clearance gauges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... drawbridges across navigable waters of the United States discharging into the Atlantic Ocean south of Delaware Bay (including the Lewes and Rehoboth Canal, DE) or into the Gulf of Mexico (including coastal...

78 FR 48609 - Drawbridge Operation Regulation; Delaware River, NJ; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-09

... townships of Tacony, PA and Palmyra, NJ. The deviation cited incorrect vertical clearances in the navigable... the Delaware River, mile 107.2, between the townships of Tacony, PA and Palmyra, NJ. The deviation...

78 FR 35757 - Drawbridge Operation Regulations; Connecticut River, Westport, CT

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-14

... 82 Bridge has a vertical clearance of 22 feet at mean high water and 25 feet at mean low water in the... River supports both commercial and recreational navigation of various sizes. In accordance with 33 CFR...

23 CFR 650.809 - Movable span bridges.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Movable span bridges. 650.809 Section 650.809 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge...

23 CFR 650.809 - Movable span bridges.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Movable span bridges. 650.809 Section 650.809 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge...

77 FR 76291 - Agency Information Collection Activities: Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-27

... collection titled, ``Clearance for Consumer Attitudes, Understanding, and Behaviors with Respect to Financial... Consumer Attitudes, Understanding, and Behaviors with Respect to Financial Services and Products. OMB... consumer attitudes, beliefs, and behaviors as they navigate financial decisions. It will help the CFPB...

33 CFR 118.160 - Vertical clearance gauges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... distance between “low steel” of the bridge channel span (in the closed to navigation position for... approaching vessels and extend to a reasonable height above high water so as to be meaningful to the viewer... protection structure and made of a durable material of sufficient strength to provide resistance to weather...

33 CFR 118.160 - Vertical clearance gauges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... distance between “low steel” of the bridge channel span (in the closed to navigation position for... approaching vessels and extend to a reasonable height above high water so as to be meaningful to the viewer... protection structure and made of a durable material of sufficient strength to provide resistance to weather...

76 FR 2440 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-13

... training courses are submitted to FAA for evaluation. The information is reviewed to determine applicant... Than Pilots. Respondents: Approximately 1,036 flight engineers and flight navigators. Frequency... and Budget. Comments should be addressed to the attention of the Desk Officer, Department of...

77 FR 36393 - Drawbridge Operation Regulation; Sacramento River, Isleton, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-19

... maintenance on the drawbridge. This deviation allows single leaf operation of the double leaf bascule style... required by 33 CFR 117.189(a). Navigation on the waterway is commercial and recreational. Either leaf of.... The opposite leaf will continue to operate normally, providing unlimited vertical clearance and 83...

78 FR 42452 - Drawbridge Operation Regulation; Sacramento River, Sacramento, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-16

... Operation Regulation; Sacramento River, Sacramento, CA AGENCY: Coast Guard, DHS. ACTION: Notice of deviation... Sacramento, CA. The deviation is necessary to allow the bridge owner to make bridge repairs. This deviation... Sacramento, CA. The drawbridge navigation span provides 109 feet vertical clearance above Mean High Water in...

Comparing taxi clearance input layouts for advancements in flight deck automation for surface operations

NASA Astrophysics Data System (ADS)

Cheng, Lara W. S.

Airport moving maps (AMMs) have been shown to decrease navigation errors, increase taxiing speed, and reduce workload when they depict airport layout, current aircraft position, and the cleared taxi route. However, current technologies are limited in their ability to depict the cleared taxi route due to the unavailability of datacomm or other means of electronically transmitting clearances from ATC to the flight deck. This study examined methods by which pilots can input ATC-issued taxi clearances to support taxi route depictions on the AMM. Sixteen general aviation (GA) pilots used a touchscreen monitor to input taxi clearances using two input layouts, softkeys and QWERTY, each with and without feedforward (graying out invalid inputs). QWERTY yielded more taxi route input errors than the softkeys layout. The presence of feedforward did not produce fewer taxi route input errors than in the non-feedforward condition. The QWERTY layout did reduce taxi clearance input times relative to the softkeys layout, but when feedforward was present this effect was observed only for the longer, 6-segment taxi clearances. It was observed that with the softkeys layout, feedforward reduced input times compared to non-feedforward but only for the 4-segment clearances. Feedforward did not support faster taxi clearance input times for the QWERTY layout. Based on the results and analyses of the present study, it is concluded that for taxi clearance inputs, (1) QWERTY remain the standard for alphanumeric inputs, and (2) feedforward be investigated further, with a focus on participant preference and performance of black-gray contrast of keys.

75 FR 15343 - Regulated Navigation Area: Narragansett Bay, RI and Mount Hope Bay, RI and MA, Including the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-29

... the transit, and a requirement to maintain a minimum underkeel clearance to prevent groundings. Based...' at Mean Lower Low Water (MLLW), and a minimum channel width of 600'. While most shoaling was removed... number of small entities. The term ``small entities'' comprises small businesses, not-for-profit...

Heli/SITAN: A Terrain Referenced Navigation algorithm for helicopters

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

Hollowell, J.

1990-01-01

Heli/SITAN is a Terrain Referenced Navigation (TRN) algorithm that utilizes radar altimeter ground clearance measurements in combination with a conventional navigation system and a stored digital terrain elevation map to accurately estimate a helicopter's position. Multiple Model Adaptive Estimation (MMAE) techniques are employed using a bank of single state Kalman filters to ensure that reliable position estimates are obtained even in the face of large initial position errors. A real-time implementation of the algorithm was tested aboard a US Army UH-1 helicopter equipped with a Singer-Kearfott Doppler Velocity Sensor (DVS) and a Litton LR-80 strapdown Attitude and Heading Reference Systemmore » (AHRS). The median radial error of the position fixes provided in real-time by this implementation was less than 50 m for a variety of mission profiles. 6 refs., 7 figs.« less

An investigation of TNAV equipped aircraft in a simulated en route metering environment

NASA Technical Reports Server (NTRS)

Groce, J. L.; Izumi, K. H.; Markham, C. H.; Schwab, R. W.; Taylor, J. A.

1986-01-01

This document presents the results of an effort to estimate how often a TNAV (Time Navigation) equipped aircraft could be given a TNAV clearance in the En Route Metering (ERM) system as a function of the percentage of arriving traffic which is TNAV equipped. A fast-time simulation of Denver Stapleton international arrival traffic in the Denver Air Route Traffic Control Center route structure, including en route metering operations, was used to develop data on estimated conflicts, clearance communications and fuel usage for traffic mixes of 25, 50, 75 and 100% TNAV equipped. This study supports an overall effort by NASA to assess the benefits and required technology for using TNAV-equipped aircraft in the ERM environment.

Comparison of a Visual and Head Tactile Display for Soldier Navigation

DTIC Science & Technology

2013-12-01

environments for nuclear power plant operators, air traffic controllers, and pilots are information intensive. These environments usually involve the indirect...queue, correcting aircraft conflicts, giving instruction, clearance and advice to pilots , and assigning aircrafts to other work queues and airports...these dynamic, complex, and multitask environments (1) collect and integrate a plethora of visual information into decisions that are critical for

Communication and Control for Fleets of Autonomous Underwater Vehicles

DTIC Science & Technology

2006-10-30

Washington State University (WSU) on fuzzy logic control systems [2-4] and autonomous vehicles [5-10]. The ALWSE-MC program developed at NAVSEA CSS was...rotating head sonar on crawlers as an additional sensor for navigation. We have previously investigated the use of video cameras on autonomous vehicles for...simulates autonomous vehicles performing mine reconnaissance/mapping, clearance, and surveillance in a littoral region. Three simulations were preformed

A graphical weather system design for the NASA transport systems research vehicle B-737

NASA Technical Reports Server (NTRS)

Scanlon, Charles H.

1992-01-01

A graphical weather system was designed for testing in the NASA Transport Systems Research Vehicle B-737 airplane and simulator. The purpose of these tests was to measure the impact of graphical weather products on aircrew decision processes, weather situation awareness, reroute clearances, workload, and weather monitoring. The flight crew graphical weather interface is described along with integration of the weather system with the flight navigation system, and data link transmission methods for sending weather data to the airplane.

Assessment of the SonixGPS system for its application in real-time ultrasonography navigation-guided percutaneous nephrolithotomy for the treatment of complex kidney stones.

PubMed

Li, Xiang; Long, Qingzhi; Chen, Xingfa; He, Dalin; He, Hui

2017-04-01

SonixGPS is a novel real-time ultrasonography navigation technology, which has been demonstrated to promote accuracy of puncture in surgical operations. The aim of this study is to evaluate its application in guiding the puncture during percutaneous nephrolithotomy (PCNL). We retrospectively reviewed our experience in treating a total of 74 patients with complex kidney stones with PCNL, in which puncture in 37 cases were guided by SonixGPS system, while the other 37 by conventional ultrasound. The effectiveness of operation was evaluated in terms of stone clearance rate, operation time, time to successful puncture, number of attempts for successful puncture and hospital stay. The safety of operation was examined by evaluating postoperative complications. Our retrospective review showed that although there were no significant differences in stone clearance rates between the groups, SonixGPS guidance resulted in more puncture accuracy with shorter puncture time and higher successful puncture rate. Under the help of SonixGPS, most patients (92 %) had no or just mild complications, compared to that (73 %) in conventional ultrasound group. Post-operative decrease of hemoglobin in SonixGPS group was 13.79 (7-33) mg/dl, significantly lower than that 20.97 (8-41) mg/dl in conventional ultrasound group. Our experience demonstrates that SonixGPS is superior to conventional ultrasound in guiding the puncture in PCNL for the treatment of complex kidney stone.

Indoor A* Pathfinding Through an Octree Representation of a Point Cloud

NASA Astrophysics Data System (ADS)

Rodenberg, O. B. P. M.; Verbree, E.; Zlatanova, S.

2016-10-01

There is a growing demand of 3D indoor pathfinding applications. Researched in the field of robotics during the last decades of the 20th century, these methods focussed on 2D navigation. Nowadays we would like to have the ability to help people navigate inside buildings or send a drone inside a building when this is too dangerous for people. What these examples have in common is that an object with a certain geometry needs to find an optimal collision free path between a start and goal point. This paper presents a new workflow for pathfinding through an octree representation of a point cloud. We applied the following steps: 1) the point cloud is processed so it fits best in an octree; 2) during the octree generation the interior empty nodes are filtered and further processed; 3) for each interior empty node the distance to the closest occupied node directly under it is computed; 4) a network graph is computed for all empty nodes; 5) the A* pathfinding algorithm is conducted. This workflow takes into account the connectivity for each node to all possible neighbours (face, edge and vertex and all sizes). Besides, a collision avoidance system is pre-processed in two steps: first, the clearance of each empty node is computed, and then the maximal crossing value between two empty neighbouring nodes is computed. The clearance is used to select interior empty nodes of appropriate size and the maximal crossing value is used to filter the network graph. Finally, both these datasets are used in A* pathfinding.

Design and flight evaluation of an integrated navigation and near-terrain helicopter guidance system for night-time and adverse weather operations

NASA Technical Reports Server (NTRS)

Swenson, Harry N.; Zelenka, Richard E.; Dearing, Munro G.; Hardy, Gordon H.; Clark, Raymond; Davis, Tom; Amatrudo, Gary; Zirkler, Andre

1994-01-01

NASA and the U.S. Army have designed, developed, and flight evaluated a Computer Aiding for Low Altitude Helicopter Flight (CALAHF) guidance system. This system provides guidance to the pilot for near terrain covert helicopter operations. It automates the processing of precision navigation information, helicopter mission requirements, and terrain flight guidance. The automation is presented to the pilot through symbology on a helmet-mounted display. The symbology is a 'pilot-centered' design which preserves pilot flexibility and authority over the CALAHF system's automation. An extensive flight evaluation of the system has been conducted using the U.S. Army's NUH-60 STAR (Systems Testbed for Avionics Research) research helicopter. The evaluations were flown over a multiwaypoint helicopter mission in rugged mountainous terrain, at terrain clearance altitudes from 300 to 125 ft and airspeeds from 40 to 110 knots. The results of these evaluations showed that the pilots could precisely follow the automation symbology while maintaining a high degree of situational awareness.

Texting during stair negotiation and implications for fall risk.

PubMed

Hashish, Rami; Toney-Bolger, Megan E; Sharpe, Sarah S; Lester, Benjamin D; Mulliken, Adam

2017-10-01

Walking requires the integration of the sensory and motor systems. Cognitive distractions have been shown to interfere with negotiation of complex walking environments, especially in populations at greater risk for falls (e.g. the elderly). With the pervasiveness of mobile messaging and the recent introduction of augmented reality mobile gaming, it is increasingly important to understand how distraction associated with the simultaneous use of a mobile device impacts navigation of the complex walking environments experienced in daily life. In this study, we investigated how gait kinematics were altered when participants performed a texting task during step negotiation. Twenty participants (13 female, 7 males) performed a series of walking trials involving a step-deck obstacle, consisting of at least 3 texting trials and 3 non-texting trials. When texting, participants ascended more slowly and demonstrated reduced dual-step foot toe clearance. Participants similarly descended more slowly when texting and demonstrated reduced single-step foot heel clearance as well as reduced dual-step foot fore-aft heel clearance. These data support the conclusion that texting during stair negotiation results in changes to gait kinematics that may increase the potential for gait disruptions, falls, and injury. Further research should examine the effect texting has on performing other common complex locomotor tasks, actual fall risk, and the patterns of resulting injury rate and severity when negotiating complex environments. Copyright © 2017 Elsevier B.V. All rights reserved.

A biomimetic vision-based hovercraft accounts for bees' complex behaviour in various corridors.

PubMed

Roubieu, Frédéric L; Serres, Julien R; Colonnier, Fabien; Franceschini, Nicolas; Viollet, Stéphane; Ruffier, Franck

2014-09-01

Here we present the first systematic comparison between the visual guidance behaviour of a biomimetic robot and those of honeybees flying in similar environments. We built a miniature hovercraft which can travel safely along corridors with various configurations. For the first time, we implemented on a real physical robot the 'lateral optic flow regulation autopilot', which we previously studied computer simulations. This autopilot inspired by the results of experiments on various species of hymenoptera consists of two intertwined feedback loops, the speed and lateral control loops, each of which has its own optic flow (OF) set-point. A heading-lock system makes the robot move straight ahead as fast as 69 cm s(-1) with a clearance from one wall as small as 31 cm, giving an unusually high translational OF value (125° s(-1)). Our biomimetic robot was found to navigate safely along straight, tapered and bent corridors, and to react appropriately to perturbations such as the lack of texture on one wall, the presence of a tapering or non-stationary section of the corridor and even a sloping terrain equivalent to a wind disturbance. The front end of the visual system consists of only two local motion sensors (LMS), one on each side. This minimalistic visual system measuring the lateral OF suffices to control both the robot's forward speed and its clearance from the walls without ever measuring any speeds or distances. We added two additional LMSs oriented at +/-45° to improve the robot's performances in stiffly tapered corridors. The simple control system accounts for worker bees' ability to navigate safely in six challenging environments: straight corridors, single walls, tapered corridors, straight corridors with part of one wall moving or missing, as well as in the presence of wind.

Integration of radar altimeter, precision navigation, and digital terrain data for low-altitude flight

NASA Technical Reports Server (NTRS)

Zelenka, Richard E.

1992-01-01

A Kalman filter for the integration of a radar altimeter into a terrain database-dependent guidance system was developed. Results obtained from a low-altitude helicopter flight test data acquired over moderately rugged terrain showed that the proposed Kalman filter removes large disparities in predicted above-ground-level (AGL) altitude in the presence of measurement anomalies and dropouts. Integration of a radar altimeter makes it possible to operate a near-terrain guidance system at or below 50 ft (subject to obstacle-avoidance limitations), whereas without radar altimeter integration, a minimum clearance altitude of 220 AGL is needed, as is suggested by previous work.

An assessment of auditory-guided locomotion in an obstacle circumvention task.

PubMed

Kolarik, Andrew J; Scarfe, Amy C; Moore, Brian C J; Pardhan, Shahina

2016-06-01

This study investigated how effectively audition can be used to guide navigation around an obstacle. Ten blindfolded normally sighted participants navigated around a 0.6 × 2 m obstacle while producing self-generated mouth click sounds. Objective movement performance was measured using a Vicon motion capture system. Performance with full vision without generating sound was used as a baseline for comparison. The obstacle's location was varied randomly from trial to trial: it was either straight ahead or 25 cm to the left or right relative to the participant. Although audition provided sufficient information to detect the obstacle and guide participants around it without collision in the majority of trials, buffer space (clearance between the shoulder and obstacle), overall movement times, and number of velocity corrections were significantly (p < 0.05) greater with auditory guidance than visual guidance. Collisions sometime occurred under auditory guidance, suggesting that audition did not always provide an accurate estimate of the space between the participant and obstacle. Unlike visual guidance, participants did not always walk around the side that afforded the most space during auditory guidance. Mean buffer space was 1.8 times higher under auditory than under visual guidance. Results suggest that sound can be used to generate buffer space when vision is unavailable, allowing navigation around an obstacle without collision in the majority of trials.

A method for performance comparison of polycentric knees and its application to the design of a knee for developing countries.

PubMed

Anand, T S; Sujatha, S

2017-08-01

Polycentric knees for transfemoral prostheses have a variety of geometries, but a survey of literature shows that there are few ways of comparing their performance. Our objective was to present a method for performance comparison of polycentric knee geometries and design a new geometry. In this work, we define parameters to compare various commercially available prosthetic knees in terms of their stability, toe clearance, maximum flexion, and so on and optimize the parameters to obtain a new knee design. We use the defined parameters and optimization to design a new knee geometry that provides the greater stability and toe clearance necessary to navigate uneven terrain which is typically encountered in developing countries. Several commercial knees were compared based on the defined parameters to determine their suitability for uneven terrain. A new knee was designed based on optimization of these parameters. Preliminary user testing indicates that the new knee is very stable and easy to use. The methodology can be used for better knee selection and design of more customized knee geometries. Clinical relevance The method provides a tool to aid in the selection and design of polycentric knees for transfemoral prostheses.

Flight Crew Factors for CTAS/FMS Integration in the Terminal Area

NASA Technical Reports Server (NTRS)

Crane, Barry W.; Prevot, Thomas; Palmer, Everett A.; Shafto, M. (Technical Monitor)

2000-01-01

Center TRACON Automation System (CTAS)/Flight Management System (FMS) integration on the flightdeck implies flight crews flying coupled in highly automated FMS modes [i.e. Vertical Navigation (VNAV) and Lateral Navigation (LNAV)] from top of descent to the final approach phase of flight. Pilots may also have to make FMS route edits and respond to datalink clearances in the Terminal Radar Approach Control (TRACON) airspace. This full mission simulator study addresses how the introduction of these FMS descent procedures affect crew activities, workload, and performance. It also assesses crew acceptance of these procedures. Results indicate that the number of crew activities and workload ratings are significantly reduced below current day levels when FMS procedures can be flown uninterrupted, but that activity numbers increase significantly above current day levels and workload ratings return to current day levels when FMS procedures are interrupted by common ATC interventions and CTAS routing advisories. Crew performance showed some problems with speed control during FMS procedures. Crew acceptance of the FMS procedures and route modification requirements was generally high; a minority of crews expressed concerns about use of VNAV in the TRACON airspace. Suggestions for future study are discussed.

Flight Evaluation of Center-TRACON Automation System Trajectory Prediction Process

NASA Technical Reports Server (NTRS)

Williams, David H.; Green, Steven M.

1998-01-01

Two flight experiments (Phase 1 in October 1992 and Phase 2 in September 1994) were conducted to evaluate the accuracy of the Center-TRACON Automation System (CTAS) trajectory prediction process. The Transport Systems Research Vehicle (TSRV) Boeing 737 based at Langley Research Center flew 57 arrival trajectories that included cruise and descent segments; at the same time, descent clearance advisories from CTAS were followed. Actual trajectories of the airplane were compared with the trajectories predicted by the CTAS trajectory synthesis algorithms and airplane Flight Management System (FMS). Trajectory prediction accuracy was evaluated over several levels of cockpit automation that ranged from a conventional cockpit to performance-based FMS vertical navigation (VNAV). Error sources and their magnitudes were identified and measured from the flight data. The major source of error during these tests was found to be the predicted winds aloft used by CTAS. The most significant effect related to flight guidance was the cross-track and turn-overshoot errors associated with conventional VOR guidance. FMS lateral navigation (LNAV) guidance significantly reduced both the cross-track and turn-overshoot error. Pilot procedures and VNAV guidance were found to significantly reduce the vertical profile errors associated with atmospheric and airplane performance model errors.

Ground Taxi Navigation Problems and Training Solutions

NASA Technical Reports Server (NTRS)

Quinn, Cheryl; Walter, Kim E.; Rosekind, Mark (Technical Monitor)

1997-01-01

Adverse weather conditions can put considerable strain on the National Airspace System. Even small decreases in visibility on the airport surface can create delays, hinder safe movement and lead to errors. Studies of Aviation Safety Reporting System (ASRS) surface movement incidents support the need for technologies and procedures to improve ground operations in low-visibility conditions. This study examined 139 ASRS reports of low-visibility surface movement incidents at 10 major U.S. airports. Errors were characterized in terms of incident type, contributing factors and consequences. The incidents in the present sample were comprised of runway transgressions, taxiway excursions and ground conflicts. The primary contributing factors were Airport Layout and Markings, Communication and Distraction. In half the incidents the controller issued a new clearance or the flight crew took an evasive action and in the remaining half, no recovery attempt was made because the error was detected after the fact. By gaining a better understanding the factors that affect crew navigation in low visibility and the types of errors that are likely to occur, it will be possible to develop more robust technologies to aid pilots in the ground taxi task. Implications for crew training and procedure development for low-visibility ground taxi are also discussed.

Under-vehicle autonomous inspection through undercarriage signatures

NASA Astrophysics Data System (ADS)

Schoenherr, Edward; Smuda, Bill

2005-05-01

Increased threats to gate security have caused recent need for improved vehicle inspection methods at security checkpoints in various fields of defense and security. A fast, reliable system of under-vehicle inspection that detects possibly harmful or unwanted materials hidden on vehicle undercarriages and notifies the user of the presence of these materials while allowing the user a safe standoff distance from the inspection site is desirable. An autonomous under-vehicle inspection system would provide for this. The proposed system would function as follows: A low-clearance tele-operated robotic platform would be equipped with sonar/laser range finding sensors as well as a video camera. As a vehicle to be inspected enters a checkpoint, the robot would autonomously navigate under the vehicle, using algorithms to detect tire locations for weigh points. During this navigation, data would be collected from the sonar/laser range finding hardware. This range data would be used to compile an impression of the vehicle undercarriage. Once this impression is complete, the system would compare it to a database of pre-scanned undercarriage impressions. Based on vehicle makes and models, any variance between the undercarriage being inspected and the impression compared against in the database would be marked as potentially threatening. If such variances exist, the robot would navigate to these locations and place the video camera in such a manner that the location in question can be viewed from a standoff position through a TV monitor. At this time, manual control of the robot navigation and camera control can be taken to imply further, more detailed inspection of the area/materials in question. After-market vehicle modifications would provide some difficulty, yet with enough pre-screening of such modifications, the system should still prove accurate. Also, impression scans that are taken in the field can be stored and tagged with a vehicles's license plate number, and future inspections of that vehicle can be compared to already screened and cleared impressions of the same vehicle in order to search for variance.

Flexible micro-OCT endobronchial probe for imaging of mucociliary transport (Conference Presentation)

NASA Astrophysics Data System (ADS)

Cui, Dongyao; Chu, Kengyeh K.; Unglert, Carolin I.; Ford, Tim N.; Carruth, Robert W.; Hyun, Daryl; Singh, Kanwarpal; Birket, Susan E.; Solomon, George M.; Rowe, Steve M.; Tearney, Guillermo J.

2016-03-01

Mucociliary clearance (MCC) plays a significant role in maintaining the health of human respiratory system by eliminating foreign particles trapped within mucus. Failure of this mechanism in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD) leads to airway blockage and lung infection, causing morbidity and mortality. The volume of airway mucus and the periciliary liquid encapsulating the cilia, in addition to ciliary beat frequency and velocity of mucociliary transport, are vital parameters of airway health. However, the diagnosis of disease pathogenesis and advances of novel therapeutics are hindered by the lack of tools for visualization of ciliary function in vivo. Our laboratory has previously developed a 1-µm resolution optical coherence tomography method, termed Micro-OCT, which is capable of visualizing mucociliary transport and quantitatively capturing epithelial functional metrics. We have also miniaturized Micro-OCT optics in a first-generation rigid 4mm Micro-OCT endoscope utilizing a common-path design and an apodizing prism configuration to produce an annular profile sample beam, and reported the first in vivo visualization of mucociliary transport in swine. We now demonstrate a flexible 2.5 mm Micro-OCT probe that can be inserted through the instrument channel of standard flexible bronchoscopes, allowing bronchoscopic navigation to smaller airways and greatly improving clinical utility. Longitudinal scanning over a field of view of more than 400 µm at a frame rate of 40 Hz was accomplished with a driveshaft transduced by a piezo-electric stack motor. We present characterization and imaging results from the flexible micro-OCT probe and progress towards clinical translation. The ability of the bronchoscope-compatible micro-OCT probe to image mucus clearance and epithelial function will enable studies of cystic fibrosis pathogenesis in small airways, provide diagnosis of mucociliary clearance disorders, and allow individual responses to treatments to be monitored.

Experimental Evaluation of an Integrated Datalink and Automation-Based Strategic Trajectory Concept

NASA Technical Reports Server (NTRS)

Mueller, Eric

2007-01-01

This paper presents research on the interoperability of trajectory-based automation concepts and technologies with modern Flight Management Systems and datalink communication available on many of today s commercial aircraft. A tight integration of trajectory-based ground automation systems with the aircraft Flight Management System through datalink will enable mid-term and far-term benefits from trajectory-based automation methods. A two-way datalink connection between the trajectory-based automation resident in the Center/TRACON Automation System and the Future Air Navigation System-1 integrated FMS/datalink in NASA Ames B747-400 Level D simulator has been established and extensive simulation of the use of datalink messages to generate strategic trajectories completed. A strategic trajectory is defined as an aircraft deviation needed to solve a conflict or honor a route request and then merge the aircraft back to its nominal preferred trajectory using a single continuous trajectory clearance. Engineers on the ground side of the datalink generated lateral and vertical trajectory clearances and transmitted them to the Flight Management System of the 747; the airborne automation then flew the new trajectory without human intervention, requiring the flight crew only to review and to accept the trajectory. This simulation established the protocols needed for a significant majority of the trajectory change types required to solve a traffic conflict or deviate around weather. This demonstration provides a basis for understanding the requirements for integration of trajectory-based automation with current Flight Management Systems and datalink to support future National Airspace System operations.

Visual tracking for multi-modality computer-assisted image guidance

NASA Astrophysics Data System (ADS)

Basafa, Ehsan; Foroughi, Pezhman; Hossbach, Martin; Bhanushali, Jasmine; Stolka, Philipp

2017-03-01

With optical cameras, many interventional navigation tasks previously relying on EM, optical, or mechanical guidance can be performed robustly, quickly, and conveniently. We developed a family of novel guidance systems based on wide-spectrum cameras and vision algorithms for real-time tracking of interventional instruments and multi-modality markers. These navigation systems support the localization of anatomical targets, support placement of imaging probe and instruments, and provide fusion imaging. The unique architecture - low-cost, miniature, in-hand stereo vision cameras fitted directly to imaging probes - allows for an intuitive workflow that fits a wide variety of specialties such as anesthesiology, interventional radiology, interventional oncology, emergency medicine, urology, and others, many of which see increasing pressure to utilize medical imaging and especially ultrasound, but have yet to develop the requisite skills for reliable success. We developed a modular system, consisting of hardware (the Optical Head containing the mini cameras) and software (components for visual instrument tracking with or without specialized visual features, fully automated marker segmentation from a variety of 3D imaging modalities, visual observation of meshes of widely separated markers, instant automatic registration, and target tracking and guidance on real-time multi-modality fusion views). From these components, we implemented a family of distinct clinical and pre-clinical systems (for combinations of ultrasound, CT, CBCT, and MRI), most of which have international regulatory clearance for clinical use. We present technical and clinical results on phantoms, ex- and in-vivo animals, and patients.

Do characteristics of a stationary obstacle lead to adjustments in obstacle stepping strategies?

PubMed

Worden, Timothy A; De Jong, Audrey F; Vallis, Lori Ann

2016-01-01

Navigating cluttered and complex environments increases the risk of falling. To decrease this risk, it is important to understand the influence of obstacle visual cues on stepping parameters, however the specific obstacle characteristics that have the greatest influence on avoidance strategies is still under debate. The purpose of the current work is to provide further insight on the relationship between obstacle appearance in the environment and modulation of stepping parameters. Healthy young adults (N=8) first stepped over an obstacle with one visible top edge ("floating"; 8 trials) followed by trials where experimenters randomly altered the location of a ground reference object to one of 7 different positions (8 trials per location), which ranged from 6cm in front of, directly under, or up to 6cm behind the floating obstacle (at 2cm intervals). Mean take-off and landing distance as well as minimum foot clearance values were unchanged across different positions of the ground reference object; a consistent stepping trajectory was observed for all experimental conditions. Contrary to our hypotheses, results of this study indicate that ground based visual cues are not essential for the planning of stepping and clearance strategies. The simultaneous presentation of both floating and ground based objects may have provided critical information that lead to the adoption of a consistent strategy for clearing the top edge of the obstacle. The invariant foot placement observed here may be an appropriate stepping strategy for young adults, however this may not be the case across the lifespan or in special populations. Copyright © 2015 Elsevier B.V. All rights reserved.

Experimental Evaluation of CTAS/FMS Integration in TRACON Airspace

NASA Technical Reports Server (NTRS)

Romahn, Stephen; Palmer, Everett; Null, Cynthia H. (Technical Monitor)

1999-01-01

A CTAS/FMS integration project at Ames Research Center addresses extensions to the CTAS air traffic management concept, among them the introduction of arrival routes specially designed for the use with a Flight Management System. These FMS arrival routes shall allow for the use of the INS' lateral and vertical navigation capabilities throughout the arrival until final approach. For the use in this project CTAS controller support tools that compliment the concept have been created. These tools offer controllers access to CTAS' prediction and planning capabilities in terms of speed and route advisories. The objective is to allow for a more strategic way of controlling aircraft. Expected benefits are an increase in arrival rate and a reduction of average travel times through TRACER airspace. A real time simulation is being conducted at Ames to investigate how FMS arrivals and approach transitions - with and without the support of CTAS tools - effect the flow of arriving traffic within TRACER airspace and the controllers' task performance. Four conditions will be investigated and compared to today's technique of controlling traffic with tactical vectoring: 1. FMS arrivals and approach transitions are available for controllers to issue to equipped aircraft - traffic permitting; 2. Speed advisories that match CTAS' runway balancing and sequencing plan are displayed to Feeder controllers; 3. Approach transition advisories (e.g., location of the base turn point) are displayed to Final controllers for tactical clearances ("Turn base now"); and 4. Approach transition advisories (voice and data link) are generated by CTAS and displayed to final controllers for strategic voice clearances ("Turn base five miles after waypoint xyz") or prepared in terms of a trajectory description for strategic data link clearance. Scenarios used in the study will represent current traffic and vary in density of arriving traffic and the kind and mix of equipage of arriving aircraft. Data will be collected from experiment runs with active TRACON controllers on the final approach spacing, the aircraft's speed profiles, the controllers interaction with CTAS tools, and number and timing of pilot controllers communications under the described conditions.

Quantification of glomerular filtration rate by measurement of gadobutrol clearance from the extracellular fluid volume: comparison of a TurboFLASH and a TrueFISP approach

NASA Astrophysics Data System (ADS)

Boss, Andreas; Martirosian, Petros; Artunc, Ferruh; Risler, Teut; Claussen, Claus D.; Schlemmer, Heinz-Peter; Schick, Fritz

2007-03-01

Purpose: As the MR contrast-medium gadobutrol is completely eliminated via glomerular filtration, the glomerular filtration rate (GFR) can be quantified after bolus-injection of gadobutrol and complete mixing in the extracellular fluid volume (ECFV) by measuring the signal decrease within the liver parenchyma. Two different navigator-gated single-shot saturation-recovery sequences have been tested for suitability of GFR quantification: a TurboFLASH and a TrueFISP readout technique. Materials and Methods: Ten healthy volunteers (mean age 26.1+/-3.6) were equally devided in two subgroups. After bolus-injection of 0.05 mmol/kg gadobutrol, coronal single-slice images of the liver were recorded every 4-5 seconds during free breathing using either the TurboFLASH or the TrueFISP technique. Time-intensity curves were determined from manually drawn regions-of-interest over the liver parenchyma. Both sequences were subsequently evaluated regarding signal to noise ratio (SNR) and the behaviour of signal intensity curves. The calculated GFR values were compared to an iopromide clearance gold standard. Results: The TrueFISP sequence exhibited a 3.4-fold higher SNR as compared to the TurboFLASH sequence and markedly lower variability of the recorded time-intensity curves. The calculated mean GFR values were 107.0+/-16.1 ml/min/1.73m2 (iopromide: 92.1+/-14.5 ml/min/1.73m2) for the TrueFISP technique and 125.6+/-24.1 ml/min/1.73m2 (iopromide: 97.7+/-6.3 ml/min/1.73m2) for the TurboFLASH approach. The mean paired differences with TrueFISP was lower (15.0 ml/min/1.73m2) than in the TurboFLASH method (27.9 ml/min/1.73m2). Conclusion: The global GFR can be quantified via measurement of gadobutrol clearance from the ECFV. A saturation-recovery TrueFISP sequence allows for more reliable GFR quantification as a saturation recovery TurboFLASH technique.

Determination of glomerular function in advanced renal failure.

PubMed Central

Manz, F; Alatas, H; Kochen, W; Lutz, P; Rebien, W; Schärer, K

1977-01-01

In 15 children with advanced chronic renal failure, glomerular filtration rate was determined by different methods. Inulin clearance correlated well with the mean of creatinine and urea clearance, and also with 51-chromium edetic acid (EDTA) clearance measured over 24 hours. The absolute values of creatinine clearance and of 51Cr-EDTA clearance measured up to 8 hours were higher than inulin clearance. In advanced renal failure both the 51Cr-EDTA clearance measured over 24 hours, and the mean of creatinine and urea clearance, provide acceptable estimates of true glomerular filtration rate. PMID:411426

Effect of Internal Clearance on Load Distribution and Life of Radially Loaded Ball and Roller Bearings

NASA Technical Reports Server (NTRS)

Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

2012-01-01

The effect of internal clearance on radially loaded deepgroove ball and cylindrical roller bearing load distribution and fatigue life was determined for four clearance groups defined in the bearing standards. The analysis was extended to negative clearance (interference) conditions to produce a curve of life factor versus internal clearance. Rolling-element loads can be optimized and bearing life maximized for a small negative operating clearance. Life declines gradually with positive clearance and rapidly with increasing negative clearance. Relationships were found between bearing life and internal clearance as a function of ball or roller diameter, adjusted for load. Results are presented as life factors for radially loaded bearings independent of bearing size or applied load. In addition, a modified Stribeck Equation is presented that relates the maximum rolling-element load to internal bearing clearance.

Online monitoring of dynamic tip clearance of turbine blades in high temperature environments

NASA Astrophysics Data System (ADS)

Han, Yu; Zhong, Chong; Zhu, Xiaoliang; Zhe, Jiang

2018-04-01

Minimized tip clearance reduces the gas leakage over turbine blade tips and improves the thrust and efficiency of turbomachinery. An accurate tip clearance sensor, measuring the dynamic clearances between blade tips and the turbine case, is a critical component for tip clearance control. This paper presents a robust inductive tip clearance sensor capable of monitoring dynamic tip clearances of turbine machines in high-temperature environments and at high rotational speeds. The sensor can also self-sense the temperature at a blade tip in situ such that temperature effect on tip clearance measurement can be estimated and compensated. To evaluate the sensor’s performance, the sensor was tested for measuring the tip clearances of turbine blades under various working temperatures ranging from 700 K to 1300 K and at turbine rotational speeds ranging from 3000 to 10 000 rpm. The blade tip clearance was varied from 50 to 2000 µm. The experiment results proved that the sensor can accurately measure the blade tip clearances with a temporal resolution of 10 µm. The capability of accurately measuring the tip clearances at high temperatures (~1300 K) and high turbine rotation speeds (~30 000 rpm), along with its compact size, makes it promising for online monitoring and active control of blade tip clearances of high-temperature turbomachinery.

Lactate clearance as a marker of mortality in pediatric intensive care unit.

PubMed

Munde, A; Kumar, N; Beri, R S; Puliyel, J M

2014-07-01

To correlate lactate clearance with Pediatric Intensive Care Unit (PICU) mortality. 45 (mean age 40.15 mo, 60% males) consecutive admissions in the PICU were enrolled between May 2012 to June 2013. Lactate clearance (Lactate level at admission - level 6 hr later x 100 / lactate level at admission) in first 6 hours of hospitalization was correlated to in-hospital mortality and PRISM score. Twelve out of 45 patients died. 90% died among those with delayed/poor clearance (clearance <30%) compared to 8.5% in those with good clearance (clearance >30%) (P<0.001). Lactate clearance <30% predicted mortality with sensitivity of 75%, specificity of 97%, positive predictive value of 90%, and negative predictive value of 91.42%. Predictability was comparable to PRISM score >30. Lactate clearance at six hours correlates with mortality in the PICU.

14 CFR 25.925 - Propeller clearance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most adverse...

14 CFR 23.925 - Propeller clearance.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the most...

14 CFR 23.925 - Propeller clearance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the most...

14 CFR 23.925 - Propeller clearance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the most...

14 CFR 25.925 - Propeller clearance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most adverse...

14 CFR 25.925 - Propeller clearance.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most adverse...

14 CFR 25.925 - Propeller clearance.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most adverse...

14 CFR 23.925 - Propeller clearance.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the most...

48 CFR 945.603-70 - Plant clearance function.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Plant clearance function... Plant clearance function. If the plant clearance function has not been formally delegated to another Federal agency, the contracting officer shall assume all responsibilities of the plant clearance officer...

48 CFR 945.603-70 - Plant clearance function.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Plant clearance function... Plant clearance function. If the plant clearance function has not been formally delegated to another Federal agency, the contracting officer shall assume all responsibilities of the plant clearance officer...

Carbon Nanotubes in the Human Respiratory Tract-Clearance Modeling.

PubMed

Sturm, Robert

2017-03-01

Clearance of single-wall carbon nanotubes (SWCNT, diameter: 5 nm) and multi-wall carbon nanotubes (MWCNT, diameter: 50 nm) in the respiratory tract was predicted for various age groups (infants, children, adolescents, and adults). The model was founded on the assumption that lung clearance takes place in three distinct phases: (i) fast mucociliary clearance, (ii) slow bronchial clearance, and (iii) alveolar clearance. To each of these phases a specific fraction of deposited particles was attributed, the amount of which depended on particles' geometry and particles' deposition sites in the respiratory system. Clearance velocities were expressed by respective clearance half-times ranging from several hours in the case of fast clearance to tens of days in the case of slow clearance. Results of the simulations clearly demonstrate that for the specific deposition scenario (sitting, nasal breathing) considered here fast clearance fraction exhibits a slight decrease with increasing age, but total clearance times (i.e. time spans, within which 100% of the deposited particulate mass are removed) are rather constant among the age groups. Nanotubes deposited in the respiratory bronchioles and alveoli are usually subject to a long-term storage in these structures and, thus, may trigger malignant transformations in adjacent cells and tissues. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

The Canadian Forces ILDS: a militarily fielded multisensor vehicle-mounted teleoperated landmine detection system

NASA Astrophysics Data System (ADS)

McFee, John E.; Russell, Kevin L.; Chesney, Robert H.; Faust, Anthony A.; Das, Yogadhish

2006-05-01

The Improved Landmine Detection System (ILDS) is intended to meet Canadian military mine clearance requirements in rear area combat situations and peacekeeping on roads and tracks. The system consists of two teleoperated vehicles and a command vehicle. The teleoperated protection vehicle precedes, clearing antipersonnel mines and magnetic and tilt rod-fuzed antitank mines. It consists of an armoured personnel carrier with a forward looking infrared imager, a finger plow or roller and a magnetic signature duplicator. The teleoperated detection vehicle follows to detect antitank mines. The purpose-built vehicle carries forward looking infrared and visible imagers, a 3 m wide, down-looking sensitive electromagnetic induction detector array and a 3 m wide down-looking ground probing radar, which scan the ground in front of the vehicle. Sensor information is combined using navigation sensors and custom navigation, registration, spatial correspondence and data fusion algorithms. Suspicious targets are then confirmed by a thermal neutron activation detector. The prototype, designed and built by Defence R&D Canada, was completed in October 1997. General Dynamics Canada delivered four production units, based on the prototype concept and technologies, to the Canadian Forces (CF) in 2002. ILDS was deployed in Afghanistan in 2003, making the system the first militarily fielded, teleoperated, multi-sensor vehicle-mounted mine detector and the first with a fielded confirmation sensor. Performance of the prototype in Canadian and independent US trials is summarized and recent results from the production version of the confirmation sensor are discussed. CF operations with ILDS in Afghanistan are described.

Creatinine clearance test

MedlinePlus

Serum creatinine clearance; Kidney function - creatinine clearance; Renal function - creatinine clearance ... the body entirely by the kidneys. If kidney function is abnormal, creatinine level increases in the blood ...

Toxicokinetics of PAHs in Hexagenia

USGS Publications Warehouse

Stehly, Guy R.; Landrum, Peter F.; Henry, Mary G.; Klemm, C.

1990-01-01

The clearance of oxygen from water is inversely and linearly related to the weight of the mayfly nymphs, but oxygen clearances were always much less than the uptake clearances of the PAHs. The high PAH uptake clearance compared to oxygen clearance implies a greater surface area or efficiency for PAH accumulation from water.

48 CFR 801.602-76 - Business clearance review.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Business clearance review... Authority, and Responsibilities 801.602-76 Business clearance review. (a) A business clearance review is a... obtain a business clearance review prior to award of any contract, task or delivery order, or blanket...

48 CFR 801.602-76 - Business clearance review.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Business clearance review... Authority, and Responsibilities 801.602-76 Business clearance review. (a) A business clearance review is a... obtain a business clearance review prior to award of any contract, task or delivery order, or blanket...

Railway Tunnel Clearance Inspection Method Based on 3D Point Cloud from Mobile Laser Scanning

PubMed Central

Zhou, Yuhui; Wang, Shaohua; Mei, Xi; Yin, Wangling; Lin, Chunfeng; Mao, Qingzhou

2017-01-01

Railway tunnel clearance is directly related to the safe operation of trains and upgrading of freight capacity. As more and more railway are put into operation and the operation is continuously becoming faster, the railway tunnel clearance inspection should be more precise and efficient. In view of the problems existing in traditional tunnel clearance inspection methods, such as low density, slow speed and a lot of manual operations, this paper proposes a tunnel clearance inspection approach based on 3D point clouds obtained by a mobile laser scanning system (MLS). First, a dynamic coordinate system for railway tunnel clearance inspection has been proposed. A rail line extraction algorithm based on 3D linear fitting is implemented from the segmented point cloud to establish a dynamic clearance coordinate system. Second, a method to seamlessly connect all rail segments based on the railway clearance restrictions, and a seamless rail alignment is formed sequentially from the middle tunnel section to both ends. Finally, based on the rail alignment and the track clearance coordinate system, different types of clearance frames are introduced for intrusion operation with the tunnel section to realize the tunnel clearance inspection. By taking the Shuanghekou Tunnel of the Chengdu–Kunming Railway as an example, when the clearance inspection is carried out by the method mentioned herein, its precision can reach 0.03 m, and difference types of clearances can be effectively calculated. This method has a wide application prospects. PMID:28880232

Evaluation of an Active Clearance Control System Concept

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Lattime, Scott B.; DeCastro, Jonathan A.; Oswald, Jay; Melcher, Kevin J.

2005-01-01

Reducing blade tip clearances through active tip clearance control in the high pressure turbine can lead to significant reductions in emissions and specific fuel consumption as well as dramatic improvements in operating efficiency and increased service life. Current engines employ scheduled cooling of the outer case flanges to reduce high pressure turbine tip clearances during cruise conditions. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold build clearances to set the minimum clearances at extreme operating conditions (e.g., takeoff, reburst) and not allowing cruise clearances to be minimized due to the possibility of throttle transients (e.g., step change in altitude). In an effort to improve upon current thermal methods, a first generation mechanically-actuated active clearance control (ACC) system has been designed and fabricated. The system utilizes independent actuators, a segmented shroud structure, and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. Ambient temperature performance tests of this first generation ACC system assessed individual seal component leakage rates and both static and dynamic overall system leakage rates. The ability of the nine electric stepper motors to control the position of the seal carriers in both open- and closed-loop control modes for single and multiple cycles was investigated. The ability of the system to follow simulated engine clearance transients in closed-loop mode showed the system was able to track clearances to within a tight tolerance (0.001 in. error).

Evaluation of an Active Clearance Control System Concept

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Lattime, Scott B.; Taylor, Shawn; DeCastro, Jonathan A.; Oswald, Jay; Melcher, Kevin J.

2005-01-01

Reducing blade tip clearances through active tip clearance control in the high pressure turbine can lead to significant reductions in emissions and specific fuel consumption as well as dramatic improvements in operating efficiency and increased service life. Current engines employ scheduled cooling of the outer case flanges to reduce high pressure turbine tip clearances during cruise conditions. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold build clearances to set the minimum clearances at extreme operating conditions (e.g., takeoff, reburst) and not allowing cruise clearances to be minimized due to the possibility of throttle transients (e.g., step change in altitude). In an effort to improve upon current thermal methods, a first generation mechanically-actuated active clearance control (ACC) system has been designed and fabricated. The system utilizes independent actuators, a segmented shroud structure, and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. Ambient temperature performance tests of this first generation ACC system assessed individual seal component leakage rates and both static and dynamic overall system leakage rates. The ability of the nine electric stepper motors to control the position of the seal carriers in both open- and closed-loop control modes for single and multiple cycles was investigated. The ability of the system to follow simulated engine clearance transients in closed-loop mode showed the system was able to track clearances to within a tight tolerance ( 0.001 in. error).

A parameters optimization method for planar joint clearance model and its application for dynamics simulation of reciprocating compressor

NASA Astrophysics Data System (ADS)

Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li

2015-05-01

In order to improve the accuracy of dynamics response simulation for mechanism with joint clearance, a parameter optimization method for planar joint clearance contact force model was presented in this paper, and the optimized parameters were applied to the dynamics response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the dynamic equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body dynamic model built in ADAMS software was used to solve this equation. To obtain a simulated dynamic response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were optimized by genetic algorithms approach. Finally, the optimized parameters were applied to simulate the dynamics response of model with oversized joint clearance fault according to the concluded parameter relation. The dynamics response of experimental test verified the effectiveness of this application.

Clinical review: Drug metabolism and nonrenal clearance in acute kidney injury

PubMed Central

Vilay, A Mary; Churchwell, Mariann D; Mueller, Bruce A

2008-01-01

Decreased renal drug clearance is an obvious consequence of acute kidney injury (AKI). However, there is growing evidence to suggest that nonrenal drug clearance is also affected. Data derived from human and animal studies suggest that hepatic drug metabolism and transporter function are components of nonrenal clearance affected by AKI. Acute kidney injury may also impair the clearance of formed metabolites. The fact that AKI does not solely influence kidney function may have important implications for drug dosing, not only of renally eliminated drugs but also of those that are hepatically cleared. A review of the literature addressing the topic of drug metabolism and clearance alterations in AKI reveals that changes in nonrenal clearance are highly complicated and poorly studied, but they may be quite common. At present, our understanding of how AKI affects drug metabolism and nonrenal clearance is limited. However, based on the available evidence, clinicians should be cognizant that even hepatically eliminated drugs and formed drug metabolites may accumulate during AKI, and renal replacement therapy may affect nonrenal clearance as well as drug metabolite clearance. PMID:19040780

A Matter of Millimeters: Defining the Processes for Critical Clearances on Curiosity

NASA Technical Reports Server (NTRS)

Florow, Brandon

2013-01-01

The Mars Science Laboratory (MSL) mission presents an immense packaging problem in that it takes a rover the size of a car with a sky crane landing system and packs it tightly into a spacecraft. This creates many areas of close and critical clearances. Critical Clearances are defined as hardware-to-hardware or hardware-to-envelope clearances which fall below a pre-established location dependent threshold and pose a risk of hardware to hardware contact during events such as launch, entry, landing, and operations. Close Clearances, on the other hand, are defined as any clearance value that is chosen to be tracked but is larger than the critical clearance threshold for its region. Close clearances may be tracked for various reasons including uncertainty in design, large expected dynamic motion, etc.

N-linked glycan truncation causes enhanced clearance of plasma-derived von Willebrand factor.

PubMed

O'Sullivan, J M; Aguila, S; McRae, E; Ward, S E; Rawley, O; Fallon, P G; Brophy, T M; Preston, R J S; Brady, L; Sheils, O; Chion, A; O'Donnell, J S

2016-12-01

Essentials von Willebrands factor (VWF) glycosylation plays a key role in modulating in vivo clearance. VWF glycoforms were used to examine the role of specific glycan moieties in regulating clearance. Reduction in sialylation resulted in enhanced VWF clearance through asialoglycoprotein receptor. Progressive VWF N-linked glycan trimming resulted in increased macrophage-mediated clearance. Click to hear Dr Denis discuss clearance of von Willebrand factor in a free presentation from the ISTH Academy SUMMARY: Background Enhanced von Willebrand factor (VWF) clearance is important in the etiology of both type 1 and type 2 von Willebrand disease (VWD). In addition, previous studies have demonstrated that VWF glycans play a key role in regulating in vivo clearance. However, the molecular mechanisms underlying VWF clearance remain poorly understood. Objective To define the molecular mechanisms through which VWF N-linked glycan structures influence in vivo clearance. Methods By use of a series of exoglycosidases, different plasma-derived VWF (pd-VWF) glycoforms were generated. In vivo clearance of these glycoforms was then assessed in VWF -/- mice in the presence or absence of inhibitors of asialoglycoprotein receptor (ASGPR), or following clodronate-induced macrophage depletion. Results Reduced amounts of N-linked and O-linked sialylation resulted in enhanced pd-VWF clearance modulated via ASGPR. In addition to this role of terminal sialylation, we further observed that progressive N-linked glycan trimming also resulted in markedly enhanced VWF clearance. Furthermore, these additional N-linked glycan effects on clearance were ASGPR-independent, and instead involved enhanced macrophage clearance that was mediated, at least in part, through LDL receptor-related protein 1. Conclusion The carbohydrate determinants expressed on VWF regulate susceptibility to proteolysis by ADAMTS-13. In addition, our findings now further demonstrate that non-sialic acid carbohydrate determinants expressed on VWF also play an unexpectedly important role in modulating in vivo clearance through both hepatic ASGPR-dependent and macrophage-dependent pathways. In addition, these data further support the hypothesis that variation in VWF glycosylation may be important in the pathophysiology underlying type 1C VWD. © 2016 International Society on Thrombosis and Haemostasis.

Chaos vibration of pinion and rack steering trapezoidal mechanism containing two clearances

NASA Astrophysics Data System (ADS)

Wei, Daogao; Wang, Yu; Jiang, Tong; Zheng, Sifa; Zhao, Wenjing; Pan, Zhijie

2017-08-01

The multi-clearances of breaking type steering trapezoidal mechanism joints influences vehicle steering stability. Hence, to ascertain the influence of clearance value on steering stability, this paper takes the steering mechanism of a certain vehicle type as a prototype that can be simplified into a planar six-bar linkage, then establishes the system dynamic differential equations after considering the two clearances of tie rods and the steering knuckle arms. The influence of the clearance parameters on the movement stability of the steering mechanism is studied using a numerical computation method. Results show that when the two clearances are equal, the planar movement of the tie rods changes from period-doubling to chaos as the clearances increase. When the two clearances are 0.25 mm and 1.5 mm respectively, the planar movements of the two side tie rods come into chaos, causing the steering stability to deteriorate. Moreover, with the increase of clearances, turning moment fluctuates more intensively and the peak value increases.

Numerical investigation of tip clearance effects on the performance of ducted propeller

NASA Astrophysics Data System (ADS)

Ding, Yongle; Song, Baowei; Wang, Peng

2015-09-01

Tip clearance loss is a limitation of the improvement of turbomachine performance. Previous studies show the Tip clearance loss is generated by the leakage flow through the tip clearance, and is roughly linearly proportional to the gap size. This study investigates the tip clearance effects on the performance of ducted propeller. The investigation was carried out by solving the Navier-Stokes equations with the commercial Computational Fluid Dynamic (CFD) code CFX14.5. These simulations were carried out to determine the underlying mechanisms of the tip clearance effects. The calculations were performed at three different chosen advance ratios. Simulation results showed that the tip loss slope was not linearly at high advance due to the reversed pressure at the leading edge. Three type of vortical structures were observed in the tip clearance at different clearance size.

Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts

NASA Technical Reports Server (NTRS)

Lattime, Scott B.; Steinetz, Bruce M.; Robbie, Malcolm G.

2003-01-01

Improved blade tip sealing in the high pressure compressor and high pressure turbine can provide dramatic improvements in specific fuel consumption, time-on-wing, compressor stall margin and engine efficiency as well as increased payload and mission range capabilities of both military and commercial gas turbine engines. The preliminary design of a mechanically actuated active clearance control (ACC) system for turbine blade tip clearance management is presented along with the design of a bench top test rig in which the system is to be evaluated. The ACC system utilizes mechanically actuated seal carrier segments and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. The purpose of this active clearance control system is to improve upon current case cooling methods. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold build clearances to set the minimum clearances at extreme operating conditions (e.g., takeoff, re-burst) and not allowing cruise clearances to be minimized due to the possibility of throttle transients (e.g., step change in altitude). The active turbine blade tip clearance control system design presented herein will be evaluated to ensure that proper response and positional accuracy is achievable under simulated high-pressure turbine conditions. The test rig will simulate proper seal carrier pressure and temperature loading as well as the magnitudes and rates of blade tip clearance changes of an actual gas turbine engine. The results of these evaluations will be presented in future works.

Design optimization of dual-axis driving mechanism for satellite antenna with two planar revolute clearance joints

NASA Astrophysics Data System (ADS)

Bai, Zheng Feng; Zhao, Ji Jun; Chen, Jun; Zhao, Yang

2018-03-01

In the dynamic analysis of satellite antenna dual-axis driving mechanism, it is usually assumed that the joints are ideal or perfect without clearances. However, in reality, clearances in joints are unavoidable due to assemblage, manufacturing errors and wear. When clearance is introduced to the mechanism, it will lead to poor dynamic performances and undesirable vibrations due to impact forces in clearance joint. In this paper, a design optimization method is presented to reduce the undesirable vibrations of satellite antenna considering clearance joints in dual-axis driving mechanism. The contact force model in clearance joint is established using a nonlinear spring-damper model and the friction effect is considered using a modified Coulomb friction model. Firstly, the effects of clearances on dynamic responses of satellite antenna are investigated. Then the optimization method for dynamic design of the dual-axis driving mechanism with clearance is presented. The objective of the optimization is to minimize the maximum absolute vibration peak of antenna acceleration by reducing the impact forces in clearance joint. The main consideration here is to optimize the contact parameters of the joint elements. The contact stiffness coefficient, damping coefficient and the dynamic friction coefficient for clearance joint elements are taken as the optimization variables. A Generalized Reduced Gradient (GRG) algorithm is used to solve this highly nonlinear optimization problem for dual-axis driving mechanism with clearance joints. The results show that the acceleration peaks of satellite antenna and contact forces in clearance joints are reduced obviously after design optimization, which contributes to a better performance of the satellite antenna. Also, the application and limitation of the proposed optimization method are discussed.

Relationship between rhinosinusitis symptoms and mucociliary clearance time.

PubMed

Boatsman, Justin E; Calhoun, Karen H; Ryan, Matthew W

2006-03-01

To determine the correlation between rhinosinusitis symptoms as assessed by the Sino-Nasal Outcomes Test-20 (SNOT-20) and mucociliary clearance as assessed by the saccharin method. This was a cross-sectional study of 50 adult volunteers. Subjects completed the SNOT-20, and mucociliary clearance was determined with the saccharine method. Correlation coefficients (Spearman's Rho) were calculated for the global SNOT-20 score. The SNOT-20 scores varied from 20 to 54 (mean 30.28) with a possible range of 20 to 100. Clearance times varied from 418 to 2865 seconds (mean 999). There was no significant correlation between global SNOT-20 score and clearance time (r = 0.196). There is no significant correlation between rhinosinusitis symptoms as assessed by SNOT-20 scores and mucociliary clearance. Mucociliary clearance is important for the health of the sinonasal cavities, but clearance time does not appear to be associated with symptom severity in the population studied. A-1b.

48 CFR 245.602-70 - Plant clearance procedures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Plant clearance procedures... Disposal 245.602-70 Plant clearance procedures. Follow the procedures at PGI 245.602-70 for establishing and processing a plant clearance case. ...

48 CFR 245.602-70 - Plant clearance procedures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Plant clearance procedures... Disposal 245.602-70 Plant clearance procedures. Follow the procedures at PGI 245.602-70 for establishing and processing a plant clearance case. ...

48 CFR 245.602-70 - Plant clearance procedures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Plant clearance procedures... Disposal 245.602-70 Plant clearance procedures. Follow the procedures at PGI 245.602-70 for establishing and processing a plant clearance case. ...

48 CFR 245.602-70 - Plant clearance procedures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Plant clearance procedures... Disposal 245.602-70 Plant clearance procedures. Follow the procedures at PGI 245.602-70 for establishing and processing a plant clearance case. ...

78 FR 77027 - Overhead Clearance (Air-Draft) Accidents

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-20

... No. USCG-2013-0466] Overhead Clearance (Air-Draft) Accidents AGENCY: Coast Guard, DHS. ACTION... clearance (air-draft) accidents. In its petition, which calls for vessel masters to be provided with accurate vertical air draft information, a maritime organization has described 16 overhead clearance...

30 CFR 18.24 - Electrical clearances.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Electrical clearances. 18.24 Section 18.24... APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.24 Electrical clearances. Minimum clearances between uninsulated electrical conductor...

30 CFR 18.24 - Electrical clearances.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Electrical clearances. 18.24 Section 18.24... APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.24 Electrical clearances. Minimum clearances between uninsulated electrical conductor...

30 CFR 18.24 - Electrical clearances.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Electrical clearances. 18.24 Section 18.24... APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.24 Electrical clearances. Minimum clearances between uninsulated electrical conductor...

Numerical investigation of hub clearance flow in a Kaplan turbine

NASA Astrophysics Data System (ADS)

Wu, H.; Feng, J. J.; Wu, G. K.; Luo, X. Q.

2012-11-01

In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

CF6 High Pressure Compressor and Turbine Clearance Evaluations

NASA Technical Reports Server (NTRS)

Radomski, M. A.; Cline, L. D.

1981-01-01

In the CF6 Jet Engine Diagnostics Program the causes of performance degradation were determined for each component of revenue service engines. It was found that a significant contribution to performance degradation was caused by increased airfoil tip radial clearances in the high pressure compressor and turbine areas. Since the influence of these clearances on engine performance and fuel consumption is significant, it is important to accurately establish these relatonships. It is equally important to understand the causes of clearance deterioration so that they can be reduced or eliminated. The results of factory engine tests run to enhance the understanding of the high pressure compressor and turbine clearance effects on performance are described. The causes of clearance deterioration are indicated and potential improvements in clearance control are discussed.

Cerebrospinal Fluid Clearance in Alzheimer Disease Measured with Dynamic PET.

PubMed

de Leon, Mony J; Li, Yi; Okamura, Nobuyuki; Tsui, Wai H; Saint-Louis, Les A; Glodzik, Lidia; Osorio, Ricardo S; Fortea, Juan; Butler, Tracy; Pirraglia, Elizabeth; Fossati, Silvia; Kim, Hee-Jin; Carare, Roxana O; Nedergaard, Maiken; Benveniste, Helene; Rusinek, Henry

2017-09-01

Evidence supporting the hypothesis that reduced cerebrospinal fluid (CSF) clearance is involved in the pathophysiology of Alzheimer disease (AD) comes primarily from rodent models. However, unlike rodents, in which predominant extracranial CSF egress is via olfactory nerves traversing the cribriform plate, human CSF clearance pathways are not well characterized. Dynamic PET with 18 F-THK5117, a tracer for tau pathology, was used to estimate the ventricular CSF time-activity as a biomarker for CSF clearance. We tested 3 hypotheses: extracranial CSF is detected at the superior turbinates; CSF clearance is reduced in AD; and CSF clearance is inversely associated with amyloid deposition. Methods: Fifteen subjects, 8 with AD and 7 normal control volunteers, were examined with 18 F-THK5117. Ten subjects additionally underwent 11 C-Pittsburgh compound B ( 11 C-PiB) PET scanning, and 8 were 11 C-PiB-positive. Ventricular time-activity curves of 18 F-THK5117 were used to identify highly correlated time-activity curves from extracranial voxels. Results: For all subjects, the greatest density of CSF-positive extracranial voxels was in the nasal turbinates. Tracer concentration analyses validated the superior nasal turbinate CSF signal intensity. AD patients showed ventricular tracer clearance reduced by 23% and 66% fewer superior turbinate CSF egress sites. Ventricular CSF clearance was inversely associated with amyloid deposition. Conclusion: The human nasal turbinate is part of the CSF clearance system. Lateral ventricle and superior nasal turbinate CSF clearance abnormalities are found in AD. Ventricular CSF clearance reductions are associated with increased brain amyloid depositions. These data suggest that PET-measured CSF clearance is a biomarker of potential interest in AD and other neurodegenerative diseases. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

The fate of sulfate in chronic heart failure

PubMed Central

Koning, Anne M.; Meijers, Wouter C.; Minović, Isidor; Post, Adrian; Feelisch, Martin; Pasch, Andreas; Leuvenink, Henri G. D.; de Boer, Rudolf A.; Bakker, Stephan J. L.

2017-01-01

New leads to advance our understanding of heart failure (HF) pathophysiology are urgently needed. Previous studies have linked urinary sulfate excretion to a favorable cardiovascular risk profile. Sulfate is not only the end product of hydrogen sulfide metabolism but is also directly involved in various (patho)physiological processes, provoking scientific interest in its renal handling. This study investigates sulfate clearance in chronic HF (CHF) patients and healthy individuals and considers its relationship with disease outcome. Parameters related to renal sulfate handling were determined in and compared between 96 previously characterized CHF patients and sex-matched healthy individuals. Among patients, sulfate clearance was analyzed for associations with clinical and outcome parameters. In CHF patients, plasma sulfate concentrations are significantly higher, whereas 24-h urinary excretion, fractional excretion, and clearance of sulfate are significantly lower, compared with healthy individuals. Among patients, sulfate clearance is independently associated with diuretics use, creatinine clearance and 24-h urinary sodium excretion. Sulfate clearance is associated with favorable disease outcome [hazard ratio per SD increase 0.38 (95% confidence interval 0.23–0.63), P < 0.001]. Although significance was lost after adjustment for creatinine clearance, the decrease of sulfate clearance in patients is independent of this parameter, indicating that sulfate clearance is not merely a reflection of renal function. This exploratory study reveals aberrant sulfate clearance as a potential contributor to CHF pathophysiology, with reduced levels in patients and a positive association with favorable disease outcome. Further research is needed to unravel the nature of its involvement and to determine its potential as a biomarker and target for therapy. NEW & NOTEWORTHY Sulfate clearance is decreased in chronic heart failure patients compared with healthy individuals. Among patients, sulfate clearance is positively associated with favorable disease outcome, i.e., a decreased rehospitalization rate and increased patient survival. Hence, decreased sulfate clearance may be involved in the pathophysiology of heart failure. PMID:27923792

76 FR 17182 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-28

... Activities: Proposed Collection; Comment Request; Generic Clearance for the Collection of Qualitative... Request (Generic ICR): ``Generic Clearance for the Collection of Qualitative Feedback on Agency Service...: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery. Abstract...

48 CFR 945.670-1 - Plant clearance function.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Plant clearance function... MANAGEMENT GOVERNMENT PROPERTY Reporting, Reutilization, and Disposal 945.670-1 Plant clearance function. If the plant clearance function has not been formally delegated to another Federal agency, the...

48 CFR 945.670-1 - Plant clearance function.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Plant clearance function... MANAGEMENT GOVERNMENT PROPERTY Reporting, Reutilization, and Disposal 945.670-1 Plant clearance function. If the plant clearance function has not been formally delegated to another Federal agency, the...

Integrated Turbine Tip Clearance and Gas Turbine Engine Simulation

NASA Technical Reports Server (NTRS)

Chapman, Jeffryes W.; Kratz, Jonathan; Guo, Ten-Huei; Litt, Jonathan

2016-01-01

Gas turbine compressor and turbine blade tip clearance (i.e., the radial distance between the blade tip of an axial compressor or turbine and the containment structure) is a major contributing factor to gas path sealing, and can significantly affect engine efficiency and operational temperature. This paper details the creation of a generic but realistic high pressure turbine tip clearance model that may be used to facilitate active tip clearance control system research. This model uses a first principles approach to approximate thermal and mechanical deformations of the turbine system, taking into account the rotor, shroud, and blade tip components. Validation of the tip clearance model shows that the results are realistic and reflect values found in literature. In addition, this model has been integrated with a gas turbine engine simulation, creating a platform to explore engine performance as tip clearance is adjusted. Results from the integrated model explore the effects of tip clearance on engine operation and highlight advantages of tip clearance management.

A Virtual Reality avatar interaction (VRai) platform to assess residual executive dysfunction in active military personnel with previous mild traumatic brain injury: proof of concept.

PubMed

Robitaille, Nicolas; Jackson, Philip L; Hébert, Luc J; Mercier, Catherine; Bouyer, Laurent J; Fecteau, Shirley; Richards, Carol L; McFadyen, Bradford J

2017-10-01

This proof of concept study tested the ability of a dual task walking protocol using a recently developed avatar-based virtual reality (VR) platform to detect differences between military personnel post mild traumatic brain injury (mTBI) and healthy controls. The VR platform coordinated motion capture, an interaction and rendering system, and a projection system to present first (participant-controlled) and third person avatars within the context of a specific military patrol scene. A divided attention task was also added. A healthy control group was compared to a group with previous mTBI (both groups comprised of six military personnel) and a repeated measures ANOVA tested for differences between conditions and groups based on recognition errors, walking speed and fluidity and obstacle clearance. The VR platform was well tolerated by both groups. Walking fluidity was degraded for the control group within the more complex navigational dual tasking involving avatars, and appeared greatest in the dual tasking with the interacting avatar. This navigational behaviour was not seen in the mTBI group. The present findings show proof of concept for using avatars, particularly more interactive avatars, to expose differences in executive functioning when applying context-specific protocols (here for the military). Implications for rehabilitation Virtual reality provides a means to control context-specific factors for assessment and intervention. Adding human interaction and agency through avatars increases the ecologic nature of the virtual environment. Avatars in the present application of the Virtual Reality avatar interaction platform appear to provide a better ability to reveal differences between trained, military personal with and without mTBI.

76 FR 39893 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-07

...; Comment Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery... (Generic ICR): ``Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery.... SUPPLEMENTARY INFORMATION: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service...

76 FR 19359 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-07

... Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery AGENCY... Information Collection Request (Generic ICR): ``Generic Clearance for the Collection of Qualitative Feedback...: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery. Abstract...

45 CFR 675.3 - Medical clearance criteria.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 3 2014-10-01 2014-10-01 false Medical clearance criteria. 675.3 Section 675.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION MEDICAL CLEARANCE PROCESS FOR DEPLOYMENT TO ANTARCTICA § 675.3 Medical clearance criteria. (a) The USAP shall...

45 CFR 675.3 - Medical clearance criteria.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 3 2013-10-01 2013-10-01 false Medical clearance criteria. 675.3 Section 675.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION MEDICAL CLEARANCE PROCESS FOR DEPLOYMENT TO ANTARCTICA § 675.3 Medical clearance criteria. (a) The USAP shall...

76 FR 59379 - Proposed Information Collection; Comment Request; Generic Clearance for Research in Development...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-26

...-XXXX. Type of Review: Generic Clearance Request. Title: Generic Clearance for Research in Development..., filing of petitions and applications and agency #0;statements of organization and functions are examples... Proposed Information Collection; Comment Request; Generic Clearance for Research in Development of...

45 CFR 675.3 - Medical clearance criteria.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 3 2011-10-01 2011-10-01 false Medical clearance criteria. 675.3 Section 675.3 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION MEDICAL CLEARANCE PROCESS FOR DEPLOYMENT TO ANTARCTICA § 675.3 Medical clearance criteria. (a) The USAP shall...

Space assets for demining assistance

NASA Astrophysics Data System (ADS)

Kruijff, Michiel; Eriksson, Daniel; Bouvet, Thomas; Griffiths, Alexander; Craig, Matthew; Sahli, Hichem; González-Rosón, Fernando Valcarce; Willekens, Philippe; Ginati, Amnon

2013-02-01

Populations emerging from armed conflicts often remain threatened by landmines and explosive remnants of war. The international mine action community is concerned with the relief of this threat. The Space Assets for Demining Assistance (SADA) undertaking is a set of activities that aim at developing new services to improve the socio-economic impact of mine action activities, primarily focused on the release of land thought to be contaminated, a process described as land release. SADA was originally initiated by the International Astronautical Federation (IAF). It has been implemented under the Integrated Applications Promotion (IAP) program of the European Space Agency (ESA). Land release in mine action is the process whereby the demining community identifies, surveys and prioritizes suspected hazardous areas for more detailed investigation, which eventually results in the clearance of landmines and other explosives, thereby releasing land to the local population. SADA has a broad scope, covering activities, such as planning (risk and impact analysis, prioritization, and resource management), field operations and reporting. SADA services are developed in two phases: feasibility studies followed by demonstration projects. Three parallel feasibility studies have been performed. They aimed at defining an integrated set of space enabled services to support the land release process in mine action, and at analyzing their added value, viability and sustainability. The needs of the mine action sector have been assessed and the potential contribution of space assets has been identified. Support services have been formulated. To test their fieldability, proofs of concept involving mine action end users in various operational field settings have been performed by each of the study teams. The economic viability has also been assessed. Whenever relevant and cost-effective, SADA aims at integrating Earth observation data, GNSS navigation and SatCom technologies with existing mine action tools and procedures, as well as with novel aerial survey technologies. Such conformity with existing user processes, as well as available budgets and appropriateness of technology based solutions given the field level operational setting are important conditions for success. The studies have demonstrated that Earth observation data, satellite navigation solutions and in some cases, satellite communication, indeed can provide added value to mine action activities if properly tailored based on close user interaction and provided through a suitable channel. Such added value for example includes easy and sustained access to Earth observation data for general purpose mapping, land use assessment for post-release progress reporting, and multi-source data fusion algorithms to help quantify risks and socio-economic impact for prioritization and planning purposes. The environment and boundaries of a hazardous area can also be better specified to support the land release process including detailed survey and clearance operations. Satellite communication can help to provide relevant data to remote locations, but is not regarded as strongly user driven. Finally, satellite navigation can support more precise non-technical surveys, as well as aerial observation with small planes or hand-launched UAV's. To ensure the activity is genuinely user driven, the Geneva International Center for Humanitarian Demining (GICHD) plays an important role as ESA's external advisor. ESA is furthermore supported by a representative field operator, the Swiss Foundation of Mine Action (FSD), providing ESA with a direct connection to the field level end users. Specifically FSD has provided a shared user needs baseline to the three study teams. To ensure solutions meet with end user requirements, the study teams themselves include mine action representatives and have interacted closely with their pre-existing and newly established contacts within the mine action community.

Long-term clearance from small airways in patients with cystic fibrosis.

PubMed

Lindström, M; Camner, P; Falk, R; Hjelte, L; Philipson, K; Svartengren, M

2005-02-01

Impaired mucociliary clearance is a hallmark of cystic fibrosis (CF). Early morphological changes first appear in the small airways. Lung clearance was investigated in 11 young CF adults with mild-to-moderate lung disease using a method depositing particles mainly in the small airways. Radiolabelled Teflon particles (6 microm) were inhaled with an extremely slow inhalation flow, 0.05 L x s(-1). Lung retention was measured immediately following inhalations and, on four occasions up to 21 days. The results were compared with data from healthy subjects. The lung retention at 24 h in % of deposition was 67% (95% confidence interval 58-76) in the CF patients, compared to 48% (42-53) in the healthy subjects. Clearance on days 1-7 was larger in the CF patients, 22% (15-29) compared to the healthy subjects, 14% (12-16). No difference was observed between the CF patients and the healthy subjects in the slow clearance phase at day 7 to day 21, representing small airway clearance. Impaired mucociliary clearance in CF patients results in increased 24-h retention and a prolonged rapid clearance phase. The results of the study do not support the current authors' hypothesis that clearance from small airways is slower in cystic fibrosis patients compared to healthy subjects. Furthermore, the data suggest that mucociliary transport is not the dominant clearance mechanism in small airways.

The effects of selected air pollutants on clearance of titanic oxide particles from the lungs of rats.

PubMed

Ferin, J; Leach, L J

1975-09-01

A procedure utilizing the lung clearance kinetics of titanic oxide (TiO2) particles was used to determine the effects of inhaled sulphur dioxide (SO2) and nitrogen oxides (NO x) on particle clearance. The procedure is reproducible and mainly tests clearance mechanisms involving alveolar macrophages and the mucociliary transport system at the alveolobronchial clearance pathway. At low SO2 or NOx exposures enhanced particle clearance was observed. Lung clearance was depressed at 15 and 24 ppm of NO2 after 22 exposures as well as at 20 ppm of SO2 after 11 exposures, and also at 1 ppm of SO2 after 25 exposures. Dose-response curves for the SO2 and NOx exposures showed differences explainable by the routes by which these gases reach the alveolar macrophages.

Study of blade clearance effects on centrifugal pumps

NASA Technical Reports Server (NTRS)

Hoshide, R. K.; Nielson, C. E.

1972-01-01

A program of analysis, design, fabrication, and testing has been conducted to develop and experimentally verify analytical models to predict the effects of impeller blade clearance on centrifugal pumps. The effect of tip clearance on pump efficiency, and the relationship between the head coefficient and torque loss with tip clearance was established. Analysis were performed to determine the cost variation in design, manufacture, and test that would occur between unshrouded and shrouded impellers. An impeller, representative of typical rocket engine impellers, was modified by removing its front shroud to permit variation of its blade clearances. It was tested in water with special instrumentation to provide measurements of blade surface pressures during operation. Pump performance data were obtained from tests at various impeller tip clearances. Blade pressure data were obtained at the nominal tip clearance. Comparisons of predicted and measured data are given.

Modeling Immunization To Infliximab in Children With Crohn's Disease Using Population Pharmacokinetics: A Pilot Study.

PubMed

Petitcollin, Antoine; Leuret, Oriane; Tron, Camille; Lemaitre, Florian; Verdier, Marie-Clémence; Paintaud, Gilles; Bouguen, Guillaume; Willot, Stéphanie; Bellissant, Eric; Ternant, David

2018-05-18

Antidrug antibodies (ADAs) dramatically increase infliximab clearance and are responsible for underexposure to the drug, leading to treatment failure. This pilot study aimed at developing a population pharmacokinetic model to detect and describe an early increase in infliximab clearance due to ADA. Twenty children with Crohn's disease (CD) were followed for 1 year or until treatment failure. Infliximab trough concentration, ADA, C-reactive protein (CRP), and Paediatric Crohn's Disease Activity Index (PCDAI) were recorded at each visit. A time-varying clearance population pharmacokinetic model was built to detect and describe an increase in infliximab clearance, independent from ADA testing. Factors associated with clearance variation and the relationships between infliximab concentrations, clearance variation, and clinical response were investigated. The model detected important increases in clearance in 4 patients. These patients had suboptimal early response, with higher mean PCDAI (P = 0.0086) and CRP (P = 0.028) compared with other patients. Two of them had detectable ADA. Clearance increase as described by the model and lower infliximab trough concentration at week 2 were associated with poorer outcomes in a multivariate Cox model (P = 0.001 and P = 0.0048, respectively). Being able to detect an increase in infliximab clearance, this model could allow the early detection of immunization to infliximab and therefore could help with dose adjustment in patients with CD. Moreover, the results suggest that clearance variations could be used as a predictive marker of clinical response. These findings need to be confirmed in a larger cohort, however, and predictive factors of clearance increase have to be investigated.

Application of a Physiologically Based Pharmacokinetic Model to Assess Propofol Hepatic and Renal Glucuronidation in Isolation: Utility of In Vitro and In Vivo Data

PubMed Central

Gill, Katherine L.; Gertz, Michael; Houston, J. Brian

2013-01-01

A physiologically based pharmacokinetic (PBPK) modeling approach was used to assess the prediction accuracy of propofol hepatic and extrahepatic metabolic clearance and to address previously reported underprediction of in vivo clearance based on static in vitro–in vivo extrapolation methods. The predictive capacity of propofol intrinsic clearance data (CLint) obtained in human hepatocytes and liver and kidney microsomes was assessed using the PBPK model developed in MATLAB software. Microsomal data obtained by both substrate depletion and metabolite formation methods and in the presence of 2% bovine serum albumin were considered in the analysis. Incorporation of hepatic and renal in vitro metabolic clearance in the PBPK model resulted in underprediction of propofol clearance regardless of the source of in vitro data; the predicted value did not exceed 35% of the observed clearance. Subsequently, propofol clinical data from three dose levels in intact patients and anhepatic subjects were used for the optimization of hepatic and renal CLint in a simultaneous fitting routine. Optimization process highlighted that renal glucuronidation clearance was underpredicted to a greater extent than liver clearance, requiring empirical scaling factors of 17 and 9, respectively. The use of optimized clearance parameters predicted hepatic and renal extraction ratios within 20% of the observed values, reported in an additional independent clinical study. This study highlights the complexity involved in assessing the contribution of extrahepatic clearance mechanisms and illustrates the application of PBPK modeling, in conjunction with clinical data, to assess prediction of clearance from in vitro data for each tissue individually. PMID:23303442

33 CFR 117.415 - Green River.

Code of Federal Regulations, 2010 CFR

2010-07-01

... vertical clearance beneath the draw. When vertical clearance is more than 40 feet, at least four hours... clearance. When the vertical clearance is more than 40 feet, at least four hours notice shall be given... vessel will return within four hours, the drawtender shall remain on duty until the vessel returns but is...

76 FR 55078 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-06

...; Comment Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery...): ``Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery'' to OMB for.... SUPPLEMENTARY INFORMATION: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service...

76 FR 10626 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-25

... Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery AGENCY... Clearance for the Collection of Qualitative Feedback on Agency Service Delivery'' to OMB for approval under...: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery. Abstract...

24 CFR 3285.305 - Clearance under homes.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Clearance under homes. 3285.305... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Foundations § 3285.305 Clearance under homes. A minimum clearance of 12 inches must be maintained between the lowest member of the main frame...

24 CFR 3285.305 - Clearance under homes.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Clearance under homes. 3285.305... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Foundations § 3285.305 Clearance under homes. A minimum clearance of 12 inches must be maintained between the lowest member of the main frame...

24 CFR 3285.305 - Clearance under homes.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Clearance under homes. 3285.305... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Foundations § 3285.305 Clearance under homes. A minimum clearance of 12 inches must be maintained between the lowest member of the main frame...

24 CFR 3285.305 - Clearance under homes.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Clearance under homes. 3285.305... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Foundations § 3285.305 Clearance under homes. A minimum clearance of 12 inches must be maintained between the lowest member of the main frame...

24 CFR 3285.305 - Clearance under homes.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Clearance under homes. 3285.305... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Foundations § 3285.305 Clearance under homes. A minimum clearance of 12 inches must be maintained between the lowest member of the main frame...

22 CFR 16.6 - Security clearances.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Security clearances. 16.6 Section 16.6 Foreign Relations DEPARTMENT OF STATE PERSONNEL FOREIGN SERVICE GRIEVANCE SYSTEM § 16.6 Security clearances. The agencies shall use their best endeavors to expedite security clearances whenever necessary to ensure a fair...

22 CFR 16.6 - Security clearances.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Security clearances. 16.6 Section 16.6 Foreign Relations DEPARTMENT OF STATE PERSONNEL FOREIGN SERVICE GRIEVANCE SYSTEM § 16.6 Security clearances. The agencies shall use their best endeavors to expedite security clearances whenever necessary to ensure a fair...

22 CFR 16.6 - Security clearances.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Security clearances. 16.6 Section 16.6 Foreign Relations DEPARTMENT OF STATE PERSONNEL FOREIGN SERVICE GRIEVANCE SYSTEM § 16.6 Security clearances. The agencies shall use their best endeavors to expedite security clearances whenever necessary to ensure a fair...

10 CFR 1016.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... authorizations or clearances will be defined. (1) “Q” access authorizations or clearances are based upon full... quantities as required in the performance of duties. (2) “Q(X)” access authorizations or clearances are based...” access authorizations or clearances are based upon National Agency Checks and Inquiries (NACI) for...

10 CFR 1016.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... authorizations or clearances will be defined. (1) “Q” access authorizations or clearances are based upon full... quantities as required in the performance of duties. (2) “Q(X)” access authorizations or clearances are based...” access authorizations or clearances are based upon National Agency Checks and Inquiries (NACI) for...

30 CFR 56.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Warning devices for restricted clearances. 56... Loading and Dumping Sites § 56.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 57.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Warning devices for restricted clearances. 57... Loading and Dumping Sites § 57.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 56.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Warning devices for restricted clearances. 56... Loading and Dumping Sites § 56.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 57.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Warning devices for restricted clearances. 57... Loading and Dumping Sites § 57.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 57.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Warning devices for restricted clearances. 57... Loading and Dumping Sites § 57.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 57.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Warning devices for restricted clearances. 57... Loading and Dumping Sites § 57.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 56.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Warning devices for restricted clearances. 56... Loading and Dumping Sites § 56.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 56.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Warning devices for restricted clearances. 56... Loading and Dumping Sites § 56.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 57.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Warning devices for restricted clearances. 57... Loading and Dumping Sites § 57.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

30 CFR 56.9306 - Warning devices for restricted clearances.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Warning devices for restricted clearances. 56... Loading and Dumping Sites § 56.9306 Warning devices for restricted clearances. Where restricted clearance creates a hazard to persons on mobile equipment, warning devices shall be installed in advance of the...

14 CFR 1260.63 - Customs clearance and visas.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Customs clearance and visas. 1260.63 Section 1260.63 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.63 Customs clearance and visas. Customs Clearance and Visas (For...

14 CFR 1260.63 - Customs clearance and visas.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Customs clearance and visas. 1260.63 Section 1260.63 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.63 Customs clearance and visas. Customs Clearance and Visas (For...

14 CFR 1260.63 - Customs clearance and visas.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Customs clearance and visas. 1260.63 Section 1260.63 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.63 Customs clearance and visas. Customs Clearance and Visas (For...

14 CFR 1260.63 - Customs clearance and visas.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Customs clearance and visas. 1260.63 Section 1260.63 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.63 Customs clearance and visas. Customs Clearance and Visas (For...

48 CFR 2452.237-75 - Clearance of contractor personnel.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Clearance of contractor... Clauses 2452.237-75 Clearance of contractor personnel. As prescribed in 2437.110(e), insert the following clause in solicitations and contracts. Clearance of Contractor Personnel (OCT 1999) (a) General. This...

46 CFR 56.75-10 - Joint clearance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Joint clearance. 56.75-10 Section 56.75-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Brazing § 56.75-10 Joint clearance. (a) The clearance between surfaces to be joined shall be no...

Fuel conservation through active control of rotor clearances

NASA Technical Reports Server (NTRS)

Beitler, R. S.; Saunders, A. A.; Wanger, R. P.

1980-01-01

Under the NASA-sponsored Energy Efficient Engine (EEE) Project, technology is being developed which will significantly reduce the fuel consumption of turbofan engines for subsonic transport aircraft. One technology concept being pursued is active control of rotor tip clearances. Attention is given to rotor tip clearance considerations and an overview of preliminary study results as well as the General Electric EEE clearance control approach is presented. Finally, potential fuel savings with active control of rotor clearances for a typical EEE mission are predicted.

Flight Deck Surface Trajectory-based Operations (STBO): Results of Piloted Simulations and Implications for Concepts of Operation (ConOps)

NASA Technical Reports Server (NTRS)

Foyle, David C.; Hooey, Becky L.; Bakowski, Deborah L.

2013-01-01

The results offour piloted medium-fidelity simulations investigating flight deck surface trajectory-based operations (STBO) will be reviewed. In these flight deck STBO simulations, commercial transport pilots were given taxi clearances with time and/or speed components and required to taxi to the departing runway or an intermediate traffic intersection. Under a variety of concept of operations (ConOps) and flight deck information conditions, pilots' ability to taxi in compliance with the required time of arrival (RTA) at the designated airport location was measured. ConOps and flight deck information conditions explored included: Availability of taxi clearance speed and elapsed time information; Intermediate RTAs at intermediate time constraint points (e.g., intersection traffic flow points); STBO taxi clearances via ATC voice speed commands or datal ink; and, Availability of flight deck display algorithms to reduce STBO RTA error. Flight Deck Implications. Pilot RTA conformance for STBO clearances, in the form of ATC taxi clearances with associated speed requirements, was found to be relatively poor, unless the pilot is required to follow a precise speed and acceleration/deceleration profile. However, following such a precise speed profile results in inordinate head-down tracking of current ground speed, leading to potentially unsafe operations. Mitigating these results, and providing good taxi RTA performance without the associated safety issues, is a flight deck avionics or electronic flight bag (EFB) solution. Such a solution enables pilots to meet the taxi route RTA without moment-by-moment tracking of ground speed. An avionics or EFB "error-nulling" algorithm allows the pilot to view the STBO information when the pilot determines it is necessary and when workload alloys, thus enabling the pilot to spread his/her attention appropriately and strategically on aircraft separation airport navigation, and the many other flight deck tasks concurrently required. Surface Traffic Management (STM) System Implications. The data indicate a number of implications regarding specific parameters for ATC/STM algorithm development. Pilots have a tendency to arrive at RTA points early with slow required speeds, on time for moderate speeds, and late with faster required speeds. This implies that ATC/STM algorithms should operate with middle-range speeds, similar to that of non-STBO taxi performance. Route length has a related effect: Long taxi routes increase the earliness with slow speeds and the lateness with faster speeds. This is likely due to the" open-loop" nature of the task in which the speed error compounds over a longer time with longer routes. Results showed that this may be mitigated by imposing a small number oftime constraint points each with their own RTAs effectively tuming a long route into a series of shorter routes - and thus improving RTA performance. STBO ConOps Implications. Most important is the impact that these data have for NextGen STM system ConOps development. The results of these experiments imply that it is not reasonable to expect pilots to taxi under a "Full STBO" ConOps in which pilots are expected to be at a predictable (x,y) airport location for every time (t). An STBO ConOps with a small number of intermediate time constraint points and the departing runway, however, is feasible, but only with flight deck equipage enabling the use of a display similar to the "error-nulling algorithm/display" tested.

Effect of isolated hepatic ischemia on organic anion clearance and oxidative metabolism.

PubMed

Minard, G; Bynoe, R; Wood, G C; Fabian, T C; Croce, M; Kudsk, K A

1992-04-01

Hepatic failure is frequently seen following severe hemorrhagic shock, sepsis, and trauma. Clearance of various drugs has been used to evaluate hepatocellular dysfunction, including indocyanine green (ICG), an organic anionic dye that is transported similarly to bilirubin, and antipyrine (AP), a marker of oxidative phosphorylation. Previous investigators have noted a decrease in ICG excretion following systemic hemorrhage. The effect of isolated hepatic ischemia on the clearances of ICG and AP was studied in 16 pigs after 90 minutes of vascular occlusion to the liver. Antipyrine clearance decreased almost 50% from baseline values at 24 and 72 hours after the ischemia procedure, indicating a significant depression in the cytochrome P-450 system. On the other hand, ICG clearance did not change significantly. In conclusion, ICG clearance is not depressed after isolated hepatic ischemia in pigs. Changes in organic anion clearance after systemic hemorrhage may be because of release of toxic products from ischemic peripheral tissue.

48 CFR 245.7101-4 - DD Form 1640, Request for Plant Clearance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false DD Form 1640, Request for Plant Clearance. 245.7101-4 Section 245.7101-4 Federal Acquisition Regulations System DEFENSE... Forms 245.7101-4 DD Form 1640, Request for Plant Clearance. Use to request plant clearance assistance or...

49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

49 CFR 236.22 - Semaphore signal arm; clearance to other objects.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Semaphore signal arm; clearance to other objects... Rules and Instructions: All Systems Roadway Signals and Cab Signals § 236.22 Semaphore signal arm; clearance to other objects. At least one-half inch clearance shall be provided between semaphore signal arm...

14 CFR § 1260.63 - Customs clearance and visas.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Customs clearance and visas. § 1260.63... COOPERATIVE AGREEMENTS General Special Conditions § 1260.63 Customs clearance and visas. Customs Clearance and Visas (For grants or cooperative agreements with foreign organizations, this clause will be developed on...

Analysis of foot clearance in firefighters during ascent and descent of stairs.

PubMed

Kesler, Richard M; Horn, Gavin P; Rosengren, Karl S; Hsiao-Wecksler, Elizabeth T

2016-01-01

Slips, trips, and falls are a leading cause of injury to firefighters with many injuries occurring while traversing stairs, possibly exaggerated by acute fatigue from firefighting activities and/or asymmetric load carriage. This study examined the effects that fatigue, induced by simulated firefighting activities, and hose load carriage have on foot clearance while traversing stairs. Landing and passing foot clearances for each stair during ascent and descent of a short staircase were investigated. Clearances decreased significantly (p < 0.05) post-exercise for nine of 12 ascent parameters and increased for two of eight descent parameters. Load carriage resulted in significantly decreased (p < 0.05) clearance over three ascent parameters, and one increase during descent. Decreased clearances during ascent caused by fatigue or load carriage may result in an increased trip risk. Increased clearances during descent may suggest use of a compensation strategy to ensure stair clearance or an increased risk of over-stepping during descent. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Should we consider steps with variable height for a safer stair negotiation in older adults?

PubMed

Kunzler, Marcos R; da Rocha, Emmanuel S; Dos Santos, Christielen S; Ceccon, Fernando G; Priario, Liver A; Carpes, Felipe P

2018-01-01

Effects of exercise on foot clearances are important. In older adults variations in foot clearances during walking may lead to a fall, but there is a lack of information concerning stair negotiation in older adults. Whether a condition of post exercise changes foot clearances between steps of a staircase in older adults still unknown. To determine differences in clearances when older adults negotiate different steps of a staircase before and after a session of aerobic exercise. Kinematics data from 30 older adults were acquired and the toe and heel clearances were determined for each step. Clearances were compared between the steps. Smaller clearances were found at the highest step during ascending and descending, which was not changed by exercise. Smaller clearances suggest higher risk of tripping at the top of the staircase, regardless of exercise. A smaller step at the top of a short flight of stairs could reduce chances of tripping in older adults. It suggests that steps with variable height could make stair negotiation safer in older adults. This hypothesis should be tested in further studies.

Radioaerosol lung clearance in patients with active pulmonary sarcoidosis

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

Jacobs, M.P.; Baughman, R.P.; Hughes, J.

1985-05-01

Pulmonary radioaerosol clearance rate of /sup 99m/Tc diethylenetriamine pentacetate (DTPA) in 14 patients with untreated sarcoidosis was compared with /sup 67/Ga lung scan and increased lymphocytes in the bronchoalveolar lavage (BAL) fluid. Nine healthy nonsmoking subjects had a mean DTPA clearance rate of 1.18%/min (range, 0.54 to 1.60%/min). Eight of 14 patients with sarcoidosis had clearance rates greater than 1.60%/min. Of those 8 patients with abnormal DTPA clearance, 4 had positive gallium scans, 4 had more than 17% lymphocytes in the BAL fluid, and 3 had both tests positive. To study the cause of abnormal DTPA clearance, 23 subjects (includingmore » 3 normal controls, all 14 patients with sarcoidosis, and 6 patients with localized disease on chest roentgenogram) underwent both DTPA clearance studies and BAL for quantitation of the amount of albumin in lung fluid. There was a positive correlation between the rate of DTPA clearance and the albumin concentration in lung fluid (r = 0.87, p less than 0.01).« less

Lactate clearance cut off for early mortality prediction in adult sepsis and septic shock patients

NASA Astrophysics Data System (ADS)

Sinto, R.; Widodo, D.; Pohan, H. T.

2018-03-01

Previous lactate clearance cut off for early mortality prediction in sepsis and septic shock patient was determined by consensus from small sample size-study. We investigated the best lactate clearance cut off and its ability to predict early mortality in sepsis and septic shock patients. This cohort study was conducted in Intensive Care Unit of CiptoMangunkusumo Hospital in 2013. Patients’ lactate clearance and eight other resuscitationendpoints were recorded, and theoutcome was observed during the first 120 hours. The clearance cut off was determined using receiver operating characteristic (ROC) analysis, and its ability was investigated with Cox’s proportional hazard regression analysis using other resuscitation endpoints as confounders. Total of 268 subjects was included, of whom 70 (26.11%) subjects died within the first 120 hours. The area under ROC of lactate clearance to predict early mortality was 0.78 (95% % confidence interval [CI] 0.71-0.84) with best cut off was <7.5% (sensitivity and specificity 88.99% and 81.4% respectively). Compared with group achieving lactate clearance target, group not achieving lactate clearance target had to increase early mortality risk (adjusted hazard ratio 13.42; 95%CI 7.19-25.07). In conclusion, the best lactate clearance cut off as anearly mortality predictor in sepsis and septic shock patients is 7.5%.

Clearance systems in the brain-implications for Alzheimer disease.

PubMed

Tarasoff-Conway, Jenna M; Carare, Roxana O; Osorio, Ricardo S; Glodzik, Lidia; Butler, Tracy; Fieremans, Els; Axel, Leon; Rusinek, Henry; Nicholson, Charles; Zlokovic, Berislav V; Frangione, Blas; Blennow, Kaj; Ménard, Joël; Zetterberg, Henrik; Wisniewski, Thomas; de Leon, Mony J

2015-08-01

Accumulation of toxic protein aggregates-amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles-is the pathological hallmark of Alzheimer disease (AD). Aβ accumulation has been hypothesized to result from an imbalance between Aβ production and clearance; indeed, Aβ clearance seems to be impaired in both early and late forms of AD. To develop efficient strategies to slow down or halt AD, it is critical to understand how Aβ is cleared from the brain. Extracellular Aβ deposits can be removed from the brain by various clearance systems, most importantly, transport across the blood-brain barrier. Findings from the past few years suggest that astroglial-mediated interstitial fluid (ISF) bulk flow, known as the glymphatic system, might contribute to a larger portion of extracellular Aβ (eAβ) clearance than previously thought. The meningeal lymphatic vessels, discovered in 2015, might provide another clearance route. Because these clearance systems act together to drive eAβ from the brain, any alteration to their function could contribute to AD. An understanding of Aβ clearance might provide strategies to reduce excess Aβ deposits and delay, or even prevent, disease onset. In this Review, we describe the clearance systems of the brain as they relate to proteins implicated in AD pathology, with the main focus on Aβ.

Lack of effect of non-steroid antiinflammatory drugs on lithium clearance and on delivery of tubular fluid to the loop of Henle in rats.

PubMed

Lassen, E; Thomsen, K; Sørensen, S S; Pedersen, E B

1986-11-01

This paper examines a possible interaction between non-steroid antiinflammatory drugs (NSAI drugs) and renal lithium clearance in conscious, unoperated rats with diabetes insipidus (Brattleboro strain) and ordinary Wistar rats. The drugs were given with the food for 5 days before clearance determinations in the following daily doses per kg body weight: acetylsalicyclic acid 115 mg/kg, phenylbutazone 20 mg/kg, indomethacin 5 mg/kg, and penicillamine 65 mg/kg. None of the drugs affected the lithium clearance. Also urine flow, sodium clearance, potassium clearance, and prostaglandin E2 excretion remained unaffected by the treatments. The results suggest that a continued lowering of lithium clearance cannot be produced, at least not by administration of the drugs with the food. Since lithium clearance is a quantitative measure of the delivery of tubular fluid from the proximal tubules to the loop of Henle, the results also suggest that chronic administration of NSAI drugs does not influence delivery from the proximal tubules in rats. The lowering of lithium clearance observed by others after administration of the drugs by injection or by gastric tube may have been transient, lasting only for a short period after each administration.

Clearance systems in the brain—implications for Alzheimer disease

PubMed Central

Tarasoff-Conway, Jenna M.; Carare, Roxana O.; Osorio, Ricardo S.; Glodzik, Lidia; Butler, Tracy; Fieremans, Els; Axel, Leon; Rusinek, Henry; Nicholson, Charles; Zlokovic, Berislav V.; Frangione, Blas; Blennow, Kaj; Ménard, Joël; Zetterberg, Henrik; Wisniewski, Thomas; de Leon, Mony J.

2015-01-01

Accumulation of toxic protein aggregates—amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles—is the pathological hallmark of Alzheimer disease (AD). Aβ accumulation has been hypothesized to result from an imbalance between Aβ production and clearance; indeed, Aβ clearance seems to be impaired in both early and late forms of AD. To develop efficient strategies to slow down or halt AD, it is critical to understand how Aβ is cleared from the brain. Extracellular Aβ deposits can be removed from the brain by various clearance systems, most importantly, transport across the blood–brain barrier. Findings from the past few years suggest that astroglial-mediated interstitial fluid (ISF) bulk flow, known as the glymphatic system, might contribute to a larger portion of extracellular Aβ (eAβ) clearance than previously thought. The meningeal lymphatic vessels, discovered in 2015, might provide another clearance route. Because these clearance systems act together to drive eAβ from the brain, any alteration to their function could contribute to AD. An understanding of Aβ clearance might provide strategies to reduce excess Aβ deposits and delay, or even prevent, disease onset. In this Review, we describe the clearance systems of the brain as they relate to proteins implicated in AD pathology, with the main focus on Aβ. PMID:26195256

Estradiol and weight are covariates of paracetamol clearance in young women.

PubMed

Beleyn, B; Vermeersch, S; Kulo, A; Smits, A; Verbesselt, R; de Hoon, J N; Van Calsteren, K; Allegaert, K

2014-01-01

Paracetamol clearance differs between pregnant and non-pregnant women and between women with or without specific oral contraceptives (OCs). However, an association between female sex hormones and paracetamol clearance has never been explored. In total, 49 women at delivery, 8 female control subjects without OC use, historical data of 14 women taking OCs, and 15 postpartum observations with and without OCs were pooled to explore covariates of paracetamol clearance. All received a single intravenous 2-gram paracetamol dose, and blood samples were collected up to 6 h after dosing. High-performance liquid chromatography was used to quantify paracetamol. The area under the curve to time infinity (AUC0-∞) was determined and clearance (l/h·m(2)) was calculated by dose/ AUC0-∞. In addition, estradiol and progesterone were quantified by ELISA with electro-chemiluminescence. Median paracetamol clearance at delivery was significantly higher when compared to postpartum or non-pregnant women (11.9 vs. 6.42 and 8.4 l/h·m(2), at least p < 0.05), while an association between paracetamol clearance and estradiol was observed (R = 0.494, p < 0.0001). In non-pregnant subjects, there was no impact of OC exposure on paracetamol clearance. Multiple regression revealed a linear association (Radj = 0.41, p < 0.001) between paracetamol clearance and weight (p = 0.0462) and estradiol (p < 0.0001). Estradiol and weight in part explain the variation in paracetamol clearance in young women. © 2014 S. Karger AG, Basel.

The Role of Radial Clearance on the Performance of Foil Air Bearings

NASA Technical Reports Server (NTRS)

Radil, Kevin; Howard, Samuel; Dykas, Brian

2002-01-01

Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation III foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS304 coated journal operating at 30,000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings. The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20 percent decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.

Age-Related Decline in Brain and Hepatic Clearance of Amyloid-Beta is Rectified by the Cholinesterase Inhibitors Donepezil and Rivastigmine in Rats.

PubMed

Mohamed, Loqman A; Qosa, Hisham; Kaddoumi, Amal

2015-05-20

In Alzheimer's disease (AD), accumulation of brain amyloid-β (Aβ) depends on imbalance between production and clearance of Aβ. Several pathways for Aβ clearance have been reported including transport across the blood-brain barrier (BBB) and hepatic clearance. The incidence of AD increases with age and failure of Aβ clearance correlates with AD. The cholinesterase inhibitors (ChEIs) donepezil and rivastigmine are used to ease the symptoms of dementia associated with AD. Besides, both drugs have been reported to provide neuroprotective and disease-modifying effects. Here, we investigated the effect of ChEIs on age-related reduced Aβ clearance. Findings from in vitro and in vivo studies demonstrated donepezil and rivastigmine to enhance (125)I-Aβ40 clearance. Also, the increase in brain and hepatic clearance of (125)I-Aβ40 was more pronounced in aged compared to young rats, and was associated with significant reduction in brain Aβ endogenous levels determined by ELISA. Furthermore, the enhanced clearance was concomitant with up-regulation in the expression of Aβ major transport proteins P-glycoprotein and LRP1. Collectively, our findings that donepezil and rivastigmine enhance Aβ clearance across the BBB and liver are novel and introduce an additional mechanism by which both drugs could affect AD pathology. Thus, optimizing their clinical use could help future drug development by providing new drug targets and possible mechanisms involved in AD pathology.

Hepatobiliary Clearance Prediction: Species Scaling From Monkey, Dog, and Rat, and In Vitro-In Vivo Extrapolation of Sandwich-Cultured Human Hepatocytes Using 17 Drugs.

PubMed

Kimoto, Emi; Bi, Yi-An; Kosa, Rachel E; Tremaine, Larry M; Varma, Manthena V S

2017-09-01

Hepatobiliary elimination can be a major clearance pathway dictating the pharmacokinetics of drugs. Here, we first compared the dose eliminated in bile in preclinical species (monkey, dog, and rat) with that in human and further evaluated single-species scaling (SSS) to predict human hepatobiliary clearance. Six compounds dosed in bile duct-cannulated (BDC) monkeys showed biliary excretion comparable to human; and the SSS of hepatobiliary clearance with plasma fraction unbound correction yielded reasonable predictions (within 3-fold). Although dog SSS also showed reasonable predictions, rat overpredicted hepatobiliary clearance for 13 of 24 compounds. Second, we evaluated the translatability of in vitro sandwich-cultured human hepatocytes (SCHHs) to predict human hepatobiliary clearance for 17 drugs. For drugs with no significant active uptake in SCHH studies (i.e., with or without rifamycin SV), measured intrinsic biliary clearance was directly scalable with good predictability (absolute average fold error [AAFE] = 1.6). Drugs showing significant active uptake in SCHH, however, showed improved predictability when scaled based on extended clearance term (AAFE = 2.0), which incorporated sinusoidal uptake along with a global scaling factor for active uptake and the canalicular efflux clearance. In conclusion, SCHH is a useful tool to predict human hepatobiliary clearance, whereas BDC monkey model may provide further confidence in the prospective predictions. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

A model of clearance rate regulation in mussels

NASA Astrophysics Data System (ADS)

Fréchette, Marcel

2012-10-01

Clearance rate regulation has been modelled as an instantaneous response to food availability, independent of the internal state of the animals. This view is incompatible with latent effects during ontogeny and phenotypic flexibility in clearance rate. Internal-state regulation of clearance rate is required to account for these patterns. Here I develop a model of internal-state based regulation of clearance rate. External factors such as suspended sediments are included in the model. To assess the relative merits of instantaneous regulation and internal-state regulation, I modelled blue mussel clearance rate and growth using a DEB model. In the usual standard feeding module, feeding is governed by a Holling's Type II response to food concentration. In the internal-state feeding module, gill ciliary activity and thus clearance rate are driven by internal reserve level. Factors such as suspended sediments were not included in the simulations. The two feeding modules were compared on the basis of their ability to capture the impact of latent effects, of environmental heterogeneity in food abundance and of physiological flexibility on clearance rate and individual growth. The Holling feeding module was unable to capture the effect of any of these sources of variability. In contrast, the internal-state feeding module did so without any modification or ad hoc calibration. Latent effects, however, appeared transient. With simple annual variability in temperature and food concentration, the relationship between clearance rate and food availability predicted by the internal-state feeding module was quite similar to that observed in Norwegian fjords. I conclude that in contrast with the usual Holling feeding module, internal-state regulation of clearance rate is consistent with well-documented growth and clearance rate patterns.

Lung clearance index is a repeatable and sensitive indicator of radiological changes in bronchiectasis.

PubMed

Rowan, Stephen A; Bradley, Judy M; Bradbury, Ian; Lawson, John; Lynch, Tom; Gustafsson, Per; Horsley, Alex; O'Neill, Katherine; Ennis, Madeleine; Elborn, J Stuart

2014-03-01

In bronchiectasis there is a need for improved markers of lung function to determine disease severity and response to therapy. To assess whether the lung clearance index is a repeatable and more sensitive indicator of computed tomography (CT) scan abnormalities than spirometry in bronchiectasis. Thirty patients with stable bronchiectasis were recruited and lung clearance index, spirometry, and health-related quality of life measures were assessed on two occasions, 2 weeks apart when stable (study 1). A separate group of 60 patients with stable bronchiectasis was studied on a single visit with the same measurements and a CT scan (study 2). In study 1, the intervisit intraclass correlation coefficient for the lung clearance index was 0.94 (95% confidence interval, 0.89 to 0.97; P < 0.001). In study 2, the mean age was 62 (10) years, FEV1 76.5% predicted (18.9), lung clearance index 9.1 (2.0), and total CT score 14.1 (10.2)%. The lung clearance index was abnormal in 53 of 60 patients (88%) and FEV1 was abnormal in 37 of 60 patients (62%). FEV1 negatively correlated with the lung clearance index (r = -0.51, P < 0.0001). Across CT scores, there was a relationship with the lung clearance index, with little evidence of an effect of FEV1. There were no significant associations between the lung clearance index or FEV1 and health-related quality of life. The lung clearance index is repeatable and a more sensitive measure than FEV1 in the detection of abnormalities demonstrated on CT scan. The lung clearance index has the potential to be a useful clinical and research tool in patients with bronchiectasis.

Inert gas clearance from tissue by co-currently and counter-currently arranged microvessels

PubMed Central

Lu, Y.; Michel, C. C.

2012-01-01

To elucidate the clearance of dissolved inert gas from tissues, we have developed numerical models of gas transport in a cylindrical block of tissue supplied by one or two capillaries. With two capillaries, attention is given to the effects of co-current and counter-current flow on tissue gas clearance. Clearance by counter-current flow is compared with clearance by a single capillary or by two co-currently arranged capillaries. Effects of the blood velocity, solubility, and diffusivity of the gas in the tissue are investigated using parameters with physiological values. It is found that under the conditions investigated, almost identical clearances are achieved by a single capillary as by a co-current pair when the total flow per tissue volume in each unit is the same (i.e., flow velocity in the single capillary is twice that in each co-current vessel). For both co-current and counter-current arrangements, approximate linear relations exist between the tissue gas clearance rate and tissue blood perfusion rate. However, the counter-current arrangement of capillaries results in less-efficient clearance of the inert gas from tissues. Furthermore, this difference in efficiency increases at higher blood flow rates. At a given blood flow, the simple conduction-capacitance model, which has been used to estimate tissue blood perfusion rate from inert gas clearance, underestimates gas clearance rates predicted by the numerical models for single vessel or for two vessels with co-current flow. This difference is accounted for in discussion, which also considers the choice of parameters and possible effects of microvascular architecture on the interpretation of tissue inert gas clearance. PMID:22604885

Factors effective on peritoneal phosphorus transport and clearance in peritoneal dialysis patients
.

PubMed

Cebeci, Egemen; Gursu, Meltem; Uzun, Sami; Karadag, Serhat; Kazancioglu, Rumeyza; Ozturk, Savas

2017-02-01

Transport characteristics of phosphorus are different from other small solutes that are evaluated in routine peritoneal equilibration test (PET) in peritoneal dialysis (PD) patients. We aimed to evaluate peritoneal phosphorus clearance and permeability, and their relationship with peritoneal membrane transport type and creatinine clearance as well as factors affecting peritoneal phosphorus clearance. 70 adult patients on a PD program were included in our study. Phosphorus transport status was classified according to dialysate/plasma (D/P) phosphorus at the 4^th hour of PET as slow transporter (< 0.47), slow-average transporter (0.47 - 0.56), fast-average transporter (0.57 - 0.67), and fast transporter (> 0.67). We evaluated the relationship of peritoneal phosphorus clearance and transport type with PD regime, phosphorus level, and presence of residual renal function in addition to investigating factors that are effective on peritoneal phosphorus clearance. D/P phosphorus and peritoneal phosphorus clearance were positively correlated with D/P creatinine and peritoneal creatinine clearance, respectively. Automated PD and continuous ambulatory PD patients were similar regarding phosphorus and creatinine clearances and transport status based on D/P phosphorus. The major determinant of peritoneal phosphorus clearance was anuria status. Anuric patients had higher dialysate volume (11.6 ± 3.0 L vs. 8.4 ± 2.1 L, p < 0.001) and therefore higher peritoneal phosphorus clearance (61.7 ± 15.1 L/week/1.73 m² vs. 48.4 ± 14.0 L/week/1.73 m², p = 0.001). Hyperphosphatemia was present in 40% and 11% of anuric patients and those with residual renal function, respectively (p = 0.005). Peritoneal phosphorus transport characteristics are similar to that of creatinine. Although increased dialysis dose may increase peritoneal phosphorus clearance, it may be insufficient to prevent hyperphosphatemia in anuric patients.
.

Shape memory alloy adaptive control of gas turbine engine compressor blade tip clearance

NASA Astrophysics Data System (ADS)

Schetky, Lawrence M.; Steinetz, Bruce M.

1998-06-01

The ambient air ingested through the inlet of a gas turbine is first compressed by an axial compressor followed by further compression in a centrifugal compressor and then fed into the combustion chamber where ignition and expansion take place to produce the engine thrust. The axial compressor typically has five or more stages which consist of revolving blades and stators and the overall performance of the turbine is strongly affected by the compressor efficiency. When the turbine is turned on, to accommodate the rapid initial increase in the compressor blade length due to centrifugal force, the cold turbine has a built in clearance between the turbine blade tip and the casing. As the turbine reached its operating temperature there is a further increase in the blade length due to thermal expansion and, at the same time, the diameter of the casing increases. The net result is that when these various components have reached their equilibrium temperatures, the initial cold build clearance is reduced, but there remains a residual clearance. The magnitude of this clearance has a direct effect on the compressor efficiency and can be stated as: Δη/Δ CLR equals 0.5 where η is efficiency and CLR is the tip clearance. The concept of adaptive tip clearance control is based on the ability of a shape memory alloy ring to shrink to a predetermined diameter when heated to the temperature of a particular stage, and thus reducing the tip clearance. The ring is fabricated from a CuAlNi shape memory alloy and is mounted in the casing so as to be coaxial with the rotating blades of the particular stage. When cold, the ring dimensions are such as to provide the required cold build clearance, but when at operating temperature the reduced diameter creates a very small tip clearance. The clearance provided by this concept is much smaller than the clearance normally obtained for a turbine of the size being studied.

Simple sampling strategy for measuring inulin renal clearance.

PubMed

Horio, Masaru; Imai, Enyu; Yasuda, Yoshinari; Hishida, Akira; Matsuo, Seiichi

2009-02-01

In the standard method of inulin clearance (Cin), three sets of serum and urine samples are collected during a 2-hour clearance period. For a practical use of this method, sampling should be the minimal number allowable while still providing enough accuracy. The aim of this study was to evaluate the validity of inulin renal clearance with assumed single urine collection with a period such as 30, 60 or 90 minutes. Inulin clearance data collected by the standard method from 737 individuals were used. Changes of serum inulin concentrations between 45 and 105 minutes after the start of the infusion were analyzed. We used first urine collection to calculate the inulin clearance with single urine collection (Cin-30 min). We assumed single urine collection for 60 or 90 minutes by combining the urine data of the consecutive 30-minute periods. Inulin clearances (Cin-60 min, Cin-90 min) were calculated from the assumed single urine collections, respectively. Serum inulin concentration did not reach equilibrium during the clearance period. It increased in subjects with low glomerular filtration rate (GFR) and decreased in subjects with normal GFR. The amount of the change was small and -0.5 +/- 12.6% in subjects with GFR over 30 ml/min per 1.73 m(2). Cin-30 min, Cin-60 min and Cin-90 min showed high correlation coefficients against Cin-ST (0.962, 0.988 and 0.998, respectively). Systemic biases in these clearances were negligible (under 1 ml/min per 1.73 m(2)). Root mean square error (RMSE) were 10.4, 5.3 and 2.3 ml/min per 1.73 m(2) for Cin-30 min, Cin-60 min and Cin-90 min, respectively. These data indicated that accuracy of inulin clearance depends on the duration of the urine collection period. Inulin clearance with a single urine collection is a convenient method. We showed that single urine collection for 30 minutes or a longer period has reasonable accuracy in calculation of inulin clearance. We propose a method of inulin clearance with single urine collection for 60 minutes.

Augmented renal clearance in the ICU: results of a multicenter observational study of renal function in critically ill patients with normal plasma creatinine concentrations*.

PubMed

Udy, Andrew A; Baptista, João P; Lim, Noelle L; Joynt, Gavin M; Jarrett, Paul; Wockner, Leesa; Boots, Robert J; Lipman, Jeffrey

2014-03-01

To describe the prevalence and natural history of augmented renal clearance in a cohort of recently admitted critically ill patients with normal plasma creatinine concentrations. Multicenter, prospective, observational study. Four, tertiary-level, university-affiliated, ICUs in Australia, Singapore, Hong Kong, and Portugal. Study participants had to have an expected ICU length of stay more than 24 hours, no evidence of absolute renal impairment (admission plasma creatinine < 120 µmol/L), and no history of prior renal replacement therapy or chronic kidney disease. Convenience sampling was used at each participating site. Eight-hour urinary creatinine clearances were collected daily, as the primary method of measuring renal function. Augmented renal clearance was defined by a creatinine clearance more than or equal to 130 mL/min/1.73 m. Additional demographic, physiological, therapeutic, and outcome data were recorded prospectively. Nine hundred thirty-two patients were admitted to the participating ICUs over the study period, and 281 of which were recruited into the study, contributing 1,660 individual creatinine clearance measures. The mean age (95% CI) was 54.4 years (52.5-56.4 yr), Acute Physiology and Chronic Health Evaluation II score was 16 (15.2-16.7), and ICU mortality was 8.5%. Overall, 65.1% manifested augmented renal clearance on at least one occasion during the first seven study days; the majority (74%) of whom did so on more than or equal to 50% of their creatinine clearance measures. Using a mixed-effects model, the presence of augmented renal clearance on study day 1 strongly predicted (p = 0.019) sustained elevation of creatinine clearance in these patients over the first week in ICU. Augmented renal clearance appears to be a common finding in this patient group, with sustained elevation of creatinine clearance throughout the first week in ICU. Future studies should focus on the implications for accurate dosing of renally eliminated pharmaceuticals in patients with augmented renal clearance, in addition to the potential impact on individual clinical outcomes.

Effects of Double-Leakage Tip Clearance Flow on the Performance of a Compressor Stage with a Large Rotor Tip Gap

NASA Technical Reports Server (NTRS)

Hah, Chunill

2016-01-01

Effects of a large rotor tip gap on the performance of a one and half stage axial compressor are investigated in detail with a numerical simulation based on LES and available PIV data. The current paper studies the main flow physics, including why and how the loss generation is increased with the large rotor tip gap. The present study reveals that when the tip gap becomes large, tip clearance fluid goes over the tip clearance core vortex and enters into the next blade's tip gap, which is called double-leakage tip clearance flow. As the tip clearance flow enters into the adjacent blade's tip gap, a vortex rope with a lower pressure core is generated. This vortex rope breaks up the tip clearance core vortex of the adjacent blade, resulting in a large additional mixing. This double-leakage tip clearance flow occurs at all operating conditions, from design flow to near stall condition, with the large tip gap for the current compressor stage. The double-leakage tip clearance flow, its interaction with the tip clearance core vortex of the adjacent blade, and the resulting large mixing loss are the main flow mechanism of the large rotor tip gap in the compressor. When the tip clearance is smaller, flow near the end wall follows more closely with the main passage flow and this double-leakage tip clearance flow does not happen near the design flow condition for the current compressor stage. When the compressor with a large tip gap operates at near stall operation, a strong vortex rope is generated near the leading edge due to the double-leakage flow. Part of this vortex separates from the path of the tip clearance core vortex and travels from the suction side of the blade toward the pressure side of the blade. This vortex is generated periodically at near stall operation with a large tip gap. As the vortex travels from the suction side to the pressure side of the blade, a large fluctuation of local pressure forces blade vibration. Nonsynchronous blade vibration occurs due to this vortex as the frequency of this vortex generation is not the same as the rotor. The present investigation confirms that this vortex is a part of separated tip clearance vortex, which is caused by the double-leakage tip clearance flow.

30 CFR 18.24 - Electrical clearances.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Requirements § 18.24 Electrical clearances. Minimum clearances between uninsulated electrical conductor surfaces, or between uninsulated conductor surfaces and grounded metal surfaces, within the enclosure shall...

30 CFR 18.24 - Electrical clearances.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Requirements § 18.24 Electrical clearances. Minimum clearances between uninsulated electrical conductor surfaces, or between uninsulated conductor surfaces and grounded metal surfaces, within the enclosure shall...

7 CFR 1927.53 - Costs of title clearance and closing of transactions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 12 2010-01-01 2010-01-01 false Costs of title clearance and closing of transactions... and Loan Closing § 1927.53 Costs of title clearance and closing of transactions. The borrower or the... payment of all costs of title clearance and closing of the transaction and will arrange for payment before...

Not All Children with Cystic Fibrosis Have Abnormal Esophageal Neutralization during Chemical Clearance of Acid Reflux.

PubMed

Woodley, Frederick W; Moore-Clingenpeel, Melissa; Machado, Rodrigo Strehl; Nemastil, Christopher J; Jadcherla, Sudarshan R; Hayes, Don; Kopp, Benjamin T; Kaul, Ajay; Di Lorenzo, Carlo; Mousa, Hayat

2017-09-01

Acid neutralization during chemical clearance is significantly prolonged in children with cystic fibrosis, compared to symptomatic children without cystic fibrosis. The absence of available reference values impeded identification of abnormal findings within individual patients with and without cystic fibrosis. The present study aimed to test the hypothesis that significantly more children with cystic fibrosis have acid neutralization durations during chemical clearance that fall outside the physiological range. Published reference value for acid neutralization duration during chemical clearance (determined using combined impedance/pH monitoring) was used to assess esophageal acid neutralization efficiency during chemical clearance in 16 children with cystic fibrosis (3 to <18 years) and 16 age-matched children without cystic fibrosis. Duration of acid neutralization during chemical clearance exceeded the upper end of the physiological range in 9 of 16 (56.3%) children with and in 3 of 16 (18.8%) children without cystic fibrosis ( p =0.0412). The likelihood ratio for duration indicated that children with cystic fibrosis are 2.1-times more likely to have abnormal acid neutralization during chemical clearance, and children with abnormal acid neutralization during chemical clearance are 1.5-times more likely to have cystic fibrosis. Significantly more (but not all) children with cystic fibrosis have abnormally prolonged esophageal clearance of acid. Children with cystic fibrosis are more likely to have abnormal acid neutralization during chemical clearance. Additional studies involving larger sample sizes are needed to address the importance of genotype, esophageal motility, composition and volume of saliva, and gastric acidity on acid neutralization efficiency in cystic fibrosis children.

Esophageal Acid Clearance During Random Swallowing Is Faster in Patients with Barrett’s Esophagus Than in Healthy Controls

PubMed Central

Lottrup, Christian; Krarup, Anne L; Gregersen, Hans; Ejstrud, Per; Drewes, Asbjørn M

2016-01-01

Background/Aims Impaired esophageal acid clearance may be a contributing factor in the pathogenesis of Barrett’s esophagus. However, few studies have measured acid clearance as such in these patients. In this explorative, cross-sectional study, we aimed to compare esophageal acid clearance and swallowing rate in patients with Barrett’s esophagus to that in healthy controls. Methods A total of 26 patients with histology-confirmed Barrett’s esophagus and 12 healthy controls underwent (1) upper endoscopy, (2) an acid clearance test using a pH-impedance probe under controlled conditions including controlled and random swallowing, and (3) an ambulatory pH-impedance measurement. Results Compared with controls and when swallowing randomly, patients cleared acid 46% faster (P = 0.008). Furthermore, patients swallowed 60% more frequently (mean swallows/minute: 1.90 ± 0.74 vs 1.19 ± 0.58; P = 0.005), and acid clearance time decreased with greater random swallowing rate (P < 0.001). Swallowing rate increased with lower distal esophageal baseline impedance (P = 0.014). Ambulatory acid exposure was greater in patients (P = 0.033), but clearance times assessed from the ambulatory pH-measurement and acid clearance test were not correlated (all P > 0.3). Conclusions More frequent swallowing and thus faster acid clearance in Barrett’s esophagus may constitute a protective reflex due to impaired mucosal integrity and possibly acid hypersensitivity. Despite these reinforced mechanisms, acid clearance ability seems to be overthrown by repeated, retrograde acid reflux, thus resulting in increased esophageal acid exposure and consequently mucosal changes. PMID:27557545

Interstitial fluid drainage is impaired in ischemic stroke and Alzheimer’s disease mouse models

PubMed Central

Arbel-Ornath, Michal; Hudry, Eloise; Eikermann-Haerter, Katharina; Hou, Steven; Gregory, Julia L.; Zhao, Lingzhi; Betensky, Rebecca A.; Frosch, Matthew P.; Greenberg, Steven M.; Bacskai, Brian J.

2013-01-01

The interstitial fluid (ISF) drainage pathway has been hypothesized to underlie the clearance of solutes and metabolites from the brain. Previous work has implicated the perivascular spaces along arteries as the likely route for ISF clearance, however it has never been demonstrated directly. The accumulation of amyloid β (Aβ) peptides in brain parenchyma is one of the pathological hallmarks of Alzheimer disease (AD), and it is likely related to an imbalance between production and clearance of the peptide. Aβ drainage along perivascular spaces has been postulated to be one of the mechanisms that mediates the peptide clearance from the brain. We therefore devised a novel method to visualize solute clearance in real time in the living mouse brain using laser guided bolus dye injections and multiphoton imaging. This methodology allows high spatial and temporal resolution and revealed the kinetics of ISF clearance. We found that the ISF drains along perivascular spaces of arteries and capillaries but not veins, and its clearance exhibits a bi-exponential profile. ISF drainage requires a functional vasculature, as solute clearance decreased when perfusion was impaired. In addition, reduced solute clearance was observed in transgenic mice with significant vascular amyloid deposition; we suggest the existence of a feed-forward mechanism, by which amyloid deposition promotes further amyloid deposition. This important finding provides a mechanistic link between cerebrovascular disease and Alzheimer disease and suggests that facilitation of Aβ clearance along the perivascular pathway should be considered as a new target for therapeutic approaches to AD and CAA. PMID:23818064

Allometric scaling for predicting human clearance of bisphenol A

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

Collet, Séverine H., E-mail: s.collet@envt.fr; Picard-Hagen, Nicole, E-mail: n.hagen-picard@envt.fr; Lacroix, Marlène Z., E-mail: m.lacroix@envt.fr

The investigation of interspecies differences in bisphenol A (BPA) pharmacokinetics (PK) may be useful for translating findings from animal studies to humans, identifying major processes involved in BPA clearance mechanisms, and predicting BPA PK parameters in man. For the first time, a large range of species in terms of body weight, from 0.02 kg (mice) to 495 kg (horses) was used to predict BPA clearance in man by an allometric approach. BPA PK was evaluated after intravenous administration of BPA in horses, sheep, pigs, dogs, rats and mice. A non-compartmental analysis was used to estimate plasma clearance and steady statemore » volume of distribution and predict BPA PK parameters in humans from allometric scaling. In all the species investigated, BPA plasma clearance was high and of the same order of magnitude as their respective hepatic blood flow. By an allometric scaling, the human clearance was estimated to be 1.79 L/min (equivalent to 25.6 mL/kg.min) with a 95% prediction interval of 0.36 to 8.83 L/min. Our results support the hypothesis that there are highly efficient and hepatic mechanisms of BPA clearance in man. - Highlights: • Allometric scaling was used to predict BPA pharmacokinetic parameters in humans. • In all species, BPA plasma clearance approached hepatic blood flow. • Human BPA clearance was estimated to be 1.79 L/min.« less

Delayed clearance of triglyceride‐rich lipoproteins in young, healthy obese subjects†

PubMed Central

Goll, R.; Lekahl, S.; Moen, O. S.; Florholmen, J.

2015-01-01

Summary Obesity is associated with the metabolic syndrome. The aims were, first, to study the postprandial triglyceride clearance in young, healthy obese subjects and, second, to investigate if fasting triglycerides can predict delayed postprandial triglyceride clearance. Eighteen apparently healthy, obese subjects with no clinical signs of metabolic disturbances participated. Controls were age‐ and sex‐matched, healthy, normal weight subjects. Subclinical markers of metabolic disturbances were assessed by measuring postprandial triglycerides in serum and in chylomicrons by oral fat tolerance test. Postprandial triglyceride clearance for 8 h was assessed indirectly as removal of the lipid from serum during the oral fat tolerance test. Insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA‐IR). Twelve (66%) of the apparently healthy obese individuals had insulin resistance measured by HOMA‐IR. There was a delayed clearance of serum triglycerides and chylomicron triglycerides at 6 h when compared with the control group, while, at 8 h, the differences were only detected for the chylomicron triglyceride clearance. Triglyceride response was significantly greater in the obese subjects. Fasting triglycerides in upper normal level predicted a delayed postprandial triglyceride clearance and insulin resistance. In young, apparently healthy obese subjects early metabolic disturbances including insulin resistance and delayed postprandial triglyceride clearance can be detected. Fasting serum triglyceride in upper normal level predicted delayed postprandial triglyceride clearance and insulin resistance. PMID:26469529

Pharmacoepidemiologic investigation of clonazepam relative clearance by mixed-effect modeling using routine clinical pharmacokinetic data in Japanese patients.

PubMed

Yukawa, Eiji; Satou, Masayasu; Nonaka, Toshiharu; Yukawa, Miho; Ohdo, Shigehiro; Higuchi, Shun; Kuroda, Takeshi; Goto, Yoshinobu

2002-01-01

The effects of drug-drug interactions on clonazepam clearance were examined through a retrospective analysis of serum concentration data from pediatric and adult epileptic patients. Patients received clonazepam as monotherapy or in combination with other antiepileptic drugs. A total of 259 serum clonazepam concentrations gathered from 137 patients were used in a population analysis of drug-drug interactions on clonazepam clearance. Data were analyzed using a nonlinear mixed-effects modeling (NONMEM) technique. The final model describing clonazepam clearance was CL = 152 x TBW(-0.181) x DIF, where CL is clearance (ml/kg/h), TBWis total body weight (kg), and DIF (drug interaction factor) is a scaling factor for concomitant medication with a value of 1 for patients on clonazepam monotherapy, 1.18 for those patients receiving concomitant administration of clonazepam and one antiepileptic drug (carbamazepine or valproic acid), and 2.12 x TBW(-0.119) for those patients receiving concomitant administration of clonazepam and more than two antiepileptic drugs. Clonazepam clearance decreased in a weight-related fashion in children, with minimal changes observed in adults. Concomitant administration of clonazepam and carbamazepine resulted in a 22% increase in clonazepam clearance. Concomitant administration of clonazepam and valproic acid resulted in a 12% increase in clonazepam clearance. Concomitant administration of clonazepam with two or more antiepileptic drugs resulted in a 23% to 75% increase in clonazepam clearance.

Effect of clearance on cartilage tribology in hip hemi-arthroplasty.

PubMed

Lizhang, Jia; Taylor, Simon D; Jin, Zhongmin; Fisher, John; Williams, Sophie

2013-12-01

Hemi-arthroplasty of the hip (an artificial femoral head articulating against the natural acetabulum) is used to treat fractured necks of femur; however, there is evidence that articulation causes erosion of the cartilage, resulting in pain for the patient. Parameters that may influence this cartilage erosion include head material and roughness, clearance between the head and acetabulum and activity levels of the patient. This study has assessed the effect of clearance of hemi-arthroplasty articulations on the contact stress, friction and cartilage deformation in an in vitro tribological simulation of the hemi-arthroplasty joint that applied dynamic loads and motion. It has been demonstrated that peak contact stress increased from 5.6 to 10.6 MPa as radial clearance increased from small (<0.6 mm) to extra-large (>1.8 mm). In all samples, friction factor increased with time and was significantly less with extra-large clearances compared to small (<0.6 mm), medium (0.6-1.2 mm) and large (1.2-1.8 mm) clearances. The cartilage deformation observed was significantly greater in acetabulum samples paired to give small or extra-large clearances compared to those with medium or large clearances.

Dynamic modelling and experimental study of cantilever beam with clearance

NASA Astrophysics Data System (ADS)

Li, B.; Jin, W.; Han, L.; He, Z.

2012-05-01

Clearances occur in almost all mechanical systems, typically such as the clearance between slide plate of gun barrel and guide. Therefore, to study the clearances of mechanisms can be very important to increase the working performance and lifetime of mechanisms. In this paper, rigid dynamic modelling of cantilever with clearance was done according to the subject investigated. In the rigid dynamic modelling, clearance is equivalent to the spring-dashpot model, the impact of beam and boundary face was also taken into consideration. In ADAMS software, the dynamic simulation was carried out according to the model above. The software simulated the movement of cantilever with clearance under external excitation. Research found: When the clearance is larger, the force of impact will become larger. In order to study how the stiffness of the cantilever's supporting part influences natural frequency of the system, A Euler beam which is restricted by a draught spring and a torsion spring at its end was raised. Through numerical calculation, the relationship between natural frequency and stiffness was found. When the value of the stiffness is close to the limit value, the corresponding boundary condition is illustrated. An ADAMS experiment was carried out to check the theory and the simulation.

Acute Effects of Walking Exercise on Stair Negotiation in Sedentary and Physically Active Older Adults.

PubMed

Kunzler, Marcos R; da Rocha, Emmanuel S; Bobbert, Maarten F; Duysens, Jacques; Carpes, Felipe P

2017-07-01

In negotiating stairs, low foot clearance increases the risk of tripping and a fall. Foot clearance may be related to physical fitness, which differs between active and sedentary participants, and be acutely affected by exercise. Impaired stair negotiation could be an acute response to exercise. Here we determined acute changes in foot clearances during stair walking in sedentary (n = 15) and physically active older adults (n = 15) after prolonged exercise. Kinematic data were acquired during negotiation with a 3-steps staircase while participants walked at preferred speed, before and after 30 min walking at preferred speed and using a treadmill. Foot clearances were compared before and after exercise and between the groups. Sedentary older adults presented larger (0.5 cm for lead and 2 cm for trail leg) toe clearances in ascent, smaller (0.7 cm) heel clearance in the leading foot in descent, and larger (1 cm) heel clearance in the trailing foot in descent than physically active. Sedentary older adults negotiate stairs in a slightly different way than active older adults, and 30 min walking at preferred speed does not affect clearance in stair negotiation.

Rotor tip clearance effects on overall and blade-element performance of axial-flow transonic fan stage

NASA Technical Reports Server (NTRS)

Moore, R. D.

1982-01-01

The effects of tip clearance on the overall and blade-element performance of an axial-flow transonic fan stage are presented. The 50-centimeter-diameter fan was tested at four tip clearances (nonrotating) from 0.061 to 0.178 centimeter. The calculated radial growth of the blades was 0.040 centimeter at design conditions. The decrease in overall stage performance with increasing clearance is attributed to the loss in rotor performance. For the rotor the effects of clearance on performance parameters extended to about 70 percent of blade span from the tip. The stage still margin based on an assumed operating line decreased from 15.3 to 0 percent as the clearance increased from 0.061 to 0.178 centimeter.

Methods and apparatus for controlling rotary machines

DOEpatents

Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Scotia, NY; Barnes, Gary R [Delanson, NY; Fric, Thomas Frank [Greer, SC; Lyons, James Patrick Francis [Niskayuna, NY; Pierce, Kirk Gee [Simpsonville, SC; Holley, William Edwin [Greer, SC; Barbu, Corneliu [Guilderland, NY

2009-09-01

A control system for a rotary machine is provided. The rotary machine has at least one rotating member and at least one substantially stationary member positioned such that a clearance gap is defined between a portion of the rotating member and a portion of the substantially stationary member. The control system includes at least one clearance gap dimension measurement apparatus and at least one clearance gap adjustment assembly. The adjustment assembly is coupled in electronic data communication with the measurement apparatus. The control system is configured to process a clearance gap dimension signal and modulate the clearance gap dimension.

Modified Augmented Renal Clearance Score Predicts Rapid Piperacillin and Tazobactam Clearance in Critically Ill Surgery and Trauma Patients

DTIC Science & Technology

2014-04-24

intermittent dosing regimens. CONCLUSION: Given its ability to predict antimicrobial clearance above populationmedians, which could compromise therapy, the...campaign dedicated to improve out- comes.1,2 In the era ofmultiply drug- resistant pathogens and rising antimicrobial minimum inhibitory concentrations (MICs...urinary creatinine clearance significantly exceeds what is predicted by the serum creatinine concentration according to various mathematical

46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

Code of Federal Regulations, 2014 CFR

2014-10-01

... worn down to 6.4 mm (0.25 in) clearance for shafts of 229 mm (9 in) or less in diameter, 7.95 mm (0.3125 in) clearance for shafts exceeding 229 mm (9 in) but not exceeding 305 mm (12 in) in diameter, and 9.53 mm (0.375 in) clearance for shafts exceeding 305 mm (12 in) in diameter. (2) Where the...

46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

Code of Federal Regulations, 2012 CFR

2012-10-01

... worn down to 6.4 mm (0.25 in) clearance for shafts of 229 mm (9 in) or less in diameter, 7.95 mm (0.3125 in) clearance for shafts exceeding 229 mm (9 in) but not exceeding 305 mm (12 in) in diameter, and 9.53 mm (0.375 in) clearance for shafts exceeding 305 mm (12 in) in diameter. (2) Where the...

46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

Code of Federal Regulations, 2010 CFR

2010-10-01

... worn down to 6.4 mm (0.25 in) clearance for shafts of 229 mm (9 in) or less in diameter, 7.95 mm (0.3125 in) clearance for shafts exceeding 229 mm (9 in) but not exceeding 305 mm (12 in) in diameter, and 9.53 mm (0.375 in) clearance for shafts exceeding 305 mm (12 in) in diameter. (2) Where the...

46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

Code of Federal Regulations, 2011 CFR

2011-10-01

... worn down to 6.4 mm (0.25 in) clearance for shafts of 229 mm (9 in) or less in diameter, 7.95 mm (0.3125 in) clearance for shafts exceeding 229 mm (9 in) but not exceeding 305 mm (12 in) in diameter, and 9.53 mm (0.375 in) clearance for shafts exceeding 305 mm (12 in) in diameter. (2) Where the...

46 CFR 61.20-23 - Tailshaft clearance; bearing weardown.

Code of Federal Regulations, 2013 CFR

2013-10-01

... worn down to 6.4 mm (0.25 in) clearance for shafts of 229 mm (9 in) or less in diameter, 7.95 mm (0.3125 in) clearance for shafts exceeding 229 mm (9 in) but not exceeding 305 mm (12 in) in diameter, and 9.53 mm (0.375 in) clearance for shafts exceeding 305 mm (12 in) in diameter. (2) Where the...

Effect of amiloride and saline on nasal mucociliary clearance and potential difference in cystic fibrosis and normal subjects.

PubMed Central

Middleton, P. G.; Geddes, D. M.; Alton, E. W.

1993-01-01

BACKGROUND--Mucociliary clearance is an important component of pulmonary defence. Maximum clearance is thought to depend on an optimal depth of the sol layer, allowing the most efficient interaction between the cilia and the overlying mucus layer. Sodium absorption, the major ion transport in human airways, is thought to be important in the regulation of the depth of the sol layer. In the airways of patients with cystic fibrosis sodium absorption is increased and mucociliary clearance decreased. Amiloride, a sodium channel blocker, has been shown to improve pulmonary mucociliary clearance in patients with cystic fibrosis. However, its effects on nasal mucociliary clearance in either normal subjects or those with cystic fibrosis are unknown. A study was therefore performed to investigate whether nebulised amiloride improves nasal mucociliary clearance in normal or cystic fibrosis subjects. METHODS--Nasal mucociliary clearance was measured by the saccharin clearance technique in 12 normal subjects and 12 with cystic fibrosis. For the control study measurements were made on two consecutive days and the mean time for each subject averaged. For the drug study measurements were also made on two consecutive days, after administration of nasally nebulised amiloride or placebo (saline) in a double blind manner. Nasal potential difference was measured in eight patients with cystic fibrosis after the administration of amiloride or placebo to assess the efficacy of deposition and duration of action. RESULTS--Baseline values of mucociliary clearance were significantly faster in the normal subjects than in those with cystic fibrosis. In both groups mucociliary clearance was increased after both saline and amiloride, with no significant difference between either treatment. As previously reported, baseline nasal potential difference was significantly more negative in the subjects with cystic fibrosis. Amiloride significantly reduced the potential difference for at least 60 minutes in these subjects. CONCLUSIONS--Nebulised saline significantly improves nasal mucociliary clearance in both normal subjects and those with cystic fibrosis. Amiloride did not appear to exert any additional effects in either group of subjects, despite evidence of its efficacy of deposition. PMID:8211871

Pregnancy Increases the Renal Secretion of N1-methylnicotinamide, an Endogenous Probe for Renal Cation Transporters, in Patients Prescribed Metformin.

PubMed

Bergagnini-Kolev, Mackenzie C; Hebert, Mary F; Easterling, Thomas R; Lin, Yvonne S

2017-03-01

N 1 -methylnicotinamide (1-NMN) has been investigated as an endogenous probe for the renal transporter activity of organic cation transporter 2 (OCT2) and multidrug and toxin extrusion proteins 1 and 2-K (MATE1 and MATE2-K). As pregnancy increased the renal secretion of metformin, a substrate for OCT2, MATE1, and MATE2-K, we hypothesized that the renal secretion of 1-NMN would be similarly affected. Blood and urine samples collected from women prescribed metformin for type 2 diabetes, gestational diabetes, and polycystic ovarian syndrome during early, mid, and late pregnancy ( n = 34 visits) and postpartum ( n = 14 visits) were analyzed for 1-NMN using liquid chromatography-mass spectrometry. The renal clearance and secretion clearance, using creatinine clearance to correct for glomerular filtration, were estimated for 1-NMN and correlated with metformin renal clearance. 1-NMN renal clearance was higher in both mid (504 ± 293 ml/min, P < 0.01) and late pregnancy (557 ± 305 ml/min, P < 0.01) compared with postpartum (240 ± 106 ml/min). The renal secretion of 1-NMN was 3.5-fold higher in mid pregnancy (269± 267, P < 0.05) and 4.5-fold higher in late pregnancy compared with postpartum (342 ± 283 versus 76 ± 92 ml/min, P < 0.01). Because creatinine is also a substrate of OCT2, MATE1, and MATE2-K, creatinine clearance likely overestimates filtration clearance, whereas the calculated 1-NMN secretion clearance is likely underestimated. Metformin renal clearance and 1-NMN renal clearance were positively correlated (r s = 0.68, P < 0.0001). 1-NMN renal clearance increases during pregnancy due to increased glomerular filtration and net secretion by renal transporters. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Impact of impaired renal function on the pharmacokinetics of the antiepileptic drug lacosamide.

PubMed

Cawello, Willi; Fuhr, Uwe; Hering, Ursula; Maatouk, Haidar; Halabi, Atef

2013-10-01

The antiepileptic drug lacosamide is eliminated predominantly via the kidneys. Therefore, an evaluation of the impact of renal impairment on its pharmacokinetic profile is an important component of its safety assessment. The objective of this study was to evaluate the pharmacokinetic profile of lacosamide among individuals with renal impairment (mild, moderate, or severe) and among patients with end-stage renal disease (ESRD), including those on hemodialysis. This was an open-label, Phase I trial. The pharmacokinetics of a single oral 100-mg lacosamide dose were evaluated in five groups of participants: healthy controls, patients with mild, moderate, or severe renal impairment, and patients with ESRD (with and without hemodialysis). Forty participants completed the trial, eight in each group. In healthy volunteers, renal clearance accounted for approximately 30 % of total body clearance [geometric mean 0.5897 l/h (coefficient of variation 37.9 %) vs 2.13 l/h (20.8 %)]. With severe renal impairment, renal clearance was approximately 11 % of total body clearance [0.1428 l/h (31.8 %) vs 1.34 l/h (26.9 %)]. Terminal half-life and systemic exposure were increased with renal impairment, while total body clearance, renal clearance, and urinary excretion were decreased. Strong positive correlations between creatinine clearance, renal clearance, and urinary excretion were observed. Among patients with ESRD, approximately 50 % of lacosamide was cleared from systemic circulation by 4-h hemodialysis. In patients with essentially no renal clearance, nonrenal clearance was still present (1.1 l/h). Lacosamide was well tolerated by healthy volunteers and patients. In patients with mild-to-moderate renal impairment, lacosamide dose adjustment is not necessary, because total body clearance decreased by only approximately 20 %. Dose adjustment, however, is required for patients with severe renal impairment. Hemodialysis removes approximately 50 % of lacosamide from plasma; therefore, dose supplementation following hemodialysis should be considered.

Dimerization of glycoprotein Ibα is not sufficient to induce platelet clearance.

PubMed

Liang, X; Syed, A K; Russell, S R; Ware, J; Li, R

2016-02-01

ESSENTIALS: Many anti-glycoprotein (GP)Ibα antibodies induce platelet clearance in a dimer-dependent manner. Characterization of monoclonal antibodies that bind the mechanosensitive domain (MSD) of GPIbα. An anti-MSD antibody binds two copies of GPIbα in platelets but does not induce platelet clearance. The prevailing clustering model of GPIbα signaling is incorrect or needs revision. The mechanism of platelet clearance is not clear. Many antibodies binding the membrane-distal ligand-binding domain of glycoprotein (GP)Ibα induce rapid clearance of platelets and acute thrombocytopenia, which requires the bifurcated antibody structure. It was thought that binding of these antibodies induced lateral dimerization or clustering of GPIbα in the plasma membrane, which leads to downstream signaling and platelet clearance. However, many antibodies targeting GPIbβ and GPIX, which are associated with GPIbα in the GPIb-IX complex, do not induce platelet clearance, which is in contradiction to the clustering model. To test whether dimerization or clustering of GPIbα is sufficient to transmit the signal that leads to platelet clearance. We have recently raised several mAbs targeting the mechanosensitive domain (MSD) of GPIbα. Binding of these anti-MSD antibodies was characterized with biochemical methods. Their ability to stimulate platelets and induce platelet clearance in mice was assessed. Infusion of anti-MSD antibodies does not cause thrombocytopenia in mice. These antibodies show no detectable effects on platelet activation and aggregation in vitro. Further biochemical investigation showed that the anti-MSD antibody 3D1 binds two copies of GPIbα on the platelet surface. Therefore, lateral dimerization of GPIbα induced by antibody binding is not sufficient to initiate GPIb-IX signaling and induce platelet clearance. Our results suggest that a factor other than or in addition to clustering of GPIbα is required to induce platelet clearance. © 2015 International Society on Thrombosis and Haemostasis.

76 FR 34761 - Classified National Security Information

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-14

... Commission is a micro agency of 14 full time permanent employees. Three employees have current Secret clearances and one staff has a Top Secret clearance. These employees require clearances because they attend...

Reliability of ⁵¹Cr-EDTA plasma and urinary clearance as a measure of residual renal function in dialysis patients.

PubMed

Kjaergaard, Krista D; Jensen, Jens D; Jespersen, Bente; Rehling, Michael

2011-12-01

In dialysis patients, longer survival is associated with a higher residual renal function. Randomized controlled trials are conducted to clarify how residual renal function can be preserved. However, existing methods for measuring residual renal function are uncertain and there is a need for establishing a standard for measurements of glomerular filtration rate (GFR) in dialysis patients. ⁵¹Cr-EDTA clearances in plasma, urine, and dialysate were evaluated in a sample of 12 hemodialysis and 12 peritoneal dialysis patients. The patients' condition was generally stable, and all patients were investigated twice within 4-10 days. Plasma clearances of ⁵¹Cr-EDTA for all patients ranged between 2.1 and 30.8 mL/min/1.73 m², whereas urinary ⁵¹Cr-EDTA clearances ranged from 0.7-20.0 mL/min/1.73 m². This difference was statistically significant (p < 0.001). Week-to-week reproducibility expressed as coefficients of variation were below or equal to 10% for plasma clearances and 13% for urinary clearances in hemodialysis patients and 14% in peritoneal dialysis patients. This study demonstrated a difference between ⁵¹Cr-EDTA plasma and urinary clearances in dialysis patients. Plasma clearance of ⁵¹Cr-EDTA had the best reproducibility. For repeated measurements as in clinical prospective trials, we recommend ⁵¹Cr-EDTA plasma clearance based on blood sampling at 5 + 24 hours with subtraction of ⁵¹Cr-EDTA dialysate clearance in peritoneal dialysis patients. Further studies are needed to corroborate our findings.

Selectively increasing the clearance of protein-bound uremic solutes

PubMed Central

Luo, Frank J.-G.; Plummer, Natalie S.; Hostetter, Thomas H.; Meyer, Timothy W.

2012-01-01

Background. The toxicity of bound solutes could be better evaluated if we could adjust the clearance of such solutes independent of unbound solutes. This study assessed whether bound solute clearances can be increased while maintaining urea clearance constant during the extended hours of nocturnal dialysis. Methods. Nine patients on thrice-weekly nocturnal dialysis underwent two experimental dialysis treatments 1 week apart. The experimental treatments were designed to provide the same urea clearance while providing widely different bound solute clearance. One treatment employed a large dialyzer and high dialyzate flow rate (Qd) of 800 mL/min while blood flow (Qb) was 270 mL/min. The other treatment employed a smaller dialyzer and Qd of 300 mL/min while Qb was 350 mL/min. Results. Treatment with the large dialyzer and higher Qd greatly increased the clearances of the bound solutes p-cresol sulfate (PCS: 27 ± 9 versus 14 ± 6 mL/min) and indoxyl sulfate (IS: 26 ± 8 versus 14 ± 5 mL/min) without altering the clearance of urea (204 ± 20 versus 193 ± 16 mL/min). Increasing PCS and IS clearances increased the removal of these solutes (PCS: 375 ± 200 versus 207 ± 86 mg/session; IS: 201 ± 137 versus 153 ± 74 mg/session), while urea removal was not different. Conclusions. The removal of bound solutes can thus be increased by raising the dialyzate flow and dialyzer size above the low levels sufficient to achieve target Kt/Vurea during extended treatment. Selectively increasing the clearance of bound solutes provides a potential means to test their toxicity. PMID:22231033

Four hour creatinine clearance is better than plasma creatinine for monitoring renal function in critically ill patients

PubMed Central

2012-01-01

Introduction Acute kidney injury (AKI) diagnosis is based on an increase in plasma creatinine, which is a slowly changing surrogate of decreased glomerular filtration rate. We investigated whether serial creatinine clearance, a direct measure of the glomerular filtration rate, provided more timely and accurate information on renal function than serial plasma creatinine in critically ill patients. Methods Serial plasma creatinine and 4-hour creatinine clearance were measured 12-hourly for 24 hours and then daily in 484 patients. AKI was defined either as > 50% increase in plasma creatinine from baseline, or > 33.3% decrease in creatinine clearance. The diagnostic and predictive performance of the two AKI definitions were compared. Results Creatinine clearance decrease diagnosed AKI in 24% of those not diagnosed by plasma creatinine increase on entry. These patients entered the ICU sooner after insult than those diagnosed with AKI by plasma creatinine elevation (P = 0.0041). Mortality and dialysis requirement increased with the change in creatinine clearance-acute kidney injury severity class (P = 0.0021). Amongst patients with plasma creatinine < 1.24 mg/dl on entry, creatinine clearance improved the prediction of AKI considerably (Net Reclassification Improvement 83%, Integrated Discrimination Improvement 0.29). On-entry, creatinine clearance associated with AKI severity and duration (P < 0.0001) predicted dialysis need (area under the curve: 0.75) and death (0.61). A > 33.3% decrease in creatinine clearance over the first 12 hours was associated with a 2.0-fold increased relative risk of dialysis or death. Conclusions Repeated 4-hour creatinine clearance measurements in critically ill patients allow earlier detection of AKI, as well as progression and recovery compared to plasma creatinine. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN012606000032550. PMID:22713519

Increased dependence of leucine in posttraumatic sepsis: leucine/tyrosine clearance ratio as an indicator of hepatic impairment in septic multiple organ failure syndrome.

PubMed

Pittiruti, M; Siegel, J H; Sganga, G; Coleman, B; Wiles, C E; Belzberg, H; Wedel, S; Placko, R

1985-09-01

The body clearance of 10 plasma amino acids (AA) was determined from the rate of compared muscle-released AA and AA administered by infusion of total parenteral nutrition (TPN) compared to their estimated extracellular (ECW) pool in patients with multiple trauma with (n = 10) or without (n = 16) sepsis at 8-hour intervals. In both nonseptic and septic trauma, increasing TPN increased the mean clearance rate of all infused AA. When the individual AA clearance rates were normalized by the total AA infusion rate, regression-covariance analysis revealed that patients with sepsis had relatively impaired clearances of alanine (p less than 0.01) and methionine, proline, phenylalanine, and tyrosine p less than 0.05 for all). In contrast, the clearances of branched-chain AA (BCAA) valine and isoleucine were maintained, and the clearance of leucine was higher (p less than 0.05) in trauma patients with sepsis than in those without. At any AA infusion rate, compared with surviving patients with sepsis (p less than 0.05), patients who developed fatal multiple organ failure syndrome (MOFS) showed increased clearances of all BCAA with further impaired clearance of tyrosine. The clearance ratio of leucine/tyrosine was increased in MOFS at any AA infusion rate (p less than 0.0001), was an indicator of severity, and, if persistent, was a manifestation of a fatal outcome. Because tyrosine metabolism occurs almost entirely in the liver while leucine can be utilized by viscera and muscle, these data suggest early and progressive septic impairment of the pattern of hepatic uptake and oxidation of AA with a greater body dependence on BCAA, especially leucine, as septic MOFS develops.

Single-sample 99mTc-diethylenetriamine penta-acetate plasma clearance in advanced renal failure by the mean sojourn time approach.

PubMed

Gref, Margareta C; Karp, Kjell H

2009-03-01

The single-sample Tc-diethylenetriamine penta-acetate (DTPA) clearance method by Christensen and Groth is recommended by the Radionuclides in Nephrourology Committee on Renal Clearance for use in adults with an estimated glomerular filtration rate (GFR) > or = 30 ml/min. The purpose of this study was to test a new Tc-DTPA single-sample low clearance formula for GFR lesser than 30 ml/min. Twenty-one adult patients (29 investigations) were included. Reference clearance was calculated with both Cr-EDTA and Tc-DTPA according to Brøchner-Mortensen with samples drawn between 3 and 24 h. Single-sample clearance was calculated from a 24 h sample using the low clearance formula(Equation is included in full-text article.) C(t) is the activity of the tracer in the plasma sample t minutes after the injection and Q0 is the injected amount. ECV is the extracellular volume in ml defined as the distribution volume of the tracer. ECV is estimated from the body surface area as ECV=8116.6xbody surface area-28.2. The mean difference between reference and Tc-DTPA single-sample clearance was -0.5 ml/min (SD 1.0 ml/min) for Tc-DTPA and -0.8 ml/min (SD 1.2 ml/min) for Cr-EDTA as reference clearance. In adult patients it is possible, even with GFR lesser than 30 ml/min, to get an accurate determination of Tc-DTPA plasma clearance from a single sample using the mean sojourn time approach. The blood sample should be obtained about 24 h after injection of the GFR tracer.

Wear in ceramic on ceramic type lumbar total disc replacement: effect of radial clearance.

PubMed

Shankar, S; Kesavan, D

2015-01-01

The wear of the bearing surfaces of total disc replacement (TDR) is a key problem leads to reduction in the lifetime of the prosthesis and it mainly occurs due to the range of clearances of the articulating surface between the superior plate and core. The objective of this paper is to estimate the wear using finite element concepts considering the different radial clearances between the articulating surfaces of ceramic on ceramic type Lumbar Total Disc Replacement (LTDR). The finite element (FE) model was subjected to wear testing protocols according to loading profile of International Standards Organization (ISO) 18192 standards through 10 million cycles. The radial clearance value of 0.05 mm showed less volumetric wear when compared with other radial clearance values. Hence, low radial clearance values are suitable for LTDR to minimize the wear.

Sealing in Turbomachinery

NASA Technical Reports Server (NTRS)

Chupp, Raymond E.; Hendricks, Robert C.; Lattime, Scott B.; Steinetz, Bruce M.

2006-01-01

Clearance control is of paramount importance to turbomachinery designers and is required to meet today's aggressive power output, efficiency, and operational life goals. Excessive clearances lead to losses in cycle efficiency, flow instabilities, and hot gas ingestion into disk cavities. Insufficient clearances limit coolant flows and cause interface rubbing, overheating downstream components and damaging interfaces, thus limiting component life. Designers have put renewed attention on clearance control, as it is often the most cost effective method to enhance system performance. Advanced concepts and proper material selection continue to play important roles in maintaining interface clearances to enable the system to meet design goals. This work presents an overview of turbomachinery sealing to control clearances. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues.

Novel sensors to enable closed-loop active clearance control in gas turbine engines

NASA Astrophysics Data System (ADS)

Geisheimer, Jonathan; Holst, Tom

2014-06-01

Active clearance control within the turbine section of gas turbine engines presents and opportunity within aerospace and industrial applications to improve operating efficiencies and the life of downstream components. Open loop clearance control is currently employed during the development of all new large core aerospace engines; however, the ability to measure the gap between the blades and the case and close down the clearance further presents as opportunity to gain even greater efficiencies. The turbine area is one of the harshest environments for long term placement of a sensor in addition to the extreme accuracy requirements required to enable closed loop clearance control. This paper gives an overview of the challenges of clearance measurements within the turbine as well as discusses the latest developments of a microwave sensor designed for this application.

A Parametric Study of Actuator Requirements for Active Turbine Tip Clearance Control of a Modern High Bypass Turbofan Engine

NASA Technical Reports Server (NTRS)

Kratz, Jonathan L.; Chapman, Jeffryes W.; Guo, Ten-Huei

2017-01-01

The efficiency of aircraft gas turbine engines is sensitive to the distance between the tips of its turbine blades and its shroud, which serves as its containment structure. Maintaining tighter clearance between these components has been shown to increase turbine efficiency, increase fuel efficiency, and reduce the turbine inlet temperature, and this correlates to a longer time-on-wing for the engine. Therefore, there is a desire to maintain a tight clearance in the turbine, which requires fast response active clearance control. Fast response active tip clearance control will require an actuator to modify the physical or effective tip clearance in the turbine. This paper evaluates the requirements of a generic active turbine tip clearance actuator for a modern commercial aircraft engine using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k) software that has previously been integrated with a dynamic tip clearance model. A parametric study was performed in an attempt to evaluate requirements for control actuators in terms of bandwidth, rate limits, saturation limits, and deadband. Constraints on the weight of the actuation system and some considerations as to the force which the actuator must be capable of exerting and maintaining are also investigated. From the results, the relevant range of the evaluated actuator parameters can be extracted. Some additional discussion is provided on the challenges posed by the tip clearance control problem and the implications for future small core aircraft engines.

Estimation of end point foot clearance points from inertial sensor data.

PubMed

Santhiranayagam, Braveena K; Lai, Daniel T H; Begg, Rezaul K; Palaniswami, Marimuthu

2011-01-01

Foot clearance parameters provide useful insight into tripping risks during walking. This paper proposes a technique for the estimate of key foot clearance parameters using inertial sensor (accelerometers and gyroscopes) data. Fifteen features were extracted from raw inertial sensor measurements, and a regression model was used to estimate two key foot clearance parameters: First maximum vertical clearance (m x 1) after toe-off and the Minimum Toe Clearance (MTC) of the swing foot. Comparisons are made against measurements obtained using an optoelectronic motion capture system (Optotrak), at 4 different walking speeds. General Regression Neural Networks (GRNN) were used to estimate the desired parameters from the sensor features. Eight subjects foot clearance data were examined and a Leave-one-subject-out (LOSO) method was used to select the best model. The best average Root Mean Square Errors (RMSE) across all subjects obtained using all sensor features at the maximum speed for m x 1 was 5.32 mm and for MTC was 4.04 mm. Further application of a hill-climbing feature selection technique resulted in 0.54-21.93% improvement in RMSE and required fewer input features. The results demonstrated that using raw inertial sensor data with regression models and feature selection could accurately estimate key foot clearance parameters.

Cleaning up the mess: cell corpse clearance in Caenorhabditis elegans.

PubMed

Pinto, Sérgio Morgado; Hengartner, Michael Otmar

2012-12-01

Genetic and cell biology studies have led to the identification in Caenorhabditis elegans of a set of evolutionary conserved cellular mechanisms responsible for the clearance of apoptotic cells. Based on the phenotype of cell corpse clearance mutants, corpse clearance can be divided into three distinct, but linked steps: corpse recognition, corpse internalization, and corpse degradation. Work in recent years has led to a better understanding of the molecular pathways that mediate each of these steps. Here, we review recent developments in our understanding of in vivo cell corpse clearance in this simple but most elegant model organism. Copyright © 2012 Elsevier Ltd. All rights reserved.

CF6 Jet Engine Diagnostics Program: High pressure compressor clearance investigation

NASA Technical Reports Server (NTRS)

Radomski, M. A.

1982-01-01

The effects of high pressure compressor clearance changes on engine performance were experimentally determined on a CF6 core engine. The results indicate that a one percent reduction in normalized average clearance, expressed as a fraction of airfoil length, improves compressor efficiency by one percent. Compressor clearances are reduced by the application of rotor bore cooling, insulation of the stator casing, and use of a low coefficient of expansion material in the aft stages. This improvement amounts to a reduction of normalized average clearance of 0.78 percent, relative to CF6-60 compressor, which is equivalent to an improvement in compressor efficiency of 0.78 percent.

Collision-free coordination of fiber positioners in multi-object spectrographs

NASA Astrophysics Data System (ADS)

Makarem, Laleh; Kneib, Jean-Paul; Gillet, Denis

2016-07-01

Many fiber-fed spectroscopic survey projects, such as DESI, PFS and MOONS, will use thousands of fiber positioners packed at a focal plane. To maximize observation time, the positioners need to move simultaneously and reach their targets swiftly. We have previously presented a motion planning method based on a decentralized navigation function for the collision-free coordination of the fiber positioners in DESI. In MOONS, the end effector of each positioner handling the fiber can reach the centre of its neighbours. There is therefore a risk of collision with up to 18 surrounding positioners in the chosen dense hexagonal configuration. Moreover, the length of the second arm of the positioner is almost twice the length of the first one. As a result, the geometry of the potential collision zone between two positioners is not limited to the extremity of their end-effector, but surrounds the second arm. In this paper, we modify the navigation function to take into account the larger collision zone resulting from the extended geometrical shape of the positioners. The proposed navigation function takes into account the configuration of the positioners as well as the constraints on the actuators, such as their maximal velocity and their mechanical clearance. Considering the fact that all the positioners' bases are fixed to the focal plane, collisions can occur locally and the risk of collision is limited to the 18 surrounding positioners. The decentralizing motion planning and trajectory generation takes advantage of this limited number of positioners and the locality of collisions, hence significantly reduces the complexity of the algorithm to a linear order. The linear complexity ensures short computation time. In addition, the time needed to move all the positioners to their targets is independent of the number of positioners. These two key advantages of the chosen decentralization approach turn this method to a promising solution for the collision-free motion-planning problem in the next- generation spectroscopic survey projects. A motion planning simulator, exploited as a software prototype, has been developed in Python. The pre-computed collision-free trajectories of the actuators of all the positioners are fed directly from the simulator to the electronics controlling the motors. A successful demonstration of the effectiveness of these trajectories on the real positioners as well as their simulated counterparts are put side by side in the following online video sequence (https://goo.gl/YuwwsE).

Effect of increased surface hydrophobicity via drug conjugation on the clearance of inhaled PEGylated polylysine dendrimers.

PubMed

Haque, Shadabul; McLeod, Victoria M; Jones, Seth; Fung, Sandy; Whittaker, Michael; McIntosh, Michelle; Pouton, Colin; Owen, David J; Porter, Christopher J H; Kaminskas, Lisa M

2017-10-01

PEGylated polylysine dendrimers are attractive and well tolerated inhalable drug delivery platforms that have the potential to control the release, absorption kinetics and lung retention time of conjugated drugs. The clinical application of these systems though, would likely require partial substitution of surface PEG groups with drug molecules that are anticipated to alter their lung clearance kinetics and clearance pathways. In the current study, we therefore evaluated the impact of increased surface hydrophobicity via substitution of 50% surface PEG groups with a model hydrophobic drug (α-carboxyl OtButylated methotrexate) on the lung clearance of a Generation 5 PEGylated polylysine dendrimer in rats. PEG substitution with OtBu-methotrexate accelerated lung clearance of the dendrimer by increasing polylysine scaffold catabolism, improving systemic absorption of the intact dendrimer and low molecular weight products of scaffold catabolism, and enhancing mucociliary clearance. These results suggest that the conjugation of hydrophobic drug on the surface of a PEGylated dendrimer is likely to accelerate lung clearance when compared to a fully PEGylated dendrimer. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Effect of Turbine Axial Nozzle-Wheel Clearance on Performance of Mark 25 Torpedo Power Plant

NASA Technical Reports Server (NTRS)

Hoyt, Jack W.; Kottas, Harry

1948-01-01

Investigations were made of the turbine from a Mark 25 torpedo to determine the performance of the unit with three different turbine nozzles at various axial nozzle-wheel clearances. Turbine efficiency with a reamed nondivergent nozzle that uses the axial clearance space for gas expansion was little affected by increasing the axial running clearance from 0.030 to 0.150 inch. Turbine efficiency with cast nozzles that expanded the gas inside the nozzle passage was found to be sensitive to increased axial nozzle-wheel clearance. A cast nozzle giving a turbine brake efficiency of 0.525 at an axial running clearance of 0.035 inch gave a brake efficiency of 0.475 when the clearance was increased to 0.095 inch for the same inlet-gas conditions and blade-jet speed ratio. If the basis for computing the isentropic power available to the turbine is the temperature inside the nozzle rather then the temperature in the inlet-gas pipe, an increase in turbine efficiency of about 0.01 is indicated.

Calculation of tip clearance effects in a transonic compressor rotor

NASA Technical Reports Server (NTRS)

Chima, R. V.

1996-01-01

The flow through the tip clearance region of a transonic compressor rotor (NASA rotor 37) was computed and compared to aerodynamic probe and laser anemometer data. Tip clearance effects were modeled both by gridding the clearance gap and by using a simple periodicity model across the ungridded gap. The simple model was run with both the full gap height, and with half the gap height to simulate a vena-contracta effect. Comparisons between computed and measured performance maps and downstream profiles were used to validate the models and to assess the effects of gap height on the simple clearance model. Recommendations were made concerning the use of the simple clearance model. Detailed comparisons were made between the gridded clearance gap solution and the laser anemometer data near the tip at two operating points. The computer results agreed fairly well with the data but overpredicted the extent of the casing separation and underpredicted the wake decay rate. The computations were then used to describe the interaction of the tip vortex, the passage shock, and the casing boundary layer.

77 FR 14770 - Notice of Proposed Information Collection Requests

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-13

... Collection Clearance Division, Privacy, Information and Records Management Services, Office of Management... Collection Clearance Division, Privacy, Information and Records Management Services, Office of Management..., Acting Director, Information Collection Clearance Division, Privacy, Information and Records Management...

Traffic incident management quick clearance laws : a national review of best practices.

DOT National Transportation Integrated Search

2008-12-01

Constituting Quick Clearance Laws, three types of general legislation Move Over, Driver Removal, and Authority Removal laws - support concurrent Quick Clearance operations intended to enhance motorist and responder safety, as well as reduce...

Regional Myocardial Blood Flow*

PubMed Central

Sullivan, Jay M.; Taylor, Warren J.; Elliott, William C.; Gorlin, Richard

1967-01-01

A method is described which measures the local effectiveness of the myocardial circulation, expressed as a clearance constant. Uniform clearance constants have been demonstrated in the normal canine and human myocardium. A distinct difference in clearance constants has been demonstrated between the normal canine myocardium and areas of naturally occurring disease. Heterogeneous clearance constants have been found in a majority of human subjects with coronary artery disease—the lowest rates being noted in areas of fibrous aneurysm. PMID:6036537

Participation of the hypophyseal-adrenal cortex system in thrombin clearance during immobilization stress

NASA Technical Reports Server (NTRS)

Kudryashov, B. A.; Uljanov, A. M.; Shapiro, F. B.; Bazazyan, G. G.

1981-01-01

Thrombin marked with I-131 resulted in a considerable increase of the thrombined clearance rate in healthy male rats during stress caused by an immobilization lasting 30 minutes, and in an increase of thrombin clearance occurred by a combination of immobilization and administration of adrenocorticotropin (ACTH). Contrary to ACTH, the thrombin clearance is not stimulated in healthy animals by hydrocortisone. The results of the examination are presented.

Measurement of Rotating Blade Tip Clearance with Fibre-Optic Probe

NASA Astrophysics Data System (ADS)

Cao, S. Z.; Duan, F. J.; Zhang, Y. G.

2006-10-01

This paper described a tip clearance measuring system with fibre-optic probe. The system is based on a novel tip clearance sensor of optical fibre-bundle mounted on the casing, rotating speed synchronization sensor mounted on the rotating shaft, the tip clearance preamplification processing circuit followed by high speed data-acquisition unit. A novel tip clearance sensor of trifurcated optical fibre bundle was proposed and demonstrated. It is independent of material of measured surface but capacitive probe demands target conductive. Measurements can be taken under severe conditions such as ionization. Sensor circuitry and data acquisition circuit were successfully designed. With the help of Rotation synchronized sensor, all the blades can be detected in real-time. Because of fibre-optic sensor, the measuring system has commendably frequency response, which can work well in high rotating speed from 0-15000rpm.The measurement range of tip clearance is 0-3mm with 25um precision.

Physiological stability and renal clearance of ultrasmall zwitterionic gold nanoparticles: Ligand length matters

NASA Astrophysics Data System (ADS)

Ning, Xuhui; Peng, Chuanqi; Li, Eric S.; Xu, Jing; Vinluan, Rodrigo D.; Yu, Mengxiao; Zheng, Jie

2017-05-01

Efficient renal clearance has been observed from ultrasmall zwitterionic glutathione-coated gold nanoparticles (GS-AuNPs), which have broad preclinical applications in cancer diagnosis and kidney functional imaging. However, origin of such efficient renal clearance is still not clear. Herein, we conducted head-to-head comparison on physiological stability and renal clearance of two zwitterionic luminescent AuNPs coated with cysteine and glycine-cysteine (Cys-AuNPs and Gly-Cys-AuNPs), respectively. While both of them exhibited similar surface charges and the same core sizes, additional glycine slightly increased the hydrodynamic diameter of the AuNPs by 0.4 nm but significantly enhanced physiological stability of the AuNPs as well as altered their clearance pathways. These studies indicate that the ligand length, in addition to surface charges and size, also plays a key role in the physiological stability and renal clearance of ultrasmall zwitterionic inorganic NPs.

Indocyanine green. Its use as an early indicator of hepatic dysfunction following injury in man.

PubMed

Gottlieb, M E; Stratton, H H; Newell, J C; Shah, D M

1984-03-01

To evaluate hepatic function, the kinetics of indocyanine green clearance were studied in seven injured patients with hepatic venous catheters. Indocyanine green clearance after a bolus injection of 20 mg was relatively monoexponential on the first day after injury. Following this, a second slower compartment of indocyanine green clearance was uniformly evident, becoming most prominent around the fourth day after injury. Indocyanine green clearance again became more uniform as recovery continued. Fractional indocyanine green extraction ten minutes after injection decreased from 0.9 on the first day after injury to 0.2 three days later, and then returned to 0.7 on the seventh day after injury. These decreases in indocyanine green clearance preceded an increase in total serum bilirubin concentration to a mean value of 1.9 mg/dL. Indocyanine green clearance was thus found to be an early and sensitive indicator of impaired hepatic function.

Non-invasive Imaging of Sendai Virus Infection in Pharmacologically Immunocompromised Mice: NK and T Cells, but not Neutrophils, Promote Viral Clearance after Therapy with Cyclophosphamide and Dexamethasone

PubMed Central

Mostafa, Heba H.; Vogel, Peter; Srinivasan, Ashok; Russell, Charles J.

2016-01-01

In immunocompromised patients, parainfluenza virus (PIV) infections have an increased potential to spread to the lower respiratory tract (LRT), resulting in increased morbidity and mortality. Understanding the immunologic defects that facilitate viral spread to the LRT will help in developing better management protocols. In this study, we immunosuppressed mice with dexamethasone and/or cyclophosphamide then monitored the spread of viral infection into the LRT by using a noninvasive bioluminescence imaging system and a reporter Sendai virus (murine PIV type 1). Our results show that immunosuppression led to delayed viral clearance and increased viral loads in the lungs. After cessation of cyclophosphamide treatment, viral clearance occurred before the generation of Sendai-specific antibody responses and coincided with rebounds in neutrophils, T lymphocytes, and natural killer (NK) cells. Neutrophil suppression using anti-Ly6G antibody had no effect on infection clearance, NK-cell suppression using anti-NK antibody delayed clearance, and T-cell suppression using anti-CD3 antibody resulted in no clearance (chronic infection). Therapeutic use of hematopoietic growth factors G-CSF and GM-CSF had no effect on clearance of infection. In contrast, treatment with Sendai virus—specific polysera or a monoclonal antibody limited viral spread into the lungs and accelerated clearance. Overall, noninvasive bioluminescence was shown to be a useful tool to study respiratory viral progression, revealing roles for NK and T cells, but not neutrophils, in Sendai virus clearance after treatment with dexamethasone and cyclophosphamide. Virus-specific antibodies appear to have therapeutic potential. PMID:27589232

Effect of neurotrauma on hepatic drug clearance.

PubMed

Boucher, B A; Kuhl, D A; Fabian, T C; Robertson, J T

1991-11-01

Lorazepam, antipyrine, and indocyanine green were administered to 10 patients with severe head injuries as marker substrates of hepatic glucuronidation, oxidation, and hepatic blood flow, respectively. Pharmacokinetic parameter estimates were determined at baseline (20 to 80 hours after injury) and up to three additional times thereafter (study days 4, 7, and 14). Antipyrine clearance was increased significantly from baseline (0.50 +/- 0.31 ml/min/kg) on study days 4, 7, and 14 (p less than 0.0001). Increases in antipyrine clearance from baseline to the last study day were observed in all study patients ranging from 14% to 207%. A significant increase was also observed in lorazepam clearance on study day 14 relative to baseline (1.39 +/- 0.56 ml/min/kg) (p less than 0.005). Increases in lorazepam clearance occurred in seven of nine patients over time ranging from 9% to 130%. The unbound fraction of lorazepam did not change significantly over the study period. Likewise, no significant change was observed in the clearance of indocyanine green over time. Antipyrine clearance and alpha 1-acid glycoprotein (r = 0.41), and lorazepam clearance and C-reactive protein (r = -0.38) were significantly correlated (p less than 0.05). Similarly, antipyrine and lorazepam clearances were significantly correlated with injury severity based on the Acute Physiologic and Chronic Health Evaluation (APACHE II) score (r = -0.43 and r = -0.37, respectively). These findings suggest that hepatic oxidative and conjugative metabolism increase significantly over time in patients after acute head injury. An awareness of the potential for pharmacokinetic alterations in similarly metabolized drugs used for patients with severe head injuries is recommended.

Predicting Human Clearance of OATP substrates using Cynomolgus monkey: In vitro-in vivo scaling of hepatic uptake clearance.

PubMed

de Bruyn, Tom; Ufuk, Ayse; Cantrill, Carina; Kosa, Rachel E; Bi, Yi-An; Niosi, Mark; Modi, Sweta; Rodrigues, A David; Tremaine, Larry M; Varma, Manthena Vs; Galetin, Aleksandra; Houston, J Brian

2018-05-02

This work explores the utility of the cynomolgus monkey as a preclinical model to predict hepatic uptake clearance mediated by organic anion transporting polypeptide (OATP) transporters. Nine OATP substrates (rosuvastatin, pravastatin, repaglinide, fexofenadine, cerivastatin, telmisartan, pitavastatin, bosentan and valsartan) were investigated in plated cynomolgus monkey and human hepatocytes. Total uptake clearance and passive diffusion were measured in vitro from initial rates in the absence and presence of the OATP inhibitor rifamycin SV, respectively. Total uptake clearance values in plated hepatocytes ranged over three orders of magnitude in both species with a similar rank order and good agreement in the relative contribution of active transport to total uptake between cynomolgus monkey and human. In vivo hepatic clearance for these nine drugs was determined in cynomolgus monkey after intravenous dosing. Hepatic clearances showed a similar range to human parameters and good predictions from respective hepatocyte parameters (with 2.7 and 3.8-fold bias on average, respectively). The use of cross species empirical scaling factors (based on either dataset average or individual drug scaling factor from cynomolgus monkey data) improved prediction (less bias, better concordance) of human hepatic clearance from human hepatocyte data alone. In vitro intracellular binding in hepatocytes also correlated well between species. It is concluded that the minimal species differences observed for the current dataset between cynomolgus monkey and human hepatocyte uptake, both in vitro and in vivo, support future use of this preclinical model to delineate drug hepatic uptake and enable prediction of human in vivo intrinsic hepatic clearance. The American Society for Pharmacology and Experimental Therapeutics.

Confusion in Using Pre-Departure Clearances

DOT National Transportation Integrated Search

1996-12-20

In 1990, the FAA implemented the Pre-Departure Clearance (PDC) program at a : number of U.S. airports. This system allows pilots to obtain IFR clearances : through aircraft ACARS units prior to taxi-out, thus eliminating the need for : verbal communi...

[Correlation index amylase-creatinine clearance to endogenous creatinine clearance in severe preeclampsia].

PubMed

Vázquez Rodríguez, Juan Gustavo; Cruz Cruz, Polita del Rocío; Márquez Hubert, Elizabeth

2009-07-01

Tubular lesion may cause acute renal insufficiency in pregnant patients with severe preeclampsia. To describe the correlation between the amylase/creatinine clearance ratio and endogenous creatinine depuration in pregnant patients with severe preeclampsia. Transversal study (pilot study) twenty eight women with pregnancies of 20 to 40 weeks complicated by severe preeclampsia were studied. Subjects had serum and urine creatinine and amylase determinations to calculate the amylase/creatinine clearance ratio (%). According to the results, two groups were formed: group A (> 3%) and group B (< or = 3%). The correlation between amylase/creatinine clearance ratio and endogenous creatinine depuration was evaluated. measures of central tendency and dispersion, Student's t-test, Pearson correlation coefficient (r) and linear regression were used. Group A included 23 cases (82%) and group B included 5 cases (18%). Amylase/creatinine clearance ratio (%) for group A was 5.22 +/- 1.6 and for group B was 2.41 +/- 0.41 (p = 0.001). The endogenous creatinine depuration (mL /min. /1.73 m2 SC) for group A was 105.6 +/- 9.71 and for group B was 132.10 +/- 7.95 (p = 0.54). The r between amylase/creatinine clearance ratio and endogenous creatinine depuration for group A was -0.43 and for group B was -0.25. A moderately significant negative correlation exists between amylase/creatinine clearance ratio and endogenous creatinine depuration.

Dynamic alteration in splenic function during acute falciparum malaria

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

Looareesuwan, S.; Ho, M.; Wattanagoon, Y.

Plasmodium-infected erythrocytes lose their normal deformability and become susceptible to splenic filtration. In animal models, this is one mechanism of antimalarial defense. To assess the effect of acute falciparum malaria on splenic filtration, we measured the clearance of heated /sup 51/Cr-labeled autologous erythrocytes in 25 patients with acute falciparum malaria and in 10 uninfected controls. Two groups of patients could be distinguished. Sixteen patients had splenomegaly, markedly accelerated clearance of the labeled erythrocytes (clearance half-time, 8.4 +/- 4.4 minutes (mean +/- SD) vs. 62.5 +/- 36.5 minutes in controls; P less than 0.001), and a lower mean hematocrit than didmore » the patients without splenomegaly (P less than 0.001). In the nine patients without splenomegaly, clearance was normal. After institution of antimalarial chemotherapy, however, the clearance in this group accelerated to supernormal rates similar to those in the patients with splenomegaly, but without the development of detectable splenomegaly. Clearance was not significantly altered by treatment in the group with splenomegaly. Six weeks later, normal clearance rates were reestablished in most patients in both groups. We conclude that splenic clearance of labeled erythrocytes is enhanced in patients with malaria if splenomegaly is present and is enhanced only after treatment if splenomegaly is absent. Whether this enhanced splenic function applies to parasite-infected erythrocytes in patients with malaria and has any clinical benefit will require further studies.« less

Secretion clearance strategies in Australian and New Zealand Intensive Care Units.

PubMed

Ntoumenopoulos, George; Hammond, Naomi; Watts, Nicola R; Thompson, Kelly; Hanlon, Gabrielle; Paratz, Jennifer D; Thomas, Peter

2017-06-26

To describe the processes of care for secretion clearance in adult, intubated and mechanically ventilated patients in Australian and New Zealand Intensive Care Units (ICUs). A prospective, cross-sectional study was conducted through the Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS CTG) Point Prevalence Program. Forty-seven ICUs collected data from 230 patients intubated and ventilated on the study day. Secretion clearance techniques beyond standard suctioning were used in 84/230 (37%) of patients during the study period. Chest wall vibration 34/84 (40%), manual lung hyperinflation 24/84 (29%), chest wall percussion 20/84 (24%), postural drainage/patient positioning 17/84 (20%) and other techniques including mobilisation 15/84 (18%), were the most common secretion clearance techniques employed. On average (SD), patients received airway suctioning 8.8 (5.0) times during the 24-h study period. Mucus plugging events were infrequent (2.7%). The additional secretion clearance techniques were provided by physiotherapy staff in 24/47 (51%) ICUs and by both nursing and physiotherapy staff in the remaining 23/47 (49%) ICUs. One-third of intubated and ventilated patients received additional secretion clearance techniques. Mucus plugging events were infrequent with these additional secretion clearance approaches. Prospective studies must examine additional secretion clearance practices, prevalence of mucus plugging episodes and impact on patient outcomes. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Differences in amyloid-β clearance across mouse and human blood-brain barrier models: kinetic analysis and mechanistic modeling.

PubMed

Qosa, Hisham; Abuasal, Bilal S; Romero, Ignacio A; Weksler, Babette; Couraud, Pierre-Oliver; Keller, Jeffrey N; Kaddoumi, Amal

2014-04-01

Alzheimer's disease (AD) has a characteristic hallmark of amyloid-β (Aβ) accumulation in the brain. This accumulation of Aβ has been related to its faulty cerebral clearance. Indeed, preclinical studies that used mice to investigate Aβ clearance showed that efflux across blood-brain barrier (BBB) and brain degradation mediate efficient Aβ clearance. However, the contribution of each process to Aβ clearance remains unclear. Moreover, it is still uncertain how species differences between mouse and human could affect Aβ clearance. Here, a modified form of the brain efflux index method was used to estimate the contribution of BBB and brain degradation to Aβ clearance from the brain of wild type mice. We estimated that 62% of intracerebrally injected (125)I-Aβ40 is cleared across BBB while 38% is cleared by brain degradation. Furthermore, in vitro and in silico studies were performed to compare Aβ clearance between mouse and human BBB models. Kinetic studies for Aβ40 disposition in bEnd3 and hCMEC/D3 cells, representative in vitro mouse and human BBB models, respectively, demonstrated 30-fold higher rate of (125)I-Aβ40 uptake and 15-fold higher rate of degradation by bEnd3 compared to hCMEC/D3 cells. Expression studies showed both cells to express different levels of P-glycoprotein and RAGE, while LRP1 levels were comparable. Finally, we established a mechanistic model, which could successfully predict cellular levels of (125)I-Aβ40 and the rate of each process. Established mechanistic model suggested significantly higher rates of Aβ uptake and degradation in bEnd3 cells as rationale for the observed differences in (125)I-Aβ40 disposition between mouse and human BBB models. In conclusion, current study demonstrates the important role of BBB in the clearance of Aβ from the brain. Moreover, it provides insight into the differences between mouse and human BBB with regards to Aβ clearance and offer, for the first time, a mathematical model that describes Aβ clearance across BBB. Copyright © 2014 Elsevier Ltd. All rights reserved.

Differences in amyloid-β clearance across mouse and human blood-brain barrier models: Kinetic analysis and mechanistic modeling

PubMed Central

Qosa, Hisham; Abuasal, Bilal S.; Romero, Ignacio A.; Weksler, Babette; Couraud, Pierre-Oliver; Keller, Jeffrey N.; Kaddoumi, Amal

2014-01-01

Alzheimer’s disease (AD) has a characteristic hallmark of amyloid-β (Aβ) accumulation in the brain. This accumulation of Aβ has been related to its faulty cerebral clearance. Indeed, preclinical studies that used mice to investigate Aβ clearance showed that efflux across blood-brain barrier (BBB) and brain degradation mediate efficient Aβ clearance. However, the contribution of each process to Aβ clearance remains unclear. Moreover, it is still uncertain how species differences between mouse and human could affect Aβ clearance. Here, a modified form of the brain efflux index method was used to estimate the contribution of BBB and brain degradation to Aβ clearance from the brain of wild type mice. We estimated that 62% of intracerebrally injected 125I-Aβ40 is cleared across BBB while 38% is cleared by brain degradation. Furthermore, in vitro and in silico studies were performed to compare Aβ clearance between mouse and human BBB models. Kinetic studies for Aβ40 disposition in bEnd3 and hCMEC/D3 cells, representative in vitro mouse and human BBB models, respectively, demonstrated 30-fold higher rate of 125I-Aβ40 uptake and 15-fold higher rate of degradation by bEnd3 compared to hCMEC/D3 cells. Expression studies showed both cells to express different levels of P-glycoprotein and RAGE, while LRP1 levels were comparable. Finally, we established a mechanistic model, which could successfully predict cellular levels of 125I-Aβ40 and the rate of each process. Established mechanistic model suggested significantly higher rates of Aβ uptake and degradation in bEnd3 cells as rationale for the observed differences in 125I-Aβ40 disposition between mouse and human BBB models. In conclusion, current study demonstrates the important role of BBB in the clearance of Aβ from the brain. Moreover, it provides insight into the differences between mouse and human BBB with regards to Aβ clearance and offer, for the first time, a mathematical model that describes Aβ clearance across BBB. PMID:24467845

Axial compressor blade design for desensitization of aerodynamic performance and stability to tip clearance

NASA Astrophysics Data System (ADS)

Erler, Engin

Tip clearance flow is the flow through the clearance between the rotor blade tip and the shroud of a turbomachine, such as compressors and turbines. This flow is driven by the pressure difference across the blade (aerodynamic loading) in the tip region and is a major source of loss in performance and aerodynamic stability in axial compressors of modern aircraft engines. An increase in tip clearance, either temporary due to differential radial expansion between the blade and the shroud during transient operation or permanent due to engine wear or manufacturing tolerances on small blades, increases tip clearance flow and results in higher fuel consumption and higher risk of engine surge. A compressor design that can reduce the sensitivity of its performance and aerodynamic stability to tip clearance increase would have a major impact on short and long-term engine performance and operating envelope. While much research has been carried out on improving nominal compressor performance, little had been done on desensitization to tip clearance increase beyond isolated observations that certain blade designs such as forward chordwise sweep, seem to be less sensitive to tip clearance size increase. The current project aims to identify through a computational study the flow features and associated mechanisms that reduces sensitivity of axial compressor rotors to tip clearance size and propose blade design strategies that can exploit these results. The methodology starts with the design of a reference conventional axial compressor rotor followed by a parametric study with variations of this reference design through modification of the camber line and of the stacking line of blade profiles along the span. It is noted that a simple desensitization method would be to reduce the aerodynamic loading of the blade tip which would reduce the tip clearance flow and its proportional contribution to performance loss. However, with the larger part of the work on the flow done in this region, this approach would entail a nominal performance penalty. Therefore, the chosen rotor design philosophy aims to keep the spanwise loading constant to avoid trading performance for desensitization. The rotor designs that resulted from this exercise are simulated in ANSYS CFX at different tip clearance sizes. The change in their performance with respect to tip clearance size (sensitivity) is compared both on an integral level in terms of pressure ratio and adiabatic efficiency, as well as on a detailed level in terms of aerodynamic losses and blockage associated with tip clearance flow. The sensitivity of aerodynamic stability is evaluated either directly through the simulations of the rotor characteristics up to the stall point (expensive in time and resources) for a few designs or indirectly through the position of the interface between the incoming and tip clearance flow with respect to the rotor leading edge plane. The latter approach is based on a generally observed stall criteria in modern axial compressors. The rotor designs are then assessed according to their sensitivity in comparison to that of the reference rotor design to detect features that can explain the trend in sensitivity to tip clearance size. These features can then be validated and the associated flow mechanisms explained through numerical simulations and modelling. Analysis of the database from the rotor parametric study shows that the observed trend in sensitivity cannot be explained by the shifting of the aerodynamic loading along the blade chord, as initially hypothesized based on the literature review. Instead, two flow features are found to reduce sensitivity of performance and stability to tip clearance, namely an increase in incoming meridional momentum in the tip region and a reduction/elimination of double leakage flow. Double leakage flow is the flow that exits the tip clearance of one blade and proceeds into the clearance of the adjacent blade rather than convecting downstream out of the local blade passage. These flow features are isolated and validated based on the reference rotor design through changes in the inlet total pressure condition to alter incoming flow momentum and blade number count to change double leakage rate. In terms of flow mechanism, double leakage is shown to be detrimental to performance and stability, and its proportional increase with tip clearance size explains the sensitivity increase in the presence of double leakage and, conversely, the desensitization effect of reducing or eliminating double leakage. The increase in incoming meridional momentum in the tip region reduces sensitivity to tip clearance through its reduction of double leakage as well as through improved mixing with tip clearance flow, as demonstrated by an analytical model without double leakage flow. The above results imply that any blade design strategy that exploits the two desensitizing flow features would reduce the performance and stability sensitivity to tip clearance size. The increase of the incoming meridional momentum can be achieved through forward chordwise sweep of the blade. The reduction of double leakage without changing blade pitch can be obtained by decreasing the blade stagger angle in the tip region. Examples of blade designs associated with these strategies are shown through CFX simulations to be successful in reducing sensitivity to tip clearance size.

AHERA CLEARANCE AT TWENTY ABATEMENT SITES

EPA Science Inventory

A study was conducted during the summer of 1988 to document Asbestos Hazard Emergency Response Act (AHERA) clearance air-sampling practices and clearance concentrations of airborne asbestos at 20 asbestos-abatement sites in New Jersey. Each abatement took place in a school buildi...

AHERA CLEARANCE AT TWENTY ABATEMENT SITES

EPA Science Inventory

A study was conducted during the summer of 1988 to document Asbestos Hazard Emergency Response Act (AHERA) clearance air sampling practices and clearance concentrations of airborne asbestos at 20 asbestos-abatement sites in New Jersey. ach abatement took place in a school buildin...

The effects of topical agents of fluticasone propionate, oxymetazoline, and 3% and 0.9% sodium chloride solutions on mucociliary clearance in the therapy of acute bacterial rhinosinusitis in vivo.

PubMed

Inanli, Selçuk; Oztürk, Ozmen; Korkmaz, Mukadder; Tutkun, Alper; Batman, Cağlar

2002-02-01

The aims of the study were to determine: 1) how mucociliary activity in acute bacterial rhinosinusitis is affected; 2) how this activity is changed by therapy; 3) the effects of topical agents on mucociliary clearance, and 4) the most appropriate topical agent(s) to be used in the therapy of sinusitis. Five groups of patients with acute bacterial rhinosinusitis were studied prospectively. All patients had 500 mg oral amoxicillin and 125 mg oral clavulanic acid preparations given three times daily for 3 weeks. According to the topical agent applications, these groups included: group I (n = 12), no topical treatment was given; group II (n = 14), two puffs for each nostril once daily of 50 microg/100 mL fluticasone propionate was given; group III (n = 9), one puff for each nostril three times daily of 0.05% oxymetazoline was given; group IV (n =12), 3% sodium chloride (NaCl) (buffered to pH 6.5-7 at room temperature) was given; and group V (n =13), 10-mL solutions of 0.9% NaCl (buffered to pH 6.5--7 at room temperature) were given for nasal irrigations three times daily. All patients had medication for 3 weeks and were controlled each week. The saccharin method was used to measure nasal mucociliary clearance. To investigate the early effects of the topical agents for groups II to V, an additional test was repeated 20 minutes after the basal mucociliary clearance recordings. The test was repeated in the first, second, and third weeks of the treatment. The mucociliary clearance was significantly slower in the acute bacterial rhinosinusitis group than in the control group. There was no significant difference between the basal mucociliary clearance and the 20th minute mucociliary clearance of the fluticasone propionate and 0.9% NaCl solution groups. The mean values of the basal and the 20 minute's mucociliary clearance of the oxymetazoline group were 24.72 +/- 6.16 and 15.5 +/- 7.45 minutes, respectively, which were statistically significant. The mean values of the basal and the 20th minute mucociliary clearance of the 3% NaCl solution groups were 19.45 +/- 9.35 and 15.45 +/- 8.20 minutes, respectively, which were also statistically significant. In the first group (without topical treatment), the basal mucociliary clearance became significantly shorter after the second week of treatment. In the first and second weeks of the treatment of the oxymetazoline group, the mucociliary clearance did not change significantly, but after the third week the mucociliary clearance was significantly shorter. In the 3% NaCl solution group, significant improvement began from the first week and continued through the third week. Comparing the basal and the third weeks' mucociliary clearance values among the groups, the oxymetazoline and 3% NaCl solution groups revealed more significant improvement than the other groups, but this improvement was not different from the improvement of group I. There was still a statistically significant difference in the mucociliary clearance of the post-treatment sinusitis groups from the control group. The oxymetazoline and 3% NaCl solution groups seemed to be more effective in mucociliary clearance, but there was no significant difference in improvement among the groups. The improvement of acute bacterial rhinosinusitis takes more than 3 weeks, according to the mucociliary clearance values of the groups.

Phosphate Removal by Peritoneal Dialysis: The Effect of Transporter Status and Peritoneal Dialysis Prescription.

PubMed

Courivaud, Cecile; Davenport, Andrew

2016-01-01

♦ Interventional trials failed to demonstrate that increasing urea clearance improved peritoneal dialysis (PD) patient survival. Hyperphosphatemia is a well-recognized predictor of cardiovascular and all-cause mortality in PD patients. Simplification of PD small solute clearance targets focuses away from larger solutes, including phosphate. In the US and UK, increasing use of automated peritoneal dialysis (APD) cyclers with shorter dwell times could also potentially reduce peritoneal phosphate removal compared to continuous ambulatory peritoneal dialysis (CAPD). ♦ Total phosphate and peritoneal phosphate clearances were measured in a prospective observational cohort of 380 adult PD patients attending a tertiary university hospital between 1996 and 2013 for routine assessment of PD adequacy. ♦ Eighty-seven patients (22.9%) were hyperphosphatemic. Taking the mean 4-hour dialysate to plasma (D/P) ratio for phosphate, 193 (50.8%) were fast and fast-average transporters and 187 (49.2%) were slow and slow-average transporters (compared to 276 [72.6%] and 104 [27.4%], respectively, for peritoneal creatinine transporter status). Faster peritoneal phosphate transporter status was associated with over-hydration (odds ratio [OR] = 2.45 [1.43 - 4.20], p = 0.001). Whereas the 4-hour D/P creatinine and peritoneal weekly creatinine clearance did not differ between those who were hyperphosphatemic or not, the hyperphosphatemic patients had lower 4-hour D/P phosphate and lower peritoneal weekly phosphate clearance (p = 0.019, and p = 0.06 respectively). We found greater peritoneal phosphate clearance for patients choosing CAPD compared to APD, irrespective of the peritoneal phosphate transporter status. ♦ Peritoneal creatinine transporter status and creatinine clearance cannot be used as surrogate markers of peritoneal phosphate transport and clearance. Hyperphosphatemia was more common in PD patients with slower peritoneal transporter status and lower peritoneal phosphate clearance. Greater peritoneal phosphate clearance was achieved with CAPD prescriptions. Slower peritoneal transporters should be advised to choose CAPD to improve serum phosphate control. Copyright © 2016 International Society for Peritoneal Dialysis.

Phosphate Removal by Peritoneal Dialysis: The Effect of Transporter Status and Peritoneal Dialysis Prescription

PubMed Central

Courivaud, Cecile; Davenport, Andrew

2016-01-01

♦ Background: Interventional trials failed to demonstrate that increasing urea clearance improved peritoneal dialysis (PD) patient survival. Hyperphosphatemia is a well-recognized predictor of cardiovascular and all-cause mortality in PD patients. Simplification of PD small solute clearance targets focuses away from larger solutes, including phosphate. In the US and UK, increasing use of automated peritoneal dialysis (APD) cyclers with shorter dwell times could also potentially reduce peritoneal phosphate removal compared to continuous ambulatory peritoneal dialysis (CAPD). ♦ Methods: Total phosphate and peritoneal phosphate clearances were measured in a prospective observational cohort of 380 adult PD patients attending a tertiary university hospital between 1996 and 2013 for routine assessment of PD adequacy. ♦ Results: Eighty-seven patients (22.9%) were hyperphosphatemic. Taking the mean 4-hour dialysate to plasma (D/P) ratio for phosphate, 193 (50.8%) were fast and fast-average transporters and 187 (49.2%) were slow and slow-average transporters (compared to 276 [72.6%] and 104 [27.4%], respectively, for peritoneal creatinine transporter status). Faster peritoneal phosphate transporter status was associated with over-hydration (odds ratio [OR] = 2.45 [1.43 – 4.20], p = 0.001). Whereas the 4-hour D/P creatinine and peritoneal weekly creatinine clearance did not differ between those who were hyperphosphatemic or not, the hyperphosphatemic patients had lower 4-hour D/P phosphate and lower peritoneal weekly phosphate clearance (p = 0.019, and p = 0.06 respectively). We found greater peritoneal phosphate clearance for patients choosing CAPD compared to APD, irrespective of the peritoneal phosphate transporter status. ♦ Conclusion: Peritoneal creatinine transporter status and creatinine clearance cannot be used as surrogate markers of peritoneal phosphate transport and clearance. Hyperphosphatemia was more common in PD patients with slower peritoneal transporter status and lower peritoneal phosphate clearance. Greater peritoneal phosphate clearance was achieved with CAPD prescriptions. Slower peritoneal transporters should be advised to choose CAPD to improve serum phosphate control. PMID:26224788

Assessment of kidney function in children by enzymatic determination of 2- or 24-h creatinine clearance: comparison with inulin clearance.

PubMed

Uemura, Osamu; Nagai, Takuhito; Yamakawa, Satoshi; Kaneko, Tetsuji; Hibi, Yoshiko; Yamasaki, Yasuhito; Yamamoto, Masaki; Nakano, Masaru; Iwata, Naoyuki; Hibino, Satoshi

2016-06-01

Although renal inulin clearance (Cin) is the gold standard for evaluation of kidney function, it cannot be measured easily. Therefore, creatinine clearance (Ccr) is often used clinically to evaluate kidney function. Enzymatically measured Ccr was recently found to be much higher than Cin because of the tubular secretion of creatinine (Cr). This study compared three measures of renal clearance, inulin, 2-h Ccr, and 24-h Ccr, in children. Kidney function was evaluated in 76 children (51 males and 25 females) aged 1 month to 18 years with chronic kidney disease (CKD) by three renal clearance methods at almost the same time. Correlations between each pair of three renal clearance measurements were determined. Approximate glomerular filtration rate (GFR) was equal to 62 % of 2-h Ccr or 76 % of 24-h Ccr. Cr secretion by renal tubules was approximately 50 % of the GFR. In this study, we indicate that the measurements of 2-h Ccr or 24-h Ccr do not show true GFR but we could infer approximate GFR from the values. The use of 2- or 24-h Ccr might contribute to the treatment of pediatric CKD patients.

The tear turnover and tear clearance tests - a review.

PubMed

Garaszczuk, Izabela K; Montes Mico, Robert; Iskander, D Robert; Expósito, Alejandro Cerviño

2018-03-01

The aim is to provide a summary of methods available for the assessment of tear turnover and tear clearance rates. The review defines tear clearance and tear turnover and describes their implication for ocular surface health. Additionally, it describes main types of techniques for measuring tear turnover, including fluorescein tear clearance tests, techniques utilizing electromagnetic spectrum and tracer molecule and novel experimental techniques utilizing optical coherence tomography and fluorescein profilometry. Areas covered: Internet databases (PubMed, Science Direct, Google Scholar) and most frequently cited references were used as a principal resource of information on tear turnover rate and tear clearance rate, presenting methodologies and equipment, as well as their definition and implications for the anterior eye surface health and function. Keywords used for data-search were as follows: tear turnover, tear clearance, fluorescein clearance, scintigraphy, fluorophotometry, tear flow, drainage, tear meniscus dynamics, Krehbiel flow and lacrimal functional unit. Expert commentary: After decades, the topic of tear turnover assessment has been reintroduced. Recently, new techniques have been developed to propose less invasive, less time consuming and simpler methodologies for the assessment of tear dynamics that have the potential to be utilized in clinical practice.

Deformation Analysis of the Main Components in a Single Screw Compressor

NASA Astrophysics Data System (ADS)

Liu, Feilong; Liao, Xueli; Feng, Quanke; Van Den Broek, Martijn; De Paepe, Michel

2015-08-01

The single screw compressor is used in many fields such as air compression, chemical industry and refrigeration. During operation, different gas pressures and temperatures applied on the components can cause different degrees of deformation, which leads to a difference between the thermally induced clearance and the designed clearance. However, limited research about clearance design is reported. In this paper, a temperature measurement instrument and a convective heat transfer model were described and used to establish the temperature of a single screw air compressor's casing, screw rotor and star wheel. 3-D models of these three main components were built. The gas force deformation, thermal- structure deformation and thermal-force coupling deformation were carried out by using a finite element simulation method. Results show that the clearance between the bottom of the groove and the top of star wheel is reduced by 0.066 mm, the clearance between the side of groove and the star wheel is reduced by 0.015 mm, and the clearance between the cylinder and the rotor is reduced by 0.01 mm. It is suggested that these deformations should be taken into account during the design of these clearances.

Agalsidase Benefits Renal Histology in Young Patients with Fabry Disease

PubMed Central

Bostad, Leif; Larsen, Kristin Kampevold; Hirth, Asle; Vikse, Bjørn Egil; Houge, Gunnar; Svarstad, Einar

2012-01-01

The effect of early-onset enzyme replacement therapy on renal morphologic features in Fabry disease is largely unknown. Here, we evaluated the effect of 5 years of treatment with agalsidase alfa or agalsidase beta in 12 consecutive patients age 7–33 years (median age, 16.5 years). We performed renal biopsies at baseline and after 5 years of enzyme replacement therapy; 7 patients had additional biopsies after 1 and 3 years. After a median of 65 months, biopsy findings from all patients showed total clearance of glomerular endothelial and mesangial cell inclusions, and findings from 2 patients showed complete clearance of inclusions from epithelial cells of the distal tubule. The 4 patients who received the highest dose of agalsidase exhibited substantial clearance of podocyte inclusions, and the youngest patient had nearly complete clearance of these inclusions. Linear regression analysis showed a highly significant correlation between podocyte globotriaocylceramide clearance and cumulative agalsidase dose (r=0.804; P=0.002). Microalbuminuria normalized in five patients. In summary, long-term enzyme replacement therapy in young patients can result in complete globotriaocylceramide clearance of mesangial and glomerular endothelial cells across all dosage regimens, and clearance of podocyte inclusions is dose-dependent. PMID:23274955

UXO clearance operation in Laos

NASA Astrophysics Data System (ADS)

Sato, Motoyuki; Kadoya, Yoshihiko

2018-04-01

Laos is one of the most seriously contaminated countries by UXO. Most of the UXO are cluster bombs, used in 1960- 70's. There is historical political background about the UXO problems in Laos. Currently, The clearance of UXO is significantly important for future economic development for Laos. It affects not only local inhabitants, but it will affects national economy. For example, UXO clearance in mountainous area can promote construction of roads, and Laos has a good possibility to be the center of transportation in Indo-Chia region. We have started a research project for evaluation of impact of UXO clearance in Laos, "The economic impact and the technological development for the elimination of unexploded ordnance (UXO) elimination in Laos". Lao National Unexploded Ordnance Programme (UXO Lao) is working in the nine most impacted provinces nationwide and it clears land for agriculture and community purposes. We recently visited Laos and observed the UXO clearance procedure conducted by UXOLAO. The technical survey for UXO clearance site to determine for operation, UXO detection by using metal detectors are organized by UXO Lao. In this paper, we will report the technical aspects of the UXO clearance in Laos.

Genome-wide study of methotrexate clearance replicates SLCO1B1

PubMed Central

Ramsey, Laura B.; Panetta, John C.; Smith, Colton; Yang, Wenjian; Fan, Yiping; Winick, Naomi J.; Martin, Paul L.; Cheng, Cheng; Devidas, Meenakshi; Pui, Ching-Hon; Evans, William E.; Hunger, Stephen P.; Loh, Mignon

2013-01-01

Methotrexate clearance can influence the cure of and toxicity in children with acute lymphoblastic leukemia (ALL). We estimated methotrexate plasma clearance for 1279 patients with ALL treated with methotrexate (24-hour infusion of a 1 g/m2 dose or 4-hour infusion of a 2 g/m2 dose) on the Children's Oncology Group P9904 and P9905 protocols. Methotrexate clearance was lower in older children (P = 7 × 10−7), girls (P = 2.7 × 10−4), and those who received a delayed-intensification phase (P = .0022). A genome-wide analysis showed that methotrexate clearance was associated with polymorphisms in the organic anion transporter gene SLCO1B1 (P = 2.1 × 10−11). This replicates findings using different schedules of high-dose methotrexate in St Jude ALL treatment protocols; a combined meta-analysis yields a P value of 5.7 × 10−19 for the association of methotrexate clearance with SLCO1B1 SNP rs4149056. Validation of this variant with 5 different treatment regimens of methotrexate solidifies the robustness of this pharmacogenomic determinant of methotrexate clearance. This study is registered at http://www.clinicaltrials.gov as NCT00005585 and NCT00005596. PMID:23233662

Radial Clearance Found To Play a Key Role in the Performance of Compliant Foil Air Bearings

NASA Technical Reports Server (NTRS)

Radil, Kevin C.

2003-01-01

Compliant foil air bearings are at the forefront of the Oil-Free turbomachinery revolution, which supports gas turbine engines with hydrodynamic bearings that use air instead of oil as the working fluid. These types of bearings have been around for almost 50 years and have found a home in several commercial applications, such as in air cycle machines, turbocompressors, and microturbines, but are now being aggressively pursued for use in small and midrange aircraft gas turbine engines. Benefits include higher operating speeds and temperatures, lower maintenance costs, and greater reliability. The Oil-Free Turbomachinery team at the NASA Glenn Research Center is working to foster the transition of Oil-Free technology into gas turbine engines by performing in-house experiments on foil air bearings in order to gain a greater insight into their complex operating principles. A research program recently undertaken at Glenn focused on the concept of radial clearance and its influence on bearing performance. The tests were conducted on foil bearings with different radial clearances. As defined for a foil bearing, radial clearance is a measure of the small amount of shaft radial motion that is present from play that exists in the elastic support structure, such as between the top and bump foils and the bump foils and bearing shell (see the drawing). With an insufficient amount of radial clearance, the bearing imparts a high preload on the shaft, which when excessive, can reduce the loadcarrying capability of the bearing. On the other hand, systems using foil bearings with excessive radial clearance may experience rotordynamic instabilities because of low bearing preload. Therefore, without a more thorough understanding of radial clearance, it is difficult to accurately predict the performance of a given bearing design. The test program demonstrated that there is a direct correlation between radial clearance and the performance of foil air bearings. As shown in the graph, an optimum radial clearance exists that will maximize the amount of load that the bearing is capable of supporting. With respect to this optimum, two different performance regimes were observed that are a function of the amount of radial clearance. Tests showed that bearings with radial clearances below the optimum in regime I were susceptible to sudden seizure, a failure mode indicative of thermal runaway caused by high preload. The high preload is in response to an insufficient amount of radial clearance available to accommodate the thermal growth of the bearing and shaft. However, radial clearances greater than the optimum in regime II resulted in low bearing preloads that did not cause any heat-related problems, and the failure mode was due to fluid-film breakdown. In fact, bearings operating with radial clearances twice as much as the optimum suffered a decrease in the maximum load capacity of only about 20 percent. Therefore, special attention has to be given to the range of operating conditions expected in the bearing/shaft system since changes in temperature, centrifugal, and hydrodynamic effects can all affect radial clearance. This enhanced understanding of foil air bearing behavior will greatly aid our efforts to transition Oil-Free technology to future aircraft engines.

15 CFR 752.15 - Export clearance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Export clearance. 752.15 Section 752... OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL COMPREHENSIVE LICENSE § 752.15 Export clearance. (a) Shipper's Export Declaration (SED) or Automated Export...

75 FR 57829 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-22

... Information Collection Clearance Officer, IT Enterprises Business Services Division, AES-200. [FR Doc. 2010... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of Information Collection: Commuter...

76 FR 28500 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-17

... Information Collection Clearance Officer, IT Enterprises Business Services Division, AES-200. [FR Doc. 2011... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of Information Collection: Agricultural...

76 FR 45645 - 10-Day Notice of Proposed Information Collection: Technology Security/Clearance Plans, Screening...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-29

...: Technology Security/Clearance Plans, Screening Records, and Non-Disclosure Agreements ACTION: Notice of... Information Collection: Technology Security/ Clearance Plans, Screening Records, and Non-Disclosure Agreements...: None. Respondents: Business and Nonprofit Organizations, Foreign Governments. Estimated Number of...

32 CFR 154.77 - Reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... took the action, using the enclosed format: (1) Number of Top Secret, Secret, and Confidential clearances issued; (2) Number of Top Secret, Secret, and Confidential clearances denied; (3) Number of Top...) Total number of personnel holding a clearance for Top Secret, Secret, Confidential and Sensitive...

19 CFR 4.61 - Requirements for clearance.

Code of Federal Regulations, 2010 CFR

2010-04-01

... transported in-bond, or when they have unentered foreign merchandise aboard. For the purposes of the vessel clearance requirements, merchandise transported in-bond does not include bonded ship's stores or supplies. While American vessels transporting unentered foreign merchandise must fully comply with usual clearance...

48 CFR 952.204-73 - Facility clearance.

Code of Federal Regulations, 2014 CFR

2014-10-01

....204-73 Section 952.204-73 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CLAUSES AND... granted by the Secretary of Energy. In addition, a Facility Clearance and foreign ownership, control and... Department of Energy Facility Clearance generally need not resubmit the following foreign ownership...

48 CFR 952.204-73 - Facility clearance.

Code of Federal Regulations, 2011 CFR

2011-10-01

....204-73 Section 952.204-73 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CLAUSES AND... granted by the Secretary of Energy. In addition, a Facility Clearance and foreign ownership, control and... Department of Energy Facility Clearance generally need not resubmit the following foreign ownership...

48 CFR 952.204-73 - Facility clearance.

Code of Federal Regulations, 2012 CFR

2012-10-01

....204-73 Section 952.204-73 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CLAUSES AND... granted by the Secretary of Energy. In addition, a Facility Clearance and foreign ownership, control and... Department of Energy Facility Clearance generally need not resubmit the following foreign ownership...

48 CFR 952.204-73 - Facility clearance.

Code of Federal Regulations, 2013 CFR

2013-10-01

....204-73 Section 952.204-73 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CLAUSES AND... granted by the Secretary of Energy. In addition, a Facility Clearance and foreign ownership, control and... Department of Energy Facility Clearance generally need not resubmit the following foreign ownership...

48 CFR 952.204-73 - Facility clearance.

Code of Federal Regulations, 2010 CFR

2010-10-01

....204-73 Section 952.204-73 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CLAUSES AND... granted by the Secretary of Energy. In addition, a Facility Clearance and foreign ownership, control and... Department of Energy Facility Clearance generally need not resubmit the following foreign ownership...

Test Rig for Active Turbine Blade Tip Clearance Control Concepts: An Update

NASA Technical Reports Server (NTRS)

Taylor, Shawn; Steinetz, Bruce; Oswald, Jay; DeCastro, Jonathan; Melcher, Kevin

2006-01-01

The objective is to develop and demonstrate a fast-acting active clearance control system to improve turbine engine performance, reduce emissions, and increase service life. System studies have shown the benefits of reducing blade tip clearances in modern turbine engines. Minimizing blade tip clearances throughout the engine will contribute materially to meeting NASA's Ultra-Efficient Engine Technology (UEET) turbine engine project goals. NASA GRC is examining two candidate approaches including rub-avoidance and regeneration which are explained in subsequent slides.

Adequacy of peritoneal dialysis: beyond small solute clearance.

PubMed

Goldberg, Ryan; Yalavarthy, Rajesh; Teitelbaum, Isaac

2009-01-01

Peritoneal dialysis adequacy is monitored primarily by indices of small solute clearance, Kt/V(urea) and creatinine clearance (C(cr)). Once a threshold of adequacy has been obtained, however, increasing small solute clearance does not result in improved long-term outcomes of PD patients. There are several other factors that may affect optimal dialysis outcomes. These include, but are not limited to: ultrafiltration, inflammation, malnutrition, and mineral metabolism. In this article, we will briefly review data regarding the relationships between these factors and survival on PD.

Plasma interferon-gamma-inducible protein-10 (IP-10) levels during acute hepatitis C virus infection

PubMed Central

Grebely, Jason; Feld, Jordan J.; Applegate, Tanya; Matthews, Gail V.; Hellard, Margaret; Sherker, Alana; Petoumenos, Kathy; Zang, Geng; Shaw, Ineke; Yeung, Barbara; George, Jacob; Teutsch, Suzy; Kaldor, John M.; Cherepanov, Vera; Bruneau, Julie; Shoukry, Naglaa H.; Lloyd, Andrew R.; Dore, Gregory J.

2013-01-01

Systemic levels of interferon-gamma-inducible protein-10 (IP-10) are predictive of treatment-induced clearance in chronic HCV. In the present study, factors associated with plasma IP-10 levels at the time of acute HCV detection and the association between IP-10 levels and spontaneous clearance were assessed in three cohorts of acute HCV infection. Among 300 individuals, 245 (181 male, 47 HIV+) were HCV RNA+ at acute HCV detection. In adjusted analysis, factors independently associated with IP-10 levels ≥150 pg/mL (median level) included HCV RNA levels >6 log IU/mL, HIV co-infection and non-Aboriginal ethnicity. Among 245 HCV RNA+ at acute HCV detection, 214 were untreated (n=137) or had persistent infection (infection duration ≥26 weeks) at treatment initiation (n=77). Spontaneous clearance occurred in 14% (29 of 214). Individuals without spontaneous clearance had significantly higher mean plasma IP-10 levels at the time of acute HCV detection than those with clearance (248±32 vs. 142±22 pg/mL, P=0.008). The proportion of individuals with spontaneous clearance was 0% (0 of 22, P=0.048) and 16% (27 of 165) and in those in those with and without plasma IP-10 levels ≥380 pg/mL. In adjusted analyses, favourable IL28B genotype was associated with spontaneous clearance, while higher HCV RNA level was independently associated with lower odds of spontaneous clearance. Conclusion High IP-10 levels at acute HCV detection were associated with failure to spontaneously clear HCV. Patients with acute HCV and high baseline IP-10 levels, particularly >380 pg/mL, should be considered for early therapeutic intervention, and those with low levels should defer therapy for potential spontaneous clearance. PMID:23325615

Duration and clearance of anal human papillomavirus (HPV) infection among women: the Hawaii HPV cohort study.

PubMed

Shvetsov, Yurii B; Hernandez, Brenda Y; McDuffie, Katharine; Wilkens, Lynne R; Zhu, Xuemei; Ning, Lily; Killeen, Jeffrey; Kamemoto, Lori; Goodman, Marc T

2009-03-01

The association of anal cancer with human papillomavirus (HPV) infection is well established; however, little is known about the epidemiology of anal HPV in healthy women. We investigated patterns of duration and clearance of anal HPV infection in a cohort of healthy women in Hawaii. Viral and nonviral determinants of anal HPV clearance were examined in a longitudinal cohort study of 431 sexually active women. At baseline and at 4-month intervals, interviews were conducted and cervical and anal cell specimens were obtained for detection of HPV DNA. Of the 431 women, 50% experienced a total of 414 incident anal HPV infections, reported at 1 clinic visits from baseline through a follow-up period of average duration of 1.2 years. Of these infections, 58% cleared during follow-up. The clearance rate for a high-risk anal infection was 9.2 per 100 woman-months (95% confidence interval [CI], 6.9-11.9 per 100 woman-months), with a median duration of 150 days (95% CI, 132-243 days). The slowest clearing high-risk HPV types were HPV-59 (median clearance time, 350 days) and HPV-58 (median clearance time, 252 days). The median clearance times for HPV-16 and HPV-18, the predominant types associated with anal cancer, were 132 days and 212 days, respectively. Nonviral factors that delayed clearance of anal HPV included douching, long-term tobacco smoking, and anal sex. The majority of anal HPV infections resolve in a relatively short time. Although anal HPV is commonly acquired in healthy women, its rapid clearance suggests limited efficacy of HPV testing as an anal cancer screening tool.

Pharmacokinetics of paracetamol and its metabolites in women at delivery and post‐partum

PubMed Central

Kulo, Aida; Peeters, Mariska Y.; Allegaert, Karel; Smits, Anne; de Hoon, Jan; Verbesselt, Rene; Lewi, Liesbeth; van de Velde, Marc; Knibbe, Catherijne A. J.

2013-01-01

Aim A recent report on intravenous (i.v.) paracetamol pharmacokinetics (PK) showed a higher total clearance in women at delivery compared with non‐pregnant women. To describe the paracetamol metabolic and elimination routes involved in this increase in clearance, we performed a population PK analysis in women at delivery and post‐partum in which the different pathways were considered. Methods Population PK parameters using non‐linear mixed effect modelling were estimated in a two‐period PK study in women to whom i.v. paracetamol (2 g loading dose followed by 1 g every 6 h up to 24 h) was administered immediately following Caesarean delivery and in a subgroup of the same women to whom single 2 g i.v.loading dose was administered 10–15 weeks post‐partum. Results Population PK analysis was performed based on 255 plasma and 71 urine samples collected in 39 women at delivery and in eight of these 39 women 12 weeks post‐partum. Total clearance was higher in women at delivery compared with 12th post‐partum week (21.1 vs. 11.7 l h−1) due to higher clearances to paracetamol glucuronide (11.6 vs. 4.76 l h−1), to oxidative metabolites (4.95 vs. 2.77 l h−1) and of unchanged paracetamol (1.15 vs. 0.75 l h−1). In contrast, there was no difference in clearance to paracetamol sulphate. Conclusion The increased total paracetamol clearance at delivery is caused by a disproportional increase in glucuronidation clearance and a proportional increase in clearance of unchanged paracetamol and in oxidation clearance, of which the latter may potentially limit further dose increase in this patient group. PMID:22845052

Evaluating the Use of Antibody Variable Region (Fv) Charge as a Risk Assessment Tool for Predicting Typical Cynomolgus Monkey Pharmacokinetics*

PubMed Central

Bumbaca Yadav, Daniela; Sharma, Vikas K.; Boswell, Charles Andrew; Hotzel, Isidro; Tesar, Devin; Shang, Yonglei; Ying, Yong; Fischer, Saloumeh K.; Grogan, Jane L.; Chiang, Eugene Y.; Urban, Konnie; Ulufatu, Sheila; Khawli, Leslie A.; Prabhu, Saileta; Joseph, Sean; Kelley, Robert F.

2015-01-01

The pharmacokinetic (PK) behavior of monoclonal antibodies in cynomolgus monkeys (cynos) is generally translatable to that in humans. Unfortunately, about 39% of the antibodies evaluated for PKs in cynos have fast nonspecific (or non-target-mediated) clearance (in-house data). An empirical model relating variable region (Fv) charge and hydrophobicity to cyno nonspecific clearance was developed to gauge the risk an antibody would have for fast nonspecific clearance in the monkey. The purpose of this study was to evaluate the predictability of this empirical model on cyno nonspecific clearance with antibodies specifically engineered to have either high or low Fv charge. These amino acid changes were made in the Fv region of two test antibodies, humAb4D5-8 and anti-lymphotoxin α. The humAb4D5-8 has a typical nonspecific clearance in cynos, and by making it more positively charged, the antibody acquires fast nonspecific clearance, and making it less positively charged did not impact its clearance. Anti-lymphotoxin α has fast nonspecific clearance in cynos, and making it more positively charged caused it to clear even faster, whereas making it less positively charged caused it to clear slower and within the typical range. These trends in clearance were also observed in two other preclinical species, mice and rats. The effect of modifying Fv charge on subcutaneous bioavailability was also examined, and in general bioavailability was inversely related to the direction of the Fv charge change. Thus, modifying Fv charge appears to impact antibody PKs, and the changes tended to correlate with those predicted by the empirical model. PMID:26491012

Dexmedetomidine metabolic clearance is not affected by fat mass in obese patients.

PubMed

Rolle, A; Paredes, S; Cortínez, L I; Anderson, B J; Quezada, N; Solari, S; Allende, F; Torres, J; Cabrera, D; Contreras, V; Carmona, J; Ramírez, C; Oliveros, A M; Ibacache, M

2018-05-01

Obesity has been associated with reduced dexmedetomidine clearance, suggesting impaired hepatic function or reduced hepatic blood flow. The aim of this study was to clarify the effect of obesity in dexmedetomidine metabolic clearance. Forty patients, ASA I-III, 18-60 yr old, weighing 47-126 kg, scheduled for abdominal laparoscopic surgery, were enrolled. Anaesthetic agents (propofol, remifentanil, and dexmedetomidine) were dosed based on lean body weight measured by dual X-ray absorptiometry. Serial venous samples were drawn during and after dexmedetomidine infusion. A pharmacokinetic analysis was undertaken using non-linear mixed-effect models. In the modelling approach, the total body weight, lean body weight, and adjusted body weight were first tested as size descriptors for volumes and clearances. Hepatic blood flow, liver histopathology, liver enzymes, and gene expression of metabolic enzymes (UGT2B10 and UGT1A4) were tested as covariates of dexmedetomidine metabolic clearance. A decrease in NONMEM objective function value (ΔOFV) of 3.84 points, for an added parameter, was considered significant at the 0.05 level. A total of 637 dexmedetomidine serum samples were obtained. A two-compartmental model scaled to measured lean weight adequately described the dexmedetomidine pharmacokinetics. Liver blood flow was a covariate for dexmedetomidine clearance (ΔOFV=-5.878). Other factors, including fat mass, histopathological damage, and differential expression of enzymes, did not affect the dexmedetomidine clearance in the population studied (ΔOFV<3.84). We did not find a negative influence of obesity in dexmedetomidine clearance when doses were adjusted to lean body weight. Liver blood flow showed a significant effect on dexmedetomidine clearance. NCT02557867. Copyright © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

Higher serum levels of uric acid are associated with a reduced insulin clearance in non-diabetic individuals.

PubMed

Fiorentino, Teresa Vanessa; Sesti, Franz; Succurro, Elena; Pedace, Elisabetta; Andreozzi, Francesco; Sciacqua, Angela; Hribal, Marta Letizia; Perticone, Francesco; Sesti, Giorgio

2018-05-17

Decreased insulin clearance has been reported to be associated with insulin resistance-related disorders and incident type 2 diabetes. The aim of this study was to evaluate whether higher levels of uric acid (UA), a known risk factor of type 2 diabetes, are associated with a reduced insulin clearance. 440 non-diabetic individuals were stratified in tertiles according to serum UA levels. Insulin clearance and skeletal muscle insulin sensitivity were assessed by euglycemic hyperinsulinemic clamp. Hepatic insulin resistance was estimated by the liver IR index. Subjects with higher levels of UA displayed an unfavorable metabolic phenotype with a worse lipid profile, increased levels of 2-h post-load glucose levels, fasting, and 2-h post-load insulin levels, hsCRP, liver IR index, and lower levels of eGFR and skeletal muscle insulin sensitivity, in comparison to individuals with lower UA levels. Moreover, subjects with higher UA concentrations exhibited decreased levels of insulin clearance even after adjustment for age, gender, BMI, eGFR, and skeletal muscle insulin sensitivity. In a multivariate regression analysis model including several confounding factors, UA concentration was an independent predictor of insulin clearance (β = - 0.145; P = 0.03). However, when liver IR index was included in the model, the independent association between UA levels and insulin clearance was not retained. Accordingly, in a mediation analysis, liver IR index was a mediator of the negative effects of UA levels on insulin clearance (t = - 2.55, P = 0.01). Higher serum levels of UA may affect insulin clearance by impairing hepatic insulin sensitivity.

Compressor airfoil tip clearance optimization system

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

Little, David A.; Pu, Zhengxiang

2015-08-18

A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary.more » During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.« less

78 FR 74175 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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76 FR 77835 - Agency Forms Undergoing Paperwork Reduction Act Review

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2011-12-14

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78 FR 76849 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-19

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19 CFR 122.77 - Clearance certificate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Clearance certificate. 122.77 Section 122.77 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Documents Required for Clearance and Permission To Depart; Electronic...

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2011-07-29

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Reduced erythrocyte susceptibility and increased host clearance of young parasites slows Plasmodium growth in a murine model of severe malaria

NASA Astrophysics Data System (ADS)

Khoury, David S.; Cromer, Deborah; Best, Shannon E.; James, Kylie R.; Sebina, Ismail; Haque, Ashraful; Davenport, Miles P.

2015-05-01

The best correlate of malaria severity in human Plasmodium falciparum (Pf) infection is the total parasite load. Pf-infected humans could control parasite loads by two mechanisms, either decreasing parasite multiplication, or increasing parasite clearance. However, few studies have directly measured these two mechanisms in vivo. Here, we have directly quantified host clearance of parasites during Plasmodium infection in mice. We transferred labelled red blood cells (RBCs) from Plasmodium infected donors into uninfected and infected recipients, and tracked the fate of donor parasites by frequent blood sampling. We then applied age-based mathematical models to characterise parasite clearance in the recipient mice. Our analyses revealed an increased clearance of parasites in infected animals, particularly parasites of a younger developmental stage. However, the major decrease in parasite multiplication in infected mice was not mediated by increased clearance alone, but was accompanied by a significant reduction in the susceptibility of RBCs to parasitisation.

Clearance Properties of Nano-sized Particles and Molecules as Imaging Agents: Considerations and Caveats

PubMed Central

Longmire, Michelle; Choyke, Peter L.; Kobayashi, Hisataka

2009-01-01

Summary Nanoparticles possess enormous potential as diagnostic imaging agents and hold promise for the development of multimodality agents with both imaging and therapeutic capabilities. Yet, some of the most promising nanoparticles demonstrate prolonged tissue retention and contain heavy metals. This presents serious concerns for toxicity. The creation of nanoparticles with optimal clearance characteristics will minimize toxicity risks by reducing the duration of exposure to these agents. Given that many nanoparticles possess easily modifiable surface and interior chemistry, if nanoparticle characteristics associated with optimal clearance from the body were well established, it would be feasible to design and create agents with more favorable clearance properties. This paper presents a thorough discussion of the physiologic aspects of nanoparticle clearance, focusing on renal mechanisms, as well as provides an overview of current research investigating clearance of specific types of nanoparticles and nano-sized macromolecules, including dendrimers, quantum dots, liposomes and carbon, gold, and silica-based nanoparticles. PMID:18817471

Influence of blade tip rounding on tip leakage vortex cavitation of axial flow pump

NASA Astrophysics Data System (ADS)

Wu, S. Q.; Shi, W. D.; Zhang, D. S.; Yao, J.; Cheng, C.

2013-12-01

Tip leakage flow in axial flow pumps is mainly caused by the tip clearance, which is the main cause of tip leakage vortex cavitation and blade tip cavitation erosion. In order to improve tip clearance flow and reduce TLV cavitation, four schemes were adopted to the round blade tip. These are: no tip rounding, one time tip clearance tip rounding, two times tip clearance tip rounding, four times tip clearance tip rounding. Using SST k-ω turbulence model and Zwart cavitation model in CFX software, this simulation obtained four kinds of inner flow field results. The numerical results indicated that with the increase of r*, NPSHc gradually increased and the cavitation performance reduced. However, corner vortex was eliminated so that cavitation in gap was restrained. But TLV vorticity increased and cavitation's range here had a little expansion. Combined with the research of this paper and the different analyses of four schemes, we recommend adopting the two times of the tip clearance rounding.

The role of lectins and glycans in platelet clearance

PubMed Central

Hoffmeister, Karin M.

2015-01-01

Summary In recent years, it has become increasingly apparent that the life span of transfused platelets in circulation is regulated, at least in part, by glycan-lectin mediated mechanisms. There is clear evidence that refrigerated platelets are cleared by glycan-lectin mediated clearance mechanisms. Acute platelet cooling clusters glycoprotein (GP) Ibα receptors bearing uncovered N-acetylglucosamine (GlcNAc), and αMβ2 integrins on hepatic macrophages recognise clustered GlcNAc to rapidly clear these platelets from circulation. With prolonged refrigeration GPIbα clustering bearing uncovered galactose increases, which mediates the removal of long-term refrigerated platelets via hepatic Ashwell-Morell receptors (AMR), originally named as asialoglycoprotein receptors. In contrast, little is known about the molecular mechanisms of transfused room temperature platelet clearance. This review examines the role of glycan-lectin mediated clearance of exogenous, i.e. transfused chilled platelet clearance and briefly addresses the current knowledge of stored platelet function, degradation and its relation to platelet clearance. PMID:21781240

Oral sugar clearance and root caries prevalence in rheumatic patients with dry mouth symptoms.

PubMed

Risheim, H; Arneberg, P; Birkhed, D

1992-01-01

The relationship between root caries, oral sugar clearance, salivary flow rate, and salivary counts of mutans streptococci, lactobacilli and candida has been studied in a group of 22 rheumatic patients (age range 40-72 years). The study group comprised all subjects volunteering for a clinical trial on relief of dry mouth symptoms. The median salivary flow was 0.09 ml/min at rest and 0.9 ml/min during chewing stimulation. The median sugar clearance time was about 5 min in the sublingual area and 16 min in the lower buccal vestibule. For subjects with 0-2 root caries lesions the clearance time at both sites was shorter than for subjects with 3 or more lesions (p < 0.05). A long oral clearance time was significantly correlated with age, root caries (DS and DFS), low resting salivary flow, and high salivary counts of mutans streptococci. It is concluded that root caries in rheumatic patients with low salivary flow is significantly related to oral sugar clearance time.

Schwann cells use TAM receptor-mediated phagocytosis in addition to autophagy to clear myelin in a mouse model of nerve injury.

PubMed

Brosius Lutz, Amanda; Chung, Won-Suk; Sloan, Steven A; Carson, Glenn A; Zhou, Lu; Lovelett, Emilie; Posada, Sean; Zuchero, J Bradley; Barres, Ben A

2017-09-19

Ineffective myelin debris clearance is a major factor contributing to the poor regenerative ability of the central nervous system. In stark contrast, rapid clearance of myelin debris from the injured peripheral nervous system (PNS) is one of the keys to this system's remarkable regenerative capacity, but the molecular mechanisms driving PNS myelin clearance are incompletely understood. We set out to discover new pathways of PNS myelin clearance to identify novel strategies for activating myelin clearance in the injured central nervous system, where myelin debris is not cleared efficiently. Here we show that Schwann cells, the myelinating glia of the PNS, collaborate with hematogenous macrophages to clear myelin debris using TAM (Tyro3, Axl, Mer) receptor-mediated phagocytosis as well as autophagy. In a mouse model of PNS nerve crush injury, Schwann cells up-regulate TAM phagocytic receptors Axl and Mertk following PNS injury, and Schwann cells lacking both of these phagocytic receptors exhibit significantly impaired myelin phagocytosis both in vitro and in vivo. Autophagy-deficient Schwann cells also display reductions in myelin clearance after mouse nerve crush injury, as has been recently shown following nerve transection. These findings add a mechanism, Axl/Mertk-mediated myelin clearance, to the repertoire of cellular machinery used to clear myelin in the injured PNS. Given recent evidence that astrocytes express Axl and Mertk and have previously unrecognized phagocytic potential, this pathway may be a promising avenue for activating myelin clearance after CNS injury.

76 FR 35069 - Agency Information Collection Activities; Proposed Collection; Comment Request; Generic Clearance...

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2011-03-11

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2011-04-13

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76 FR 24920 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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76 FR 40981 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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77 FR 52708 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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2012-08-30

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32 CFR 644.521 - Limitations on clearance cost.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Limitations on clearance cost. 644.521 Section 644.521 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) REAL PROPERTY REAL ESTATE HANDBOOK Disposal Clearance of Explosive Hazards and Other Contamination from Proposed...

32 CFR 644.522 - Clearance of military scrap.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Clearance of military scrap. 644.522 Section 644.522 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) REAL PROPERTY REAL ESTATE HANDBOOK Disposal Clearance of Explosive Hazards and Other Contamination from Proposed...

48 CFR 832.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Contract finance office clearance. 832.502-2 Section 832.502-2 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... finance office clearance. Contracting officers must obtain approval from the DSPE before taking the...

48 CFR 32.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Contract finance office clearance. 32.502-2 Section 32.502-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... finance office clearance. The contracting officer shall obtain the approval of the contract finance office...

48 CFR 32.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Contract finance office clearance. 32.502-2 Section 32.502-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... finance office clearance. The contracting officer shall obtain the approval of the contract finance office...

48 CFR 832.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Contract finance office clearance. 832.502-2 Section 832.502-2 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... finance office clearance. Contracting officers must obtain approval from the DSPE before taking the...

48 CFR 32.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contract finance office clearance. 32.502-2 Section 32.502-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... finance office clearance. The contracting officer shall obtain the approval of the contract finance office...

48 CFR 832.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contract finance office clearance. 832.502-2 Section 832.502-2 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... finance office clearance. Contracting officers must obtain approval from the DSPE before taking the...

48 CFR 832.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contract finance office clearance. 832.502-2 Section 832.502-2 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... finance office clearance. Contracting officers must obtain approval from the DSPE before taking the...

48 CFR 32.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Contract finance office clearance. 32.502-2 Section 32.502-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... finance office clearance. The contracting officer shall obtain the approval of the contract finance office...

10 CFR 10.21 - Suspension of access authorization and/or employment clearance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... ELIGIBILITY FOR ACCESS TO RESTRICTED DATA OR NATIONAL SECURITY INFORMATION OR AN EMPLOYMENT CLEARANCE... access authorization and/or an employment clearance, the Director, Division of Facilities and Security... Corporate Management and Chief Information Officer or other Deputy Executive Director, his or her...

10 CFR 10.21 - Suspension of access authorization and/or employment clearance.

Code of Federal Regulations, 2013 CFR

2013-01-01

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77 FR 32144 - Agency Information Collection Activities: Comment Request; Generic Survey Clearance for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-31

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49 CFR 230.110 - Pilots.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Pilots. 230.110 Section 230.110 Transportation... and Equalizing System § 230.110 Pilots. (a) General provisions. Pilots shall be securely attached... clearance. The minimum clearance of pilot above the rail shall be 3 inches and the maximum clearance shall...

75 FR 38775 - Proposed Information Collection; Comment Request; Generic Clearance for Customer Satisfaction...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

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33 CFR 207.185 - Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation. 207.185 Section 207.185 Navigation and... § 207.185 Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation...

33 CFR 207.185 - Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation. 207.185 Section 207.185 Navigation and... § 207.185 Taylors Bayou, Tex., Beaumont Navigation District Lock; use, administration, and navigation...

19 CFR 4.61 - Requirements for clearance.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Requirements for clearance. 4.61 Section 4.61 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE... made by filing Customs Form 1300 (Vessel Entrance or Clearance Statement) executed by the vessel master...

19 CFR 4.61 - Requirements for clearance.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Requirements for clearance. 4.61 Section 4.61 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE... made by filing Customs Form 1300 (Vessel Entrance or Clearance Statement) executed by the vessel master...

19 CFR 4.61 - Requirements for clearance.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Requirements for clearance. 4.61 Section 4.61 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE... made by filing Customs Form 1300 (Vessel Entrance or Clearance Statement) executed by the vessel master...

19 CFR 4.61 - Requirements for clearance.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Requirements for clearance. 4.61 Section 4.61 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE... made by filing Customs Form 1300 (Vessel Entrance or Clearance Statement) executed by the vessel master...

30 CFR 56.11005 - Fixed ladder anchorage and toe clearance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Fixed ladder anchorage and toe clearance. 56.11005 Section 56.11005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Travelways § 56.11005 Fixed ladder anchorage and toe clearance. Fixed ladders shall be anchored securely and...

30 CFR 56.11005 - Fixed ladder anchorage and toe clearance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fixed ladder anchorage and toe clearance. 56.11005 Section 56.11005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Travelways § 56.11005 Fixed ladder anchorage and toe clearance. Fixed ladders shall be anchored securely and...

30 CFR 56.11005 - Fixed ladder anchorage and toe clearance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Fixed ladder anchorage and toe clearance. 56.11005 Section 56.11005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Travelways § 56.11005 Fixed ladder anchorage and toe clearance. Fixed ladders shall be anchored securely and...

30 CFR 56.11005 - Fixed ladder anchorage and toe clearance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Fixed ladder anchorage and toe clearance. 56.11005 Section 56.11005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Travelways § 56.11005 Fixed ladder anchorage and toe clearance. Fixed ladders shall be anchored securely and...

30 CFR 56.11005 - Fixed ladder anchorage and toe clearance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Fixed ladder anchorage and toe clearance. 56.11005 Section 56.11005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Travelways § 56.11005 Fixed ladder anchorage and toe clearance. Fixed ladders shall be anchored securely and...

76 FR 22937 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-25

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76 FR 25693 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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2011-05-05

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76 FR 37825 - Agency Information Collection Activities; Generic Clearance for the Collection of Qualitative...

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2011-06-28

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76 FR 13020 - Agency Information Collection Activities: Comment Request; Generic Clearance for the Collection...

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2011-03-09

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76 FR 14948 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-18

...; Comment Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery... Qualitative Feedback on Agency Service Delivery'' to OMB for approval under the Paperwork Reduction Act (PRA... the CPSC Docket No. CPSC [ ] and the title ``Generic Clearance for the Collection of Qualitative...

78 FR 26087 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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2013-05-03

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76 FR 15027 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

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2011-03-18

... clustering), the precision requirements or power calculations that justify the proposed sample size, the...; Comment Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery... Clearance for the Collection of Qualitative Feedback on Agency Service Delivery'' to OMB for approval under...

76 FR 19826 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-08

... calculations that justify the proposed sample size, the expected response rate, methods for assessing potential... Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery AGENCY... (Generic ICR): ``Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery...

75 FR 80542 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-22

... calculations that justify the proposed sample size, the expected response rate, methods for assessing potential...; Comment Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery... Collection Request (Generic ICR): ``Generic Clearance for the Collection of Qualitative Feedback on Agency...

76 FR 13019 - Agency Information Collection Activities: Comment Request; Generic Clearance for the Collection...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-09

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76 FR 20967 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

... requirements or power calculations that justify the proposed sample size, the expected response rate, methods... Request; Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery AGENCY: U... Clearance for the Collection of Qualitative Feedback on Agency Service Delivery'' to OMB for approval under...

76 FR 70460 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-14

... of Qualitative Feedback on Agency Service Delivery ACTION: 30-Day notice of submission of information... Request (Generic ICR): ``Generic Clearance for the Collection of Qualitative Feedback on Agency Service... INFORMATION: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery...

77 FR 2659 - Airworthiness Directives; Cessna Aircraft Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-19

...), and of the bearing cup for corrosion, turned cup, or clearance that exceeds limits, and repair as... cup for corrosion, turned cup, or clearance that exceeds limits, and repair if necessary; measuring... on the metal), and of the bearing cup for corrosion, turned cup, or clearance that exceeds limits...

32 CFR 644.517 - Clearance of Army lands.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Clearance of Army lands. 644.517 Section 644.517 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) REAL PROPERTY REAL ESTATE HANDBOOK Disposal Clearance of Explosive Hazards and Other Contamination from Proposed Excess Land...

48 CFR 1432.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Contract finance office clearance. 1432.502-2 Section 1432.502-2 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... finance office clearance. The CO shall obtain approval of the bureau finance office prior to taking...

48 CFR 1432.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Contract finance office clearance. 1432.502-2 Section 1432.502-2 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... finance office clearance. The CO shall obtain approval of the bureau finance office prior to taking...

48 CFR 1432.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Contract finance office clearance. 1432.502-2 Section 1432.502-2 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... finance office clearance. The CO shall obtain approval of the bureau finance office prior to taking...

48 CFR 1432.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Contract finance office clearance. 1432.502-2 Section 1432.502-2 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR... finance office clearance. The CO shall obtain approval of the bureau finance office prior to taking...

78 FR 22020 - Agency Information Collection Activities: Requests for Comments; Clearance of New Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-12

... Control Number: 2120-XXXX. Title: Safety Awareness, Feedback, and Evaluation (SAFE) Program. Form Numbers: No FAA forms are associated with this collection. Type of Review: Clearance of a new information... Activities: Requests for Comments; Clearance of New Approval of Information Collection: Safety Awareness...

Benefits of Improved HP Turbine Active Clearance Control

NASA Technical Reports Server (NTRS)

Ruiz, Rafael; Albers, Bob; Sak, Wojciech; Seitzer, Ken; Steinetz, Bruce M.

2007-01-01

As part of the NASA Propulsion 21 program, GE Aircraft Engines was contracted to develop an improved high pressure turbine(HPT) active clearance control (ACC) system. The system is envisioned to minimize blade tip clearances to improve HPT efficiency throughout the engine operation range simultaneously reducing fuel consumption and emissions.

49 CFR 392.12 - Highway-rail crossings; safe clearance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Highway-rail crossings; safe clearance. 392.12... DRIVING OF COMMERCIAL MOTOR VEHICLES Driving of Commercial Motor Vehicles § 392.12 Highway-rail crossings; safe clearance. No driver of a commercial motor vehicle shall drive onto a highway-rail grade crossing...

49 CFR 392.12 - Highway-rail crossings; safe clearance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Highway-rail crossings; safe clearance. 392.12... DRIVING OF COMMERCIAL MOTOR VEHICLES Driving of Commercial Motor Vehicles § 392.12 Highway-rail crossings; safe clearance. No driver of a commercial motor vehicle shall drive onto a highway-rail grade crossing...

5 CFR 1320.11 - Clearance of collections of information in proposed rules.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Clearance of collections of information in proposed rules. 1320.11 Section 1320.11 Administrative Personnel OFFICE OF MANAGEMENT AND BUDGET OMB DIRECTIVES CONTROLLING PAPERWORK BURDENS ON THE PUBLIC § 1320.11 Clearance of collections of...

5 CFR 1320.12 - Clearance of collections of information in current rules.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Clearance of collections of information in current rules. 1320.12 Section 1320.12 Administrative Personnel OFFICE OF MANAGEMENT AND BUDGET OMB DIRECTIVES CONTROLLING PAPERWORK BURDENS ON THE PUBLIC § 1320.12 Clearance of collections of...

77 FR 56866 - Agency Information Collection Activities: Proposed Collection; Comment Request, Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-14

... Collection Activities: Proposed Collection; Comment Request, Generic Clearance for Cognitive, Pilot and Field... information collection clearance that will allow BJS to conduct a variety of cognitive, pilot, and field test... new or modified data collection, BJS will engage in cognitive, pilot and field test activities to...

77 FR 69658 - Agency Information Collection Activities; Proposed Collection; Comment Request: Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-20

... Activities; Proposed Collection; Comment Request: Generic Clearance for Cognitive, Pilot and Field Studies...) Title of the Form/Collection: BJS Generic Clearance for Cognitive, Pilot, and Field Test Studies. (3... respondents will be involved in exploratory, field test, pilot, cognitive, and focus group work conducted...

77 FR 56867 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-14

... Collection Activities: Proposed Collection; Comment Request; Generic Clearance for Cognitive, Pilot and Field... information collection clearance that will allow BJS to conduct a variety of cognitive, pilot, and field test... new or modified data collection, BJS will engage in cognitive, pilot and field test activities to...

48 CFR 832.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract finance office clearance. 832.502-2 Section 832.502-2 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Progress Payments Based on Costs 832.502-2 Contract finance office clearance. Contracting...

48 CFR 32.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract finance office clearance. 32.502-2 Section 32.502-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Progress Payments Based on Costs 32.502-2 Contract finance office clearance. The contracting...

76 FR 49838 - Proposed Collection; Comment Request for Generic Clearance for the Collection of Qualitative...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-11

... Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery AGENCY: Internal... of Qualitative Feedback on Agency Service Delivery. DATES: Written comments should be received on or... . SUPPLEMENTARY INFORMATION: Title: Generic Clearance for the Collection of Qualitative Feedback on Agency Service...

78 FR 69643 - Proposed Information Collection; Comment Request; Generic Clearance for Customer Satisfaction...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-20

... Clearance for Customer Satisfaction Research AGENCY: U.S. Census Bureau, Commerce. ACTION: Notice. SUMMARY... requesting an extension of the generic clearance to conduct customer satisfaction research which may be in... feedback from its various customer satisfaction research efforts. Each research design is reviewed for...

76 FR 77244 - Renewal of Information Collection; OMB Control Number 1040-0001, DOI Programmatic Clearance for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-12

... Number 1040-0001, DOI Programmatic Clearance for Customer Satisfaction Surveys AGENCY: Department of [email protected] . Reference ``DOI Programmatic Clearance for Customer Satisfaction Surveys'' in your email... public accountability by promoting a new focus on results, service quality, and customer satisfaction...

14 CFR 135.361 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... distance from the point at which the obstruction clearance plane associated with the approach end of the... subpart, obstruction clearance plane means a plane sloping upward from the runway at a slope of 1:20 to... coincides with the centerline of the runway, beginning at the point where the obstruction clearance plane...

14 CFR 121.171 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-01-01

... point at which the obstruction clearance plane associated with the approach end of the runway intersects... clearance plane means a plane sloping upward from the runway at a slope of 1:20 to the horizontal, and... centerline of the runway, beginning at the point where the obstruction clearance plane intersects the...

Experimental Study of Unshrouded Impeller Pump Stage Sensitivity to Tip Clearance

NASA Technical Reports Server (NTRS)

Williams, Robert W.; Zoladz, Thomas; Storey, Anne K.; Skelley, Stephen E.

2002-01-01

This viewgraph presentation provides information on an experiment. Its objective is to experimentally determine unshrouded impeller performance sensitivity to tip clearance. The experiment included: Determining impeller efficiency at scaled operating conditions in water at MSFC's Pump Test Equipment (PTE) Facility; Testing unshrouded impeller at three different tip clearances; Testing each tip clearance configuration at on- and off-design conditions, and collecting unsteady- and steady-state data in each configuration; Determining impeller efficiency directly using drive line torquemeter and pump inlet and exit total pressure measurements.

Simple geometric algorithms to aid in clearance management for robotic mechanisms

NASA Technical Reports Server (NTRS)

Copeland, E. L.; Ray, L. D.; Peticolas, J. D.

1981-01-01

Global geometric shapes such as lines, planes, circles, spheres, cylinders, and the associated computational algorithms which provide relatively inexpensive estimates of minimum spatial clearance for safe operations were selected. The Space Shuttle, remote manipulator system, and the Power Extension Package are used as an example. Robotic mechanisms operate in quarters limited by external structures and the problem of clearance is often of considerable interest. Safe clearance management is simple and suited to real time calculation, whereas contact prediction requires more precision, sophistication, and computational overhead.

Does sleep disturbance affect the amyloid clearance mechanisms in Alzheimer's disease?

PubMed

Yulug, Burak; Hanoglu, Lutfu; Kilic, Ertugrul

2017-10-01

Sleep is an important factor that plays a key role in Alzheimer's disease pathogenesis. However, it is still unclear whether poor-quality sleep may overlap with sleep disturbances in the underlying dysfunctional mechanisms of amyloid beta (Aβ) clearance metabolism. Here, we aimed to evaluate the current evidence on the role of sleep deprivation in Aβ clearance metabolism. To that end, we discuss possible mechanisms underlying the bidirectional interaction between the sleep deprivation and Aβ clearance pathways. © 2017 The Authors. Psychiatry and Clinical Neurosciences © 2017 Japanese Society of Psychiatry and Neurology.

Proficiency testing criteria for clearance level in solid waste gamma measurement in Taiwan.

PubMed

Chen, Chun-Liang; Wang, Jeng-Jong; Chiu, Huang-Sheng

2013-11-01

To guarantee the measurement quality for clearance level in solid waste material, the Institute of Nuclear Energy Research (INER) established the criteria for proficiency testing of clearance level measurement. INER and the Taiwan Accreditation Foundation (TAF) organized the Technique Committee Meeting twice to discuss these criteria in 2011. The participating laboratories must completely conform to the ISO/IEC 17025, and they also must meet the requirements of the criteria. According to the criteria, the participating laboratories analyzed the minimum detectable amount (MDA) and that should be less than 20% of the clearance level (AMDA) given in the Atomic Energy Council's (AEC) "Regulations on Clearance Level for Radioactive Waste Management". The testing results should conform to the deviation and traceability requirements. Copyright © 2013 Elsevier Ltd. All rights reserved.

JT9D-70/59 Improved High Pressure Turbine Active Clearance Control System. [for specific fuel consumption improvement

NASA Technical Reports Server (NTRS)

Gaffin, W. O.

1979-01-01

The JT9D-70/59 high pressure turbine active clearance control system was modified to provide reduction of blade tip clearance when the system is activated during cruise operation. The modification increased the flow capacity and air impingement effectiveness of the cooling air manifold to augment turbine case shrinkage capability, and increased responsiveness of the airseal clearance to case shrinkage. The simulated altitude engine testing indicated a significant improvement in specific fuel consumption with the modified system. A 1000 cycle engine endurance test showed no unusual wear or performance deterioration effects on the engine or the clearance control system. Rig tests indicated that the air impingement and seal support configurations used in the engine tests are near optimum.

Output Error Analysis of Planar 2-DOF Five-bar Mechanism

NASA Astrophysics Data System (ADS)

Niu, Kejia; Wang, Jun; Ting, Kwun-Lon; Tao, Fen; Cheng, Qunchao; Wang, Quan; Zhang, Kaiyang

2018-03-01

Aiming at the mechanism error caused by clearance of planar 2-DOF Five-bar motion pair, the method of equivalent joint clearance of kinematic pair to virtual link is applied. The structural error model of revolute joint clearance is established based on the N-bar rotation laws and the concept of joint rotation space, The influence of the clearance of the moving pair is studied on the output error of the mechanis. and the calculation method and basis of the maximum error are given. The error rotation space of the mechanism under the influence of joint clearance is obtained. The results show that this method can accurately calculate the joint space error rotation space, which provides a new way to analyze the planar parallel mechanism error caused by joint space.

Application of an in vitro OAT assay in drug design and optimization of renal clearance.

PubMed

Soars, Matthew G; Barton, Patrick; Elkin, Lisa L; Mosure, Kathleen W; Sproston, Joanne L; Riley, Robert J

2014-07-01

1. Optimization of renal clearance is a complex balance between passive and active processes mediated by renal transporters. This work aimed to characterize the interaction of a series of compounds with rat and human organic anion transporters (OATs) and develop quantitative structure-activity relationships (QSARs) to optimize renal clearance. 2. In vitro inhibition assays were established for human OAT1 and rat Oat3 and rat in vivo renal clearance was obtained. Statistically significant quantitative relationships were explored between the compounds' physical properties, their affinity for OAT1 and oat3 and the inter-relationship with unbound renal clearance (URC) in rat. 3. Many of the compounds were actively secreted and in vitro analysis demonstrated that these were ligands for rat and human OAT transporters (IC50 values ranging from <1 to >100 µM). Application of resultant QSAR models reduced renal clearance in the rat from 24 to <0.1 ml/min/kg. Data analysis indicated that the properties associated with increasing affinity at OATs are the same as those associated with reducing URC but orthogonal in nature. 4. This study has demonstrated that OAT inhibition data and QSAR models can be successfully used to optimize rat renal clearance in vivo and provide confidence of translation to humans.

ADAPTIVE CLEARANCE CONTROL SYSTEMS FOR TURBINE ENGINES

NASA Technical Reports Server (NTRS)

Blackwell, Keith M.

2004-01-01

The Controls and Dynamics Technology Branch at NASA Glenn Research Center primarily deals in developing controls, dynamic models, and health management technologies for air and space propulsion systems. During the summer of 2004 I was granted the privilege of working alongside professionals who were developing an active clearance control system for commercial jet engines. Clearance, the gap between the turbine blade tip and the encompassing shroud, increases as a result of wear mechanisms and rubbing of the turbine blades on shroud. Increases in clearance cause larger specific fuel consumption (SFC) and loss of efficient air flow. This occurs because, as clearances increase, the engine must run hotter and bum more fuel to achieve the same thrust. In order to maintain efficiency, reduce fuel bum, and reduce exhaust gas temperature (EGT), the clearance must be accurately controlled to gap sizes no greater than a few hundredths of an inch. To address this problem, NASA Glenn researchers have developed a basic control system with actuators and sensors on each section of the shroud. Instead of having a large uniform metal casing, there would be sections of the shroud with individual sensors attached internally that would move slightly to reform and maintain clearance. The proposed method would ultimately save the airline industry millions of dollars.

Use of specific radioimmunoassays to determine the renal clearance rates of estrone and 17. beta. -estradiol during the menstrual cycle. [Tritium tracer techniques

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

Wright, K.; Collins, D.C.; Preedy, J.R.K.

Specific RIAs requiring ether extraction only were established for estrone and 17..beta..-estradiol both in plasma and in urine from the nonpregnant female. These assays were used to measure the renal clearance rates of estrone and of 17..beta..-estradiol in eight ambulatory women in the follicular and in the luteal phases of the menstrual cycle. The mean (+-SE) for the renal clearance rate of estrone was 0.71 +- 0.058 ml/min in the follicular phase and 1.26 +- 0.35 ml/min in the luteal phase. The mean (+-SE) renal clearance rate of 17..beta..-estradiol was 0.44 +- 0.055 ml/min in the follicular phase and 0.29more » +- 0.043 ml/min in the luteal phase. There was no significant difference in the renal clearance rates of either estrone or of 17..beta..-estradiol between the follicular and luteal phases of the cycle. The renal clearances of estrone and 17..beta..-estradiol were highly correlated (r = 0.84; P < 0.01). The renal clearance rate of estrone was significantly greater than that of 17..beta..-estradiol in both phases of the cycle (P < 0.01).« less

33 CFR 164.11 - Navigation under way: General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Navigation under way: General. 164.11 Section 164.11 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.11 Navigation under way: General...

33 CFR 164.11 - Navigation under way: General.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Navigation under way: General. 164.11 Section 164.11 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.11 Navigation under way: General...

33 CFR 164.11 - Navigation under way: General.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Navigation under way: General. 164.11 Section 164.11 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.11 Navigation under way: General...

The tribological behaviour of different clearance MOM hip joints with lubricants of physiological viscosities.

PubMed

Hu, X Q; Wood, R J K; Taylor, A; Tuke, M A

2011-11-01

Clearance is one of the most influential parameters on the tribological performance of metal-on-metal (MOM) hip joints and its selection is a subject of considerable debate. The objective of this paper is to study the lubrication behaviour of different clearances for MOM hip joints within the range of human physiological and pathological fluid viscosities. The frictional torques developed by MOM hip joints with a 50 mm diameter were measured for both virgin surfaces and during a wear simulator test. Joints were manufactured with three different diametral clearances: 20, 100, and 200 microm. The fluid used for the friction measurements which contained different ratios of 25 percent newborn calf serum and carboxymethyl cellulose (CMC) with the obtained viscosities values ranging from 0.001 to 0.71 Pa s. The obtained results indicate that the frictional torque for the 20 microm clearance joint remains high over the whole range of the viscosity values. The frictional torque of the 100 microm clearance joint was low for the very low viscosity (0.001 Pa s) lubricant, but increased with increasing viscosity value. The frictional torque of the 200 microm clearance joint was high at very low viscosity levels, however, it reduced with increasing viscosity. It is concluded that a smaller clearance level can enhance the formation of an elastohydrodynamic lubrication (EHL) film, but this is at the cost of preventing fluid recovery between the bearing surfaces during the unloaded phase of walking. Larger clearance bearings allow a better recovery of lubricant during the unloaded phase, which is necessary for higher viscosity lubricants. The selection of the clearance value should therefore consider both the formation of the EHL film and the fluid recovery as a function of the physiological viscosity in order to get an optimal tribological performance for MOM hip joints. The application of either 25 per cent bovine serum or water in existing in vitro tribological study should also be revised to consider the relevance of clinic synovial fluid viscosities and to avoid possible misleading results.

Transitional probability-based model for HPV clearance in HIV-1-positive adolescent females.

PubMed

Kravchenko, Julia; Akushevich, Igor; Sudenga, Staci L; Wilson, Craig M; Levitan, Emily B; Shrestha, Sadeep

2012-01-01

HIV-1-positive patients clear the human papillomavirus (HPV) infection less frequently than HIV-1-negative. Datasets for estimating HPV clearance probability often have irregular measurements of HPV status and risk factors. A new transitional probability-based model for estimation of probability of HPV clearance was developed to fully incorporate information on HIV-1-related clinical data, such as CD4 counts, HIV-1 viral load (VL), highly active antiretroviral therapy (HAART), and risk factors (measured quarterly), and HPV infection status (measured at 6-month intervals). Data from 266 HIV-1-positive and 134 at-risk HIV-1-negative adolescent females from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort were used in this study. First, the associations were evaluated using the Cox proportional hazard model, and the variables that demonstrated significant effects on HPV clearance were included in transitional probability models. The new model established the efficacy of CD4 cell counts as a main clearance predictor for all type-specific HPV phylogenetic groups. The 3-month probability of HPV clearance in HIV-1-infected patients significantly increased with increasing CD4 counts for HPV16/16-like (p<0.001), HPV18/18-like (p<0.001), HPV56/56-like (p = 0.05), and low-risk HPV (p<0.001) phylogenetic groups, with the lowest probability found for HPV16/16-like infections (21.60±1.81% at CD4 level 200 cells/mm(3), p<0.05; and 28.03±1.47% at CD4 level 500 cells/mm(3)). HIV-1 VL was a significant predictor for clearance of low-risk HPV infections (p<0.05). HAART (with protease inhibitor) was significant predictor of probability of HPV16 clearance (p<0.05). HPV16/16-like and HPV18/18-like groups showed heterogeneity (p<0.05) in terms of how CD4 counts, HIV VL, and HAART affected probability of clearance of each HPV infection. This new model predicts the 3-month probability of HPV infection clearance based on CD4 cell counts and other HIV-1-related clinical measurements.

Alcohol consumption decreases lactate clearance in acutely injured patients☆

PubMed Central

Dezman, Zachary D.W.; Comer, Angela C.; Narayan, Mayur; Scalea, Thomas M.; Hirshon, Jon Mark; Smith, Gordon S.

2017-01-01

Introduction Alcohol, a common risk factor for injury, has direct toxic effects on the liver. The use of lactate clearance has been well described as an indicator of the adequacy of resuscitation in injured patients. We investigated whether acutely injured patients with positive blood alcohol content (+BAC) had less lactate clearance than sober patients. Methods We conducted a retrospective cohort study of acutely injured patients treated at an urban Level 1 trauma centre between January 2010 and December 2012. Blood alcohol and venous lactate levels were measured on all patients at the time of arrival. Study subjects were patients transported directly from the scene of injury, who had an elevated lactate concentration on arrival (≥3.0 mmol/L) and at least one subsequent lactate measurement within 24 h after admission. Lactate clearance ([Lactate1 − Lactate2]/Lactate1) was calculated for all patients. Chi-squared tests were used to compare values from sober and intoxicated subjects. Lactate clearance was plotted against alcohol levels and stratified by age and Injury Severity Score (ISS). Results Serial lactate concentration measurements were obtained in 3910 patients; 1674 of them had +BAC. Patients with +BAC were younger (mean age: 36.6 [SD 14.7] vs 41.0 [SD 19.9] years [p = 0.0001]), were more often male (83.4% vs 75.9% [p = 0.0001]), had more minor injuries (ISS < 9) (33.8% vs 27.1% [p = 0.0001]), had a lower in-hospital mortality rate (1.4% vs 3.9% [p = 0.0001]), but also had lower average lactate clearance (37.8% vs 47.6% [p = 0.0001]). The lactate clearance of the sober patients (47.6 [SD 33.5]) was twice that of those with +BAC >400 (23.5 [SD 6.5]). Lactate clearance decreased with increasing BAC irrespective of age and ISS. Conclusions In a large group of acutely injured patients, a dose-dependent decrease in lactate clearance was seen in those with elevated BAC. This relationship will cause a falsely elevated lactate reading or prolong lactate clearance and should be taken into account when evaluating patients with +BAC. PMID:27025567

High-dose methotrexate therapy of childhood acute lymphoblastic leukemia: lack of relation between serum methotrexate concentration and creatinine clearance.

PubMed

Joannon, Pilar; Oviedo, Iris; Campbell, Myriam; Tordecilla, Juan

2004-07-01

The objectives of this study were: (1) to analyze the relation of serum methotrexate (MTX) concentration with creatinine clearance, (2) to compare the leucovorin rescue dose administered to the patients based on creatinine clearance, with the one calculated according to serum MTX levels, and (3) to determine MTX-related toxicity. Thirty children with high-risk non-B acute lymphoblastic leukemia (ALL) treated according to the national protocol (PINDA 92) based on ALL BFM 90, were randomized to receive consolidation with four doses of either 1 or 2 g/m(2) MTX as a 24-hr infusion, at 2-week intervals (group M1 and M2, respectively). Serum MTX concentrations were measured at 24, 42, and 48 hr after beginning the infusion and were analyzed retrospectively. The creatinine clearance was calculated after 12-hr intravenous hydration prior to each MTX dose. Leucovorin dosage was adjusted according to creatinine clearance. Serum MTX concentrations at 24, 42, and 48 hr after starting the infusion were not related to creatinine clearance in both treatment groups. Leucovorin rescue administered according to creatinine clearance was excessive in 43% in group M1 and in 51% in group M2, as compared to the dose calculated according to serum MTX levels. No serious clinical complications were observed. These results suggest that creatinine clearance is not a good parameter to calculate leucovorin rescue. MTX-related toxicity in this group of patients receiving a dose of 1 or 2 g/m(2) and rescued with leucovorin without monitoring serum MTX levels was acceptable. Copyright 2004 Wiley-Liss, Inc.

Interferon lambda 4 (IFNL4) gene polymorphism is associated with spontaneous clearance of HCV in HIV-1 positive patients.

PubMed

Alves, Camila Fernanda da Silveira; Grott, Camila Schultz; Lunge, Vagner Ricardo; Béria, Jorge Umberto; Tietzmann, Daniela Cardoso; Stein, Airton Tetelbom; Simon, Daniel

2016-01-01

Approximately one-third of the individuals infected with human immunodeficiency virus type 1 (HIV-1) are co-infected with hepatitis C virus (HCV). Co-infected patients have an increased risk for developing end-stage liver diseases. Variants upstream of the IFNL3 gene have been associated with spontaneous and treatment-induced clearance of HCV infection. Recently, a novel polymorphism was discovered, denoted IFNL4 ΔG > TT (rs368234815), which seems to be a better predictor of spontaneous clearance than the IFNL4 rs12979860 polymorphism. We aimed to determine the prevalence of the IFNL4 ΔG > TT variants and to evaluate the association with spontaneous clearance of HCV infection in Brazilian HIV-1 patients. The IFNL4 ΔG > TT genotypes were analyzed by polymerase chain reaction followed by restriction digestion in 138 HIV-1 positive patients who had an anti-HCV positive result. Spontaneous clearance of HCV was observed in 34 individuals (24.6%). IFNL4 genotype distribution was significantly different between individuals who had spontaneous clearance and chronic HCV patients (p=0.002). The probability of spontaneous clearance of HCV infection for patients with the IFNL4 TT/TT genotype was 3.6 times higher than for patients carrying the IFNL4 ΔG allele (OR=3.63, 95% CI:1.51-8.89, p=0.001). The IFNL4 ΔG > TT polymorphism seems to be better than IFNL4 rs12979860 to predict spontaneous clearance of the HCV in Brazilian HIV-1 positive patients.

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

Lee, H.B.; Blaufox, M.D.

Rats with one kidney clamped (2K1C), both kidneys clamped (2K2C), unilaterally nephrectomized with remaining kidney clamped (1K1C), and normals, were studied using /sup 99m/Tc mercaptoacetyltriglycine ((/sup 99m/Tc)MAG-3) and /sup 131/I orthoiodohippurate ((/sup 131/I)OIH). Clearances of (/sup 99m/Tc)MAG-3 and (/sup 131/I)OIH were performed after constricted rats became hypertensive. Clearances were repeated after i.v. Captopril. Clearances of (/sup 99m/Tc)MAG-3 and (/sup 131/I)OIH in normals didn't change significantly after Captopril. Clearances of (/sup 99m/Tc)MAG-3 and (/sup 131/I)OIH decreased insignificantly after Captopril in the 2K2C model. in the 2K1C group, normal kidney clearance increased ((/sup 99m/Tc)MAG-3 p less than 0.01 and (/sup 131/I)OIH pmore » less than 0.025) and clamped kidney clearance decreased after inhibition ((/sup 99m/Tc)MAG-3, p less than 0.01, (/sup 131/I)OIH p less than 0.02). Clearances increased in the 1K1C group after Captopril ((/sup 99m/Tc)MAG-3 p less than 0.0025 and (/sup 131/I)OIH, p less than 0.001). The ratio of (/sup 99m/Tc)MAG-3 to (/sup 131/I)OIH before Captopril was 0.81 and 0.84 after Captopril. Changes in renal function after Captopril depend on the model of renovascular hypertension and possibly the dose administered. Technetium-99m MAG-3 clearance parallels (/sup 131/I)orthoiodohippurate in renovascular hypertension.« less

Semi-mechanistic autoinduction model of midazolam in critically ill patients: population pharmacokinetic analysis.

PubMed

Aoyama, T; Hirata, K; Yamamoto, Y; Yokota, H; Hayashi, H; Aoyama, Y; Matsumoto, Y

2016-08-01

Midazolam (MDZ) is commonly used for sedating critically ill patients. The daily dose required for adequate sedation increases in increments over 100 h after administration. The objectives of this study were to characterize the MDZ pharmacokinetics in critically ill patients and to describe the phenomenon of increasing daily dose by means of population pharmacokinetic analysis. Data were obtained from 30 patients treated in an intensive care unit. The patients received MDZ intravenously as a combination of bolus and continuous infusion. Serum MDZ concentration was assayed by high-performance liquid chromatography. Population pharmacokinetic analysis was performed using the NONMEM software package. The alteration of clearance unexplained by demographic factors and clinical laboratory data was described as an autoinduction of MDZ clearance using a semi-mechanistic pharmacokinetic-enzyme turnover model. The final population pharmacokinetic model was a one-compartment model estimated by incorporating a semi-mechanistic pharmacokinetic-enzyme turnover model for clearance, taking autoinduction into account. A significant covariate for MDZ clearance was total bilirubin. An increase in total bilirubin indicated a reduction in MDZ clearance. From simulation using the population pharmacokinetic parameters obtained in this study, MDZ clearance increased 2·3 times compared with pre-induced clearance 100 h after the start of 12·5 mg/h continuous infusion. Autoinduction and total bilirubin were significant predictors of the clearance of MDZ in this population. Step-by-step dosage adjustment using this population pharmacokinetic model may be useful for establishing a MDZ dosage regimen in critically ill patients. © 2016 John Wiley & Sons Ltd.

Interferon lambda 4 (IFNL4) gene polymorphism is associated with spontaneous clearance of HCV in HIV-1 positive patients

PubMed Central

Alves, Camila Fernanda da Silveira; Grott, Camila Schultz; Lunge, Vagner Ricardo; Béria, Jorge Umberto; Tietzmann, Daniela Cardoso; Stein, Airton Tetelbom; Simon, Daniel

2016-01-01

Abstract Approximately one-third of the individuals infected with human immunodeficiency virus type 1 (HIV-1) are co-infected with hepatitis C virus (HCV). Co-infected patients have an increased risk for developing end-stage liver diseases. Variants upstream of the IFNL3 gene have been associated with spontaneous and treatment-induced clearance of HCV infection. Recently, a novel polymorphism was discovered, denoted IFNL4 ΔG > TT (rs368234815), which seems to be a better predictor of spontaneous clearance than the IFNL4 rs12979860 polymorphism. We aimed to determine the prevalence of the IFNL4 ΔG > TT variants and to evaluate the association with spontaneous clearance of HCV infection in Brazilian HIV-1 patients. The IFNL4 ΔG > TT genotypes were analyzed by polymerase chain reaction followed by restriction digestion in 138 HIV-1 positive patients who had an anti-HCV positive result. Spontaneous clearance of HCV was observed in 34 individuals (24.6%). IFNL4 genotype distribution was significantly different between individuals who had spontaneous clearance and chronic HCV patients (p=0.002). The probability of spontaneous clearance of HCV infection for patients with the IFNL4 TT/TT genotype was 3.6 times higher than for patients carrying the IFNL4 ΔG allele (OR=3.63, 95% CI:1.51-8.89, p=0.001). The IFNL4 ΔG > TT polymorphism seems to be better than IFNL4 rs12979860 to predict spontaneous clearance of the HCV in Brazilian HIV-1 positive patients. PMID:27560987

Population Pharmacokinetics of Ceftizoxime Administered by Continuous Infusion in Clinically Ill Adult Patients

PubMed Central

Facca, Bryan; Frame, Bill; Triesenberg, Steve

1998-01-01

Ceftizoxime is a widely used beta-lactam antimicrobial agent, but pharmacokinetic data for use with clinically ill patients are lacking. We studied the population pharmacokinetics of ceftizoxime in 72 clinically ill patients at a community-based, university-affiliated hospital. A population pharmacokinetic model for ceftizoxime was created by using a prospective observational design. Ceftizoxime was administered by continuous infusion to treat patients with proven or suspected bacterial infections. While the patients were receiving infusions of ceftizoxime, serum samples were collected for pharmacokinetic analysis with the nonlinear mixed-effect modeling program NONMEM. In addition to clearance and volume of distribution, various comorbidities were examined for their influence on the kinetics. All 72 subjects completed the study, and 114 serum samples were collected. Several demographic and comorbidity variables, namely, age, weight, serum creatinine levels, congestive heart failure, and long-term ventilator dependency, had a significant impact on the estimate for ceftizoxime clearance. A mixture model, or two populations for estimation of ceftizoxime clearance, was discovered. One population presented with an additive clearance component of 1.6 liters per h. In addition, a maximizer function for serum creatinine levels was found. In summary, two models for ceftizoxime clearance, mixture and nonmixture, were found and are presented. Clearance for ceftizoxime can be estimated with commonly available clinical information and the models presented. From the clearance estimates, the dose of ceftizoxime to maintain the desired concentration in serum can be determined. Work is needed to validate the model for drug clearance and to evaluate its predictive performance. PMID:9661021

33 CFR 164.78 - Navigation under way: Towing vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under way...

33 CFR 164.78 - Navigation under way: Towing vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under way...

33 CFR 164.78 - Navigation under way: Towing vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under way...

33 CFR 401.54 - Interference with navigation aids.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

33 CFR 401.54 - Interference with navigation aids.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

33 CFR 401.54 - Interference with navigation aids.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

33 CFR 401.54 - Interference with navigation aids.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

78 FR 68861 - Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-15

... Devices, Navigation and Display Systems, Radar Systems, Navigational Aids, Mapping Systems and Related... navigation products, including GPS devices, navigation and display systems, radar systems, navigational aids..., radar systems, navigational aids, mapping systems and related software by reason of infringement of one...

33 CFR 100.45 - Establishment of aids to navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... navigation incidental to the holding of a regatta or marine parade are private aids to navigation as... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Establishment of aids to navigation. 100.45 Section 100.45 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND...

33 CFR 401.54 - Interference with navigation aids.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

An Examination of Selected Datacom Options for the Near-Term Implementation of Trajectory Based Operations

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Lachter, Joel B.; Battiste, Vernol; Lim, Veranika; Brandt, Summer L.; Koteskey, Robert W.; Dao, Arik-Quang V.; Ligda, Sarah V.; Wu, Shu-Chieh

2011-01-01

A primary feature of the Next Generation Air Transportation System (NextGen) is trajectory based operations (TBO). Under TBO, aircraft flight plans are known to computer systems on the ground that aid in scheduling and separation. The Future Air Navigation System (FANS) was developed to support TBO, but relatively few aircraft in the US are FANSequipped. Thus, any near-term implementation must provide TBO procedures for non-FANS aircraft. Previous research has explored controller clearances, but any implementation must also provide procedures for aircraft requests. The work presented here aims to surface issues surrounding TBO communication procedures for non-FANS aircraft and for aircraft requesting deviations around weather. Three types of communication were explored: Voice, FANS, and ACARS,(Aircraft Communications Addressing and Reporting System). ACARS and FANS are datacom systems that differ in that FANS allows uplinked flight plans to be loaded into the Flight Management System (FMS), while ACARS delivers flight plans as text that must be entered manually via the Control Display Unit (CDU). Sixteen pilots (eight two-person flight decks) and four controllers participated in 32 20-minute scenarios that required the flight decks to navigate through convective weather as they approached their top of descents (TODs). Findings: The rate of non-conformance was higher than anticipated, with aircraft off path more than 20% of the time. Controllers did not differentiate between the ACARS and FANS datacom, and were mixed in their preference for Voice vs. datacom (ACARS and FANS). Pilots uniformly preferred Voice to datacom, particularly ACARS. Much of their dislike appears to result from the slow response times in the datacom conditions. As a result, participants frequently resorted to voice communication. These results imply that, before implementing TBO in environments where pilots make weather deviation requests, further research is needed to develop communication procedures that integrate voice and datacom.

20 CFR 653.501 - Requirements for accepting and processing clearance orders.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., DEPARTMENT OF LABOR SERVICES OF THE EMPLOYMENT SERVICE SYSTEM Agricultural Clearance Order Activity § 653.501... function of the job service as a no-fee labor exchange, that is, as a forum for bringing together employers... referred through the clearance system shall be notified to contact a local job service office, preferably...

20 CFR 653.501 - Requirements for accepting and processing clearance orders.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., DEPARTMENT OF LABOR SERVICES OF THE EMPLOYMENT SERVICE SYSTEM Agricultural Clearance Order Activity § 653.501... function of the job service as a no-fee labor exchange, that is, as a forum for bringing together employers... referred through the clearance system shall be notified to contact a local job service office, preferably...

75 FR 75189 - 30-Day Notice of Proposed Information Collection: Form DS-3057, Medical Clearance Update, OMB...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-02

... on whether a federal employee and family members will have sufficient medical resources at a...-3057, Medical Clearance Update, OMB 1405-0131 ACTION: Notice of request for public comments. SUMMARY... Reduction Act of 1995. Title of Information Collection: Medical Clearance Update. OMB Control Number: 1405...

75 FR 62444 - 60-Day Notice of Proposed Information Collection: Form DS-3057, Medical Clearance Update, OMB...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-08

... employee and family members will have sufficient medical resources at a diplomatic mission abroad to...-3057, Medical Clearance Update, OMB 1405-0131 ACTION: Notice of request for public comments. SUMMARY... the Paperwork Reduction Act of 1995. Title of Information Collection: Medical Clearance Update. OMB...

32 CFR 644.516 - Clearance of Air Force lands.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Clearance of Air Force lands. 644.516 Section 644... Excess Land and Improvements § 644.516 Clearance of Air Force lands. The Chief of Engineers has no responsibility for inspecting or clearing excess Air Force land of explosives or chemical/biological contaminants...

Towards improved models for predicting bioconcentration of well-metabolized compounds by rainbow trout using measured rates of in vitro intrinsic clearance

EPA Science Inventory

Consensus models were developed to predict the bioconcentration of well-metabolized chemicals by rainbow trout. The models employ intrinsic clearance data from in vitro studies with liver S9 fractions or isolated hepatocytes to estimate a liver clearance rate which is extrapolat...

Hepatic clearance of 6 polyaromatic aromatic hydrocarbons by isolated trout livers: Prediction from in vitro clearance by liver S9 fractions

EPA Science Inventory

An isolated perfused trout liver preparation was used to evaluate in vitro-to-in vivo metabolism extrapolation procedures for fish. Hepatic clearance (CLH) studies were conducted with six polyaromatic hydrocarbons (PAH) using an experimental design wherein each liver acted as it...

77 FR 47492 - Agency Information Collection Activities: Requests for Comments; Clearance of a New Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

... collection. This is a new generic clearance for the purpose of gathering customer satisfaction data directly from customers for a wide variety of services. DATES: Written comments should be submitted by October 9... Activities: Requests for Comments; Clearance of a New Approval of Information Collection: FAA Customer...

78 FR 5855 - Agency Information Collection Activities: Requests for Comments; Clearance of a New Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-28

... generic clearance for the purpose of gathering customer satisfaction data directly from customers for a... Activities: Requests for Comments; Clearance of a New Approval of Information Collection: FAA Customer... INFORMATION: OMB Control Number: 2120-XXXX Title: FAA Customer Service Surveys Form Numbers: There are no FAA...

49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Open-wire transmission line; clearance to other..., AND APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.73 Open-wire transmission line; clearance to other circuits. Open-wire transmission line operating at voltage of 750 volts or...

49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Open-wire transmission line; clearance to other..., AND APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.73 Open-wire transmission line; clearance to other circuits. Open-wire transmission line operating at voltage of 750 volts or...

14 CFR 103.23 - Flight visibility and cloud clearance requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Flight visibility and cloud clearance... Flight visibility and cloud clearance requirements. No person may operate an ultralight vehicle when the flight visibility or distance from clouds is less than that in the table found below. All operations in...

14 CFR 103.23 - Flight visibility and cloud clearance requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Flight visibility and cloud clearance... Flight visibility and cloud clearance requirements. No person may operate an ultralight vehicle when the flight visibility or distance from clouds is less than that in the table found below. All operations in...

14 CFR 103.23 - Flight visibility and cloud clearance requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Flight visibility and cloud clearance... Flight visibility and cloud clearance requirements. No person may operate an ultralight vehicle when the flight visibility or distance from clouds is less than that in the table found below. All operations in...

14 CFR 103.23 - Flight visibility and cloud clearance requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Flight visibility and cloud clearance... Flight visibility and cloud clearance requirements. No person may operate an ultralight vehicle when the flight visibility or distance from clouds is less than that in the table found below. All operations in...

14 CFR 103.23 - Flight visibility and cloud clearance requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Flight visibility and cloud clearance... Flight visibility and cloud clearance requirements. No person may operate an ultralight vehicle when the flight visibility or distance from clouds is less than that in the table found below. All operations in...

10 CFR 10.21 - Suspension of access authorization and/or employment clearance.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Suspension of access authorization and/or employment clearance. 10.21 Section 10.21 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING... Procedures § 10.21 Suspension of access authorization and/or employment clearance. In those cases where...

10 CFR 10.21 - Suspension of access authorization and/or employment clearance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Suspension of access authorization and/or employment clearance. 10.21 Section 10.21 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING... Procedures § 10.21 Suspension of access authorization and/or employment clearance. In those cases where...

10 CFR 10.21 - Suspension of access authorization and/or employment clearance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Suspension of access authorization and/or employment clearance. 10.21 Section 10.21 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING... Procedures § 10.21 Suspension of access authorization and/or employment clearance. In those cases where...

76 FR 17615 - Highway-Rail Grade Crossing; Safe Clearance

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-30

...-2006-25660] RIN 2137-AE69 & 2126-AB04 Highway-Rail Grade Crossing; Safe Clearance AGENCY: Pipeline and... PHMSA and FMCSA extend the comment period for the Highway-Rail Grade Crossing; Safe Clearance Notice of... Alliance (CVSA) requested that PHMSA and FMCSA extend the comment period for the Highway-Rail Grade...

An Evaluation of the Venous Equilibrium Model for Hepatic Clearance using Isolated Perfused Rainbow Trout Livers

EPA Science Inventory

The venous equilibrium model is widely used to describe hepatic clearance (CLH) of chemicals metabolized by the liver. If chemical delivery to the tissue does not limit CLH, this model predicts that CLH will approximately equal the product of intrinsic metabolic clearance and a t...

77 FR 56865 - Agency Information Collection Activities: Proposed Collection; Comment Request; Generic Clearance...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-14

... Collection Activities: Proposed Collection; Comment Request; Generic Clearance for Cognitive, Pilot and Field... information collection clearance that will allow BJS to conduct a variety of cognitive, pilot, and field test... each new or modified data collection, BJS will engage in cognitive, pilot and field test activities to...

14 CFR 99.17 - Deviation from flight plans and ATC clearances and instructions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Deviation from flight plans and ATC clearances and instructions. 99.17 Section 99.17 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... TRAFFIC General § 99.17 Deviation from flight plans and ATC clearances and instructions. (a) No pilot may...

48 CFR 1432.502-2 - Contract finance office clearance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract finance office clearance. 1432.502-2 Section 1432.502-2 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Progress Payments Based on Costs 1432.502-2 Contract finance office clearance. The CO shall...

Intelligent Engine Systems: HPT Clearance Control

NASA Technical Reports Server (NTRS)

2008-01-01

The Advanced Thermally Actuated Clearance Control System underwent several studies. Improved flow path isolation quantified what can be gained by making the HPT case nearly adiabatic. The best method of heat transfer was established, and finally two different borrowed air cooling circuits were evaluated to be used for the HPT Active Clearance Control System.

14 CFR 29.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground clearance: tail rotor guard. 29.411 Section 29.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 29.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

14 CFR 27.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground clearance: tail rotor guard. 27.411 Section 27.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 27.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

14 CFR 27.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ground clearance: tail rotor guard. 27.411 Section 27.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 27.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

14 CFR 29.411 - Ground clearance: tail rotor guard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ground clearance: tail rotor guard. 29.411 Section 29.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... System Loads § 29.411 Ground clearance: tail rotor guard. (a) It must be impossible for the tail rotor to...

31 CFR 205.20 - What is a clearance pattern?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., unless additional data is required to accurately represent the flow of Federal funds. (e) If a State uses... FEDERAL-STATE FUNDS TRANSFERS Rules Applicable to Federal Assistance Programs Included in a Treasury-State Agreement § 205.20 What is a clearance pattern? States use clearance patterns to project when funds are paid...

Assessment of the operating characteristics of the SSME LOX turbopump pump-end bearing

NASA Technical Reports Server (NTRS)

New, L. S.; Tiller, B. K.

1984-01-01

A bearing/shaft model of the SSME LOX turbopump was developed using the SHABERTH bearing/shaft math modeling computer code. A previously developed bearing/shaft thermal model of the SSME LOX turbopump turbine and bearing was used in conjunction with SHABERTH to evaluate the thermomechanical operating characteristics of the LOX turbopump end bearings. Results show that for the two unmounted diametrical clearances evaluated (4.0 mils and 6.3 mils), the inboard pump end bearing supports about 81% of the isolator load for the small clearance and 77% of the isolator load for the larger clearance. Bearing clearance changes due to thermal effects were 40% for the 4.0 mil diametrical clearance case and 19% for the 6.3 mil clearance case evaluated. The thermal analysis included evaluation of bearing temperatures for a subcooled case and a saturated case. Results indicate that no drastic temperature change occurred between the two cases. Since the rolling element and race surfaces of the subcooled case were at temperatures sufficiently high enough to be vapor blanketed, exceeding saturation temperature at the bearing inlet did not increase surface temperatures greatly.

Aerodynamic analysis of Audi A4 Sedan using CFD

NASA Astrophysics Data System (ADS)

Birwa, S. K.; Rathi, N.; Gupta, R.

2013-04-01

This paper presents the aerodynamic influence of velocity and ground clearance for Audi A4 Sedan. The topology of the test vehicle was modeled using CATIA P3 V5 R17. ANSYS FLUENT 12 was the CFD solver employed in this study. The distribution of pressure and velocity was obtained. The velocities were 30, 40, 50 and 60 m/s and ground clearances were 76.2 mm,101.6 mm,127 mm and 152.4 mm. The simulation results were compared with the available resources. It was found that the drag coefficient decreases with the velocity increasing from 30 to 60 m/s and increases with the ground clearance from 101.6 mm to 152.4 mm. Further decrease in ground clearance showed no effect on the value of coefficient of drag. The lift coefficient was found to decrease firstly with ground clearance from 152.4 mm to 101.6 mm, and then increase from 101.6 mm to 76.2 mm. Both the lift coefficient and drag coefficient was found to be minimum for the ground clearance of 101.6 mm as designed by the company.

Dialyzer performance in the clinic: comparison of six low-flux membranes.

PubMed

Kerr, P G; Lo, A; Chin, M m; Atkins, R C

1999-09-01

The aim of this study is to assess the clinical performance of 6 different low-flux dialysis membranes under steady-state conditions in terms of urea and phosphate clearances. Ten stable hemodialysis patients were examined. The following dialyzers were studied, all in 1.5- to 1.6-m2 format: cuprammonium, cellulose acetate, cellulose diacetate, hemophane, polysulfone (low-flux), and polysynthane. The following parameters were examined: urea reduction ratio, phosphate reduction ratio, "instantaneous dialyzer clearance" for urea and phosphate, and total amount of urea and phosphate removed in the dialysate over a 1-week (three dialyses) period. Although there were differences between the membranes, all produced results within a narrow range. There was no one membrane that produced superior clearances in all categories. The cellulose acetate membrane was the least satisfactory membrane. Phosphate clearances were at best one third that of urea clearances. When choosing a low-flux dialysis membrane, urea and phosphate clearances are so similar amongst different membranes that other criteria are likely to have a greater influence on the choice of membrane.

Nano-Advantage in Enhanced Drug Delivery with Biodegradable Nanoparticles: Contribution of Reduced Clearance

PubMed Central

Kadam, Rajendra S.; Bourne, David W. A.

2012-01-01

The aim of this study was to investigate the contribution of reduced apparent clearance to the enhanced exposure reported for biodegradable nanoparticles after extravascular and intravascular routes of administration. Plasma concentration profiles for drug and nanoparticle formulations after administration by intravenous, intraduodenal, and oral routes were extracted from the literature. Data were fit to pharmacokinetic models using BOOMER. The compartmental pharmacokinetic analysis of literature data for six drugs (camptothecin, 9-nitrocamptothecin, epirubicin, vinpocetine, clozapine, and cyclosporine) showed that the encapsulation of drug molecules in nanoparticles significantly reduced the apparent clearance and prolonged the apparent circulation half-life compared with those for the plain drug. Positively charged nanoparticles assessed in this study had lower apparent clearance, lower elimination rate constant values, and longer apparent circulation half-life than neutral and negatively charged nanoparticles. After oral administration, a reduction in apparent clearance contributed substantially to elevations in plasma drug exposure with nanoparticles. For the drugs and delivery systems examined, the nano-advantage in drug delivery enhancement can be explained, in part, by reduced clearance. PMID:22498894

Experimental studies on the effect of automation on pilot situational awareness in the datalink ATC environment

NASA Technical Reports Server (NTRS)

Hahn, Edward C.; Hansman, R. J., Jr.

1992-01-01

An experiment to study how automation, when used in conjunction with datalink for the delivery of ATC clearance amendments, affects the situational awareness of aircrews was conducted. The study was focused on the relationship of situational awareness to automated Flight Management System (FMS) programming of datalinked clearances and the readback of ATC clearances. Situational awareness was tested by issuing nominally unacceptable ATC clearances and measuring whether the error was detected by the subject pilots. The experiment also varied the mode of clearance delivery: Verbal, Textual, and Graphical. The error detection performance and pilot preference results indicate that the automated programming of the FMS may be superior to manual programming. It is believed that automated FMS programming may relieve some of the cognitive load, allowing pilots to concentrate on the strategic implications of a clearance amendment. Also, readback appears to have value, but the small sample size precludes a definite conclusion. Furthermore, because textual and graphical modes of delivery offer different but complementary advantages for cognitive processing, a combination of these modes of delivery may be advantageous in a datalink presentation.

Nanoparticle-macrophage interactions: A balance between clearance and cell-specific targeting

PubMed Central

Rattan, Rahul; Bhattacharjee, Somnath; Zong, Hong; Swain, Corban; Siddiqui, Muneeb A.; Visovatti, Scott H.; Kanthi, Yogendra; Desai, Sajani; Pinsky, David J.; Goonewardena, Sascha N.

2017-01-01

The surface properties of nanoparticles (NPs) are a major factor that influences how these nanomaterials interact with biological systems. Interactions between NPs and macrophages of the reticuloendothelial system (RES) can reduce the efficacy of NP diagnostics and therapeutics. Traditionally, to limit NP clearance by the RES system, the NP surface is neutralized with molecules like poly(ethylene glycol) (PEG) which are known to resist protein adsorption and RES clearance. Unfortunately, PEG modification is not without drawbacks including difficulties with the synthesis and associations with immune reactions. To overcome some of these obstacles, we neutralized the NP surface by acetylation and compared this modification to PEGylation for RES clearance and tumor-specific targeting. We found that acetylation was comparable to PEGylation in reducing RES clearance. Additionally, we found that dendrimer acetylation did not impact folic acid (FA)-mediated targeting of tumor cells whereas PEG surface modification reduced the targeting ability of the NP. These results clarify the impact of different NP surface modifications on RES clearance and cell-specific targeting and provide insights into the design of more effective NPs. PMID:28705434

Use of scintigraphy for the determination of mucociliary clearance rates in normal, sedated, diseased and exercised horses.

PubMed Central

Willoughby, R A; Ecker, G L; McKee, S L; Riddolls, L J

1991-01-01

Mucociliary clearance rates from the trachea were determined in normal, sedated, diseased and exercised horses from scintigraphs obtained after an injection of technetium-99m sulphide colloid into the tracheal lumen. The group mean tracheal clearance rate of eight clinically normal horses during 42 trials was 2.06 +/- 0.38 cm/min. Significant between horse differences were found (p less than 0.05). When six and seven of these horses were given xylazine and detomidine hydrochloride, respectively, mean group tracheal clearance rates dropped significantly (p less than 0.05). The decreases from each normal horse's mean tracheal clearance rate ranged from 18 to 54%. There did not appear to be a difference between the tracheal clearance rates (TCRs) of the normal horses and those with chronic respiratory disease. Postexercise evaluations were not significantly different from the pre-exercise TCRs in three clinically normal horses and three horses with chronic obstructive pulmonary disease (p greater than 0.05). This minimally invasive scintigraphic technique for determining TCRs has proved to be useful and reliable. Images Fig. 1. PMID:1790485

Lung clearance of /sup 99m/Tc-DTPA in patients with acute lung injury and pulmonary edema

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

Coates, G.; O'Brodovich, H.; Dolovich, M.

1988-07-01

Several acute and chronic conditions that alter the integrity of the pulmonary epithelium increased the rate of absorption or clearance into the circulation of small solutes deposited in the alveoli. Technetium 99m diethylenetriamine pentaacetic acid can be deposited in the lungs as a submicronic aerosol and its rate of clearance measured with a gamma camera or simple probe. This clearance technique is currently being used to evaluate patients who have developed pulmonary edema and also to detect those patients from a high risk group who are likely to develop adult respiratory distress syndrome (ARDS). Its role in the evaluation ofmore » patients with pulmonary edema is still under active investigation. It is clear that a single measurement in patients who smoke is not useful, but repeated measurements may provide important information. The lung clearance measurement is very sensitive to changes in epithelial integrity but is not specific for ARDS. It may be most useful in combination with other predictive tests or when the clearance rate is normal. 54 references.« less

Automatic Rail Extraction and Celarance Check with a Point Cloud Captured by Mls in a Railway

NASA Astrophysics Data System (ADS)

Niina, Y.; Honma, R.; Honma, Y.; Kondo, K.; Tsuji, K.; Hiramatsu, T.; Oketani, E.

2018-05-01

Recently, MLS (Mobile Laser Scanning) has been successfully used in a road maintenance. In this paper, we present the application of MLS for the inspection of clearance along railway tracks of West Japan Railway Company. Point clouds around the track are captured by MLS mounted on a bogie and rail position can be determined by matching the shape of the ideal rail head with respect to the point cloud by ICP algorithm. A clearance check is executed automatically with virtual clearance model laid along the extracted rail. As a result of evaluation, the accuracy of extracting rail positions is less than 3 mm. With respect to the automatic clearance check, the objects inside the clearance and the ones related to a contact line is successfully detected by visual confirmation.

Adaptive Development

NASA Technical Reports Server (NTRS)

2005-01-01

The goal of this research is to develop and demonstrate innovative adaptive seal technologies that can lead to dramatic improvements in engine performance, life, range, and emissions, and enhance operability for next generation gas turbine engines. This work is concentrated on the development of self-adaptive clearance control systems for gas turbine engines. Researchers have targeted the high-pressure turbine (HPT) blade tip seal location for following reasons: Current active clearance control (ACC) systems (e.g., thermal case-cooling schemes) cannot respond to blade tip clearance changes due to mechanical, thermal, and aerodynamic loads. As such they are prone to wear due to the required tight running clearances during operation. Blade tip seal wear (increased clearances) reduces engine efficiency, performance, and service life. Adaptive sealing technology research has inherent impact on all envisioned 21st century propulsion systems (e.g. distributed vectored, hybrid and electric drive propulsion concepts).

Further Characterization of an Active Clearance Control Concept

NASA Technical Reports Server (NTRS)

Taylor, Shawn C.; Steinetz, Bruce M.; Oswald, Jay J.

2007-01-01

A new test chamber and precision hydraulic actuation system were incorporated into an active clearance control (ACC) test rig at NASA Glenn Research Center. Using the improved system, a fast-acting, mechanically-actuated, ACC concept was evaluated at engine simulated temperatures and pressure differentials up to 1140 F and 120 psig, on the basis of secondary seal leakage and kinematic controllability. During testing, the ACC concept tracked a simulated flight clearance transient profile at 1140 F, 120 psig, with a maximum error of only 0.0012 in. Comparison of average dynamic leakage of the system with average static leakage did not show significant differences between the two operating conditions. Calculated effective clearance values for the rig were approximately 0.0002 in. at 120 psig, well below the industry specified effective clearance threshold of 0.001 in.

Shear joint capability versus bolt clearance

NASA Technical Reports Server (NTRS)

Lee, H. M.

1992-01-01

The results of a conservative analysis approach into the determination of shear joint strength capability for typical space-flight hardware as a function of the bolt-hole clearance specified in the design are presented. These joints are comprised of high-strength steel fasteners and abutments constructed of aluminum alloys familiar to the aerospace industry. A general analytical expression was first arrived at which relates bolt-hole clearance to the bolt shear load required to place all joint fasteners into a shear transferring position. Extension of this work allowed the analytical development of joint load capability as a function of the number of fasteners, shear strength of the bolt, bolt-hole clearance, and the desired factor of safety. Analysis results clearly indicate that a typical space-flight hardware joint can withstand significant loading when less than ideal bolt hole clearances are used in the design.

Accuracy of indocyanine green pulse spectrophotometry clearance test for liver function prediction in transplanted patients

PubMed Central

Hsieh, Chung-Bao; Chen, Chung-Jueng; Chen, Teng-Wei; Yu, Jyh-Cherng; Shen, Kuo-Liang; Chang, Tzu-Ming; Liu, Yao-Chi

2004-01-01

AIM: To investigate whether the non-invasive real-time Indocynine green (ICG) clearance is a sensitive index of liver viability in patients before, during, and after liver transplantation. METHODS: Thirteen patients were studied, two before, three during, and eight following liver transplantation, with two patients suffering acute rejection. The conventional invasive ICG clearance test and ICG pulse spectrophotometry non-invasive real-time ICG clearance test were performed simultaneously. Using linear regression analysis we tested the correlation between these two methods. The transplantation condition of these patients and serum total bilirubin (T. Bil), alanine aminotransferase (ALT), and platelet count were also evaluated. RESULTS: The correlation between these two methods was excellent (r2 = 0.977). CONCLUSION: ICG pulse spectrophotometry clearance is a quick, non-invasive, and reliable liver function test in transplantation patients. PMID:15285026

33 CFR 66.01-50 - Protection of private aids to navigation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Protection of private aids to... SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Aids to Navigation Other Than Federal or State § 66.01-50 Protection of private aids to navigation. Private aids to navigation lawfully maintained under...

33 CFR 66.01-50 - Protection of private aids to navigation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Protection of private aids to... SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Aids to Navigation Other Than Federal or State § 66.01-50 Protection of private aids to navigation. Private aids to navigation lawfully maintained under...

33 CFR 67.35-10 - Private aids to navigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications § 67.35-10...

33 CFR 67.35-10 - Private aids to navigation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications § 67.35-10...

33 CFR 66.05-25 - Change and modification of State aids to navigation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... aids to navigation. 66.05-25 Section 66.05-25 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-25 Change and modification of State aids to navigation. Wherever a State Administrator determines the...

33 CFR 66.01-50 - Protection of private aids to navigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Protection of private aids to... SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Aids to Navigation Other Than Federal or State § 66.01-50 Protection of private aids to navigation. Private aids to navigation lawfully maintained under...

33 CFR 66.05-25 - Change and modification of State aids to navigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... aids to navigation. 66.05-25 Section 66.05-25 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-25 Change and modification of State aids to navigation. Wherever a State Administrator determines the...

33 CFR 67.35-10 - Private aids to navigation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications § 67.35-10...

33 CFR 67.35-10 - Private aids to navigation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications § 67.35-10...

33 CFR 66.01-50 - Protection of private aids to navigation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Protection of private aids to... SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Aids to Navigation Other Than Federal or State § 66.01-50 Protection of private aids to navigation. Private aids to navigation lawfully maintained under...

33 CFR 66.05-25 - Change and modification of State aids to navigation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... aids to navigation. 66.05-25 Section 66.05-25 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-25 Change and modification of State aids to navigation. Wherever a State Administrator determines the...

33 CFR 66.05-25 - Change and modification of State aids to navigation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... aids to navigation. 66.05-25 Section 66.05-25 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-25 Change and modification of State aids to navigation. Wherever a State Administrator determines the...

33 CFR 67.35-10 - Private aids to navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications § 67.35-10...

33 CFR 66.01-50 - Protection of private aids to navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Protection of private aids to... SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION Aids to Navigation Other Than Federal or State § 66.01-50 Protection of private aids to navigation. Private aids to navigation lawfully maintained under...

33 CFR 66.05-25 - Change and modification of State aids to navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... aids to navigation. 66.05-25 Section 66.05-25 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-25 Change and modification of State aids to navigation. Wherever a State Administrator determines the...

Solute clearance measurement in the assessment of dialysis adequacy among African continuous ambulatory peritoneal dialysis patients.

PubMed

Abdu, Aliyu; Naidoo, Sagren; Malgas, Shirin; Naicker, Jocelyn T; Paget, Graham; Naicker, Saraladevi

2015-01-01

Solute clearance measurement is an objective means of quantifying the dose of peritoneal dialysis (PD). Despite continued debate on the interpretation and precise prognostic value of small solute clearance in PD patients, guidelines based on solute clearance values are common in clinical practice. There is limited information on the solute clearance indices and PD adequacy parameters among this predominantly low socioeconomic status PD population. We investigated the solute clearance among continuous ambulatory peritoneal dialysis (CAPD) patients at the Charlotte Maxeke Johannesburg Academic Hospital and its relationship with other parameters of PD adequacy. Seventy patients on CAPD were studied in this cross-sectional study. Solute clearance was assessed using urea clearance (Kt/V). Linear regression analysis was used to determine factors associated with solute clearance, while analysis of variance was used to test the influence of weekly Kt/V on blood pressure (BP), hemoglobin (Hb) and other biochemical parameters. The mean age of the study population was 37.9 ± 12.4 years, 43% were females and 86% were black Africans. The mean duration on CAPD was 19.7 ± 20.8 months. Mean systolic and diastolic BP were 144 ± 28 and 92 ± 17 mm Hg, respectively. The mean Hb was 11.1 ± 2.2 g/dL and the mean weekly Kt/V was 1.7 ± 0.3. Factors like systolic BP, Hb level, serum levels of cholesterol, calcium, phosphate, parathyroid hormone and albumin were not significantly associated with the weekly Kt/V. We conclude that the dose of PD received by the majority of our patients in terms of the weekly Kt/V is within the recommended values and that this finding is significant considering the low socioeconomic background of our patients. There is no significant association between Kt/V and other indices of dialysis adequacy.

Early lactate clearance is associated with biomarkers of inflammation, coagulation, apoptosis, organ dysfunction and mortality in severe sepsis and septic shock

PubMed Central

2010-01-01

Background Lactate clearance, a surrogate for the magnitude and duration of global tissue hypoxia, is used diagnostically, therapeutically and prognostically. This study examined the association of early lactate clearance with selected inflammatory, coagulation, apoptosis response biomarkers and organ dysfunction scores in severe sepsis and septic shock. Methods Measurements of serum arterial lactate, biomarkers (interleukin-1 receptor antagonist, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor-alpha, intercellular adhesion molecule-1, high mobility group box-1, D-Dimer and caspase-3), and organ dysfunction scores (Acute Physiology and Chronic Health Evaluation II, Simplified Acute Physiology Score II, Multiple Organ Dysfunction Score, and Sequential Organ Failure Assessment) were obtained in conjunction with a prospective, randomized study examining early goal-directed therapy in severe sepsis and septic shock patients presenting to the emergency department (ED). Lactate clearance was defined as the percent change in lactate levels after six hours from a baseline measurement in the ED. Results Two-hundred and twenty patients, age 65.0 +/- 17.1 years, were examined, with an overall lactate clearance of 35.5 +/- 43.1% and in-hospital mortality rate of 35.0%. Patients were divided into four quartiles of lactate clearance, -24.3 +/- 42.3, 30.1 +/- 7.5, 53.4 +/- 6.6, and 75.1 +/- 7.1%, respectively (p < 0.01). The mean levels of all biomarkers and organ dysfunction scores over 72 hours were significantly lower with higher lactate clearance quartiles (p < 0.01). There was a significant decreased in-hospital, 28-day, and 60-day mortality in the higher lactate clearance quartiles (p < 0.01). Conclusions Early lactate clearance as a surrogate for the resolution of global tissue hypoxia is significantly associated with decreased levels of biomarkers, improvement in organ dysfunction and outcome in severe sepsis and septic shock. PMID:20181046

pH modulation and salivary sugar clearance of different chocolates in children: A randomized clinical trial.

PubMed

Nirmala, Svsg; Quadar, Mohammed Akhil; Veluru, Sindhuri

2016-01-01

Sugars that occur naturally in foods and those added in processed foods may act as the source for fermentable carbohydrates and may initiate caries process. Among all the foods consumed by children, chocolates form an important constituent. A wide variety of chocolates are available in the Indian market and very few studies have compared their acidogenicity and salivary sugar clearance. To compare the acidogenicity and salivary sugar clearance of 6 different commercially available chocolates in the Indian market. Thirty subjects aged 10-15 years were selected randomly from one of the available public schools in Nellore city. Six commercially available chocolates in the Indian market were divided into three groups, unfilled (dark and milk chocolate), filled (wafer and fruit and nuts chocolate), and candy (hard milk and mango-flavored candy) groups. Plaque pH values and salivary sugar clearance rates are assessed at baseline, 5, 10, 15, 20, and 30 min after consumption. All the data obtained were statistically evaluated using independent sample t-test and one-way ANOVA for multiple group comparisons. Mango-flavored candy had maximum fall in plaque pH and least fall in plaque pH was recorded with milk chocolate. Fruit and nuts chocolate had a maximum clearance of salivary sugar and least fall in the salivary sugar clearance was recorded with dark chocolate. When the plaque pH and salivary sugar clearance of all the chocolates were assessed, it was seen that the values were statistically significant at all the time intervals (P < 0.05). Dark chocolate had a high fall in pH and milk chocolate had low salivary sugar clearance which signifies that unfilled chocolates are more cariogenic than other chocolates. Even though mango-flavored candy had maximum fall in plaque pH, its salivary sugar clearance was high.

Environmental factors affecting antipyrine metabolism in London factory and office workers.

PubMed Central

Fraser, H S; Mucklow, J C; Bulpitt, C J; Kahn, C; Mould, G; Dollery, C T

1979-01-01

1 Measurements of antipyrine clearance in saliva have been made in 128 London factory and office workers. 2 Mean antipyrine clearance in 56 Asian immigrants was 40% slower than in 72 White subjects. 3 Although dietary differences existed between the two groups, analysis of their effect independently of race was impossible since all but one of the vegetarians were Asian and the non-vegetarians were nearly all White. 4 In the White subjects, use of the oral contraceptive reduced clearance by 38% in women, while cigarette smoking increase clearance by 38% in men. PMID:427001

33 CFR 66.05-35 - Private aids to navigation other than State owned.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Private aids to navigation other... HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-35 Private aids to navigation other than State owned. (a) No person, public body or other instrumentality not...

33 CFR 66.05-35 - Private aids to navigation other than State owned.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Private aids to navigation other... HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-35 Private aids to navigation other than State owned. (a) No person, public body or other instrumentality not...

33 CFR 66.05-35 - Private aids to navigation other than State owned.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Private aids to navigation other... HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-35 Private aids to navigation other than State owned. (a) No person, public body or other instrumentality not...

33 CFR 66.05-35 - Private aids to navigation other than State owned.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Private aids to navigation other... HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-35 Private aids to navigation other than State owned. (a) No person, public body or other instrumentality not...

33 CFR 66.05-35 - Private aids to navigation other than State owned.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Private aids to navigation other... HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-35 Private aids to navigation other than State owned. (a) No person, public body or other instrumentality not...

Tip clearance effects on loads and performances of semi-open impeller centrifugal pumps at different specific speeds

NASA Astrophysics Data System (ADS)

Boitel, G.; Fedala, D.; Myon, N.

2016-11-01

Relevant industrial standards or customer's specifications could strictly forbid any device adjusting the axial rotor/stator position, so that tip clearance between semi-open impeller and casing might become a result of the pump machining tolerances and assembling process, leading to big tip clearance variations compared to its nominal value. Consequently, large disparities of global performances (head, power, efficiency) and axial loads are observed with high risk of both specifications noncompliance and bearing damages. This work aims at quantifying these variations by taking into account tip clearance value and pump specific speed. Computational Fluid Dynamics is used to investigate this phenomenon by means of steady simulations led on a semi-open centrifugal pump numerical model including secondary flows, based on a k-omega SST turbulence model. Four different specific speed pump sizes are simulated (from 8 to 50, SI units), with three tip clearances for each size on a wide flow range (from 40% to 120% of the best efficiency point). The numerical results clearly show that head, power and efficiency increase as the tip clearance decreases for the whole flow range. This effect is more significant when the specific speed is low. Meanwhile, the resulting axial thrust on the impeller is very sensitive to the tip clearance and can even lead to direction inversion.

Comparison of trout hepatocytes and liver S9 fractions as in ...

EPA Pesticide Factsheets

Isolated hepatocytes and liver S9 fractions have been used to collect in vitro biotransformation data for fish as a means of improving modeled estimates of chemical bioaccumulation. To date, however, there have been few direct comparisons of these two methods. In the present study, cryopreserved trout hepatocytes were used to measure in vitro intrinsic clearance rates for 6 polycyclic aromatic hydrocarbons (PAHs). These rates were extrapolated to estimates of in vivo intrinsic clearance and used as inputs to a well-stirred liver model to predict hepatic clearance. Predicted rates of hepatic clearance were then evaluated by comparison to measured rates determined previously using isolated perfused livers. Hepatic clearance rates predicted using hepatocytes were in good agreement with measured values (< 2.1 fold difference for 5 of 6 compounds) under two competing binding assumptions. These findings, which may be attributed in part to high rates of PAH metabolism, are similar to those obtained previously using data from liver S9 fractions. For one compound (benzo[a]pyrene), the in vivo intrinsic clearance rate calculated using S9 data was 10-fold higher than that determined using hepatocytes, possibly due to a diffusion limitation on cellular uptake. Generally, however, there was good agreement between calculated in vivo intrinsic clearance rates obtained using either in vitro test system. These results suggest that both systems can be used to improve

Investigation of the flow in the impeller side clearances of a centrifugal pump with volute casing

NASA Astrophysics Data System (ADS)

Will, Björn-Christian; Benra, Friedrich-Karl; Dohmen, Hans-Josef

2012-06-01

The paper is concerned with the fluid flow in the impeller side clearances of a centrifugal pump with volute casing. The flow conditions in these small axial gaps are of significant importance for a number of effects such as disk friction, leakage losses or hydraulic axial thrust to name but a few. In the investigated single stage pump, the flow pattern in the volute turns out to be asymmetric even at design flow rate. To gain a detailed insight into the flow structure, numerical simulations of the complete pump including the impeller side clearances are accomplished. Additionally, the hydraulic head and the radial pressure distributions in the impeller side clearances are measured and compared with the numerical results. Two configurations of the impeller, either with or without balancing holes, are examined. Moreover, three different operating points, i.e.: design point, part load or overload conditions are considered. In addition, analytical calculations are accomplished to determine the pressure distributions in the impeller side clearances. If accurate boundary conditions are available, the 1D flow models used in this paper can provide reasonable results for the radial static pressure distribution in the impeller side clearances. Furthermore, a counter rotating wake region develops in the rear impeller side clearances in absence of balancing holes which severely affects the inflow and outflow conditions of the cavity in circumferential direction.

Domiciliary humidification improves lung mucociliary clearance in patients with bronchiectasis.

PubMed

Hasani, A; Chapman, T H; McCool, D; Smith, R E; Dilworth, J P; Agnew, J E

2008-01-01

Inspired air humidification has been reported to show some benefit in bronchiectatic patients. We have investigated the possibility that one effect might be to enhance mucociliary clearance. Such enhancement might, if it occurs, help to lessen the risks of recurrent infective episodes. Using a radioaerosol technique, we measured lung mucociliary clearance before and after 7 days of domiciliary humidification. Patients inhaled high flow saturated air at 37 degrees C via a patient-operated humidification nasal inhalation system for 3 h per day. We assessed tracheobronchial mucociliary clearance from the retention of (99m)Tc-labelled polystyrene tracer particles monitored for 6 h, with a follow-up 24-h reading. Ten out of 14 initially recruited patients (age 37-75 years; seven females) completed the study (two withdrew after their initial screening and two prior to the initial clearance test). Seven patients studied were non-smokers; three were ex-smokers (1-9 pack-years). Initial tracer radioaerosol distribution was closely similar between pre- and post-treatment. Following humidification, lung mucociliary clearance significantly improved, the area under the tracheobronchial retention curve decreased from 319 +/- 50 to 271 +/- 46%h (p < 0.07). Warm air humidification treatment improved lung mucociliary clearance in our bronchiectatic patients. Given this finding plus increasing laboratory and clinical interest in humidification mechanisms and effects, we believe further clinical trials of humidification therapy are desirable, coupled with analysis of humidification effects on mucus properties and transport.

Depressed reticuloendothelial clearance of platelets in rats after trauma.

PubMed

Kaplan, J E; Moon, D G; Minnear, F L; Saba, T M

1984-02-01

Platelet microembolization may contribute to microcirculatory and organ damage following trauma and shock. It is hypothesized that posttraumatic reticuloendothelial depression predisposes to such microembolization by failure to clear altered platelets from the circulation. The present study evaluated the short-term (1 h) clearance and organ localization of radiolabeled homologous damaged platelets in normal rats and in rats following sublethal Noble-Collip drum trauma. Platelets were collected in citrated platelet-rich plasma from normal rats and labeled with 51Cr in citrated saline. Platelets were altered by repeated centrifugation in protein-free medium. These platelets differed functionally and morphologically from normal platelets. Disappearance of iv injected damaged platelets conformed to a two-compartment exponential clearance. Velocity of clearance in the rapid compartment correlated with hepatic platelet localization, whereas velocity of clearance in the second compartment correlated with splenic platelet localization. Clearance rate of the rapid compartment was depressed at 1 h after trauma and elevated at 24 h. These changes were associated with a decrease in hepatic platelet localization at 1 h and an increase above normal at 24 h. Splenic platelet localization was decreased by 3 h following trauma. Pulmonary platelet localization was increased at all times following trauma. It is concluded that the posttrauma state is associated with a defect in the reticuloendothelial system clearance of altered platelets, which may augment embolization of platelets in the lung.

Physiological and Microfluorometric Studies of Reduction and Clearance of Retinal in Bleached Rod Photoreceptors

PubMed Central

Tsina, Efthymia; Chen, Chunhe; Koutalos, Yiannis; Ala-Laurila, Petri; Tsacopoulos, Marco; Wiggert, Barbara; Crouch, Rosalie K.; Cornwall, M. Carter

2004-01-01

The visual cycle comprises a sequence of reactions that regenerate the visual pigment in photoreceptors during dark adaptation, starting with the reduction of all-trans retinal to all-trans retinol and its clearance from photoreceptors. We have followed the reduction of retinal and clearance of retinol within bleached outer segments of red rods isolated from salamander retina by measuring its intrinsic fluorescence. Following exposure to a bright light (bleach), increasing fluorescence intensity was observed to propagate along the outer segments in a direction from the proximal region adjacent to the inner segment toward the distal tip. Peak retinol fluorescence was achieved after ∼30 min, after which it declined very slowly. Clearance of retinol fluorescence is considerably accelerated by the presence of the exogenous lipophilic substances IRBP (interphotoreceptor retinoid binding protein) and serum albumin. We have used simultaneous fluorometric and electrophysiological measurements to compare the rate of reduction of all-trans retinal to all-trans retinol to the rate of recovery of flash response amplitude in these cells in the presence and absence of IRBP. We find that flash response recovery in rods is modestly accelerated in the presence of extracellular IRBP. These results suggest such substances may participate in the clearance of retinoids from rod photoreceptors, and that this clearance, at least in rods, may facilitate dark adaptation by accelerating the clearance of photoproducts of bleaching. PMID:15452202

Methodological uncertainty in quantitative prediction of human hepatic clearance from in vitro experimental systems.

PubMed

Hallifax, D; Houston, J B

2009-03-01

Mechanistic prediction of unbound drug clearance from human hepatic microsomes and hepatocytes correlates with in vivo clearance but is both systematically low (10 - 20 % of in vivo clearance) and highly variable, based on detailed assessments of published studies. Metabolic capacity (Vmax) of commercially available human hepatic microsomes and cryopreserved hepatocytes is log-normally distributed within wide (30 - 150-fold) ranges; Km is also log-normally distributed and effectively independent of Vmax, implying considerable variability in intrinsic clearance. Despite wide overlap, average capacity is 2 - 20-fold (dependent on P450 enzyme) greater in microsomes than hepatocytes, when both are normalised (scaled to whole liver). The in vitro ranges contrast with relatively narrow ranges of clearance among clinical studies. The high in vitro variation probably reflects unresolved phenotypical variability among liver donors and practicalities in processing of human liver into in vitro systems. A significant contribution from the latter is supported by evidence of low reproducibility (several fold) of activity in cryopreserved hepatocytes and microsomes prepared from the same cells, between separate occasions of thawing of cells from the same liver. The large uncertainty which exists in human hepatic in vitro systems appears to dominate the overall uncertainty of in vitro-in vivo extrapolation, including uncertainties within scaling, modelling and drug dependent effects. As such, any notion of quantitative prediction of clearance appears severely challenged.

Cost-Effectiveness of Patient Navigation to Increase Adherence with Screening Colonoscopy Among Minority Individuals

PubMed Central

Ladabaum, Uri; Mannalithara, Ajitha; Jandorf, Lina; Itzkowitz, Steven H.

2015-01-01

Background Colorectal cancer (CRC) screening is underutilized by minority populations. Patient navigation increases adherence with screening colonoscopy. We estimated the cost-effectiveness of navigation for screening colonoscopy from the perspective of a payer seeking to improve population health. Methods We informed our validated model of CRC screening with inputs from navigation studies in New York City (population 43% African American, 49% Hispanic, 4% White, 4% Other; base case screening 40% without and 65% with navigation, navigation costs $29/colonoscopy completer, $21/non-completer, $3/non-navigated). We compared: 1) navigation vs. no navigation for one-time screening colonoscopy in unscreened persons age ≥50; 2) programs of colonoscopy with vs. without navigation, vs. fecal occult blood testing (FOBT) or immunochemical testing (FIT) for ages 50-80. Results In the base case: 1) one-time navigation gained quality-adjusted life-years (QALYs) and decreased costs; 2) longitudinal navigation cost $9,800/QALY gained vs. no navigation, and assuming comparable uptake rates, it cost $118,700/QALY gained vs. FOBT, but was less effective and more costly than FIT. Results were most dependent on screening participation rates and navigation costs: 1) assuming a 5% increase in screening uptake with navigation and navigation cost of $150/completer, one-time navigation cost $26,400/QALY gained; 2) longitudinal navigation with 75% colonoscopy uptake cost <$25,000/QALY gained vs. FIT when FIT uptake was <50%. Probabilistic sensitivity analyses did not alter the conclusions. Conclusions Navigation for screening colonoscopy appears to be cost-effective, and one-time navigation may be cost-saving. In emerging healthcare models that reward outcomes, payers should consider covering the costs of navigation for screening colonoscopy. PMID:25492455

Renal Clearance: Using an Interactive Activity to Visualize a Tricky Concept

ERIC Educational Resources Information Center

Hull, Kerry

2016-01-01

Renal clearance, the volume of blood cleared of a substance in a particular time period, is commonly recognized as one of the most difficult concepts in physiology. This difficulty may in part reflect the quantitative nature of renal clearance since many life sciences majors perceive that mathematics is irrelevant to their discipline. Students may…

20 CFR 655.150 - Interstate clearance of job order.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Interstate clearance of job order. 655.150... job order. (a) SWA posts in interstate clearance system. The SWA must promptly place the job order in... transmit a copy of its active job order to all States listed in the job order as anticipated worksites...

20 CFR 655.150 - Interstate clearance of job order.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false Interstate clearance of job order. 655.150... job order. (a) SWA posts in interstate clearance system. The SWA must promptly place the job order in... transmit a copy of its active job order to all States listed in the job order as anticipated worksites...

20 CFR 655.150 - Interstate clearance of job order.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Interstate clearance of job order. 655.150... job order. (a) SWA posts in interstate clearance system. The SWA must promptly place the job order in... transmit a copy of its active job order to all States listed in the job order as anticipated worksites...

20 CFR 655.150 - Interstate clearance of job order.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Interstate clearance of job order. 655.150... job order. (a) SWA posts in interstate clearance system. The SWA must promptly place the job order in... transmit a copy of its active job order to all States listed in the job order as anticipated worksites...

20 CFR 655.150 - Interstate clearance of job order.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false Interstate clearance of job order. 655.150... job order. (a) SWA posts in interstate clearance system. The SWA must promptly place the job order in... transmit a copy of its active job order to all States listed in the job order as anticipated worksites...

31 CFR 205.12 - What funding techniques may be used?

Code of Federal Regulations, 2011 CFR

2011-07-01

... that the State pays out each day. The projected amount paid out each day is determined by applying a clearance pattern to the total amount the State will disburse. (3) Average clearance means that a Federal Program Agency, on the dollar-weighted average day of clearance of a disbursement, transfers to a State a...

Aerial Refueling Clearance Initiation Request

DTIC Science & Technology

2016-07-14

and receiver agencies. The AR Clearance Initiation Request document recognizes the requirement for definitive aerial refueling agreements between...and contractual tanker support requests from one organization or nation to another. The AR Clearance Initiation Request document is not intended to...proprietary, sensitive, classified or otherwise restricted information. ARSAG documents, as prepared, are not DOD, MOD or NATO standards, but provide

14 CFR 105.17 - Flight visibility and clearance from cloud requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Flight visibility and clearance from cloud... Flight visibility and clearance from cloud requirements. No person may conduct a parachute operation, and...— (a) Into or through a cloud, or (b) When the flight visibility or the distance from any cloud is less...

14 CFR 105.17 - Flight visibility and clearance from cloud requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Flight visibility and clearance from cloud... Flight visibility and clearance from cloud requirements. No person may conduct a parachute operation, and...— (a) Into or through a cloud, or (b) When the flight visibility or the distance from any cloud is less...

14 CFR 105.17 - Flight visibility and clearance from cloud requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Flight visibility and clearance from cloud... Flight visibility and clearance from cloud requirements. No person may conduct a parachute operation, and...— (a) Into or through a cloud, or (b) When the flight visibility or the distance from any cloud is less...

14 CFR 105.17 - Flight visibility and clearance from cloud requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Flight visibility and clearance from cloud... Flight visibility and clearance from cloud requirements. No person may conduct a parachute operation, and...— (a) Into or through a cloud, or (b) When the flight visibility or the distance from any cloud is less...

14 CFR 105.17 - Flight visibility and clearance from cloud requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Flight visibility and clearance from cloud... Flight visibility and clearance from cloud requirements. No person may conduct a parachute operation, and...— (a) Into or through a cloud, or (b) When the flight visibility or the distance from any cloud is less...

33 CFR 149.510 - How do I get permission to establish an aid to navigation?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false How do I get permission to establish an aid to navigation? 149.510 Section 149.510 Navigation and Navigable Waters COAST GUARD... EQUIPMENT Aids to Navigation General § 149.510 How do I get permission to establish an aid to navigation? (a...

33 CFR 149.510 - How do I get permission to establish an aid to navigation?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false How do I get permission to establish an aid to navigation? 149.510 Section 149.510 Navigation and Navigable Waters COAST GUARD... EQUIPMENT Aids to Navigation General § 149.510 How do I get permission to establish an aid to navigation? (a...

33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

Terrain matching image pre-process and its format transform in autonomous underwater navigation

NASA Astrophysics Data System (ADS)

Cao, Xuejun; Zhang, Feizhou; Yang, Dongkai; Yang, Bogang

2007-06-01

Underwater passive navigation technology is one of the important development orientations in the field of modern navigation. With the advantage of high self-determination, stealth at sea, anti-jamming and high precision, passive navigation is completely meet with actual navigation requirements. Therefore passive navigation has become a specific navigating method for underwater vehicles. The scientists and researchers in the navigating field paid more attention to it. The underwater passive navigation can provide accurate navigation information with main Inertial Navigation System (INS) for a long period, such as location and speed. Along with the development of micro-electronics technology, the navigation of AUV is given priority to INS assisted with other navigation methods, such as terrain matching navigation. It can provide navigation ability for a long period, correct the errors of INS and make AUV not emerge from the seabed termly. With terrain matching navigation technique, in the assistance of digital charts and ocean geographical characteristics sensors, we carry through underwater image matching assistant navigation to obtain the higher location precision, therefore it is content with the requirement of underwater, long-term, high precision and all-weather of the navigation system for Autonomous Underwater Vehicles. Tertian-assistant navigation (TAN) is directly dependent on the image information (map information) in the navigating field to assist the primary navigation system according to the path appointed in advance. In TAN, a factor coordinative important with the system operation is precision and practicability of the storable images and the database which produce the image data. If the data used for characteristics are not suitable, the system navigation precision will be low. Comparing with terrain matching assistant navigation system, image matching navigation system is a kind of high precision and low cost assistant navigation system, and its matching precision directly influences the final precision of integrated navigation system. Image matching assistant navigation is spatially matching and aiming at two underwater scenery images coming from two different sensors matriculating of the same scenery in order to confirm the relative displacement of the two images. In this way, we can obtain the vehicle's location in fiducial image known geographical relation, and the precise location information given from image matching location is transmitted to INS to eliminate its location error and greatly enhance the navigation precision of vehicle. Digital image data analysis and processing of image matching in underwater passive navigation is important. In regard to underwater geographic data analysis, we focus on the acquirement, disposal, analysis, expression and measurement of database information. These analysis items structure one of the important contents of underwater terrain matching and are propitious to know the seabed terrain configuration of navigation areas so that the best advantageous seabed terrain district and dependable navigation algorithm can be selected. In this way, we can improve the precision and reliability of terrain assistant navigation system. The pre-process and format transformation of digital image during underwater image matching are expatiated in this paper. The information of the terrain status in navigation areas need further study to provide the reliable data terrain characteristic and underwater overcast for navigation. Through realizing the choice of sea route, danger district prediction and navigating algorithm analysis, TAN can obtain more high location precision and probability, hence provide technological support for image matching of underwater passive navigation.

The effects of alcohol on spontaneous clearance of acute hepatitis C virus infection in females versus males.

PubMed

Tsui, Judith I; Mirzazadeh, Ali; Hahn, Judith A; Maher, Lisa; Bruneau, Julie; Grebely, Jason; Hellard, Margaret; Kim, Arthur Y; Shoukry, Naglaa H; Cox, Andrea L; Prins, Maria; Dore, Gregory J; Lauer, Georg; Lloyd, Andrew R; Page, Kimberly

2016-12-01

Approximately one quarter of persons exposed to hepatitis C virus (HCV) will spontaneously clear infection. We undertook this study to investigate the impact of alcohol on likelihood of HCV spontaneous viral clearance stratified by sex groups. Pooled data from an international collaboration of prospective observational studies of incident HIV and HCV infection in high-risk cohorts (the InC3 Study) was restricted to 411 persons (or 560.7 person-years of observation) with documented acute HCV infection and data regarding alcohol use. The predictor of interest was self-reported alcohol use at or after estimated date of incident HCV infection and the outcome was HCV spontaneous clearance. Sex stratified Cox proportional hazards models were used to evaluate the association between alcohol and spontaneous clearance, adjusting for age, race/ethnicity, and IFNL4 genotype. The median age was 28.5 years, 30.4% were women, 87.2% were white, and 71.8% reported alcohol use at or after incident infection. There were 89 (21.6%) cases of spontaneous clearance observed, 39 (31.2%) among women and 50 (17.5%) in men (p<0.01). Overall, spontaneous clearance occurred less frequently among participants who drank alcohol compared to those who did not drink (18.9% v. 28.5%, p=0.03). After adjustment for other covariates, alcohol was significantly and independently associated with lower relative hazards for spontaneous clearance of HCV in women (AHR=0.35; 95% CI: 0.19-0.66; p=0.001) but not in men (AHR=0.63; 95% CI: 0.36-1.09; p=0.10). Results indicate that abstaining from drinking alcohol may increase the likelihood of spontaneous clearance among women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Effects of Alcohol on Spontaneous Clearance of Acute Hepatitis C Virus Infection in Females versus Males

PubMed Central

Tsui, Judith I.; Mirzazadeh, Ali; Hahn, Judith A.; Maher, Lisa; Bruneau, Julie; Grebely, Jason; Hellard, Margaret; Kim, Arthur Y.; Shoukry, Naglaa H.; Cox, Andrea L.; Prins, Maria; Dore, Gregory; Lauer, Georg; Lloyd, Andrew; Page, Kimberly

2016-01-01

Background Approximately one quarter of persons exposed to hepatitis C virus (HCV) will spontaneously clear infection. We undertook this study to investigate the impact of alcohol on likelihood of HCV spontaneous viral clearance stratified by sex groups. Methods Pooled data from an international collaboration of prospective observational studies of incident HIV and HCV infection in high-risk cohorts (the InC3 Study) was restricted to 411 persons (or 560.7 person-years of observation) with documented acute HCV infection and data regarding alcohol use. The predictor of interest was self-reported alcohol use at or after estimated date of incident HCV infection and the outcome was HCV spontaneous clearance. Sex stratified Cox proportional hazards models were used to evaluate the association between alcohol and spontaneous clearance, adjusting for age, race/ethnicity, and IFNL4 genotype. Results The median age was 28.5 years, 30.4% were women, 87.2% were white, and 71.8% reported alcohol use at or after incident infection. There were 89 (21.6%) cases of spontaneous clearance observed, 39 (31.2%) among women and 50 (17.5%) in men (p<0.01). Overall, spontaneous clearance occurred less frequently among participants who drank alcohol compared to those who did not drink (18.9% v. 28.5%, p=0.03). After adjustment for other covariates, alcohol was significantly and independently associated with lower relative hazards for spontaneous clearance of HCV in women (AHR=0.35; 95% CI: 0.19-0.66; p=0.001) but not in men (AHR=0.63; 95% CI: 0.36-1.09; p=0.10). Conclusion Results indicate that abstaining from drinking alcohol may increase the likelihood of spontaneous clearance among women. PMID:27816863

Long-term clearance from small airways in subjects with ciliary dysfunction.

PubMed

Lindström, Maria; Falk, Rolf; Hjelte, Lena; Philipson, Klas; Svartengren, Magnus

2006-05-20

The objective of this study was to investigate if long-term clearance from small airways is dependent on normal ciliary function. Six young adults with primary ciliary dyskinesia (PCD) inhaled 111 Indium labelled Teflon particles of 4.2 microm geometric and 6.2 microm aerodynamic diameter with an extremely slow inhalation flow, 0.05 L/s. The inhalation method deposits particles mainly in the small conducting airways. Lung retention was measured immediately after inhalation and at four occasions up to 21 days after inhalation. Results were compared with data from ten healthy controls. For additional comparison three of the PCD subjects also inhaled the test particles with normal inhalation flow, 0.5 L/s, providing a more central deposition. The lung retention at 24 h in % of lung deposition (Ret24) was higher (p < 0.001) in the PCD subjects, 79 % (95% Confidence Interval, 67.6;90.6), compared to 49% (42.3;55.5) in the healthy controls. There was a significant clearance after 24 h both in the PCD subjects and in the healthy controls with equivalent clearance. The mean Ret24 with slow inhalation flow was 73.9 +/- 1.9% compared to 68.9 +/- 7.5% with normal inhalation flow in the three PCD subjects exposed twice. During day 7-21 the three PCD subjects exposed twice cleared 9% with normal flow, probably representing predominantly alveolar clearance, compared to 19% with slow inhalation flow, probably representing mainly small airway clearance. This study shows that despite ciliary dysfunction, clearance continues in the small airways beyond 24 h. There are apparently additional clearance mechanisms present in the small airways.

Noncontact Capacitive Clearance Control System For Laser Cutting Machines

NASA Astrophysics Data System (ADS)

Topkaya, Ahmet; Schmall, Karl-Heinz; Majoli, Ralf

1989-03-01

For a continuous high quality laser cut, it is necessary among other things to position the focal point of the laser beam correctly. This means that a constant clearance between the cutting head and the workpiece with a tolerance of +/- 0.Imm must he ensured. When cutting corrugated automobile bodysheet for example, a good quality cut can only be achieved with automatic clearance control. In the following, a method of automatic clearance control is described using the assistance of a noncontact capacitive sensor system. The copper nozzle of the laser cutting head acts as the electrode of the clearance sensor. The nozzle electrode and the workpiece build a small variable capacitance depending on the clearance. A change of clearance also changes the capacitance, which in turn influences a high frequency oscillator circuit. This shift in frequency is then converted into an analogue DC signal, which can be used to operate a servo motor control for the positioning of the laser cutting head in a closed loop servo system. Laser cutting heads with clearance sensor nozzles of different shapes, suited fur most applications in the industry, with focal lengths from 2.5" to 5" have been developed. They are capable to cut metal sheet from 0.2 to 12 mm of thickness, using CO2-lasers with output power up to 2.5 kW. For special applications involving difficult workpiece topographies in automobile production applications special "trunk" nozzles have been developed. For 5-axis cutting machines and robots, new laser cutting heads with integrated nozzle sensors in combination with a high dynamic Z-axis motor drive are in a stage of development.

Inhibition of cytochrome P450 enzymes by saturated and unsaturated fatty acids in human liver microsomes, characterization of enzyme kinetics in the presence of bovine serum albumin (0.1 and 1.0% w/v) and in vitro - in vivo extrapolation of hepatic clearance.

PubMed

Palacharla, Raghava Choudary; Uthukam, Venkatesham; Manoharan, Arunkumar; Ponnamaneni, Ranjith Kumar; Padala, Nagasurya Prakash; Boggavarapu, Rajesh Kumar; Bhyrapuneni, Gopinadh; Ajjala, Devender Reddy; Nirogi, Ramakrishna

2017-04-01

The objective of the study was to determine the effect of fatty acids on CYP enzymes and the effect of BSA on intrinsic clearance of probe substrates. The inhibitory effect of thirteen fatty acids including saturated, mono-unsaturated and polyunsaturated fatty acids on CYP enzymes, kinetic parameters and intrinsic clearance values of nine CYP marker probe substrate reactions in the absence and presence of BSA (0.1 and 1.0% w/v) were characterized in human liver microsomes. The results demonstrate that most of the unsaturated fatty acids showed marked inhibition towards CYP2C8 mediated amodiaquine N-deethylation followed by inhibition of CYP2C9 and CYP2B6 mediated activities. The addition of 0.1% BSA in the incubation markedly improved the unbound intrinsic clearance values of probe substrates by reducing the K m values with little or no effect on maximal velocity. The addition of BSA (0.1 and 1.0% w/v) did not influence the unbound intrinsic clearance of marker reactions for CYP2A6, and CYP3A4 enzymes. The addition of 0.1% w/v BSA is sufficient to determine the intrinsic clearance of marker probe reactions by metabolite formation approach. The predicted hepatic clearance values for the substrates using the well-stirred model, in the presence of BSA (0.1% BSA), are comparable to the in vivo hepatic clearance values. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of pregnancy on renal clearance of boron in rats given boric acid orally.

PubMed

Vaziri, N D; Oveisi, F; Culver, B D; Pahl, M V; Andersen, M E; Strong, P L; Murray, F J

2001-04-01

Boric acid (H(3)BO(3)) has been shown to cause developmental abnormalities in the offspring of pregnant rats. Comparative data on the renal clearance of boron (B) in rats and humans, both pregnant and nonpregnant, exposed to boric acid (BA) would reduce uncertainty in interspecies extrapolation from rats to humans. The purpose of this study was to evaluate the effect of pregnancy on the plasma half-life and renal clearance of boron in Sprague-Dawley rats given a single oral dose of boric acid. For the half-life study, nonpregnant and pregnant (gestation day 16) rats were given a single dose of 30 mg/kg of boric acid by gavage, and plasma samples were collected at 2-3 h intervals. The plasma half-life of boron was determined to be 2.9 +/- 0.2 and 3.2 +/- 0.3 h in nonpregnant and pregnant rats, respectively. In the clearance study, nonpregnant and pregnant (GD 16) rats were given a single gavage dose of 0.3, 3, or 30 mg/kg of boric acid. Boron clearance was slightly higher in pregnant rats (3.3 +/- 0.6, 3.2 +/- 0.5, and 3.4 +/- 0.5 ml/min/kg, respectively) compared to nonpregnant rats (3.1 +/- 0.8, 3.0 +/- 0.6, and 3.2 +/- 0.5 ml/min/kg, respectively), but the difference was not statistically significant and not dose-related. Boron clearance was less than creatinine clearance, suggesting tubular reabsorption in both groups. In conclusion, pregnancy did not appear to significantly alter the renal clearance or the plasma half-life of boron in Sprague-Dawley rats under the conditions of this study.

Pre-Departure Clearance (PDC): An Analysis of Aviation Safety Reporting System Reports Concerning PDC Related Errors

NASA Technical Reports Server (NTRS)

Montalyo, Michael L.; Lebacqz, J. Victor (Technical Monitor)

1994-01-01

Airlines operating in the United States are required to operate under instrument flight rules (EFR). Typically, a clearance is issued via voice transmission from clearance delivery at the departing airport. In 1990, the Federal Aviation Administration (FAA) began deployment of the Pre-Departure Clearance (PDC) system at 30 U.S. airports. The PDC system utilizes aeronautical datalink and Aircraft Communication and Reporting System (ACARS) to transmit departure clearances directly to the pilot. An objective of the PDC system is to provide an immediate reduction in voice congestion over the clearance delivery frequency. Participating airports report that this objective has been met. However, preliminary analysis of 42 Aviation Safety Reporting System (ASRS) reports has revealed problems in PDC procedures and formatting which have caused errors in the proper execution of the clearance. It must be acknowledged that this technology, along with other advancements on the flightdeck, is adding more responsibility to the crew and increasing the opportunity for error. The present study uses these findings as a basis for further coding and analysis of an additional 82 reports obtained from an ASRS database search. These reports indicate that clearances are often amended or exceptions are added in order to accommodate local ATC facilities. However, the onboard ACARS is limited in its ability to emphasize or highlight these changes which has resulted in altitude and heading deviations along with increases in ATC workload. Furthermore, few participating airports require any type of PDC receipt confirmation. In fact, 35% of all ASRS reports dealing with PDC's include failure to acquire the PDC at all. Consequently, this study examines pilots' suggestions contained in ASRS reports in order to develop recommendations to airlines and ATC facilities to help reduce the amount of incidents that occur.

Clinical evaluation of plasma insulin and C-peptide levels with 3 different high-flux dialyzers in diabetic patients on hemodialysis.

PubMed

Abe, M; Okada, K; Maruyama, T; Inoshita, A; Ikeda, K; Uto, E; Kikuchi, F; Matsumoto, K

2008-10-01

Changes in plasma immunoreactive insulin (IRI) and connecting-peptide immunoreactivity (CPR) concentrations during hemodialysis (HD) were evaluated in diabetic HD patients with 3 different high-flux membranes. The removal properties of the membranes were compared. In this prospective controlled study, 15 stable diabetic patients on HD were randomly selected for 6 HD sessions with 3 different membranes: polysulfone (PS), cellulose triacetate (CTA), and polymethylmethacrylate (PMMA). Blood samples were obtained from the blood tubing at the arterial (A) site at the beginning and end of the sixth HD session. At 60 minutes after dialysis initiation, blood samples were obtained from both the A and venous (V) sites of the dialyzer to investigate the clearance and removal properties of the membranes. The plasma IRI and CPR levels decreased significantly at each time point with all 3 membranes. IRI clearance with the PS membrane was significantly higher than that with the CTA and PMMA membranes. No difference was observed in the IRI reduction rate between the 3 membranes. CPR clearance and reduction rate with the PMMA membrane were lower than with the PS and CTA membranes. No significant difference was observed in serum creatinine clearance and reduction rates between the 3 membranes; however, serum urea nitrogen clearance was significantly lower with the PMMA membrane compared with the PS and CTA membranes. A significantly high beta2-microglobulin clearance and reduction rate was achieved in the order PS > CTA > PMMA. Plasma IRI and CPR are cleared by HD; their clearance rates differ with the dialyzer membranes. Plasma IRI clearance with the PS membrane is higher than that with the CTA and PMMA membranes.

Depression of in vivo clearance function of hepatic macrophage complement receptors following thermal injury.

PubMed

Cuddy, B G; Loegering, D J; Blumenstock, F A

1984-09-01

Previous studies have implicated a role for impaired hepatic macrophage blood clearance function in the increased susceptibility to infection caused by experimental thermal injury. The present study evaluated in vivo hepatic macrophage complement receptor clearance function as a possible factor contributing to impaired hepatic clearance after thermal injury. Rat erythrocytes treated with anti-erythrocyte serum (EA) were used as the test particle in rats. EA were rapidly removed from the circulation primarily by the liver and hepatic uptake of EA was greatly depressed in animals rendered C3 deficient by treatment with cobra venom factor. Thermal injury caused a large depression in the hepatic uptake of EA. It was shown that the depression in the binding of EA to hepatic macrophages was not due to decreased hepatic blood flow, decreased serum complement levels, or increased fluid phase C3b. Also, the depression of the hepatic uptake of EA incubated with serum prior to injection (EAC) was not different from that of EA after thermal injury. On this basis it was concluded that the impairment in binding of EA to the macrophages was at the cellular level and represented a depression in complement receptor clearance function. Additional studies showed that the injection of erythrocyte stroma, as a model of intravascular hemolysis, also depressed in vivo hepatic macrophage complement receptor clearance function. This latter finding suggests that the intravascular hemolysis caused by thermal injury may contribute to the depression of macrophage receptor function. The depression of hepatic macrophage complement receptor clearance function may contribute to the impaired bacterial clearance and increased susceptibility to infection following experimental thermal injury.

Pharmacokinetics of amoxycillin and clavulanic acid in haemodialysis patients following intravenous administration of Augmentin.

PubMed Central

Davies, B E; Boon, R; Horton, R; Reubi, F C; Descoeudres, C E

1988-01-01

1. Serum concentrations of amoxycillin and clavulanic acid were measured in patients with end-stage renal disease (ESRD) following intravenous administration of 1.2 g Augmentin. Augmentin was administered on a non-dialysis day and 2 h prior to a 4 h dialysis session. 2. The mean values of total serum clearance, mean residence time, volume of distribution at steady state, and terminal half-life for amoxycillin on the non-dialysis day were 14.4 ml min-1, 19.2 h, 14.9 l and 13.6 h, respectively. 3. The mean values of dialysis clearance, total serum clearance during dialysis, fractional drug removal during haemodialysis and half-life during dialysis for amoxycillin were 77.1 ml min-1, 91.5 ml min-1, 0.64 and 2.30 h, respectively. 4. The mean values of total serum clearance, mean residence time, volume of distribution at steady state, and terminal half-life for clavulanic acid on the non-dialysis day were 43.6 ml min-1, 4.4 h, 11.0 l and 3.05 h, respectively. 5. The mean values of dialysis clearance, total serum clearance during dialysis, fractional drug removal during haemodialysis and half-life during dialysis for clavulanic acid were 92.8 ml min-1, 136 ml min-1, 0.65 and 1.19 h, respectively. 6. The total serum clearance on the non-dialysis day, which represents non-renal clearance, was lower than that in normal subjects for both amoxycillin and clavulanic acid. These data would suggest some degree of hepatic impairment in patients with ESRD.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3190988

Nasal high flow clears anatomical dead space in upper airway models

PubMed Central

Celik, Gülnaz; Feng, Sheng; Bartenstein, Peter; Meyer, Gabriele; Eickelberg, Oliver; Schmid, Otmar; Tatkov, Stanislav

2015-01-01

Recent studies showed that nasal high flow (NHF) with or without supplemental oxygen can assist ventilation of patients with chronic respiratory and sleep disorders. The hypothesis of this study was to test whether NHF can clear dead space in two different models of the upper nasal airways. The first was a simple tube model consisting of a nozzle to simulate the nasal valve area, connected to a cylindrical tube to simulate the nasal cavity. The second was a more complex anatomically representative upper airway model, constructed from segmented CT-scan images of a healthy volunteer. After filling the models with tracer gases, NHF was delivered at rates of 15, 30, and 45 l/min. The tracer gas clearance was determined using dynamic infrared CO2 spectroscopy and 81mKr-gas radioactive gamma camera imaging. There was a similar tracer-gas clearance characteristic in the tube model and the upper airway model: clearance half-times were below 1.0 s and decreased with increasing NHF rates. For both models, the anterior compartments demonstrated faster clearance levels (half-times < 0.5 s) and the posterior sections showed slower clearance (half-times < 1.0 s). Both imaging methods showed similar flow-dependent tracer-gas clearance in the models. For the anatomically based model, there was complete tracer-gas removal from the nasal cavities within 1.0 s. The level of clearance in the nasal cavities increased by 1.8 ml/s for every 1.0 l/min increase in the rate of NHF. The study has demonstrated the fast-occurring clearance of nasal cavities by NHF therapy, which is capable of reducing of dead space rebreathing. PMID:25882385

Rare versus common variants in pharmacogenetics: SLCO1B1 variation and methotrexate disposition

PubMed Central

Ramsey, Laura B.; Bruun, Gitte H.; Yang, Wenjian; Treviño, Lisa R.; Vattathil, Selina; Scheet, Paul; Cheng, Cheng; Rosner, Gary L.; Giacomini, Kathleen M.; Fan, Yiping; Sparreboom, Alex; Mikkelsen, Torben S.; Corydon, Thomas J.; Pui, Ching-Hon; Evans, William E.; Relling, Mary V.

2012-01-01

Methotrexate is used to treat autoimmune diseases and malignancies, including acute lymphoblastic leukemia (ALL). Inter-individual variation in clearance of methotrexate results in heterogeneous systemic exposure, clinical efficacy, and toxicity. In a genome-wide association study of children with ALL, we identified SLCO1B1 as harboring multiple common polymorphisms associated with methotrexate clearance. The extent of influence of rare versus common variants on pharmacogenomic phenotypes remains largely unexplored. We tested the hypothesis that rare variants in SLCO1B1 could affect methotrexate clearance and compared the influence of common versus rare variants in addition to clinical covariates on clearance. From deep resequencing of SLCO1B1 exons in 699 children, we identified 93 SNPs, 15 of which were non-synonymous (NS). Three of these NS SNPs were common, with a minor allele frequency (MAF) >5%, one had low frequency (MAF 1%–5%), and 11 were rare (MAF <1%). NS SNPs (common or rare) predicted to be functionally damaging were more likely to be found among patients with the lowest methotrexate clearance than patients with high clearance. We verified lower function in vitro of four SLCO1B1 haplotypes that were associated with reduced methotrexate clearance. In a multivariate stepwise regression analysis adjusting for other genetic and non-genetic covariates, SLCO1B1 variants accounted for 10.7% of the population variability in clearance. Of that variability, common NS variants accounted for the majority, but rare damaging NS variants constituted 17.8% of SLCO1B1's effects (1.9% of total variation) and had larger effect sizes than common NS variants. Our results show that rare variants are likely to have an important effect on pharmacogenetic phenotypes. PMID:22147369

33 CFR 62.63 - Recommendations.

Code of Federal Regulations, 2012 CFR

2012-07-01

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Clearance detector and method for motion and distance

DOEpatents

Xavier, Patrick G [Albuquerque, NM

2011-08-09

A method for correct and efficient detection of clearances between three-dimensional bodies in computer-based simulations, where one or both of the volumes is subject to translation and/or rotations. The method conservatively determines of the size of such clearances and whether there is a collision between the bodies. Given two bodies, each of which is undergoing separate motions, the method utilizes bounding-volume hierarchy representations for the two bodies and, mappings and inverse mappings for the motions of the two bodies. The method uses the representations, mappings and direction vectors to determine the directionally furthest locations of points on the convex hulls of the volumes virtually swept by the bodies and hence the clearance between the bodies, without having to calculate the convex hulls of the bodies. The method includes clearance detection for bodies comprising convex geometrical primitives and more specific techniques for bodies comprising convex polyhedra.

Turbine blade tip clearance measurement using a skewed dual-beam fiber optic sensor

NASA Astrophysics Data System (ADS)

Ye, De-chao; Duan, Fa-jie; Guo, Hao-tian; Li, Yangzong; Wang, Kai

2012-08-01

Optimization and active control of the tip clearance of turbine blades has been identified as a key to improve fuel efficiency, reduce emission, and increase service life of the engine. However, reliable and real-time tip clearance measurement is difficult due to the adverse environmental conditions that are typically found in a turbine. We describe a dual-beam fiber optic measurement system that can measure the tip timing and tip clearance simultaneously. Because the tip timing information is used to calculate the tip clearance, the method is insensitive to the signal intensity variation caused by fluctuations in environmental conditions such as light source instability, contamination, and blade tip imperfection. The system was calibrated and tested using experimental rotors. The test results indicated a high resolution of 4.5 μm and measurement accuracy of ±20 μm over the rotation speed range of 2000 to 10,000 rpm.

Dual roles for hepatic lectin receptors in the clearance of chilled platelets.

PubMed

Rumjantseva, Viktoria; Grewal, Prabhjit K; Wandall, Hans H; Josefsson, Emma C; Sørensen, Anne Louise; Larson, Göran; Marth, Jamey D; Hartwig, John H; Hoffmeister, Karin M

2009-11-01

Rapid chilling causes glycoprotein-Ib (GPIb) receptors to cluster on blood platelets. Hepatic macrophage beta(2) integrin binding to beta-N-acetylglucosamine (beta-GlcNAc) residues in the clusters leads to rapid clearance of acutely chilled platelets after transfusion. Although capping the beta-GlcNAc moieties by galactosylation prevents clearance of short-term-cooled platelets, this strategy is ineffective after prolonged refrigeration. We report here that prolonged refrigeration increased the density and concentration of exposed galactose residues on platelets such that hepatocytes, through Ashwell-Morell receptor binding, become increasingly involved in platelet removal. Macrophages rapidly removed a large fraction of transfused platelets independent of their storage conditions. With prolonged platelet chilling, hepatocyte-dependent clearance further diminishes platelet recovery and survival after transfusion. Inhibition of chilled platelet clearance by both beta(2) integrin and Ashwell-Morell receptors may afford a potentially simple method for storing platelets in the cold.

Interspecies scaling and prediction of human clearance: comparison of small- and macro-molecule drugs

PubMed Central

Huh, Yeamin; Smith, David E.; Feng, Meihau Rose

2014-01-01

Human clearance prediction for small- and macro-molecule drugs was evaluated and compared using various scaling methods and statistical analysis.Human clearance is generally well predicted using single or multiple species simple allometry for macro- and small-molecule drugs excreted renally.The prediction error is higher for hepatically eliminated small-molecules using single or multiple species simple allometry scaling, and it appears that the prediction error is mainly associated with drugs with low hepatic extraction ratio (Eh). The error in human clearance prediction for hepatically eliminated small-molecules was reduced using scaling methods with a correction of maximum life span (MLP) or brain weight (BRW).Human clearance of both small- and macro-molecule drugs is well predicted using the monkey liver blood flow method. Predictions using liver blood flow from other species did not work as well, especially for the small-molecule drugs. PMID:21892879

Control means for a gas turbine engine

NASA Technical Reports Server (NTRS)

Beitler, R. S.; Sellers, F. J.; Bennett, G. W. (Inventor)

1982-01-01

A means is provided for developing a signal representative of the actual compressor casing temperature, a second signal representative of compressor inlet gas temperature, and a third signal representative of compressor speed. Another means is provided for receiving the gas temperature and compressor speed signals and developing a schedule output signal which is a representative of a reference casing temperature at which a predetermined compressor blade stabilized clearance is provided. A means is also provided for comparing the actual compressor casing temperature signal and the reference casing temperature signal and developing a clearance control system representative of the difference. The clearance control signal is coupled to a control valve which controls a flow of air to the compressor casing to control the clearance between the compressor blades and the compressor casing. The clearance control signal can be modified to accommodate transient characteristics. Other embodiments are disclosed.

Role of genetic variation in docetaxel-induced neutropenia and pharmacokinetics.

PubMed

Nieuweboer, A J M; Smid, M; de Graan, A-J M; Elbouazzaoui, S; de Bruijn, P; Eskens, F A L M; Hamberg, P; Martens, J W M; Sparreboom, A; de Wit, R; van Schaik, R H N; Mathijssen, R H J

2016-11-01

Docetaxel is used for treatment of several solid malignancies. In this study, we aimed for predicting docetaxel clearance and docetaxel-induced neutropenia by developing several genetic models. Therefore, pharmacokinetic data and absolute neutrophil counts (ANCs) of 213 docetaxel-treated cancer patients were collected. Next, patients were genotyped for 1936 single nucleotide polymorphisms (SNPs) in 225 genes using the drug-metabolizing enzymes and transporters platform and thereafter split into two cohorts. The combination of SNPs that best predicted severe neutropenia or low clearance was selected in one cohort and validated in the other. Patients with severe neutropenia had lower docetaxel clearance than patients with ANCs in the normal range (P=0.01). Severe neutropenia was predicted with 70% sensitivity. True low clearance (1 s.d.