Designing the STS-134 Re-Rendezvous: A Preparation for Future Crewed Rendezvous Missions

Science.gov (United States)

Stuit, Timothy D.

2011-01-01

In preparation to provide the capability for the Orion spacecraft, also known as the Multi-Purpose Crew Vehicle (MPCV), to rendezvous with the International Space Station (ISS) and future spacecraft, a new suite of relative navigation sensors are in development and were tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the Orion relative navigation sensors on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle orbiter at the end of the mission. Unlike the rendezvous and docking at the beginning of the mission, the re-rendezvous profile replicates the newly designed Orion coelliptic approach trajectory, something never before attempted with the shuttle orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this rerendezvous to make the flight test successful. Additionally, all of this work had to be integrated with the normal operations of the ISS and shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and rerendezvous trajectory design that would not only prove the design of the relative navigation sensors for the Orion vehicle, but also would serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

Survey of orbital dynamics and control of space rendezvous

Directory of Open Access Journals (Sweden)

Luo Yazhong

2014-02-01

Full Text Available Rendezvous orbital dynamics and control (RODC is a key technology for operating space rendezvous and docking missions. This paper surveys the studies on RODC. Firstly, the basic relative dynamics equation set is introduced and its improved versions are evaluated. Secondly, studies on rendezvous trajectory optimization are commented from three aspects: the linear rendezvous, the nonlinear two-body rendezvous, and the perturbed and constrained rendezvous. Thirdly, studies on relative navigation are briefly reviewed, and then close-range control methods including automated control, manual control, and telecontrol are analyzed. Fourthly, advances in rendezvous trajectory safety and robust analysis are surveyed, and their applications in trajectory optimization are discussed. Finally, conclusions are drawn and prospects of studies on RODC are presented.

STS-134 Re-Rendezvous Design History

Science.gov (United States)

Stuit, Timothy D.

2011-01-01

In preparation to provide the capability for the Orion spacecraft to rendezvous with the International Space Station (ISS), a new suite of relative navigation sensors are in development and will be tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the instruments on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle Orbiter at the end of the mission. Unlike the initial rendezvous and docking, the re-rendezvous profile would replicate the newly designed Orion coelliptic approach trajectory, something never before attempted with the Shuttle Orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this re-rendezvous to make the flight test successful. And all of this work had to be integrated with the normal operations of the ISS and Shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and re-rendezvous trajectory design that will prove not only the design of the relative navigation sensors for the Orion vehicle, but also will serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

Spacecraft rendezvous and docking

DEFF Research Database (Denmark)

Jørgensen, John Leif

1999-01-01

The phenomenons and problems encountered when a rendezvous manoeuvre, and possible docking, of two spacecrafts has to be performed, have been the topic for numerous studies, and, details of a variety of scenarios has been analysed. So far, all solutions that has been brought into realization has...... been based entirely on direct human supervision and control. This paper describes a vision-based system and methodology, that autonomously generates accurate guidance information that may assist a human operator in performing the tasks associated with both the rendezvous and docking navigation...

Guidance and Control of Position and Attitude for Rendezvous and Dock/Berthing with a Noncooperative/Target Spacecraft

Directory of Open Access Journals (Sweden)

Gilberto Arantes

2014-01-01

Full Text Available Noncooperative target spacecrafts are those assets in orbit that cannot convey any information about their states (position, attitude, and velocities or facilitate rendezvous and docking/berthing (RVD/B process. Designing a guidance, navigation, and control (GNC module for the chaser in a RVD/B mission with noncooperative target should be inevitably solved for on-orbit servicing technologies. The proximity operations and the guidance for achieving rendezvous problems are addressed in this paper. The out-of-plane maneuvers of proximity operations are explored with distinct subphases, including a chaser far approach in the target’s orbit to the first hold point and a closer approach to the final berthing location. Accordingly, guidance solutions are chosen for each subphase from the standard Hill based Closhessy-Willtshire (CW solution, elliptical fly-around, and Glideslope algorithms. The control is based on a linear quadratic regulator approach (LQR. At the final berthing location, attitude tracker based on a proportional derivative (PD form is tested to synchronize the chaser and target attitudes. The paper analyzes the performance of both controllers in terms of the tracking ability and the robustness. Finally, it prescribes any restrictions that may be imposed on the guidance during any subphase which can help to improve the controllers tracking ability.

On-Board Rendezvous Targeting for Orion

Science.gov (United States)

Weeks, Michael W.; DSouza, Christopher N.

2010-01-01

The Orion On-board GNC system is among the most complex ever developed for a space mission. It is designed to operate autonomously (independent of the ground). The rendezvous system in particular was designed to operate on the far side of the moon, and in the case of loss-of-communications with the ground. The vehicle GNC system is designed to retarget the rendezvous maneuvers, given a mission plan. As such, all the maneuvers which will be performed by Orion, have been designed and are being incorporated into the flight code.

Rendezvous endoscopic recanalization for complete esophageal obstruction.

Science.gov (United States)

Fusco, Stefano; Kratt, Thomas; Gani, Cihan; Stueker, Dietmar; Zips, Daniel; Malek, Nisar P; Goetz, Martin

2018-03-30

Complete esophageal obstruction after (chemo)radiation for head and neck cancers is rare. However, inability to swallow one's own saliva strongly inflicts upon quality of life. Techniques for endoscopic recanalization in complete obstruction are not well established. We assessed the efficacy and safety of rendezvous recanalization. We performed a retrospective review of all patients who underwent endoscopic recanalization of complete proximal esophageal obstruction after radiotherapy between January 2009 and June 2016. Technical success was defined as an ability to pass an endoscope across the recanalized lumen, clinical success by changes in the dysphagia score. Adverse events were recorded prospectively. 19 patients with complete obstruction (dysphagia IV°), all of whom had failed at least one trial of conventional dilatation, underwent recanalization by endoscopic rendezvous, a combined approach through a gastrostomy and perorally under fluoroscopic control. Conscious sedation was used in all patients. In 18/19 patients (94.7%), recanalization was technically successful. In 14/18 patients (77.8%), the post-intervention dysphagia score changed to ≤ II. Three patients had their PEG removed. Factors negatively associated with success were obstruction length of 50 mm; and tumor recurrence for long-term success. No severe complications were recorded. Rendezvous recanalization for complete esophageal obstruction is a reliable and safe method to re-establish luminal patency. Differences between technical and clinical success rates highlight the importance of additional functional factors associated with dysphagia. Given the lack of therapeutic alternatives, rendezvous recanalization is a valid option to improve dysphagia.

Automatic rendezvous and docking systems functional and performance requirements

Science.gov (United States)

1985-01-01

A generalized mission design scheme which utilizes a standard mission profile for all OMV rendezvous operations, recognizes typical operational constraints, and minimizes propellant penalties due to nodal regression effects was developed. This scheme has been used to demonstrate a unified guidance and navigation maneuver processor (the UMP), which supports all mission phases through station-keeping. The initial demonstration version of the Orbital Rendezvous Mission Planner (ORMP) was provided for evaluation purposes, and program operation was discussed.

Shared control on lunar spacecraft teleoperation rendezvous operations with large time delay

Science.gov (United States)

Ya-kun, Zhang; Hai-yang, Li; Rui-xue, Huang; Jiang-hui, Liu

2017-08-01

Teleoperation could be used in space on-orbit serving missions, such as object deorbits, spacecraft approaches, and automatic rendezvous and docking back-up systems. Teleoperation rendezvous and docking in lunar orbit may encounter bottlenecks for the inherent time delay in the communication link and the limited measurement accuracy of sensors. Moreover, human intervention is unsuitable in view of the partial communication coverage problem. To solve these problems, a shared control strategy for teleoperation rendezvous and docking is detailed. The control authority in lunar orbital maneuvers that involves two spacecraft as rendezvous and docking in the final phase was discussed in this paper. The predictive display model based on the relative dynamic equations is established to overcome the influence of the large time delay in communication link. We discuss and attempt to prove via consistent, ground-based simulations the relative merits of fully autonomous control mode (i.e., onboard computer-based), fully manual control (i.e., human-driven at the ground station) and shared control mode. The simulation experiments were conducted on the nine-degrees-of-freedom teleoperation rendezvous and docking simulation platform. Simulation results indicated that the shared control methods can overcome the influence of time delay effects. In addition, the docking success probability of shared control method was enhanced compared with automatic and manual modes.

A manned maneuvering unit proximity operations planning and flight guidance display and control system

Science.gov (United States)

Gershzohn, Gary R.; Sirko, Robert J.; Zimmerman, K.; Jones, A. D.

1990-01-01

This task concerns the design, development, testing, and evaluation of a new proximity operations planning and flight guidance display and control system for manned space operations. A forecast, derivative manned maneuvering unit (MMU) was identified as a candidate for the application of a color, highway-in-the-sky display format for the presentation of flight guidance information. A silicon graphics 4D/20-based simulation is being developed to design and test display formats and operations concepts. The simulation includes the following: (1) real-time color graphics generation to provide realistic, dynamic flight guidance displays and control characteristics; (2) real-time graphics generation of spacecraft trajectories; (3) MMU flight dynamics and control characteristics; (4) control algorithms for rotational and translational hand controllers; (5) orbital mechanics effects for rendezvous and chase spacecraft; (6) inclusion of appropriate navigation aids; and (7) measurement of subject performance. The flight planning system under development provides for: (1) selection of appropriate operational modes, including minimum cost, optimum cost, minimum time, and specified ETA; (2) automatic calculation of rendezvous trajectories, en route times, and fuel requirements; (3) and provisions for manual override. Man/machine function allocations in planning and en route flight segments are being evaluated. Planning and en route data are presented on one screen composed of two windows: (1) a map display presenting a view perpendicular to the orbital plane, depicting flight planning trajectory and time data attitude display presenting attitude and course data for use en route; and (2) an attitude display presenting local vertical-local horizontal attitude data superimposed on a highway-in-the-sky or flight channel representation of the flight planned course. Both display formats are presented while the MMU is en route. In addition to these displays, several original display

Expert system isssues in automated, autonomous space vehicle rendezvous

Science.gov (United States)

Goodwin, Mary Ann; Bochsler, Daniel C.

1987-01-01

The problems involved in automated autonomous rendezvous are briefly reviewed, and the Rendezvous Expert (RENEX) expert system is discussed with reference to its goals, approach used, and knowledge structure and contents. RENEX has been developed to support streamlining operations for the Space Shuttle and Space Station program and to aid definition of mission requirements for the autonomous portions of rendezvous for the Mars Surface Sample Return and Comet Nucleus Sample return unmanned missions. The experience with REMEX to date and recommendations for further development are presented.

Impact of the Intracoronary Rendezvous technique on coronary angioplasty for chronic total occlusion.

Science.gov (United States)

Nihei, Taro; Yamamoto, Yoshito; Kudo, Shun; Hanawa, Kenichiro; Hasebe, Yuhi; Takagi, Yusuke; Minatoya, Yutaka; Sugi, Masafumi; Shimokawa, Hiroaki

2017-10-01

The Rendezvous technique, which requires bidirectional wiring, is one of the useful methods for improving the success rate of recanalization for chronic total occlusion (CTO) in the field of peripheral intervention. Recently, advanced new devices for percutaneous coronary intervention have enabled us to perform the Rendezvous technique for peripheral as well as for coronary CTO lesions. We used the Intracoronary Rendezvous technique to perform angioplasty for coronary CTO. "Intracoronary Rendezvous" means that Rendezvous was achieved within the CTO lesion. From March 2009 to November 2015, 189 patients underwent CTO angioplasty at our institute, and we treated 10 patients with the Intracoronary Rendezvous technique. This technique involves crossing the Gaia series guidewire to the contralateral Corsair microcatheter located inside the plaque of CTO lesions. The majority of the CTO sites examined were in the proximal RCA (60 %). Lesion length of the occlusion was relatively long (64.4 ± 12.2 mm). Using the biplane imaging system, we were able to control the Gaia guidewires in a specific direction. Furthermore, if the antegrade and retrograde wires can be advanced into contiguous space inside the CTO lesion, we intentionally entered either wire into the contralateral Corsair microcatheter, followed by successful CTO crossing. CTO recanalization was completed for all patients without controlled antegrade retrograde subintimal tracking (CART) or reverse CART. No major complications occurred during hospitalization. These results indicate that the Rendezvous technique, assisted by new devices and a biplane imaging system, represents one of the primary options to achieve successful coronary CTO recanalization.

14 CFR 1214.111 - Rendezvous services.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Rendezvous services. 1214.111 Section 1214....111 Rendezvous services. (a) A rendezvous mission involves the rendezvous of the Space Shuttle orbiter... conditions for both dedicated and shared flight rendezvous services will be negotiated on a case-by-case...

Design of relative trajectories for in orbit proximity operations

Science.gov (United States)

Opromolla, Roberto; Fasano, Giancarmine; Rufino, Giancarlo; Grassi, Michele

2018-04-01

This paper presents an innovative approach to design relative trajectories suitable for close-proximity operations in orbit, by assigning high-level constraints regarding their stability, shape and orientation. Specifically, this work is relevant to space mission scenarios, e.g. formation flying, on-orbit servicing, and active debris removal, which involve either the presence of two spacecraft carrying out coordinated maneuvers, or a servicing/recovery spacecraft (chaser) performing monitoring, rendezvous and docking with respect to another space object (target). In the above-mentioned scenarios, an important aspect is the capability of reducing collision risks and of providing robust and accurate relative navigation solutions. To this aim, the proposed approach exploits a relative motion model relevant to two-satellite formations, and developed in mean orbit parameters, which takes the perturbation effect due to secular Earth oblateness, as well as the motion of the target along a small-eccentricity orbit, into account. This model is used to design trajectories which ensure safe relative motion, to minimize collision risks and relax control requirements, providing at the same time favorable conditions, in terms of target-chaser relative observation geometry for pose determination and relative navigation with passive or active electro-optical sensors on board the chaser. Specifically, three design strategies are proposed in the context of a space target monitoring scenario, considering as design cases both operational spacecraft and debris, characterized by highly variable shape, size and absolute rotational dynamics. The effectiveness of the proposed design approach in providing favorable observation conditions for target-chaser relative pose estimation is demonstrated within a simulation environment which reproduces the designed target-chaser relative trajectory, the operation of an active LIDAR installed on board the chaser, and pose estimation algorithms.

Q-Learning and p-persistent CSMA based rendezvous protocol for cognitive radio networks operating with shared spectrum activity

Science.gov (United States)

Watson, Clifton L.; Biswas, Subir

2014-06-01

With an increasing demand for spectrum, dynamic spectrum access (DSA) has been proposed as viable means for providing the flexibility and greater access to spectrum necessary to meet this demand. Within the DSA concept, unlicensed secondary users temporarily "borrow" or access licensed spectrum, while respecting the licensed primary user's rights to that spectrum. As key enablers for DSA, cognitive radios (CRs) are based on software-defined radios which allow them to sense, learn, and adapt to the spectrum environment. These radios can operate independently and rapidly switch channels. Thus, the initial setup and maintenance of cognitive radio networks are dependent upon the ability of CR nodes to find each other, in a process known as rendezvous, and create a link on a common channel for the exchange of data and control information. In this paper, we propose a novel rendezvous protocol, known as QLP, which is based on Q-learning and the p-persistent CSMA protocol. With the QLP protocol, CR nodes learn which channels are best for rendezvous and thus adapt their behavior to visit those channels more frequently. We demonstrate through simulation that the QLP protocol provides a rendevous capability for DSA environments with different dynamics of PU activity, while attempting to achieve the following performance goals: (1) minimize the average time-to-rendezvous, (2) maximize system throughput, (3) minimize primary user interference, and (4) minimize collisions among CR nodes.

Proximity operations concept design study, task 6

Science.gov (United States)

Williams, A. N.

1990-01-01

The feasibility of using optical technology to perform the mission of the proximity operations communications subsystem on Space Station Freedom was determined. Proximity operations mission requirements are determined and the relationship to the overall operational environment of the space station is defined. From this information, the design requirements of the communication subsystem are derived. Based on these requirements, a preliminary design is developed and the feasibility of implementation determined. To support the Orbital Maneuvering Vehicle and National Space Transportation System, the optical system development is straightforward. The requirements on extra-vehicular activity are such as to allow large fields of uncertainty, thus exacerbating the acquisition problem; however, an approach is given that could mitigate this problem. In general, it is found that such a system could indeed perform the proximity operations mission requirement, with some development required to support extra-vehicular activity.

Comet rendezvous mission design using Solar Electric Propulsion

Science.gov (United States)

Sackett, L. L.; Hastrup, R. C.; Yen, C.-W. L.; Wood, L. J.

1979-01-01

A dual comet (Halley Flyby/Tempel 2 Rendezvous) mission, which is planned to be the first to use the Solar Electric Propulsion System (SEPS), is to be launched in 1985. The purpose of this paper is to describe how the mission design attempts to maximize science return while working within spacecraft and other constraints. Science requirements and desires are outlined and specific instruments are considered. Emphasis is on the strategy for operations in the vicinity of Tempel 2, for which a representative profile is described. The mission is planned to extend about one year past initial rendezvous. Because of the large uncertainty in the comet environment the Tempel 2 operations strategy must be highly adaptive.

Design and Implementation of the Automated Rendezvous Targeting Algorithms for Orion

Science.gov (United States)

DSouza, Christopher; Weeks, Michael

2010-01-01

The Orion vehicle will be designed to perform several rendezvous missions: rendezvous with the ISS in Low Earth Orbit (LEO), rendezvous with the EDS/Altair in LEO, a contingency rendezvous with the ascent stage of the Altair in Low Lunar Orbit (LLO) and a contingency rendezvous in LLO with the ascent and descent stage in the case of an aborted lunar landing. Therefore, it is not difficult to realize that each of these scenarios imposes different operational, timing, and performance constraints on the GNC system. To this end, a suite of on-board guidance and targeting algorithms have been designed to meet the requirement to perform the rendezvous independent of communications with the ground. This capability is particularly relevant for the lunar missions, some of which may occur on the far side of the moon. This paper will describe these algorithms which are designed to be structured and arranged in such a way so as to be flexible and able to safely perform a wide variety of rendezvous trajectories. The goal of the algorithms is not to merely fly one specific type of canned rendezvous profile. Conversely, it was designed from the start to be general enough such that any type of trajectory profile can be flown.(i.e. a coelliptic profile, a stable orbit rendezvous profile, and a expedited LLO rendezvous profile, etc) all using the same rendezvous suite of algorithms. Each of these profiles makes use of maneuver types which have been designed with dual goals of robustness and performance. They are designed to converge quickly under dispersed conditions and they are designed to perform many of the functions performed on the ground today. The targeting algorithms consist of a phasing maneuver (NC), an altitude adjust maneuver (NH), and plane change maneuver (NPC), a coelliptic maneuver (NSR), a Lambert targeted maneuver, and several multiple-burn targeted maneuvers which combine one of more of these algorithms. The derivation and implementation of each of these

A Comparison Between Orion Automated and Space Shuttle Rendezvous Techniques

Science.gov (United States)

Ruiz, Jose O,; Hart, Jeremy

2010-01-01

architecture and contrast it with shuttle rendezvous techniques and circumstances. The shuttle rendezvous profile is timed to take approximately 3 days from orbit insertion to docking at the International Space Station (ISS). This process can be divided into 3 phases: far-field, mid-field and proximity operations. The far-field stage is characterized as the most quiescent phase. The spacecraft is usually too far to navigate using relative sensors and uses the Inertial Measurement Units (IMU s) to numerically solve for its position. The maneuvers are infrequent, roughly twice per day, and are larger than other burns in the profile. The shuttle uses this opportunity to take extensive ground based radar updates and keep high fidelity orbit states on the ground. This state is then periodically uplinked to the shuttle computers. The targeting solutions for burn maneuvers are also computed on the ground and uplinked. During the burn the crew is responsible for setting the shuttle attitude and configuring the propulsion system for ignition. Again this entire process is manually driven by both crew and ground activity. The only automatic processes that occur are associated with the real-time execution of the burn. The Orion automated functionality will seek to relieve the workload of both the crew and ground during this phase

The Rendezvous Technique for Common Bile Duct Stones: A Meta-Analysis.

Science.gov (United States)

Huang, Long; Yu, Qing-sheng; Zhang, Qi; Liu, Ju-da; Wang, Zhen

2015-12-01

This article aimed to clarify the effectiveness and the efficiency of the rendezvous technique for patients with common bile duct stones. Four databases were searched on associations with rendezvous treatment. Six randomized controlled trials were evaluated for their success rate, stone clearance, morbidity, mortality, conversions, hospital stay, operating time, and hospitalization charges. This meta-analysis suggested no significant difference between the rendezvous group and the sequence group in the success rate and the stone clearance, but showed significant differences in the morbidity [odds ratio (OR)=0.54; 95% confidence intervals (CI), 0.30, 0.96], conversions (OR=0.40; 95% CI, 0.16, 0.97), the length of hospital stay (OR=-1.97; 95% CI, -2.29, -1.66), and the operating time (OR=12.95; 95% CI, 7.66, 18.24). The rendezvous technique is as effective as sequential endoscopic management for patients with common bile duct stones in its success rate and stone clearance, but the former is preferred in terms of morbidity, hospital stay, and hospitalization charges.

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory

Science.gov (United States)

Brewster, L.; Johnston, A.; Howard, R.; Mitchell, J.; Cryan, S.

2007-01-01

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-loop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of"pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Lab

Science.gov (United States)

Brewster, Linda L.; Howard, Richard T.; Johnston, A. S.; Carrington, Connie; Mitchell, Jennifer D.; Cryan, Scott P.

2008-01-01

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success ofthe Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-Ioop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of "pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL

75 FR 44794 - Rendezvous International v.

Science.gov (United States)

2010-07-29

... FEDERAL MARITIME COMMISSION [Docket No. 10-07] Rendezvous International v. Chief Cargo Services, Inc., Kaiser Apparel, Inc., Edco Logistics, Inc., Oriental Logistics, Inc., and Razor Enterprise... Federal Maritime Commission (``Commission'') by Rendezvous International (``Rendezvous''), hereinafter...

Operator learning effects in teleoperated rendezvous & docking

Science.gov (United States)

Wilde, M.; Harder, J.; Purschke, R.

Teleoperation of spacecraft proximity operations and docking requires delicate timing and coordination of spacecraft maneuvers. Experience has shown that human operators show large performance fluctuations in these areas, which are a major factor to be addressed in operator training. In order to allow the quantification of the impact of these human fluctuations on control system performance and the human perception of this performance, a learning curve study was conducted with teleoperated final approach and docking scenarios. Over a period of ten experiment days, three test participants were tasked with repeatedly completing a set of three training scenarios. The scenarios were designed to contain different combinations of the major elements of any final approach and docking situation, and to feature an increasing difficulty level. The individual difficulty levels for the three operators furthermore differed in the level of operator support functions available in their human-machine interfaces. Operator performance in the test scenarios were evaluated in the fields approach success and precision, docking safety, and approach efficiency by a combination of recorded maneuver data and questionnaires. The results show that operator experience and the associated learning curves increase operator performance substantially, regardless of the support system used. The paper also shows that the fluctuations in operator performance and self-perception are substantial between as well as within experiment days, and must be reckoned with in teleoperation system design and mission planning.

Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP) procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy) for the management of cholelithiasis with choledocholithiasis.

Science.gov (United States)

Sahoo, Manash Ranjan; Kumar, Anil T; Patnaik, Aashish

2014-07-01

The 'Rendezvous' technique consists of laparoscopic cholecystectomy (LC) standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In 'group-A',41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP) and common bile duct (CBD) clearance and second by LC. In 'group-B', 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5%) and in arm-B in 39 cases (93%). In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22%) and severe pancreatitis in five patients (12%) versus none of the patients (0%) in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient's compliance and prevents unnecessary intervention to CBD.

Rendezvous and Docking for Space Exploration

Science.gov (United States)

Machula, M. F.; Crain, T.; Sandhoo, G. S.

2005-01-01

To achieve the exploration goals, new approaches to exploration are being envisioned that include robotic networks, modular systems, pre-positioned propellants and in-space assembly in Earth orbit, Lunar orbit and other locations around the cosmos. A fundamental requirement for rendezvous and docking to accomplish in-space assembly exists in each of these locations. While existing systems and technologies can accomplish rendezvous and docking in low earth orbit, and rendezvous and docking with crewed systems has been successfully accomplished in low lunar orbit, our capability must extend toward autonomous rendezvous and docking. To meet the needs of the exploration vision in-space assembly requiring both crewed and uncrewed vehicles will be an integral part of the exploration architecture. This paper focuses on the intelligent application of autonomous rendezvous and docking technologies to meet the needs of that architecture. It also describes key technology investments that will increase the exploration program's ability to ensure mission success, regardless of whether the rendezvous are fully automated or have humans in the loop.

Comparative study of rendezvous techniques in post-liver transplant biliary stricture.

Science.gov (United States)

Chang, Jae Hyuck; Lee, In Seok; Chun, Ho Jong; Choi, Jong Young; Yoon, Seung Kyoo; Kim, Dong Goo; You, Young Kyoung; Choi, Myung-Gyu; Han, Sok Won

2012-11-07

To investigate the usefulness of a new rendezvous technique for placing stents using the Kumpe (KMP) catheter in angulated or twisted biliary strictures. The rendezvous technique was performed in patients with a biliary stricture after living donor liver transplantation (LDLT) who required the exchange of percutaneous transhepatic biliary drainage catheters for inside stents. The rendezvous technique was performed using a guidewire in 19 patients (guidewire group) and using a KMP catheter in another 19 (KMP catheter group). We compared the two groups retrospectively. The baseline characteristics did not differ between the groups. The success rate for placing inside stents was 100% in both groups. A KMP catheter was easier to manipulate than a guidewire. The mean procedure time in the KMP catheter group (1012 s, range: 301-2006 s) was shorter than that in the guidewire group (2037 s, range: 251-6758 s, P = 0.022). The cumulative probabilities corresponding to the procedure time of the two groups were significantly different (P = 0.008). The factors related to procedure time were the rendezvous technique method, the number of inside stents, the operator, and balloon dilation of the stricture (P rendezvous technique method was the only significant factor related to procedure time (P = 0.010). The procedural complications observed included one case of mild acute pancreatitis and one case of acute cholangitis in the guidewire group, and two cases of mild acute pancreatitis in the KMP catheter group. The rendezvous technique involving use of the KMP catheter was a fast and safe method for placing inside stents in patients with LDLT biliary stricture that represents a viable alternative to the guidewire rendezvous technique.

Test Results for the Automated Rendezvous and Capture System

Science.gov (United States)

Cruzen, Craig; Dabney, Richard; Lomas, James

1999-01-01

The Automated Rendezvous and Capture (AR&C) system was designed and tested at NASA's Marshall Space Flight Center (MSFC) to demonstrate technologies and mission strategies for automated rendezvous and docking of spacecraft in Earth orbit, The system incorporates some of the latest innovations in Global Positioning, System space navigation, laser sensor technologies and automated mission sequencing algorithms. The system's initial design and integration was completed in 1998 and has undergone testing at MSFC. This paper describes the major components of the AR&C system and presents results from the official system tests performed in MSFC's Flight Robotics Laboratory with digital simulations and hardware in the loop tests. The results show that the AR&C system can safely and reliably perform automated rendezvous and docking missions in the absence of system failures with 100 percent success. When system failures are included, the system uses its automated collision avoidance maneuver logic to recover in a safe manner. The primary objective of the AR&C project is to prove that by designing a safe and robust automated system, mission operations cost can be reduced by decreasing the personnel required for mission design, preflight planning and training required for crewed rendezvous and docking missions.

Short rendezvous missions for advanced Russian human spacecraft

Science.gov (United States)

Murtazin, Rafail F.; Budylov, Sergey G.

2010-10-01

The two-day stay of crew in a limited inhabited volume of the Soyuz-TMA spacecraft till docking to ISS is one of the most stressful parts of space flight. In this paper a number of possible ways to reduce the duration of the free flight phase are considered. The duration is defined by phasing strategy that is necessary for reduction of the phase angle between the chaser and target spacecraft. Some short phasing strategies could be developed. The use of such strategies creates more comfortable flight conditions for crew thanks to short duration and additionally it allows saving spacecraft's life support resources. The transition from the methods of direct spacecraft rendezvous using one orbit phasing (first flights of " Vostok" and " Soyuz" vehicles) to the currently used methods of two-day rendezvous mission can be observed in the history of Soviet manned space program. For an advanced Russian human rated spacecraft the short phasing strategy is recommended, which can be considered as a combination between the direct and two-day rendezvous missions. The following state of the art technologies are assumed available: onboard accurate navigation; onboard computations of phasing maneuvers; launch vehicle with high accuracy injection orbit, etc. Some operational requirements and constraints for the strategies are briefly discussed. In order to provide acceptable phase angles for possible launch dates the experience of the ISS altitude profile control can be used. As examples of the short phasing strategies, the following rendezvous missions are considered: direct ascent, short mission with the phasing during 3-7 orbits depending on the launch date (nominal or backup). For each option statistical modeling of the rendezvous mission is fulfilled, as well as an admissible phase angle range, accuracy of target state vector and addition fuel consumption coming out of emergency is defined. In this paper an estimation of pros and cons of all options is conducted.

Flocking and rendezvous in distributed robotics

CERN Document Server

Francis, Bruce A

2016-01-01

This brief describes the coordinated control of groups of robots using only sensory input – and no direct external commands. Furthermore, each robot employs the same local strategy, i.e., there are no leaders, and the text also deals with decentralized control, allowing for cases in which no single robot can sense all the others. One can get intuition for the problem from the natural world, for example, flocking birds. How do they achieve and maintain their flying formation? Recognizing their importance as the most basic coordination tasks for mobile robot networks, the brief details flocking and rendezvous. They are shown to be physical illustrations of emergent behaviors with global consensus arising from local interactions. The authors extend the consideration of these fundamental ideas to describe their operation in flying robots and prompt readers to pursue further research in the field.  Flocking and Rendezvous in Distributed Robotics will provide graduate students a firm grounding in the subject, w...

Early laparoendoscopic rendezvous for acute biliary pancreatitis: preliminary results.

Science.gov (United States)

Borzellino, G; Lombardo, F; Minicozzi, A M; Donataccio, M; Cordiano, C

2010-02-01

Early restored patency of the papilla has been hypothesized to reduce complications and mortality of acute biliary pancreatitis. The aim of this study was to evaluate the role of urgent laparoscopic cholecystectomy with intraoperative cholangiography and rendezvous when necessary in acute biliary pancreatitis natural history. Patients observed in the early stage of an acute biliary pancreatitis were included in the study. Operative risk assessment based on American Society of Anesthesiologists (ASA) score allowed the performance of urgent laparoscopic cholecystectomy within 72 h from onset of symptoms in 55 patients and a delayed intervention during the same admission in 21 patients. Intraoperative cholangiography was performed in all cases, and clearance of common bile duct was performed by flushing when possible, or rendezvous when necessary. Evolution of pancreatitis was evaluated with clinical and radiological monitoring. Urgent laparoscopic cholecystectomy was performed in all cases without conversion. At intraoperative cholangiography common bile duct was free in 25 patients, a papillary spasm was observed in 9, and common bile duct stones in 21 patients. Patency of the papilla was restored by flushing in 13 patients, while a rendezvous was necessary in 17 patients. The rate of organ failure and pancreatic necrosis was 1.8%, overall mortality was 1.8%, and overall morbidity 21.8%. No infectious complications of peripancreatic collections were observed. Urgent laparoscopic cholecystectomy with selective intraoperative rendezvous may be considered as a treatment option in the early stage of acute biliary pancreatitis.

Two-phase framework for optimal multi-target Lambert rendezvous

OpenAIRE

Bang, Jun; Ahn, Jaemyung

2017-01-01

This paper proposes a two-phase framework to solve an optimal multi-target Lambert rendezvous problem. The first phase solves a series of single-target rendezvous problems for all departure-arrival object pairs to generate the elementary solutions, which provides candidate rendezvous trajectories (elementary solutions). The second phase formulates a variant of traveling salesman problem (TSP) using the elementary solutions prepared in the first phase and determines the best rendezvous sequenc...

Comprehensive asynchronous symmetric rendezvous algorithm in ...

Indian Academy of Sciences (India)

Meenu Chawla

2017-11-10

Nov 10, 2017 ... Simulation results affirm that CASR algorithm performs better in terms of average time-to-rendezvous as compared ... process; neighbour discovery; symmetric rendezvous algorithm. 1. .... dezvous in finite time under the symmetric model. The CH ..... CASR algorithm in Matlab 7.11 and performed several.

Rendezvous effects in the diffusion process on bipartite metapopulation networks.

Science.gov (United States)

Cao, Lang; Li, Xun; Wang, Bing; Aihara, Kazuyuki

2011-10-01

Epidemic outbreaks have been shown to be closely related to the rendezvous-induced transmission of infection, which is caused by casual contact with infected individuals in public gatherings. To investigate rendezvous effects in the spread of infectious diseases, we propose an epidemic model on metapopulation networks bipartite-divided into two sets of location and rendezvous nodes. At a given transition rate γ(kk')(p), each individual transfers from location k to rendezvous p (where rendezvous-induced disease incidence occurs) and thereafter moves to location k'. We find that the eigenstructure of a transition-rate-dependent matrix determines the epidemic threshold condition. Both analytical and numerical results show that rendezvous-induced transmission accelerates the progress of infectious diseases, implying the significance of outbreak control measures including prevention of public gatherings or decentralization of a large-scale rendezvous into downsized ones.

Electro-optical rendezvous and docking sensors

Science.gov (United States)

Tubbs, David J.; Kesler, Lynn O.; Sirko, Robert J.

1991-01-01

Electro-optical sensors provide unique and critical functionality for space missions requiring rendezvous, docking, and berthing. McDonnell Douglas is developing a complete rendezvous and docking system for both manned and unmanned missions. This paper examines our sensor development and the systems and missions which benefit from rendezvous and docking sensors. Simulation results quantifying system performance improvements in key areas are given, with associated sensor performance requirements. A brief review of NASA-funded development activities and the current performance of electro-optical sensors for space applications is given. We will also describe current activities at McDonnell Douglas for a fully functional demonstration to address specific NASA mission needs.

PREDICTION BASED CHANNEL-HOPPING ALGORITHM FOR RENDEZVOUS IN COGNITIVE RADIO NETWORKS

Directory of Open Access Journals (Sweden)

Dhananjay Kumar

2012-12-01

Full Text Available Most common works for rendezvous in cognitive radio networks deal only with two user scenarios involving two secondary users and variable primary users and aim at reducing the time-to-rendezvous. A common control channel for the establishment of communication is not considered and hence the work comes under the category of ‘Blind Rendezvous’. Our work deal with multi-user scenario and provides a methodology for the users to find each other in the very first time slot spent for rendezvous or otherwise called the firstattempt- rendezvous. The secondary users make use of the history of past communications to enable them to predict the frequency channel that the user expects the rendezvous user to be. Our approach prevents greedy decision making between the users involved by the use of a cut-off time period for attempting rendezvous. Simulation results show that the time-to-rendezvous (TTR is greatly reduced upon comparison with other popular rendezvous algorithms.

Hyperbolic Rendezvous at Mars: Risk Assessments and Mitigation Strategies

Science.gov (United States)

Jedrey, Ricky; Landau, Damon; Whitley, Ryan

2015-01-01

Given the current interest in the use of flyby trajectories for human Mars exploration, a key requirement is the capability to execute hyperbolic rendezvous. Hyperbolic rendezvous is used to transport crew from a Mars centered orbit, to a transiting Earth bound habitat that does a flyby. Representative cases are taken from future potential missions of this type, and a thorough sensitivity analysis of the hyperbolic rendezvous phase is performed. This includes early engine cutoff, missed burn times, and burn misalignment. A finite burn engine model is applied that assumes the hyperbolic rendezvous phase is done with at least two burns.

Methodology for Developing a Probabilistic Risk Assessment Model of Spacecraft Rendezvous and Dockings

Science.gov (United States)

Farnham, Steven J., II; Garza, Joel, Jr.; Castillo, Theresa M.; Lutomski, Michael

2011-01-01

In 2007 NASA was preparing to send two new visiting vehicles carrying logistics and propellant to the International Space Station (ISS). These new vehicles were the European Space Agency s (ESA) Automated Transfer Vehicle (ATV), the Jules Verne, and the Japanese Aerospace and Explorations Agency s (JAXA) H-II Transfer Vehicle (HTV). The ISS Program wanted to quantify the increased risk to the ISS from these visiting vehicles. At the time, only the Shuttle, the Soyuz, and the Progress vehicles rendezvoused and docked to the ISS. The increased risk to the ISS was from an increase in vehicle traffic, thereby, increasing the potential catastrophic collision during the rendezvous and the docking or berthing of the spacecraft to the ISS. A universal method of evaluating the risk of rendezvous and docking or berthing was created by the ISS s Risk Team to accommodate the increasing number of rendezvous and docking or berthing operations due to the increasing number of different spacecraft, as well as the future arrival of commercial spacecraft. Before the first docking attempt of ESA's ATV and JAXA's HTV to the ISS, a probabilistic risk model was developed to quantitatively calculate the risk of collision of each spacecraft with the ISS. The 5 rendezvous and docking risk models (Soyuz, Progress, Shuttle, ATV, and HTV) have been used to build and refine the modeling methodology for rendezvous and docking of spacecrafts. This risk modeling methodology will be NASA s basis for evaluating the addition of future ISS visiting spacecrafts hazards, including SpaceX s Dragon, Orbital Science s Cygnus, and NASA s own Orion spacecraft. This paper will describe the methodology used for developing a visiting vehicle risk model.

Quorum system and random based asynchronous rendezvous protocol for cognitive radio ad hoc networks

Directory of Open Access Journals (Sweden)

Sylwia Romaszko

2013-12-01

Full Text Available This paper proposes a rendezvous protocol for cognitive radio ad hoc networks, RAC2E-gQS, which utilizes (1 the asynchronous and randomness properties of the RAC2E protocol, and (2 channel mapping protocol, based on a grid Quorum System (gQS, and taking into account channel heterogeneity and asymmetric channel views. We show that the combination of the RAC2E protocol with the grid-quorum based channel mapping can yield a powerful RAC2E-gQS rendezvous protocol for asynchronous operation in a distributed environment assuring a rapid rendezvous between the cognitive radio nodes having available both symmetric and asymmetric channel views. We also propose an enhancement of the protocol, which uses a torus QS for a slot allocation, dealing with the worst case scenario, a large number of channels with opposite ranking lists.

Trajectory control with continuous thrust applied to a rendezvous maneuver

International Nuclear Information System (INIS)

Santos, W G; Rocco, E M

2013-01-01

A rendezvous mission can be divided into the following phases: launch, phasing, far range rendezvous, close range rendezvous and mating (docking or berthing). This paper aims to present a close range rendezvous with closed loop controlled straight line trajectory. The approaching is executed on V-bar axis. A PID controller and continuous thrust are used to eliminate the residual errors in the trajectory. A comparative study about the linear and nonlinear dynamics is performed and the results showed that the linear equations become inaccurate insofar as the chaser moves away from the target

The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer

International Nuclear Information System (INIS)

Slattery, S. R.; Wilson, P. P. H.; Pawlowski, R. P.

2013-01-01

The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)

The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer

Energy Technology Data Exchange (ETDEWEB)

Slattery, S. R.; Wilson, P. P. H. [Department of Engineering Physics, University of Wisconsin - Madison, 1500 Engineering Dr., Madison, WI 53706 (United States); Pawlowski, R. P. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

2013-07-01

The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)

An autonomous rendezvous and docking system using cruise missile technologies

Science.gov (United States)

Jones, Ruel Edwin

1991-01-01

In November 1990 the Autonomous Rendezvous & Docking (AR&D) system was first demonstrated for members of NASA's Strategic Avionics Technology Working Group. This simulation utilized prototype hardware from the Cruise Missile and Advanced Centaur Avionics systems. The object was to show that all the accuracy, reliability and operational requirements established for a space craft to dock with Space Station Freedom could be met by the proposed system. The rapid prototyping capabilities of the Advanced Avionics Systems Development Laboratory were used to evaluate the proposed system in a real time, hardware in the loop simulation of the rendezvous and docking reference mission. The simulation permits manual, supervised automatic and fully autonomous operations to be evaluated. It is also being upgraded to be able to test an Autonomous Approach and Landing (AA&L) system. The AA&L and AR&D systems are very similar. Both use inertial guidance and control systems supplemented by GPS. Both use an Image Processing System (IPS), for target recognition and tracking. The IPS includes a general purpose multiprocessor computer and a selected suite of sensors that will provide the required relative position and orientation data. Graphic displays can also be generated by the computer, providing the astronaut / operator with real-time guidance and navigation data with enhanced video or sensor imagery.

The Modular Clock Algorithm for Blind Rendezvous

Science.gov (United States)

2009-03-26

and Computer Engineering Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training...capabilities in spectrum management and particularly in harvesting unused portions of pre-allocated band- width under DSA. The term “cognitive radio” was...of rendezvous and our role as the waiter . However, if the “child” refuses to move from non-common spectrum, rendezvous cannot occur. Bluetooth

Combined antegrade and retrograde ureteral stenting: the rendezvous technique

International Nuclear Information System (INIS)

Macri, A.; Magno, C.; Certo, A.; Basile, A.; Scuderi, G.; Crescenti, F.; Famulari, C.

2005-01-01

Ureteral stenting is a routine procedure in endourology. To increase the success rate in difficult cases, it may be helpful to use the rendezvous technique, a combined antegrade and retrograde approach. We performed 16 urological rendezvous in 11 patients with ureteral strictures or urologic lesions. The combined approach was successful in all patients, without morbidity or mortality. In our experience the rendezvous technique increased the success rate of antegrade ureteral stenting from 78.6 to 88.09% (p>0.05). This procedure is a valid option in case of failure of conventional ureteral stenting

Robust Parametric Control of Spacecraft Rendezvous

Directory of Open Access Journals (Sweden)

Dake Gu

2014-01-01

Full Text Available This paper proposes a method to design the robust parametric control for autonomous rendezvous of spacecrafts with the inertial information with uncertainty. We consider model uncertainty of traditional C-W equation to formulate the dynamic model of the relative motion. Based on eigenstructure assignment and model reference theory, a concise control law for spacecraft rendezvous is proposed which could be fixed through solving an optimization problem. The cost function considers the stabilization of the system and other performances. Simulation results illustrate the robustness and effectiveness of the proposed control.

Randomised study on single stage laparo-endoscopic rendezvous (intra-operative ERCP procedure versus two stage approach (Pre-operative ERCP followed by laparoscopic cholecystectomy for the management of cholelithiasis with choledocholithiasis

Directory of Open Access Journals (Sweden)

Manash Ranjan Sahoo

2014-01-01

Full Text Available Introduction : The ′Rendezvous′ technique consists of laparoscopic cholecystectomy (LC standards with intra-operative cholangiography followed by endoscopic sphincterotomy. The sphincterotome is driven across the papilla through a guidewire inserted by the transcystic route. In this study, we intended to compare the two methods in a prospective randomised trial. Materials And Methods: From 2005 to 2012, we enrolled 83 patients with a diagnosis of cholecysto-choledocolithiasis. They were randomised into two groups. In ′group-A′,41 patients were treated with two stages management, first by pre-operative endoscopic retrograde cholangiopancreatography (ERCP and common bile duct (CBD clearance and second by LC. In ′group-B′, 42 patients were treated with LC and intra-operative cholangiography; and when diagnosis of choledocholithiasis was confirmed, patients had undergone one stage management of by Laparo-endoscopic Rendezvous technique. Results: In arm-A and arm-B groups, complete CBD clearance was achieved in 29 and 38 patients, respectively. Failure of the treatment in arm-A was 29% and in arm-B was 9.5%. In arm-A, selective CBD cannulation was achieved in 33 cases (80.5% and in arm-B in 39 cases (93%. In arm-Agroup, post-ERCP hyperamylasia was presented in nine patients (22% and severe pancreatitis in five patients (12% versus none of the patients (0% in arm-B group, respectively. Mean post-operative hospital stay in arm-A and arm-B groups are 10.9 and 6.8 days, respectively. Conclusion: One stage laparo-endoscopic rendezvous approach increases selective cannulation of CBD, reduces post-ERCP pancreatitis, reduces days of hospital stay, increases patient′s compliance and prevents unnecessary intervention to CBD.

Operator-assisted planning and execution of proximity operations subject to operational constraints

Science.gov (United States)

Grunwald, Arthur J.; Ellis, Stephen R.

1991-01-01

Future multi-vehicle operations will involve multiple scenarios that will require a planning tool for the rapid, interactive creation of fuel-efficient trajectories. The planning process must deal with higher-order, non-linear processes involving dynamics that are often counter-intuitive. The optimization of resulting trajectories can be difficult to envision. An interaction proximity operations planning system is being developed to provide the operator with easily interpreted visual feedback of trajectories and constraints. This system is hosted on an IRIS 4D graphics platform and utilizes the Clohessy-Wiltshire equations. An inverse dynamics algorithm is used to remove non-linearities while the trajectory maneuvers are decoupled and separated in a geometric spreadsheet. The operator has direct control of the position and time of trajectory waypoints to achieve the desired end conditions. Graphics provide the operator with visualization of satisfying operational constraints such as structural clearance, plume impingement, approach velocity limits, and arrival or departure corridors. Primer vector theory is combined with graphical presentation to improve operator understanding of suggested automated system solutions and to allow the operator to review, edit, or provide corrective action to the trajectory plan.

Endo-laparoscopic rendezvous approach for pericardia with gastric posterior wall of gastrointestinal stromal tumor: analysis of 52 consecutive cases.

Science.gov (United States)

Ding, Po; Zhao, Yongjie

2014-12-01

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tract and most frequently developed in the stomach, and surgical therapy is limited on removal of the tumor lesion. The aim of this study was to investigate the clinical values of endo-laparoscopic rendezvous approach for pericardial GISTs within gastric posterior wall. Surgical outcome and clinical data of 52 patients with pericardial GISTs within gastric posterior wall treated at Tianjin Peoples' Hospital from January 2004 to October 2013 were analyzed. Endo-laparoscopic rendezvous approach was used as an operative procedure for tumor resection ranged from 10 to 50 mm. Endoscopic ultrasound, computed tomography and microscopic findings all certified the gastric spindle type GIST locating in the submucosa to muscle proper. Endo-laparoscopic rendezvous approach was attempted in 52 patients (male/female: 31/21) with median age of 51 years (25-71 years). The median operating time was 80 min (range: 40-120 min) and median intra-operative blood loss was 26 ml (range: 10-50 ml). The median hospital stay was 5 days (range: 4-6 days), while the median tumor size was 25 mm (range: 7-50 mm). All operative margins were clear. There were no recurrences or metastases of all patients in a median follow-up of 24 months (range: 6-36 months). Endo-laparoscopic rendezvous approach is considered to represent the next revolution in surgery. The new technique is reliable and effective in clinical application, due to the advantages of accurate and quick localization for pericardial GIST within gastric posterior wall.

Multi-Agent Rendezvousing with a Finite Set of Candidate Rendezvous Points

NARCIS (Netherlands)

Fang, J.; Morse, A. S.; Cao, M.

2008-01-01

The discrete multi-agent rendezvous problem we consider in this paper is concerned with a specified set of points in the plane, called “dwell-points,” and a set of mobile autonomous agents with limited sensing range. Each agent is initially positioned at some dwell-point, and is able to determine

Rendezvous and docking tracker

Science.gov (United States)

Ray, Art J.; Ross, Susan E.; Deming, Douglas R.

1986-01-01

A conceptual solid-state rendezvous and docking tracker (RDT) has been devised for generating range and attitude data for a docking vehicle relative to a target vehicle. Emphasis is placed on the approach of the Orbiter to a link with the Space Station. Three laser illuminators ring the optical axis of the lens a directed toward retroreflectors on the target vehicle. Each retroreflector is equipped with a bandpass filter for a designated illumination frequency. Data are collected sequentially over a 20 deg field of view as the range closes to 100-1000 m. A fourth ranging retroreflector 0.3 m from center is employed during close-in maneuvers. The system provides tracking data on motions with 6 deg of freedom, and furnishes 500 msec updates (to be enhanced to 100 msec) to the operator at a computer console.

The Influence of Spatial Ability and Experience on Spacecraft Rendezvous and Docking Operation Performance

Directory of Open Access Journals (Sweden)

Xiaoping eDu

2015-07-01

Full Text Available Manual rendezvous and docking (manual RVD is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed.

EUS-guided biliary rendezvous using a short hydrophilic guidewire.

Science.gov (United States)

Dhir, Vinay; Kwek, Boon Eu Andrew; Bhandari, Suryaprakash; Bapat, Mukta; Maydeo, Amit

2011-10-01

BACKGROUND AND STUDY AIMS: EUS-guided rendezvous technique for biliary access requires expert manipulation of the guidewire across the downstream stricture or papilla. Published literature reports usage of the long-wire system to prevent loss of wire during scope exchange. We studied the efficacy of using a short hydrophilic guidewire in EUS-guided rendezvous. PATIENTS AND METHODS: This is a retrospective study conducted in a tertiary care referral centre. 15 patients underwent EUS-guided biliary rendezvous with short wire. EUS-guided transduodenal/transgastric puncture of the biliary system was performed, followed by anterograde placement of a hydrophilic short-wire (260 cm) across the downstream stricture and/or papilla. Retrograde access was then achieved by retrieving the trans-papillary wire, followed by standard ERCP intervention. Main outcome measurements were rates of procedural success and complications. RESULTS: EUS-guided biliary rendezvous was successful in 14 patients (93.3%). Failure was seen in one patient due to a tight malignant biliary stricture. One patient had peri-choledochal bile tracking which did not require any specific treatment. CONCLUSIONS: Short-wire system in EUS-guided biliary rendezvous is highly effective and safe. It is a useful salvage procedure for biliary cannulation in patients with accessible papilla.

Treatment for retained [corrected] common bile duct stones during laparoscopic cholecystectomy: the rendezvous technique.

Science.gov (United States)

Borzellino, Giuseppe; Rodella, Luca; Saladino, Edoardo; Catalano, Filippo; Politi, Leonardo; Minicozzi, Annamaria; Cordiano, Claudio

2010-12-01

To determine the feasibility and efficacy of the laparoscopic intraoperative rendezvous technique for common bile duct stones (CBDS). Case series. Verona University Hospital, Verona, Italy. A total of 110 patients were enrolled in the study; 47 had biliary colic; 39, acute cholecystitis; 19, acute biliary pancreatitis; and 5, acute biliary pancreatitis with associated acute cholecystitis. In all patients, CBDS diagnosis was reached by intraoperative cholangiography. Intraoperative endoscopy with rendezvous performed during laparascopic cholecystectomy for confirmed CBDS; for such a procedure, a transcystic guide wire was positioned into the duodenum. Intraoperative endoscopy with rendezvous was performed for retrieved CBDS during a laparoscopic cholecystectomy. Laparoscopic rendezvous feasibility, morbidity, postprocedure pancreatitis, and mortality. The laparoscopic rendezvous proved to be feasible in 95.5% (105 of 110 patients). The rendezvous failed in 3 cases of successfully performed laparoscopic cholecystectomy, and a conversion of the laparoscopy was needed in 2 cases of successful rendezvous. Two major complications and 2 cases of bleeding were registered after sphincterotomy was successfully performed with rendezvous, and severe acute pancreatitis complicated a traditional sphincterotomy performed after a failed rendezvous. Rendezvous is a feasible option for treatment of CBDS; it allows one to perform only 1 stage of treatment, even in acute cases such as cholecystitis and pancreatitis. Positioning of the guide wire may allow reduced complications secondary to papilla cannulation but not those of the endoscopic sphincterotomy.

Endoscopic retrograde cholangiopancreatography with rendezvous cannulation reduces pancreatic injury.

Science.gov (United States)

Swahn, Fredrik; Regnér, Sara; Enochsson, Lars; Lundell, Lars; Permert, Johan; Nilsson, Magnus; Thorlacius, Henrik; Arnelo, Urban

2013-09-28

To examine whether rendezvous endoscopic retrograde cholangiopancreatography (ERCP) is associated with less pancreatic damage, measured as leakage of proenzymes, than conventional ERCP. Patients (n = 122) with symptomatic gallstone disease, intact papilla and no ongoing inflammation, were prospectively enrolled in this case-control designed study. Eighty-one patients were subjected to laparoscopic cholecystectomy and if intraoperative cholangiography suggested common bile duct stones (CBDS), rendezvous ERCP was performed intraoperatively (n = 40). Patients with a negative cholangiogram constituted the control group (n = 41). Another 41 patients with CBDS, not subjected to surgery, underwent conventional ERCP. Pancreatic proenzymes, procarboxypeptidase B and trypsinogen-2 levels in plasma, were analysed at 0, 4, 8 and 24 h. The proenzymes were determined in-house with a double-antibody enzyme linked immunosorbent assay. Pancreatic amylase was measured by an enzymatic colourimetric modular analyser with the manufacturer's reagents. All samples were blinded at analysis. Post ERCP pancreatitis (PEP) occurred in 3/41 (7%) of the patients cannulated with conventional ERCP and none in the rendezvous group. Increased serum levels indicating pancreatic leakage were significantly higher in the conventional ERCP group compared with the rendezvous ERCP group regarding pancreatic amylase levels in the 4- and 8-h samples (P = 0.0015; P = 0.03), procarboxypeptidase B in the 4- and 8-h samples (P rendezvous cannulation technique compared with patients that underwent cholecystectomy alone (control group). Post procedural concentrations of pancreatic amylase and procarboxypeptidase B were significantly correlated with pancreatic duct cannulation and opacification. Rendezvous ERCP reduces pancreatic enzyme leakage compared with conventional ERCP cannulation technique. Thus, laparo-endoscopic technique can be recommended with the ambition to minimise the risk for post ERCP

Endoskopisk ultralydvejledt rendezvous til intern drænage ved galdevejsobstruktion

DEFF Research Database (Denmark)

Knudsen, Marie Høxbro; Vilmann, Peter; Hassan, Hazem

2015-01-01

Endoscopic ultrasound guided rendezvous for biliary drainage Endoscopic retrograde cholangiography (ERCP) is currently standard treatment for biliary drainage. Endoscopic ultrasound guided rendezvous (EUS-RV) is a novel method to overcome an unsuccessful biliary drainage procedure. Under endoscopic...

Inverse simulation system for evaluating handling qualities during rendezvous and docking

Science.gov (United States)

Zhou, Wanmeng; Wang, Hua; Thomson, Douglas; Tang, Guojin; Zhang, Fan

2017-08-01

The traditional method used for handling qualities assessment of manned space vehicles is too time-consuming to meet the requirements of an increasingly fast design process. In this study, a rendezvous and docking inverse simulation system to assess the handling qualities of spacecraft is proposed using a previously developed model-predictive-control architecture. By considering the fixed discrete force of the thrusters of the system, the inverse model is constructed using the least squares estimation method with a hyper-ellipsoidal restriction, the continuous control outputs of which are subsequently dispersed by pulse width modulation with sensitivity factors introduced. The inputs in every step are deemed constant parameters, and the method could be considered as a general method for solving nominal, redundant, and insufficient inverse problems. The rendezvous and docking inverse simulation is applied to a nine-degrees-of-freedom platform, and a novel handling qualities evaluation scheme is established according to the operation precision and astronauts' workload. Finally, different nominal trajectories are scored by the inverse simulation and an established evaluation scheme. The scores can offer theoretical guidance for astronaut training and more complex operation missions.

Gossip-based solutions for discrete rendezvous in populations of communicating agents.

Science.gov (United States)

Hollander, Christopher D; Wu, Annie S

2014-01-01

The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal) meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm.

Gossip-based solutions for discrete rendezvous in populations of communicating agents.

Directory of Open Access Journals (Sweden)

Christopher D Hollander

Full Text Available The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm.

Model predictive control for spacecraft rendezvous in elliptical orbit

Science.gov (United States)

Li, Peng; Zhu, Zheng H.

2018-05-01

This paper studies the control of spacecraft rendezvous with attitude stable or spinning targets in an elliptical orbit. The linearized Tschauner-Hempel equation is used to describe the motion of spacecraft and the problem is formulated by model predictive control. The control objective is to maximize control accuracy and smoothness simultaneously to avoid unexpected change or overshoot of trajectory for safe rendezvous. It is achieved by minimizing the weighted summations of control errors and increments. The effects of two sets of horizons (control and predictive horizons) in the model predictive control are examined in terms of fuel consumption, rendezvous time and computational effort. The numerical results show the proposed control strategy is effective.

Laparoscopic-endoscopic rendezvous versus preoperative endoscopic sphincterotomy in people undergoing laparoscopic cholecystectomy for stones in the gallbladder and bile duct.

Science.gov (United States)

Vettoretto, Nereo; Arezzo, Alberto; Famiglietti, Federico; Cirocchi, Roberto; Moja, Lorenzo; Morino, Mario

2018-04-11

The management of gallbladder stones (lithiasis) concomitant with bile duct stones is controversial. The more frequent approach is a two-stage procedure, with endoscopic sphincterotomy and stone removal from the bile duct followed by laparoscopic cholecystectomy. The laparoscopic-endoscopic rendezvous combines the two techniques in a single-stage operation. To compare the benefits and harms of endoscopic sphincterotomy and stone removal followed by laparoscopic cholecystectomy (the single-stage rendezvous technique) versus preoperative endoscopic sphincterotomy followed by laparoscopic cholecystectomy (two stages) in people with gallbladder and common bile duct stones. We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, Science Citation Index Expanded Web of Science, and two trials registers (February 2017). We included randomised clinical trials that enrolled people with concomitant gallbladder and common bile duct stones, regardless of clinical status or diagnostic work-up, and compared laparoscopic-endoscopic rendezvous versus preoperative endoscopic sphincterotomy procedures in people undergoing laparoscopic cholecystectomy. We excluded other endoscopic or surgical methods of intraoperative clearance of the bile duct, e.g. non-aided intraoperative endoscopic retrograde cholangiopancreatography or laparoscopic choledocholithotomy (surgical incision of the common bile duct for removal of bile duct stones). We used standard methodological procedures recommended by Cochrane. We included five randomised clinical trials with 517 participants (257 underwent a laparoscopic-endoscopic rendezvous technique versus 260 underwent a sequential approach), which fulfilled our inclusion criteria and provided data for analysis. Trial participants were scheduled for laparoscopic cholecystectomy because of suspected cholecysto-choledocholithiasis. Male/female ratio was 0.7; age of men and women ranged from 21 years to 87

Mars Sample Return - Launch and Detection Strategies for Orbital Rendezvous

Science.gov (United States)

Woolley, Ryan C.; Mattingly, Richard L.; Riedel, Joseph E.; Sturm, Erick J.

2011-01-01

This study sets forth conceptual mission design strategies for the ascent and rendezvous phase of the proposed NASA/ESA joint Mars Sample Return Campaign. The current notional mission architecture calls for the launch of an acquisition/cache rover in 2018, an orbiter with an Earth return vehicle in 2022, and a fetch rover and ascent vehicle in 2024. Strategies are presented to launch the sample into a coplanar orbit with the Orbiter which facilitate robust optical detection, orbit determination, and rendezvous. Repeating ground track orbits exist at 457 and 572 km which provide multiple launch opportunities with similar geometries for detection and rendezvous.

Mars Sample Return: Launch and Detection Strategies for Orbital Rendezvous

Science.gov (United States)

Woolley, Ryan C.; Mattingly, Richard L.; Riedel, Joseph E.; Sturm, Erick J.

2011-01-01

This study sets forth conceptual mission design strategies for the ascent and rendezvous phase of the proposed NASA/ESA joint Mars Sample Return Campaign. The current notional mission architecture calls for the launch of an acquisition/ caching rover in 2018, an Earth return orbiter in 2022, and a fetch rover with ascent vehicle in 2024. Strategies are presented to launch the sample into a nearly coplanar orbit with the Orbiter which would facilitate robust optical detection, orbit determination, and rendezvous. Repeating ground track orbits existat 457 and 572 km which would provide multiple launch opportunities with similar geometries for detection and rendezvous.

Rendezvous missions with minimoons from L1

Science.gov (United States)

Chyba, M.; Haberkorn, T.; Patterson, G.

2014-07-01

We propose to present asteroid capture missions with the so-called minimoons. Minimoons are small asteroids that are temporarily captured objects on orbits in the Earth-Moon system. It has been suggested that, despite their small capture probability, at any time there are one or two meter diameter minimoons, and progressively greater numbers at smaller diameters. The minimoons orbits differ significantly from elliptical orbits which renders a rendezvous mission more challenging, however they offer many advantages for such missions that overcome this fact. First, they are already on geocentric orbits which results in short duration missions with low Delta-v, this translates in cost efficiency and low-risk targets. Second, beside their close proximity to Earth, an advantage is their small size since it provides us with the luxury to retrieve the entire asteroid and not only a sample of material. Accessing the interior structure of a near-Earth satellite in its morphological context is crucial to an in-depth analysis of the structure of the asteroid. Historically, 2006 RH120 is the only minimoon that has been detected but work is ongoing to determine which modifications to current observation facilities is necessary to provide detection algorithm capabilities. In the event that detection is successful, an efficient algorithm to produce a space mission to rendezvous with the detected minimoon is highly desirable to take advantage of this opportunity. This is the main focus of our work. For the design of the mission we propose the following. The spacecraft is first placed in hibernation on a Lissajoux orbit around the liberation point L1 of the Earth-Moon system. We focus on eight-shaped Lissajoux orbits to take advantage of the stability properties of their invariant manifolds for our transfers since the cost to minimize is the spacecraft fuel consumption. Once a minimoon has been detected we must choose a point on its orbit to rendezvous (in position and velocities

Combined Sector and Channel Hopping Schemes for Efficient Rendezvous in Directional Antenna Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

AbdulMajid M. Al-Mqdashi

2017-01-01

Full Text Available Rendezvous is a prerequisite and important process for secondary users (SUs to establish data communications in cognitive radio networks (CRNs. Recently, there has been a proliferation of different channel hopping- (CH- based schemes that can provide rendezvous without relying on any predetermined common control channel. However, the existing CH schemes were designed with omnidirectional antennas which can degrade their rendezvous performance when applied in CRNs that are highly crowded with primary users (PUs. In such networks, the large number of PUs may lead to the inexistence of any common available channel between neighboring SUs which result in a failure of their rendezvous process. In this paper, we consider the utilization of directional antennas in CRNs for tackling the issue. Firstly, we propose two coprimality-based sector hopping (SH schemes that can provide efficient pairwise sector rendezvous in directional antenna CRNs (DIR-CRNs. Then, we propose an efficient CH scheme that can be combined within the SH schemes for providing a simultaneous sector and channel rendezvous. The guaranteed rendezvous of our schemes are proven by deriving the theoretical upper bounds of their rendezvous delay metrics. Furthermore, extensive simulation comparisons with other related rendezvous schemes are conducted to illustrate the significant outperformance of our schemes.

Autonomous rendezvous and capture development infrastructure

Science.gov (United States)

Bryan, Thomas C.; Roe, Fred; Coker, Cindy; Nelson, Pam; Johnson, B.

1991-01-01

In the development of the technology for autonomous rendezvous and docking, key infrastructure capabilities must be used for effective and economical development. This involves facility capabilities, both equipment and personnel, to devise, develop, qualify, and integrate ARD elements and subsystems into flight programs. One effective way of reducing technical risks in developing ARD technology is the use of the ultimate test facility, using a Shuttle-based reusable free-flying testbed to perform a Technology Demonstration Test Flight which can be structured to include a variety of additional sensors, control schemes, and operational approaches. This conceptual testbed and flight demonstration will be used to illustrate how technologies and facilities at MSFC can be used to develop and prove an ARD system.

Clinical utility of an endoscopic ultrasound-guided rendezvous technique via various approach routes.

Science.gov (United States)

Kawakubo, Kazumichi; Isayama, Hiroyuki; Sasahira, Naoki; Nakai, Yousuke; Kogure, Hirofumi; Hamada, Tsuyoshi; Miyabayashi, Koji; Mizuno, Suguru; Sasaki, Takashi; Ito, Yukiko; Yamamoto, Natsuyo; Hirano, Kenji; Tada, Minoru; Koike, Kazuhiko

2013-09-01

The endoscopic ultrasound-guided rendezvous techniques (EUS-rendezvous) provide reliable biliary access after failed endoscopic retrograde cholangiopancreatography (ERCP) cannulation. We evaluated the clinical utility of an EUS-rendezvous technique using various approach routes. Patients undergoing EUS-rendezvous for biliary access after failed bile duct cannulation in ERCP were included. EUS-rendezvous was performed via three approach routes depending on the patient's condition: transgastric, transduodenal in a short endoscopic position, or transduodenal in a long endoscopic position. The main outcomes were the technical success rates. Secondary outcomes were procedure time and complications. Fourteen patients (median age, 77 years) underwent EUS-rendezvous for biliary access resulting from failed biliary cannulation. The reasons for biliary drainage were malignant biliary obstruction in five patients and choledocholithiasis in nine. Transgastric, transduodenal in a short position, and transduodenal in a long position EUS-rendezvous was performed in five, five, and four patients, respectively. Bile duct puncture occurred in the left intrahepatic duct in four patients, right hepatic duct in one, middle common bile duct in four, and lower common bile duct in five. The technical success rate was 100 %. In four patients, the approach route was modified from transduodenal in a short position to transduodenal in a long position or transgastric route. The median procedure time was 81 min. One case each of biliary peritonitis and pancreatitis occurred and were managed conservatively. EUS-rendezvous provided safe and reliable transpapillary bile duct access after failed ERCP cannulation. The selection of the appropriate approach routes, depending on patient condition, is critical.

A modified technique reduced operative time of laparoendoscopic rendezvous endoscopic retrograde cholangiopancreatography combined with laparoscopic cholecystectomy for concomitant gallstone and common bile ductal stone.

Science.gov (United States)

Liu, Wei; Wang, Qunwei; Xiao, Jing; Zhao, Liying; Huang, Jiangsheng; Tan, Zhaohui; Li, Pengfei

2014-01-01

Laparoendoscopic rendezvous (LERV) endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy (LC+ERCP/LERV) are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1) from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2) who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9%) in group 1 and 24 cases (86.2%) in group 2. The mean operative time and time of endoscopic part were 82.6 ± 19.6 min and 26.5 ± 5.99 min in group 1 which were significantly shorter than those in group 2 (118.0 ± 23.1 min and 58.7 ± 13.3 min, resp.). There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique.

Proximal tibiofibular joint: Rendezvous with a forgotten articulation

Directory of Open Access Journals (Sweden)

Amitav Sarma

2015-01-01

Full Text Available The proximal tibiofibular joint (PTFJ is a plane type synovial joint. The primary function of the PTFJ is dissipation of torsional stresses applied at the ankle and the lateral tibial bending moments besides a very significant tensile, rather than compressive weight bearing. Though rare, early diagnosis and treatment of the PTFJ dislocation are essential to prevent chronic joint instability and extensive surgical intervention to restore normal PTFJ biomechanics, ankle and knee function, especially in athletes prone to such injuries. PTFJ dislocations often remain undiagnosed in polytrauma scenario with ipsilateral tibial fracture due to the absence of specific signs and symptoms of PTFJ injury. Standard orthopedic textbooks generally describe no specific tests or radiological signs for assessment of the integrity of this joint. The aim of this paper was to review the relevant clinical anatomy, biomechanics and traumatic pathology of PTFJ with its effect on the knee emphasizing the importance of early diagnosis through a high index of suspicion. Dislocation of the joint may have serious implications for the knee joint stability since fibular collateral ligament and posterolateral ligament complex is attached to the upper end of the fibula. Any high energy knee injury with peroneal nerve palsy should immediately raise the suspicion of PTFJ dislocation especially if the mechanism of injury involved knee twisting in flexion beyond 80° and in such cases a comparative radiograph of the contralateral side should be performed. Wider clinical awareness can avoid both embarrassingly extensive surgeries due to diagnostic delays or unnecessary overtreatment due to misinformation on the part of the treating surgeon.

Endoscopic rendezvous procedure for ureteral iatrogenic detachment: report of a case series with long-term outcomes.

Science.gov (United States)

Pastore, Antonio Luigi; Palleschi, Giovanni; Silvestri, Luigi; Leto, Antonino; Autieri, Domenico; Ripoli, Andrea; Maggioni, Cristina; Al Salhi, Yazan; Carbone, Antonio

2015-04-01

Injury to the ureter is the most common urologic complication of pelvic surgery, with an incidence that ranges from 1% to 10%. Most cases of ureteral injuries are related to gynecologic procedures. The ureter is particularly vulnerable to detachment or ligation during hysterectomy because of its position from the lateral edge of the cervix. We report a case series of female patients who underwent the ureteral rendezvous procedure for ureteral detachment. Between January 2009 and April 2013, 18 ureteral rendezvous procedures were performed for patients with complete detachment. We assessed the operative and clinical outcomes of these patients over a mean follow-up duration of 26.5 months and describe the three most representative cases. The endoscopic rendezvous technique was performed in all cases to manage ureteral detachment. CT urography at discharge and 6 and 12 months after discharge confirmed the restoration of ureteral integrity without any leakage in 66% (12/18) patients, indicated ureteral stenosis in 22% (4/18) patients, and indicated ureteral leakage in 12% (2/18) patients. The overall long-term success rate for all 18 patients was 78% (14/18) at a mean follow-up of 26.5 months. The endoscopic rendezvous procedure reduces the need for invasive open surgical repair and represents the optimal initial option in patients with iatrogenic ureteral lesions before invasive procedures with higher morbidity are attempted.

Usage and User Experience of Communication before and during Rendezvous

Science.gov (United States)

Colbert, Martin

2005-01-01

This paper reports a field evaluation of the mobile phone as a "package" of device and services. The evaluation compares 44 university students' usage and user experience of communication before and during rendezvous. During a rendezvous (en route), students rated many aspects of the experience of phone use less favourably than before a rendezvous…

A Study of Control Laws for Microsatellite Rendezvous with a Noncooperative Target

National Research Council Canada - National Science Library

Tschirhart, Troy

2003-01-01

This study investigated the feasibility of using a microsatellite to accomplish an orbital rendezvous with a noncooperative target, with a focus on the control laws necessary for achieving such a rendezvous...

Autonomous vision-based navigation for proximity operations around binary asteroids

Science.gov (United States)

Gil-Fernandez, Jesus; Ortega-Hernando, Guillermo

2018-06-01

Future missions to small bodies demand higher level of autonomy in the Guidance, Navigation and Control system for higher scientific return and lower operational costs. Different navigation strategies have been assessed for ESA's asteroid impact mission (AIM). The main objective of AIM is the detailed characterization of binary asteroid Didymos. The trajectories for the proximity operations shall be intrinsically safe, i.e., no collision in presence of failures (e.g., spacecraft entering safe mode), perturbations (e.g., non-spherical gravity field), and errors (e.g., maneuver execution error). Hyperbolic arcs with sufficient hyperbolic excess velocity are designed to fulfil the safety, scientific, and operational requirements. The trajectory relative to the asteroid is determined using visual camera images. The ground-based trajectory prediction error at some points is comparable to the camera Field Of View (FOV). Therefore, some images do not contain the entire asteroid. Autonomous navigation can update the state of the spacecraft relative to the asteroid at higher frequency. The objective of the autonomous navigation is to improve the on-board knowledge compared to the ground prediction. The algorithms shall fit in off-the-shelf, space-qualified avionics. This note presents suitable image processing and relative-state filter algorithms for autonomous navigation in proximity operations around binary asteroids.

Fatal central venous air embolism: a rare complication of esophageal dilation by rendezvous.

Science.gov (United States)

Zald, Philip B; Andersen, Peter E

2011-03-01

Esophageal dilation by rendezvous is a useful technique for the treatment of complicated esophageal strictures. We present a case of a 74-year-old man with chronic dysphagia caused by a complete cervical esophageal stricture that developed after external beam radiotherapy for treatment of papillary thyroid carcinoma. During attempted dilation using the rendezvous technique, the patient suffered a fatal pulmonary air embolism. The technique of esophageal dilation by rendezvous, complications, and risk factors for development of venous air embolism are discussed. To the best of our knowledge, this is the first report in the literature of fatal venous air embolism after dilation by rendezvous. Copyright © 2009 Wiley Periodicals, Inc.

Orion Handling Qualities During ISS Rendezvous and Docking

Science.gov (United States)

Hart, Jeremy J.; Stephens, J. P.; Spehar, P.; Bilimoria, K.; Foster, C.; Gonzalex, R.; Sullivan, K.; Jackson, B.; Brazzel, J.; Hart, J.

2011-01-01

The Orion spacecraft was designed to rendezvous with multiple vehicles in low earth orbit (LEO) and beyond. To perform the required rendezvous and docking task, Orion must provide enough control authority to perform coarse translational maneuvers while maintaining precision to perform the delicate docking corrections. While Orion has autonomous docking capabilities, it is expected that final approach and docking operations with the International Space Station (ISS) will initially be performed in a manual mode. A series of evaluations was conducted by NASA and Lockheed Martin at the Johnson Space Center to determine the handling qualities (HQ) of the Orion spacecraft during different docking and rendezvous conditions using the Cooper-Harper scale. This paper will address the specifics of the handling qualities methodology, vehicle configuration, scenarios flown, data collection tools, and subject ratings and comments. The initial Orion HQ assessment examined Orion docking to the ISS. This scenario demonstrates the Translational Hand Controller (THC) handling qualities of Orion. During this initial assessment, two different scenarios were evaluated. The first was a nominal docking approach to a stable ISS, with Orion initializing with relative position dispersions and a closing rate of approximately 0.1 ft/sec. The second docking scenario was identical to the first, except the attitude motion of the ISS was modeled to simulate a stress case ( 1 degree deadband per axis and 0.01 deg/sec rate deadband per axis). For both scenarios, subjects started each run on final approach at a docking port-to-port range of 20 ft. Subjects used the THC in pulse mode with cues from the docking camera image, window views, and range and range rate data displayed on the Orion display units. As in the actual design, the attitude of the Orion vehicle was held by the automated flight control system at 0.5 degree deadband per axis. Several error sources were modeled including Reaction

Repeated rendezvous treatment of PTBD and ERCP in patients with recurrent obstructive jaundice.

Science.gov (United States)

Liu, Yingdi; Meng, Jianyun; Wang, Jianhua; Wang, Zhiqiang; Wang, Xiangdong; Linghu, Enqiang; Li, Wen; Yang, Yunsheng

2010-01-01

Repeated applications of rendezvous technique combining percutaneous transhepatic biliary drainage (PTBD) with endoscopic retrograde cholangiopancreatography (ERCP) (PE) in patients with recurrent obstructive jaundice have not been reported. The present study aimed to evaluate treatment effects of this technique in patients who previously received the same rendezvous treatment. Repeated PE rendezvous procedure was performed in 27 patients who received the same procedure previously and had recurrent obstructive jaundice. Twenty-two patients were treated by second-time rendezvous procedure and five patients by third-time. The clinical characteristics and therapeutic effects were retrospectively analyzed. By means of repeated rendezvous technique, 26 patients gained access to the bile duct and were successfully implanted new stents, only one failed with stent implantation. Total serum bilirubin level decreased within one week from 221.89 +/- 64.70 micromol/L to 156.0 +/- 32.2 micromol/L in patients with second-time treatment and from 297.07 +/- 109.12 micromol/L to 238.77 +/- 36.81 micromol/L in patients with third-time treatment. There was no severe complications observed that are associated with repeated PE procedure. Rendezvous procedure of PTBD and ERCP could be used repeatedly and effectively for patients who present recurrent obstructive jaundice after ERCP failure.

Percutaneous rendezvous technique for the management of a bile duct injury.

Science.gov (United States)

Meek, James; Fletcher, Savannah; Crumley, Kristen; Culp, W C; Meek, Mary

2018-02-01

The rendezvous technique typically involves combined efforts of interventional radiology, endoscopy, and surgery. It can be done solely percutaneously, whereby the interventionalist gains desired access to one point in the body by approaching it from two different access sites. We present the case of a woman who underwent cholecystectomy complicated by a bile duct injury. A percutaneous rendezvous procedure enabled placement of an internal-external drain from the intrahepatic ducts through the biloma and distal common bile duct and into the duodenum. Thus, a percutaneous rendezvous technique is feasible for managing a bile duct injury when endoscopic retrograde cholangio-pancreatography or percutaneous transhepatic cholangiogram alone has been unsuccessful.

Percutaneous rendezvous technique for the management of a bile duct injury

Directory of Open Access Journals (Sweden)

James Meek, DO

2018-02-01

Full Text Available The rendezvous technique typically involves combined efforts of interventional radiology, endoscopy, and surgery. It can be done solely percutaneously, whereby the interventionalist gains desired access to one point in the body by approaching it from two different access sites. We present the case of a woman who underwent cholecystectomy complicated by a bile duct injury. A percutaneous rendezvous procedure enabled placement of an internal-external drain from the intrahepatic ducts through the biloma and distal common bile duct and into the duodenum. Thus, a percutaneous rendezvous technique is feasible for managing a bile duct injury when endoscopic retrograde cholangio-pancreatography or percutaneous transhepatic cholangiogram alone has been unsuccessful.

Simultaneous Localization and Mapping for Satellite Rendezvous and Proximity Operations

Data.gov (United States)

National Aeronautics and Space Administration — Simultaneous Localization and Mapping (SLAM) attempts to estimate a vehicle’s position and orientation (localization) and the location of an initially unknown number...

Totally percutaneous rendezvous techniques for the treatment of bile strictures and leakages.

Science.gov (United States)

De Robertis, Riccardo; Contro, Alberto; Zamboni, Giulia; Mansueto, Giancarlo

2014-04-01

Some challenging pathologic conditions of the biliary tract cannot be treated with endoscopy alone, and a combined approach with rendezvous techniques is frequently needed. Three different totally percutaneous rendezvous techniques were successfully applied in three cases. The rendezvous techniques were performed either with bilateral catheterization of bile ducts to treat a challenging type IV biliary stenosis and iatrogenic biliary damage or with biliary catheterization and percutaneous puncture of the anastomotic loop to treat a biliodigestive anastomosis failure with bile leakage. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

A Modified Technique Reduced Operative Time of Laparoendoscopic Rendezvous Endoscopic Retrograde Cholangiopancreatography Combined with Laparoscopic Cholecystectomy for Concomitant Gallstone and Common Bile Ductal Stone

Directory of Open Access Journals (Sweden)

Wei Liu

2014-01-01

Full Text Available Laparoendoscopic rendezvous (LERV endoscopic retrograde cholangiopancreatography (ERCP and laparoscopic cholecystectomy (LC+ERCP/LERV are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1 from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2 who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9% in group 1 and 24 cases (86.2% in group 2. The mean operative time and time of endoscopic part were 82.6 ± 19.6 min and 26.5 ± 5.99 min in group 1 which were significantly shorter than those in group 2 (118.0 ± 23.1 min and 58.7 ± 13.3 min, resp.. There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique.

Modified rendezvous intrahepatic bile duct cannulation technique to pass a PTBD catheter in ERCP.

Science.gov (United States)

Lee, Tae Hoon; Park, Sang-Heum; Lee, Sae Hwan; Lee, Chang-Kyun; Lee, Suck-Ho; Chung, Il-Kwun; Kim, Hong Soo; Kim, Sun-Joo

2010-11-14

The rendezvous procedure combines an endoscopic technique with percutaneous transhepatic biliary drainage (PTBD). When a selective common bile duct cannulation fails, PTBD allows successful drainage and retrograde access for subsequent rendezvous techniques. Traditionally, rendezvous procedures such as the PTBD-assisted over-the-wire cannulation method, or the parallel cannulation technique, may be available when a bile duct cannot be selectively cannulated. When selective intrahepatic bile duct (IHD) cannulation fails, this modified rendezvous technique may be a feasible alternative. We report the case of a modified rendezvous technique, in which the guidewire was retrogradely passed into the IHD through the C2 catheter after end-to-end contact between the tips of the sphincterotome and the C2 catheter at the ampulla's orifice, in a 39-year-old man who had been diagnosed with gallbladder carcinoma with a metastatic right IHD obstruction. Clinically this procedure may be a feasible and timesaving technique.

Relationship between automation trust and operator performance for the novice and expert in spacecraft rendezvous and docking (RVD).

Science.gov (United States)

Niu, Jianwei; Geng, He; Zhang, Yijing; Du, Xiaoping

2018-09-01

Operator trust in automation is a crucial factor influencing its use and operational performance. However, the relationship between automation trust and performance remains poorly understood and requires further investigation. The objective of this paper is to explore the difference in trust and performance on automation-aided spacecraft rendezvous and docking (RVD) between the novice and the expert and to investigate the relationship between automation trust and performance as well. We employed a two-factor mixed design, with training skill (novice and expert) and automation mode (manual RVD and automation aided RVD) serving as the two factors. Twenty participants, 10 novices and 10 experts, were recruited to conduct six RVD tasks for two automation levels. After the tasks, operator performance was recorded by the desktop hand-held docking training equipment. Operator trust was also measured by a 12-items questionnaire at the beginning and end of each trial. As a result, automation narrowed the performance gap significantly between the novice and the expert, and the automation trust showed a marginally significant difference between the novice and the expert. Furthermore, the result demonstrated that the attitude angle control error of the expert was related to the total trust score, whereas other automation performance indicators were not related to the total score of trust. However, automation performance was related to the dimensions of trust, such as entrust, harmful, and dependable. Copyright © 2018 Elsevier Ltd. All rights reserved.

A modified Rendezvous ERCP technique in duodenal diverticulum.

Science.gov (United States)

Odabasi, Mehmet; Yildiz, Mehmet Kamil; Abuoglu, Haci Hasan; Eris, Cengiz; Ozkan, Erkan; Gunay, Emre; Aktekin, Ali; Muftuoglu, Ma Tolga

2013-11-16

To postoperative endoscopic retrograde cholangiopancreatography (ERCP) failure, we describe a modified Rendezvous technique for an ERCP in patients operated on for common bile duct stone (CBDS) having a T-tube with retained CBDSs. Five cases operated on for CBDSs and having retained stones with a T-tube were referred from other hospitals located in or around Istanbul city to the ERCP unit at the Haydarpasa Numune Education and Research Hospital. Under sedation anesthesia, a sterile guide-wire was inserted via the T-tube into the common bile duct (CBD) then to the papilla. A guide-wire was held by a loop snare and removed through the mouth. The guide-wire was inserted into the sphincterotome via the duodenoscope from the tip to the handle. The duodenoscope was inserted down to the duodenum with a sphincterotome and a guide-wire in the working channel. With the guidance of a guide-wire, the ERCP and sphincterotomy were successfully performed, the guide-wire was removed from the T-tube, the stones were removed and the CBD was reexamined for retained stones by contrast. An ERCP can be used either preoperatively or postoperatively. Although the success rate in an isolated ERCP treatment ranges from up to 87%-97%, 5%-10% of the patients require two or more ERCP treatments. If a secondary ERCP fails, the clinicians must be ready for a laparoscopic or open exploration. A duodenal diverticulum is one of the most common failures in an ERCP, especially in patients with an intradiverticular papilla. For this small group of patients, an antegrade cannulation via a T-tube can improve the success rate up to nearly 100%. The modified Rendezvous technique is a very easy method and increases the success of postoperative ERCP, especially in patients with large duodenal diverticula and with intradiverticular papilla.

Interactive orbital proximity operations planning system

Science.gov (United States)

Grunwald, Arthur J.; Ellis, Stephen R.

1990-01-01

An interactive graphical planning system for on-site planning of proximity operations in the congested multispacecraft environment about the space station is presented. The system shows the astronaut a bird's eye perspective of the space station, the orbital plane, and the co-orbiting spacecraft. The system operates in two operational modes: (1) a viewpoint mode, in which the astronaut is able to move the viewpoint around in the orbital plane to range in on areas of interest; and (2) a trajectory design mode, in which the trajectory is planned. Trajectory design involves the composition of a set of waypoints which result in a fuel-optimal trajectory which satisfies all operational constraints, such as departure and arrival constraints, plume impingement constraints, and structural constraints. The main purpose of the system is to present the trajectory and the constraints in an easily interpretable graphical format. Through a graphical interactive process, the trajectory waypoints are edited until all operational constraints are satisfied. A series of experiments was conducted to evaluate the system. Eight airline pilots with no prior background in orbital mechanics participated in the experiments. Subject training included a stand-alone training session of about 6 hours duration, in which the subjects became familiar with orbital mechanics concepts and performed a series of exercises to familiarize themselves with the control and display features of the system. They then carried out a series of production runs in which 90 different trajectory design situations were randomly addressed. The purpose of these experiments was to investigate how the planning time, planning efforts, and fuel expenditures were affected by the planning difficulty. Some results of these experiments are presented.

Endoscopic ultrasonography-guided rendezvous technique.

Science.gov (United States)

Tsuchiya, Takayoshi; Itoi, Takao; Sofuni, Atsushi; Tonozuka, Ryosuke; Mukai, Shuntaro

2016-04-01

Endoscopic retrograde cholangiopancreatography (ERCP) requires deep biliary cannulation. When deep biliary cannulation is failed, the endoscopic ultrasonography rendezvous technique (EUS-RV) is a useful salvage method. From the previous 15 articles that included 382 EUS-RV cases, the overall success rate of EUS-RV is 81 % with a complication rate of 10 %. In EUS-RV, the bile duct is punctured under EUS guidance and a guidewire is advanced into the duodenum via the papilla. The EUS scope is then switched to a duodenoscope and inserted into the bile duct over the guidewire exiting the papilla, or the guidewire is grasped with forceps and passed through the working channel; the catheter can then be inserted through the papilla over the wire. There are three puncture routes for EUS-RV: transgastric puncture of the intrahepatic bile duct (IHBD), transduodenal puncture of the extrahepatic bile duct (EHBD) via the proximal duodenum (D1), and transduodenal puncture of the EHBD via the second portion of the duodenum (D2). The puncture route for each patient should be selected based on the patient condition. GW selection for EUS-RV is critical, a hydrophilic GW is useful for this procedure. Although EUS-RV is now performed relatively routinely in a few high-volume centers, procedure standardization and the development of exclusive devices for EUS-RV are still underway. The development of exclusive devices for EUS-RV and prospective comparative studies with other salvage methods are needed to truly evaluate the procedure's usefulness and safety.

Over-the-catheter precut to gain access to the biliary duct during ERCP rendezvous.

Science.gov (United States)

Manes, Gianpiero; Baratti, Cinzia; Ardizzone, Sandro; Ferla, Fabio; Spiropoulos, Jean; Corsi, Fabio; Foschi, Diego; Trabucchi, Emilio; Bianchi Porro, Gabriele

2008-10-01

Endoscopic retrograde cholangiopancreatography (ERCP) rendezvous during laparoscopic cholecystectomy is an efficient and safe method to treat cholecystocholedocholithiasis. Advancing a guidewire through the cystic duct into the duodenum and withdrawing it in the accessory channel of duodenoscope may be, however, laborious. Moreover, rendezvous performed in the typical manner needs the use of several costly accessories. We herein describe a simpler and cheaper method to gain access to the biliary duct at rendezvous. Twenty-four consecutive patients undergoing ERCP rendezvous during laparoscopic cholecystectomy were considered. A catheter was introduced in the cystic duct and advanced into the duodenum. Access to the bile duct was than achieved by means of a precut sphincterotomy performed over the catheter emerging from the papilla. Cannulation was successful in all but two patients, in whom ERCP was performed in the conventional manner. The only complication was a case of mild post-sphincterotomy bleeding. In comparison with the typical rendezvous technique our procedure allowed savings of about 250, since its performance only requires a catheter and a knife sphincterotome. Over-the-catheter precut during ERCP rendezvous is a feasible and safe method which avoids the need for the manipulation of several accessories and guidewires, and thus results in money and time savings.

Multiple NEO Rendezvous Using Solar Sails

Science.gov (United States)

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

Mission concept is to assess the feasibility of using solar sail propulsion to enable a robotic precursor that would survey multiple Near Earth Objects (NEOs) for potential future human visits. Single spacecraft will rendezvous with and image 3 NEOs within 6 years of launch

Optimal Non-Coplanar Launch to Quick Rendezvous

National Research Council Canada - National Science Library

Sears, Gregory

1997-01-01

The purpose of this study was to determine the feasibility of launching a Delta Clipper-like vehicle on an optimal, non-coplanar trajectory to rendezvous with an earth orbiting object in one orbit or less...

Smartphone Video Guidance Sensor for Small Satellites

Data.gov (United States)

National Aeronautics and Space Administration — Smartphone Video Guidance Sensor(SVGS) for Small Satellites will provide a low-cost,integrated rendezvous & proximity operations sensor system to allow an...

Rendezvous maneuvers using Genetic Algorithm

International Nuclear Information System (INIS)

Dos Santos, Denílson Paulo Souza; De Almeida Prado, Antônio F Bertachini; Teodoro, Anderson Rodrigo Barretto

2013-01-01

The present paper has the goal of studying orbital maneuvers of Rendezvous, that is an orbital transfer where a spacecraft has to change its orbit to meet with another spacecraft that is travelling in another orbit. This transfer will be accomplished by using a multi-impulsive control. A genetic algorithm is used to find the transfers that have minimum fuel consumption

Tangent Orbital Rendezvous Using Linear Relative Motion with J2 Perturbations

Directory of Open Access Journals (Sweden)

Gang Zhang

2013-01-01

Full Text Available The tangent-impulse coplanar orbit rendezvous problem is studied based on the linear relative motion for J2-perturbed elliptic orbits. There are three cases: (1 only the first impulse is tangent; (2 only the second impulse is tangent; (3 both impulses are tangent. For a given initial impulse point, the first two problems can be transformed into finding all roots of a single variable function about the transfer time, which can be done by the secant method. The bitangent rendezvous problem requires the same solution for the first two problems. By considering the initial coasting time, the bitangent rendezvous solution is obtained with a difference function. A numerical example for two coplanar elliptic orbits with J2 perturbations is given to verify the efficiency of these proposed techniques.

Optimal starting conditions for the rendezvous maneuver: Analytical and computational approach

Science.gov (United States)

Ciarcia, Marco

The three-dimensional rendezvous between two spacecraft is considered: a target spacecraft on a circular orbit around the Earth and a chaser spacecraft initially on some elliptical orbit yet to be determined. The chaser spacecraft has variable mass, limited thrust, and its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We seek the time history of the controls in such a way that the propellant mass required to execute the rendezvous maneuver is minimized. Two cases are considered: (i) time-to-rendezvous free and (ii) time-to-rendezvous given, respectively equivalent to (i) free angular travel and (ii) fixed angular travel for the target spacecraft. The above problem has been studied by several authors under the assumption that the initial separation coordinates and the initial separation velocities are given, hence known initial conditions for the chaser spacecraft. In this paper, it is assumed that both the initial separation coordinates and initial separation velocities are free except for the requirement that the initial chaser-to-target distance is given so as to prevent the occurrence of trivial solutions. Two approaches are employed: optimal control formulation (Part A) and mathematical programming formulation (Part B). In Part A, analyses are performed with the multiple-subarc sequential gradient-restoration algorithm for optimal control problems. They show that the fuel-optimal trajectory is zero-bang, namely it is characterized by two subarcs: a long coasting zero-thrust subarc followed by a short powered max-thrust braking subarc. While the thrust direction of the powered subarc is continuously variable for the optimal trajectory, its replacement with a constant (yet optimized) thrust direction produces a very efficient guidance trajectory. Indeed, for all values of the initial distance, the fuel required by the guidance trajectory is within less than one percent of the fuel required

The Next Generation Advanced Video Guidance Sensor: Flight Heritage and Current Development

Science.gov (United States)

Howard, Richard T.; Bryan, Thomas C.

2009-01-01

The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. This paper presents the flight heritage and results of the sensor technology, some hardware trades for the current sensor, and discusses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the various NGAVGS development units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.

Endoscopic Sphincterotomy Using the Rendezvous Technique for Choledocholithiasis during Laparoscopic Cholecystectomy: A Case Report.

Science.gov (United States)

Tanaka, Takayuki; Haraguchi, Masashi; Tokai, Hirotaka; Ito, Shinichiro; Kitajima, Masachika; Ohno, Tsuyoshi; Onizuka, Shinya; Inoue, Keiji; Motoyoshi, Yasuhide; Kuroki, Tamotsu; Kanemastu, Takashi; Eguchi, Susumu

2014-05-01

A 50-year-old male was examined at another hospital for fever, general fatigue and slight abdominal pain. He was treated with antibiotics and observed. However, his symptoms did not lessen, and laboratory tests revealed liver dysfunction, jaundice and an increased inflammatory response. He was then admitted to our hospital and underwent an abdominal computed tomography scan and magnetic resonance cholangiopancreatography (MRCP), which revealed common bile duct (CBD) stones. He was diagnosed with mild acute cholangitis. As the same time, he was admitted to our hospital and an emergency endoscopic retrograde cholangiopancreatography was performed. Vater papilla opening in the third portion of the duodenum and presence of a peripapillary duodenal diverticulum made it difficult to perform cannulation of the CBD. In addition, MRCP revealed that the CBD was extremely narrow (diameter 5 mm). We therefore performed laparoscopic cholecystectomy and endoscopic sphincterotomy using the rendezvous technique for choledocholithiasis simultaneously rather than laparoscopic CBD exploration. After the operation, the patient was discharged with no complications. Although the rendezvous technique has not been very commonly used because several experts in the technique and a large operating room are required, this technique is a very attractive and effective approach for treating choledocholithiasis, for which endoscopic treatment is difficult.

Endoscopic Sphincterotomy Using the Rendezvous Technique for Choledocholithiasis during Laparoscopic Cholecystectomy: A Case Report

Directory of Open Access Journals (Sweden)

Takayuki Tanaka

2014-08-01

Full Text Available A 50-year-old male was examined at another hospital for fever, general fatigue and slight abdominal pain. He was treated with antibiotics and observed. However, his symptoms did not lessen, and laboratory tests revealed liver dysfunction, jaundice and an increased inflammatory response. He was then admitted to our hospital and underwent an abdominal computed tomography scan and magnetic resonance cholangiopancreatography (MRCP, which revealed common bile duct (CBD stones. He was diagnosed with mild acute cholangitis. As the same time, he was admitted to our hospital and an emergency endoscopic retrograde cholangiopancreatography was performed. Vater papilla opening in the third portion of the duodenum and presence of a peripapillary duodenal diverticulum made it difficult to perform cannulation of the CBD. In addition, MRCP revealed that the CBD was extremely narrow (diameter 5 mm. We therefore performed laparoscopic cholecystectomy and endoscopic sphincterotomy using the rendezvous technique for choledocholithiasis simultaneously rather than laparoscopic CBD exploration. After the operation, the patient was discharged with no complications. Although the rendezvous technique has not been very commonly used because several experts in the technique and a large operating room are required, this technique is a very attractive and effective approach for treating choledocholithiasis, for which endoscopic treatment is difficult.

Percutaneous-endoscopic rendezvous procedure for the management of bile duct injuries after cholecystectomy: short- and long-term outcomes.

Science.gov (United States)

Schreuder, Anne Marthe; Booij, Klaske A C; de Reuver, Philip R; van Delden, Otto M; van Lienden, Krijn P; Besselink, Marc G; Busch, Olivier R; Gouma, Dirk J; Rauws, Erik A J; van Gulik, Thomas M

2018-01-19

 Bile duct injury (BDI) remains a daunting complication of laparoscopic cholecystectomy. In patients with complex BDI, a percutaneous-endoscopic rendezvous procedure may be required to establish bile duct continuity. The aim of this study was to assess short- and long-term outcomes of the rendezvous procedure.  All consecutive patients with BDI referred to our tertiary referral center between 1995 and 2016 were analyzed. A rendezvous procedure was performed when endoscopic or radiologic intervention failed, and when deemed feasible by a dedicated multidisciplinary team including hepatopancreaticobiliary surgeons, gastrointestinal endoscopists, and interventional radiologists. Classification of BDI, technical success of the rendezvous procedure, procedure-related adverse events, and outcomes were assessed.  Among a total of 812 patients, rendezvous was performed in 47 (6 %), 31 (66 %) of whom were diagnosed with complete transection of the bile duct (Amsterdam type D/Strasberg type E injury). The primary success rate of rendezvous was 94 % (44 /47 patients). Overall morbidity was 18 % (10 /55 procedures). No life-threatening adverse events or 90-day mortality occurred. After a median follow-up of 40 months (interquartile range 23 - 54 months), rendezvous was the final successful treatment in 26 /47 patients (55 %). In 14 /47 patients (30 %), rendezvous acted as a bridge to surgery, with hepaticojejunostomy being chosen either primarily or secondarily to treat refractory or relapsing stenosis. In experienced hands, rendezvous was a safe procedure, with a long-term success rate of 55 %. When endoscopic or transhepatic interventions fail to restore bile duct continuity in patients with BDI, rendezvous should be considered, either as definitive treatment or as a bridge to elective surgery. © Georg Thieme Verlag KG Stuttgart · New York.

Interesting rendezvous location in a liver transplantation patient with anastomosis stricture.

Science.gov (United States)

Odemis, Bulent; Oztas, Erkin; Yurdakul, Mehmet; Torun, Serkan; Suna, Nuredtin; Kayacetin, Ertugrul

2014-11-14

An endoscopic or radiologic percutaneous approach may be an initial minimally invasive method for treating biliary strictures after living donor liver transplantation; however, cannulation of biliary strictures is sometimes difficult due to the presence of a sharp or twisted angle within the stricture or a complete stricture. When an angulated or twisted biliary stricture interrupts passage of a guidewire over the stricture, it is difficult to replace the percutaneous biliary drainage catheter with inside stents by endoscopic retrograde cholangiopancreatography. The rendezvous technique can be used to overcome this difficulty. In addition to the classical rendezvous method, in cases with complete transection of the common bile duct a modified technique involving the insertion of a snare into the subhepatic space has been successfully performed. Herein, we report a modified rendezvous technique in the duodenal bulb as an extraordinary location for a patient with duct-to-duct anastomotic complete stricture after liver transplantation.

Spheres: from Ground Development to ISS Operations

Science.gov (United States)

Katterhagen, A.

2016-01-01

SPHERES (Synchronized Position Hold Engage and Reorient Experimental Satellites) is an internal International Space Station (ISS) Facility that supports multiple investigations for the development of multi-spacecraft and robotic control algorithms. The SPHERES National Lab Facility aboard ISS is managed and operated by NASA Ames Research Center (ARC) at Moffett Field California. The SPHERES Facility on ISS consists of three self-contained eight-inch diameter free-floating satellites which perform the various flight algorithms and serve as a platform to support the integration of experimental hardware. SPHERES has served to mature the adaptability of control algorithms of future formation flight missions in microgravity (6 DOF (Degrees of Freedom) / long duration microgravity), demonstrate key close-proximity formation flight and rendezvous and docking maneuvers, understand fault diagnosis and recovery, improve the field of human telerobotic operation and control, and lessons learned on ISS have significant impact on ground robotics, mapping, localization, and sensing in three-dimensions - among several other areas of study.

Rendezvous procedure for the treatment of bile leaks and injury following segmental hepatectomy.

Science.gov (United States)

Nasr, John Y; Hashash, Jana G; Orons, Philip; Marsh, Wallis; Slivka, Adam

2013-05-01

Endoscopic retrograde cholangiopancreatography is a minimally invasive procedure used for the evaluation and management of biliary injuries. At times, ERCP fails and percutaneous modalities may be required. Rendezvous procedures are combined endoscopic and percutaneous techniques that have been used to restore anatomic continuity and biliary drainage in cases where retrograde and/or transhepatic access alone has failed either due to anatomic variation or traumatic injury with biloma formation. To assess if the Rendezvous technique plays a role in establishing biliary continuity in patients with a bile leak after segmental hepatectomy. We herby present a series of 3 patients who had complex bile leaks after segmental liver resection and underwent a combined percutaneous and endoscopic Rendezvous procedure to establish biliary continuity. This technique was successful in restoring biliary continuity and avoiding hepaticojejunostomy in 2 of the 3 patients. The Rendezvous technique may play a role in establishing biliary continuity in patients with biliary leak secondary to hepatic surgery. Copyright © 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

An automated rendezvous and capture system design concept for the cargo transfer vehicle and Space Station Freedom

Science.gov (United States)

Fuchs, Ron; Marsh, Steven

1991-01-01

A rendezvous sensor system concept was developed for the cargo transfer vehicle (CTV) to autonomously rendezvous with and be captured by Space Station Freedom (SSF). The development of requirements, the design of a unique Lockheed developed sensor concept to meet these requirements, and the system design to place this sensor on the CTV and rendezvous with the SSF are described .

Autonomous spacecraft rendezvous and docking

Science.gov (United States)

Tietz, J. C.; Almand, B. J.

A storyboard display is presented which summarizes work done recently in design and simulation of autonomous video rendezvous and docking systems for spacecraft. This display includes: photographs of the simulation hardware, plots of chase vehicle trajectories from simulations, pictures of the docking aid including image processing interpretations, and drawings of the control system strategy. Viewgraph-style sheets on the display bulletin board summarize the simulation objectives, benefits, special considerations, approach, and results.

The factors influencing the decision making of operative treatment for proximal humeral fractures

NARCIS (Netherlands)

Hageman, Michiel G. J. S.; Jayakumar, Prakash; King, John D.; Guitton, Thierry G.; Doornberg, Job N.; Ring, David

2015-01-01

The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information. Secondarily, we

The factors influencing the decision making of operative treatment for proximal humeral fractures

NARCIS (Netherlands)

Hageman, M.G.; Jayakumar, P.; King, J.D.; Guitton, T.G.; Doornberg, J.N.; Ring, D.; Poelhekke, L.M.S.J.; et al.,

2015-01-01

BACKGROUND: The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information.

Observer-Based Robust Control for Spacecraft Rendezvous with Thrust Saturation

Directory of Open Access Journals (Sweden)

Neng Wan

2014-01-01

Full Text Available This paper proposes an observer-based robust guaranteed cost control method for thrust-limited rendezvous in near-circular orbits. Treating the noncircularity of the target orbit as a parametric uncertainty, a linearized motion model derived from the two-body problem is adopted as the controlled plant. Based on this model, a robust guaranteed cost observer-controller is synthesized with a less conservative saturation control law, and sufficient condition for the existence of this observer-based rendezvous controller is derived. Finally, an illustrative example with immeasurable velocity states is presented to demonstrate the advantages and effectiveness of the control scheme.

Rendezvous and Docking Technology for Space Flight%空间交会对接技术

Institute of Scientific and Technical Information of China (English)

郑永煌

2011-01-01

空间交会对接是载人航天工程非常重要的基本技术.在介绍空间交会对接技术发展历史和中国首次交会对接取得圆满成功的基础上,阐述了空间交会对接技术的基本概念、技术难点、控制方式和交会对接过程,并着重介绍了四种交会对接机构的特点.最后介绍了中国首次交会对接任务规划、天宫一号目标飞行器和神舟八号飞船的特点以及两次空间交会对接过程.%Rendezvous and Docking is a very important basic technology of Manned Space Engineering. Firstly, rendezvous and docking technology development history is provided, and the significance of China first rendezvous and docking success is presented. Secondly, the basic conception, technology difficulty, control mode and docking process of rendezvous and docking technology are explained.Thirdly, four docking mechanism characteristics are special provided. Finally, China first rendezvous and docking mission planning,characteristic of Tiangong-1 target flight vehicle and Shenzhou-8 spacecraft and two rendezvous and docking successes are presented.

Usefulness of combined percutaneous-endoscopic rendezvous techniques after failed therapeutic endoscopic retrograde cholangiography in the era of endoscopic ultrasound guided rendezvous.

Science.gov (United States)

Yang, Min Jae; Kim, Jin Hong; Hwang, Jae Chul; Yoo, Byung Moo; Kim, Soon Sun; Lim, Sun Gyo; Won, Je Hwan

2017-12-01

The rendezvous approach is a salvage technique after failure of endoscopic retrograde cholangiography (ERC). In certain circumstances, percutaneous-endoscopic rendezvous (PE-RV) is preferred, and endoscopic ultrasound-guided rendezvous (EUS-RV) is difficult to perform. We aimed to evaluate PE-RV outcomes, describe the PE-RV techniques, and identify potential indications for PE-RV over EUS-RV.Retrospective analysis was conducted of a prospectively designed ERC database between January 2005 and December 2016 at a tertiary referral center including cases where PE-RV was used as a salvage procedure after ERC failure.During the study period, PE-RV was performed in 42 cases after failed therapeutic ERC; 15 had a surgically altered enteric anatomy. The technical success rate of PE-RV was 92.9% (39/42), with a therapeutic success rate of 88.1% (37/42). Potential indications for PE-RV over EUS-RV were identified in 23 cases, and either PE-RV or EUS-RV could have effectively been used in 19 cases. Endoscopic bile duct access was successfully achieved with PE-RV in 39 cases with accessible biliary orifice using one of PE-RV cannulation techniques (classic, n = 11; parallel, n = 19; and adjunctive maneuvers, n = 9).PE-RV uses a unique technology and has clinical indications that distinguish it from EUS-RV. Therefore, PE-RV can still be considered a useful salvage technique for the treatment of biliary obstruction after ERC failure.

Robust Tracking Control for Rendezvous in Near-Circular Orbits

Directory of Open Access Journals (Sweden)

Neng Wan

2013-01-01

Full Text Available This paper investigates a robust guaranteed cost tracking control problem for thrust-limited spacecraft rendezvous in near-circular orbits. Relative motion model is established based on the two-body problem with noncircularity of the target orbit described as a parameter uncertainty. A guaranteed cost tracking controller with input saturation is designed via a linear matrix inequality (LMI method, and sufficient conditions for the existence of the robust tracking controller are derived, which is more concise and less conservative compared with the previous works. Numerical examples are provided for both time-invariant and time-variant reference signals to illustrate the effectiveness of the proposed control scheme when applied to the terminal rendezvous and other astronautic missions with scheduled states signal.

Intra-urinoma Rendezvous Using a Transconduit Approach to Re-establish Ureteric Integrity

International Nuclear Information System (INIS)

Anderson, Hugh; Alyas, Faisal; Edwin, Patrick Joseph

2005-01-01

Ureteric discontinuity following injury has been traditionally treated surgically. With the advent of improved interventional instrumentation it is possible to stent these lesions percutaneously, retrogradely or failing that using a combined (rendezvous) technique. We describe an intra-urinoma rendezvous procedure combining a percutaneous antegrade-transconduit retrograde technique of stent insertion to successfully re-establish ureteric integrity that was used following the failure of a percutaneous retrograde approach. We illustrate its usefulness as an alternative to surgery

Robust H∞ Control for Spacecraft Rendezvous with a Noncooperative Target

Directory of Open Access Journals (Sweden)

Shu-Nan Wu

2013-01-01

Full Text Available The robust H∞ control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H∞ performance and finite time performance are proposed, and a robust H∞ controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

The Effect of Air Drag in Optimal Power-Limited Rendezvous Between Coplanar Low-Earth Orbits

Directory of Open Access Journals (Sweden)

Gil-Young Maeng

1998-06-01

Full Text Available The effect of air drag was researched when a low-earth orbit spacecraft using power-limited thruster rendezvoused another low-earth orbit spacecraft. The air density was assumed to decrease exponentially. The radius of parking orbit was 6655.935 km and that of target orbit was 7321.529 km. From the trajectories of active vehicles, the fuel consumption and the magnitude of thrust acceleration, we could conclude that the effect of air drag had to be considered in fuel optimal rendezvous problem between low-earth orbit spacecrafts. In multiple-revolution rendezvous case, the air drag was more effective.

A Monocular SLAM Method to Estimate Relative Pose During Satellite Proximity Operations

Science.gov (United States)

2015-03-26

Truth rotation values are obtained from the spot of a laser pointer that is fixed to the CubeSat and points 76 Figure 44. The AFIT 6U CubeSat Air Bearing...Demonstration for Autonomous Rendezvous Technology (DART) spacecraft, which irradiates retro-reflectors of a known orienta- tion with a laser to solve the...minimize the additional sub-system requirements on the spacecraft. Most spacecraft already have star trackers , which use dedicated CPUs to perform stellar

Pancreatic duct drainage using EUS-guided rendezvous technique for stenotic pancreaticojejunostomy.

Science.gov (United States)

Takikawa, Tetsuya; Kanno, Atsushi; Masamune, Atsushi; Hamada, Shin; Nakano, Eriko; Miura, Shin; Ariga, Hiroyuki; Unno, Jun; Kume, Kiyoshi; Kikuta, Kazuhiro; Hirota, Morihisa; Yoshida, Hiroshi; Katayose, Yu; Unno, Michiaki; Shimosegawa, Tooru

2013-08-21

The patient was a 30-year-old female who had undergone excision of the extrahepatic bile duct and Roux-en-Y hepaticojejunostomy for congenital biliary dilatation at the age of 7. Thereafter, she suffered from recurrent acute pancreatitis due to pancreaticobiliary maljunction and received subtotal stomach-preserving pancreaticoduodenectomy. She developed a pancreatic fistula and an intra-abdominal abscess after the operation. These complications were improved by percutaneous abscess drainage and antibiotic therapy. However, upper abdominal discomfort and the elevation of serum pancreatic enzymes persisted due to stenosis from the pancreaticojejunostomy. Because we could not accomplish dilation of the stenosis by endoscopic retrograde cholangiopancreatography, we tried an endoscopic ultrasonography (EUS) guided rendezvous technique for pancreatic duct drainage. After transgastric puncture of the pancreatic duct using an EUS-fine needle aspiration needle, the guidewire was inserted into the pancreatic duct and finally reached to the jejunum through the stenotic anastomosis. We changed the echoendoscope to an oblique-viewing endoscope, then grasped the guidewire and withdrew it through the scope. The stenosis of the pancreaticojejunostomy was dilated up to 4 mm, and a pancreatic stent was put in place. Though the pancreatic stent was removed after three months, the patient remained symptom-free. Pancreatic duct drainage using an EUS-guided rendezvous technique was useful for the treatment of a stenotic pancreaticojejunostomy after pancreaticoduodenectomy.

Diagnosis of false proximal anastomosis aneurysms after aortofemoral reconstructive operations

International Nuclear Information System (INIS)

Pokrovskij, A.V.; Dan, V.N.; Karazeev, G.L.

1993-01-01

The paper deals with the diagnostic aspects of false aneurysms of proximal anastomosis of prostheses with the aorta on the basis of examination of 9 patients aged 3-65 years after aortofemoral reconstructive operations. The periods of the occurrence of false aneurysms were 2 weeks to 6 years. The causes of anastomosis aneurysms: infection, endartectomy fro the aorta at the site of applied anastomosis, progressive underlying disease. The authors provide strong evidence for a high informative value of various examinations, including ultrasound echoscanning, computer tomography, radioopaque aortography

Comparison of EUS-guided rendezvous and precut papillotomy techniques for biliary access (with videos).

Science.gov (United States)

Dhir, Vinay; Bhandari, Suryaprakash; Bapat, Mukta; Maydeo, Amit

2012-02-01

Precut papillotomy after failed bile duct cannulation is associated with an increased risk of pancreatitis. EUS-guided rendezvous drainage is a novel alternative technique, but there are no data comparing this approach with precut papillotomy. To evaluate the safety and efficacy of EUS-guided rendezvous drainage of the bile duct and compare its outcome with that of precut papillotomy. Retrospective study. Tertiary care referral center. Consecutive patients with distal bile duct obstruction, in whom selective cannulation of the bile duct at ERCP failed after 5 attempts with a guidewire and sphincterotome, underwent an EUS-guided rendezvous procedure. The outcomes were compared with those in a historical cohort of patients who underwent precut papillotomy. Patients in whom selective cannulation failed underwent EUS-guided rendezvous drainage by use of the short wire technique or precut papillotomy by use of the Erlangen papillotome. At EUS, after the extrahepatic bile duct was punctured with a 19-gauge needle, a hydrophilic angled-tip guidewire 260 cm long was passed in an antegrade manner across the papilla into the duodenum. The echoendoscope was then exchanged for a duodenoscope, which was introduced alongside the EUS-placed guidewire. The transpapillary guidewire was retrieved through its biopsy channel, and accessories were passed over the wire to perform the requisite endotherapy. Comparison of the rates of technical success and complications between patients treated by the EUS-guided rendezvous and those treated by precut papillotomy techniques. Treatment success was defined as completion of the requisite endotherapy in one treatment session. Treatment success was significantly higher for the EUS-guided rendezvous (57/58 patients) than for those undergoing precut papillotomy technique (130/144 patients) (98.3% vs 90.3%; P = .03). There was no significant difference in the rate of procedural complications between the EUS and precut papillotomy techniques (3

Source tracking swine fecal waste in surface water proximal to swine concentrated animal feeding operations.

Science.gov (United States)

Heaney, Christopher D; Myers, Kevin; Wing, Steve; Hall, Devon; Baron, Dothula; Stewart, Jill R

2015-04-01

Swine farming has gone through many changes in the last few decades, resulting in operations with a high animal density known as confined animal feeding operations (CAFOs). These operations produce a large quantity of fecal waste whose environmental impacts are not well understood. The purpose of this study was to investigate microbial water quality in surface waters proximal to swine CAFOs including microbial source tracking of fecal microbes specific to swine. For one year, surface water samples at up- and downstream sites proximal to swine CAFO lagoon waste land application sites were tested for fecal indicator bacteria (fecal coliforms, Escherichia coli and Enterococcus) and candidate swine-specific microbial source-tracking (MST) markers (Bacteroidales Pig-1-Bac, Pig-2-Bac, and Pig-Bac-2, and methanogen P23-2). Testing of 187 samples showed high fecal indicator bacteria concentrations at both up- and downstream sites. Overall, 40%, 23%, and 61% of samples exceeded state and federal recreational water quality guidelines for fecal coliforms, E. coli, and Enterococcus, respectively. Pig-1-Bac and Pig-2-Bac showed the highest specificity to swine fecal wastes and were 2.47 (95% confidence interval [CI]=1.03, 5.94) and 2.30 times (95% CI=0.90, 5.88) as prevalent proximal down- than proximal upstream of swine CAFOs, respectively. Pig-1-Bac and Pig-2-Bac were also 2.87 (95% CI=1.21, 6.80) and 3.36 (95% CI=1.34, 8.41) times as prevalent when 48 hour antecedent rainfall was greater than versus less than the mean, respectively. Results suggest diffuse and overall poor sanitary quality of surface waters where swine CAFO density is high. Pig-1-Bac and Pig-2-Bac are useful for tracking off-site conveyance of swine fecal wastes into surface waters proximal to and downstream of swine CAFOs and during rain events. Copyright © 2014 Elsevier B.V. All rights reserved.

Near-Earth Asteroid Rendezvous: mission overview

Science.gov (United States)

Cheng, A. F.; Santo, A. G.; Heeres, K. J.; Landshof, J. A.; Farquhar, R. W.; Gold, R. E.; Lee, S. C.

1997-10-01

The Near-Earth Asteroid Rendezvous (NEAR) mission, the first launch of NASA's Discovery Program, will be the first mission to orbit an asteroid. NEAR will make the first comprehensive scientific measurements of an asteroid's surface composition, geology, physical properties, and internal structure. NEAR launched successfully on February 17, 1996, aboard a Delta II-7925. It will orbit the 20-km-diameter near-Earth asteroid 433 Eros for about 1 year, at a minimum orbit radius of about 35 km from the center of the asteroid. The NEAR is a solar-powered, three-axis stabilized spacecraft with a launch mass including propellant of 805 kg. NEAR uses X band telemetry to the NASA Deep Space Network, with the data rates at Eros up to 8.8 kbits/s using a 34-m High Efficiency (HEF) dish, and up to 26.5 kbits/s using a 70-m dish. A solid-state recorder is accommodated with a memory capacity of 1.8 Gbytes. Attitude control is to 1.7 mrad, line-of-sight pointing stability is within 50 μrad over 1 s, and post processing attitude knowledge is within 50 μrad. NEAR accommodates 56 kg of instruments and provides them with 84 W. The instruments are a multispectral imager (MSI), a near-infrared spectrograph (NIS), an X ray/gamma ray spectrometer (XRS/GRS), a magnetometer (MAG), and a laser rangefinder (NLR), while a radio science (RS) investigation uses the coherent X band transponder. NEAR will make a flyby of the C-type asteroid 253 Mathilde in June 1997 and will rendezvous with 433 Eros in February 1999. It will execute an initial slow flyby of Eros, with a flyby speed of 5 m/s and a closest approach distance of 500 km. Subsequently, its orbit will be lowered to 35 km. The NEAR Mission Operations Center and the Science Data Center are at the Johns Hopkins Applied Physics Laboratory. The Science Data Center will maintain the entire NEAR data set on-line, and data from all instruments can be accessed by every member of the NEAR Science Team. Data, including images, are released over

A Human Proximity Operations System test case validation approach

Science.gov (United States)

Huber, Justin; Straub, Jeremy

A Human Proximity Operations System (HPOS) poses numerous risks in a real world environment. These risks range from mundane tasks such as avoiding walls and fixed obstacles to the critical need to keep people and processes safe in the context of the HPOS's situation-specific decision making. Validating the performance of an HPOS, which must operate in a real-world environment, is an ill posed problem due to the complexity that is introduced by erratic (non-computer) actors. In order to prove the HPOS's usefulness, test cases must be generated to simulate possible actions of these actors, so the HPOS can be shown to be able perform safely in environments where it will be operated. The HPOS must demonstrate its ability to be as safe as a human, across a wide range of foreseeable circumstances. This paper evaluates the use of test cases to validate HPOS performance and utility. It considers an HPOS's safe performance in the context of a common human activity, moving through a crowded corridor, and extrapolates (based on this) to the suitability of using test cases for AI validation in other areas of prospective application.

Automated rendezvous and capture development infrastructure

Science.gov (United States)

Bryan, Thomas C.; Roe, Fred; Coker, Cynthia

1992-01-01

The facilities at Marshall Space Flight Center and JSC to be utilized to develop and test an autonomous rendezvous and capture (ARC) system are described. This includes equipment and personnel facility capabilities to devise, develop, qualify, and integrate ARC elements and subsystems into flight programs. Attention is given to the use of a LEO test facility, the current concept and unique system elements of the ARC, and the options available to develop ARC technology.

Optimal Rendezvous and Docking Simulator for Elliptical Orbits, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — It is proposed to develop and implement a simulation of spacecraft rendezvous and docking guidance, navigation, and control in elliptical orbit. The foundation of...

Robust H(∞) control for spacecraft rendezvous with a noncooperative target.

Science.gov (United States)

Wu, Shu-Nan; Zhou, Wen-Ya; Tan, Shu-Jun; Wu, Guo-Qiang

2013-01-01

The robust H(∞) control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H(∞) performance and finite time performance are proposed, and a robust H(∞) controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

Space Shuttle Guidance, Navigation, and Rendezvous Knowledge Capture Reports. Revision 1

Science.gov (United States)

Goodman, John L.

2011-01-01

This document is a catalog and readers guide to lessons learned, experience, and technical history reports, as well as compilation volumes prepared by United Space Alliance personnel for the NASA/Johnson Space Center (JSC) Flight Dynamics Division.1 It is intended to make it easier for future generations of engineers to locate knowledge capture documentation from the Shuttle Program. The first chapter covers observations on documentation quality and research challenges encountered during the Space Shuttle and Orion programs. The second chapter covers the knowledge capture approach used to create many of the reports covered in this document. These chapters are intended to provide future flight programs with insight that could be used to formulate knowledge capture and management strategies. The following chapters contain descriptions of each knowledge capture report. The majority of the reports concern the Space Shuttle. Three are included that were written in support of the Orion Program. Most of the reports were written from the years 2001 to 2011. Lessons learned reports concern primarily the shuttle Global Positioning System (GPS) upgrade and the knowledge capture process. Experience reports on navigation and rendezvous provide examples of how challenges were overcome and how best practices were identified and applied. Some reports are of a more technical history nature covering navigation and rendezvous. They provide an overview of mission activities and the evolution of operations concepts and trajectory design. The lessons learned, experience, and history reports would be considered secondary sources by historians and archivists.

AggieSat: Autonomous Rendezvous and Docking Technology Demonstrator, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Current autonomous rendezvous and docking (AR&D) capability in low Earth orbit (LEO) is constrained by sensor and effector mass, power, and accuracy limits. To...

Optimization of Spacecraft Rendezvous and Docking using Interval Analysis

NARCIS (Netherlands)

Van Kampen, E.; Chu, Q.P.; Mulder, J.A.

2010-01-01

This paper applies interval optimization to the fixed-time multiple impulse rendezvous and docking problem. Current methods for solving this type of optimization problem include for example genetic algorithms and gradient based optimization. Unlike these methods, interval methods can guarantee that

The factors influencing the decision making of operative treatment for proximal humeral fractures.

Science.gov (United States)

Hageman, Michiel G J S; Jayakumar, Prakash; King, John D; Guitton, Thierry G; Doornberg, Job N; Ring, David

2015-01-01

The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information. Secondarily, we addressed (1) factors associated with a recommendation for operative treatment, (2) factors associated with recommendation for arthroplasty, (3) concordance with the recommendations of the treating surgeons, and (4) factors affecting the inter-rater reliability of treatment recommendations. A total of 238 surgeons of the Science of Variation Group rated 40 radiographs of patients with proximal humerus fractures. Participants were randomized to receive information about the patient and mechanism of injury. The response variables included the choice of treatment (operative vs nonoperative) and the percentage of matches with the actual treatment. Participants who received patient information recommended operative treatment less than those who received no information. The patient information that had the greatest influence on treatment recommendations included age (55%) and fracture mechanism (32%). The only other factor associated with a recommendation for operative treatment was region of practice. There was no significant difference between participants who were and were not provided with information regarding agreement with the actual treatment (operative vs nonoperative) provided by the treating surgeon. Patient information-older age in particular-is associated with a higher likelihood of recommending nonoperative treatment than radiographs alone. Clinical information did not improve agreement of the Science of Variation Group with the actual treatment or the generally poor interobserver agreement on treatment recommendations. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Optical devices for proximity operations study and test report. [intensifying images for visual observation during space transportation system activities

Science.gov (United States)

Smith, R. A.

1979-01-01

Operational and physical requirements were investigated for a low-light-level viewing device to be used as a window-mounted optical sight for crew use in the pointing, navigating, stationkeeping, and docking of space vehicles to support space station operations and the assembly of large structures in space. A suitable prototype, obtained from a commercial vendor, was subjected to limited tests to determine the potential effectiveness of a proximity optical device in spacecraft operations. The constructional features of the device are discussed as well as concepts for its use. Tests results show that a proximity optical device is capable of performing low-light-level viewing services and will enhance manned spacecraft operations.

Development of a hardware-in-the-loop testbed to demonstrate multiple spacecraft operations in proximity

Science.gov (United States)

Eun, Youngho; Park, Sang-Young; Kim, Geuk-Nam

2018-06-01

This paper presents a new state-of-the-art ground-based hardware-in-the-loop test facility, which was developed to verify and demonstrate autonomous guidance, navigation, and control algorithms for space proximity operations and formation flying maneuvers. The test facility consists of two complete spaceflight simulators, an aluminum-based operational arena, and a set of infrared motion tracking cameras; thus, the testbed is capable of representing space activities under circumstances prevailing on the ground. The spaceflight simulators have a maximum of five-degree-of-freedom in a quasi-momentum-free environment, which is produced by a set of linear/hemispherical air-bearings and a horizontally leveled operational arena. The tracking system measures the real-time three-dimensional position and attitude to provide state variables to the agents. The design of the testbed is illustrated in detail for every element throughout the paper. The practical hardware characteristics of the active/passive measurement units and internal actuators are identified in detail from various perspectives. These experimental results support the successful development of the entire facility and enable us to implement and verify the spacecraft proximity operation strategy in the near future.

A preliminary clinical trial using flowable glass-ionomer cement as a liner in proximal-ART restorations: the operator effect

NARCIS (Netherlands)

Bonifácio, C.C.; Hesse, D.; Bönecker, M.; van Loveren, C.; van Amerongen, W.E.; Raggio, D.P.

2013-01-01

.Objectives: This in vivo study was carried out to assess the influence of the operator experience on the survival rate of proximal-ART restorations using a two-layer technique to insert the glass-ionomer cement (GIC). Study Design: Forty five proximal cavities in primary molars were restored in a

EUS-guided biliary drainage by using a standardized approach for malignant biliary obstruction: rendezvous versus direct transluminal techniques (with videos).

Science.gov (United States)

Khashab, Mouen A; Valeshabad, Ali Kord; Modayil, Rani; Widmer, Jessica; Saxena, Payal; Idrees, Mehak; Iqbal, Shahzad; Kalloo, Anthony N; Stavropoulos, Stavros N

2013-11-01

EUS-guided biliary drainage (EGBD) can be performed via direct transluminal or rendezvous techniques. It is unknown how both techniques compare in terms of efficacy and adverse events. To describe outcomes of EGBD performed by using a standardized approach and compare outcomes of rendezvous and transluminal techniques. Retrospective analysis of prospectively collected data. Two tertiary-care centers. Consecutive jaundiced patients with distal malignant biliary obstruction who underwent EGBD after failed ERCP between July 2006 and December 2012 were included. EGBD by using a standardized algorithm. Technical success, clinical success, and adverse events. During the study period, 35 patients underwent EGBD (rendezvous n = 13, transluminal n = 20). Technical success was achieved in 33 patients (94%), and clinical success was attained in 32 of 33 patients (97.0%). The mean postprocedure bilirubin level was 1.38 mg/dL in the rendezvous group and 1.33 mg/dL in the transluminal group (P = .88). Similarly, length of hospital stay was not different between groups (P = .23). There was no significant difference in adverse event rate between rendezvous and transluminal groups (15.4% vs 10%; P = .64). Long-term outcomes were comparable between groups, with 1 stent migration in the rendezvous group at 62 days and 1 stent occlusion in the transluminal group at 42 days after EGBD. Retrospective analysis, small number of patients, and selection bias. EGBD is safe and effective when the described standardized approach is used. Stent occlusion is not common during long-term follow-up. Both rendezvous and direct transluminal techniques seem to be equally effective and safe. The latter approach is a reasonable alternative to rendezvous EGBD. Copyright © 2013. Published by Mosby, Inc.

Analysis for orbital rendezvous of Chang'E-5 using SBI technique

Science.gov (United States)

Huang, Y.; Shan, Q.; Li, P.

2016-12-01

Chang'E-5 will be launched in later 2017/early 2018 using a new generation rocket from Wenchang satellite launch center, Hainan, China. It is a lunar sampling return mission, and it is the first time for China to carry out orbital rendezvous and docking in the Moon. How to achieve orbital rendezvous successfully in the Moon is very important in Chang'E-5 mission. Orbital rendezvous will be implemented between an orbiter and an ascender 200 km above the Moon. The ground tracking techniques include range, Doppler and VLBI, and they will be used to track the orbiter and the ascender when the ascender is about 70 km farther away from the orbiter. Later the ascender will approach the orbiter automatically. As a successful example, in Chang'E-3, the differential phase delay (delta delay) data between the rover and the lander are obtained with a random error of about 1 ps, and the relative position of the rover is determined with an accuracy of several meters by using same beam VLBI (SBI) technique. Here the application of the SBI technique for Chang'E-5 orbital rendezvous is discussed. SBI technique can be used to track the orbiter and the ascender simultaneously when they are in the same beam. Delta delay of the two probes can be derived, and the measurement accuracy is much higher than that of the traditional VLBI data because of the cancelation of common errors. Theoretically it can result in a more accurate relative orbit between the two probes. In the simulation, different strategies are discussed to analyze the contribution of SBI data to the orbit accuracy improvement especially relative orbit between the orbiter and ascender. The simulation results show that the relative position accuracy of the orbiter and ascender can reach about 1 m with delta delay data of 10 ps.

Robust H ∞ Control for Spacecraft Rendezvous with a Noncooperative Target

Science.gov (United States)

Wu, Shu-Nan; Zhou, Wen-Ya; Tan, Shu-Jun; Wu, Guo-Qiang

2013-01-01

The robust H ∞ control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H ∞ performance and finite time performance are proposed, and a robust H ∞ controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller. PMID:24027446

Orbit Determination for a Microsatellite Rendezvous with a Non-Cooperative Target

National Research Council Canada - National Science Library

Foster, Brian

2003-01-01

This study investigated the minimum requirements to establish a satellite tracking system architecture for a hostile "parasitic microsatellite" to rendezvous with a larger, non-cooperative target satellite...

Cooperative Rendezvous and Docking for Underwater Robots Using Model Predictive Control and Dual Decomposition

DEFF Research Database (Denmark)

Nielsen, Mikkel Cornelius; Johansen, Tor Arne; Blanke, Mogens

2018-01-01

This paper considers the problem of rendezvous and docking with visual constraints in the context of underwater robots with camera-based navigation. The objective is the convergence of the vehicles to a common point while maintaining visual contact. The proposed solution includes the design of a ...... of a distributed model predictive controller based on dual decomposition, which allows for optimization in a decentralized fashion. The proposed distributed controller enables rendezvous and docking between vehicles while maintaining visual contact....

Ternary and hybrid controllers for the rendezvous of unicycles

NARCIS (Netherlands)

Jafarian, Matin

2015-01-01

This paper presents the rendezvous (consensus) of the orientations and average positions of a group of unicycles. We assume that the decentralized controllers designed for consensus of the average positions take only values in the set {-1; 0; +1}. In addition, we introduce a hybrid controller to

Trajectory design for a rendezvous mission to Earth's Trojan asteroid 2010 TK7

Science.gov (United States)

Lei, Hanlun; Xu, Bo; Zhang, Lei

2017-12-01

In this paper a rendezvous mission to the Earth's Trojan asteroid 2010 TK7 is proposed, and preliminary transfer trajectories are designed. Due to the high inclination (∼ 20.9°) of the target asteroid relative to the ecliptic plane, direct transfers usually require large amounts of fuel consumption, which is beyond the capacity of current technology. As gravity assist technique could effectively change the inclination of spacecraft's trajectory, it is adopted to reduce the launch energy and rendezvous velocity maneuver. In practical computation, impulsive and low-thrust, gravity-assisted trajectories are considered. Among all the trajectories computed, the low-thrust gravity-assisted trajectory with Venus-Earth-Venus (V-E-V) swingby sequence performs the best in terms of propellant mass. For a spacecraft with initial mass of 800 kg , propellant mass of the best trajectory is 36.74 kg . Numerical results indicate that both the impulsive and low-thrust, gravity-assisted trajectories corresponding to V-E-V sequence could satisfy mission constraints, and can be applied to practical rendezvous mission.

Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation

Science.gov (United States)

Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.

1995-01-01

Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be

Percutaneous-endoscopic rendezvous procedure for the management of bile duct injuries after cholecystectomy: short- and long-term outcomes

NARCIS (Netherlands)

Schreuder, Anne Marthe; Booij, Klaske A. C.; de Reuver, Philip R.; van Delden, Otto M.; van Lienden, Krijn P.; Besselink, Marc G.; Busch, Olivier R.; Gouma, Dirk J.; Rauws, Erik A. J.; van Gulik, Thomas M.

2018-01-01

Bile duct injury (BDI) remains a daunting complication of laparoscopic cholecystectomy. In patients with complex BDI, a percutaneous-endoscopic rendezvous procedure may be required to establish bile duct continuity. The aim of this study was to assess short- and long-term outcomes of the rendezvous

The comet rendezvous asteroid flyby mission

International Nuclear Information System (INIS)

Morrison, D.; Neugebauer, M.; Weissman, P.R.

1989-01-01

The Comet Rendezvous Asteroid Flyby (CRAF) mission is designed to answer the many questions raised by the Halley missions by exploring a cometary nucleus in detail, following it around its orbit and studying its changing activity as it moves closer to and then away from the Sun. In addition, on its way to rendezvous with the comet, CRAF will fly by a large, primitive class main belt asteroid and will return valuable data for comparison with the comet results. The selected asteroid is 449 Hamburga with a diameter of 88 km and a surface composition of carbonaceous chondrite meteorites. The expected flyby date is January, 1998. The CRAF spacecraft will continue to make measurements in orbit around the cometary nucleus as they both move closer to the Sun, until the dust and gas hazard becomes unsafe. At that point the spacecraft will move in and out between 50 and 2,500 kilometers to study the inner coma and the cometary ionosphere, and to collect dust and gas samples for onboard analysis. Following perihelion, the spacecraft will make a 50,000 km excursion down the comet's tail, further investigating the solar wind interaction with the cometary atmosphere. The spacecraft will return to the vicinity of the nucleus about four months after perihelion to observe the changes that have taken place. If the spacecraft remains healthy and adequate fuel is still onboard, an extended mission to follow the comet nucleus out to aphelion is anticipated

Endoskopisk ultralydvejledt rendezvous til intern drænage ved galdevejsobstruktion

DEFF Research Database (Denmark)

Knudsen, Marie Høxbro; Vilmann, Peter; Hassan, Hazem

2015-01-01

Endoscopic retrograde cholangiography (ERCP) is currently standard treatment for biliary drainage. Endoscopic ultrasound guided rendezvous (EUS-RV) is a novel method to overcome an unsuccessful biliary drainage procedure. Under endoscopic ultrasound guidance a guidewire is passed via a needle from...

[Ureteral realignment with the rendezvous procedure in complex ureteral injuries - aspects of technique and our experience].

Science.gov (United States)

Brandt, Alexander Sascha; von Rundstedt, F-C; Lazica, D A; Roth, S

2010-07-01

The rendezvous procedure for re-establishing ureteral continuity after complex ureteral injuries is introduced and we present our experience with this technique. Aspects of the technique are described in a detailed step-by-step instruction using intraoperative radiographs. We evaluated our patient data from 1998 until 2009 for cases in which the rendezvous procedure was attempted. The rendezvous procedure was used in a total of 11 patients. Realignment was successful in 10 cases (90.9 %) and the initial nephrostomy could be removed. In 3 of 7 cases postoperative removal of the JJ ureteric stent was successful. In 7 patients the final surgical ureter reconstruction was performed after a medium period of 7 months. 5 cases of ureteroneocystostomy and 2 cases of reconstruction of the ureter either with colon or ileum segments were accomplished. In 1 patient a permanent maintenance of the DJ ureteral stent was necessary. Ureteral realignment with the rendezvous procedure enables disposition of the ureteral stent in many cases, exclusively antegrade or retrograde procedures failed. By this means nephrostomy could be spared as a temporary or permanent solution and a better chance of restitutio ad integrum could be realised. Georg Thieme Verlag KG Stuttgart * New York.

Optimal planning approaches with multiple impulses for rendezvous based on hybrid genetic algorithm and control method

Directory of Open Access Journals (Sweden)

JingRui Zhang

2015-03-01

Full Text Available In this article, we focus on safe and effective completion of a rendezvous and docking task by looking at planning approaches and control with fuel-optimal rendezvous for a target spacecraft running on a near-circular reference orbit. A variety of existent practical path constraints are considered, including the constraints of field of view, impulses, and passive safety. A rendezvous approach is calculated by using a hybrid genetic algorithm with those constraints. Furthermore, a control method of trajectory tracking is adopted to overcome the external disturbances. Based on Clohessy–Wiltshire equations, we first construct the mathematical model of optimal planning approaches of multiple impulses with path constraints. Second, we introduce the principle of hybrid genetic algorithm with both stronger global searching ability and local searching ability. We additionally explain the application of this algorithm in the problem of trajectory planning. Then, we give three-impulse simulation examples to acquire an optimal rendezvous trajectory with the path constraints presented in this article. The effectiveness and applicability of the tracking control method are verified with the optimal trajectory above as control objective through the numerical simulation.

Rendezvous technique for recanalization of long-segmental chronic total occlusion above the knee following unsuccessful standard angioplasty.

Science.gov (United States)

Cao, Jun; Lu, Hai-Tao; Wei, Li-Ming; Zhao, Jun-Gong; Zhu, Yue-Qi

2016-04-01

To assess the technical feasibility and efficacy of the rendezvous technique, a type of subintimal retrograde wiring, for the treatment of long-segmental chronic total occlusions above the knee following unsuccessful standard angioplasty. The rendezvous technique was attempted in eight limbs of eight patients with chronic total occlusions above the knee after standard angioplasty failed. The clinical symptoms and ankle-brachial index were compared before and after the procedure. At follow-up, pain relief, wound healing, limb salvage, and the presence of restenosis of the target vessels were evaluated. The rendezvous technique was performed successfully in seven patients (87.5%) and failed in one patient (12.5%). Foot pain improved in all seven patients who underwent successful treatment, with ankle-brachial indexes improving from 0.23 ± 0.13 before to 0.71 ± 0.09 after the procedure (P rendezvous technique is a feasible and effective treatment for chronic total occlusions above the knee when standard angioplasty fails. © The Author(s) 2015.

A 10-year study of rendezvous intraoperative endoscopic retrograde cholangiography during cholecystectomy and the risk of post-ERCP pancreatitis.

Science.gov (United States)

Noel, Rozh; Enochsson, Lars; Swahn, Fredrik; Löhr, Matthias; Nilsson, Magnus; Permert, Johan; Arnelo, Urban

2013-07-01

Rendezvous intraoperative endoscopic retrograde cholangiography (RV-IOERC), also called guidewire-facilitated IOERC, is one of the single-stage options available for managing common bile duct stones (CBDS) during laparoscopic cholecystectomy. The objective of this study is to investigate procedure-related complications in IOERC patients and stone clearance. All patients who underwent IOERC between January 2000 and December 2009 were identified from the local registry of Karolinska University Hospital in Huddinge. Medical charts and ERC reports were studied, and descriptive statistics were obtained. Outcomes were procedure-related complications, especially post-ERCP pancreatitis (PEP), stone clearance, and mortality. 307 patients were identified. In 264 of the patients, the rendezvous cannulation technique was successful (86 %); in the remaining 43 patients, conventional cannulation technique was necessary. In total, PEP occurred in seven patients (2.28 %). One of the PEP patients was in the rendezvous cannulated group (0.37 %), whereas six patients developed PEP in the nonrendezvous group (13.95 %, p < 0.001). The primary stone clearance rate was 88.27 % (271/307). There was no mortality within 90 days in the series. IOERC with RV cannulation technique for management of CBDS during laparoscopic cholecystectomy has a low PEP rate and a high stone clearance rate, making it a safe and feasible method for removing CBDS. However, the technique requires logistics to perform IOERC in the operating theater. The present data suggest that IOERC with RV cannulation is superior to conventional cannulation with respect to risk of PEP.

A "rendezvous technique" for treating a pancreatic fistula after distal pancreatectomy.

Science.gov (United States)

Imai, Daisuke; Yamashita, Yo-ichi; Ikegami, Toru; Toshima, Takeo; Harimoto, Norifumi; Yoshizumi, Tomoharu; Soejima, Yuji; Shirabe, Ken; Ikeda, Tetsuo; Maehara, Yoshihiko

2015-01-01

Pancreatic fistulae are a major complication of distal pancreatectomy (DP). Some cases of severe pancreatic fistula require invasive procedures. There have been some reports concerning the effectiveness of pancreatic duct drainage through an endoscopic transpapillary approach for pancreatic fistulae. We herein present a case of a pancreatic fistula after DP that was successfully treated with percutaneous pancreatic duct drainage, which was performed using a combined percutaneous and endoscopic approach, named the "rendezvous technique". In our case, we performed distal pancreatectomy with celiac artery resection for a locally advanced pancreatic body cancer. On postoperative day (POD) 7, the drain amylase level increased up to 37,460 IU/l. Computed tomography (CT) revealed peripancreatic fluid collections. On POD 10, we placed a catheter in the main pancreatic duct using the rendezvous technique. CT on POD 14 revealed a decrease in the size of the peripancreatic fluid collection, and contrast imaging from the drains on POD 22 revealed almost complete disappearance of the fluid collection. We withdrew the pigtail catheter on POD 27 and the percutaneous pancreatic duct drain on POD 36. This patient was discharged from our hospital on POD 40. We herein report a new approach called the "rendezvous technique" for the management of pancreatic fistulae after DP that can be used instead of a stressful nasopancreatic tube.

"Rendezvous technique" for intraluminal vacuum therapy of anastomotic leakage of the jejunum.

Science.gov (United States)

Krajinovic, K; Reimer, S; Kudlich, T; Germer, C T; Wiegering, A

2016-12-01

Anastomotic leakage (AL) is one of the most common and serious complications following visceral surgery. In recent years, endoluminal vacuum therapy has dramatically changed therapeutic options for AL, but its use has been limited to areas easily accessible by endoscope. We describe the first use of endoluminal vacuum therapy in the small intestine employing a combined surgical and endoscopic "rendezvous technique" in which the surgeon assists the endoscopic placement of an endoluminal vacuum therapy sponge in the jejunum by means of a pullback string. This technique led to a completely closed AL after 27 days and 7 changes of the endosponge. The combined surgical and endoscopic rendezvous technique can be useful in cases of otherwise difficult endosponge placement.

Choledocholithiasis and endo-laparoscopic rendezvous. Analysis of 59 consecutive cases.

Science.gov (United States)

Del Rio, Paolo; Dell'Abate, Paolo; Labonia, Domenico; Negri, Marco; Sianesi, Nicoletta; Arcuri, Maria Francesca; Sianesi, Mario

2011-01-01

Choledocholithiasis is a real problem of major clinical importance. The incidence of cholelithiasis is 10-20%. We have examined 2907 patients treated with videolaparoscopic cholecystectomy (VLC) between January 2001 and September 2009. 214 cases (7.4%) were affected by choledocolithiasis; among these, 59 consecutive cases were treated by rendezvous, 151 cases by sequential treatment (ERCP-ES before VLC), 3 cases by extraction with Dormia's basket, and 1 case by ERCP-ES after VLC. The complications were one biliary fistula and three hemorrhages (one from the cystic artery, one from the hepatic area and one from trocar's site). The mean hospital stay was 1.38 +/- 0.83 days for the rendezvous group vs 4 53 +/- 0.74 days in the sequential treatment group (prendezvous procedure reduces hospital stay and has a greater compliance (only one treatment). We can use this option in the management of cases where preoperative ERCP-ES has failed.

[Endoscopic ultrasound guided rendezvous for biliary drainage].

Science.gov (United States)

Knudsen, Marie Høxbro; Vilmann, Peter; Hassan, Hazem; Karstensen, John Gésdal

2015-04-27

Endoscopic retrograde cholangiography (ERCP) is currently standard treatment for biliary drainage. Endoscopic ultrasound guided rendezvous (EUS-RV) is a novel method to overcome an unsuccessful biliary drainage procedure. Under endoscopic ultrasound guidance a guidewire is passed via a needle from the stomach or duodenum to the common bile duct and from there on to the duodenum enabling ERCP. With a relatively high rate of success EUS-RV should be considered as an alternative to biliary drainage and surgical intervention.

Autonomous Mars ascent and orbit rendezvous for earth return missions

Science.gov (United States)

Edwards, H. C.; Balmanno, W. F.; Cruz, Manuel I.; Ilgen, Marc R.

1991-01-01

The details of tha assessment of autonomous Mars ascent and orbit rendezvous for earth return missions are presented. Analyses addressing navigation system assessments, trajectory planning, targeting approaches, flight control guidance strategies, and performance sensitivities are included. Tradeoffs in the analysis and design process are discussed.

Stricture location predicts swallowing outcomes following endoscopic rendezvous procedures.

Science.gov (United States)

Adams, Katherine N; Shah, Rupali N; Buckmire, Robert A

2017-06-01

Complete pharyngoesophageal strictures may be encountered by the otolaryngologist as a consequence of radiation/chemoradiotherapy therapies for head and neck cancer. A combined anterograde and retrograde dilation procedure (rendezvous procedure) has proven to be a useful surgical intervention in these cases. We assess the long-term swallowing outcomes of this patient cohort including gastrostomy tube (G-tube) reliance, swallowing quality of life, and variables that contribute to improved swallowing outcomes. Retrospective chart review. A retrospective chart review of 18 consecutive patients treated with rendezvous procedures between April 2007 and May 2015 was carried out. Data were collected from chart review and follow-up telephone calls including demographics, surgical/postoperative course details, and Eating Assessment Tool (EAT-10) (swallowing quality of life) scores. The completion rate of the procedure was 83% (15 completed/3 procedures aborted). Average follow-up was 22 months. Thirteen of 15 (86.7%) achieved an oral diet, and 7/15 (46.7%) had their G-tube removed. G-tube-independent (GTI) patients had an average stricture length of 2.33 cm and an average distance from the incisors of 17.4 cm compared to G-tube dependent-(GTD) patients who had an average stricture length of 2.63 cm and 14.6 cm mean distance from the incisors (P = .66 and .0343, respectively). Final EAT-10 scores averaged 20.1 in GTI patients and 33.8 in GTD patients (P = .022). Stricture/incisor distance and EAT-10 scores demonstrated a moderate to strong negative correlation (r = -0.67). Following the endoscopic rendezvous procedure, swallowing outcomes and G-tube status is related to the distance of the stricture from the incisors. 2b Laryngoscope, 127:1388-1391, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

ProxImaL: efficient image optimization using proximal algorithms

KAUST Repository

Heide, Felix; Diamond, Steven; Nieß ner, Matthias; Ragan-Kelley, Jonathan; Heidrich, Wolfgang; Wetzstein, Gordon

2016-01-01

domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety

A Ground Testbed to Advance US Capability in Autonomous Rendezvous and Docking Project

Science.gov (United States)

D'Souza, Chris

2014-01-01

This project will advance the Autonomous Rendezvous and Docking (AR&D) GNC system by testing it on hardware, particularly in a flight processor, with a goal of testing it in IPAS with the Waypoint L2 AR&D scenario. The entire Agency supports development of a Commodity for Autonomous Rendezvous and Docking (CARD) as outlined in the Agency-wide Community of Practice whitepaper entitled: "A Strategy for the U.S. to Develop and Maintain a Mainstream Capability for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond". The whitepaper establishes that 1) the US is in a continual state of AR&D point-designs and therefore there is no US "off-the-shelf" AR&D capability in existence today, 2) the US has fallen behind our foreign counterparts particularly in the autonomy of AR&D systems, 3) development of an AR&D commodity is a national need that would benefit NASA, our commercial partners, and DoD, and 4) an initial estimate indicates that the development of a standardized AR&D capability could save the US approximately $60M for each AR&D project and cut each project's AR&D flight system implementation time in half.

Concurrent image-based visual servoing with adaptive zooming for non-cooperative rendezvous maneuvers

Science.gov (United States)

Pomares, Jorge; Felicetti, Leonard; Pérez, Javier; Emami, M. Reza

2018-02-01

An image-based servo controller for the guidance of a spacecraft during non-cooperative rendezvous is presented in this paper. The controller directly utilizes the visual features from image frames of a target spacecraft for computing both attitude and orbital maneuvers concurrently. The utilization of adaptive optics, such as zooming cameras, is also addressed through developing an invariant-image servo controller. The controller allows for performing rendezvous maneuvers independently from the adjustments of the camera focal length, improving the performance and versatility of maneuvers. The stability of the proposed control scheme is proven analytically in the invariant space, and its viability is explored through numerical simulations.

Apollo-Soyuz test project. Operations handbook command/service/docking modules (CSM 119/DM 1): Operational procedures reference issue

Science.gov (United States)

1974-01-01

Operational and configuration checks for the Apollo-Soyuz Test Project are presented. The checks include: backup crew prelaunch, prime crew prelaunch, boost and insertion, G and C reference data, G and N reference modes, rendezvous, navigation, Apollo-Soyuz operations, abort procedures, and emergency procedures.

Adaptive nonlinear robust relative pose control of spacecraft autonomous rendezvous and proximity operations.

Science.gov (United States)

Sun, Liang; Huo, Wei; Jiao, Zongxia

2017-03-01

This paper studies relative pose control for a rigid spacecraft with parametric uncertainties approaching to an unknown tumbling target in disturbed space environment. State feedback controllers for relative translation and relative rotation are designed in an adaptive nonlinear robust control framework. The element-wise and norm-wise adaptive laws are utilized to compensate the parametric uncertainties of chaser and target spacecraft, respectively. External disturbances acting on two spacecraft are treated as a lumped and bounded perturbation input for system. To achieve the prescribed disturbance attenuation performance index, feedback gains of controllers are designed by solving linear matrix inequality problems so that lumped disturbance attenuation with respect to the controlled output is ensured in the L 2 -gain sense. Moreover, in the absence of lumped disturbance input, asymptotical convergence of relative pose are proved by using the Lyapunov method. Numerical simulations are performed to show that position tracking and attitude synchronization are accomplished in spite of the presence of couplings and uncertainties. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Hybrid Proximal-Point Methods for Zeros of Maximal Monotone Operators, Variational Inequalities and Mixed Equilibrium Problems

Directory of Open Access Journals (Sweden)

Kriengsak Wattanawitoon

2011-01-01

Full Text Available We prove strong and weak convergence theorems of modified hybrid proximal-point algorithms for finding a common element of the zero point of a maximal monotone operator, the set of solutions of equilibrium problems, and the set of solution of the variational inequality operators of an inverse strongly monotone in a Banach space under different conditions. Moreover, applications to complementarity problems are given. Our results modify and improve the recently announced ones by Li and Song (2008 and many authors.

Implications of Articulating Machinery on Operator Line of Sight and Efficacy of Camera Based Proximity Detection Systems

Directory of Open Access Journals (Sweden)

Nicholas Schwabe

2017-07-01

Full Text Available The underground mining industry, and some above ground operations, rely on the use of heavy equipment that articulates to navigate corners in the tight confines of the tunnels. Poor line of sight (LOS has been identified as a problem for safe operation of this machinery. Proximity detection systems, such as a video system designed to provide a 360 degree view around the machine have been implemented to improve the available LOS for the operator. A four-camera system was modeled in a computer environment to assess LOS on a 3D cad model of a typical, articulated machine. When positioned without any articulation, the system is excellent at removing blind spots for a machine driving straight forward or backward in a straight tunnel. Further analysis reveals that when the machine articulates in a simulated corner section, some camera locations are no longer useful for improving LOS into the corner. In some cases, the operator has a superior view into the corner, when compared to the best available view from the camera. The work points to the need to integrate proximity detection systems at the design, build, and manufacture stage, and to consider proper policy and procedures that would address the gains and limits of the systems prior to implementation.

DART AVGS Performance

Science.gov (United States)

Howard, Richard T.; Bryan, Thomas C.

2007-01-01

The Advanced Video Guidance Sensor (AVGS) was designed to be the proximity operations sensor for the Demonstration of Autonomous Rendezvous Technologies (DART). The DART mission flew in April of2005 and was a partial success. The AVGS did not get the opportunity to operate in every mode in orbit, but those modes in which it did operate were completely successful. This paper will detail the development, testing, and on-orbit performance of the AVGS.

Resolving external pancreatic fistulas in patients with disconnected pancreatic duct syndrome: using rendezvous techniques to avoid surgery (with video).

Science.gov (United States)

Irani, Shayan; Gluck, Michael; Ross, Andrew; Gan, S Ian; Crane, Robert; Brandabur, John J; Hauptmann, Ellen; Fotoohi, Mehran; Kozarek, Richard A

2012-09-01

An external pancreatic fistula (EPF) generally results from an iatrogenic manipulation of a pancreatic fluid collection (PFC), such as walled-off pancreatic necrosis (WOPN). Severe necrotizing pancreatitis can lead to complete duct disruption, causing disconnected pancreatic duct syndrome (DPDS) with viable upstream pancreas draining out of a low-pressure fistula created surgically or by a percutaneous catheter. The EPF can persist for months to years, and distal pancreatectomy, often the only permanent solution, carries a high morbidity and defined mortality. To describe 3 endoscopic and percutaneous rendezvous techniques to completely resolve EPFs in the setting of DPDS. A retrospective review of a prospective database of 15 patients who underwent rendezvous internalization of EPFs. Tertiary-care pancreatic referral center. Fifteen patients between October 2002 and October 2011 with EPFs in the setting of DPDS and resolved WOPN. Three rendezvous techniques that combined endoscopic and percutaneous procedures to internalize EPFs by transgastric, transduodenal, or transpapillary methods. EPF resolution and morbidity. Fifteen patients (12 men) with a median age of 51 years (range 24-65 years) with EPFs and DPDS (cutoff/blowout of pancreatic duct, with inability to demonstrate upstream body/tail of pancreas on pancreatogram) resulting from severe necrotizing pancreatitis underwent 1 of 3 rendezvous procedures to eliminate the EPFs. All patients were either poor surgical candidates or refused surgery. At the time of the rendezvous procedure, WOPN had fully resolved, DPDS was confirmed on pancreatography, and the EPF had persisted for a median of 5 months (range 1-48 months), producing a median output of 200 mL/day (range 50-700 mL/day). The rendezvous technique in 10 patients used the existing percutaneous drainage fistula to puncture into the stomach/duodenum to deliver wires that were captured endoscopically. The transenteric fistula was dilated and two

Usefulness of the rendezvous technique for biliary stricture after adult right-lobe living-donor liver transplantation with duct-to-duct anastomosis.

Science.gov (United States)

Chang, Jae Hyuck; Lee, In Seok; Chun, Ho Jong; Choi, Jong Young; Yoon, Seung Kyoo; Kim, Dong Goo; You, Young Kyoung; Choi, Myung-Gyu; Choi, Kyu-Yong; Chung, In-Sik

2010-03-01

Replacement of a percutaneous transhepatic biliary drainage (PTBD) catheter with inside stents using endoscopic retrograde cholangiography is difficult in patients with angulated or twisted biliary anastomotic stricture after living donor liver transplantation (LDLT). We evaluated the usefulness and safety of the rendezvous technique for the management of biliary stricture after LDLT. Twenty patients with PTBD because of biliary stricture after LDLT with duct-to-duct anastomosis underwent the placement of inside stents using the rendezvous technique. Inside stents were successfully placed in the 20 patients using the rendezvous technique. The median procedure time was 29.6 (range, 7.5-71.8) minutes. The number of inside stents placed was one in 12 patients and two in eight patients. One mild acute pancreatitis and one acute cholangitis occurred, which improved within a few days. Inside stent related sludge or stone was identified in 12 patients during follow-up. Thirteen patients achieved stent-free status for a median of 281 (range, 70-1,351) days after removal of the inside stents. The rendezvous technique is a useful and safe method for the replacement of PTBD catheter with inside stent in patients with biliary stricture after LDLT with duct-to-duct anastomosis. The rendezvous technique could be recommended to patients with angulated or twisted strictures.

Spacecraft Rendezvous Guidance in Cluttered Dynamical Environments via Extreme Learning Machines, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — DeepAnalytX, Inc. proposes to investigate a new approach to perform real-time, closed-loop optimal and robust rendezvous guidance in space environments comprising a...

Current status of laparoendoscopic rendezvous in the treatment of cholelithiasis with concomitant choledocholithiasis.

Science.gov (United States)

Baloyiannis, Ioannis; Tzovaras, George

2015-06-25

The current evidence in favor of the laparoendoscopic rendezvous is promising and demonstrates the main advantages of this technique in regard to shorter hospital stay and selective cannulation of the common bile duct (CBD), avoiding thus the inadvertent cannulation of the pancreatic duct. In addition, in the rendezvous technique the contrast medium is not injected retrogradely as during the traditional endoscopic retrograde cholangiopancreatography (ERCP), when the medium accidentally could be injected under pressure into the pancreatic duct. The RV technique minimizes that risk. Both these main advantages of the RV technique over the classic ERCP, are related with a significant lower incidence of hyperamylasemia and post-ERCP pancreatitis, compared with the traditional two stage procedure. Choledocholithiasis is present in 10% to 15% of patients undergoing cholecystectomy. To date, the ideal management of CBD stones remains controversial. Prospective randomized trials have shown that laparoscopic management of the CBD stones, as a single stage procedure, is the most efficient and cost effective method of treatment. Laparoendoscopic rendezvous has been proposed as an alternative single stage approach. Several studies have shown the effective use of this technique in the treatment of CBD stones by improving patient compliance and clinical results including shorter hospital stay, higher success rate and less cost. The current evidence about the use of this technique presented in this review article is promising and demonstrates the main advantages of the procedure.

Operative management of partial-thickness tears of the proximal hamstring muscles in athletes.

Science.gov (United States)

Bowman, Karl F; Cohen, Steven B; Bradley, James P

2013-06-01

Partial tears of the hamstring muscle origin represent a challenging clinical problem to the patient and orthopaedic surgeon. Although nonoperative treatment is frequently met with limited success, there is a paucity of data on the efficacy of surgical management for partial proximal hamstring tears in the active and athletic population. To evaluate the results of an anatomic repair for partial tears of the hamstring muscle origin in athletes. Case series; Level of evidence, 4. The records of 17 patients with partial tears of the proximal hamstring origin were reviewed after institutional review board approval was obtained. All patients were treated with open debridement and primary tendon repair after failure of at least 6 months of nonoperative therapy. Clinical and operative records, radiographs, and magnetic resonance images were reviewed for all patients. A patient-reported outcomes survey was completed by 14 patients that included the Lower Extremity Functional Score (LEFS), Marx activity rating scale, custom LEFS and Marx scales, and subjective patient satisfaction scores. Early and late postoperative complications were recorded. There were 3 male and 14 female patients; their average age was 43 years (range, 19-64 years) and average follow-up was 32 months (range, 12-51 months). There were 2 collegiate athletes (field hockey, track), 14 amateur athletes (distance running, waterskiing, tennis), and a professional bodybuilder. Postoperative LEFS was 73.3 ± 9.9 (range, 50-80) and custom LEFS was 66.7 ± 17.0 (range, 37-80) of a maximum 80 points. The most commonly reported difficulty was with prolonged sitting and explosive direction change while running. The average Marx score was 6.5 ± 5.3 (range, 0-16) of a maximum 16, correlating with a greater return to recreational running activities in this patient cohort than regular participation in pivoting or cutting sports. Marx custom scores were 20 of a maximum 20 in all patients, demonstrating no disability in

Integrated vision-based GNC for autonomous rendezvous and capture around Mars

Science.gov (United States)

Strippoli, L.; Novelli, G.; Gil Fernandez, J.; Colmenarejo, P.; Le Peuvedic, C.; Lanza, P.; Ankersen, F.

2015-06-01

Integrated GNC (iGNC) is an activity aimed at designing, developing and validating the GNC for autonomously performing the rendezvous and capture phase of the Mars sample return mission as defined during the Mars sample return Orbiter (MSRO) ESA study. The validation cycle includes testing in an end-to-end simulator, in a real-time avionics-representative test bench and, finally, in a dynamic HW in the loop test bench for assessing the feasibility, performances and figure of merits of the baseline approach defined during the MSRO study, for both nominal and contingency scenarios. The on-board software (OBSW) is tailored to work with the sensors, actuators and orbits baseline proposed in MSRO. The whole rendezvous is based on optical navigation, aided by RF-Doppler during the search and first orbit determination of the orbiting sample. The simulated rendezvous phase includes also the non-linear orbit synchronization, based on a dedicated non-linear guidance algorithm robust to Mars ascent vehicle (MAV) injection accuracy or MAV failures resulting in elliptic target orbits. The search phase is very demanding for the image processing (IP) due to the very high visual magnitude of the target wrt. the stellar background, and the attitude GNC requires very high pointing stability accuracies to fulfil IP constraints. A trade-off of innovative, autonomous navigation filters indicates the unscented Kalman filter (UKF) as the approach that provides the best results in terms of robustness, response to non-linearities and performances compatibly with computational load. At short range, an optimized IP based on a convex hull algorithm has been developed in order to guarantee LoS and range measurements from hundreds of metres to capture.

The mobile agent rendezvous problem in the ring

CERN Document Server

Kranakis, Evangelos; Marcou, Euripides

2010-01-01

Mobile agent computing is being used in fields as diverse as artificial intelligence, computational economics and robotics. Agents' ability to adapt dynamically and execute asynchronously and autonomously brings potential advantages in terms of fault-tolerance, flexibility and simplicity. This monograph focuses on studying mobile agents as modelled in distributed systems research and in particular within the framework of research performed in the distributed algorithms community. It studies the fundamental question of how to achieve rendezvous, the gathering of two or more agents at the same n

Proximity sensor system development. CRADA final report

Energy Technology Data Exchange (ETDEWEB)

Haley, D.C. [Oak Ridge National Lab., TN (United States); Pigoski, T.M. [Merrit Systems, Inc. (United States)

1998-01-01

Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors.

Proximity sensor system development. CRADA final report

International Nuclear Information System (INIS)

Haley, D.C.; Pigoski, T.M.

1998-01-01

Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors

Rendezvous terminal phase automatic braking sequencing and targeting. [for space shuttle orbiter

Science.gov (United States)

Kachmar, P. M.

1973-01-01

The purpose of the rendezvous terminal phase braking program is to provide the means of automatically bringing the primary orbiter within desired station keeping boundaries relative to the target satellite. A detailed discussion is presented on the braking program and its navigation, targeting, and guidance functions.

An Application of Linear Covariance Analysis to the Design of Responsive Near-Rendezvous Missions

National Research Council Canada - National Science Library

Visser, Benjamin L

2007-01-01

This thesis investigates a new class of launch vehicles capable of being released from an aircraft which ultimately have the goal of achieving near-rendezvous conditions at orbital altitudes up to 800 km...

Bimalleolar ankle fracture with proximal fibular fracture

NARCIS (Netherlands)

Colenbrander, R. J.; Struijs, P. A. A.; Ultee, J. M.

2005-01-01

A 56-year-old female patient suffered a bimalleolar ankle fracture with an additional proximal fibular fracture. This is an unusual fracture type, seldom reported in literature. It was operatively treated by open reduction and internal fixation of the lateral malleolar fracture. The proximal fibular

Leak or Fistula After Sleeve Gastrectomy: Treatment with Pigtail Drain by the Rendezvous Technique.

Science.gov (United States)

Soufron, Jacques

2015-10-01

After a sleeve gastrectomy, a leak or fistula is a serious complication. Laparoscopic drainage, drainage under US or CT scan control, or endoscopic insertion of a stent can be used, but a major re-operation is sometimes unavoidable. Endoscopic drainage with a pigtail catheter could give more success and fewer complications, but the insertion of the drain is not always possible nor does it always provide a perfect drainage. If a laparoscopic second look appears necessary, it is possible to insert a pigtail drain laparoscopically, but under endoscopic control, ensuring a correct positioning of the drain both in the peritoneal cavity and in the gastric tube. This simultaneous "rendezvous" technique could combine in this situation the advantages of purely surgical techniques and of purely endoscopic or image-guided techniques.

In-Flight Operation of the Dawn Ion Propulsion System: Status at One Year from the Vesta Rendezvous

Science.gov (United States)

Garner, Charles E.; Rayman, Marc D.

2010-01-01

, 2007 and was successfully concluded as planned on October 31, 2008. During this time period the Dawn IPS was operated mostly at full power for approximately 6500 hours, consumed 71.7 kg of xenon and delivered approximately 1.8 km/s of delta V to the spacecraft. The thrusting to Mars was followed by a coasting period of approximately 3.5 months that included a Mars flyby in February of 2009. The Mars flyby provided a gravity assist (MGA) for a plane change and approximately 1 km/s of heliocentric energy increase and is the only part of the mission following launch in which a needed velocity change is not accomplished by the IPS. During the coast period IPS was operated for a trajectory correction maneuver and for engineering tests but was not operated for primary propulsion. Closest approach to Mars occurred as planned on February 17, 2009 and was followed by another coasting period of just under 4 months in duration. During this last coasting phase IPS was operated only for routine maintenance activities and for system engineering tests. Deterministic thrusting for heliocentric transfer to Vesta resumed on June 8, 2009. Since resumption of cruise to Vesta IPS has been operated at throttled power levels, most of the time at full power, and with a duty cycle of approximately 93%, leading to an arrival at Vesta in July of 2011 and arrival at Ceres in February 2015. This paper provides an overview of Dawn's mission objectives and the results of Dawn IPS mission operations through one year from the spacecraft's rendezvous with Vesta.

A phase one AR/C system design

Science.gov (United States)

Kachmar, Peter M.; Polutchko, Robert J.; Matusky, Martin; Chu, William; Jackson, William; Montez, Moises

1991-01-01

The Phase One AR&C System Design integrates an evolutionary design based on the legacy of previous mission successes, flight tested components from manned Rendezvous and Proximity Operations (RPO) space programs, and additional AR&C components validated using proven methods. The Phase One system has a modular, open architecture with the standardized interfaces proposed for Space Station Freedom system architecture.

Rendezvous, un juego de Lewis Carroll

Directory of Open Access Journals (Sweden)

José Manuel Sánchez Muñoz

2011-10-01

Full Text Available Todos en mayor o menor medida asociamos el nombre de Lewis Carrolla la literatura, sobre todo a la de temática infantil, con títulos a sus espaldas como Alicia en el País de las Maravillas, Alicia a través del espejo, o La Caza del Snark. Pero además de literato, Lewis Carrol fue un hombre con bastantes inquietudes en torno a la matemática, la lógica y el pensamiento filosófico. Pero no todo el mundo es conocedor de su faceta como creativo en el campo de los juegos. Rendezvous es una de sus más sorprendentes invenciones,un juego de inteligencia para todos los públicos, cuyas directrices hacen de él un entretenimiento bastante original.

Satellite Servicing's Autonomous Rendezvous and Docking Testbed on the International Space Station

Science.gov (United States)

Naasz, Bo J.; Strube, Matthew; Van Eepoel, John; Barbee, Brent W.; Getzandanner, Kenneth M.

2011-01-01

The Space Servicing Capabilities Project (SSCP) at NASA's Goddard Space Flight Center (GSFC) has been tasked with developing systems for servicing space assets. Starting in 2009, the SSCP completed a study documenting potential customers and the business case for servicing, as well as defining several notional missions and required technologies. In 2010, SSCP moved to the implementation stage by completing several ground demonstrations and commencing development of two International Space Station (ISS) payloads-the Robotic Refueling Mission (RRM) and the Dextre Pointing Package (DPP)--to mitigate new technology risks for a robotic mission to service existing assets in geosynchronous orbit. This paper introduces the DPP, scheduled to fly in July of 2012 on the third operational SpaceX Dragon mission, and its Autonomous Rendezvous and Docking (AR&D) instruments. The combination of sensors and advanced avionics provide valuable on-orbit demonstrations of essential technologies for servicing existing vehicles, both cooperative and non-cooperative.

Virtual reality applications to automated rendezvous and capture

Science.gov (United States)

Hale, Joseph; Oneil, Daniel

Virtual Reality (VR) is a rapidly developing Human/Computer Interface (HCI) technology. The evolution of high-speed graphics processors and development of specialized anthropomorphic user interface devices, that more fully involve the human senses, have enabled VR technology. Recently, the maturity of this technology has reached a level where it can be used as a tool in a variety of applications. This paper provides an overview of: VR technology, VR activities at Marshall Space Flight Center (MSFC), applications of VR to Automated Rendezvous and Capture (AR&C), and identifies areas of VR technology that requires further development.

Medial collateral ligament tear entrapped within a proximal tibial physeal separation: imaging findings and operative reduction

Energy Technology Data Exchange (ETDEWEB)

McAnally, James L.; Eberhardt, Steven C.; Mlady, Gary W. [University of New Mexico, Department of Radiology, Albuquerque, NM (United States); Fitzpatrick, Jennifer; Bosch, Patrick [University of New Mexico, Department of Orthopaedics and Rehabilitation, Albuquerque, NM (United States)

2008-10-15

Entrapped soft tissues such as periosteum and tendons have been described within joints and physeal fractures in the literature and frequently result in irreducible fractures and posttraumatic growth disturbances. We believe this case represents a novel presentation of acute, preoperative, magnetic resonance (MR) imaging diagnosis of a torn medial collateral ligament entrapped within a proximal tibial physeal separation. This case is presented with MR imaging and operative correlation of the findings. (orig.)

Medial collateral ligament tear entrapped within a proximal tibial physeal separation: imaging findings and operative reduction

International Nuclear Information System (INIS)

McAnally, James L.; Eberhardt, Steven C.; Mlady, Gary W.; Fitzpatrick, Jennifer; Bosch, Patrick

2008-01-01

Entrapped soft tissues such as periosteum and tendons have been described within joints and physeal fractures in the literature and frequently result in irreducible fractures and posttraumatic growth disturbances. We believe this case represents a novel presentation of acute, preoperative, magnetic resonance (MR) imaging diagnosis of a torn medial collateral ligament entrapped within a proximal tibial physeal separation. This case is presented with MR imaging and operative correlation of the findings. (orig.)

Endoscopic dilation of complete oesophageal obstructions with a combined antegrade-retrograde rendezvous technique.

Science.gov (United States)

Bertolini, Reto; Meyenberger, Christa; Putora, Paul Martin; Albrecht, Franziska; Broglie, Martina Anja; Stoeckli, Sandro J; Sulz, Michael Christian

2016-02-21

To investigate the combined antegrade-retrograde endoscopic rendezvous technique for complete oesophageal obstruction and the swallowing outcome. This single-centre case series includes consecutive patients who were unable to swallow due to complete oesophageal obstruction and underwent combined antegrade-retrograde endoscopic dilation (CARD) within the last 10 years. The patients' demographic characteristics, clinical parameters, endoscopic therapy, adverse events, and outcomes were obtained retrospectively. Technical success was defined as effective restoration of oesophageal patency. Swallowing success was defined as either percutaneous endoscopic gastrostomy (PEG)-tube independency and/or relevant improvement of oral food intake, as assessed by the functional oral intake scale (FOIS) (≥ level 3). The cohort consisted of six patients [five males; mean age 71 years (range, 54-74)]. All but one patient had undergone radiotherapy for head and neck or oesophageal cancer. Technical success was achieved in five out of six patients. After discharge, repeated dilations were performed in all five patients. During follow-up (median 27 mo, range, 2-115), three patients remained PEG-tube dependent. Three of four patients achieved relevant improvement of swallowing (two patients: FOIS 6, one patient: FOIS 7). One patient developed mediastinal emphysema following CARD, without a need for surgery. The CARD technique is safe and a viable alternative to high-risk blind antegrade dilation in patients with complete proximal oesophageal obstruction. Although only half of the patients remained PEG-tube independent, the majority improved their ability to swallow.

Failed common bile duct cannulation during pregnancy: Rescue with endoscopic ultrasound guided rendezvous procedure.

Science.gov (United States)

Singla, Vikas; Arora, Anil; Tyagi, Pankaj; Sharma, Praveen; Bansal, Naresh; Kumar, Ashish

2016-01-01

Common bile duct (CBD) stones can lead to serious complications and require intervention with either endoscopic retrograde cholangiopancreatography (ERCP) or laparoscopic techniques for urgent relief. On an average 10%-20% of the patients with gall bladder stones can have associated CBD stones. CBD stones during pregnancy can be associated with hazardous complications for both the mother and the fetus. Failed cannulation while performing ERCP during pregnancy is a technically demanding situation, which requires immediate rescue with special techniques. Conventional rescue techniques may not be feasible and can be associated with hazardous consequences. Endoscopic ultrasound (EUS) guided rendezvous technique has now emerged as a safe alternative, and in one of our patients, this technique was successfully attempted. To the best of our knowledge, this is the first case report in the literature on EUS-guided rendezvous procedure during pregnancy.

The association between proximity to animal feeding operations and community health: a systematic review.

Directory of Open Access Journals (Sweden)

Annette M O'Connor

2010-03-01

Full Text Available A systematic review was conducted for the association between animal feeding operations (AFOs and the health of individuals living near AFOs.The review was restricted to studies reporting respiratory, gastrointestinal and mental health outcomes in individuals living near AFOs in North America, European Union, United Kingdom, and Scandinavia. From June to September 2008 searches were conducted in PUBMED, CAB, Web-of-Science, and Agricola with no restrictions. Hand searching of narrative reviews was also used. Two reviewers independently evaluated the role of chance, confounding, information, selection and analytic bias on the study outcome. Nine relevant studies were identified. The studies were heterogeneous with respect to outcomes and exposures assessed. Few studies reported an association between surrogate clinical outcomes and AFO proximity. A negative association was reported when odor was the measure of exposure to AFOs and self-reported disease, the measure of outcome. There was evidence of an association between self-reported disease and proximity to AFO in individuals annoyed by AFO odor.There was inconsistent evidence of a weak association between self-reported disease in people with allergies or familial history of allergies. No consistent dose response relationship between exposure and disease was observable.

A Proposed Strategy for the U.S. to Develop and Maintain a Mainstream Capability Suite ("Warehouse") for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond

Science.gov (United States)

Krishnakumar, Kalmanje S.; Stillwater, Ryan A.; Babula, Maria; Moreau, Michael C.; Riedel, J. Ed; Mrozinski, Richard B.; Bradley, Arthur; Bryan, Thomas C.

2012-01-01

The ability of space assets to rendezvous and dock/capture/berth is a fundamental enabler for numerous classes of NASA fs missions, and is therefore an essential capability for the future of NASA. Mission classes include: ISS crew rotation, crewed exploration beyond low-Earth-orbit (LEO), on-orbit assembly, ISS cargo supply, crewed satellite servicing, robotic satellite servicing / debris mitigation, robotic sample return, and robotic small body (e.g. near-Earth object, NEO) proximity operations. For a variety of reasons to be described, NASA programs requiring Automated/Autonomous Rendezvous and Docking/Capture/Berthing (AR&D) capabilities are currently spending an order-of-magnitude more than necessary and taking twice as long as necessary to achieve their AR&D capability, "reinventing the wheel" for each program, and have fallen behind all of our foreign counterparts in AR&D technology (especially autonomy) in the process. To ensure future missions' reliability and crew safety (when applicable), to achieve the noted cost and schedule savings by eliminate costs of continually "reinventing the wheel ", the NASA AR&D Community of Practice (CoP) recommends NASA develop an AR&D Warehouse, detailed herein, which does not exist today. The term "warehouse" is used herein to refer to a toolbox or capability suite that has pre-integrated selectable supply-chain hardware and reusable software components that are considered ready-to-fly, low-risk, reliable, versatile, scalable, cost-effective, architecture and destination independent, that can be confidently utilized operationally on human spaceflight and robotic vehicles over a variety of mission classes and design reference missions, especially beyond LEO. The CoP also believes that it is imperative that NASA coordinate and integrate all current and proposed technology development activities into a cohesive cross-Agency strategy to produce and utilize this AR&D warehouse. An initial estimate indicates that if NASA

An integrated autonomous rendezvous and docking system architecture using Centaur modern avionics

Science.gov (United States)

Nelson, Kurt

1991-01-01

The avionics system for the Centaur upper stage is in the process of being modernized with the current state-of-the-art in strapdown inertial guidance equipment. This equipment includes an integrated flight control processor with a ring laser gyro based inertial guidance system. This inertial navigation unit (INU) uses two MIL-STD-1750A processors and communicates over the MIL-STD-1553B data bus. Commands are translated into load activation through a Remote Control Unit (RCU) which incorporates the use of solid state relays. Also, a programmable data acquisition system replaces separate multiplexer and signal conditioning units. This modern avionics suite is currently being enhanced through independent research and development programs to provide autonomous rendezvous and docking capability using advanced cruise missile image processing technology and integrated GPS navigational aids. A system concept was developed to combine these technologies in order to achieve a fully autonomous rendezvous, docking, and autoland capability. The current system architecture and the evolution of this architecture using advanced modular avionics concepts being pursued for the National Launch System are discussed.

Mission operations for unmanned nuclear electric propulsion outer planet exploration with a thermionic reactor spacecraft.

Science.gov (United States)

Spera, R. J.; Prickett, W. Z.; Garate, J. A.; Firth, W. L.

1971-01-01

Mission operations are presented for comet rendezvous and outer planet exploration NEP spacecraft employing in-core thermionic reactors for electric power generation. The selected reference missions are the Comet Halley rendezvous and a Jupiter orbiter at 5.9 planet radii, the orbit of the moon Io. The characteristics of the baseline multi-mission NEP spacecraft are presented and its performance in other outer planet missions, such as Saturn and Uranus orbiters and a Neptune flyby, are discussed. Candidate mission operations are defined from spacecraft assembly to mission completion. Pre-launch operations are identified. Shuttle launch and subsequent injection to earth escape by the Centaur D-1T are discussed, as well as power plant startup and the heliocentric mission phases. The sequence and type of operations are basically identical for all missions investigated.

Lyapunov design of event-based controllers for the rendez-vous of coupled systems

NARCIS (Netherlands)

De Persis, Claudio; Postoyan, Romain

2014-01-01

The objective is to present a new type of triggering conditions together with new proof concepts for the event-based coordination of multi-agents. As a first step, we focus on the rendez-vous of two identical systems modeled as double integrators with additional damping in the velocity dynamics. The

Imaging Flash Lidar for Safe Landing on Solar System Bodies and Spacecraft Rendezvous and Docking

Science.gov (United States)

Amzajerdian, Farzin; Roback, Vincent E.; Bulyshev, Alexander E.; Brewster, Paul F.; Carrion, William A; Pierrottet, Diego F.; Hines, Glenn D.; Petway, Larry B.; Barnes, Bruce W.; Noe, Anna M.

2015-01-01

NASA has been pursuing flash lidar technology for autonomous, safe landing on solar system bodies and for automated rendezvous and docking. During the final stages of the landing from about 1 kilometer to 500 meters above the ground, the flash lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes. The onboard flight computer can then use the 3-D map of terrain to guide the vehicle to a safe location. As an automated rendezvous and docking sensor, the flash lidar can provide relative range, velocity, and bearing from an approaching spacecraft to another spacecraft or a space station. NASA Langley Research Center has developed and demonstrated a flash lidar sensor system capable of generating 16,000 pixels range images with 7 centimeters precision, at 20 Hertz frame rate, from a maximum slant range of 1800 m from the target area. This paper describes the lidar instrument and presents the results of recent flight tests onboard a rocket-propelled free-flyer vehicle (Morpheus) built by NASA Johnson Space Center. The flights were conducted at a simulated lunar terrain site, consisting of realistic hazard features and designated landing areas, built at NASA Kennedy Space Center specifically for this demonstration test. This paper also provides an overview of the plan for continued advancement of the flash lidar technology aimed at enhancing its performance to meet both landing and automated rendezvous and docking applications.

Rendezvous cannulation technique reduces post-ERCP pancreatitis: a prospective nationwide study of 12,718 ERCP procedures.

Science.gov (United States)

Swahn, Fredrik; Nilsson, Magnus; Arnelo, Urban; Löhr, Matthias; Persson, Gunnar; Enochsson, Lars

2013-04-01

The aim of this study was to investigate if intraoperative rendezvous cannulation reduces the risk of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) because there is no universal consensus on the optimal treatment of common bile duct stones. We performed a nationwide case-control study, nested within the cohort of ERCP procedures reported to the Swedish Registry for Gallstone Surgery and ERCP (GallRiks), between 2007 and 2009. Data were collected prospectively from a web-based registry of ERCP procedures that includes variables such as patient characteristics, indication, cannulation technique, diagnostic findings, therapeutic measures, and complications. The primary outcome was PEP. The registry included 12,718 ERCP procedures performed on patients without a history of previous ERCP. The risk of PEP when using the rendezvous technique compared with those who were cannulated by conventional means was reduced from 3.6 to 2.2% (odds ratio (OR) 0.5, 95% confidence interval 0.2-0.9, P=0.02). Although a significant reduction there are overall relatively few cases with PEP and the calculated numbers needed to treat to avoid one case of PEP is as high as 71. Other factors associated with increased risk of PEP were young age, prolonged procedure time, and elective ERCP. Rendezvous bile duct cannulation during ERCP reduces the risk of PEP from 3.6 to 2.2% compared with conventional biliary cannulation.

COMPASS Final Report: Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER)

Science.gov (United States)

Oleson, Steven R.; McGuire, Melissa L.

2009-01-01

In this study, the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team completed a design for a multi-asteroid (Nereus and 1996 FG3) sample return capable spacecraft for the NASA In-Space Propulsion Office. The objective of the study was to support technology development and assess the relative benefits of different electric propulsion systems on asteroid sample return design. The design uses a single, heritage Orion solar array (SA) (approx.6.5 kW at 1 AU) to power a single NASA Evolutionary Xenon Thruster ((NEXT) a spare NEXT is carried) to propel a lander to two near Earth asteroids. After landing and gathering science samples, the Solar Electric Propulsion (SEP) vehicle spirals back to Earth where it drops off the first sample s return capsule and performs an Earth flyby to assist the craft in rendezvousing with a second asteroid, which is then sampled. The second sample is returned in a similar fashion. The vehicle, dubbed Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER), easily fits in an Atlas 401 launcher and its cost estimates put the mission in the New Frontier s (NF's) class mission.

Deep Interior: Multiple-Rendezvous Prospecting of NEOs

Science.gov (United States)

Kakuda, R. Y.; Asphaug, E.; Belton, M. J. S.; Gulkis, S.; Huebner, W. F.

2000-10-01

This is an international multiple-rendezvous mission designed to prospect the deep interior and subsurface geophysical properties of diverse near-Earth objects, using reflection radar tomography, imaging, gravity, and explosions. What we learn will greatly influence future missions and guide strategies for the diversion, disruption, or utilization of potentially hazardous objects. Deep Interior. Low-frequency radar to determine internal variations of complex permittivity at resolutions approaching 20 m. Map inclusions or voids, fracture geometries, and compositional or structural boundaries. Subsurface. High-frequency radar to determine depth of regolith, existence and nature of cometary mantle, geology beneath and around craters, and subsurface expressions to surface geology. Topography and Geodesy. Stereogrammetric imaging with 1 m/pixel spatial resolution, supplemented by radar altimetry in shadowed regions, to determine detailed shape, volume, and spin state. Compare with radar sounding to learn how internal structure is manifested on the surface. Mass and Density. Total mass and lower moments of the internal mass distribution by mapping the exterior gravitational field. Look for mass concentrations. Surface microphysics and composition. Map color, albedo, and scattering properties of the surface over sunlit regions in six optical filters. Material properties. Deploy grenades to characterize the mechanics and dynamics of surface materials. Record 8 frame/sec, 20 cm/pixel videos of crater formation and ejecta dynamics, to enable simple and direct laboratory constraints on material density, cohesion and porosity. Dust. Look for dust lofted by surface waves propagating from the explosions, to constrain elastic properties and attenuation. Observe longer-term dynamics and optical properties of dust "atmosphere" generated by human activity. Cometary Activity. At comet 107P/Wilson-Harrington, look for expressions of past cometary activity, and for possible awakening

Industrial Computed Tomography using Proximal Algorithm

KAUST Repository

Zang, Guangming

2016-04-14

In this thesis, we present ProxiSART, a flexible proximal framework for robust 3D cone beam tomographic reconstruction based on the Simultaneous Algebraic Reconstruction Technique (SART). We derive the proximal operator for the SART algorithm and use it for minimizing the data term in a proximal algorithm. We show the flexibility of the framework by plugging in different powerful regularizers, and show its robustness in achieving better reconstruction results in the presence of noise and using fewer projections. We compare our framework to state-of-the-art methods and existing popular software tomography reconstruction packages, on both synthetic and real datasets, and show superior reconstruction quality, especially from noisy data and a small number of projections.

Cow allergen (Bos d2) and endotoxin concentrations are higher in the settled dust of homes proximate to industrial-scale dairy operations.

Science.gov (United States)

Williams, D' Ann L; McCormack, Meredith C; Matsui, Elizabeth C; Diette, Gregory B; McKenzie, Shawn E; Geyh, Alison S; Breysse, Patrick N

2016-01-01

Airborne contaminants produced by industrial agricultural facilities contain chemical and biological compounds that can impact the health of residents living in close proximity. Settled dust can be a reservoir for these contaminants and can influence long-term exposures. In this study, we sampled the indoor- and outdoor-settled dust from 40 homes that varied in proximity to industrial-scale dairies (ISD; industrial-scale dairy, a term used in this paper to describe a large dairy farm and adjacent waste sprayfields, concentrated animal feeding operation or animal feeding operation, that uses industrial processes) in the Yakima Valley, Washington. We analyzed settled dust samples for cow allergen (Bos d2, a cow allergen associated with dander, hair, sweat and urine, it is a member of the lipocalin family of allergens associated with mammals), mouse allergen (Mus m1; major mouse allergen, a mouse urinary allergen, in the lipocalin family), dust mite allergens (Der p1 (Dermatophagoides pteronissinus 1) and Der f1 (Dermatophagoides farinae 1)), and endotoxin (a component of the cell walls of gram negative bacteria, lipopolysaccharide, which can be found in air and dust and can produce a strong inflammatory response). A concentration gradient was observed for Bos d2 and endotoxin measured in outdoor-settled dust samples based on proximity to ISD. Indoor-settled dust concentrations of Bos d2 and endotoxin were also highest in proximal homes. While the associated health effects of exposure to cow allergen in settled dust is unknown, endotoxin at concentrations observed in these proximal homes (100 EU/mg) has been associated with increased negative respiratory health effects. These findings document that biological contaminants emitted from ISDs are elevated in indoor- and outdoor-settled dust samples at homes close to these facilities and extend to as much as three miles (4.8 km) away.

Antimicrobial residues in animal waste and water resources proximal to large-scale swine and poultry feeding operations

Science.gov (United States)

Campagnolo, E.R.; Johnson, K.R.; Karpati, A.; Rubin, C.S.; Kolpin, D.W.; Meyer, M.T.; Esteban, J. Emilio; Currier, R.W.; Smith, K.; Thu, K.M.; McGeehin, M.

2002-01-01

Expansion and intensification of large-scale animal feeding operations (AFOs) in the United States has resulted in concern about environmental contamination and its potential public health impacts. The objective of this investigation was to obtain background data on a broad profile of antimicrobial residues in animal wastes and surface water and groundwater proximal to large-scale swine and poultry operations. The samples were measured for antimicrobial compounds using both radioimmunoassay and liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) techniques. Multiple classes of antimicrobial compounds (commonly at concentrations of >100 μg/l) were detected in swine waste storage lagoons. In addition, multiple classes of antimicrobial compounds were detected in surface and groundwater samples collected proximal to the swine and poultry farms. This information indicates that animal waste used as fertilizer for crops may serve as a source of antimicrobial residues for the environment. Further research is required to determine if the levels of antimicrobials detected in this study are of consequence to human and/or environmental ecosystems. A comparison of the radioimmunoassay and LC/ESI-MS analytical methods documented that radioimmunoassay techniques were only appropriate for measuring residues in animal waste samples likely to contain high levels of antimicrobials. More sensitive LC/ESI-MS techniques are required in environmental samples, where low levels of antimicrobial residues are more likely.

Antimicrobial residues in animal waste and water resources proximal to large-scale swine and poultry feeding operations.

Science.gov (United States)

Campagnolo, Enzo R; Johnson, Kammy R; Karpati, Adam; Rubin, Carol S; Kolpin, Dana W; Meyer, Michael T; Esteban, J Emilio; Currier, Russell W; Smith, Kathleen; Thu, Kendall M; McGeehin, Michael

2002-11-01

Expansion and intensification of large-scale animal feeding operations (AFOs) in the United States has resulted in concern about environmental contamination and its potential public health impacts. The objective of this investigation was to obtain background data on a broad profile of antimicrobial residues in animal wastes and surface water and groundwater proximal to large-scale swine and poultry operations. The samples were measured for antimicrobial compounds using both radioimmunoassay and liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) techniques. Multiple classes of antimicrobial compounds (commonly at concentrations of > 100 microg/l) were detected in swine waste storage lagoons. In addition, multiple classes of antimicrobial compounds were detected in surface and groundwater samples collected proximal to the swine and poultry farms. This information indicates that animal waste used as fertilizer for crops may serve as a source of antimicrobial residues for the environment. Further research is required to determine if the levels of antimicrobials detected in this study are of consequence to human and/or environmental ecosystems. A comparison of the radioimmunoassay and LC/ESI-MS analytical methods documented that radioimmunoassay techniques were only appropriate for measuring residues in animal waste samples likely to contain high levels of antimicrobials. More sensitive LC/ESI-MS techniques are required in environmental samples, where low levels of antimicrobial residues are more likely.

ProxImaL: efficient image optimization using proximal algorithms

KAUST Repository

Heide, Felix

2016-07-11

Computational photography systems are becoming increasingly diverse, while computational resources-for example on mobile platforms-are rapidly increasing. As diverse as these camera systems may be, slightly different variants of the underlying image processing tasks, such as demosaicking, deconvolution, denoising, inpainting, image fusion, and alignment, are shared between all of these systems. Formal optimization methods have recently been demonstrated to achieve state-of-the-art quality for many of these applications. Unfortunately, different combinations of natural image priors and optimization algorithms may be optimal for different problems, and implementing and testing each combination is currently a time-consuming and error-prone process. ProxImaL is a domain-specific language and compiler for image optimization problems that makes it easy to experiment with different problem formulations and algorithm choices. The language uses proximal operators as the fundamental building blocks of a variety of linear and nonlinear image formation models and cost functions, advanced image priors, and noise models. The compiler intelligently chooses the best way to translate a problem formulation and choice of optimization algorithm into an efficient solver implementation. In applications to the image processing pipeline, deconvolution in the presence of Poisson-distributed shot noise, and burst denoising, we show that a few lines of ProxImaL code can generate highly efficient solvers that achieve state-of-the-art results. We also show applications to the nonlinear and nonconvex problem of phase retrieval.

Rendezvous Protocols and Dynamic Frequency Hopping Interference Design for Anti-Jamming Satellite Communication

Science.gov (United States)

2013-11-25

previously considered this proactive approach to combat unintentional, persistent (non- reactive) interference . In this project, we plan on extending our...channel” (or code ) by chance, through public knowledge of the underlying protocol semantics , or by compromising one of the network devices. An alternative...AFRL-RV-PS- AFRL-RV-PS- TR-2013-0142 TR-2013-0142 RENDEZVOUS PROTOCOLS AND DYNAMIC FREQUENCY HOPPING INTERFERENCE DESIGN FOR ANTI-JAMMING

Modified Koyanagi Technique in Management of Proximal ...

African Journals Online (AJOL)

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Modified Koyanagi Technique in Management of Proximal Hypospadias. Adham Elsaied, Basem Saied, and Mohammed El- ... All operations were performed by the authors,using fine instruments and under 3.5X loupe ... the other needed an operation to close the fistula six months later. The case with meatal recession had ...

Proximal biceps rupture: management of an unusual injury in an arm wrestler

OpenAIRE

Pratt, D A; Tennent, T D

2007-01-01

Arm wrestling may cause unusual injuries, which may require operative repair in the sporting individual. Injury to the proximal biceps as a consequence of arm wrestling has not been reported previously. The diagnosis and treatment of a 36‐year‐old man who sustained a proximal biceps rupture while arm wrestling and his operative management are described.

Guidance and navigation for rendezvous with an uncooperative target

Science.gov (United States)

Telaar, J.; Schlaile, C.; Sommer, J.

2018-06-01

This paper presents a guidance strategy for a rendezvous with an uncooperative target. In the applied design reference mission, a spiral approach is commanded ensuring a collision-free relative orbit due to e/i-vector separation. The dimensions of the relative orbit are successively reduced by Δv commands which at the same time improve the observability of the relative state. The navigation is based on line-of-sight measurements. The relative state is estimated by an extended Kalman filter (EKF). The performance of this guidance and navigation strategy is demonstrated by extensive Monte Carlo simulations taking into account all major uncertainties like measurement errors, Δv execution errors, and differential drag.

Two-Step Proximal Gradient Algorithm for Low-Rank Matrix Completion

Directory of Open Access Journals (Sweden)

Qiuyu Wang

2016-06-01

Full Text Available In this paper, we  propose a two-step proximal gradient algorithm to solve nuclear norm regularized least squares for the purpose of recovering low-rank data matrix from sampling of its entries. Each iteration generated by the proposed algorithm is a combination of the latest three points, namely, the previous point, the current iterate, and its proximal gradient point. This algorithm preserves the computational simplicity of classical proximal gradient algorithm where a singular value decomposition in proximal operator is involved. Global convergence is followed directly in the literature. Numerical results are reported to show the efficiency of the algorithm.

The epidemiology and functional outcomes of operative fixation of extracapsular proximal femoral fractures (AO 31-A) in young adults.

Science.gov (United States)

Ramoutar, D N; Kodumuri, P; Rodrigues, J N; Olewicz, S; Moran, C G; Ollivere, B J; Forward, D P

2017-02-01

Proximal femoral fractures in adults under 50 years are not as common as in the elderly, but may have just as significant an impact. There is little in the literature describing the functional outcomes of fixation in this age group. Our aim was to assess the clinical and functional outcomes of operative management of extracapsular proximal femoral fractures (AO 31-A) in the young adult (age was 39 years (range 17-50) with a male preponderance (73.8%). Mean hospital stay was 14 days (range 2-94). Seventeen (19.3%) patients had died at a mean of 40 months from their operation date. The 1-year mortality was 4.5%. There were five complications (5.7%). SF-36 and EuroQol 5D scores showed that 5-10% had severe problems with a 20% decrease in quality of life compared to population norms. The biggest differences were in the physical function modalities. One-third had fair to poor hip function as assessed by the Oxford Hip Score. Though these injuries are relatively rare in this age group, they do have significant mortality and functional impairment reflecting a higher energy of injury rather than the frailty seen in the elderly.

Coherent Doppler lidar for automated space vehicle rendezvous, stationkeeping and capture

Science.gov (United States)

Bilbro, James A.

1991-01-01

The inherent spatial resolution of laser radar makes ladar or lidar an attractive candidate for Automated Rendezvous and Capture application. Previous applications were based on incoherent lidar techniques, requiring retro-reflectors on the target vehicle. Technology improvements (reduced size, no cryogenic cooling requirement) have greatly enhanced the construction of coherent lidar systems. Coherent lidar permits the acquisition of non-cooperative targets at ranges that are limited by the detection capability rather than by the signal-to-noise ratio (SNR) requirements. The sensor can provide translational state information (range, velocity, and angle) by direct measurement and, when used with any array detector, also can provide attitude information by Doppler imaging techniques. Identification of the target is accomplished by scanning with a high pulse repetition frequency (dependent on the SNR). The system performance is independent of range and should not be constrained by sun angle. An initial effort to characterize a multi-element detection system has resulted in a system that is expected to work to a minimum range of 1 meter. The system size, weight and power requirements are dependent on the operating range; 10 km range requires a diameter of 3 centimeters with overall size at 3 x 3 x 15 to 30 cm, while 100 km range requires a 30 cm diameter.

The endoscopic ultrasonography-guided rendezvous technique for biliary cannulation: a technical review.

Science.gov (United States)

Isayama, Hiroyuki; Nakai, Yousuke; Kawakubo, Kazumichi; Kawakami, Hiroshi; Itoi, Takao; Yamamoto, Natsuyo; Kogure, Hirofumi; Koike, Kazuhiko

2013-04-01

Steady progress is being made in endoscopic biliary intervention, especially endoscopic ultrasonography (EUS)-guided procedures. The EUS-guided rendezvous technique (EUS-RV) is a salvage method for failed selective biliary cannulation. The overall success rate of EUS-RV in 247 cases from seven published articles was 74 % and the incidence of complications was 11 %. The main cause of failed rendezvous cannulation was difficulty passing a biliary stricture or papilla due to poor guidewire (GW) manipulation. A recent large study found a 98.3 % success rate and superiority to precutting. This report suggested using a hydrophilic guidewire. Major complications were bleeding (0.8 %), bile leakage (1.2 %), peritonitis (0.4 %), pneumoperitoneum (0.2 %), and pancreatitis (1.6 %). The approach routes for EUS-RV were transgastric, transduodenal short position, and transduodenal long position. The appropriate route for each patient should be used. GW selection for EUS-RV is critical, and a hydrophilic GW might be the most useful. The catheter can be inserted through the papilla alongside or over the wire. Alongside cannulation is convenient, but difficult. The problem with the over-the-wire technique is withdrawal of the GW in the accessory channel. EUS-RV is effective and safe, but is not established. The efficacy should be confirmed in a prospective comparative trial, and the necessary specialist equipment should be developed.

Use of a Proximity Sensor Switch for "Hands Free" Operation of Computer-Based Video Prompting by Young Adults with Moderate Intellectual Disability

Science.gov (United States)

Ivey, Alexandria N.; Mechling, Linda C.; Spencer, Galen P.

2015-01-01

In this study, the effectiveness of a "hands free" approach for operating video prompts to complete multi-step tasks was measured. Students advanced the video prompts by using a motion (hand wave) over a proximity sensor switch. Three young adult females with a diagnosis of moderate intellectual disability participated in the study.…

Design and development of a Space Station proximity operations research and development mockup

Science.gov (United States)

Haines, Richard F.

1986-01-01

Proximity operations (Prox-Ops) on-orbit refers to all activities taking place within one km of the Space Station. Designing a Prox-Ops control station calls for a comprehensive systems approach which takes into account structural constraints, orbital dynamics including approach/departure flight paths, myriad human factors and other topics. This paper describes a reconfigurable full-scale mock-up of a Prox-Ops station constructed at Ames incorporating an array of windows (with dynamic star field, target vehicle(s), and head-up symbology), head-down perspective display of manned and unmanned vehicles, voice- actuated 'electronic checklist', computer-generated voice system, expert system (to help diagnose subsystem malfunctions), and other displays and controls. The facility is used for demonstrations of selected Prox-Ops approach scenarios, human factors research (work-load assessment, determining external vision envelope requirements, head-down and head-up symbology design, voice synthesis and recognition research, etc.) and development of engineering design guidelines for future module interiors.

The influence of spatial ability and experience on performance during spaceship rendezvous and docking.

Science.gov (United States)

Du, Xiaoping; Zhang, Yijing; Tian, Yu; Huang, Weifen; Wu, Bin; Zhang, Jingyu

2015-01-01

Manual rendezvous and docking (manual RVD) is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices, and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed.

The influence of spatial ability and experience on performance during spaceship rendezvous and docking

Science.gov (United States)

Du, Xiaoping; Zhang, Yijing; Tian, Yu; Huang, Weifen; Wu, Bin; Zhang, Jingyu

2015-01-01

Manual rendezvous and docking (manual RVD) is a challenging space task for astronauts. Previous research showed a correlation between spatial ability and manual RVD skills among participants at early stages of training, but paid less attention to experts. Therefore, this study tried to explore the role of spatial ability in manual RVD skills in two groups of trainees, one relatively inexperienced and the other experienced operators. Additionally, mental rotation has been proven essential in RVD and was tested in this study among 27 male participants, 15 novices, and 12 experts. The participants performed manual RVD tasks in a high fidelity simulator. Results showed that experience moderated the relation between mental rotation ability and manual RVD performance. On one hand, novices with high mental rotation ability tended to perform that RVD task more successfully; on the other hand, experts with high mental rotation ability showed not only no performance advantage in the final stage of the RVD task, but had certain disadvantages in their earlier processes. Both theoretical and practical implications were discussed. PMID:26236252

Endoscopic ultrasonography-guided pancreatic duct access: techniques and literature review of pancreatography, transmural drainage and rendezvous techniques.

Science.gov (United States)

Itoi, Takao; Kasuya, Kazuhiko; Sofuni, Atsushi; Itokawa, Fumihide; Kurihara, Toshio; Yasuda, Ichiro; Nakai, Yousuke; Isayama, Hiroyuki; Moriyasu, Fuminori

2013-05-01

Endoscopic ultrasonography-guided (EUS)-guided pancreatic interventions have gained increasing attention. Here we review EUS-guided pancreatic duct (PD) access techniques and outcomes. EUS-guided PD intervention is divided into two types, antegrade and rendezvous techniques, following EUS-guided pancreatography. In the antegrade technique, pancreaticoenterostomy is carried out by stent placement between the PD and the stomach, duodenum, or jejunum. Transenteric antegrade PD stenting is conducted by stent placement, advancing anteriorly into the PD through the pancreatic tract. The rendezvous technique is carried out by using a guidewire through the papilla or anastomotic site for retrograde stent insertion. In terms of EUS-guided PD stenting, 11 case reports totaling 75 patients (35 normal anatomy, 40 altered anatomy) have been published. The technical success rate was greater than 70%. Early adverse events, including severe hematoma and severe pancreatitis,occurred in seven (63.6%) of 11 reports. Regarding the rendezvous technique, 12 case reports totaling 52 patients (22 normal anatomy, 30 altered anatomy) have been published. The technical success rate ranged from 25% to 100%. It was 48% in one report that involved more than 20 cases. Once stents were placed, all patients became free of symptoms. Early mild adverse events occurred in four (36.4%) of 11 reports. In conclusion, although it can be risky because of possible serious or even fatal adverse events, including pancreatic juice leakage, perforation and severe acute pancreatitis, EUS-PD access seems to be promising for treating symptomatic pancreatic diseases caused by PD stricture and pancreaticoenterostomy stricture. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

Proximal caries detection: Sirona Sidexis versus Kodak Ektaspeed Plus.

Science.gov (United States)

Khan, Emad A; Tyndall, Donald A; Ludlow, John B; Caplan, Daniel

2005-01-01

This study compared the accuracy of intraoral film and a charge-coupled device (CCD) receptor for proximal caries detection. Four observers evaluated images of the proximal surfaces of 40 extracted posterior teeth. The presence or absence of caries was scored using a five-point confidence scale. The actual status of each surface was determined from ground section histology. Responses were evaluated by means of receiver operating characteristic (ROC) analysis. Areas under ROC curves (Az) were assessed through a paired t-test. The performance of the CCD-based intraoral sensor was not different statistically from Ektaspeed Plus film in detecting proximal caries.

[Operative treatment of proximal humeral four-part fractures in elderly patients: comparison of two angular-stable implant systems].

Science.gov (United States)

Kuhlmann, T; Hofmann, T; Seibert, O; Gundlach, G; Schmidt-Horlohé, K; Hoffmann, R

2012-04-01

Although being one of the most common fractures in elderly patients, there is still no standardised treatment protocol for four-part fractures of the proximal humerus. However, a wide variety of angular-stable implants is available. The present retrospective study compares the clinical and radiological outcome following operative treatment of four-part fractures of the proximal humerus with the Philos system (Philos, proximal humeral internal locking system, Synthes GmbH, Umkirch Germany) and the angular-stable Königsee plate system (Königsee Implantate GmbH, Allendorf, Germany) in patients older than 65 years. From July 2005 until December 2007 we identified 77 patients with a four-part fracture of the proximal humerus who were treated operatively with one of the two implant systems. Of the patients, 17 could not be located so that in total 60 patients (78 %) participated in this study. The mean age of the 30 patients (10 m, 20 f) in the Philos group was 69 years (65-92), whereas the mean age of the 30 patients (11 m, 19 f) in the Königsee group was 71 years (65-93). A comprehensive assessment was performed after a median of 17 months (12-24), including physical examination, radiographic examination and completion of the disabilities of the arm, shoulder and hand score (DASH) and the Constant score (CS) as patient-oriented, limb-specific questionnaires. Neither in the Philos nor in the Königsee group could excellent results be achieved. Using the CS 13 patients (43 %) of the Philos group achieved a good and 15 (50 %) a satisfactory result. Bad results were found in 2 patients (7 %). The mean CS was 61.53 points. In the Königsee group mean CS was 61.76 points. In detail, 14 patients (47 %) treated with the Königsee implant were rated as good and 15 (50 %) as satisfactory. Only 1 patient (3 %) was rated as poor. No significant statistical differences were found between the groups. Mean DASH score in the Philos group was 56.30 points and 55.37 points in the K�

Visual Control for Multirobot Organized Rendezvous.

Science.gov (United States)

Lopez-Nicolas, G; Aranda, M; Mezouar, Y; Sagues, C

2012-08-01

This paper addresses the problem of visual control of a set of mobile robots. In our framework, the perception system consists of an uncalibrated flying camera performing an unknown general motion. The robots are assumed to undergo planar motion considering nonholonomic constraints. The goal of the control task is to drive the multirobot system to a desired rendezvous configuration relying solely on visual information given by the flying camera. The desired multirobot configuration is defined with an image of the set of robots in that configuration without any additional information. We propose a homography-based framework relying on the homography induced by the multirobot system that gives a desired homography to be used to define the reference target, and a new image-based control law that drives the robots to the desired configuration by imposing a rigidity constraint. This paper extends our previous work, and the main contributions are that the motion constraints on the flying camera are removed, the control law is improved by reducing the number of required steps, the stability of the new control law is proved, and real experiments are provided to validate the proposal.

Laparoendoscopic rendezvous in the treatment of cholecysto-choledocholitiasis: a single series of 200 patients.

Science.gov (United States)

La Barba, Giuliano; Gardini, Andrea; Cavargini, Elena; Casadei, Alessandro; Morgagni, Paolo; Bazzocchi, Francesca; D'Acapito, Fabrizio; Cavaliere, Davide; Curti, Roberta; Tringali, Domenico; Cucchetti, Alessandro; Ercolani, Giorgio

2018-02-27

Although the ideal management of cholecysto-choledocholitiasis is controversial, the two-stage approach, namely the common bile duct (CBD) clearance through endoscopic retrograde cholangiopancreatography (ERCP) followed by laparoscopic cholecystectomy, remains the standard way of management. However, whenever feasible, the one-stage approach, using the so-called "laparoendoscopic rendezvous" (LERV) technique, offers some advantages, mainly reducing the hospital stay and the risk of post-ERCP pancreatitis. The aim of this study was to evaluate the safety and the efficacy of the one-stage approach, and to compare our results with data from available large studies. We reviewed our series of consecutive patients with cholecysto-choledocholitiasis treated by LERV from January 2003, to October 2016. Both elective and emergency cases were included. The primary end-point was the efficacy to obtain the CBD stones clearance. Secondary end-points were morbidity and mortality, operative time, conversion rate, and in-hospital stay. A total of 200 patients underwent a LERV procedure for the intra-operative diagnosis by intra-operative cholangiogram of cholecysto-choledocholitiasis. In 187 patients (93.5%), it was possible to cannulate the cystic duct with the jag-wire. Success rate was 95%. Conversion rate was 3%. The mean operative time was 135 min and the mean in-hospital stay was 4 days. 29 (14.5%) were the early complications, six mild pancreatitis. Four patients required re-operation during the hospital stay. 11 patients (5.5%) developed late complications during a median follow-up of 57.7 months. Our results confirm that LERV technique is a safe procedure with high success rates for the treatment of cholecysto-choledocholitiasis. The major advantages include the single-stage treatment, the shorter hospital stay, and the lower incidence of post-ERCP pancreatitis.

Radiation effects in the Si-PIN detector on the Near Earth Asteroid Rendezvous mission

CERN Document Server

Starr, R; Evans, L G; Floyd, S R; McClanahan, T P; Trombka, J I; Goldsten, J O; Maurer, R H; McNutt, R L; Roth, D R

1999-01-01

A Si-PIN photodiode is being used as a solar X-ray monitor on the X-ray/gamma-ray spectrometer experiment which is flying on the Near Earth Asteroid Rendezvous spacecraft. Since its launch in February 1996 this photodiode has experienced several brief failures. These anomalies and other performance characteristics will be described. Efforts to reproduce these failures in ground tests with flight spare equipment will also be discussed.

NEP for a Kuiper Belt Object rendezvous mission

International Nuclear Information System (INIS)

Lipinski, Ronald J.; Lenard, Roger X.; Wright, Steven A.; Houts, Michael G.; Patton, Bruce; Poston, David I.

2000-01-01

Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOs with a diameter greater than 100 km. KBOs are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOs. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total DV of 46 km/s. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=0). Alternatively, the system could be placed into a 700-km earth orbit with more propellant, yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All

NEP for a Kuiper Belt Object Rendezvous Mission

International Nuclear Information System (INIS)

HOUTS, MICHAEL G.; LENARD, ROGER X.; LIPINSKI, RONALD J.; PATTON, BRUCE; POSTON, DAVID I.; WRIGHT, STEVEN A.

1999-01-01

Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOS with a diameter greater than 100 km. KBOS are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOS. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total ΔV of 46 krnk. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=O). Alternatively, the system could be placed into a 700-km earth orbit with more propellant,yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All

[Pathologic proximal femoral fractures in children in an unicameral bone cyst].

Science.gov (United States)

Havránek, P; Pesl, T; Bartonícek, J

2005-01-01

Proximal femoral fractures in children are rare, pathologic fractures being extremely rare. Despite many meanings these fractures are still "unsolved" there are some definite rules for treatment of true accidental injuries. Pathologic fractures are outstanding with their extremely rare incidence. The aim of the study is to overview a large clinical material, find out the incidence of this pathologic fracture, the extent and shape of the unicameral bone cyst (UBC), specific therapeutic approach, technical problems of eventual osteosynthesis, number of reoperations and sequels. Altogether 49 children with 50 accidental and pathologic fractures of proximal part of the femur treated in the Regional Pediatric Trauma Centre of the Department of Pediatric and Trauma Surgery, 3rd Faculty of Medicine, Charles University, Prague. Retrospective and prospective study of children (0 to 15 years of age) treated with proximal femoral accidental and pathologic fractures during the 20 year period (from August 1984 to November 2004). Classification of fractures according to Delbet and Colonna. Diagnosis of bone cyst with plain X-rays, eventually CT scans. During the 20 years period (August 1984 to November 2004) 49 children with 50 proximal femoral fractures were treated in the Department. Four patients sustained a pathologic fracture through an unicameral bone cyst. Two of these latter children were treated by an open reduction and osteosynthesis with the use of the proximal femoral AO-ASIF angled-plate and two children nonoperatively using skeletal traction because of impossibility of insertion of the osteosynthetic material without a damage of the growth plate. Subsequent operations of the UBC were necessary in these two children. All four patients recovered well without sequels. Pathologic fractures in UBC are usually treated nonoperatively and the cyst itself is treated after fracture healing. Proximal femoral impairment is the exception from this rule because of weigh bearing

Endoscopic ultrasound rendezvous for bile duct access using a transduodenal approach: cumulative experience at a single center. A case series.

Science.gov (United States)

Kim, Y S; Gupta, K; Mallery, S; Li, R; Kinney, T; Freeman, M L

2010-06-01

Endoscopic ultrasound (EUS)-assisted biliary access is utilized when conventional endoscopic retrograde cholangiopancreatography (ERCP) fails. We report a 10-year experience utilizing a transduodenal EUS rendezvous via a transpapillary route without dilation of the transduodenal tract, followed by immediate ERCP access. Patients included all EUS-guided rendezvous procedures for biliary access that were performed following ERCP failure. EUS-assisted bile duct puncture was performed via a transduodenal approach and a guide wire was advanced through the papilla without any dilation or bougienage of the tract; ERCP was performed immediately afterwards. EUS-assisted biliary rendezvous was attempted in 15 patients (mean age 66 +/- 18.2 years; malignant = 10, benign = 5). Mean diameter of measured bile ducts was 14.3 +/- 5.17 mm (range 4-23 mm). The reasons for initial ERCP failure were tumor infiltration or edema (n = 9), intradiverticular papilla (n = 2), pre-existing duodenal stent (n = 1), and anatomic anomalies (n = 3). Successful EUS-guided bile duct puncture and wire passage were achieved in all 15 patients (100 %), with drainage being successful in 12 / 15 (80 %). Failures occurred in three patients due to inability to traverse the biliary stricture (n = 2) or dissection of a choledochocele with the guide wire (n = 1); all were subsequently drained via percutaneous methods. Stents placed were metallic in eight patients and plastic in four. Complications consisted of moderate pancreatitis after a difficult ERCP attempt in one patient, and bacteremia after percutaneous biliary drainage in another. There were no instances of perforation, extraluminal air or fluid collections. EUS-assisted biliary drainage utilizing a transduodenal rendezvous approach demonstated a high success rate without any complications directly attributable to the EUS access. Advantages over percutaneous biliary and other methods of EUS biliary access include performance under the same

Image-guided ureteral reconstruction using rendezvous technique for complex ureteric transection after gunshot injuries.

Science.gov (United States)

Arabi, Mohammad; Mat'hami, Abdulaziz; Said, Mohammad T; Bulbul, Muhammad; Haddad, Maurice; Al-Kutoubi, Aghiad

2016-01-01

Management of complex ureteric transection poses a significant clinical challenge, particularly after gunshot injuries due to marked distortion of anatomy and associated tissue loss. We report two cases of total ureteric transection due to gunshot injury successfully repaired using fluoroscopy-guided rendezvous procedure and double J stent placement. This minimally invasive approach may offer a safe and effective technique to repair complete ureteral transection and obviate the need for complex surgical procedures.

Dynamical analysis of rendezvous and docking with very large space infrastructures in non-Keplerian orbits

Science.gov (United States)

Colagrossi, Andrea; Lavagna, Michèle

2018-03-01

A space station in the vicinity of the Moon can be exploited as a gateway for future human and robotic exploration of the solar system. The natural location for a space system of this kind is about one of the Earth-Moon libration points. The study addresses the dynamics during rendezvous and docking operations with a very large space infrastructure in an EML2 Halo orbit. The model takes into account the coupling effects between the orbital and the attitude motion in a circular restricted three-body problem environment. The flexibility of the system is included, and the interaction between the modes of the structure and those related with the orbital motion is investigated. A lumped parameter technique is used to represents the flexible dynamics. The parameters of the space station are maintained as generic as possible, in a way to delineate a global scenario of the mission. However, the developed model can be tuned and updated according to the information that will be available in the future, when the whole system will be defined with a higher level of precision.

Endo-laparoscopic rendezvous approach for pericardia with gastric posterior wall of gastrointestinal stromal tumor: Analysis of 52 consecutive cases

Directory of Open Access Journals (Sweden)

Po Ding

2014-01-01

Conclusions: Endo-laparoscopic rendezvous approach is considered to represent the next revolution in surgery. The new technique is reliable and effective in clinical application, due to the advantages of accurate and quick localization for pericardial GIST within gastric posterior wall.

Endomedullar nail of metacarpal and proximal phalanges

International Nuclear Information System (INIS)

Mendez Olaya, Francisco Javier; Sanchez Mesa, Pedro Antonio

2002-01-01

Prospective study, series of cases; it included patients with diaphysis fractures and union diaphysis-neck or union diaphysis-base of metacarpal and proximal phalanges, in whom was practiced anterograde intramedullary nailing previous closed reduction of the fracture, using prevent intramedullary nail of 1.6 mm. (cem 16) for the metacarpal fractures, and two nail prevent of 1.0 mm. (cem 10) for the proximal phalangeal fractures. Indications: transverse and oblique short fractures, spiral and with comminuting bicortical. Pursuit average is 5.7 months. Frequency surgical intervened patient: 2.2 each month, using this surgical technique a total of 20 (twenty) patients have been operated, 21 (twenty one) fractures; 16 (sixteen) metacarcal fractures and 5 (five) proximal phalangeal fractures, all of them tested using clinical and radiological parameters. Results: good 82%, regular 18%, and bad 0% obtaining bony consolidation and early rehabilitation with incorporation to their habitual works

Video-Guidance Design for the DART Rendezvous Mission

Science.gov (United States)

Ruth, Michael; Tracy, Chisholm

2004-01-01

NASA's Demonstration of Autonomous Rendezvous Technology (DART) mission will validate a number of different guidance technologies, including state-differenced GPS transfers and close-approach video guidance. The video guidance for DART will employ NASA/Marshall s Advanced Video Guidance Sensor (AVGS). This paper focuses on the terminal phase of the DART mission that includes close-approach maneuvers under AVGS guidance. The closed-loop video guidance design for DART is driven by a number of competing requirements, including a need for maximizing tracking bandwidths while coping with measurement noise and the need to minimize RCS firings. A range of different strategies for attitude control and docking guidance have been considered for the DART mission, and design decisions are driven by a goal of minimizing both the design complexity and the effects of video guidance lags. The DART design employs an indirect docking approach, in which the guidance position targets are defined using relative attitude information. Flight simulation results have proven the effectiveness of the video guidance design.

Robust control for constant thrust rendezvous under thrust failure

Directory of Open Access Journals (Sweden)

Qi Yongqiang

2015-04-01

Full Text Available A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapunov function subject to linear matrix inequalities. Secondly, the robust controllers satisfying the requirements can be designed by solving this optimization problem. Then, a new algorithm of constant thrust fitting is proposed through the impulse compensation and the fuel consumption under the theoretical continuous thrust and the actual constant thrust is calculated and compared by using the method proposed in this paper. Finally, the proposed method having the advantage of saving fuel is proved and the actual constant thrust switch control laws are obtained through the isochronous interpolation method, meanwhile, an illustrative example is provided to show the effectiveness of the proposed control design method.

IUS/TUG orbital operations and mission support study. Volume 4: Project planning data

Science.gov (United States)

1975-01-01

Planning data are presented for the development phases of interim upper stage (IUS) and tug systems. Major project planning requirements, major event schedules, milestones, system development and operations process networks, and relevant support research and technology requirements are included. Topics discussed include: IUS flight software; tug flight software; IUS/tug ground control center facilities, personnel, data systems, software, and equipment; IUS mission events; tug mission events; tug/spacecraft rendezvous and docking; tug/orbiter operations interface, and IUS/orbiter operations interface.

The rendezvous technique involving insertion of a guidewire in a percutaneous transhepatic gallbladder drainage tube for biliary access in a case of difficult biliary cannulation.

Science.gov (United States)

Sunada, Fumiko; Morimoto, Naoki; Tsukui, Mamiko; Kurata, Hidekazu

2017-05-01

Endoscopic retrograde cholangiopancreatography (ERCP) is a diagnostic method and treatment approach for biliary diseases. However, biliary cannulation can be difficult in some cases. We performed ERCP in a 97-year-old woman with abdominal pain resulting from acute cholangitis caused by choledocholithiasis and observed difficult biliary cannulation. Eventually, the patient was successfully treated with the rendezvous technique. We could not cannulate the biliary duct during ERCP twice. Therefore, we placed a percutaneous transhepatic gallbladder drainage (PTGBD) tube without intrahepatic dilation. The rendezvous technique was performed using the PTGBD tube. The patient did not experience pancreatitis or perforation.

Effect of angiotensin II receptor blockade on proximal tubular fluid reabsorption

DEFF Research Database (Denmark)

Leyssac, P P; Karlsen, F M; Holstein-Rathlou, N H

1997-01-01

flow rate decreased by 2.0 +/- 0.8 nl/min, and early distal NaCl concentration decreased by 4.3 +/- 0.8 mM (mean +/- SE). No changes were observed after microperfusion with saline. Because the tubuloglomerular feedback mechanism was operating in the closed-loop mode, the decreased NaCl load...... to the macula densa will be compensated by an increase in the single-nephron glomerular filtration rate. In agreement with this, the early proximal flow rate, measured proximal to the site of losartan administration, increased by 5.7 +/- 1.3 nl/min. The increase in the rate of proximal reabsorption between...

A Review of Tiangong-1/Shenzhou-8 Rendezvous and Docking Mission%天宫一号／神舟八号交会对接任务总体评述

Institute of Scientific and Technical Information of China (English)

周建平

2012-01-01

The complete success of Tiangong-1/Shenzhou-8 rendezvous and docking mission represents a great breakthrough of China in space rendezvous and docking technology. A basic introduction of Tiangong-land Shenzhou-8 rendezvous and docking mission is presented, with the general evaluation of the mission and its main achievements being put forward.%天宫一号／神舟八号交会对接任务圆满成功，标志着我国空间交会对接技术取得重大突破。本文介绍了天宫一号目标飞行器与神舟八号飞船交会对接飞行任务的基本情况、总体评价及主要成果。

OSIRIS-REx Orbit Determination Covariance Studies at Bennu

Science.gov (United States)

Antreasian, P. G.; Moreau, M.; Jackman, C.; Williams, K.; Page, B.; Leonard, J. M.

2016-01-01

The Origins Spectral Interpretation Resource Identification Security Regolith Explorer (OSIRIS-REx) mission is a NASA New Frontiers mission launching in 2016 to rendezvous with the small, Earth-crossing asteroid (101955) Bennu in late 2018, and ultimately return a sample of regolith to Earth. Approximately 3 months before the encounter with Bennu, the asteroid finally becomes detectable in the narrow field PolyCam imager. The spacecraft's rendezvous with Bennu begins with a series of four Asteroid Approach Maneuvers, which slow the spacecraft's speed relative to Bennu beginning two and a half months prior to closest approach, ultimately delivering the spacecraft to a point 18 km from Bennu on Nov 18, 2018. An extensive campaign of proximity operations activities to characterize the properties of Bennu and select a suitable sample site will follow. This paper will discuss the challenges of navigating near a small 500-m diameter asteroid. The navigation at close proximity is dependent on the accurate mathematical model or digital terrain map of the asteroids shape. Predictions of the spacecraft state are very sensitive to spacecraft small forces, solar radiation pressure, and mis-modeling of Bennu's gravity field. Uncertainties in the physical parameters of the central body Bennu create additional challenges. The navigation errors are discussed and their impact on science planning will be presented.

Proximal Humerus

NARCIS (Netherlands)

Diercks, Ron L.; Bain, Gregory; Itoi, Eiji; Di Giacomo, Giovanni; Sugaya, Hiroyuki

2015-01-01

This chapter describes the bony structures of the proximal humerus. The proximal humerus is often regarded as consisting of four parts, which assists in understanding function and, more specially, describes the essential parts in reconstruction after fracture or in joint replacement. These are the

76 FR 54163 - Proximity Detection Systems for Continuous Mining Machines in Underground Coal Mines

Science.gov (United States)

2011-08-31

... Detection Systems for Continuous Mining Machines in Underground Coal Mines AGENCY: Mine Safety and Health... (except full-face continuous mining machines) with proximity detection systems. Miners working near..., each underground coal mine operator would be required to install proximity detection systems on...

La formation continue des usagers : évaluation qualitative des rendez-vous d'évaluation post-permis pour les conducteurs novices. Thème 11. Rapport final

OpenAIRE

CHATENET, F; TORRES, S; GAUTHIER, P; PERVANCHON, M

2001-01-01

Rapport final de convention DSCR/INRETS. Le présent rapport fait état de l'évaluation qualitative des rendez-vous d'évaluation (RVE) pour les conducteurs novices, le volet des rendez-vous de perfectionnement (RVP) pour les conducteurs expérimentés sera abordé ultérieurement dans le cadre d'une convention DSCR/INRETS. La première partie développe les problématiques et les objectifs poursuivis par cette étude ainsi que la méthodologie qui a été utilisée. Les trois autres parties présentent les...

Attitude Determination and Control System Design for a 6U Cube Sat for Proximity Operations and Rendezvous

Science.gov (United States)

2014-08-04

entire rartge in steps of 1 % due to the rapid solenoid valve actuation. The requirement of the control system is to provide pointing control accuracy of...and accuracy are discussed. 1S. SUBJECT TERMS Nanosatellite, laser rangefinder, ARAP AIMA, USAF, object imaging, shape reconstruction, space-based...thrusters can be modulated over the entire range in steps of 1% due to the rapid solenoid valve actuation. The requirement of the control system is to

Sciatic Nerve Injury After Proximal Hamstring Avulsion and Repair.

Science.gov (United States)

Wilson, Thomas J; Spinner, Robert J; Mohan, Rohith; Gibbs, Christopher M; Krych, Aaron J

2017-07-01

Muscle bellies of the hamstring muscles are intimately associated with the sciatic nerve, putting the sciatic nerve at risk of injury associated with proximal hamstring avulsion. There are few data informing the magnitude of this risk, identifying risk factors for neurologic injury, or determining neurologic outcomes in patients with distal sciatic symptoms after surgery. To characterize the frequency and nature of sciatic nerve injury and distal sciatic nerve-related symptoms after proximal hamstring avulsion and to characterize the influence of surgery on these symptoms. Cohort study; Level of evidence, 3. This was a retrospective review of patients with proximal partial or complete hamstring avulsion. The outcome of interest was neurologic symptoms referable to the sciatic nerve distribution below the knee. Neurologic symptoms in operative patients were compared pre- and postoperatively. The cohort consisted of 162 patients: 67 (41.4%) operative and 95 (58.6%) nonoperative. Sciatic nerve-related symptoms were present in 22 operative and 23 nonoperative patients, for a total of 45 (27.8%) patients (8 [4.9%] motor deficits, 11 [6.8%] sensory deficits, and 36 [22.2%] with neuropathic pain). Among the operative cohort, 3 of 3 (100.0%) patients showed improvement in their motor deficit postoperatively, 3 of 4 (75.0%) patients' sensory symptoms improved, and 17 of 19 (89.5%) patients had improvement in pain. A new or worsening deficit occurred in 5 (7.5%) patients postoperatively (2 [3.1%] motor deficits, 1 [1.5%] sensory deficit, and 3 [4.5%] with new pain). Predictors of operative intervention included lower age (odds ratio [OR], 0.952; 95% CI, 0.921-0.982; P = .001) and complete avulsion (OR, 10.292; 95% CI, 2.526-72.232; P hamstring avulsion are underrecognized. Currently, neurologic symptoms are not considered when determining whether to pursue operative intervention. Given the high likelihood of improvement with surgical treatment, neurologic symptoms should be

Usefulness of the 'Rendezvous' Technique in Living Related Right Liver Donors with Postoperative Biliary Leakage from Bile Duct Anastomosis

International Nuclear Information System (INIS)

Miraglia, R.; Traina, M.; Maruzzelli, L.; Caruso, S.; Di Pisa, M.; Gruttadauria, S.; Luca, A.; Gridelli, B.

2008-01-01

This is a report on two cases of large bile leak following right hepatectomy performed for living related liver transplantation, originating from the stump of the ligated right bile duct, and treated with the placement of large percutaneous biliary catheters through a combined percutaneous transhepatic and endoscopic approach (rendezvous technique).

Transluminal recanalization of chronic total occlusion of radial artery using rendezvous technique: a case report and literature review.

Science.gov (United States)

Arabi, Mohammad; Ahmed, Ishtiaq; Qattan, Nabeel

2014-01-01

Although endovascular management of lower extremity peripheral arterial disease (PAD) is well studied, little information exists regarding endovascular treatment of critical upper limb ischemia. We report a case of transluminal recanalization of right radial artery chronic total occlusion (CTO) using rendezvous technique in a patient with critical hand ischemia and dry gangrene of the right index finger.

System and Method for Automated Rendezvous, Docking and Capture of Autonomous Underwater Vehicles

Science.gov (United States)

Stone, William C. (Inventor); Clark, Evan (Inventor); Richmond, Kristof (Inventor); Paulus, Jeremy (Inventor); Kapit, Jason (Inventor); Scully, Mark (Inventor); Kimball, Peter (Inventor)

2018-01-01

A system for automated rendezvous, docking, and capture of autonomous underwater vehicles at the conclusion of a mission comprising of comprised of a docking rod having lighted, pulsating (in both frequency and light intensity) series of LED light strips thereon, with the LEDs at a known spacing, and the autonomous underwater vehicle specially designed to detect and capture the docking rod and then be lifted structurally by a spherical end strop about which the vehicle can be pivoted and hoisted up (e.g., onto a ship). The method of recovery allows for very routine and reliable automated recovery of an unmanned underwater asset.

Efficacy of the Laparoendoscopic "Rendezvous" to Treat Cholecystocholedocholithiasis in 210 Consecutive Patients: A Single Center Experience.

Science.gov (United States)

La Greca, Gaetano; Pesce, Antonio; Vitale, Marco; Mannino, Maurizio; Di Marco, Federica; Di Blasi, Michele; Lombardo, Rosario; Puleo, Stefano; Russello, Domenico; Latteri, Saverio

2017-08-01

The simultaneous laparoendoscopic "rendezvous" (LERV) represents an alternative to sequential or totally laparoscopic approaches for patients affected by cholecystocholedocholithiasis. The aim of this study was to analyze the results in a large series of 210 consecutive patients. From 2002 to 2016 all patients affected by cholecystocholedocholithiasis were treated with a standardized "tailored" LERV. The relevant technical features of the procedure were recorded. An analysis of feasibility, effectiveness in stone clearance, and safety was performed. Among 214 patients with common bile duct stones, 210 were treated with LERV and 4 with open rendezvous approach. Intraoperative cholangiography confirmed common bile duct stones in 179 patients (85.2%) or sludge in 18 (8.5%) and in 98.9% stone clearance was obtained endoscopically. Endoscopic papilla cannulation was feasible in 161 patients (76.7%), whereas in 49 (23.3%) a transcystic guidewire was needed. The overall LERV feasibility was 96.6%. The conversion rate to open surgery was 3.3%. Minor morbidity was observed in 1.9% of cases, mortality in 0.47%, and the mean hospital stay was 4.3 days. These results confirm the high effectiveness of LERV. This approach to treat cholecystocholedocholithiasis should be preferred and therefore implemented where a strong collaboration between surgeons and endoscopists is possible.

Treatment of Unstable Trochanteric Femur Fractures: Proximal Femur Nail Versus Proximal Femur Locking Compression Plate.

Science.gov (United States)

Singh, Ashutosh Kumar; Narsaria, Nidi; G R, Arun; Srivastava, Vivek

Unstable trochanteric femur fractures are common fractures that are difficult to manage. We conducted a prospective study to compare functional outcomes and complications of 2 different implant designs, proximal femur nail (PFN) and proximal femur locking compression plate (PFLCP), used in internal fixation of unstable trochanteric femur fractures. On hospital admission, 48 patients with unstable trochanteric fractures were randomly assigned (using a sealed envelope method) to treatment with either PFN (24 patients) or PFLCP (24 patients). Perioperative data and complications were recorded. All cases were followed up for 2 years. The groups did not differ significantly (P > .05) in operative time, reduction quality, complications, hospital length of stay, union rate, or time to union. Compared with the PFLCP group, the PFN group had shorter incisions and less blood loss. Regarding functional outcomes, there was no significant difference in mean Harris Hip Score (P = .48) or Palmer and Parker mobility score (P = .58). Both PFN and PFLCP are effective in internal fixation of unstable trochanteric femur fractures.

GASPACHO: a generic automatic solver using proximal algorithms for convex huge optimization problems

Science.gov (United States)

Goossens, Bart; Luong, Hiêp; Philips, Wilfried

2017-08-01

Many inverse problems (e.g., demosaicking, deblurring, denoising, image fusion, HDR synthesis) share various similarities: degradation operators are often modeled by a specific data fitting function while image prior knowledge (e.g., sparsity) is incorporated by additional regularization terms. In this paper, we investigate automatic algorithmic techniques for evaluating proximal operators. These algorithmic techniques also enable efficient calculation of adjoints from linear operators in a general matrix-free setting. In particular, we study the simultaneous-direction method of multipliers (SDMM) and the parallel proximal algorithm (PPXA) solvers and show that the automatically derived implementations are well suited for both single-GPU and multi-GPU processing. We demonstrate this approach for an Electron Microscopy (EM) deconvolution problem.

Transluminal Recanalization of Chronic Total Occlusion of Radial Artery Using Rendezvous Technique: A Case Report and Literature Review

Directory of Open Access Journals (Sweden)

Mohammad Arabi

2014-01-01

Full Text Available Although endovascular management of lower extremity peripheral arterial disease (PAD is well studied, little information exists regarding endovascular treatment of critical upper limb ischemia. We report a case of transluminal recanalization of right radial artery chronic total occlusion (CTO using rendezvous technique in a patient with critical hand ischemia and dry gangrene of the right index finger.

Electromagnetic Signal Feedback Control for Proximity Detection Systems

Science.gov (United States)

Smith, Adam K.

Coal is the most abundant fossil fuel in the United States and remains an essential source of energy. While more than half of coal production comes from surface mining, nearly twice as many workers are employed by underground operations. One of the key pieces of equipment used in underground coal mining is the continuous mining machine. These large and powerful machines are operated in confined spaces by remote control. Since 1984, 40 mine workers in the U. S. have been killed when struck or pinned by a continuous mining machine. It is estimated that a majority of these accidents could have been prevented with the application of proximity detection systems. While proximity detection systems can significantly increase safety around a continuous mining machine, there are some system limitations. Commercially available proximity warning systems for continuous mining machines use magnetic field generators to detect workers and establish safe work areas around the machines. Several environmental factors, however, can influence and distort the magnetic fields. To minimize these effects, a control system has been developed using electromagnetic field strength and generator current to stabilize and control field drift induced by internal and external environmental factors. A laboratory test set-up was built using a ferrite-core magnetic field generator to produce a stable magnetic field. Previous work based on a field-invariant magnetic flux density model, which generically describes the electromagnetic field, is expanded upon. The analytically established transferable shell-based flux density distribution model is used to experimentally validate the control system. By controlling the current input to the ferrite-core generator, a more reliable and consistent magnetic field is produced. Implementation of this technology will improve accuracy and performance of existing commercial proximity detection systems. These research results will help reduce the risk of traumatic

Design of intelligent proximity detection zones to prevent striking and pinning fatalities around continuous mining machines.

Science.gov (United States)

Bissert, P T; Carr, J L; DuCarme, J P; Smith, A K

2016-01-01

The continuous mining machine is a key piece of equipment used in underground coal mining operations. Over the past several decades these machines have been involved in a number of mine worker fatalities. Proximity detection systems have been developed to avert hazards associated with operating continuous mining machines. Incorporating intelligent design into proximity detection systems allows workers greater freedom to position themselves to see visual cues or avoid other hazards such as haulage equipment or unsupported roof or ribs. However, intelligent systems must be as safe as conventional proximity detection systems. An evaluation of the 39 fatal accidents for which the Mine Safety and Health Administration has published fatality investigation reports was conducted to determine whether the accident may have been prevented by conventional or intelligent proximity. Multiple zone configurations for the intelligent systems were studied to determine how system performance might be affected by the zone configuration. Researchers found that 32 of the 39 fatalities, or 82 percent, may have been prevented by both conventional and intelligent proximity systems. These results indicate that, by properly configuring the zones of an intelligent proximity detection system, equivalent protection to a conventional system is possible.

Correction of Misclassifications Using a Proximity-Based Estimation Method

Directory of Open Access Journals (Sweden)

Shmulevich Ilya

2004-01-01

Full Text Available An estimation method for correcting misclassifications in signal and image processing is presented. The method is based on the use of context-based (temporal or spatial information in a sliding-window fashion. The classes can be purely nominal, that is, an ordering of the classes is not required. The method employs nonlinear operations based on class proximities defined by a proximity matrix. Two case studies are presented. In the first, the proposed method is applied to one-dimensional signals for processing data that are obtained by a musical key-finding algorithm. In the second, the estimation method is applied to two-dimensional signals for correction of misclassifications in images. In the first case study, the proximity matrix employed by the estimation method follows directly from music perception studies, whereas in the second case study, the optimal proximity matrix is obtained with genetic algorithms as the learning rule in a training-based optimization framework. Simulation results are presented in both case studies and the degree of improvement in classification accuracy that is obtained by the proposed method is assessed statistically using Kappa analysis.

Combined Radial and Femoral Access Strategy and Radial-Femoral Rendezvous in Patients With Long and Complex Iliac Occlusions.

Science.gov (United States)

Hanna, Elias B; Mogabgab, Owen N; Baydoun, Hassan

2018-01-01

We present cases of complex, calcified iliac occlusive disease revascularized via a combined radial-femoral access strategy. Through a 6-French, 125-cm transradial guiding catheter, antegrade guidewires and catheters are advanced into the iliac occlusion, while retrograde devices are advanced transfemorally. The transradial and transfemoral channels communicate, allowing the devices to cross the occlusion into the true lumen (radial-femoral antegrade-retrograde rendezvous).

Radiation tolerant design - theory and practice for proximity sensing

International Nuclear Information System (INIS)

Sharp, R.E.; Pater, S.L.; Cook, J.

1999-01-01

This paper provides a description of the radiation tolerant design process used to develop a range of proximity detectors with guaranteed total dose lifetime. It also describes some of the applications in which the detectors are being used and the benefits gained by plant operators. (authors)

Pollinators' mating rendezvous and the evolution of floral advertisement.

Science.gov (United States)

Fishman, Michael A; Hadany, Lilach

2013-01-07

Successful cross-fertilization in plant species that rely on animal pollinators depends not just on the number of pollinator visits, but also on these visits' duration. Furthermore, in non-deceptive pollination, a visit's duration depends on the magnitude of the reward provided to the pollinator. Accordingly, plants that rely on biotic pollination have to partition their investment in cross-fertilization assurance between attracting pollinator visits - advertisement, and rewarding visitors to assure that the visit is of productive duration. Here we analyze these processes by a combination of optimality methods and game theoretical modeling. Our results indicate that the optimality in such allocation of resources depends on the types of reward offered to the pollinators. More precisely, we show that plants that offer both food reward and mating rendezvous to pollinators will evolve to allocate a higher proportion of their cross-fertilization assurance budget to advertisement than plants that offer only food reward. That is, our results indicate that pollinators' mating habits may play a role in floral evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Proximal Alternating Direction Method with Relaxed Proximal Parameters for the Least Squares Covariance Adjustment Problem

Directory of Open Access Journals (Sweden)

Minghua Xu

2014-01-01

Full Text Available We consider the problem of seeking a symmetric positive semidefinite matrix in a closed convex set to approximate a given matrix. This problem may arise in several areas of numerical linear algebra or come from finance industry or statistics and thus has many applications. For solving this class of matrix optimization problems, many methods have been proposed in the literature. The proximal alternating direction method is one of those methods which can be easily applied to solve these matrix optimization problems. Generally, the proximal parameters of the proximal alternating direction method are greater than zero. In this paper, we conclude that the restriction on the proximal parameters can be relaxed for solving this kind of matrix optimization problems. Numerical experiments also show that the proximal alternating direction method with the relaxed proximal parameters is convergent and generally has a better performance than the classical proximal alternating direction method.

Adaptive relative pose control of spacecraft with model couplings and uncertainties

Science.gov (United States)

Sun, Liang; Zheng, Zewei

2018-02-01

The spacecraft pose tracking control problem for an uncertain pursuer approaching to a space target is researched in this paper. After modeling the nonlinearly coupled dynamics for relative translational and rotational motions between two spacecraft, position tracking and attitude synchronization controllers are developed independently by using a robust adaptive control approach. The unknown kinematic couplings, parametric uncertainties, and bounded external disturbances are handled with adaptive updating laws. It is proved via Lyapunov method that the pose tracking errors converge to zero asymptotically. Spacecraft close-range rendezvous and proximity operations are introduced as an example to validate the effectiveness of the proposed control approach.

Rendezvous technique treatment for late-onset biliary leakage after major hepatectomy of a living donor: report of a case.

Science.gov (United States)

Kimura, Koichi; Ikegami, Toru; Yamashita, Yo-ichi; Saeki, Hiroshi; Oki, Eiji; Yoshizumi, Tomoharu; Uchiyama, Hideaki; Kawanaka, Hirofumi; Soejima, Yuji; Morita, Masaru; Shirabe, Ken; Ikeda, Tetsuo; Maehara, Yoshihiko

2013-09-01

Biliary leakage is a major complication after hepatectomy. We report the case of a living-donor liver transplantation (LDLT) donor with a late-onset bile leak from the trifurcation of the hepatic duct who was successfully treated using rendezvous technique. A 52-year-old man underwent extended left hepatectomy for donation and was discharged on postoperative day (PD) 13. However, he was rehospitalized on PD 26 with severe abdominal pain. Physical examination suggested panperitonitis, and abdominocentesis showed bilious ascites. Emergent laparotomy for biliary leakage and peritonitis was performed. There was bilious ascites in the peritoneal cavity. A biliary fistula was recognized at the trifurcation of B8a, B8b, and B5. Intraoperative transhepatic biliary drainage of each bile duct was performed. Endoscopic transpapillary drainage was performed on PD 24. Finally, external drains were removed and complete internal drainage established on PD 70. The bile leak was considered to be the result of injury from electrocautery device. Appropriate making choices of the electrocautery devices enable us to avoid over thermal injury of the liver surface. Rendezvous bidirectional drainage effectively treated late-onset bile leakage from the trifurcation of a hepatic bile duct.

Humeral lengthening and proximal deformity correction with monorail external fixator in young adults.

Science.gov (United States)

Ruan, Hongjiang; Zhu, Yi; Liu, Shen; Kang, Qinglin

2018-05-01

Several humeral lengthening or simultaneous deformity corrections through one osteotomy using various external fixators were reported, while literature regarding correction of shortening and proximal varus deformity is scarce. This retrospective clinical study evaluated the results of preforming an acute correction and delayed lengthening in young adults through two osteotomies using monorail external fixator. We report seven patients with various pathologies who underwent humeral proximal deformity correction and lengthening between 2009 and 2015. Pre-operative and post-operative clinical and radiographic data were collected. The mean follow-up time was 33.4 months (25-46 months). The humeral neck-shaft angle improved from 97.9° (85-110°) to 138.6° (135-145°). The magnitude of lengthening achieved was average 7.6 cm (range, 6-10 cm) at an average healing index of lengthening of 30.2 days/cm (range, 27.7-35.4 days/cm). There was a significant increase in range of shoulder abduction, and active abduction improved from pre-operative 136.4° (range, 95-160°) to post-operative 166.4° (range, 150-180°). The DASH score improved significance from 23.29 ± 8.36 to 6.57 ± 3.65 (t = 4.848; p monorail external fixator can be used for humeral shortening and proximal varus angular deformity. Functional improvement is expected after surgery and post-operative therapy.

Robust control for spacecraft rendezvous system with actuator unsymmetrical saturation: a gain scheduling approach

Science.gov (United States)

Wang, Qian; Xue, Anke

2018-06-01

This paper has proposed a robust control for the spacecraft rendezvous system by considering the parameter uncertainties and actuator unsymmetrical saturation based on the discrete gain scheduling approach. By changing of variables, we transform the actuator unsymmetrical saturation control problem into a symmetrical one. The main advantage of the proposed method is improving the dynamic performance of the closed-loop system with a region of attraction as large as possible. By the Lyapunov approach and the scheduling technology, the existence conditions for the admissible controller are formulated in the form of linear matrix inequalities. The numerical simulation illustrates the effectiveness of the proposed method.

Proximity credentials: A survey

International Nuclear Information System (INIS)

Wright, L.J.

1987-04-01

Credentials as a means of identifying individuals have traditionally been a photo badge and more recently, the coded credential. Another type of badge, the proximity credential, is making inroads in the personnel identification field. This badge can be read from a distance instead of being veiewed by a guard or inserted into a reading device. This report reviews proximity credentials, identifies the companies marketing or developing proximity credentials, and describes their respective credentials. 3 tabs

Peri-operative antibiotic treatment of bacteriuria reduces early deep surgical site infections in geriatric patients with proximal femur fracture.

Science.gov (United States)

Langenhan, Ronny; Bushuven, Stefanie; Reimers, Niklas; Probst, Axel

2018-04-01

The aim of this study was to conduct a re-evaluation of current strategies for peri-operative prophylaxis of infections in orthopaedic surgery of geriatric patients (≥65 years) with proximal femoral fractures (PFF). Between 01/2010 and 08/2014 all post-operative infections after stabilization of PFF of 1,089 geriatric patients were recorded retrospectively. All patients pre-operatively received a single dose of 1.5 g cefuroxime (group 1). These were compared to prospectively determined post-operative rates of surgical site infection (SSI) of 441 geriatric patients, which were operated on between 09/2014 and 03/2017 due to PFF. In this second group we investigated the urinary tract on admission. Bacteriuria was treated with the pre-operative single dose of 1.5 g cefuroxime along with ciprofloxacin for five days, beginning on admission. Level of significance was set to p infection. Multi-resistant pathogens were found in 15 patients and pathogens were cefuroxime-resistant in 37. The differences of SSI after at least three months were 2.1% in group 1 and 0.45% in group 2 for all patients with surgery of PFF (p < 0.02) and for those with arthroplasty (p < 0.037) significant. The immediate antibiotic therapy of a prevalent bacteriuria for five days decreases the risk of SSI after surgery of PFF. Our single-centre study can only point out the problem of prevalent reservoirs of pathogens and the need for treatment. Evidence-based therapy concepts (indications of antibiotics, classes, duration) have to be developed in multi-centric and prospective studies.

Fascioperichondrial Flap with a Proximal Base Combined with Prominent Ear Surgery

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Heval Selman Özkan

2017-08-01

Full Text Available Objective: In this article, we present a personalized surgical technique to relocate a fascioperichondrial flap with a proximal base as an additional measure to improve results and hide sharp edges which frequently occur following traditional otoplasty. Materials and Methods: Fascioperichondrial flap with a proximal base prepared from the dorsal side was transposed to the anterior helix and conchal excision side and secured with stitches to hide visible edges and reinforce Furnas sutures. Nine patients operated for prominent ear deformity using this modification were included in the study and follow-up period was at least 6 months. Conchal mastoid distances were calculated from the superior and middle third of the ears before and after the operation, also in follow-up controls to determine the efficiency of the method. Results: There were no suture extrusions, skin necrosis or infection. The mean difference for both the upper and middle third of the ears were considerably lower (p≤0.05 at the end of six month after the operation. There were no visible skin edges and discomfort described by the patients. Conclusion: Fascioperichondrial flap with a proximal base repositioning to conchal side is an easy procedure that can be applied simply as an adjunct to traditional techniques. Addition of this flap provides an additional tissue to reinforce suture repair and, the results seem to be more durable and strong. Another main advantage of this flap is eliminating the unnatural visible breakpoints in the conchal bowl.

Combined radiologic and endoscopic treatment (using the “rendezvous technique”) of a biliary fistula following left hepatectomy

Science.gov (United States)

Gracient, Aurélien; Rebibo, Lionel; Delcenserie, Richard; Yzet, Thierry; Regimbeau, Jean-Marc

2016-01-01

Despite the ongoing decrease in the frequency of complications after hepatectomy, biliary fistulas still occur and are associated with high morbidity and mortality rates. Here, we report on an unusual technique for managing biliary fistula following left hepatectomy in a patient in whom the right posterior segmental duct joined the left hepatic duct. The biliary fistula was treated with a combined radiologic and endoscopic procedure based on the “rendezvous technique”. The clinical outcome was good, and reoperation was not required. PMID:27570431

Single Balloon Enteroscopy-Assisted ERCP Using Rendezvous Technique for Sharp Angulation of Roux-en-Y Limb in a Patient with Bile Duct Stones

Science.gov (United States)

Itoi, Takao; Ishii, Kentaro; Sofuni, Atsushi; Itokawa, Fumihide; Kurihara, Toshio; Tsuchiya, Takayoshi; Tsuji, Shujiro; Umeda, Junko; Moriyasu, Fuminori

2009-01-01

The acute angulation of Roux-en-Y (R-Y) limb precludes endoscopic access for endoscopic retrograde cholangiopancreatography (ERCP) even using a balloon enteroscopy. Here, we describe a case of successful single balloon enteroscopy (SBE)-assisted ERCP using a rendezvous technique in a patient with sharply angulated R-Y limb in a 79-year-old woman who had bile duct stones. Method. At first, a guidewire was passed antegradely through the major papilla after the needle puncture using percutaneous transhepatic biliary drainage technique. A hydrophilic guidewire with an ERCP catheter was antegradely advanced beyond the Roux limb. After a guidewire was firmly grasped by a snare forceps, it was pulled out of the body, resulting that the enteroscope could advance to the papilla. After papillary dilation, complete removal of bile duct stones was achieved without any procedure-related complication. In conclusion, although further study is needed, SBE-assisted ERCP using a rendezvous technique may have a potential for selected patients. PMID:20169091

Single Balloon Enteroscopy-Assisted ERCP Using Rendezvous Technique for Sharp Angulation of Roux-en-Y Limb in a Patient with Bile Duct Stones

Directory of Open Access Journals (Sweden)

Takao Itoi

2009-01-01

Full Text Available The acute angulation of Roux-en-Y (R-Y limb precludes endoscopic access for endoscopic retrograde cholangiopancreatography (ERCP even using a balloon enteroscopy. Here, we describe a case of successful single balloon enteroscopy (SBE-assisted ERCP using a rendezvous technique in a patient with sharply angulated R-Y limb in a 79-year-old woman who had bile duct stones. Method. At first, a guidewire was passed antegradely through the major papilla after the needle puncture using percutaneous transhepatic biliary drainage technique. A hydrophilic guidewire with an ERCP catheter was antegradely advanced beyond the Roux limb. After a guidewire was firmly grasped by a snare forceps, it was pulled out of the body, resulting that the enteroscope could advance to the papilla. After papillary dilation, complete removal of bile duct stones was achieved without any procedure-related complication. In conclusion, although further study is needed, SBE-assisted ERCP using a rendezvous technique may have a potential for selected patients.

Asteroid Rendezvous Mission Design Using Multiobjective Particle Swarm Optimization

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Ya-zhong Luo

2014-01-01

Full Text Available A new preliminary trajectory design method for asteroid rendezvous mission using multiobjective optimization techniques is proposed. This method can overcome the disadvantages of the widely employed Pork-Chop method. The multiobjective integrated launch window and multi-impulse transfer trajectory design model is formulated, which employes minimum-fuel cost and minimum-time transfer as two objective functions. The multiobjective particle swarm optimization (MOPSO is employed to locate the Pareto solution. The optimization results of two different asteroid mission designs show that the proposed approach can effectively and efficiently demonstrate the relations among the mission characteristic parameters such as launch time, transfer time, propellant cost, and number of maneuvers, which will provide very useful reference for practical asteroid mission design. Compared with the PCP method, the proposed approach is demonstrated to be able to provide much more easily used results, obtain better propellant-optimal solutions, and have much better efficiency. The MOPSO shows a very competitive performance with respect to the NSGA-II and the SPEA-II; besides a proposed boundary constraint optimization strategy is testified to be able to improve its performance.

A proximal point algorithm with generalized proximal distances to BEPs

OpenAIRE

Bento, G. C.; Neto, J. X. Cruz; Lopes, J. O.; Soares Jr, P. A.; Soubeyran, A.

2014-01-01

We consider a bilevel problem involving two monotone equilibrium bifunctions and we show that this problem can be solved by a proximal point method with generalized proximal distances. We propose a framework for the convergence analysis of the sequences generated by the algorithm. This class of problems is very interesting because it covers mathematical programs and optimization problems under equilibrium constraints. As an application, we consider the problem of the stability and change dyna...

Rendezvous with connectivity preservation for multi-robot systems with an unknown leader

Science.gov (United States)

Dong, Yi

2018-02-01

This paper studies the leader-following rendezvous problem with connectivity preservation for multi-agent systems composed of uncertain multi-robot systems subject to external disturbances and an unknown leader, both of which are generated by a so-called exosystem with parametric uncertainty. By combining internal model design, potential function technique and adaptive control, two distributed control strategies are proposed to maintain the connectivity of the communication network, to achieve the asymptotic tracking of all the followers to the output of the unknown leader system, as well as to reject unknown external disturbances. It is also worth to mention that the uncertain parameters in the multi-robot systems and exosystem are further allowed to belong to unknown and unbounded sets when applying the second fully distributed control law containing a dynamic gain inspired by high-gain adaptive control or self-tuning regulator.

Concepts of Operations for Asteroid Rendezvous Missions Focused on Resources Utilization

Science.gov (United States)

Mueller, Robert P.; Sibille, Laurent; Sanders, Gerald B.; Jones, Christopher A.

2014-01-01

Several asteroids are the targets of international robotic space missions currently manifested or in the planning stage. This global interest reflects a need to study these celestial bodies for the scientific information they provide about our solar system, and to better understand how to mitigate the collision threats some of them pose to Earth. Another important objective of these missions is providing assessments of the potential resources that asteroids could provide to future space architectures. In this paper, we examine a series of possible mission operations focused on advancing both our knowledge of the types of asteroids suited for different forms of resource extraction, and the capabilities required to extract those resources for mission enhancing and enabling uses such as radiation protection, propulsion, life support, shelter and manufacturing. An evolutionary development and demonstration approach is recommended within the framework of a larger campaign that prepares for the first landings of humans on Mars. As is the case for terrestrial mining, the development and demonstration approach progresses from resource prospecting (understanding the resource, and mapping the 'ore body'), mining/extraction feasibility and product assessment, pilot operations, to full in-situ resource utilization (ISRU). Opportunities to gather specific knowledge for ISRU via resource prospecting during science missions to asteroids are also examined to maximize the pace of development of needed ISRU capabilities and technologies for deep space missions.

Distributed fluorescent optical fiber proximity sensor: Towards a proof of concept

Science.gov (United States)

Gălătuș, Ramona; Faragó, Paul; Miluski, Piotr; Valles, Juan-Antonio

2018-06-01

Fluorescent fibers are optical fibers which emit light as a response to an incident phenomenon, usually an incident light. Operation depends on the doping dyes, which determine specific fluorescence and optical characteristics useful in the development of optical sensors. In this work we propose a low-cost distributed proximity sensor implemented using a red fluorescent fiber, to provide a security option for a surface plasmon resonance system. Operation of the proposed sensor relies on having the incident illumination intensity varied by the presence or absence of an obstacle in the vicinity of the sensing element. This will influence the radiated fluorescence accordingly. The proposed setup for the implementation of the optical proximity sensor assumes having a high brightness LED deployed for axial fiber illumination and a blue LED for side illumination. Electronic processing then accounts for gain and digitization. Measurement results of the prototype validate the proposed concept.

VML 3.0 Reactive Sequencing Objects and Matrix Math Operations for Attitude Profiling

Science.gov (United States)

Grasso, Christopher A.; Riedel, Joseph E.

2012-01-01

VML (Virtual Machine Language) has been used as the sequencing flight software on over a dozen JPL deep-space missions, most recently flying on GRAIL and JUNO. In conjunction with the NASA SBIR entitled "Reactive Rendezvous and Docking Sequencer", VML version 3.0 has been enhanced to include object-oriented element organization, built-in queuing operations, and sophisticated matrix / vector operations. These improvements allow VML scripts to easily perform much of the work that formerly would have required a great deal of expensive flight software development to realize. Autonomous turning and tracking makes considerable use of new VML features. Profiles generated by flight software are managed using object-oriented VML data constructs executed in discrete time by the VML flight software. VML vector and matrix operations provide the ability to calculate and supply quaternions to the attitude controller flight software which produces torque requests. Using VML-based attitude planning components eliminates flight software development effort, and reduces corresponding costs. In addition, the direct management of the quaternions allows turning and tracking to be tied in with sophisticated high-level VML state machines. These state machines provide autonomous management of spacecraft operations during critical tasks like a hypothetic Mars sample return rendezvous and docking. State machines created for autonomous science observations can also use this sort of attitude planning system, allowing heightened autonomy levels to reduce operations costs. VML state machines cannot be considered merely sequences - they are reactive logic constructs capable of autonomous decision making within a well-defined domain. The state machine approach enabled by VML 3.0 is progressing toward flight capability with a wide array of applicable mission activities.

Sheath rendezvous method: a novel distal protection technique during endovascular treatment of subclavian artery occlusions.

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Haraguchi, Takuya; Urasawa, Kazushi; Nakama, Tatsuya; Nakagawa, Yuya; Tan, Michinao; Koshida, Ryoji; Sato, Katsuhiko

2016-10-01

To describe an innovative distal protection technique, "sheath rendezvous method", during endovascular treatment for subclavian arterial occlusions. 4.5F and 6F guiding sheath were inserted from left brachial and common femoral artery, respectively. 0.014″ guidewire retrogradely passed through occlusion and into antegrade sheath to establish a pull-through system. 3.0 mm balloon was used to expand occlusion and anchor to deliver retrograde sheath into antegrade one. Both sheaths locked by balloon dilatation crossed occlusion until antegrade sheath passed over lesion. Balloon expandable stent was delivered within antegrade sheath. Sheath was removed, and stent was implanted. We obtained an excellent outcome without complications.

Cost analysis of laparoendoscopic rendezvous versus preoperative ERCP and laparoscopic cholecystectomy in the management of cholecystocholedocholithiasis.

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Garbarini, Aldo; Reggio, Dario; Arolfo, Simone; Bruno, Marco; Passera, Roberto; Catalano, Giorgia; Barletti, Claudio; Salizzoni, Mauro; Morino, Mario; Petruzzelli, Luca; Arezzo, Alberto

2017-08-01

Evidence from controlled trials and meta-analyses suggests that laparoendoscopic rendezvous (LERV) is preferable to sequential treatment in the management of common bile duct stones. With this retrospective analysis of a prospective database that included consecutive patients treated for cholecystocholedocholithiasis at our institution between January 2007 and July 2015, we compared LERV with sequential treatment. The primary endpoint was global cost, defined as the cost/patient/hospital stay, and the secondary end points were efficacy and morbidity. Fisher's exact test or Mann-Whitney test was used. Of a total of 249 consecutive patients, 143 underwent LERV (group A) and 106 a two-stage procedure (group B). Based on an average cost of €613 for 1 day of hospital stay in the General Surgery Department, the overall median cost of treatment was €6403 for group A and €8194 for group B (p < 0.001). Operative time was significantly shorter (p < 0.001), and length of hospital stay was significantly longer for group B (p < 0.001). No mortality in either group was observed. The postoperative complications rate was significantly higher in group B than in group A (24.5 vs. 10.5%; p = 0.003). No significant difference in the postoperative pancreatitis rate or the number of patients with increased serum amylase at 24 h was observed in either group. Our study suggests that LERV is preferable to sequential treatment not only in terms of less morbidity, but also of lower costs accrued by a shorter hospital stay. However, the longer operative time raises multiple organizational issues in the coordination of surgery and endoscopy services.

Interstellar rendezvous missions employing fission propulsion systems

International Nuclear Information System (INIS)

Lenard, Roger X.; Lipinski, Ronald J.

2000-01-01

There has been a conventionally held nostrum that fission system specific power and energy content is insufficient to provide the requisite high accelerations and velocities to enable interstellar rendezvous missions within a reasonable fraction of a human lifetime. As a consequence, all forms of alternative mechanisms that are not yet, and may never be technologically feasible, have been proposed, including laser light sails, fusion and antimatter propulsion systems. In previous efforts, [Lenard and Lipinski, 1999] the authors developed an architecture that employs fission power to propel two different concepts: one, an unmanned probe, the other a crewed vehicle to Alpha Centauri within mission times of 47 to 60 years. The first portion of this paper discusses employing a variant of the ''Forward Resupply Runway'' utilizing fission systems to enable both high accelerations and high final velocities necessary for this type of travel. The authors argue that such an architecture, while expensive, is considerably less expensive and technologically risky than other technologically advanced concepts, and, further, provides the ability to explore near-Earth stellar systems out to distances of 8 light years or so. This enables the ability to establish independent human societies which can later expand the domain of human exploration in roughly eight light-year increments even presuming that no further physics or technology breakthroughs or advances occur. In the second portion of the paper, a technology requirement assessment is performed. The authors argue that reasonable to extensive extensions to known technology could enable this revolutionary capability

Observer-Based Stabilization of Spacecraft Rendezvous with Variable Sampling and Sensor Nonlinearity

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Zhuoshi Li

2013-01-01

Full Text Available This paper addresses the observer-based control problem of spacecraft rendezvous with nonuniform sampling period. The relative dynamic model is based on the classical Clohessy-Wiltshire equation, and sensor nonlinearity and sampling are considered together in a unified framework. The purpose of this paper is to perform an observer-based controller synthesis by using sampled and saturated output measurements, such that the resulting closed-loop system is exponentially stable. A time-dependent Lyapunov functional is developed which depends on time and the upper bound of the sampling period and also does not grow along the input update times. The controller design problem is solved in terms of the linear matrix inequality method, and the obtained results are less conservative than using the traditional Lyapunov functionals. Finally, a numerical simulation example is built to show the validity of the developed sampled-data control strategy.

Can arthroscopic rotator cuff repair prevent proximal migration of the humeral head?

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Pablo Sanz-Ruiz

2015-12-01

Full Text Available Introduction: Shoulder arthroscopy has become increasingly used in recent years, especially in rotator cuff repair. The purpose of this study was to determine whether arthroscopic rotator cuff repair could prevent proximal migration of the humeral head. Material and Methods: We performed a retrospective study of 56 patients suffering from shoulder pain. They were divided into two groups, one comprising patients with impingement syndrome who underwent acromioplasty only and another comprising patients with rotator cuff tear who underwent acromioplasty combined with rotator cuff repair. The pre-operative Hirooka angle and the results of the simple shoulder test (SST were compared after 1 year. Results: We found no differences between the groups for the Hirooka angle or SST results. We did find a significant difference (P<0.05 between pre-operative and post-operative SST results. Conclusions: Rotator cuff repair using arthroscopy is a minimally invasive procedure that improves function and prevents proximal migration of the humeral head after 1 year of follow-up. [Arch Clin Exp Surg 2015; 4(4.000: 190-195

Clinical cavitation and radiographic lesion depth in proximal surfaces in an Indian population

DEFF Research Database (Denmark)

Sansare, Kaustubh; Raghav, Mamta; Sontakke, Subodeh

2014-01-01

the developing world. Materials and methods. Relationship between clinical cavitation and radiographic caries lesion depth in proximal surfaces in an Indian population was assessed. Proximal surfaces (n = 126) without restorations were examined on bitewing radiographs in patients with suspected caries and lesion......Abstract Objectives. To assess the relationship between clinical cavitation and radiographic caries lesion depth in proximal surfaces of permanent posterior teeth in an Indian population. This study also assessed the clinical feasibility of applying 'western guidelines' to this population from...... to the radiographic findings of lesion depth, 80-100% of the lesions observed in outer dentine would lead to a false (non-operative) treatment decision. Conclusions. Radiographic shallow carious lesions were often cavitated in this population. The threshold for cavitation in this study population is suggested...

Proximal Opening Wedge Osteotomy Provides Satisfactory Midterm Results With a Low Complication Rate.

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Oravakangas, Rami; Leppilahti, Juhana; Laine, Vesa; Niinimäki, Tuukka

2016-01-01

Hallux valgus is one of the most common foot deformities. Proximal opening wedge osteotomy is used for the treatment of moderate and severe hallux valgus with metatarsus primus varus. However, hypermobility of the first tarsometatarsal joint can compromise the results of the operation, and a paucity of midterm results are available regarding proximal open wedge osteotomy surgery. The aim of the present study was to assess the midterm results of proximal open wedge osteotomy in a consecutive series of patients with severe hallux valgus. Thirty-one consecutive adult patients (35 feet) with severe hallux valgus underwent proximal open wedge osteotomy. Twenty patients (35.5%) and 23 feet (34.3%) were available for the final follow-up examination. The mean follow-up duration was 5.8 (range 4.6 to 7.0) years. The radiologic measurements and American Orthopaedic Foot and Ankle Society hallux-metatarsophalangeal-interphalangeal scores were recorded pre- and postoperatively, and subjective questionnaires were completed and foot scan analyses performed at the end of the follow-up period. The mean hallux valgus angle decreased from 38° to 23°, and the mean intermetatarsal angle correction decreased from 17° to 10°. The mean improvement in the American Orthopaedic Foot and Ankle Society hallux metatarsophalangeal-interphalangeal score increased from 52 to 84. Two feet (5.7%) required repeat surgery because of recurrent hallux valgus. No nonunions were identified. Proximal open wedge osteotomy provided satisfactory midterm results in the treatment of severe hallux valgus, with a low complication rate. The potential instability of the first tarsometatarsal joint does not seem to jeopardize the midterm results of the operation. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

The endoscopic ultrasound-assisted Rendez-Vous technique for treatment of recurrent pancreatitis due to pancreas divisum and ansa pancreatica

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Sergio López-Durán

Full Text Available Endoscopic treatment of pancreatic ductal malformations causing recurrent acute pancreatitis, such as pancreas divisum or ansa pancreatica, is mainly based on the sphincterotomy of the minor papilla. However, the technical complexity of conventional endoscopic retrograde cholangiopancreatography (ERCP is increased in patients presenting anatomical variants like these and it may be unsuccessful. We report the case of a pancreas divisum combined with ansa pancreatica and describe the cannulation and sphincterotomy of the minor papilla using an ultrasound-assisted Rendez-Vous technique.

Combined Surgical and Transhepatic Rendezvous Procedure for Relieving Anastomotic Biliary Obstruction in Children with Liver Transplants.

Science.gov (United States)

Crowley, John; Soltys, Kyle; Sindhi, Rakesh; Baskin, Kevin; Yilmaz, Sabri; Close, Orrie; Medsinge, Avinash

2017-08-01

Four children (3 boys and 1 girl, age 1.4-9.4 y) presented 2-70 months after liver transplantation (mean 26 months) with high-grade narrowing at the surgical anastomosis that could not be crossed at percutaneous transhepatic cholangiography. Each patient was treated with a combined surgical and interventional radiology "rendezvous" procedure. Biliary drainage catheters were left in place for an average of 6 months after the procedure. At a mean 7.5 months after biliary drainage catheter removal, all children were catheter-free without clinical or biochemical evidence of biliary stricture recurrence. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

PROXIMITY MANAGEMENT IN CRISIS CONDITIONS

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Ion Dorin BUMBENECI

2010-01-01

Full Text Available The purpose of this study is to evaluate the level of assimilation for the terms "Proximity Management" and "Proximity Manager", both in the specialized literature and in practice. The study has two parts: the theoretical research of the two terms, and an evaluation of the use of Proximity management in 32 companies in Gorj, Romania. The object of the evaluation resides in 27 companies with less than 50 employees and 5 companies with more than 50 employees.

Maximizing the Lifetime of Wireless Sensor Networks Using Multiple Sets of Rendezvous

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Bo Li

2015-01-01

Full Text Available In wireless sensor networks (WSNs, there is a “crowded center effect” where the energy of nodes located near a data sink drains much faster than other nodes resulting in a short network lifetime. To mitigate the “crowded center effect,” rendezvous points (RPs are used to gather data from other nodes. In order to prolong the lifetime of WSN further, we propose using multiple sets of RPs in turn to average the energy consumption of the RPs. The problem is how to select the multiple sets of RPs and how long to use each set of RPs. An optimal algorithm and a heuristic algorithm are proposed to address this problem. The optimal algorithm is highly complex and only suitable for small scale WSN. The performance of the proposed algorithms is evaluated through simulations. The simulation results indicate that the heuristic algorithm approaches the optimal one and that using multiple RP sets can significantly prolong network lifetime.

Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach.

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Own, Chung-Ming; Meng, Zhaopeng; Liu, Kehan

2015-09-03

Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs) and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS), which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach

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Chung-Ming Own

2015-09-01

Full Text Available Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS, which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

Restoring proximal caries lesions conservatively with tunnel restorations

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Chu CH

2013-07-01

Full Text Available Chun-Hung Chu1, May L Mei,1 Chloe Cheung,1 Romesh P Nalliah2 1Faculty of Dentistry, The University of Hong Kong, Hong Kong, People's Republic of China; 2Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA Abstract: The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations. Keywords: operative, practice, tunnel preparation, composite, amalgam, glass ionomer

Echosonography with proximity sensors

International Nuclear Information System (INIS)

Thaisiam, W; Laithong, T; Meekhun, S; Chaiwathyothin, N; Thanlarp, P; Danworaphong, S

2013-01-01

We propose the use of a commercial ultrasonic proximity sensor kit for profiling an altitude-varying surface by employing echosonography. The proximity sensor kit, two identical transducers together with its dedicated operating circuit, is used as a profiler for the construction of an image. Ultrasonic pulses are emitted from one of the transducers and received by the other. The time duration between the pulses allows us to determine the traveling distance of each pulse. In the experiment, the circuit is used with the addition of two copper wires for directing the outgoing and incoming signals to an oscilloscope. The time of flight of ultrasonic pulses can thus be determined. Square grids of 5 × 5 cm 2 are made from fishing lines, forming pixels in the image. The grids are designed to hold the detection unit in place, about 30 cm above a flat surface. The surface to be imaged is constructed to be height varying and placed on the flat surface underneath the grids. Our result shows that an image of the profiled surface can be created by varying the location of the detection unit along the grid. We also investigate the deviation in relation to the time of flight of the ultrasonic pulse. Such an experiment should be valuable for conveying the concept of ultrasonic imaging to physical and medical science undergraduate students. Due to its simplicity, the setup could be made in any undergraduate laboratory relatively inexpensively and it requires no complex parts. The results illustrate the concept of echosonography. (paper)

NASA's Automated Rendezvous and Docking/Capture Sensor Development and Its Applicability to the GER

Science.gov (United States)

Hinkel, Heather; Cryan, Scott; DSouza, Christopher; Strube, Matthew

2014-01-01

This paper will address how a common Automated Rendezvous and Docking/Capture (AR&D/C) sensor suite can support Global Exploration Roadmap (GER) missions, and discuss how the model of common capability development to support multiple missions can enable system capability level partnerships and further GER objectives. NASA has initiated efforts to develop AR&D/C sensors, that are directly applicable to GER. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. NASA's AR&D/C sensor development path could benefit the International Exploration Coordination Group (ISECG) and support the GER mission scenario by providing a common sensor suite upon which GER objectives could be achieved while

Randomized Controlled Trial to Evaluate Splenectomy in Total Gastrectomy for Proximal Gastric Carcinoma.

Science.gov (United States)

Sano, Takeshi; Sasako, Mitsuru; Mizusawa, Junki; Yamamoto, Seiichiro; Katai, Hitoshi; Yoshikawa, Takaki; Nashimoto, Atsushi; Ito, Seiji; Kaji, Masahide; Imamura, Hiroshi; Fukushima, Norimasa; Fujitani, Kazumasa

2017-02-01

To clarify the role of splenectomy in total gastrectomy for proximal gastric cancer. Splenectomy in total gastrectomy is associated with increased operative morbidity and mortality, but its survival benefit is unclear. Previous randomized controlled trials were underpowered and inconclusive. We conducted a multiinstitutional randomized controlled trial. Proximal gastric adenocarcinoma of T2-4/N0-2/M0 not invading the greater curvature was eligible. During the operation, surgeons confirmed that R0 resection was possible with negative lavage cytology, and patients were randomly assigned to either splenectomy or spleen preservation. The primary endpoint was overall survival (OS) and the secondary endpoints were relapse-free survival, operative morbidity, operation time, and blood loss. The trial was designed to confirm noninferiority of spleen preservation to splenectomy in OS with a noninferiority margin of the hazard ratio as 1.21 and 1-sided alpha of 5%. Between June 2002 and March 2009, 505 patients (254 splenectomy, 251 spleen preservation) were enrolled from 36 institutions. Splenectomy was associated with higher morbidity and larger blood loss, but the operation time was similar. The 5-year survivals were 75.1% and 76.4% in the splenectomy and spleen preservation groups, respectively. The hazard ratio was 0.88 (90.7%, confidence interval 0.67-1.16) (splenectomy should be avoided as it increases operative morbidity without improving survival.

Proximal tubular hypertrophy and enlarged glomerular and proximal tubular urinary space in obese subjects with proteinuria.

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Ana Tobar

Full Text Available BACKGROUND: Obesity is associated with glomerular hyperfiltration, increased proximal tubular sodium reabsorption, glomerular enlargement and renal hypertrophy. A single experimental study reported an increased glomerular urinary space in obese dogs. Whether proximal tubular volume is increased in obese subjects and whether their glomerular and tubular urinary spaces are enlarged is unknown. OBJECTIVE: To determine whether proximal tubules and glomerular and tubular urinary space are enlarged in obese subjects with proteinuria and glomerular hyperfiltration. METHODS: Kidney biopsies from 11 non-diabetic obese with proteinuria and 14 non-diabetic lean patients with a creatinine clearance above 50 ml/min and with mild or no interstitial fibrosis were retrospectively analyzed using morphometric methods. The cross-sectional area of the proximal tubular epithelium and lumen, the volume of the glomerular tuft and of Bowman's space and the nuclei number per tubular profile were estimated. RESULTS: Creatinine clearance was higher in the obese than in the lean group (P=0.03. Proteinuria was similarly increased in both groups. Compared to the lean group, the obese group displayed a 104% higher glomerular tuft volume (P=0.001, a 94% higher Bowman's space volume (P=0.003, a 33% higher cross-sectional area of the proximal tubular epithelium (P=0.02 and a 54% higher cross-sectional area of the proximal tubular lumen (P=0.01. The nuclei number per proximal tubular profile was similar in both groups, suggesting that the increase in tubular volume is due to hypertrophy and not to hyperplasia. CONCLUSIONS: Obesity-related glomerular hyperfiltration is associated with proximal tubular epithelial hypertrophy and increased glomerular and tubular urinary space volume in subjects with proteinuria. The expanded glomerular and urinary space is probably a direct consequence of glomerular hyperfiltration. These effects may be involved in the pathogenesis of obesity

Multiple intramedullary nailing of proximal phalangeal fractures of hand

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Patankar Hemant

2008-01-01

Full Text Available Background: Proximal phalangeal fractures are commonly encountered fractures in the hand. Majority of them are stable and can be treated by non-operative means. However, unstable fractures i.e. those with shortening, displacement, angulation, rotational deformity or segmental fractures need surgical intervention. This prospective study was undertaken to evaluate the functional outcome after surgical stabilization of these fractures with joint-sparing multiple intramedullary nailing technique. Materials and Methods: Thirty-five patients with 35 isolated unstable proximal phalangeal shaft fractures of hand were managed by surgical stabilization with multiple intramedullary nailing technique. Fractures of the thumb were excluded. All the patients were followed up for a minimum of six months. They were assessed radiologically and clinically. The clinical evaluation was based on two criteria. 1. total active range of motion for digital functional assessment as suggested by the American Society for Surgery of Hand and 2. grip strength. Results: All the patients showed radiological union at six weeks. The overall results were excellent in all the patients. Adventitious bursitis was observed at the point of insertion of nails in one patient. Conclusion: Joint-sparing multiple intramedullary nailing of unstable proximal phalangeal fractures of hand provides satisfactory results with good functional outcome and fewer complications.

Fractures of the proximal humerus

DEFF Research Database (Denmark)

Brorson, Stig

2013-01-01

Fractures of the proximal humerus have been diagnosed and managed since the earliest known surgical texts. For more than four millennia the preferred treatment was forceful traction, closed reduction, and immobilization with linen soaked in combinations of oil, honey, alum, wine, or cerate......, classification of proximal humeral fractures remains a challenge for the conduct, reporting, and interpretation of clinical trials. The evidence for the benefits of surgery in complex fractures of the proximal humerus is weak. In three systematic reviews I studied the outcome after locking plate osteosynthesis...

Initial outcome and efficacy of S3 proximal humerus locking plate in the treatment of proximal humerus fractures

International Nuclear Information System (INIS)

Zhang Zhiming; Zhu Xuesong; Bao Zhaohua; Yang Huilin

2012-01-01

Objective: to explore the initial outcome and efficacy of S 3 proximal humerus locking plate in the treatment of proximal humerus fractures. Methods: Twenty-two patients with proximal humerus fracture were treated with the S 3 proximal humerus locking plate. Most of the fractures were complex, two-part (n=4), three-part (n=11) and four-part (n=7) fractures according to the Neer classification of the proximal humerus fractures. Results: All patients were followed up for 3∼15 months. There were no complications related to the implant including loosening or breakage of the plate. Good and excellent results were documented in 17 patients fair results in 4 patients according the Neer scores of shoulder. Conclusion: New design concepts of S 3 proximal humerus plate provide the subchondral support and the internal fixation support. With the addition of the proper exercise of the shoulder joint, the outcomes would be satisfied. (authors)

Conversion of Percutaneous Cholecystostomy to Endoscopic Gallbladder Stenting by Using the Rendezvous Technique.

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Nam, Kwangwoo; Choi, Jun-Ho

2017-05-01

We report the successful conversion of percutaneous cholecystostomy (PC) to endoscopic transpapillary gallbladder stenting (ETGS) with insertion of an antegrade guidewire into the duodenum. An 84-year-old man presented with severe acute cholecystitis and septic shock. He had significant comorbidities, and emergent PC was successfully performed. Subsequent ETGS was attempted but unsuccessful owing to difficulties with cystic duct cannulation. However, via the PC tract, the guidewire was passed antegradely into the duodenum, and ETGS with a double-pigtail plastic stent was successfully performed with the rendezvous technique. The PC tube was removed, and no recurrence was reported during the 17-month follow-up period. Conversion of PC to ETGS is a viable option in patients with acute cholecystitis who are not candidates for surgery. Antegrade guidewire insertion via the PC tract may increase the success rate of conversion and decrease the risk of procedure-related complications.

Conversion of Percutaneous Cholecystostomy to Endoscopic Gallbladder Stenting by Using the Rendezvous Technique

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Kwangwoo Nam

2017-05-01

Full Text Available We report the successful conversion of percutaneous cholecystostomy (PC to endoscopic transpapillary gallbladder stenting (ETGS with insertion of an antegrade guidewire into the duodenum. An 84-year-old man presented with severe acute cholecystitis and septic shock. He had significant comorbidities, and emergent PC was successfully performed. Subsequent ETGS was attempted but unsuccessful owing to difficulties with cystic duct cannulation. However, via the PC tract, the guidewire was passed antegradely into the duodenum, and ETGS with a double-pigtail plastic stent was successfully performed with the rendezvous technique. The PC tube was removed, and no recurrence was reported during the 17-month follow-up period. Conversion of PC to ETGS is a viable option in patients with acute cholecystitis who are not candidates for surgery. Antegrade guidewire insertion via the PC tract may increase the success rate of conversion and decrease the risk of procedure-related complications.

Using Information from Rendezvous Missions for Best-Case Appraisals of Impact Damage to Planet Earth Caused by Natural Objects

Science.gov (United States)

Arnold, James O.; Chodas, Paul W.; Ulamec, Stephan; Mathias, Donovan L.; Burkhard, Craig D.

2017-01-01

The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions about potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size range of 160 to 290 m in diameter to be discussed at the PDC 2017 is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) what is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its structure and heterogeneity from the surface and throughout its interior? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as inputs for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, andor cratering. Topics presented in this paper include: (i) the devastation predicted by 2017 PDCs impact on land based on initial observations using ATAPs risk assessment capability, (ii) how information corresponding to items (1) to (3) could be obtained

The impact of trauma on the psyche of the individual using the film Belleville Rendez-vous as an illustrative vehicle.

Science.gov (United States)

Waldron, Sharn

2008-09-01

Using the film Belleville Rendez-vous as a vehicle for discussion, this paper argues that whilst a traumatic complex may bring about dissociation of the psyche, this is not the only possibility, nor is dissociation necessarily to be seen solely as a difficulty to be overcome. If trauma is experienced within the context of support and validation, the experience of trauma may generate integration not only of the trauma but also of the growth potential that the trauma has previously inhibited.

Preliminary study on leadership proximity

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Ghinea Valentina Mihaela

2017-07-01

Full Text Available In general, it is agreed that effective leadership requires a certain degree of proximity, either physical or mental, which enables leaders to maintain control over their followers and communicate their vision. Although we agree with the leadership proximity principles which states that leaders are able to efficiently serve only those people with whom they interact frequently, in this article we focus instead on the disadvantages of being too close and the way in which close proximity can actually hurt the effectiveness of leadership. The main effects that we discuss regard the way in which proximity and familiarity allow followers to see the weaknesses and faults of the leader much more easily and thus diminish the leader’s heroic aura, and the emotional bias that results from a leader being too familiar with his followers which will impede the process of rational decision making. As a result, we argue that there exists a functional proximity which allows the leader the necessary space in which to perform effective identity work and to hide the backstage aspects of leadership, while also allowing him an emotional buffer zone which will enable him to maintain the ability to see clearly and make rational decisions.

PROXIMAL DISABILITY AND SPINAL DEFORMITY INDEX IN PATIENTS WITH PROXIMAL FEMUR FRACTURES

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Sylvio Mistro Neto

2015-12-01

Full Text Available Objective : To evaluate the quality of life related to the spine in patients with proximal femoral fractures. Methods : Study conducted in a tertiary public hospital in patients with proximal femoral fractures caused by low-energy trauma, through the Oswestry Disability Index questionnaire to asses complaints related to the spine at the time of life prior to the femoral fracture. The thoracic and lumbar spine of patients were also evaluated applying the radiographic index described by Gennant (Spinal Deformity Index, which assesses the number and severity of fractures. Results : Seventeen subjects completed the study. All had some degree of vertebral fracture. Patients were classified in the categories of severe and very severe disability in the questionnaire about quality of life. It was found that the higher SDI, the better the quality of life. Conclusion : There is a strong association of disability related to the spine in patients with proximal femoral fracture, and this complaint must be systematically evaluated in patients with appendicular fracture.

Restoring proximal caries lesions conservatively with tunnel restorations.

Science.gov (United States)

Chu, Chun-Hung; Mei, May L; Cheung, Chloe; Nalliah, Romesh P

2013-07-30

The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED) and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations.

High proximal migration in cemented acetabular revisions operated with bone impaction grafting; 47 revision cups followed with RSA for 17 years.

Science.gov (United States)

Mohaddes, Maziar; Herberts, Peter; Malchau, Henrik; Johanson, Per-Erik; Kärrholm, Johan

2017-05-12

Bone impaction grafting is a biologically and mechanically appealing option in acetabular revision surgery, allowing restitution of the bone stock and restoration of the biomechanics. We analysed differences in proximal migration of the revision acetabular components when bone impaction grafting is used together with a cemented or an uncemented cup. 43 patients (47 hips), revised due to acetabular loosening and judged to have less than 50% host bone-implant contact were included. The hips were randomised to either an uncemented (n = 20) or a cemented (n = 27) revision cup. Radiostereometry and radiography was performed postoperatively, at 3 and 6 months, 1, 2, 3, 5, 7, 10 and 13 and 17 years postoperatively. Clinical follow-up was performed at 1, 2 and 5 years postoperatively and thereafter at the same interval as in the radiographic follow-up. There were no differences in the base line demographic data between the 2 groups. At the last follow-up (17 years) 14 hips (10 cemented, 4 uncemented) had been re-revised due to loosening. 3 additional cups (1 uncemented and 2 cemented) were radiographically loose. There was a higher early proximal migration in the cemented cups. Cups operated on with cement showed a higher early migration measured with RSA and also a higher number of late revisions. The reason for this is not known, but factors such as inclusion of cases with severe bone defects, use of smaller bone chips and issues related to the impaction technique might have had various degrees of influence.

Thoracic aortic stent-graft placement combined with left subclavian artery 'chimney operation': therapeutic analysis of 15 cases with insufficient proximal anchor area

International Nuclear Information System (INIS)

Liu Jiayi; Huang Lianjun; Fan Zhanming; Zhang Zhaoqi

2012-01-01

Objective: To discuss the strategies for the management of insufficient proximal anchoring area during the performance of transluminal stent-graft placement (TSGP), and to evaluate the feasibility of intentional coverage of the left subclavian artery (LSA) together with left subclavian artery stent-graft placement by using 'chimney operation' technique. Methods: A total of 15 patients with thoracic aortic diseases complicated by insufficient proximal anchoring area, who were encountered in authors' hospital during the period from Dec. 2009 to April 2011, were enrolled in this study. The clinical data were retrospectively analyzed. The thoracic aortic diseases included aortic dissection (n=6), aortic pseudoaneurysm (n=1), aortic aneurysm (n=4) and penetrating ulcer (n=4). Of the 15 patients, the distance between the lesion and LSA anchoring site 15 mm in 2. TSGP was carried out. The ostium of LSA was intentionally and completely covered by thoracic aortic stent-graft and left subclavian artery stent-graft placement was subsequently performed. The patients were kept under observation for symptoms of cerebral and upper limb ischemia. The postoperative complications such as endoleak and the patency of LSA were assessed with angiography. Results: Thoracic aortic stent-graft placement was successfully carried out in all 15 patients. In addition, one 'chimney' stent was properly implanted in LSA in each patient. After the procedure, no complications of nervous system or severe ischemia of upper extremity occurred. Follow-up examinations performed between 5 days to 3 months after the treatment revealed that the aortic stent-graft remained in stable condition and no type Ⅰ endoleak occurred, meanwhile the blood flow in 'chimney' stent was unobstructed. Conclusion: Intentional LSA coverage with 'chimney operation' can expand the applicability of TSGP with high tolerability. It is especially useful for patients with left vertebral artery blood supply dominance or with

Gunshot Injury of Pelvi-Ureteric Junction: Management by the Rendezvous Technique.

Science.gov (United States)

Sekhon, Virender; Suryavanshi, Manav

2017-01-01

Background: Gunshot injury of ureter is common, but isolated injury of pelvi-ureteric junction (PUJ) has not been reported. Moreover, its management is evolving from the traditional urinary diversion, stenting followed later by definitive surgical repair to a more upfront minimally invasive endourologic approach. Case Presentation: An adolescent boy presented with gunshot laceration injury of left PUJ with associated small intestinal injury. Radiological investigations confirmed a contained urinary leak. Retrograde stenting was not effective. The same guidewire was retained into the urinoma and an antegrade percutaneous access was obtained. A snare was used to retrieve the guidewire and obtain a through and through access. A ureteropelvic drainage catheter was inserted over this guidewire and secured in the upper ureter, bypassing the region of injury. Three weeks later, the drainage tube was removed and the same tract was used for antegrade stenting. A retrograde pyelogram done 3 months later during stent removal demonstrated no leak. The patient is asymptomatic for urinary symptoms on 6 months of follow-up. Conclusion: Rendezvous technique is a feasible alternative to open repair of gunshot pelvi-ureteric junction injury. Long-term follow-up is awaited.

Proximal Probes Facility

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Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

Many-body localization proximity effects in platforms of coupled spins and bosons

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Marino, J.; Nandkishore, R. M.

2018-02-01

We discuss the onset of many-body localization in a one-dimensional system composed of a XXZ quantum spin chain and a Bose-Hubbard model linearly coupled together. We consider two complementary setups, depending whether spatial disorder is initially imprinted on spins or on bosons; in both cases, we explore the conditions for the disordered portion of the system to localize by proximity of the other clean half. Assuming that the dynamics of one of the two parts develops on shorter time scales than the other, we can adiabatically eliminate the fast degrees of freedom, and derive an effective Hamiltonian for the system's remainder using projection operator techniques. Performing a locator expansion on the strength of the many-body interaction term or on the hopping amplitude of the effective Hamiltonian thus derived, we present results on the stability of the many-body localized phases induced by proximity effect. We also briefly comment on the feasibility of the proposed model through modern quantum optics architectures, with the long-term perspective to realize experimentally, in composite open systems, Anderson or many-body localization proximity effects.

Predictive factors for functional outcome and failure in angular stable osteosynthesis of the proximal humerus.

LENUS (Irish Health Repository)

Hardeman, Francois

2012-02-01

Angular stable osteosynthesis has become the gold standard in the operative treatment of proximal humeral fractures. The aim of this article is to determine the indications for osteosynthesis versus primary arthroplasty based on clinical and radiological parameters.

Neighborhoods and manageable proximity

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Stavros Stavrides

2011-08-01

Full Text Available The theatricality of urban encounters is above all a theatricality of distances which allow for the encounter. The absolute “strangeness” of the crowd (Simmel 1997: 74 expressed, in its purest form, in the absolute proximity of a crowded subway train, does not generally allow for any movements of approach, but only for nervous hostile reactions and submissive hypnotic gestures. Neither forced intersections in the course of pedestrians or vehicles, nor the instantaneous crossing of distances by the technology of live broadcasting and remote control give birth to places of encounter. In the forced proximity of the metropolitan crowd which haunted the city of the 19th and 20th century, as well as in the forced proximity of the tele-presence which haunts the dystopic prospect of the future “omnipolis” (Virilio 1997: 74, the necessary distance, which is the stage of an encounter between different instances of otherness, is dissipated.

Digital contrast subtraction radiography for proximal caries diagnosis

International Nuclear Information System (INIS)

Kang, Byung Cheol; Yoon, Suk Ja

2002-01-01

To determine whether subtraction images utilizing contrast media can improve the diagnostic performance of proximal caries diagnosis compared to conventional periapical radiographic images. Thirty-six teeth with 57 proximal surfaces were radiographied using a size no.2 RVG-ui sensor (Trophy Radiology, Marne-la-Vallee, France). The teeth immersed in water-soluble contrast media and subtraction images were taken. Each tooth was then sectioned for histologic examination. The digital radiographic images and subtraction images were examined and interpreted by three dentists for proximal caries. The results of the proximal caries diagnosis were then verified with the results of the histologic examination. The proximal caries sensitivity using digital subtraction radiography was significantly higher than simply examining a single digital radiograph. The sensitivity of the proximal dentinal carious lesion when analyzed with the subtraction radiograph and the radiograph together was higher than with the subtraction radiograph or the radiograph alone. The use of subtraction radiography with contrast media may be useful for detecting proximal dentinal carious lesions.

Calculus Rules for V-Proximal Subdifferentials in Smooth Banach Spaces

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Messaoud Bounkhel

2016-01-01

Full Text Available In 2010, Bounkhel et al. introduced new proximal concepts (analytic proximal subdifferential, geometric proximal subdifferential, and proximal normal cone in reflexive smooth Banach spaces. They proved, in p-uniformly convex and q-uniformly smooth Banach spaces, the density theorem for the new concepts of proximal subdifferential and various important properties for both proximal subdifferential concepts and the proximal normal cone concept. In this paper, we establish calculus rules (fuzzy sum rule and chain rule for both proximal subdifferentials and we prove the Bishop-Phelps theorem for the proximal normal cone. The limiting concept for both proximal subdifferentials and for the proximal normal cone is defined and studied. We prove that both limiting constructions coincide with the Mordukhovich constructions under some assumptions on the space. Applications to nonconvex minimisation problems and nonconvex variational inequalities are established.

[Close reduction combined with minimally invasive percutaneous plate osteosynthesis for proximal and distal tibial fractures: a report of 56 patients].

Science.gov (United States)

Liu, Yin-Wen; Kuang, Yong; Gu, Xin-Feng; Zheng, Yu-Xin; Li, Zhi-Qiang; Wei, Xiao-En; Zhang, Ming-Cai; Zhan, Hong-Sheng; Shi, Yin-yu

2013-03-01

To evaluate the clinical effects of close reduction combined with minimally invasive percutanous plate osteosynthesis (MIPPO) for proximal and distal tibial fractures. From March 2007 to December 2010, 56 patients with proximal and distal tibial fractures were treated with close reduction combined with MIPPO technique. There were 39 males and 17 females,aged from 22 to 67 years with an average of 41.3 years. Left fracture was in 25 cases and right fracture was in 31 cases; proximal tibial fracture was in 15 cases and distal tibial fractures was in 41 cases; 34 cases caused by fall down and 22 cases caused by road accident. The mean time from injury to operation was 1.7 d. Clinical manifestation included pain, swelling of leg with limitation of activity. According to the standard of Johner-Wruhs, clinical effects were evaluated. The mean operative time was 46 min in 56 patients. All fractures obtained satisfactory reduction and the location of plate was good. Incisions healed with one-stage and no superficial or deep infection was found. All the patients were followed up from 8 to 23 months with an average of 14.2 months. Only one fracture complication with delayed union,and after auto grafting with ilium bone,the fracture got union. Other 55 cases obtained bone healing in 15 to 20 weeks after operation and no internal fixation failure was found. The time of walking was 4-6 months after operation,without limping at 7 months after operation. Both lower extremities were symmetrical and the function of knee and ankle got complete recovery. According to the criteria of Johner-Wruhs score,46 cases obtained excellent results,9 good and 2 fair. Treatment of proximal and distal tibial fractures with close reduction and MIPPO technique can not only preserve soft tissue,simplify operative procedure and decrease wound, but also can obtain rigid internal fixation and guarantee early function exercises of knee and ankle joints. The method has the advantages of less soft tissue

Super-Relaxed ( -Proximal Point Algorithms, Relaxed ( -Proximal Point Algorithms, Linear Convergence Analysis, and Nonlinear Variational Inclusions

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Agarwal RaviP

2009-01-01

Full Text Available We glance at recent advances to the general theory of maximal (set-valued monotone mappings and their role demonstrated to examine the convex programming and closely related field of nonlinear variational inequalities. We focus mostly on applications of the super-relaxed ( -proximal point algorithm to the context of solving a class of nonlinear variational inclusion problems, based on the notion of maximal ( -monotonicity. Investigations highlighted in this communication are greatly influenced by the celebrated work of Rockafellar (1976, while others have played a significant part as well in generalizing the proximal point algorithm considered by Rockafellar (1976 to the case of the relaxed proximal point algorithm by Eckstein and Bertsekas (1992. Even for the linear convergence analysis for the overrelaxed (or super-relaxed ( -proximal point algorithm, the fundamental model for Rockafellar's case does the job. Furthermore, we attempt to explore possibilities of generalizing the Yosida regularization/approximation in light of maximal ( -monotonicity, and then applying to first-order evolution equations/inclusions.

Treatment of proximal humerus fractures with locking plates: a systematic review.

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Thanasas, Christos; Kontakis, George; Angoules, Antonios; Limb, David; Giannoudis, Peter

2009-01-01

Locking plates with special configuration for the anatomic region of the proximal humerus have been introduced recently to address the difficulties of stabilizing proximal humeral fractures. The purpose of this study was to carry out a systematic review of the literature on the efficacy and early to medium term functional results of locking plates for stabilization of proximal humeral fractures. Using the PubMed database, a systematic review of the English and German literature was carried out in order to assess the efficacy and complications related to the use of these plates and the patients' functional outcome, using the key words "locking plates proximal humeral fractures," "angular stability plates proximal humeral fractures," "PHILOS plate," and "LPHP plate." Our criteria for eligibility were clinical studies with more than ten cases followed-up, adult patients, and adequate data provided at least in terms of implant related complications. Articles written in English and German language were included. Exclusion criteria were: studies dealing exclusively with 2-part fractures (since this category has a more favorable outcome); experimental studies; case reports; and, literature other than English or German. Each one of the articles was evaluated for quality of the study using the Structured Effectiveness Quality Evaluation Scale (SEQES). Twelve studies including 791 patients met the inclusion criteria. Patients in these studies continued to improve up to one year, achieving a mean Constant score of 74.3. The incidence of the reported complications was: avascular necrosis 7.9%, screw cut-out 11.6% and re-operation rate 13.7%. The high incidence of cut-out may be secondary to the rigidity of the implant in combination with medial inadequate support, in cases compromised by severe underlying osteoporotic bone. Definition of indications for the use of locking plates and attention on technical aspects of applying them would help optimization of the results

Augmented real-time navigation with critical structure proximity alerts for endoscopic skull base surgery.

Science.gov (United States)

Dixon, Benjamin J; Daly, Michael J; Chan, Harley; Vescan, Allan; Witterick, Ian J; Irish, Jonathan C

2014-04-01

Image-guided surgery (IGS) systems are frequently utilized during cranial base surgery to aid in orientation and facilitate targeted surgery. We wished to assess the performance of our recently developed localized intraoperative virtual endoscopy (LIVE)-IGS prototype in a preclinical setting prior to deployment in the operating room. This system combines real-time ablative instrument tracking, critical structure proximity alerts, three-dimensional virtual endoscopic views, and intraoperative cone-beam computed tomographic image updates. Randomized-controlled trial plus qualitative analysis. Skull base procedures were performed on 14 cadaver specimens by seven fellowship-trained skull base surgeons. Each subject performed two endoscopic transclival approaches; one with LIVE-IGS and one using a conventional IGS system in random order. National Aeronautics and Space Administration Task Load Index (NASA-TLX) scores were documented for each dissection, and a semistructured interview was recorded for qualitative assessment. The NASA-TLX scores for mental demand, effort, and frustration were significantly reduced with the LIVE-IGS system in comparison to conventional navigation (P < .05). The system interface was judged to be intuitive and most useful when there was a combination of high spatial demand, reduced or absent surface landmarks, and proximity to critical structures. The development of auditory icons for proximity alerts during the trial better informed the surgeon while limiting distraction. The LIVE-IGS system provided accurate, intuitive, and dynamic feedback to the operating surgeon. Further refinements to proximity alerts and visualization settings will enhance orientation while limiting distraction. The system is currently being deployed in a prospective clinical trial in skull base surgery. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Biomechanical evaluation of straight antegrade nailing in proximal humeral fractures: the rationale of the "proximal anchoring point".

Science.gov (United States)

Euler, Simon A; Petri, Maximilian; Venderley, Melanie B; Dornan, Grant J; Schmoelz, Werner; Turnbull, Travis Lee; Plecko, Michael; Kralinger, Franz S; Millett, Peter J

2017-09-01

Varus failure is one of the most common failure modes following surgical treatment of proximal humeral fractures. Straight antegrade nails (SAN) theoretically provide increased stability by anchoring to the densest zone of the proximal humerus (subchondral zone) with the end of the nail. The aim of this study was to biomechanically investigate the characteristics of this "proximal anchoring point" (PAP). We hypothesized that the PAP would improve stability compared to the same construct without the PAP. Straight antegrade humeral nailing was performed in 20 matched pairs of human cadaveric humeri for a simulated unstable two-part fracture. Biomechanical testing, with stepwise increasing cyclic axial loading (50-N increments each 100 cycles) at an angle of 20° abduction revealed significantly higher median loads to failure for SAN constructs with the PAP (median, 450 N; range, 200-1.000 N) compared to those without the PAP (median, 325 N; range, 100-500 N; p = 0.009). SAN constructs with press-fit proximal extensions (endcaps) showed similar median loads to failure (median, 400 N; range, 200-650 N), when compared to the undersized, commercially available SAN endcaps (median, 450 N; range, 200-600 N; p = 0.240). The PAP provided significantly increased stability in SAN constructs compared to the same setup without this additional proximal anchoring point. Varus-displacing forces to the humeral head were superiorly reduced in this setting. This study provides biomechanical evidence for the "proximal anchoring point's" rationale. Straight antegrade humeral nailing may be beneficial for patients undergoing surgical treatment for unstable proximal humeral fractures to decrease secondary varus displacement and thus potentially reduce revision rates.

A Survey of LIDAR Technology and Its Use in Spacecraft Relative Navigation

Science.gov (United States)

Christian, John A.; Cryan, Scott P.

2013-01-01

This paper provides a survey of modern LIght Detection And Ranging (LIDAR) sensors from a perspective of how they can be used for spacecraft relative navigation. In addition to LIDAR technology commonly used in space applications today (e.g. scanning, flash), this paper reviews emerging LIDAR technologies gaining traction in other non-aerospace fields. The discussion will include an overview of sensor operating principles and specific pros/cons for each type of LIDAR. This paper provides a comprehensive review of LIDAR technology as applied specifically to spacecraft relative navigation. HE problem of orbital rendezvous and docking has been a consistent challenge for complex space missions since before the Gemini 8 spacecraft performed the first successful on-orbit docking of two spacecraft in 1966. Over the years, a great deal of effort has been devoted to advancing technology associated with all aspects of the rendezvous, proximity operations, and docking (RPOD) flight phase. After years of perfecting the art of crewed rendezvous with the Gemini, Apollo, and Space Shuttle programs, NASA began investigating the problem of autonomous rendezvous and docking (AR&D) to support a host of different mission applications. Some of these applications include autonomous resupply of the International Space Station (ISS), robotic servicing/refueling of existing orbital assets, and on-orbit assembly.1 The push towards a robust AR&D capability has led to an intensified interest in a number of different sensors capable of providing insight into the relative state of two spacecraft. The present work focuses on exploring the state-of-the-art in one of these sensors - LIght Detection And Ranging (LIDAR) sensors. It should be noted that the military community frequently uses the acronym LADAR (LAser Detection And Ranging) to refer to what this paper calls LIDARs. A LIDAR is an active remote sensing device that is typically used in space applications to obtain the range to one or more

The three-dimensional assessment of dynamic changes of the proximal segments after intraoral vertical ramus osteotomy.

Science.gov (United States)

Ohba, Seigo; Nakao, Noriko; Awara, Kousuke; Tobita, Takayoshi; Minamizato, Tokutarou; Kawasaki, Takako; Koga, Takamitsu; Nakatani, Yuya; Yoshida, Noriaki; Asahina, Izumi

2015-10-01

The aim of this study was to assess the positional changes of the proximal segments after intraoral vertical ramus osteotomy (IVRO). Fifteen patients underwent IVRO and were followed according to the authors' unique postoperative management regimen. The analyses of the positions and angles of the proximal segments were performed on frontal and lateral cephalograms, which were taken before surgery (T1) and within 3 days (T2), at 4 weeks (T3), and later than 6 months after surgery (T4). The three-dimensional positions of the condylar heads were also assessed by CT images, which were taken before and 1 year after surgery. The proximal segments temporarily swung posteriorly and laterally with a center on the condylar head as a fulcrum point at T2 and T3, compared with T1, and they repositioned at T4. The condylar heads moved inferior approximately 2 mm with lateral rotation one year after surgery, as seen in the CT. The condylar heads changed their positions physiologically for newly established jaw movement after IVRO with the authors' post-operative management regimen because the post-operative skeletal stability and the jaw function were good and stable using this method.

Temperature as a proximate factor in orientation behavior

Energy Technology Data Exchange (ETDEWEB)

Reynolds, W.W.

1977-05-01

Temperature serves as a proximate factor (cue, guidepost, sign stimulus, or directive factor) affecting locomotor responses of fishes. Although temperature can also serve as an ultimate ecological factor, as in behavioral thermoregulation, nonthermal factors may in some cases provide the ultimate adaptive or ecological value of a temperature response; some examples are habitat selection, intraspecific size segregation, interspecific niche differentiation, isolating mechanisms, predator avoidance, prey location, escape reactions, and migrations (thermoperiodic, diel, seasonal, spawning). Conversely, nonthermal variables such as light intensity or water depth may act as accessory proximate factors in thermoregulation. In spawning migrations, thermal requirements of eggs and larvae may take precedence over the (often different) preferenda or optima of adults. Although thermal responses of fishes are largely innate and species specific, ontogenetic and other changes can occur. Since temperature can serve as an unconditioned reinforcer in operant conditioning, thermal responses are not limited to simple kineses or taxes. Nonthermal factors such as photoperiod, circadian rhythms, currents, social and biotic interactions, stresses, infections, or chemicals can affect thermal responses, and may account for some lack of conformity between laboratory preferenda and field distributions and behaviors.

Autonomous, agile micro-satellites and supporting technologies

International Nuclear Information System (INIS)

Breitfeller, E; Dittman, M D; Gaughan, R J; Jones, M S; Kordas, J F; Ledebuhr, A G; Ng, L C; Whitehead, J C; Wilson, B

1999-01-01

This paper updates the on-going effort at Lawrence Livermore National Laboratory to develop autonomous, agile micro-satellites (MicroSats). The objective of this development effort is to develop MicroSats weighing only a few tens of kilograms, that are able to autonomously perform precision maneuvers and can be used telerobotically in a variety of mission modes. The required capabilities include satellite rendezvous, inspection, proximity-operations, docking, and servicing. The MicroSat carries an integrated proximity-operations sensor-suite incorporating advanced avionics. A new self-pressurizing propulsion system utilizing a miniaturized pump and non-toxic mono-propellant hydrogen peroxide was successfully tested. This system can provide a nominal 25 kg MicroSat with 200-300 m/s delta-v including a warm-gas attitude control system. The avionics is based on the latest PowerPC processor using a CompactPCI bus architecture, which is modular, high-performance and processor-independent. This leverages commercial-off-the-shelf (COTS) technologies and minimizes the effects of future changes in processors. The MicroSat software development environment uses the Vx-Works real-time operating system (RTOS) that provides a rapid development environment for integration of new software modules, allowing early integration and test. We will summarize results of recent integrated ground flight testing of our latest non-toxic pumped propulsion MicroSat testbed vehicle operated on our unique dynamic air-rail

[Epidemiology, treatment and results of proximal humeral fractures: experience of a district hospital in a sports- and tourism area].

Science.gov (United States)

Sonderegger, J; Simmen, H-P

2003-02-01

The epidemiology, therapy and results of proximal humeral fractures in a touristic area were investigated and our concept for treatment presented. Between 1.1.1999 and 30.04.2000 adult patients with proximal humeral fractures were included, the fractures classified (Codman/Neer and AO) and results determined after an average of 9 months. 62 adults were treated. 59 (95 %) had an accident during leisure time, mainly skiing accidents (52 %). 7 patients (11 %) had an associated luxation of the shoulder. 51 (82 %) were treated conservatively, 11 (18 %) operatively with a T-plate. The conservatively treated had to wear a Gilchrist-cast for an average of 29 (operatively 13) days, started passive movement after 20 (operatively 9) days, and active movement after 44 (operatively 45) days. The 32 employed (52 %) were not able to work for 46 days on average. Overall, 52 patients (84 %) were totally or mostly satisfied with the result. 5 among the 13 patients (38.5 %) with 3- or 4-part-fractures, and 4 among the 11 operated patients (36.4 %) were not satisfied with the result. Proximal humeral fractures are common skiing injuries, they need a long and intensive treatment and are economically expensive. The Codman/Neer and AO-classifications are equal. The results for simple, mainly conservatively treated fractures (Codman/Neer 1, 2A, 2-part) are good. Complex, mainly operatively treated fractures (Codman/Neer 3- and 4-part) have a much poorer prognosis. Diagnostically the computed tomography with 3-D-reconstruction is recommended for a better representation of the fracture and a safer choice of the therapeutical strategy.

Sliding-screw plate fixation of proximal femoral fractures: Radiographic assessment

Energy Technology Data Exchange (ETDEWEB)

Sartoris, D.J.; Resnick, D.; Kerr, R.; Goergen, T.

1985-07-01

The sliding compression screw-sideplate combination is currently the most widely employed device for internal fixation of stable and unstable intertrochanteric fractures of the femur. The normal and abnormal radiographic appearances of this device in the immediate post-operative period are discussed. Potential long-term complications including mal- or non-union, intra-articular penetration, metal failure, rotation of the proximal fracture fragment, disengagement, trochanteric bursitis, leg length discrepancy, delayed cervical stress fracture, and ischemic necrosis are reviewed.

Sliding-screw plate fixation of proximal femoral fractures: Radiographic assessment

International Nuclear Information System (INIS)

Sartoris, D.J.; Resnick, D.; California Univ., San Diego, La Jolla; Kerr, R.; Goergen, T.

1985-01-01

The sliding compression screw-sideplate combination is currently the most widely employed device for internal fixation of stable and unstable intertrochanteric fractures of the femur. The normal and abnormal radiogrpahic appearances of this device in the immediate post-operative period are discussed. Potential long-term complications including mal- or non-union, intra-articular penetration, metal failure, rotation of the proximal fracture fragment, disengagement, trochanteric bursitis, leg length discrepancy, delayed cervical stress fracture, and ischemic necrosis are reviewed. (orig.)

Giant proximity effect in ferromagnetic bilayers

Science.gov (United States)

Ramos, Silvia; Charlton, Tim; Quintanilla, Jorge; Suter, Andreas; Moodera, Jagadeesh; Prokscha, Thomas; Salman, Zaher; Forgan, Ted

2013-03-01

The proximity effect is a phenomenon where an ordered state leaks from a material into an adjacent one over some finite distance, ξ. For superconductors, this distance is ~ the coherence length. Nevertheless much longer-range, ``giant'' proximity effects have been observed in cuprate junctions. This surprising effect can be understood as a consequence of critical opalescence. Since this occurs near all second order phase transitions, giant proximity effects should be very general and, in particular, they should be present in magnetic systems. The ferromagnetic proximity effect has the advantage that its order parameter (magnetization) can be observed directly. We investigate the above phenomenon in Co/EuS bilayer films, where both materials undergo ferromagnetic transitions but at rather different temperatures (bulk TC of 1400K for Co and 16.6K for EuS). A dramatic increase in the range of the proximity effect is expected near the TC of EuS. We present the results of our measurements of the magnetization profiles as a function of temperature, carried out using the complementary techniques of low energy muon rotation and polarized neutron reflectivity. Work supported by EPSRC, STFC and ONR grant N00014-09-1-0177 and NSF grant DMR 0504158.

Failed Surgical Management of Acute Proximal Fifth Metatarsal (Jones) Fractures: A Retrospective Case Series and Literature Review.

Science.gov (United States)

Granata, Jaymes D; Berlet, Gregory C; Philbin, Terrence M; Jones, Grant; Kaeding, Christopher C; Peterson, Kyle S

2015-12-01

Nonunion, delayed union, and refracture after operative treatment of acute proximal fifth metatarsal fractures in athletes is uncommon. This study was a failure analysis of operatively managed acute proximal fifth metatarsal fractures in healthy athletes. We identified 149 patients who underwent operative treatment for fifth metatarsal fractures. Inclusion criteria isolated skeletally mature, athletic patients under the age of 40 with a minimum of 1-year follow-up. Patients were excluded with tuberosity fractures, fractures distal to the proximal metaphyseal-diaphyseal region of the fifth metatarsal, multiple fractures or operative procedures, fractures initially treated conservatively, and medical comorbidities/risk factors for nonunion. Fifty-five patients met the inclusion/exclusion criteria. Four (7.3%) patients required a secondary operative procedure due to refracture. The average time to refracture was 8 months. All refractures were associated with bent screws and occurred in male patients who participated in professional basketball, professional volleyball, and college football. The average time for release to progressive weight-bearing was 6 weeks. Three patients were revised to a bigger size screw and went on to union. One patient was revised to the same-sized screw and required a second revision surgery for nonunion. All failures were refractures in competitive athletes who were initially treated with small diameter solid or cannulated stainless steel screws. The failures were not associated with early postoperative weight-bearing protocol. Maximizing initial fixation stiffness may decrease the late failure rate in competitive athletes. More clinical studies are needed to better understand risk factors for failure after screw fixation in the competitive, athletic population. Prognostic, Level IV: Case series. © 2015 The Author(s).

Quantum Proximity Resonances

International Nuclear Information System (INIS)

Heller, E.J.

1996-01-01

It is well known that at long wavelengths λ an s-wave scatterer can have a scattering cross section σ on the order of λ 2 , much larger than its physical size, as measured by the range of its potential. Very interesting phenomena can arise when two or more identical scatterers are placed close together, well within one wavelength. We show that, for a pair of identical scatterers, an extremely narrow p-wave open-quote open-quote proximity close-quote close-quote resonance develops from a broader s-wave resonance of the individual scatterers. A new s-wave resonance of the pair also appears. The relation of these proximity resonances (so called because they appear when the scatterers are close together) to the Thomas and Efimov effects is discussed. copyright 1996 The American Physical Society

Fibulectomy for primary proximal fibular bone tumors: A functional and clinical outcome in 46 patients

Directory of Open Access Journals (Sweden)

Zile Singh Kundu

2018-01-01

Full Text Available Background: Primary benign and malignant tumors of the proximal fibula are not very common. Upper fibula being an expendable bone; the majority of the primary bone tumors at this site are usually treated with en bloc proximal fibulectomy. There is scarce literature on functional results, difficulties faced during dissection when to preserve or sacrifice common peroneal nerve and importance of lateral collateral ligament repair after proximal fibulectomy. The present study attempts at assessing these variables. Materials and Methods: This retrospective study included 46 patients; 30 males and 16 females with age ranging from 12 to 44 years (average: 26 years operated between 2003 and 2014. There were 34 benign and 12 malignant tumors. All were treated with proximal en bloc fibulectomy as indicated and decided by the operating surgeon keeping in view its extent on magnetic resonance imaging. Peroneal nerve sacrifice or preservation was decided as per the type (benign/malignant, its involvement by the tumor and the extent of the tumor. In 14 (for 12 malignant and two benign giant cell tumors [GCTs] patients, the peroneal nerve required resection for the margins. Partial upper tibial resection was performed in cases of malignant tumors and three GCTs. The followup ranged between 24 and 120 months (median: 48 months. Results: Patients with peroneal nerve resection had inferior functional outcome than those without peroneal nerve resection. There was no higher risk of tibia fracture in patients with partial tibial resection. Lateral collateral reconstruction yielded better results and should be performed in all cases. Functional outcome was significantly better in patients with benign tumors than in patients with malignant tumors as these required neither resection of the peroneal nerve nor large amount of muscle excision. The functional results were evaluated using Musculoskeletal Tumor Society (MSTS score, and clinical outcomes were evaluated using

Early results for treatment of two- and three-part fractures of the proximal humerus using Contours PHP (proximal humeral plate).

Science.gov (United States)

Biazzo, Alessio; Cardile, Carlo; Brunelli, Luca; Ragni, Paolo; Clementi, Daniele

2017-04-28

The management of displaced 2- and 3-part fractures of the proximal humerus is controversial, both in younger and in elderly patients. The purpose of this paper is to evaluate the functional results of the Contours Proximal Humerus Plate (OrthofixR, Bussolengo,Verona, Italy), for the treatment of displaced 2- and 3-part fractures of the proximal humerus. We retrospectively reviewed 55 patients with proximal humerus fractures, who underwent osteosynthesis with Contours Proximal Humerus Plate from December 2011 to March 2015. We had 21 patients with 2-part fractures and with an average age of 67.1 years and 34 patients with 3-part fractures, with average age of 63.6 years. The average union time was 3 months. The mean Constant score was 67 for 2-part fracture group and 64.9 for 3-part fracture group. The difference was not statistically significant (p = 0.18). The overall complication rate was 14.5 %. Six patients underwent additional surgery (10.9%). The most frequent major complication was secondary loss of reduction following varus collapse of the fracture (2 cases). In these patients, there was loss of medial hinge integrity due to impaction and osteoporosis. The placement of the main locking screw in the calcar area to provide inferomedial support is the rational of the Contours Proximal Humerus Plate. Osteosynthesis with Contours Proximal Humerus Plate is a safe system for treating displaced 2- and 3-part fractures of the proximal humerus, with good functional results and complication rates comparable to those reported in the literature.

Robust adaptive backstepping neural networks control for spacecraft rendezvous and docking with input saturation.

Science.gov (United States)

Xia, Kewei; Huo, Wei

2016-05-01

This paper presents a robust adaptive neural networks control strategy for spacecraft rendezvous and docking with the coupled position and attitude dynamics under input saturation. Backstepping technique is applied to design a relative attitude controller and a relative position controller, respectively. The dynamics uncertainties are approximated by radial basis function neural networks (RBFNNs). A novel switching controller consists of an adaptive neural networks controller dominating in its active region combined with an extra robust controller to avoid invalidation of the RBFNNs destroying stability of the system outside the neural active region. An auxiliary signal is introduced to compensate the input saturation with anti-windup technique, and a command filter is employed to approximate derivative of the virtual control in the backstepping procedure. Globally uniformly ultimately bounded of the relative states is proved via Lyapunov theory. Simulation example demonstrates effectiveness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Hypospadias repair: Byar's two stage operation revisited.

Science.gov (United States)

Arshad, A R

2005-06-01

Hypospadias is a congenital deformity characterised by an abnormally located urethral opening, that could occur anywhere proximal to its normal location on the ventral surface of glans penis to the perineum. Many operations had been described for the management of this deformity. One hundred and fifteen patients with hypospadias were treated at the Department of Plastic Surgery, Hospital Kuala Lumpur, Malaysia between September 1987 and December 2002, of which 100 had Byar's procedure performed on them. The age of the patients ranged from neonates to 26 years old. Sixty-seven patients had penoscrotal (58%), 20 had proximal penile (18%), 13 had distal penile (11%) and 15 had subcoronal hypospadias (13%). Operations performed were Byar's two-staged (100), Bracka's two-staged (11), flip-flap (2) and MAGPI operation (2). The most common complication encountered following hypospadias surgery was urethral fistula at a rate of 18%. There is a higher incidence of proximal hypospadias in the Malaysian community. Byar's procedure is a very versatile technique and can be used for all types of hypospadias. Fistula rate is 18% in this series.

Influence of surgeon's experience and supervision on re-operation rate after hip fracture surgery

DEFF Research Database (Denmark)

Palm, Henrik; Jacobsen, Steffen; Krasheninnikoff, Michael

2006-01-01

rehabilitation programme, between 2002 and 2004. Re-operation rate was assessed 6 months postoperatively. Surgeons were grouped as unsupervised junior registrars versus experienced surgeons operating or supervising. Fractures were stratified as technically undemanding or demanding. RESULTS: Unsupervised junior......OBJECTIVE: To investigate the influence of the performing surgeon's experience and degree of supervision on re-operation rate among patients admitted with a proximal femoral fracture (PFF). METHODS: Prospective study of 600 consecutive patients with proximal femoral fracture in our multimodal...... registrars operated on 23% (137/600) of all and 15% (56/365) of technically demanding proximal femoral fractures. The latter had a higher re-operation rate within 6 months, compared with the rate when more experienced surgeons were present. In logistic regression analysis combining age, gender, American...

Proximal Hamstring Tendinosis and Partial Ruptures.

Science.gov (United States)

Startzman, Ashley N; Fowler, Oliver; Carreira, Dominic

2017-07-01

Proximal hamstring tendinosis and partial hamstring origin ruptures are painful conditions of the proximal thigh and hip that may occur in the acute, chronic, or acute on chronic setting. Few publications exist related to their diagnosis and management. This systematic review discusses the incidence, treatment, and prognosis of proximal hamstring tendinosis and partial hamstring ruptures. Conservative treatment measures include nonsteroidal anti-inflammatory drugs, physical therapy, rest, and ice. If these measures fail, platelet-rich plasma or shockwave therapy may be considered. When refractory to conservative management, these injuries may be treated with surgical debridement and hamstring reattachment. [Orthopedics. 2017; 40(4):e574-e582.]. Copyright 2017, SLACK Incorporated.

A review of cooperative and uncooperative spacecraft pose determination techniques for close-proximity operations

Science.gov (United States)

Opromolla, Roberto; Fasano, Giancarmine; Rufino, Giancarlo; Grassi, Michele

2017-08-01

The capability of an active spacecraft to accurately estimate its relative position and attitude (pose) with respect to an active/inactive, artificial/natural space object (target) orbiting in close-proximity is required to carry out various activities like formation flying, on-orbit servicing, active debris removal, and space exploration. According to the specific mission scenario, the pose determination task involves both theoretical and technological challenges related to the search for the most suitable algorithmic solution and sensor architecture, respectively. As regards the latter aspect, electro-optical sensors represent the best option as their use is compatible with mass and power limitation of micro and small satellites, and their measurements can be processed to estimate all the pose parameters. Overall, the degree of complexity of the challenges related to pose determination largely varies depending on the nature of the targets, which may be actively/passively cooperative, uncooperative but known, or uncooperative and unknown space objects. In this respect, while cooperative pose determination has been successfully demonstrated in orbit, the uncooperative case is still under study by universities, research centers, space agencies and private companies. However, in both the cases, the demand for space applications involving relative navigation maneuvers, also in close-proximity, for which pose determination capabilities are mandatory, is significantly increasing. In this framework, a review of state-of-the-art techniques and algorithms developed in the last decades for cooperative and uncooperative pose determination by processing data provided by electro-optical sensors is herein presented. Specifically, their main advantages and drawbacks in terms of achieved performance, computational complexity, and sensitivity to variability of pose and target geometry, are highlighted.

Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis Following Segmental Posterior Spinal Instrumentation and Fusion; Minimum 2 Years Follow-Up

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Mohammad Khaki Nahad

2009-11-01

Full Text Available Background:To evaluate proximal junctional segment changes in Adolescent Idiopathic Scoliosis(AIS the posterior spinal fusion and also instrumentation also and finding of probable risk factors, were all considered in this study.Methods: We retrospectively reviewed radiographs of 121 consecutive patients who underwent posterior spinal fusion for AIS from T3 or below, with a mean follow-   up of 32.8 months(range,24-83. All coronal and sagittal measurements including the proximal junctional kyphosis (PJKangle recorded on standing anteroposterior and lateral radiographs preoperative, early postoperative and on follow-up radiographs.The data were analyzed using the Spss 10.0 software.Dependent(paired samples student t-test was used for analysis between the groups Results: There was PJK angle above normal for the same junctional segment preoperatively in 13 patients (10.7% and the incidence of the PJK postoperatively was   7.4% (9 patients, 7 female and 2 male, all detected until 2 years postoperation.The mean increase in the PJK angle from pre-operation until 6 weeks postoperation was 5.9° (range,0-13°(P=0.02 and until 2 years post operation was 14.3° (range, 2- 16°(p=0.000.The mean proximal junctional angle increased 1.6° until 2 years postoperation in non-PJK group(n=112.Conclusion: The prevalence of Proximal Junctional Kyphosis was low and a silent radiographic problem. In some cases is preventable with perfect pre-operative planning. There is no specific demographic or radiographic variables or instrumentation types associated with developing PJK .

Robotics in hostile environment I. S. I. S. robot - automatic positioning and docking with proximity and force feed back sensors

Energy Technology Data Exchange (ETDEWEB)

Gery, D

1987-01-01

Recent improvements in control command systems and the development of tactile proximity and force feed back sensors make it possible to robotize complex inspection and maintenance operations in hostile environment, which could have not been possible by classical remotely operated manipulators. We describe the I.S.I.S. robot characteristics, the control command system software principles and the tactile and force-torque sensors which have been developed for the different sequences of an hostile environment inspection and repair: access trajectories generation with obstacles shunning, final positioning and docking using parametric algorithms taking into account measurement of the end of arm proximity and force-torque sensors.

Combined application of distal and proximal embolic protection devices in endovascular stenting for severe carotid artery stenosis

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Zhi-hua DU

2011-09-01

Full Text Available Objective To analyze and summarize methods and experiences of combined application of distal and proximal embolic protection devices(EPD in endovascular stenting for severe carotid artery stenosis.Methods Five patients with severe stenosis of the common carotid artery or with extracranial segment of the internal carotid artery diagnosed through digital subtraction angiography(DSA from March to July 2010 were involved in the present study.All patients received carotid angioplasty and stenting(CAS,with a combination of distal and proximal EPD via the percutaneous femoral artery approach.Results The operation failed in one patient,whereas technical success with no intraoperative complication was achieved in four patients.The symptoms disappeared or improved in the four cases that achieved technical success.The follow-up duration was one to three months,and no cerebral ischemia was found.Conclusion CAS with the combined application of distal and proximal EPD in some special cases of carotid artery stenosis may surmount the shortage of single EPD,reduce the risk of intraoperative embolization,decrease the time of intraoperative endovascular inflow occlusion,and reduce high-risk operations.CAS may be used as an individualized treatment strategy for patients with carotid artery stenosis.

Proximal Participation: A Pathway into Work

Science.gov (United States)

Chan, Selena

2013-01-01

In a longitudinal case study of apprentices, the term proximal participation was coined to describe the entry process of young people, with unclear career destinations, into the trade of baking. This article unravels the significance of proximal participation in the decision-making processes of young people who enter a trade through initial…

Proximal Humerus Fractures: Evaluation and Management in the Elderly Patient

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Grawe, Brian

2018-01-01

Introduction: Proximal humerus fractures are common in the elderly. The evaluation and management of these injuries is often controversial. The purpose of this study is to review recent evidence and provide updated recommendations for treating proximal humerus fractures in the elderly. Methods: A literature review of peer-reviewed publications related to the evaluation and management of proximal humerus fractures in the elderly was performed. There was a focus on randomized controlled trials and systematic reviews published within the last 5 years. Results: The incidence of proximal humerus fractures is increasing. It is a common osteoporotic fracture. Bone density is a predictor of reduction quality and can be readily assessed with anteroposterior views of the shoulder. Social independence is a predictor of outcome, whereas age is not. Many fractures are minimally displaced and respond acceptably to nonoperative management. Displaced and severe fractures are most frequently treated operatively with intramedullary nails, locking plates, percutaneous techniques, or arthroplasty. Discussion: Evidence from randomized controlled trials and systematic reviews is insufficient to recommend a treatment; however, most techniques have acceptable or good outcomes. Evaluation should include an assessment of the patient’s bone quality, social independence, and surgical risk factors. With internal fixation, special attention should be paid to medial comminution, varus angulation, and restoration of the calcar. With arthroplasty, attention should be paid to anatomic restoration of the tuberosities and proper placement of the prosthesis. Conclusion: A majority of minimally displaced fractures can be treated conservatively with early physical therapy. Treatment for displaced fractures should consider the patient’s level of independence, bone quality, and surgical risk factors. Fixation with percutaneous techniques, intramedullary nails, locking plates, and arthroplasty are all

Posttraumatic Proximal Radioulnar Synostosis after Closed Reduction for a Radial Neck and Olecranon Fracture

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Patrick R. Keller

2018-01-01

Full Text Available Posttraumatic proximal radioulnar synostosis (PPRUS is a severe complication of radial head and neck fractures known to occur after severe injury or operative fixation. Cases of PPRUS occurring after minimally displaced, nonoperatively treated radial neck injuries are, by contrast, extremely rare. Here, we present a pediatric case of PPRUS that developed after a nonoperatively treated minimally displaced radial neck fracture with concomitant olecranon fracture. While more cases are needed to establish the association between this pattern of injury and PPRUS, we recommend that when encountering patients with a minimally displaced radial neck fracture and a concomitant elbow injury, the rare possibility of developing proximal radioulnar synostosis should be considered.

Ultimate and proximate explanations of strong reciprocity.

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Vromen, Jack

2017-08-23

Strong reciprocity (SR) has recently been subject to heated debate. In this debate, the "West camp" (West et al. in Evol Hum Behav 32(4):231-262, 2011), which is critical of the case for SR, and the "Laland camp" (Laland et al. in Science, 334(6062):1512-1516, 2011, Biol Philos 28(5):719-745, 2013), which is sympathetic to the case of SR, seem to take diametrically opposed positions. The West camp criticizes advocates of SR for conflating proximate and ultimate causation. SR is said to be a proximate mechanism that is put forward by its advocates as an ultimate explanation of human cooperation. The West camp thus accuses advocates of SR for not heeding Mayr's original distinction between ultimate and proximate causation. The Laland camp praises advocates of SR for revising Mayr's distinction. Advocates of SR are said to replace Mayr's uni-directional view on the relation between ultimate and proximate causes by the bi-directional one of reciprocal causation. The paper argues that both the West camp and the Laland camp misrepresent what advocates of SR are up to. The West camp is right that SR is a proximate cause of human cooperation. But rather than putting forward SR as an ultimate explanation, as the West camp argues, advocates of SR believe that SR itself is in need of ultimate explanation. Advocates of SR tend to take gene-culture co-evolutionary theory as the correct meta-theoretical framework for advancing ultimate explanations of SR. Appearances notwithstanding, gene-culture coevolutionary theory does not imply Laland et al.'s notion of reciprocal causation. "Reciprocal causation" suggests that proximate and ultimate causes interact simultaneously, while advocates of SR assume that they interact sequentially. I end by arguing that the best way to understand the debate is by disambiguating Mayr's ultimate-proximate distinction. I propose to reserve "ultimate" and "proximate" for different sorts of explanations, and to use other terms for distinguishing

Prosthetic replacement for proximal humeral fractures.

Science.gov (United States)

Kontakis, George; Tosounidis, Theodoros; Galanakis, Ioannis; Megas, Panagiotis

2008-12-01

The ideal management of complex proximal humeral fractures continues to be debatable. Evolution of proximal humeral fracture management, during the past decade, led to the implementation of many innovations in surgical treatment. Even though the pendulum of treatment seems to swing towards new trends such as locked plating, hemiarthroplasty remains a valid and reliable option that serves the patient's needs well. Hemiarthroplasty is indicated for complex proximal humeral fractures in elderly patients with poor bone stock and when internal fixation is difficult or unreliable. Hemiarthroplasty provides a better result when it is performed early post-injury. Stem height, retroversion and tuberosity positioning are technical aspects of utmost importance. Additionally reverse total shoulder arthroplasty is an alternative new modality that can be used as a primary solution in selected patients with proximal humeral fracture treatment. Failed hemiarthroplasty and fracture sequelae can be successfully managed with reverse total shoulder arthroplasty. Individual decision-making and tailored treatment that takes into consideration the personality of the fracture and the patient's characteristics should be used.

Treatment of unstable trochanteric fractures. Randomised comparison of the gamma nail and the proximal femoral nail.

NARCIS (Netherlands)

Schipper, I.B.; Steyerberg, E.W.; Castelein, R.M.; Heijden, F.H. van der; Hoed, P.T. den; Kerver, A.J.; Vugt, A.B. van

2004-01-01

The proximal femoral nail (PFN) is a recently introduced intramedullary system, designed to improve treatment of unstable trochanteric fractures of the hip. In a multicentre prospective clinical study, the intra-operative use, complications and outcome of treatment using the PFN (n = 211) were

Locking plate fixation for proximal humerus fractures.

LENUS (Irish Health Repository)

Burke, Neil G

2012-02-01

Locking plates are increasingly used to surgically treat proximal humerus fractures. Knowledge of the bone quality of the proximal humerus is important. Studies have shown the medial and dorsal aspects of the proximal humeral head to have the highest bone strength, and this should be exploited by fixation techniques, particularly in elderly patients with osteoporosis. The goals of surgery for proximal humeral fractures should involve minimal soft tissue dissection and achieve anatomic reduction of the head complex with sufficient stability to allow for early shoulder mobilization. This article reviews various treatment options, in particular locking plate fixation. Locking plate fixation is associated with a high complication rate, such as avascular necrosis (7.9%), screw cutout (11.6%), and revision surgery (13.7%). These complications are frequently due to the varus deformation of the humeral head. Strategic screw placement in the humeral head would minimize the possibility of loss of fracture reduction and potential hardware complications. Locking plate fixation is a good surgical option for the management of proximal humerus fractures. Complications can be avoided by using better bone stock and by careful screw placement in the humeral head.

Proximal collagenous gastroenteritides:

DEFF Research Database (Denmark)

Nielsen, Ole Haagen; Riis, Lene Buhl; Danese, Silvio

2014-01-01

AIM: While collagenous colitis represents the most common form of the collagenous gastroenteritides, the collagenous entities affecting the proximal part of the gastrointestinal tract are much less recognized and possibly overlooked. The aim was to summarize the latest information through a syste...

Promoting proximal formative assessment with relational discourse

Science.gov (United States)

Scherr, Rachel E.; Close, Hunter G.; McKagan, Sarah B.

2012-02-01

The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

Influence of surgeon's experience and supervision on re-operation rate after hip fracture surgery

DEFF Research Database (Denmark)

Palm, Henrik; Jacobsen, Steffen; Krasheninnikoff, Michael

2006-01-01

OBJECTIVE: To investigate the influence of the performing surgeon's experience and degree of supervision on re-operation rate among patients admitted with a proximal femoral fracture (PFF). METHODS: Prospective study of 600 consecutive patients with proximal femoral fracture in our multimodal...... Society of Anaesthesiologists score, New Mobility Score, time to surgery and type of implant, surgery by unsupervised junior registrars was still a significant independent risk factor for re-operation in technically demanding proximal femoral fractures. CONCLUSION: Unsupervised junior registrars should...

Psychological responses to the proximity of climate change

Science.gov (United States)

Brügger, Adrian; Dessai, Suraje; Devine-Wright, Patrick; Morton, Thomas A.; Pidgeon, Nicholas F.

2015-12-01

A frequent suggestion to increase individuals' willingness to take action on climate change and to support relevant policies is to highlight its proximal consequences, that is, those that are close in space and time. But previous studies that have tested this proximizing approach have not revealed the expected positive effects on individual action and support for addressing climate change. We present three lines of psychological reasoning that provide compelling arguments as to why highlighting proximal impacts of climate change might not be as effective a way to increase individual mitigation and adaptation efforts as is often assumed. Our contextualization of the proximizing approach within established psychological research suggests that, depending on the particular theoretical perspective one takes on this issue, and on specific individual characteristics suggested by these perspectives, proximizing can bring about the intended positive effects, can have no (visible) effect or can even backfire. Thus, the effects of proximizing are much more complex than is commonly assumed. Revealing this complexity contributes to a refined theoretical understanding of the role that psychological distance plays in the context of climate change and opens up further avenues for future research and for interventions.

Critical Proximity as a Methodological Move in Techno-Anthropology

DEFF Research Database (Denmark)

Birkbak, Andreas; Petersen, Morten Krogh; Elgaard Jensen, Torben

2015-01-01

proximity.’ Critical proximity offers an alternative to critical distance, especially with respect to avoiding premature references to abstract panoramas such as democratization and capitalist exploitation in the quest to conduct ‘critical’ analysis. Critical proximity implies, instead, granting the beings...

Identifying indications for percutaneous (PTC) vs. endoscopic ultrasound (EUS)- guided "rendezvous" procedure in biliary obstruction and incomplete endoscopic retrograde cholangiography (ERC).

Science.gov (United States)

Albert, J G; Finkelmeier, F; Friedrich-Rust, M; Kronenberger, B; Trojan, J; Zeuzem, S; Sarrazin, C

2014-10-01

The variety of rendezvous (RV) procedures has recently been extended by EUS- and PTCD-guided procedures as a complementary means to conventional ERCP. We have identified indication criteria and the potential of biliary PTCD-guided vs. EUS-guided RV. Consecutive patients with bile duct obstruction who underwent RV were included. In all, ERCP alone was unable to achieve treatment success. Indication, technical success, and outcome in PTCD- vs. EUS-guided RV were retrospectively compared to identify criteria that indicate preference of RV technique. Site of obstruction, clinical scenario (stenosis with abscess vs. no abscess) and reason for previous failure of ERC were evaluated. In 32 patients, three different indications for RV procedures were identified: First, a one-step access to assist in failed ERCP (type 1, intra-ductal RV); second, temporary drainage for prolonged treatment of complex biliary disease (type 2, intra-ductal RV), and drainage of cholangio-abscess with re-establishing bile outflow (type 3, intra-abscess RV). Indication of PTCD- vs. EUS-guided rendezvous was competitive in type 1, but exclusive in favor of PTCD in types 2 and 3. The site of biliary obstruction indicated the anatomic location of RV procedures. This classification may help to define inclusion criteria for prospective studies on biliary RV procedures. Choice of therapeutic strategy depends on the anatomic location of the biliary obstruction and the type of the biliary lesion. PTCD-guided RV might improve outcome in cholangio-abscess. © Georg Thieme Verlag KG Stuttgart · New York.

Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique.

Science.gov (United States)

Patrzyk, Maciej; Dierzek, Przemyslaw; Glitsch, Anne; Paul, Hartmut; Heidecke, Claus-Dieter

2015-01-01

Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique) approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ½ year observation period.

Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings

Science.gov (United States)

Bates, David M.

2016-01-01

NASA's Cassini Spacecraft, launched on October 15th, 1997 which arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004–08), and has since been approved for a first and second extended mission through 2017. As part of the final extended missions, Cassini will begin an aggressive and exciting campaign of high inclination, low altitude flybys within the inner most rings of Saturn, skimming Saturn’s outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, requires a strategy for managing the Sun Sensor Assembly (SSA) health, the details of which are presented in this paper.

Proximal methods for the resolution of inverse problems: application to positron emission tomography

International Nuclear Information System (INIS)

Pustelnik, N.

2010-12-01

The objective of this work is to propose reliable, efficient and fast methods for minimizing convex criteria, that are found in inverse problems for imagery. We focus on restoration/reconstruction problems when data is degraded with both a linear operator and noise, where the latter is not assumed to be necessarily additive.The reliability of the method is ensured through the use of proximal algorithms, the convergence of which is guaranteed when a convex criterion is considered. Efficiency is sought through the choice of criteria adapted to the noise characteristics, the linear operators and the image specificities. Of particular interest are regularization terms based on total variation and/or sparsity of signal frame coefficients. As a consequence of the use of frames, two approaches are investigated, depending on whether the analysis or the synthesis formulation is chosen. Fast processing requirements lead us to consider proximal algorithms with a parallel structure. Theoretical results are illustrated on several large size inverse problems arising in image restoration, stereoscopy, multi-spectral imagery and decomposition into texture and geometry components. We focus on a particular application, namely Positron Emission Tomography (PET), which is particularly difficult because of the presence of a projection operator combined with Poisson noise, leading to highly corrupted data. To optimize the quality of the reconstruction, we make use of the spatio-temporal characteristics of brain tissue activity. (author)

Infiltrating/sealing proximal caries lesions

DEFF Research Database (Denmark)

Martignon, S; Ekstrand, K R; Gomez, J

2012-01-01

This randomized split-mouth controlled clinical trial aimed at assessing the therapeutic effects of infiltration vs. sealing for controlling caries progression on proximal surfaces. Out of 90 adult students/patients assessed at university clinics and agreeing to participate, 39, each with 3...... differences in lesion progression between infiltration and placebo (P = 0.0012) and between sealing and placebo (P = 0.0269). The study showed that infiltration and sealing are significantly better than placebo treatment for controlling caries progression on proximal lesions. No significant difference...

Proximal femoral fractures

DEFF Research Database (Denmark)

Palm, Henrik; Teixidor, Jordi

2015-01-01

searched the homepages of the national heath authorities and national orthopedic societies in West Europe and found 11 national or regional (in case of no national) guidelines including any type of proximal femoral fracture surgery. RESULTS: Pathway consensus is outspread (internal fixation for un...

Manned maneuvering unit applications for automated rendezvous and capture

Science.gov (United States)

Brehm, Donald L.; Cuseo, John A.; Lenda, Joseph A.; Ray, Lex; Whitsett, C. Edward

Automated Rendezvous and Capture (AR&C) is an important technology to multiple National Aeronautics and Space Administration (NASA) programs and centers. The recent Johnson Spacecraft Center (JSC) AR&C Quality Function Deployment (QFD) has listed on-orbit demonstration of related technologies as a near term priority. Martin Marietta has been evaluating use of the Manned Maneuvering Unit (MMU) for a low cost near term on-orbit demonstration of AR&C technologies such as control algorithms, sensors, and processors as well as system level performance. The MMU Program began in 1979 as the method of repairing the Space Shuttle (STS) Thermal Protection System (the tiles). The units were not needed for this task, but were successfully employed during three Shuttle flights in 1984: a test flight was flown in in February as proof of concept, in April the MMU participated in the Solar Max Repair Mission, and in November the MMU's returned to space to successfully rescue the two errant satellites, Westar and Palapa. In the intervening years, the MMU simulator and MMU Qualification Test Unit (QTU) have been used for Astronaut training and experimental evaluations. The Extra-Vehicular Activities (EVA) Retriever has used the QTU, in an unmanned form, as a free-flyer on the Johnson Space Center (JSC) Precision Air Bearing Floor (PABF). Currently, the MMU is undergoing recertification for flight. The two flight units were removed from storage in September, 1991 and evaluation tests were performed. The tests demonstrated that the units are in good shape with no discrepancies that would preclude further use. The Return to Flight effort is currently clearing up recertification issues and evaluating the design against the present Shuttle environments.

Spontaneous Rupture of Superficial Femoral Artery Repaired with Endovascular Stent-Grafting with use of Rendez-Vous Technique, Followed by Delayed Infection

International Nuclear Information System (INIS)

Fanelli, Fabrizio; Cannavale, Alessandro; Gazzetti, Marianna; Fantozzi, Cristiano; Taurino, Maurizio; Speziale, Francesco

2013-01-01

This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient’s clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

Spontaneous Rupture of Superficial Femoral Artery Repaired with Endovascular Stent-Grafting with use of Rendez-Vous Technique, Followed by Delayed Infection

Energy Technology Data Exchange (ETDEWEB)

Fanelli, Fabrizio, E-mail: fabrizio.fanelli@uniroma1.it; Cannavale, Alessandro [University of Rome ' Sapienza,' , Department of Radiological Sciences, Vascular and Interventional Radiology Unit (Italy); Gazzetti, Marianna [Sapienza University of Rome ' Sapienza,' , Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy); Fantozzi, Cristiano; Taurino, Maurizio [University of Rome ' Sapienza,' , Department of Vascular Surgery (Italy); Speziale, Francesco [Sapienza University of Rome ' Sapienza,' , Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy)

2013-02-15

This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient's clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

Performance of RVGui sensor and Kodak Ektaspeed Plus film for proximal caries detection.

Science.gov (United States)

Abreu, M; Mol, A; Ludlow, J B

2001-03-01

A high-resolution charge-coupled device was used to compare the diagnostic performances obtained with Trophy's new RVGui sensor and Kodak Ektaspeed Plus film with respect to caries detection. Three acquisition modes of the Trophy RVGui sensor were compared with Kodak Ektaspeed Plus film. Images of the proximal surfaces of 40 extracted posterior teeth were evaluated by 6 observers. The presence or absence of caries was scored by means of a 5-point confidence scale. The actual caries status of each surface was determined through ground-section histology. Responses were evaluated by means of receiver operating characteristic analysis. Areas under receiver operating characteristic curves (A(Z)) were assessed through analysis of variance. The mean A(Z) scores were 0.85 for film, 0.84 for the high-resolution caries mode, and 0.82 for both the low resolution caries mode and the high-resolution periodontal mode. These differences were not statistically significant (P =.70). The differences among observers also were not statistically significant (P =.23). The performance of the RVGui sensor in high- and low-resolution modes for proximal caries detection is comparable to that of Ektaspeed Plus film.

Proximity correction of high-dosed frame with PROXECCO

Science.gov (United States)

Eisenmann, Hans; Waas, Thomas; Hartmann, Hans

1994-05-01

Usefulness of electron beam lithography is strongly related to the efficiency and quality of methods used for proximity correction. This paper addresses the above issue by proposing an extension to the new proximity correction program PROXECCO. The combination of a framing step with PROXECCO produces a pattern with a very high edge accuracy and still allows usage of the fast correction procedure. Making a frame with a higher dose imitates a fine resolution correction where the coarse part is disregarded. So after handling the high resolution effect by means of framing, an additional coarse correction is still needed. Higher doses have a higher contribution to the proximity effect. This additional proximity effect is taken into account with the help of the multi-dose input of PROXECCO. The dose of the frame is variable, depending on the deposited energy coming from backscattering of the proximity. Simulation proves the very high edge accuracy of the applied method.

Dual pathology proximal median nerve compression of the forearm.

LENUS (Irish Health Repository)

Murphy, Siun M

2013-12-01

We report an unusual case of synchronous pathology in the forearm- the coexistence of a large lipoma of the median nerve together with an osteochondroma of the proximal ulna, giving rise to a dual proximal median nerve compression. Proximal median nerve compression neuropathies in the forearm are uncommon compared to the prevalence of distal compression neuropathies (eg Carpal Tunnel Syndrome). Both neural fibrolipomas (Refs. 1,2) and osteochondromas of the proximal ulna (Ref. 3) in isolation are rare but well documented. Unlike that of a distal compression, a proximal compression of the median nerve will often have a definite cause. Neural fibrolipoma, also called fibrolipomatous hamartoma are rare, slow-growing, benign tumours of peripheral nerves, most often occurring in the median nerve of younger patients. To our knowledge, this is the first report of such dual pathology in the same forearm, giving rise to a severe proximal compression of the median nerve. In this case, the nerve was being pushed anteriorly by the osteochondroma, and was being compressed from within by the intraneural lipoma. This unusual case highlights the advantage of preoperative imaging as part of the workup of proximal median nerve compression.

Giant proximity effect and critical opalescence in EuS

Science.gov (United States)

Charlton, Timothy; Ramos, Silvia; Quintanilla, Jorge; Suter, Andreas; Moodera, Jagadeesh

2015-03-01

The proximity effect is a type of wetting phenomenon where an ordered state, usually magnetism or superconductivity, ``leaks'' from one material into an adjacent one over some finite distance. For superconductors, the characteristic range is of the order of the coherence length, usually hundreds of nm. Nevertheless much longer, ``giant'' proximity effects have been observed in cuprate perovskite junctions. Such giant proximity effects can be understood by taking into account the divergence of the pairing susceptibility in the non-superconducting material when it is itself close to a superconducting instability: a superconducting version of critical opalescence. Since critical opalescence occurs in all second order phase transitions, giant proximity effects are expected to be general, therefor there must be a giant ferromagnetic proximity effect. Compared to its superconducting counterpart, the giant ferromagnetic proximity effect has the advantage that the order parameter (magnetization) can be observed directly. We have fabricated Co/EuS thin films and measured the magnetization profiles as a function of temperature using the complementary techniques of low energy muon relaxation and polarized neutron reflectivity. Details of the proximity effect near TCEuS will be presented.

Motor-evacuatory gastric function in patients with duodenal cancer after selective proximal vagotomy

Energy Technology Data Exchange (ETDEWEB)

Aliev, M A; Kabdrakhmanov, T K; Kashkin, K A; Darmenov, O K; Kuspangaljeva, Sh U [Kazakhskij Inst. Klinicheskoj i Ehksperimental' noj Khirurgii Minzdrava Kazakhskoj SSR, Alma-Ata

1983-06-01

Motor-evacuatory stomach function by using continuous radiogastrography was studied in patients with duodenal ulcers. Radiogastrograms were analyzed before operation, on the 7th-15th day after selective proximal vagotomy performed either independently or in combination with draining operations. A faster evacuation of food from the stomach prevailed in an uncomplicated form of duodenal ulcer and compensated stenosis of the pyloroduodenal zone, evacuatory stomach function was retarded or absent in subcompensated and decompensated stenosis. Discoordinated gastric peristalsis and a reverse food input were noted in patients with subcompensated stenosis. At early time after operations temporary inhibition of evacuatory stomach function occurred in 94.2% of the patients; it could be corrected with conservative therapeutic measures.

Motor-evacuatory gastric function in patients with duodenal cancer after selective proximal vagotomy

International Nuclear Information System (INIS)

Aliev, M.A.; Kabdrakhmanov, T.K.; Kashkin, K.A.; Darmenov, O.K.; Kuspangaljeva, Sh.U.

1983-01-01

Motor-evacuatory stomach function by using continuous radiogastrography was studied in patients with duodenal ulcers. Radiogastrograms were analyzed before operation, on the 7th-15th day after selective proximal vagotomy performed either independently or in combination with draining operations. A faster evacuation of food from the stomach prevailed in an uncomplicated form of duodenal ulcer and compensated stenosis of the pyloroduodenal zone, evacuatory stomach function was retarded or absent in subcompensated and decompensated stenosis. Discoordinated gastric peristalsis and a reverse food input were noted in patients with subcompensated stenosis. At early time after operations temporary inhibition of evacuatory stomach function occurred in 94.2% of the patients; it could be corrected with conservative therapeutic measures

Strong Proximities on Smooth Manifolds and Vorono\\" i Diagrams

OpenAIRE

Peters, J. F.; Guadagni, C.

2015-01-01

This article introduces strongly near smooth manifolds. The main results are (i) second countability of the strongly hit and far-miss topology on a family $\\mathcal{B}$ of subsets on the Lodato proximity space of regular open sets to which singletons are added, (ii) manifold strong proximity, (iii) strong proximity of charts in manifold atlases implies that the charts have nonempty intersection. The application of these results is given in terms of the nearness of atlases and charts of proxim...

Contingency Operations of Americas Next Moon Rocket, Ares V

Science.gov (United States)

Jaap, John; Richardson, Lea

2010-01-01

America has begun the development of a new space vehicle system which will enable humans to return to the moon and reach even farther destinations. The system is called Constellation: it has 2 earth-launch vehicles, Ares I and Ares V; a crew module, Orion; and a lander, Altair with descent and ascent stages. Ares V will launch an Earth Departure Stage (EDS) and Altair into low earth orbit. Ares I will launch the Orion crew module into low earth orbit where it will rendezvous and dock with the Altair and EDS "stack". After rendezvous, the stack will contain four complete rocket systems, each capable of independent operations. Of course this multiplicity of vehicles provides a multiplicity of opportunities for off-nominal behavior and multiple mitigation options for each. Contingency operations are complicated by the issues of crew safety and the possibility of debris from the very large components impacting the ground. This paper examines contingency operations of the EDS in low earth orbit, during the boost to translunar orbit, and after the translunar boost. Contingency operations under these conditions have not been a consideration since the Apollo era and analysis of the possible contingencies and mitigations will take some time to evolve. Since the vehicle has not been designed, much less built, it is not possible to evaluate contingencies from a root-cause basis or from a probability basis; rather they are discussed at an effects level (such as the reaction control system is consuming propellant at a high rate). Mitigations for the contingencies are based on the severity of the off-nominal condition, the time of occurrence, recovery options, options for alternate missions, crew safety, evaluation of the condition (forensics) and future prevention. Some proposed mitigations reflect innovation in thinking and make use of the multiplicity of on-orbit resources including the crew; example: Orion could do a "fly around" to allow the crew to determine the condition

Spacecraft Actuator Diagnosis with Principal Component Analysis: Application to the Rendez-Vous Phase of the Mars Sample Return Mission

Directory of Open Access Journals (Sweden)

Othman Nasri

2015-01-01

Full Text Available This paper presents a fault detection and isolation (FDI approach in order to detect and isolate actuators (thrusters and reaction wheels faults of an autonomous spacecraft involved in the rendez-vous phase of the Mars Sample Return (MSR mission. The principal component analysis (PCA has been adopted to estimate the relationships between the various variables of the process. To ensure the feasibility of the proposed FDI approach, a set of data provided by the industrial “high-fidelity” simulator of the MSR and representing the opening (resp., the rotation rates of the spacecraft thrusters (resp., reaction wheels has been considered. The test results demonstrate that the fault detection and isolation are successfully accomplished.

Locking internal fixator with minimally invasive plate osteosynthesis for the proximal and distal tibial fractures

Directory of Open Access Journals (Sweden)

TONG Da-ke

2012-02-01

Full Text Available 【Abstract】Objective: To investigate the efficacy of the locking internal fixator (LIF, which includes the locking compression plate (LCP and the less invasive stable system (LISS, in the proximal and distal tibial fractures. Methods: We did a retrospective study on a total of 98 patients with either proximal or distal tibial fractures from January 2003 to January 2007, who had received the opera- tion with LIF by the minimally invasive plate osteosynthesis (MIPO technique. The data consisted of 43 proximal tibial fractures (type AO41C3 and 55 distal tibial fractures (type AO43C3. Results: No complications were observed in all patients after operation. The mean healing time was 8.4 months (range 5-14 months. Only two cases of delayed union occurred at postoperative 10 months. No infections were reported after the definitive surgery even in the cases of open fractures. All patients reached a full range of motion at postoperative 6 to 9 months and regained the normal functions of knee and ankle joints. Conclusion: Using LIF in MIPO technique is a reliable approach towards the proximal and distal tibial fractures that are not suitable for intramedullary nailing. Key words: Internal fixator; Tibial fractures; Fracture fixation, intramedullary; Bone plates

75 FR 5009 - Proximity Detection Systems for Underground Mines

Science.gov (United States)

2010-02-01

... Proximity Detection Systems for Underground Mines AGENCY: Mine Safety and Health Administration, Labor... information regarding whether the use of proximity detection systems would reduce the risk of accidents where... . Information on MSHA-approved proximity detection systems is available on the Internet at http://www.msha.gov...

[Partial replantation following proximal limb injury].

Science.gov (United States)

Dubert, T; Malikov, S A; Dinh, A; Kupatadze, D D; Oberlin, C; Alnot, J Y; Nabokov, B B

2000-11-01

Proximal replantation is a technically feasible but life-threatening procedure. Indications must be restricted to patients in good condition with a good functional prognosis. The goal of replantation must be focused not only on reimplanting the amputated limb but also on achieving a good functional outcome. For the lower limb, simple terminalization remains the best choice in many cases. When a proximal amputation is not suitable for replantation, the main aim of the surgical procedure must be to reconstruct a stump long enough to permit fitting a prosthesis preserving the function of the adjacent joint. If the proximal stump beyond the last joint is very short, it may be possible to restore some length by partial replantation of spared tissues from the amputated part. We present here the results we obtained following this policy. This series included 16 cases of partial replantations, 14 involving the lower limb and 2 the upper limb. All were osteocutaneous microsurgical transfers. For the lower limb, all transfers recovered protective sensitivity following tibial nerve repair. The functional calcaeoplantar unit was used in 13 cases. The transfer of this specialized weight bearing tissue provided a stable distal surface making higher support unnecessary. In one case, we raised a 13-cm vascularized tibial segment covered with foot skin for additional length. For the upper limb, the osteocutaneous transfer, based on the radial artery, was not reinnervated, but this lack of sensitivity did not impair prosthesis fitting. One vascular failure was finally amputated. This was the only unsuccessful result. For all other patients, the surgical procedure facilitated prosthesis fitting and preserved the proximal joint function despite an initially very proximal amputation. The advantages of partial replantation are obvious compared with simple terminalization or secondary reconstruction. There is no secondary donor site and, because there is no major muscle mass in the

Finite Element Modelling of a Field-Sensed Magnetic Suspended System for Accurate Proximity Measurement Based on a Sensor Fusion Algorithm with Unscented Kalman Filter.

Science.gov (United States)

Chowdhury, Amor; Sarjaš, Andrej

2016-09-15

The presented paper describes accurate distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic model was derived with the Finite Element Modelling approach. The advantage of such modelling is a more accurate dynamic model parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for accurate proximity measurement of the magnetic object. The paper successively presents a modelling procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation.

Proximity functions for general right cylinders

International Nuclear Information System (INIS)

Kellerer, A.M.

1981-01-01

Distributions of distances between pairs of points within geometrical objects, or the closely related proximity functions and geometric reduction factors, have applications to dosimetric and microdosimetric calculations. For convex bodies these functions are linked to the chord-length distributions that result from random intersections by straight lines. A synopsis of the most important relations is given. The proximity functions and related functions are derived for right cylinders with arbitrary cross sections. The solution utilizes the fact that the squares of the distances between two random points are sums of independently distributed squares of distances parallel and perpendicular to the axis of the cylinder. Analogous formulas are derived for the proximity functions or geometric reduction factors for a cylinder relative to a point. This requires only a minor modification of the solution

Correction of Hallux Valgus Interphalangeus With an Osteotomy of the Distal End of the Proximal Phalanx (Distal Akin Osteotomy).

Science.gov (United States)

Vander Griend, Robert

2017-02-01

Operative correction of a symptomatic hallux valgus interphalangeus (HVI) deformity is often achieved with an osteotomy at the proximal end of the proximal phalanx (Akin osteotomy). However, the apex of the typical HVI deformity (center of rotation angle) is at the interphalangeal joint of the hallux. This study was done to evaluate the results of performing a medial closing wedge osteotomy at the distal end of the proximal phalanx. Thirty-three patients (33 feet) underwent an osteotomy at the distal end of the proximal phalanx for correction of HVI. All of the patients had other forefoot deformities which were corrected at the same time. Eight of these were revision procedures of prior forefoot operations. The length of follow-up was determined by the associated procedures with a minimum follow-up of 4 months. The preoperative hallux valgus interphalangeus angle averaged 16 degrees of valgus (range 7-32 degrees) and was corrected to an average of 2 degrees of valgus (range 5 degrees valgus to 5 degrees varus). All of the patients were satisfied with the postoperative appearance and function of the first toe. Because of simultaneous correction of numerous other forefoot problems, it was not possible to specifically isolate or evaluate the effects and benefits of this osteotomy using outcomes measures. There was one intraoperative complication resulting in a fracture extending into the adjacent IP joint. Correction of an HVI deformity can be achieved with an osteotomy at the distal end of the proximal phalanx. This was a safe technique with few complications and with good results in terms of both correction and patient satisfaction. Level IV, retrospective case series.

Combined Radial-Pedal Access Strategy and Radial-Pedal Rendezvous in the Revascularization of Complex Total Occlusions of the Superficial Femoral Artery (the "No Femoral Access" Strategy).

Science.gov (United States)

Hanna, Elias B; Prout, Davey L

2016-04-01

To describe the combined use of radial-pedal access for recanalization of complex superficial femoral artery (SFA) occlusions unsuitable for transfemoral recanalization. Patients are selected for this strategy if they have a long (≥ 10 cm) SFA occlusion with unfavorable aortoiliac anatomy, an absent ostial stump, or severely diseased and calcified distal reconstitution. Left radial artery and distal anterior or posterior tibial artery are accessed with 6-F and 4-F sheaths, respectively. The SFA lesion is crossed retrogradely with a 0.035-inch wire system. If retrograde crossing is not immediately successful, transradial subintimal tracking and radial-pedal subintimal rendezvous are used to allow retrograde reentry. Fifteen patients (mean age 62 ± 5 years; 11 men) have been treated in this fashion, and frequently stented, through the tibiopedal access. Seven patients required radial-pedal rendezvous to facilitate retrograde reentry. Two patients underwent transradial iliac stenting during the same session, and 1 patient underwent transradial kissing angioplasty of the profunda. No major complication occurred in any patient. After the procedure, the pulse across the accessed tibial artery was palpable in all patients. In patients with long and complex SFA occlusion unsuitable for transfemoral recanalization, a radial-pedal strategy can overcome revascularization obstacles. © The Author(s) 2016.

Proximity effect at Millikelvin temperatures

International Nuclear Information System (INIS)

Mota, A.C.

1986-01-01

Proximity effects have been studied extensively for the past 25 years. Typically, they are in films several thousand angstroms thick at temperatures not so far below T/sub CNS/, the transition temperature of the NS system. Interesting is, however, the proximity effect at temperatures much lower than T/sub CNS/. In this case, the Cooper-pair amplitudes are not small and very long pair penetration lengths into the normal metal can be expected. Thus, we have observed pair penetration lengths. For these investigations very suitable specimens are commercial wires of one filament of NbTi or Nb embedded in a copper matrix. The reasons are the high transmission coefficient at the interface between the copper and the superconductor and the fact that the copper in these commercial wires is rather clean with electron free paths between 5 to 10 μm long. In this paper, the magnetic properties of thick proximity systems in the range of temperatures between T/sub CNS/ and 5 x 10/sup -4/ T/sub CNS/ in both low and high magnetic fields are discussed

Basic targeting strategies for rendezvous and flyby missions to the near-Earth asteroids

Science.gov (United States)

Perozzi, Ettore; Rossi, Alessandro; Valsecchi, Giovanni B.

2001-01-01

Missions to asteroids and comets are becoming increasingly feasible both from a technical and a financial point of view. In particular, those directed towards the Near-Earth Asteroids have proven suitable for a low-cost approach, thus attracting the major space agencies as well as private companies. The choice of a suitable target involves both scientific relevance and mission design considerations, being often a difficult task to accomplish due to the limited energy budget at disposal. The aim of this paper is to provide an approach to basic trajectory design which allows to account for both aspects of the problem, taking into account scientific and technical information. A global characterization of the Near-Earth Asteroids population carried out on the basis of their dynamics, physical properties and flight dynamics considerations, allows to identify a group of candidates which satisfy both, the scientific and engineering requirements. The feasibility of rendezvous and flyby missions towards them is then discussed and the possibility of repeated encounters with the same object is investigated, as an intermediate scenario. Within this framework, the capability of present and near future launch and propulsion systems for interplanetary missions is also addressed.

A microcontroller-based compensated optical proximity detector employing the switching-mode synchronous detection technique

International Nuclear Information System (INIS)

Rakshit, Anjan; Chatterjee, Amitava

2012-01-01

This paper describes the development of a microcontroller-based optical proximity detector that can provide a low-cost yet powerful obstacle-sensing mechanism for mobile robots. The system is developed with the switching-mode synchronous detection technique to provide satisfactory performance over a wide range of operating conditions and is developed with the facility of externally setting a threshold, for reliable operation. The system is dynamically compensated against ambient illumination variations. Experimental studies demonstrate how the minimum distance of activation can be varied with different choices of thresholds. (paper)

Dual pathology proximal median nerve compression of the forearm.

Science.gov (United States)

Murphy, Siun M; Browne, Katherine; Tuite, David J; O'Shaughnessy, Michael

2013-12-01

We report an unusual case of synchronous pathology in the forearm- the coexistence of a large lipoma of the median nerve together with an osteochondroma of the proximal ulna, giving rise to a dual proximal median nerve compression. Proximal median nerve compression neuropathies in the forearm are uncommon compared to the prevalence of distal compression neuropathies (eg Carpal Tunnel Syndrome). Both neural fibrolipomas (Refs. 1,2) and osteochondromas of the proximal ulna (Ref. 3) in isolation are rare but well documented. Unlike that of a distal compression, a proximal compression of the median nerve will often have a definite cause. Neural fibrolipoma, also called fibrolipomatous hamartoma are rare, slow-growing, benign tumours of peripheral nerves, most often occurring in the median nerve of younger patients. To our knowledge, this is the first report of such dual pathology in the same forearm, giving rise to a severe proximal compression of the median nerve. In this case, the nerve was being pushed anteriorly by the osteochondroma, and was being compressed from within by the intraneural lipoma. This unusual case highlights the advantage of preoperative imaging as part of the workup of proximal median nerve compression. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique

Directory of Open Access Journals (Sweden)

Maciej Patrzyk

2015-01-01

Full Text Available Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ΍ year observation period.

Effect of age on proximal esophageal response to swallowing

Directory of Open Access Journals (Sweden)

Roberto Oliveira Dantas

2010-12-01

Full Text Available CONTEXT: It has been demonstrated that the ageing process affects esophageal motility. OBJECTIVES: To evaluate the effect of the age on the proximal esophageal response to wet swallows. METHOD: We measured the proximal esophageal response to swallows of a 5 mL bolus of water in 69 healthy volunteers, 20 of them aged 18-30 years (group I, 27 aged 31-50 years (group II, and 22 aged 51-74 years (group III. We used the manometric method with continuous perfusion. The proximal esophageal contractions were recorded 5 cm from a pharyngeal recording site located 1 cm above the upper esophageal sphincter. The time between the onset of the pharyngeal and of the proximal esophageal recording (pharyngeal-esophageal time and the amplitude, duration and area under the curve of the proximal esophageal contraction were measured. RESULTS: The pharyngeal-esophageal time was shorter in group I subjects than in group II and III subjects (P<0.05. The duration of proximal esophageal contractions was longer in group I than in groups II and III (P<0.001. There was no differences between groups in the amplitude or area under the curve of contractions. There were no differences between groups II and III for any of the measurements. CONCLUSION: We conclude that the age may affects the response of the proximal esophagus to wet swallows.

Performance of a proximity cryogenic system for the ATLAS central solenoid magnet

CERN Document Server

Doi, Y; Makida, Y; Kondo, Y; Kawai, M; Aoki, K; Haruyama, T; Kondo, T; Mizumaki, S; Wachi, Y; Mine, S; Haug, F; Delruelle, N; Passardi, Giorgio; ten Kate, H H J

2002-01-01

The ATLAS central solenoid magnet has been designed and constructed as a collaborative work between KEK and CERN for the ATLAS experiment in the LHC project The solenoid provides an axial magnetic field of 2 Tesla at the center of the tracking volume of the ATLAS detector. The solenoid is installed in a common cryostat of a liquid-argon calorimeter in order to minimize the mass of the cryostat wall. The coil is cooled indirectly by using two-phase helium flow in a pair of serpentine cooling line. The cryogen is supplied by the ATLAS cryogenic plant, which also supplies helium to the Toroid magnet systems. The proximity cryogenic system for the solenoid has two major components: a control dewar and a valve unit In addition, a programmable logic controller, PLC, was prepared for the automatic operation and solenoid test in Japan. This paper describes the design of the proximity cryogenic system and results of the performance test. (7 refs).

Laparoendoscopic Rendezvous for Concomitant Cholecystocholedocholithiasis: A Successful Modality Even in the Most Difficult Presentations Including Pregnancy.

Science.gov (United States)

Shirah, Bader Hamza; Mikwar, Zaher Abdulaziz; Ahmad, Akram Neyaz; Dahlan, Yaser Mohammed

2016-01-01

Background . Laparoendoscopic rendezvous (LERV) technique is emerging as an attractive treatment option for concomitant cholecystocholedocholithiasis. In this paper, we report our experience in performing the LERV technique in patients with unusual presentations in terms of anatomical difficulty, pregnancy, multiple comorbid diseases, and postlaparotomy. We aim to highlight the effectiveness of the LERV technique in some clinical situations where conventional methods would fail or carry high risks in adequately managing concomitant cholecystocholedocholithiasis. Methods . Four patients diagnosed to have concomitant cholecystocholedocholithiasis with associated difficult presentation or comorbid diseases were treated using the LERV technique. One patient presented with difficult anatomy where ERCP failed at initial attempts. Another patient was pregnant (first trimester). A third patient had complex comorbid diseases (bronchial asthma, hypertension, congestive heart failure, and end-stage renal disease on regular hemodialysis). A fourth patient had previous laparotomy and sigmoidectomy for diverticular disease and had severe hospital phobia. Results . All patients tolerated the LERV technique very well; no intraoperative occurrence was reported. The mean operative time was 86.3 ± 17.2 minutes; mean time of the endoscopic part was 29.4 ± 3.57 minutes. The mean blood loss was 44.3 ± 18.2 mL (range 20-85). Residual stone, postoperative complications, postoperative morbidity, and postoperative mortality were 0 (0%). Postoperative short hospital stay was reported in all patients, average 3 days (range 2-4). Conclusion . LERV procedure is a safe and effective treatment option for the management of concomitant cholecystocholedocholithiasis, even in difficult situations where other methods would fail or carry high risks, or in patients presenting with severe comorbid diseases or pregnancy. This procedure may emerge as an attractive alternative option for high

OSIRIS-REx Touch-And-Go (TAG) Navigation Performance

Science.gov (United States)

Berry, Kevin; Antreasian, Peter; Moreau, Michael C.; May, Alex; Sutter, Brian

2015-01-01

The Origins Spectral Interpretation Resource identification Security Regolith Explorer (OSIRIS-REx) mission is a NASA New Frontiers mission launching in 2016 to rendezvous with the near-Earth asteroid (101955) Bennu in late 2018. Following an extensive campaign of proximity operations activities to characterize the properties of Bennu and select a suitable sample site, OSIRIES-REx will fly a Touch-And-Go (TAG) trajectory to the asteroid's surface to obtain a regolith sample. The paper summarizes the mission design of the TAG sequence, the propulsive required to achieve the trajectory, and the sequence of events leading up to the TAG event. The paper will summarize the Monte-Carlo simulation of the TAG sequence and present analysis results that demonstrate the ability to conduct the TAG within 25 meters of the selected sample site and +-2 cms of the targeted contact velocity. The paper will describe some of the challenges associated with conducting precision navigation operations and ultimately contacting a very small asteroid.

OSIRI-REx Touch and Go (TAG) Navigation Performance

Science.gov (United States)

Berry, Kevin; Antreasian, Peter; Moreau, Michael C.; May, Alex; Sutter, Brian

2015-01-01

The Origins Spectral Interpretation Resource Identification Security Regolith Explorer (OSIRIS-REx) mission is a NASA New Frontiers mission launching in 2016 to rendezvous with the near-Earth asteroid (101955) Bennu in late 2018. Following an extensive campaign of proximity operations activities to characterize the properties of Bennu and select a suitable sample site, OSIRIS-REx will fly a Touch-And-Go (TAG) trajectory to the asteroid's surface to obtain a regolith sample. The paper summarizes the mission design of the TAG sequence, the propulsive maneuvers required to achieve the trajectory, and the sequence of events leading up to the TAG event. The paper also summarizes the Monte-Carlo simulation of the TAG sequence and presents analysis results that demonstrate the ability to conduct the TAG within 25 meters of the selected sample site and 2 cm/s of the targeted contact velocity. The paper describes some of the challenges associated with conducting precision navigation operations and ultimately contacting a very small asteroid.

The value of different imaging methods on classification in displaced proximal humeral fractures

International Nuclear Information System (INIS)

Cai Jingyu; Zhu Qingsheng

2004-01-01

Objective: To investigate the influence of common X-ray, two-dimensional computed tomography (2D-CT), spiral computed tomography (SCT), and three-dimensional (3-D) reconstruction on the classification in displaced proximal humeral fractures. Methods: Three groups were divided on the basis of various imaging methods, including group A (common X-ray), group B (common X-ray and 2D-CT), and group C (3-D reconstruction of SCT and 2D-SCT). 46 cases of displaced proximal humeral fractures were classified with Neer system. The true rate of fracture classification by use of three methods was compared with each other, and clinical significance of SCT and 3-D reconstruction was evaluated. Results: Based on operation, 46 cases of displaced proximal humeral fractures in group A included 26 cases of Neer two-part fractures, 13 cases of three-part fractures, and 7 cases of four-part fractures. The true cases of common X-ray were 22 in Neer two-part fractures and 8 in three and four-part fractures, there was significant difference between Neer two-part fractures and Neer three and four-part fractures (P<0.05); 18 cases of proximal humeral fractures in group B included 3 cases of Neer two-part fractures, 9 cases of three-part fractures, and 6 cases of four-part fractures. The true cases of common X-ray and 2D-CT were 7 in Neer three and four-part fractures. 10 cases of proximal humeral fractures in group C included 1 case of Neer two-part fracture, 5 cases of three-part fractures, and 4 cases of four-part fractures. The true cases of 3-D reconstruction, MPR of SCT, and 2D-SCT were 8 in Neer three and four-part fractures. With regard to the true cases of the classification in Neer three and four-part fractures, there was significant difference in three groups and between group A and group C (P<0.05). All SCT and 3-D reconstruction played an important role in the treatment of proximal humeral fractures. Conclusion: Series of good quality X-ray examinations were the first imaging

Operating system design of parallel computer for on-line management of nuclear pressurised water reactor cores

International Nuclear Information System (INIS)

Gougam, F.

1991-04-01

This study is part of the PHAETON project which aims at increasing the knowledge of safety parameters of PWR core and reducing operating margins during the reactor cycle. The on-line system associates a simulator process to compute the three dimensional flux distribution and an acquisition process of reactor core parameters from the central instrumentation. The 3D flux calculation is the most time consuming. So, for cost and safety reasons, the PHAETON project proposes an approach which is to parallelize the 3D diffusion calculation and to use a computer based on parallel processor architecture. This paper presents the design of the operating system on which the application is executed. The routine interface proposed, includes the main operations necessary for programming a real time and parallel application. The primitives include: task management, data transfer, synchronisation by event signalling and by using the rendez-vous mechanisms. The primitives which are proposed use standard softwares like real-time kernel and UNIX operating system [fr

Endovascular aneurysm repair simulation can lead to decreased fluoroscopy time and accurately delineate the proximal seal zone.

Science.gov (United States)

Kim, Ann H; Kendrick, Daniel E; Moorehead, Pamela A; Nagavalli, Anil; Miller, Claire P; Liu, Nathaniel T; Wang, John C; Kashyap, Vikram S

2016-07-01

The use of simulators for endovascular aneurysm repair (EVAR) is not widespread. We examined whether simulation could improve procedural variables, including operative time and optimizing proximal seal. For the latter, we compared suprarenal vs infrarenal fixation endografts, right femoral vs left femoral main body access, and increasing angulation of the proximal aortic neck. Computed tomography angiography was obtained from 18 patients who underwent EVAR at a single institution. Patient cases were uploaded to the ANGIO Mentor endovascular simulator (Simbionix, Cleveland, Ohio) allowing for three-dimensional reconstruction and adapted for simulation with suprarenal fixation (Endurant II; Medtronic Inc, Minneapolis, Minn) and infrarenal fixation (C3; W. L. Gore & Associates Inc, Newark, Del) deployment systems. Three EVAR novices and three experienced surgeons performed 18 cases from each side with each device in randomized order (n = 72 simulations/participant). The cases were stratified into three groups according to the degree of infrarenal angulation: 0° to 20°, 21° to 40°, and 41° to 66°. Statistical analysis used paired t-test and one-way analysis of variance. Mean fluoroscopy time for participants decreased by 48.6% (P time decreased by 33.8% (P zone coverage in highly angulated aortic necks was significantly decreased. The infrarenal device resulted in mean aortic neck zone coverage of 91.9%, 89.4%, and 75.4% (P zone coverage. The side of femoral access for the main body did not influence proximal seal zone coverage regardless of infrarenal angulation. Simulation of EVAR leads to decreased fluoroscopy times for novice and experienced operators. Side of femoral access did not affect precision of proximal endograft landing. The angulated aortic neck leads to decreased proximal seal zone coverage regardless of infrarenal or suprarenal fixation devices. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

PROXIMAL: a method for Prediction of Xenobiotic Metabolism.

Science.gov (United States)

Yousofshahi, Mona; Manteiga, Sara; Wu, Charmian; Lee, Kyongbum; Hassoun, Soha

2015-12-22

Contamination of the environment with bioactive chemicals has emerged as a potential public health risk. These substances that may cause distress or disease in humans can be found in air, water and food supplies. An open question is whether these chemicals transform into potentially more active or toxic derivatives via xenobiotic metabolizing enzymes expressed in the body. We present a new prediction tool, which we call PROXIMAL (Prediction of Xenobiotic Metabolism) for identifying possible transformation products of xenobiotic chemicals in the liver. Using reaction data from DrugBank and KEGG, PROXIMAL builds look-up tables that catalog the sites and types of structural modifications performed by Phase I and Phase II enzymes. Given a compound of interest, PROXIMAL searches for substructures that match the sites cataloged in the look-up tables, applies the corresponding modifications to generate a panel of possible transformation products, and ranks the products based on the activity and abundance of the enzymes involved. PROXIMAL generates transformations that are specific for the chemical of interest by analyzing the chemical's substructures. We evaluate the accuracy of PROXIMAL's predictions through case studies on two environmental chemicals with suspected endocrine disrupting activity, bisphenol A (BPA) and 4-chlorobiphenyl (PCB3). Comparisons with published reports confirm 5 out of 7 and 17 out of 26 of the predicted derivatives for BPA and PCB3, respectively. We also compare biotransformation predictions generated by PROXIMAL with those generated by METEOR and Metaprint2D-react, two other prediction tools. PROXIMAL can predict transformations of chemicals that contain substructures recognizable by human liver enzymes. It also has the ability to rank the predicted metabolites based on the activity and abundance of enzymes involved in xenobiotic transformation.

Integrated Force and Distance Sensing using Elastomer-Embedded Commodity Proximity Sensors.

Energy Technology Data Exchange (ETDEWEB)

Patel, Radhen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cox, Rebecca E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Correll, Nikolaus [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-02-01

We describe a combined proximity, contact and force (PCF) sensor based on a commodity infrared distance sensor embedded in a transparent elastomer with applications in robotic manipulation. Prior to contact, the sensor works as a distance sensor (0{6 cm), whereas after contact the material doubles as a spring, with force proportional to the compression of the elastomer (0{5 N). We describe its principle of operation and design parameters, including polymer thickness, mixing ratio, and emitter current, and show that the sensor response has an in ection point at contact that is independent of an object's surface properties, making it a robust detector for contact events. We then demonstrate how arrays of sensors, custom made for a standard Baxter gripper as well as embedded in the nger of the Kinova hand, can be used to (1) improve gripper alignment during grasping, (2) determine contact points with objects, (3) obtain simple 3D models using both proximity and touch, and (4) register point clouds from touch and RGB-D data.

Review of Proximal Nail Antirotation (PFNA and PFNA-2 – Our Local Experience

Directory of Open Access Journals (Sweden)

WL Loo

2011-07-01

Full Text Available The proximal femoral nail antirotation (PFNA device was recently introduced as an option for intramedullary management of pertrochanteric hip fractures. We report here local results with this relatively new implant. Sixty-two patients with pertrochanteric or subtrochanteric fractures underwent intramedullary fixation with PFNA devices in our centre during the 14 month period from September 2008 to October 2009. Data for this report were retrieved from clinical case records and operative notes. We recorded the age, gender, length of stay and operative time, preoperative ambulatory status and days required to regain mobility. Fractures were classified using the AO classification (A1, A2 and A3. Complications were also identified.There were 15 male and 47 female patients and the mean age was 74.3 years. The mean surgical duration was 76.1min and the average length of hospitalisation was 14.5 days. Five cases were noted to have femoral shaft fracture and no occurrences of screw cutout. We found that 83.9% of the patients were able to regain preoperative mobility status by 6 months following surgery. We conclude that the PFNA is an effective implant for stabilisation of proximal hip fractures and that the local complication rate is similar to reports from other centres.

Evaluation of a radar-based proximity warning system for off-highway dump trucks.

Science.gov (United States)

Ruff, Todd

2006-01-01

A radar-based proximity warning system was evaluated by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health to determine if the system would be effective in detecting objects in the blind spots of an off-highway dump truck. An average of five fatalities occur each year in surface mines as a result of an equipment operator not being aware of a smaller vehicle, person or change in terrain near the equipment. Sensor technology that can detect such obstacles and that also is designed for surface mining applications is rare. Researchers worked closely with the radar system manufacturer to test and modify the system on large, off-highway dump trucks at a surface mine over a period of 2 years. The final system was thoroughly evaluated by recording video images from a camera on the rear of the truck and by recording all alarms from the rear-mounted radar. Data show that the system reliably detected small vehicles, berms, people and other equipment. However, alarms from objects that posed no immediate danger were common, supporting the assertion that sensor-based systems for proximity warning should be used in combination with other devices, such as cameras, that would allow the operator to check the source of any alarm.

The developmental spectrum of proximal radioulnar synostosis

Energy Technology Data Exchange (ETDEWEB)

Elliott, Alison M. [University of Manitoba, Winnipeg Regional Health Association Program of Genetics and Metabolism, Winnipeg, MB (Canada); University of Manitoba, Department of Paediatrics and Child Health, Winnipeg, MB (Canada); University of Manitoba, Department of Biochemistry and Medical Genetics, Winnipeg, MB (Canada); University of Manitoba, WRHA Program of Genetics and Metabolism, Departments of Paediatrics and Child Health, Biochemistry and Medical Genetics, Winnipeg, MB (Canada); Kibria, Lisa [University of Manitoba, Department of School of Medical Rehabilitation, Winnipeg, MB (Canada); Reed, Martin H. [University of Manitoba, Department of Paediatrics and Child Health, Winnipeg, MB (Canada); University of Manitoba, Department of Biochemistry and Medical Genetics, Winnipeg, MB (Canada); University of Manitoba, Department of Diagnostic Imaging, Winnipeg, MB (Canada)

2010-01-15

Proximal radioulnar synostosis is a rare upper limb malformation. The elbow is first identifiable at 35 days (after conception), at which stage the cartilaginous anlagen of the humerus, radius and ulna are continuous. Subsequently, longitudinal segmentation produces separation of the distal radius and ulna. However, temporarily, the proximal ends are united and continue to share a common perichondrium. We investigated the hypothesis that posterior congenital dislocation of the radial head and proximal radioulnar fusion are different clinical manifestations of the same primary developmental abnormality. Records were searched for ''proximal radioulnar fusion/posterior radial head dislocation'' in patients followed at the local Children's Hospital and Rehabilitation Centre for Children. Relevant radiographic, demographic and clinical data were recorded. Ethics approval was obtained through the University Research Ethics Board. In total, 28 patients met the inclusion criteria. The majority of patients (16) had bilateral involvement; eight with posterior dislocation of the radial head only; five had posterior radial head dislocation with radioulnar fusion and two had radioulnar fusion without dislocation. One patient had bilateral proximal radioulnar fusion and posterior dislocation of the left radial head. Nine patients had only left-sided involvement, and three had only right-sided involvement.The degree of proximal fusion varied, with some patients showing 'complete' proximal fusion and others showing fusion that occurred slightly distal to the radial head: 'partially separated.' Associated disorders in our cohort included Poland syndrome (two patients), Cornelia de Lange syndrome, chromosome anomalies (including tetrasomy X) and Cenani Lenz syndactyly. The suggestion of a developmental relationship between posterior dislocation of the radial head and proximal radioulnar fusion is supported by the fact that both anomalies

Automated detection and classification of the proximal humerus fracture by using deep learning algorithm.

Science.gov (United States)

Chung, Seok Won; Han, Seung Seog; Lee, Ji Whan; Oh, Kyung-Soo; Kim, Na Ra; Yoon, Jong Pil; Kim, Joon Yub; Moon, Sung Hoon; Kwon, Jieun; Lee, Hyo-Jin; Noh, Young-Min; Kim, Youngjun

2018-03-26

Background and purpose - We aimed to evaluate the ability of artificial intelligence (a deep learning algorithm) to detect and classify proximal humerus fractures using plain anteroposterior shoulder radiographs. Patients and methods - 1,891 images (1 image per person) of normal shoulders (n = 515) and 4 proximal humerus fracture types (greater tuberosity, 346; surgical neck, 514; 3-part, 269; 4-part, 247) classified by 3 specialists were evaluated. We trained a deep convolutional neural network (CNN) after augmentation of a training dataset. The ability of the CNN, as measured by top-1 accuracy, area under receiver operating characteristics curve (AUC), sensitivity/specificity, and Youden index, in comparison with humans (28 general physicians, 11 general orthopedists, and 19 orthopedists specialized in the shoulder) to detect and classify proximal humerus fractures was evaluated. Results - The CNN showed a high performance of 96% top-1 accuracy, 1.00 AUC, 0.99/0.97 sensitivity/specificity, and 0.97 Youden index for distinguishing normal shoulders from proximal humerus fractures. In addition, the CNN showed promising results with 65-86% top-1 accuracy, 0.90-0.98 AUC, 0.88/0.83-0.97/0.94 sensitivity/specificity, and 0.71-0.90 Youden index for classifying fracture type. When compared with the human groups, the CNN showed superior performance to that of general physicians and orthopedists, similar performance to orthopedists specialized in the shoulder, and the superior performance of the CNN was more marked in complex 3- and 4-part fractures. Interpretation - The use of artificial intelligence can accurately detect and classify proximal humerus fractures on plain shoulder AP radiographs. Further studies are necessary to determine the feasibility of applying artificial intelligence in the clinic and whether its use could improve care and outcomes compared with current orthopedic assessments.

Finger island flaps for treatment of dermato-desmogenic flexion contractures of proximal interphalangeal joints

Directory of Open Access Journals (Sweden)

T. S. Antonova

2016-12-01

Full Text Available Soft tissue defect will form after operative treatment of the dermato-desmogenic flexion contractures of fingers interphalangeal joints of the 2–3 grades after excision of the scar. Using the island flaps (Littler at the central vascular pedicle is one of the classical methods of plastic closure of such defects. Goal. To study the effectiveness of the surgical treatment of dermato-desmogenic flexion contractures of proximal interphalangeal joints of the fingers by using finger island flaps at the central vascular or neuro-vascular pedicle. Materials and methods. 14 operations were carried out on 13 patients for removing dermato-desmogenic flexion contractures of proximal interphalangeal (PIP joints of triphalangeal fingers over a 2-year period (2013–2015. The group included patients with a flexion contracture of the 2–3 grades PIP joints of triphalangeal fingers. Operations were performed on average 5 months after the injury (from 1.5 up to 16 months. Finger island flap in all cases was taken from adjacent finger by using the blood supply of their common finger artery. In all cases the island flap on the central pedicel was used, in 9 cases digital nerve was included in the pedicle (Littler. Closure of donor wound was made with free-skin grafts. Permanent splinting of the hand with extension of the interphalangeal joints and moderate flexion of the metacarpophalangeal joints were performed during 7–8 days after surgery, then exercise therapy was prescribed. Results. The results were estimated 6 and 12 months after surgery. All the results were regarded as excellent. In 5 cases of using the flap on a vascular pedicle flap hypoesthesia was detected, that has not led to dysfunction of the hand. Contracture recurrence during follow-up was not observed. Conclusions. Using the surgery for treatment of dermato-desmogenic flexion contractures of proximal interphalangeal joints of the fingers with the island flaps at the central vascular or neuro

An anatomical study of the proximal aspect of the medial femoral condyle to define the proximal-distal condylar length

Directory of Open Access Journals (Sweden)

Chia-Ming Chang

2017-01-01

Full Text Available Objective: Despite its possible role in knee arthroplasty, the proximal-distal condylar length (PDCL of the femur has never been reported in the literature. We conducted an anatomic study of the proximal aspect of the medial femoral condyle to propose a method for measuring the PDCL. Materials and Methods: Inspection of dried bone specimens was carried out to assure the most proximal condylar margin (MPCM as the eligible starting point to measure the PDCL. Simulation surgery was performed on seven pairs of cadaveric knees to verify the clinical application of measuring the PDCL after locating the MPCM. Interobserver reliability of this procedure was also analyzed. Results: Observation of the bone specimens showed that the MPCM is a concavity formed by the junction of the distal end of the supracondylar ridge and the proximal margin of the medial condyle. This anatomically distinctive structure made the MPCM an unambiguous landmark. The cadaveric simulation surgical dissection demonstrated that the MPCM is easily accessed in a surgical setting, making the measurement of the PDCL plausible. The intraclass correlation coefficient was 0.78, indicating good interobserver reliability for this technique. Conclusion: This study has suggested that the PDCL can be measured based on the MPCM in a surgical setting. PDCL measurement might be useful in joint line position management, selection of femoral component sizes, and other applications related to the proximal-distal dimension of the knee. Further investigation is required.

Evaluation and Management of Proximal Humerus Fractures

Directory of Open Access Journals (Sweden)

Ekaterina Khmelnitskaya

2012-01-01

Full Text Available Proximal humerus fractures are common injuries, especially among older osteoporotic women. Restoration of function requires a thorough understanding of the neurovascular, musculotendinous, and bony anatomy. This paper addresses the relevant anatomy and highlights various management options, including indication for arthroplasty. In the vast majority of cases, proximal humerus fractures may be treated nonoperatively. In the case of displaced fractures, when surgical intervention may be pursued, numerous constructs have been investigated. Of these, the proximal humerus locking plate is the most widely used. Arthroplasty is generally reserved for comminuted 4-part fractures, head-split fractures, or fractures with significant underlying arthritic changes. Reverse total shoulder arthroplasty is reserved for patients with a deficient rotator cuff, or highly comminuted tuberosities.

The Life Saving Effects of Hospital Proximity

DEFF Research Database (Denmark)

Bertoli, Paola; Grembi, Veronica

We assess the lifesaving effect of hospital proximity using data on fatality rates of road-traffic accidents. While most of the literature on this topic is based on changes in distance to the nearest hospital triggered by hospital closures and use OLS estimates, our identification comes from......) increases the fatality rate by 13.84% on the sample average. This is equal to a 0.92 additional death per every 100 accidents. We show that OLS estimates provide a downward biased measure of the real effect of hospital proximity because they do not fully solve spatial sorting problems. Proximity matters...... more when the road safety is low; the emergency service is not properly organized, and the nearest hospital has lower quality standards....

Time and Covariance Threshold Triggered Optimal Uncooperative Rendezvous Using Angles-Only Navigation

Directory of Open Access Journals (Sweden)

Yue You

2017-01-01

Full Text Available A time and covariance threshold triggered optimal maneuver planning method is proposed for orbital rendezvous using angles-only navigation (AON. In the context of Yamanaka-Ankersen orbital relative motion equations, the square root unscented Kalman filter (SRUKF AON algorithm is developed to compute the relative state estimations from a low-volume/mass, power saving, and low-cost optical/infrared camera’s observations. Multi-impulsive Hill guidance law is employed in closed-loop linear covariance analysis model, based on which the quantitative relative position robustness and relative velocity robustness index are defined. By balancing fuel consumption, relative position robustness, and relative velocity robustness, we developed a time and covariance threshold triggered two-level optimal maneuver planning method, showing how these results correlate to past methods and missions and how they could potentially influence future ones. Numerical simulation proved that it is feasible to control the spacecraft with a two-line element- (TLE- level uncertain, 34.6% of range, initial relative state to a 100 m v-bar relative station keeping point, at where the trajectory dispersion reduces to 3.5% of range, under a 30% data gap per revolution on account of the eclipse. Comparing with the traditional time triggered maneuver planning method, the final relative position accuracy is improved by one order and the relative trajectory robustness and collision probability are obviously improved and reduced, respectively.

Assessment of navigation cues with proximal force sensing during endovascular catheterization.

Science.gov (United States)

Rafii-Taril, Hedyeh; Payne, Christopher J; Riga, Celia; Bicknell, Colin; Lee, Su-Lin; Yang, Guang-Zhong

2012-01-01

Despite increased use of robotic catheter navigation systems for endovascular intervention procedures, current master-slave platforms have not yet taken into account dexterous manipulation skill used in traditional catheterization procedures. Information on tool forces applied by operators is often limited. A novel force/torque sensor is developed in this paper to obtain behavioural data across different experience levels and identify underlying factors that affect overall operator performance. The miniature device can be attached to any part of the proximal end of the catheter, together with a position sensor attached to the catheter tip, for relating tool forces to catheter dynamics and overall performance. The results show clear differences in manipulation skills between experience groups, thus providing insights into different patterns and range of forces applied during routine endovascular procedures. They also provide important design specifications for ergonomically optimized catheter manipulation platforms with added haptic feedback while maintaining natural skills of the operators.

Proximal Focal Femoral Deficiency in Ibadan a Developing ...

African Journals Online (AJOL)

The cultural aversion to amputation in our environment makes it difficult to employ that option of treatment. Proximal focal femoral deficiency in Ibadan a developing country's perspective and a review of the literature. Keywords: Proximal focal femoral deficiency , congenital malformations , limb malformations , lower limb ...

[Avulsion of the Proximal Hamstring Insertion. Case Reports].

Science.gov (United States)

Mizera, R; Harcuba, R; Kratochvíl, J

2016-01-01

Proximal hamstring avulsion is an uncommon muscle injury with a lack of consensus on indications and the timing and technique of surgery. Poor clinical symptoms and difficulties in the diagnostic process can lead to a false diagnosis. The authors present three cases of proximal hamstring avulsion, two complete and one partial ruptures of the biceps femoris muscle. MRI and ultrasound scans were used for optimal treatment alignment. Acute surgery reconstruction (hamstring strength. Two interesting systematic reviews published on the treatment of proximal hamstring avulsion are discussed in the final part of the paper. Key words: hamstring, rupture, avulsion.

A dual-mode proximity sensor with integrated capacitive and temperature sensing units

International Nuclear Information System (INIS)

Qiu, Shihua; Huang, Ying; He, Xiaoyue; Sun, Zhiguang; Liu, Ping; Liu, Caixia

2015-01-01

The proximity sensor is one of the most important devices in the field of robot application. It can accurately provide the proximity information to assistant robots to interact with human beings and the external environment safely. In this paper, we have proposed and demonstrated a dual-mode proximity sensor composed of capacitive and resistive sensing units. We defined the capacitive type proximity sensor perceiving the proximity information as C-mode and the resistive type proximity sensor detecting as R-mode. Graphene nanoplatelets (GNPs) were chosen as the R-mode sensing material because of its high performance. The dual-mode proximity sensor presents the following features: (1) the sensing distance of the dual-mode proximity sensor has been enlarged compared with the single capacitive proximity sensor in the same geometrical pattern; (2) experiments have verified that the proposed sensor can sense the proximity information of different materials; (3) the proximity sensing capability of the sensor has been improved by two modes perceive collaboratively, for a plastic block at a temperature of 60 °C: the R-mode will perceive the proximity information when the distance d between the sensor and object is 6.0–17.0 mm and the C-mode will do that when their interval is 0–2.0 mm; additionally two modes will work together when the distance is 2.0–6.0 mm. These features indicate our transducer is very valuable in skin-like sensing applications. (paper)

A Regularized Algorithm for the Proximal Split Feasibility Problem

Directory of Open Access Journals (Sweden)

Zhangsong Yao

2014-01-01

Full Text Available The proximal split feasibility problem has been studied. A regularized method has been presented for solving the proximal split feasibility problem. Strong convergence theorem is given.

Proximity approach to problems in topology and analysis

CERN Document Server

Naimpally, Somashekhar

2009-01-01

Dieses Buch konzentriert das aktuelle Gesamtwissen zum Proximity-Konzept und stellt es dem Leser in gut strukturierter Form dar. Hauptaugenmerk liegt auf den vielfältigen Möglichkeiten, die sich aus dem Proximity-Konzept der räumlichen Nähe und seiner Verallgemeinerung im Nearness-Konzept ergeben.

Development of the safety control framework for shield tunneling in close proximity to the operational subway tunnels: case studies in mainland China.

Science.gov (United States)

Li, Xinggao; Yuan, Dajun

2016-01-01

China's largest cities like Beijing and Shanghai have seen a sharp increase in subway network development as a result of the rapid urbanization in the last decade. The cities are still expanding their subway networks now, and many shield tunnels are being or will be constructed in close proximity to the existing operational subway tunnels. The execution plans for the new nearby shield tunnel construction calls for the development of a safety control framework-a set of control standards and best practices to help organizations manage the risks involved. Typical case studies and relevant key technical parameters are presented with a view to presenting the resulting safety control framework. The framework, created through collaboration among the relevant parties, addresses and manages the risks in a systematic way based on actual conditions of each tunnel crossing construction. The framework consists of six parts: (1) inspecting the operational subway tunnels; (2) deciding allowed movements of the existing tunnels and tracks; (3) simulating effects of the shield tunneling on the existing tunnels; (4) doing preparation work; (5) monitoring design and information management; and (6) measures and activation mechanism of the countermeasures. The six components are explained and demonstrated in detail. In the end, discussions made involve construction and post-construction settlement of the operational tunnel, application of the remedial grouting to rectify excessive settlements of the operational tunnel, and use of the innovative tool of the optical fiber measurement for tunnel movement monitoring. It is concluded that the construction movement of the tunnel can be controlled within 15 mm when the shield machine is <7 m in excavation diameter. The post-construction settlement of the tunnel buried in the very soft ground is much greater than its construction settlement, and last several years until reaching a final stable state. Two cases are outlined to demonstrate the

Visiting Vehicle Ground Trajectory Tool

Science.gov (United States)

Hamm, Dustin

2013-01-01

The International Space Station (ISS) Visiting Vehicle Group needed a targeting tool for vehicles that rendezvous with the ISS. The Visiting Vehicle Ground Trajectory targeting tool provides the ability to perform both realtime and planning operations for the Visiting Vehicle Group. This tool provides a highly reconfigurable base, which allows the Visiting Vehicle Group to perform their work. The application is composed of a telemetry processing function, a relative motion function, a targeting function, a vector view, and 2D/3D world map type graphics. The software tool provides the ability to plan a rendezvous trajectory for vehicles that visit the ISS. It models these relative trajectories using planned and realtime data from the vehicle. The tool monitors ongoing rendezvous trajectory relative motion, and ensures visiting vehicles stay within agreed corridors. The software provides the ability to update or re-plan a rendezvous to support contingency operations. Adding new parameters and incorporating them into the system was previously not available on-the-fly. If an unanticipated capability wasn't discovered until the vehicle was flying, there was no way to update things.

Proximity effects in ferromagnet/superconductor structures

International Nuclear Information System (INIS)

Yu, H.L.; Sun, G.Y.; Yang, L.Y.; Xing, D.Y.

2004-01-01

The Nambu spinor Green's function approach is applied to study proximity effects in ferromagnet/superconductor (FM/SC) structures. They include the induced superconducting order parameter and density of states (DOS) with superconducting feature on the FM side, and spin-dependent DOS within the energy gap on the SC side. The latter indicates an appearance of gapless superconductivity and a coexistence of ferromagnetism and superconductivity in a small regime near the interface. The influence of exchange energy in FM and barrier strength at interface on the proximity effects is discussed

Comparison between Tubularised Incised Plate Urethroplasty and Onlay Island Flap Repair in Mid and Proximal Penile Hypospadias

Energy Technology Data Exchange (ETDEWEB)

Javid, L.; Pansota, M. S.; Ahmad, I.; Tariq, M.; Tabassum, S. A. [Bahawal Victoria Hospital Quaid-e-Azam Medical College, Bahawalpur (Pakistan). Dept. of Urology

2014-04-15

Objectives: To evaluate the surgical outcome of tubularised incised plate urethroplasty and onlay island flap repair for mid and proximal penile hypospadias. Methods: The prospective study was conducted at the Bahawal Victoria Hospital, Bahawalpur from June 2011 to May 2013. A total of 60 patients with mid and proximal penile hypospadias in the age range of 02 to 06 years were included. Patients with hypospadias other than mid and proximal penile, with chordee and history of previous hypospadias repair were excluded. Patients were divided into two equal groups. Urethroplasty was done for group I and flap repair for group II. The follow-up period was 12-24 months. SPSS 16 was used for statistical analysis. Results: The mean duration of surgery was 62+-8.72 minutes for group I and 90+-11.25 minutes for group II (p<0.0001). In group I, only 03 (10.0%) patients had complications, while in group II, 09 (30.0%) patients developed complications (p=0.02). Cosmetic results were also excellent in group I compared to group II. Conclusion: Tubularised incised plate urethroplasty was better and superior than onlay island flap repair in terms of less operative time, complication rate and satisfactory cosmetic results for mid and proximal penile hypospadias. (author)

Comparison between tubularised incised plate urethroplasty and onlay island flap repair in mid and proximal penile hypospadias.

Science.gov (United States)

Javid, Latif; Pansota, Mudassar Saeed; Ahmad, Iftikhar; Tariq, Muhammad; Tabassum, Shafqat Ali

2014-04-01

To evaluate the surgical outcome of tubularised incised plate urethroplasty and onlay island flap repair for mid and proximal penile hypospadias. The prospective study was conducted at the Bahawal Victoria Hospital, Bahawalpur from June 2011 to May 2013. A total of 60 patients with mid and proximal penile hypospadias in the age range of 02 to 06 years were included. Patients with hypospadias other than mid and proximal penile, with chordee and history of previous hypospadias repair were excluded. Patients were divided into two equal groups. Urethroplasty was done for group I and flap repair for group II. The follow-up period was 12-24 months. SPSS 16 was used for statistical analysis. The mean duration of surgery was 62 +/- 8.72 minutes for group I and 90 +/- 11.25 minutes for group II (p < 0.0001). In group I, only 03 (10.0%) patients had complications, while in group II, 09 (30.0%) patients developed complications (p = 0.02). Cosmetic results were also excellent in group I compared to group II. Tubularised incised plate urethroplasty was better and superior than onlay island flap repair in terms of less operative time, complication rate and satisfactory cosmetic results for mid and proximal penile hypospadias.

Comparison between Tubularised Incised Plate Urethroplasty and Onlay Island Flap Repair in Mid and Proximal Penile Hypospadias

International Nuclear Information System (INIS)

Javid, L.; Pansota, M.S.; Ahmad, I.; Tariq, M.; Tabassum, S.A.

2014-01-01

Objectives: To evaluate the surgical outcome of tubularised incised plate urethroplasty and onlay island flap repair for mid and proximal penile hypospadias. Methods: The prospective study was conducted at the Bahawal Victoria Hospital, Bahawalpur from June 2011 to May 2013. A total of 60 patients with mid and proximal penile hypospadias in the age range of 02 to 06 years were included. Patients with hypospadias other than mid and proximal penile, with chordee and history of previous hypospadias repair were excluded. Patients were divided into two equal groups. Urethroplasty was done for group I and flap repair for group II. The follow-up period was 12-24 months. SPSS 16 was used for statistical analysis. Results: The mean duration of surgery was 62+-8.72 minutes for group I and 90+-11.25 minutes for group II (p<0.0001). In group I, only 03 (10.0%) patients had complications, while in group II, 09 (30.0%) patients developed complications (p=0.02). Cosmetic results were also excellent in group I compared to group II. Conclusion: Tubularised incised plate urethroplasty was better and superior than onlay island flap repair in terms of less operative time, complication rate and satisfactory cosmetic results for mid and proximal penile hypospadias. (author)

Radiographic and Computed Tomographic Configuration of Incomplete Proximal Fractures of the Proximal Phalanx in Horses Not Used for Racing.

Science.gov (United States)

Brünisholz, Hervé P; Hagen, Regine; Fürst, Anton E; Kuemmerle, Jan M

2015-10-01

To characterize the configuration of incomplete proximal fractures of the proximal phalanx (P1) in horses not used for racing and compare radiographic with computed tomography (CT) findings. Historical cohort. Twenty-four horses with incomplete fractures of P1. Medical records of horses not used for racing diagnosed with an incomplete proximal fracture of P1 based on clinical and radiographic examination and confirmed by CT between 2008 and 2013 were retrieved. Radiographs and CT studies of these horses were analyzed using a subjective grading system and by measuring variables that characterized fracture configuration. Twenty-four horses were included (20 Warmbloods) with a mean age of 9.5 years and mean body weight of 574 kg. Fourteen forelimbs and 10 hind limbs were affected. Mean duration of lameness was 8.7 weeks. Computed tomography was superior to radiography in both identifying the fracture and determining fracture size and location. On CT, 92% of fractures were located in the mid-sagittal plane. Mean proximodistal length of the fracture was 13 mm. Fractures were frequently not bicortical. Fractures in forelimbs were located significantly more dorsally than fractures in hind limbs. A distinct fracture pattern with 2 subchondral lines running parallel in close proximity to each other was identified in 54% of cases. Incomplete proximal fractures of P1 have significant variation in their configurations, especially their dorsopalmar/-plantar location. Computed tomography examination allowed clear identification of the fracture configurations and was superior to radiography. © Copyright 2015 by The American College of Veterinary Surgeons.

Cassini at Saturn Proximal Orbits - Attitude Control Challenges

Science.gov (United States)

Burk, Thomas A.

2013-01-01

The Cassini mission at Saturn will come to an end in the spring and summer of 2017 with a series of 22 orbits that will dip inside the rings of Saturn. These are called proximal orbits and will conclude with spacecraft disposal into the atmosphere of the ringed world on September 15, 2017. These unique orbits that cross the ring plane only a few thousand kilometers above the cloud tops of the planet present new attitude control challenges for the Cassini operations team. Crossing the ring plane so close to the inner edge of the rings means that the Cassini orientation during the crossing will be tailored to protect the sensitive electronics bus of the spacecraft. This orientation will put the sun sensors at some extra risk so this paper discusses how the team prepares for dust hazards. Periapsis is so close to the planet that spacecraft controllability with RCS thrusters needs to be evaluated because of the predicted atmospheric torque near closest approach to Saturn. Radiation during the ring plane crossings will likely trigger single event transients in some attitude control sensors. This paper discusses how the attitude control team deals with radiation hazards. The angular size and unique geometry of the rings and Saturn near periapsis means that star identification will be interrupted and this paper discusses how the safe mode attitude is selected to best deal with these large bright bodies during the proximal orbits.

A pilot project combining multispectral proximal sensors and digital cameras for monitoring tropical pastures

Science.gov (United States)

Handcock, Rebecca N.; Gobbett, D. L.; González, Luciano A.; Bishop-Hurley, Greg J.; McGavin, Sharon L.

2016-08-01

Timely and accurate monitoring of pasture biomass and ground cover is necessary in livestock production systems to ensure productive and sustainable management. Interest in the use of proximal sensors for monitoring pasture status in grazing systems has increased, since data can be returned in near real time. Proximal sensors have the potential for deployment on large properties where remote sensing may not be suitable due to issues such as spatial scale or cloud cover. There are unresolved challenges in gathering reliable sensor data and in calibrating raw sensor data to values such as pasture biomass or vegetation ground cover, which allow meaningful interpretation of sensor data by livestock producers. Our goal was to assess whether a combination of proximal sensors could be reliably deployed to monitor tropical pasture status in an operational beef production system, as a precursor to designing a full sensor deployment. We use this pilot project to (1) illustrate practical issues around sensor deployment, (2) develop the methods necessary for the quality control of the sensor data, and (3) assess the strength of the relationships between vegetation indices derived from the proximal sensors and field observations across the wet and dry seasons. Proximal sensors were deployed at two sites in a tropical pasture on a beef production property near Townsville, Australia. Each site was monitored by a Skye SKR-four-band multispectral sensor (every 1 min), a digital camera (every 30 min), and a soil moisture sensor (every 1 min), each of which were operated over 18 months. Raw data from each sensor was processed to calculate multispectral vegetation indices. The data capture from the digital cameras was more reliable than the multispectral sensors, which had up to 67 % of data discarded after data cleaning and quality control for technical issues related to the sensor design, as well as environmental issues such as water incursion and insect infestations. We recommend

The influence of tourniquet use and operative time on the incidence of deep vein thrombosis in total knee arthroplasty.

Science.gov (United States)

Hernandez, Arnaldo José; Almeida, Adriano Marques de; Fávaro, Edmar; Sguizzato, Guilherme Turola

2012-09-01

To evaluate the association between tourniquet and total operative time during total knee arthroplasty and the occurrence of deep vein thrombosis. Seventy-eight consecutive patients from our institution underwent cemented total knee arthroplasty for degenerative knee disorders. The pneumatic tourniquet time and total operative time were recorded in minutes. Four categories were established for total tourniquet time: 120 minutes. Three categories were defined for operative time: 150 minutes. Between 7 and 12 days after surgery, the patients underwent ascending venography to evaluate the presence of distal or proximal deep vein thrombosis. We evaluated the association between the tourniquet time and total operative time and the occurrence of deep vein thrombosis after total knee arthroplasty. In total, 33 cases (42.3%) were positive for deep vein thrombosis; 13 (16.7%) cases involved the proximal type. We found no statistically significant difference in tourniquet time or operative time between patients with or without deep vein thrombosis. We did observe a higher frequency of proximal deep vein thrombosis in patients who underwent surgery lasting longer than 120 minutes. The mean total operative time was also higher in patients with proximal deep vein thrombosis. The tourniquet time did not significantly differ in these patients. We concluded that surgery lasting longer than 120 minutes increases the risk of proximal deep vein thrombosis.

[The randomized controlled trial of influences of T shape approach on the function of knee joint in the treatment of proximal tibial fractures].

Science.gov (United States)

Peng, Wei-xiong; Zhang, Zhi; Liang, Jie-hong

2008-04-01

To investigate the clinical value of T shape approach in the treatment of proximal tibial fractures. One handrend and thirteen patients of proximal tibial fractures were randomly divided into two groups. Group A: 62 cases underwent the traditional exposure approach. According to Schatzker classification,the cases of II to VI type was 25, 10, 16, 6, 5 respectively. Group B:51 cases underwent T shape approach ahead of knee joint, the cases of II to VI type was 21, 8, 13, 5, 4 respectively. All data were analyzed by SPSS 10.0 to compare operation time, blood loss, duration of hospitalization, healing time, the time of osseous union and complications after operation. Sixty patients in group A and 50 patients in group B were followed-up from 12 to 24 months. (1) Operation time:group B was longer than A (P time:group B was shorter. (4) Mean time of osseous union: 48 group B was shorter. Function of knee: group B was better than group A. (Complication: group B was less than group A. As compared with traditional exposure approach, T shape approach of knee joint had advantages of small scar, fewer complications, faster union of fracture and earlier recovery of joint function. The approach is valuable for the treatment of proximal tibial fractures.

Electromagnetic properties of proximity systems

Science.gov (United States)

Kresin, Vladimir Z.

1985-07-01

Magnetic screening in the proximity system Sα-Mβ, where Mβ is a normal metal N, semiconductor (semimetal), or a superconductor, is studied. Main attention is paid to the low-temperature region where nonlocality plays an important role. The thermodynamic Green's-function method is employed in order to describe the behavior of the proximity system in an external field. The temperature and thickness dependences of the penetration depth λ are obtained. The dependence λ(T) differs in a striking way from the dependence in usual superconductors. The strong-coupling effect is taken into account. A special case of screening in a superconducting film backed by a size-quantizing semimetal film is considered. The results obtained are in good agreement with experimental data.

Electromagnetic properties of proximity systems

International Nuclear Information System (INIS)

Kresin, V.Z.

1985-01-01

Magnetic screening in the proximity system S/sub α/-M/sub β/, where M/sub β/ is a normal metal N, semiconductor (semimetal), or a superconductor, is studied. Main attention is paid to the low-temperature region where nonlocality plays an important role. The thermodynamic Green's-function method is employed in order to describe the behavior of the proximity system in an external field. The temperature and thickness dependences of the penetration depth lambda are obtained. The dependence lambda(T) differs in a striking way from the dependence in usual superconductors. The strong-coupling effect is taken into account. A special case of screening in a superconducting film backed by a size-quantizing semimetal film is considered. The results obtained are in good agreement with experimental data

Proximate analysis of Lentinus squarrosulus (Mont.) Singer and ...

African Journals Online (AJOL)

Each of the mushroom species was separated into its stipe and pileus and used for proximate analysis. There was a highly significant difference (p<0.01) in the proximate composition of the two species. P. atroumbonata had significantly higher crude protein, crude fibre and moisture content than L. squarrosulus while the ...

Genetics Home Reference: proximal 18q deletion syndrome

Science.gov (United States)

... characteristic features. Most cases of proximal 18q deletion syndrome are the result of a new (de novo) deletion and are not inherited from a ... J, Fox PT, Stratton RF, Perry B, Hale DE. Recurrent interstitial deletions of proximal 18q: a new syndrome involving expressive speech delay. Am J Med Genet ...

Superconducting proximity effect in topological materials

Science.gov (United States)

Reeg, Christopher R.

In recent years, there has been a renewed interest in the proximity effect due to its role in the realization of topological superconductivity. In this dissertation, we discuss several results that have been obtained in the field of proximity-induced superconductivity and relate the results to the search for Majorana fermions. First, we show that repulsive electron-electron interactions can induce a non-Majorana zero-energy bound state at the interface between a conventional superconductor and a normal metal. We show that this state is very sensitive to disorder, owing to its lack of topological protection. Second, we show that Rashba spin-orbit coupling, which is one of the key ingredients in engineering a topological superconductor, induces triplet pairing in the proximity effect. When the spin-orbit coupling is strong (i.e., when the characteristic energy scale for spin-orbit coupling is comparable to the Fermi energy), the induced singlet and triplet pairing amplitudes can be comparable in magnitude. Finally, we discuss how the size of the proximity-induced gap, which appears in a low-dimensional material coupled to a superconductor, evolves as the thickness of the (quasi-)low-dimensional material is increased. We show that the induced gap can be comparable to the bulk energy gap of the underlying superconductor in materials that are much thicker than the Fermi wavelength, even in the presence of an interfacial barrier and strong Fermi surface mismatch. This result has important experimental consequences for topological superconductivity, as a sizable gap is required to isolate and detect the Majorana modes.

Proximal focal femoral deficiency: A case report

Directory of Open Access Journals (Sweden)

Shashank Sharma

2015-01-01

Full Text Available Proximal focal femoral deficiency (PFFD is a rare congenital anomaly resulting in limb shortening and disability in young. The exact cause of the disease is not known and it may present as varying grades of affection involving the proximal femur and the acetabulum. Recognition of this rare abnormality on radiographs can help manage these cases better since early institution of therapy may help in achieving adequate growth of the femur.

Internal fixation of proximal fractures of the 2nd and 4th metacarpal and metatarsal bones using bioabsorbable screws.

Science.gov (United States)

Mageed, M; Steinberg, T; Drumm, N; Stubbs, N; Wegert, J; Koene, M

2018-03-01

Fractures involving the proximal one-third of the splint bone are relatively rare and are challenging to treat. A variety of management techniques have been reported in the literature. The aim of this retrospective case series was to describe the clinical presentation and evaluate the efficacy of bioabsorbable polylactic acid screws in internal fixation of proximal fractures of the 2nd and 4th metacarpal and metatarsal bones in horses. The medical records, diagnostic images and outcome of all horses diagnosed with a proximal fracture of the splint bones and treated with partial resection and internal fixation of the proximal stump using bioabsorbable polylactic acid screws between 2014 and 2015 were reviewed. Eight horses met the inclusion criteria. The results showed that there were no complications encountered during screw placement or postoperatively. Six horses returned to full work 3 months after the operation and two horses remained mildly lame. On follow-up radiographs 12 months postoperatively (n = 2) the screws were not completely absorbed. The screws resulted in a cone-shaped radiolucency, which was progressively replaced from the outer margins by bone sclerosis. The use of bioabsorbable screws for fixation of proximal fractures of the splint bone appears to be a safe and feasible technique and may offer several advantages over the use of traditional metallic implants. © 2018 Australian Veterinary Association.

Proximity effect bilayer nano superconducting quantum interference devices for millikelvin magnetometry

Energy Technology Data Exchange (ETDEWEB)

Blois, A., E-mail: a.blois@ucl.ac.uk; Rozhko, S.; Romans, E. J. [London Centre for Nanotechnology, University College London (UCL), 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Hao, L.; Gallop, J. C. [National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom)

2013-12-21

Superconducting quantum interference devices (SQUIDs) incorporating thin film nanobridges as weak links have sensitivities approaching that required for single spin detection at 4.2 K. However, due to thermal hysteresis they are difficult to operate at much lower temperatures which hinder their application to many quantum measurements. To overcome this, we have developed nanoscale SQUIDs made from titanium-gold proximity bilayers. We show that their electrical properties are consistent with a theoretical model developed for heat flow in bilayers and demonstrate that they enable magnetic measurements to be made on a sample at system temperatures down to 60 mK.

Systemic calciphylaxis presenting as a painful, proximal myopathy.

OpenAIRE

Edelstein, C. L.; Wickham, M. K.; Kirby, P. A.

1992-01-01

A renal transplant patient who presented with a painful, proximal myopathy due to systemic calciphylaxis is described. The myopathy preceded the characteristic skin and soft tissue necrosis. Systemic calciphylaxis should be considered in a dialysis or a renal transplant patient presenting with a painful proximal myopathy even in the absence of necrotic skin lesions.

Anatomy and Biomechanics of the Finger Proximal Interphalangeal Joint.

Science.gov (United States)

Pang, Eric Quan; Yao, Jeffrey

2018-05-01

A complete understanding of the normal anatomy and biomechanics of the proximal interphalangeal joint is critical when treating pathology of the joint as well as in the design of new reconstructive treatments. The osseous anatomy dictates the principles of motion at the proximal interphalangeal joint. Subsequently, the joint is stabilized throughout its motion by the surrounding proximal collateral ligament, accessory collateral ligament, and volar plate. The goal of this article is to review the normal anatomy and biomechanics of the proximal interphalangeal joint and its associated structures, most importantly the proper collateral ligament, accessory collateral ligament, and volar plate. Copyright © 2017 Elsevier Inc. All rights reserved.

Context-Aware Community Construction in Proximity-Based Mobile Networks

Directory of Open Access Journals (Sweden)

Na Yu

2015-01-01

Full Text Available Sensor-equipped mobile devices have allowed users to participate in various social networking services. We focus on proximity-based mobile social networking environments where users can share information obtained from different places via their mobile devices when they are in proximity. Since people are more likely to share information if they can benefit from the sharing or if they think the information is of interest to others, there might exist community structures where users who share information more often are grouped together. Communities in proximity-based mobile networks represent social groups where connections are built when people are in proximity. We consider information influence (i.e., specify who shares information with whom as the connection and the space and time related to the shared information as the contexts. To model the potential information influences, we construct an influence graph by integrating the space and time contexts into the proximity-based contacts of mobile users. Further, we propose a two-phase strategy to detect and track context-aware communities based on the influence graph and show how the context-aware community structure improves the performance of two types of mobile social applications.

Symmetry-based reciprocity: evolutionary constraints on a proximate mechanism.

Science.gov (United States)

Campennì, Marco; Schino, Gabriele

2016-01-01

Background. While the evolution of reciprocal cooperation has attracted an enormous attention, the proximate mechanisms underlying the ability of animals to cooperate reciprocally are comparatively neglected. Symmetry-based reciprocity is a hypothetical proximate mechanism that has been suggested to be widespread among cognitively unsophisticated animals. Methods. We developed two agent-based models of symmetry-based reciprocity (one relying on an arbitrary tag and the other on interindividual proximity) and tested their ability both to reproduce significant emergent features of cooperation in group living animals and to promote the evolution of cooperation. Results. Populations formed by agents adopting symmetry-based reciprocity showed differentiated "social relationships" and a positive correlation between cooperation given and received: two common aspects of animal cooperation. However, when reproduction and selection across multiple generations were added to the models, agents adopting symmetry-based reciprocity were outcompeted by selfish agents that never cooperated. Discussion. In order to evolve, hypothetical proximate mechanisms must be able to stand competition from alternative strategies. While the results of our simulations require confirmation using analytical methods, we provisionally suggest symmetry-based reciprocity is to be abandoned as a possible proximate mechanism underlying the ability of animals to reciprocate cooperative interactions.

Hybrid external fixation of the proximal tibia: strategies to improve frame stability.

Science.gov (United States)

Roberts, Craig S; Dodds, James C; Perry, Kelvin; Beck, Dennis; Seligson, David; Voor, Michael J

2003-07-01

To determine the specific frame construction strategies that can increase the stability of hybrid (ring with tensioned wires proximally connected by bars to half-pins distally) external fixation of proximal tibia fractures. DESIGN Repeated measures biomechanical testing. Laboratory. Composite fiberglass tibias. Using the Heidelberg and Ilizarov systems, external fixators were tested on composite fiberglass tibias with a 1-cm proximal osteotomy (OTA fracture classification 41-A3.3) in seven frame configurations: unilateral frames with 5-mm diameter half-pins and 6-mm diameter half-pins; hybrid (as described above), with and without a 6-mm anterior proximal half-pin; a "box" hybrid (additional ring group distal to the fracture connected by symmetrically spaced bars to the proximal rings) with and without an anterior, proximal half-pin; and a full, four-ring configuration. Each configuration was loaded in four positions (central, medial, posterior, and posteromedial). Displacement at point of loading of proximal fragment. The "box" hybrid was stiffer than the standard hybrid for all loading positions. The addition of an anterior half-pin stiffened the standard hybrid and the "box" hybrid. The most dramatic improvements in the stability of hybrid frames used for proximal tibial fractures result from addition of an anterior, proximal half-pin.

MR imaging of proximal femur: age-related changes

International Nuclear Information System (INIS)

Kim, Ju Heon; Jeon, Woo Jin; Sohn, Cheol Ho; Park, Mi Ok; Lee, Seong Mun; Joo, Yang Gu; Suh, Soo Jhi; Pyun, Young Sik

1995-01-01

The purpose of this study is to illustrate MR patterns of signal intensity of proximal femur in normal subjects according to the age distribution. T1-weighted MR images of the proximal femur in 125 subjects, aged 13 days to 25 years, were retrospectively analyzed. Age distribution was classified to 4 groups; below 4 months, 5 months to 4 years, 5 years to 14 years, and 15 years to 25 years. By the age of 4 months, the non-ossified femoral epiphysis was seen as intermediate-signal-intensity cartilage. At 5 months-4 years, the ossified femoral capital epiphysis was seen within intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow surrounded by a rim of low-signal-intensity cortical bone. At 5-14 years, the ossified femoral capital and greater trochanteric epiphysis were seen within the intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow. At 15-25 years, the proximal metaphyseal marrow showed increased signal intensity. Four patterns of the metaphyseal marrow were recognized by Ricci et al. The frequency of pattern 1 a progressively decreased with age. Pattern 2 and 3 were visible in the 15-25 years age group. An understanding of the spectrum of normal age-related change of the proximal femoral cartilage and marrow patterns serves as the foundation for interpretation of proximal femur pathologies

Management of the proximal tibia fractures by mini external fixation: A case series of 30 cases

Directory of Open Access Journals (Sweden)

Samar K Biswas

2014-01-01

Full Text Available Background: Management of high velocity trauma is a challenging problem because of morbidity of trauma and sometime residual problems of failure of proper healing of fractures with the restriction of movements of knee, shortening, and added risk of compartment syndrome in the proximal tibia fracture. There is always risk of post-operative infection and infected non-union in extensive open surgical procedure and internal fixation. Hence, there is always look out for the middle path procedure for a solution to the above said problems with the added advantage of less hospital stay and early return to work by minimal invasive procedure and stabilization of fracture reduction by multiple K-wire fixation with a frame applied externally. Stabilization of fracture with reduced pain allows early movements of neighbouring joint knee and ankle; hence, reduces the chances of fracture diseases. With this we have been stimulated to take-up the study of managing the proximal tibia fracture by mini external fixator. Aim: The aim of this study was to manage proximal tibia fractures by mini external fixator and evaluate the results and efficacy of this method. Material and Method: A total of 30 patients having proximal tibial fractures admitted at our center between 2008 and 2010 were taken and the procedure carried out was closed manipulative reduction and stabilization with mini external fixator. All acute proximal tibia fractures including tibial plateau fractures above 17 years of age of either sex were included in the study. Fracture more than 3 weeks old were excluded from the study. Result: Out of 30 cases 13 were excellent, 14 cases good, and 3 showed fair. It was found that type 5 and 6 of Schatzker′s classification have lesser outcome type of fractures Conclusion: We have found that management of the proximal tibia fractures by mini external fixation method has a better outcome. Early mobilization of knee in the proximal tibia fractures after

Topology of digital images visual pattern discovery in proximity spaces

CERN Document Server

Peters, James F

2014-01-01

This book carries forward recent work on visual patterns and structures in digital images and introduces a near set-based a topology of digital images. Visual patterns arise naturally in digital images viewed as sets of non-abstract points endowed with some form of proximity (nearness) relation. Proximity relations make it possible to construct uniform topolo- gies on the sets of points that constitute a digital image. In keeping with an interest in gaining an understanding of digital images themselves as a rich source of patterns, this book introduces the basics of digital images from a computer vision perspective. In parallel with a computer vision perspective on digital images, this book also introduces the basics of prox- imity spaces. Not only the traditional view of spatial proximity relations but also the more recent descriptive proximity relations are considered. The beauty of the descriptive proximity approach is that it is possible to discover visual set patterns among sets that are non-overlapping ...

Gunshot Wounds in Military Working Dogs in Operation Enduring Freedom and Operation Iraqi Freedom: 29 cases (2003-2009)

Science.gov (United States)

2013-01-01

oxygenmask held in proximity to the dog’s face or taped to a basket-style muzzle ) during evacuation to the VTF. None of the WIA dogs received IV crystalloid...military working dogs in Operation Enduring Freedom and Operation Iraqi Freedom: 29 cases (2003–2009) Janice L. Baker, DVM; Karyn A. Havas, DVM; Laura A...received on the battlefield, and ultimate outcome of U.S. military working dogs that incurred gunshot wound (GSW) injury in Operation Enduring Freedom

Proximate Analysis of Coal

Science.gov (United States)

Donahue, Craig J.; Rais, Elizabeth A.

2009-01-01

This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

Pneumoperitoneum Caused by Air Leakage Through the Percutaneous Puncture Tract as a Complication of Rendezvous Technique: A Case Report

Directory of Open Access Journals (Sweden)

Chiao-Hsiung Chuang

2008-11-01

Full Text Available The rendezvous technique, combining percutaneous and endoscopic procedures, is a safe and effective method to achieve biliary cannulation if an endoscopic approach fails. The two procedures in this technique can be carried out simultaneously or in stages. A simultaneous approach is reported to be associated with fewer complications, and patients undergoing this approach can recover and be discharged more rapidly. Here, we report a complication of pneumoperitoneum in a patient who underwent percutaneous and endoscopic procedures simultaneously for the removal of a common bile duct stone. It was supposed that prolonged air insufflation during endoscopy forced intestinal air to track into the peritoneal cavity through the bile ducts and the puncture tract. Accordingly, a short wait before removing the percutaneous catheter to deflate the intestinal air will be helpful to avoid such a complication.

The reliability and accuracy of two methods for proximal caries detection and depth on directly visible proximal surfaces: an in vitro study

DEFF Research Database (Denmark)

Ekstrand, K R; Alloza, Alvaro Luna; Promisiero, L

2011-01-01

This study aimed to determine the reliability and accuracy of the ICDAS and radiographs in detecting and estimating the depth of proximal lesions on extracted teeth. The lesions were visible to the naked eye. Three trained examiners scored a total of 132 sound/carious proximal surfaces from 106 p...

The sooner, the better: exercise outcome proximity and intrinsic motivation.

Science.gov (United States)

Evans, M Blair; Cooke, Lisa M; Murray, Robyn A; Wilson, Anne E

2014-11-01

Despite evidence that outcomes are highly valued when they are expected sooner rather than further into the future (Ainslie, 1975), limited research effort has been devoted to understanding the role of exercise outcome proximity. The purpose of this study was to examine how temporal proximity to positive outcomes influences exercisers' intrinsic motivation. We expected that focusing people on temporally proximal exercise outcomes would increase intrinsic motivation, especially among low-frequency exercisers. This online experimental study was completed by 135 community exercisers (Mage  = 31.11, SD = 10.29; 62% female) who reported an average of 4.86 exercise bouts per week (SD = 2.12). Participants were randomly assigned to a condition that primed temporally proximal positive exercise outcomes (i.e. experienced during or directly following an exercise bout) or temporally distal outcomes (i.e. experienced after days, months, or years of regular exercise). Participants then reported perceptions of behavioral regulation in exercise. As expected, the proximal exercise outcome condition elicited increased intrinsic regulation among those participants who exercised less frequently (i.e. 1 SD below the mean). This study reveals the importance of considering proximity as an important dimension of exercise outcomes-particularly when promoting intrinsic motivation among relatively infrequent exercisers. © 2014 The International Association of Applied Psychology.

[Growth behaviour after fractures of the proximal radius: differences to the rest of the skeleton].

Science.gov (United States)

Hell, A K; von Laer, L

2014-12-01

Fractures of the proximal end of the radius in the growth phase have three characteristics: the head of the radius articulates with two joint partners and is therefore indispensable for an undisturbed function of the elbow. The blood supply of the proximal end of the radius is via periosteal vessels in the sense of a terminal circulation which makes it extremely vulnerable. Severe trauma caused either by accidents or treatment, can result in partial or complete necrosis with deformity of the head and neck region of the radius. Radioulnar synostosis and chronic epiphysiolysis are irreversible complications which can occur after excessive physiotherapy. Despite a low potency growth plate, in young patients the proximal end of the radius shows an enormous spontaneous correction of dislocations. Side to side shifts, however, will not be remodeled. Therapy should be as atraumatic as possible. Due to the blood supply situation, with the appropriate indications the spontaneous correction and a brief period of immobilization without physiotherapy should be integrated into the therapy concept. If an operation is necessary, repeated traumatic repositioning maneuvers should be avoided and in case of doubt closed or careful open repositioning can be achieved with intramedullary nailing. In order to take the special characteristics of the proximal radius into consideration, the vulnerability and correction potential must be weighed up against each other. Therapy must be as atraumatic as possible. The spontaneous correction potential should be integrated into the primary therapy without overestimating this potential with respect to the extent and age of the patient.

Correlation between social proximity and mobility similarity.

Science.gov (United States)

Fan, Chao; Liu, Yiding; Huang, Junming; Rong, Zhihai; Zhou, Tao

2017-09-20

Human behaviors exhibit ubiquitous correlations in many aspects, such as individual and collective levels, temporal and spatial dimensions, content, social and geographical layers. With rich Internet data of online behaviors becoming available, it attracts academic interests to explore human mobility similarity from the perspective of social network proximity. Existent analysis shows a strong correlation between online social proximity and offline mobility similarity, namely, mobile records between friends are significantly more similar than between strangers, and those between friends with common neighbors are even more similar. We argue the importance of the number and diversity of common friends, with a counter intuitive finding that the number of common friends has no positive impact on mobility similarity while the diversity plays a key role, disagreeing with previous studies. Our analysis provides a novel view for better understanding the coupling between human online and offline behaviors, and will help model and predict human behaviors based on social proximity.

A proximity algorithm accelerated by Gauss-Seidel iterations for L1/TV denoising models

Science.gov (United States)

Li, Qia; Micchelli, Charles A.; Shen, Lixin; Xu, Yuesheng

2012-09-01

Our goal in this paper is to improve the computational performance of the proximity algorithms for the L1/TV denoising model. This leads us to a new characterization of all solutions to the L1/TV model via fixed-point equations expressed in terms of the proximity operators. Based upon this observation we develop an algorithm for solving the model and establish its convergence. Furthermore, we demonstrate that the proposed algorithm can be accelerated through the use of the componentwise Gauss-Seidel iteration so that the CPU time consumed is significantly reduced. Numerical experiments using the proposed algorithm for impulsive noise removal are included, with a comparison to three recently developed algorithms. The numerical results show that while the proposed algorithm enjoys a high quality of the restored images, as the other three known algorithms do, it performs significantly better in terms of computational efficiency measured in the CPU time consumed.

A proximity algorithm accelerated by Gauss–Seidel iterations for L1/TV denoising models

International Nuclear Information System (INIS)

Li, Qia; Shen, Lixin; Xu, Yuesheng; Micchelli, Charles A

2012-01-01

Our goal in this paper is to improve the computational performance of the proximity algorithms for the L1/TV denoising model. This leads us to a new characterization of all solutions to the L1/TV model via fixed-point equations expressed in terms of the proximity operators. Based upon this observation we develop an algorithm for solving the model and establish its convergence. Furthermore, we demonstrate that the proposed algorithm can be accelerated through the use of the componentwise Gauss–Seidel iteration so that the CPU time consumed is significantly reduced. Numerical experiments using the proposed algorithm for impulsive noise removal are included, with a comparison to three recently developed algorithms. The numerical results show that while the proposed algorithm enjoys a high quality of the restored images, as the other three known algorithms do, it performs significantly better in terms of computational efficiency measured in the CPU time consumed. (paper)

Bone mineral density of lumbar spine and proximal femur in healthy males

International Nuclear Information System (INIS)

Akin, S.; Isikli, S.; Korkusuz, F.; Ungan, M.; Senkoylu, A.

2004-01-01

Relationship between BMD and age at lumbar spine and proximal femur in Turkish males was investigated. Two hundred ninety healthy males (aged 20-59 years) were investigated. BMD of the lumbar spine had its peak at ages 30-39, however, the peak for the proximal femur was between the ages of 20 and 29. There was a significant decrease in BMD at proximal femur after these peak values with increasing age. There was a significant correlation between age and the proximal femoral BMD in males and age has a strong predictive power on proximal femur BMD score. (author)

Proximal soil sensors and data fusion for precision agriculture

NARCIS (Netherlands)

Mahmood, H.S.

2013-01-01

different remote and proximal soil sensors are available today that can scan entire fields and give detailed information on various physical, chemical, mechanical and biological soil properties. The first objective of this thesis was to evaluate different proximal soil sensors available today and to

Magnetometry with Low-Resistance Proximity Josephson Junction

Science.gov (United States)

Jabdaraghi, R. N.; Peltonen, J. T.; Golubev, D. S.; Pekola, J. P.

2018-06-01

We characterize a niobium-based superconducting quantum interference proximity transistor (Nb-SQUIPT) and its key constituent formed by a Nb-Cu-Nb SNS weak link. The Nb-SQUIPT and SNS devices are fabricated simultaneously in two separate lithography and deposition steps, relying on Ar ion cleaning of the Nb contact surfaces. The quality of the Nb-Cu interface is characterized by measuring the temperature-dependent equilibrium critical supercurrent of the SNS junction. In the Nb-SQUIPT device, we observe a maximum flux-to-current transfer function value of about 55 nA/Φ_0 in the sub-gap regime of bias voltages. This results in suppression of power dissipation down to a few fW. Low-bias operation of the device with a relatively low probe junction resistance decreases the dissipation by up to two orders of magnitude compared to a conventional device based on an Al-Cu-Al SNS junction and an Al tunnel probe (Al-SQUIPT).

Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission

Science.gov (United States)

Hinkel, Heather; Strube, Matthew; Zipay, John J.; Cryan, Scott

2016-01-01

This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR&D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR&D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion spacecraft. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build-time instead of at design-time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal non-recurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current

Detection of avian influenza antigens in proximity fiber, droplet, and optical waveguide microfluidics

Science.gov (United States)

Yoon, Jeong-Yeol; Heinze, Brian C.; Gamboa, Jessica; You, David J.

2009-05-01

Virus antigens of avian influenza subtype H3N2 were detected on two different microfluidic platforms: microchannel and droplet. Latex immunoagglutination assays were performed using 920-nm highly carboxylated polystyrene beads that are conjugated with antibody to avian influenza virus. The bead suspension was merged with the solutions of avian influenza virus antigens in a Y-junction of a microchannel made by polydimethylsiloxane soft lithography. The resulting latex immunoagglutinations were measured with two optical fibers in proximity setup to detect 45° forward light scattering. Alternatively, 10 μL droplets of a bead suspension and an antigen solution were merged on a superhydrophobic surface (water contact angle = 155°), whose movement was guided by a metal wire, and 180° back light scattering is measured with a backscattering optical probe. Detection limits were 0.1 pg mL-1 for both microchannel with proximity fibers and droplet microfluidics, thanks to the use of micro-positioning stages to help generate reproducible optical signals. Additionally, optical waveguide was tested by constructing optical waveguide channels (filled with mineral oil) within a microfluidic device to detect the same light scattering. Detection limit was 0.1 ng mL-1 for an optical waveguide device, with a strong potential of improvement in the near future. The use of optical waveguide enabled smaller device setup, easier operation, smaller standard deviations and broader linear range of assay than proximity fiber microchannel and droplet microfluidics. Total assay time was less than 10 min.

[Accuracy of computer aided measurement for detecting dental proximal caries lesions in images of cone-beam computed tomography].

Science.gov (United States)

Zhang, Z L; Li, J P; Li, G; Ma, X C

2017-02-09

Objective: To establish and validate a computer program used to aid the detection of dental proximal caries in the images cone beam computed tomography (CBCT) images. Methods: According to the characteristics of caries lesions in X-ray images, a computer aided detection program for proximal caries was established with Matlab and Visual C++. The whole process for caries lesion detection included image import and preprocessing, measuring average gray value of air area, choosing region of interest and calculating gray value, defining the caries areas. The program was used to examine 90 proximal surfaces from 45 extracted human teeth collected from Peking University School and Hospital of Stomatology. The teeth were then scanned with a CBCT scanner (Promax 3D). The proximal surfaces of the teeth were respectively detected by caries detection program and scored by human observer for the extent of lesions with 6-level-scale. With histologic examination serving as the reference standard, the caries detection program and the human observer performances were assessed with receiver operating characteristic (ROC) curves. Student t -test was used to analyze the areas under the ROC curves (AUC) for the differences between caries detection program and human observer. Spearman correlation coefficient was used to analyze the detection accuracy of caries depth. Results: For the diagnosis of proximal caries in CBCT images, the AUC values of human observers and caries detection program were 0.632 and 0.703, respectively. There was a statistically significant difference between the AUC values ( P= 0.023). The correlation between program performance and gold standard (correlation coefficient r (s)=0.525) was higher than that of observer performance and gold standard ( r (s)=0.457) and there was a statistically significant difference between the correlation coefficients ( P= 0.000). Conclusions: The program that automatically detects dental proximal caries lesions could improve the

Laparoendoscopic Rendezvous for Concomitant Cholecystocholedocholithiasis: A Successful Modality Even in the Most Difficult Presentations Including Pregnancy

Directory of Open Access Journals (Sweden)

Bader Hamza Shirah

2016-01-01

Full Text Available Background. Laparoendoscopic rendezvous (LERV technique is emerging as an attractive treatment option for concomitant cholecystocholedocholithiasis. In this paper, we report our experience in performing the LERV technique in patients with unusual presentations in terms of anatomical difficulty, pregnancy, multiple comorbid diseases, and postlaparotomy. We aim to highlight the effectiveness of the LERV technique in some clinical situations where conventional methods would fail or carry high risks in adequately managing concomitant cholecystocholedocholithiasis. Methods. Four patients diagnosed to have concomitant cholecystocholedocholithiasis with associated difficult presentation or comorbid diseases were treated using the LERV technique. One patient presented with difficult anatomy where ERCP failed at initial attempts. Another patient was pregnant (first trimester. A third patient had complex comorbid diseases (bronchial asthma, hypertension, congestive heart failure, and end-stage renal disease on regular hemodialysis. A fourth patient had previous laparotomy and sigmoidectomy for diverticular disease and had severe hospital phobia. Results. All patients tolerated the LERV technique very well; no intraoperative occurrence was reported. The mean operative time was 86.3±17.2 minutes; mean time of the endoscopic part was 29.4±3.57 minutes. The mean blood loss was 44.3±18.2 mL (range 20–85. Residual stone, postoperative complications, postoperative morbidity, and postoperative mortality were 0 (0%. Postoperative short hospital stay was reported in all patients, average 3 days (range 2–4. Conclusion. LERV procedure is a safe and effective treatment option for the management of concomitant cholecystocholedocholithiasis, even in difficult situations where other methods would fail or carry high risks, or in patients presenting with severe comorbid diseases or pregnancy. This procedure may emerge as an attractive alternative option for high

Computational proximity excursions in the topology of digital images

CERN Document Server

Peters, James F

2016-01-01

This book introduces computational proximity (CP) as an algorithmic approach to finding nonempty sets of points that are either close to each other or far apart. Typically in computational proximity, the book starts with some form of proximity space (topological space equipped with a proximity relation) that has an inherent geometry. In CP, two types of near sets are considered, namely, spatially near sets and descriptivelynear sets. It is shown that connectedness, boundedness, mesh nerves, convexity, shapes and shape theory are principal topics in the study of nearness and separation of physical aswell as abstract sets. CP has a hefty visual content. Applications of CP in computer vision, multimedia, brain activity, biology, social networks, and cosmology are included. The book has been derived from the lectures of the author in a graduate course on the topology of digital images taught over the past several years. Many of the students have provided important insights and valuable suggestions. The topics in ...

E4orf1 Enhances Glucose Uptake Independent of Proximal Insulin Signaling.

Science.gov (United States)

Na, Ha-Na; Hegde, Vijay; Dubuisson, Olga; Dhurandhar, Nikhil V

2016-01-01

Impaired proximal insulin signaling is often present in diabetes. Hence, approaches to enhance glucose disposal independent of proximal insulin signaling are desirable. Evidence indicates that Adenovirus-derived E4orf1 protein may offer such an approach. This study determined if E4orf1 improves insulin sensitivity and downregulates proximal insulin signaling in vivo and enhances cellular glucose uptake independent of proximal insulin signaling in vitro. High fat fed mice were injected with a retrovirus plasmid expressing E4orf1, or a null vector. E4orf1 significantly improved insulin sensitivity in response to a glucose load. Yet, their proximal insulin signaling in fat depots was impaired, as indicated by reduced tyrosine phosphorylation of insulin receptor (IR), and significantly increased abundance of ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1). In 3T3-L1 pre-adipocytes E4orf1 expression impaired proximal insulin signaling. Whereas, treatment with rosiglitazone reduced ENPP1 abundance. Unaffected by IR-KD (insulin receptor knockdown) with siRNA, E4orf1 significantly up-regulated distal insulin signaling pathway and enhanced cellular glucose uptake. In vivo, E4orf1 impairs proximal insulin signaling in fat depots yet improves glycemic control. This is probably explained by the ability of E4orf1 to promote cellular glucose uptake independent of proximal insulin signaling. E4orf1 may provide a therapeutic template to enhance glucose disposal in the presence of impaired proximal insulin signaling.

E4orf1 Enhances Glucose Uptake Independent of Proximal Insulin Signaling.

Directory of Open Access Journals (Sweden)

Ha-Na Na

Full Text Available Impaired proximal insulin signaling is often present in diabetes. Hence, approaches to enhance glucose disposal independent of proximal insulin signaling are desirable. Evidence indicates that Adenovirus-derived E4orf1 protein may offer such an approach. This study determined if E4orf1 improves insulin sensitivity and downregulates proximal insulin signaling in vivo and enhances cellular glucose uptake independent of proximal insulin signaling in vitro. High fat fed mice were injected with a retrovirus plasmid expressing E4orf1, or a null vector. E4orf1 significantly improved insulin sensitivity in response to a glucose load. Yet, their proximal insulin signaling in fat depots was impaired, as indicated by reduced tyrosine phosphorylation of insulin receptor (IR, and significantly increased abundance of ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1. In 3T3-L1 pre-adipocytes E4orf1 expression impaired proximal insulin signaling. Whereas, treatment with rosiglitazone reduced ENPP1 abundance. Unaffected by IR-KD (insulin receptor knockdown with siRNA, E4orf1 significantly up-regulated distal insulin signaling pathway and enhanced cellular glucose uptake. In vivo, E4orf1 impairs proximal insulin signaling in fat depots yet improves glycemic control. This is probably explained by the ability of E4orf1 to promote cellular glucose uptake independent of proximal insulin signaling. E4orf1 may provide a therapeutic template to enhance glucose disposal in the presence of impaired proximal insulin signaling.

E4orf1 Enhances Glucose Uptake Independent of Proximal Insulin Signaling

OpenAIRE

Na, Ha-Na; Hegde, Vijay; Dubuisson, Olga; Dhurandhar, Nikhil V.

2016-01-01

Impaired proximal insulin signaling is often present in diabetes. Hence, approaches to enhance glucose disposal independent of proximal insulin signaling are desirable. Evidence indicates that Adenovirus-derived E4orf1 protein may offer such an approach. This study determined if E4orf1 improves insulin sensitivity and downregulates proximal insulin signaling in vivo and enhances cellular glucose uptake independent of proximal insulin signaling in vitro. High fat fed mice were injected with a ...

The female geriatric proximal humeral fracture: protagonist for straight antegrade nailing?

Science.gov (United States)

Lindtner, Richard A; Kralinger, Franz S; Kapferer, Sebastian; Hengg, Clemens; Wambacher, Markus; Euler, Simon A

2017-10-01

Straight antegrade humeral nailing (SAHN) has become a standard technique for the surgical fixation of proximal humeral fractures, which predominantly affect elderly females. The nail's proximal anchoring point has been demonstrated to be critical to ensure reliable fixation in osteoporotic bone and to prevent iatrogenic damage to the superior rotator cuff bony insertion. Anatomical variations of the proximal humerus, however, may preclude satisfactory anchoring of the nail's proximal end and may bare the risk of rotator cuff violation, even though the nail is inserted as recommended. The aim of this study was to evaluate the anatomical suitability of proximal humeri of geriatric females aged 75 years and older for SAHN. Specifically, we sought to assess the proportion of humeri not anatomically amenable to SAHN for proximal humeral fracture. A total of 303 proximal humeri of 241 females aged 75 years and older (mean age 84.5 ± 5.0 years; range 75-102 years) were analyzed for this study. Multiplanar two-dimensional reformations (true ap, true lateral, and axial) were reconstructed from shoulder computed tomography (CT) data sets. The straight antegrade nail's ideal entry point, "critical point" (CP), and critical distance (CD; distance between ideal entry point and CP) were determined. The rate of proximal humeri not anatomically suitable for SAHN (critical type) was assessed regarding proximal reaming diameters of currently available straight antegrade humeral nails. Overall, 35.6% (108/303) of all proximal humeri were found to be "critical types" (CD straight antegrade nails currently in use. Moreover, 43.2% (131/303) of the humeri were considered "critical types" with regard to the alternatively used larger proximal reaming diameter of 11.5 mm. Mean CD was 9.0 ± 1.7 mm (range 3.5-13.5 mm) and did not correlate with age (r = -0.04, P = 0.54). No significant differences in CD and rate of "critical types" were found between left and right humeri

HEMATOMA OF THE PROXIMAL NAIL FOLD. REPORT OF 41 CASES

Directory of Open Access Journals (Sweden)

Chang Patricia

2011-04-01

Full Text Available Background: The proximal fold is an important part of the nail apparatus it contributes to the formation of the nail plate and through the cuticle acts as an impermeable barrier protecting it from any cause.Objective: To know the proximal nail fold hematoma caused by the use of pulse oximeter.Material and Methods: A descriptive study was conducted in 41 patients with proximal nail hematoma secondary to the use of oximetry in patients hospitalized in the Intermediate and Intensive Care Unit at the Hospital General de Enfermedades from December 1, 2007 to December 31, 2010.Results: We studied 41 patients with proximal nail fold hematoma secondary to the use of oximeter, 30 (73.1% were males and 11 (26.8% females. The numbers of fingers affected by pulse oximeter were in one digit. 30 (73.1% cases, in two digits 6 (14.6%, in three digits 3 (7.3%, in 4 digits 1 (2.4% and in 5 digits 1 (2.4% case. The most affected proximal nail fold was right index: 24 (58.5%, right middle 11 (26.8%, right ring 6 (14.6%, left index 12 (29.2%, and left middle 6 (14.6% cases.Conclusions: Hematomas of the proximal nail fold may be caused by different traumatisms. The use of pulse oximeter is one of them.

Lunar Flight Study Series: Volume 8. Earth-Moon Transit Studies Based on Ephemeris Data and Using Best Available Computer Program. Part 3: Analysis of Some Lunar Landing Site Problems Utilizing Two Fundamental Principles

Science.gov (United States)

Tucker, W. B.; Hooper, H. L.

1963-01-01

This report presents two fundamental properties of lunar trajectories and makes use of these properties to solve various lunar landing site problems. Not only are various problems treated and solved but the properties and methods are established for use in the solution of other problems. This report presents an analysis of lunar landing site problems utilizing the direct mission mode as well as the orbital mission mode. A particular landing site is then specified and different flight profiles are analyzed for getting an exploration vehicle to that landing site. Rendezvous compatible lunar orbits for various stay-times at the landing site are treated. Launch opportunities are discussed for establishing rendezvous compatible lunar orbits without powered plane changes. Then, the minimum required plane changes for rendezvous in the lunar orbit are discussed for launching from earth on any day. On days that afford rendezvous compatible opportunities, there are no powered plane change requirements in the operations from launch at AMR through the rendezvous in lunar orbit, after the stay at the lunar site.

Inter-proximal enamel reduction in contemporary orthodontics.

Science.gov (United States)

Pindoria, J; Fleming, P S; Sharma, P K

2016-12-16

Inter-proximal enamel reduction has gained increasing prominence in recent years being advocated to provide space for orthodontic alignment, to refine contact points and to potentially improve long-term stability. An array of techniques and products are available ranging from hand-held abrasive strips to handpiece mounted burs and discs. The indications for inter-proximal enamel reduction and the importance of formal space analysis, together with the various techniques and armamentarium which may be used to perform it safely in both the labial and buccal segments are outlined.

Treatment of proximal ulna and olecranon fractures by dorsal plating

NARCIS (Netherlands)

Kloen, Peter; Buijze, Geert A.

2009-01-01

OBJECTIVE : Anatomic reconstruction of proximal ulna and olecranon fractures allowing early mobilization and prevention of ulnohumeral arthritis. INDICATIONS : Comminuted olecranon or proximal ulna fractures (including Monteggia fractures), olecranon fractures extending distally from the coronoid

Inexact proximal Newton methods for self-concordant functions

DEFF Research Database (Denmark)

Li, Jinchao; Andersen, Martin Skovgaard; Vandenberghe, Lieven

2016-01-01

with an application to L1-regularized covariance selection, in which prior constraints on the sparsity pattern of the inverse covariance matrix are imposed. In the numerical experiments the proximal Newton steps are computed by an accelerated proximal gradient method, and multifrontal algorithms for positive definite...... matrices with chordal sparsity patterns are used to evaluate gradients and matrix-vector products with the Hessian of the smooth component of the objective....

Proximity effects in topological insulator heterostructures

International Nuclear Information System (INIS)

Li Xiao-Guang; Wu Guang-Fen; Zhang Gu-Feng; Culcer Dimitrie; Zhang Zhen-Yu; Chen Hua

2013-01-01

Topological insulators (TIs) are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to Tl-based heterostructures, in which conventional proximity effects give rise to a series of exotic physical phenomena. This paper reviews our recent studies on the potential existence of topological proximity effects at the interface between a topological insulator and a normal insulator or other topologically trivial systems. Using first-principles approaches, we have realized the tunability of the vertical location of the topological helical state via intriguing dual-proximity effects. To further elucidate the control parameters of this effect, we have used the graphene-based heterostructures as prototypical systems to reveal a more complete phase diagram. On the application side of the topological helical states, we have presented a catalysis example, where the topological helical state plays an essential role in facilitating surface reactions by serving as an effective electron bath. These discoveries lay the foundation for accurate manipulation of the real space properties of the topological helical state in TI-based heterostructures and pave the way for realization of the salient functionality of topological insulators in future device applications. (topical review - low-dimensional nanostructures and devices)

comparative proximate composition and antioxidant vitamins

African Journals Online (AJOL)

DR. AMINU

Keywords: Comparative, proximate composition, antioxidant vitamins, honey. INTRODUCTION ... solution of inverted sugars and complex mixture of other saccharides ... enzymatic browning in apple slices and grape juice. (Khan, 1985).

Mapping subsurface in proximity to newly-developed sinkhole along roadway.

Science.gov (United States)

2013-02-01

MS&T acquired electrical resistivity tomography profiles in immediate proximity to a newly-developed sinkhole in Nixa Missouri : The sinkhole has closed a well-traveled municipal roadway and threatens proximal infrastructure. The intent of this inves...

Effect of tube potential and image receptor on the detection of natural proximal caries in primary teeth.

Science.gov (United States)

Sogur, Elif; Baksı, B Güniz; Orhan, Kaan; Paksoy, S Candan; Dogan, Salih; Erdal, Yılmaz S; Mert, Ali

2011-12-01

The aim of this study was to assess the detection of proximal caries in primary teeth at three different tube potentials using Ektaspeed films, storage phosphor plates (SPPs), and a charge-coupled device (CCD). Fifty-three extracted human primary molars with natural proximal caries were radiographed with three different imaging modalities--Digora Optime SPP system, RVGui CCD system, and Ektaspeed films--at 50-, 65-, and 70-kV tube potentials. Three observers scored the resultant images for the presence or absence of caries. The definitive diagnosis was determined by stereomicroscopic assessment. The diagnostic accuracy for each imaging modality was expressed as the area under the receiver operating characteristic curves (A(z)). Differences among the A(z) values were assessed using two-way ANOVA and t tests. Kappa was used to measure inter- and intra-observer agreement. Higher accuracy was found for SPPs compared to film and CCD images at all tube potentials. Accuracy was significantly different only at 50-kV tube setting in favor of SPPs (p tube potential for the diagnosis of proximal caries since further advantages include the elimination of chemical processing, image enhancement, and a better low-contrast detectability performance.

Coherent Doppler lidar for automated space vehicle, rendezvous, station-keeping and capture

Science.gov (United States)

Dunkin, James A.

1991-01-01

Recent advances in eye-safe, short wavelength solid-state lasers offer real potential for the development of compact, reliable, light-weight, efficient coherent lidar. Laser diode pumping of these devices has been demonstrated, thereby eliminating the need for flash lamp pumping, which has been a major drawback to the use of these lasers in space based applications. Also these lasers now have the frequency stability required to make them useful in coherent lidar, which offers all of the advantages of non-coherent lidar, but with the additional advantage that direct determination of target velocity is possible by measurement of the Doppler shift. By combining the Doppler velocity measurement capability with the inherent high angular resolution and range accuracy of lidar it is possible to construct Doppler images of targets for target motion assessment. A coherent lidar based on a Tm,Ho:YAG 2-micrometer wavelength laser was constructed and successfully field tested on atmospheric targets in 1990. This lidar incorporated an all solid state (laser diode pumped) master oscillator, in conjunction with a flash lamp pumped slave oscillator. Solid-state laser technology is rapidly advancing, and with the advent of high efficiency, high power, semiconductor laser diodes as pump sources, all-solid-state, coherent lidars are a real possibility in the near future. MSFC currently has a feasibility demonstration effort under way which will involve component testing, and preliminary design of an all-solid-state, coherent lidar for automatic rendezvous, and capture. This two year effort, funded by the Director's Discretionary Fund is due for completion in 1992.

Spectral analysis and compositing techniques for the Near Earth Asteroid Rendezvous (NEAR Shoemaker), X-ray and Gamma-Ray Spectrometers (XGRS)

CERN Document Server

McClanahan, T P; Nittler, L R; Boynton, W V; Bruckner, J; Squyres, S W; Evans, L G; Bhangoo, J S; Clark, P E; Floyd, S R; McCartney, E; Mikheeva, I; Starr, R D

2001-01-01

An X-ray and Gamma-Ray Spectrometer (XGRS) is on board the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433 Eros. The Eros asteroid is highly oblate and irregular in shape. As a result, analysis methodologies are in many ways a divergence from comparable techniques. Complex temporal, spatial and instrument performance relationships must be accounted for during the analysis process. Field of view and asteroid surface geometry measurements must be modeled and then combined with real measurements of solar, spectral and instrument calibration information to derive scientific results. NEAR is currently orbiting 433 Eros and is in the initial phases of its primary data integration and mapping phases. Initial results have been obtained and bulk chemistry assessments have been obtained through specialized background assessment and data reduction techniques.

The effect of inferomedial screw on postoperative shoulder function and mechanical alignment in proximal humerus fractures.

Science.gov (United States)

Erdoğan, Murat; Desteli, Engin Eren; İmren, Yunus; Üztürk, Ali; Kılıç, Mesut; Sezgin, Hicabi

2014-10-01

The aim of the study was to evaluate the clinical and radiologic results of locking plate fixation with or without inferomedial screw (IMS) in surgically treated proximal humerus fractures. Thirty-six patients with displaced proximal humerus fractures from two centers were operated using locking plate. All of the fractures were classified according to the Neer classification. In 18 of the cases, an additional IMS running through the medial curvature of the surgical neck was used. There was no significant difference among both groups in terms of height, gender, weight, and mechanism of injury. The fractures were evaluated according to the radiographic and functional findings during follow-up period of 14 months in average (range 8-32 months). At the end of first year, shoulder radiographs were received and shoulder examinations were performed using ASES scores. Humeral head-shaft angles were measured by true AP projections. Head-shaft angle measurements were categorized as varus if 145. Mean time for fracture healing was 18 weeks. Complete union was achieved in 35 patients by the end of 6 months. In one of the 18 displaced proximal humerus fractures of IMS (+) group, the head-shaft angle was measured to be <125, whereas six patients had varus deviation in IMS (-) group at follow-up (p < 0.05). Mean ASES scores of IMS (+) group and IMS (-) group were 58.21 ± 5.82 and 38.61 ± 3.44, respectively (p < 0.001). Use of inferomedial screw running through the medial curvature of surgical neck prevents varus deformity and improves functional outcome after surgical treatment for proximal humerus fractures.

Determining the behavioural dose-response relationship of marine mammals to air gun noise and source proximity.

Science.gov (United States)

Dunlop, Rebecca A; Noad, Michael J; McCauley, Robert D; Scott-Hayward, Lindsay; Kniest, Eric; Slade, Robert; Paton, David; Cato, Douglas H

2017-08-15

The effect of various anthropogenic sources of noise (e.g. sonar, seismic surveys) on the behaviour of marine mammals is sometimes quantified as a dose-response relationship, where the probability of an animal behaviourally 'responding' (e.g. avoiding the source) increases with 'dose' (or received level of noise). To do this, however, requires a definition of a 'significant' response (avoidance), which can be difficult to quantify. There is also the potential that the animal 'avoids' not only the source of noise but also the vessel operating the source, complicating the relationship. The proximity of the source is an important variable to consider in the response, yet difficult to account for given that received level and proximity are highly correlated. This study used the behavioural response of humpback whales to noise from two different air gun arrays (20 and 140 cubic inch air gun array) to determine whether a dose-response relationship existed. To do this, a measure of avoidance of the source was developed, and the magnitude (rather than probability) of this response was tested against dose. The proximity to the source, and the vessel itself, was included within the one-analysis model. Humpback whales were more likely to avoid the air gun arrays (but not the controls) within 3 km of the source at levels over 140 re. 1 µPa 2  s -1 , meaning that both the proximity and the received level were important factors and the relationship between dose (received level) and response is not a simple one. © 2017. Published by The Company of Biologists Ltd.

Comparison of different proximity potentials for asymmetric colliding nuclei

International Nuclear Information System (INIS)

Dutt, Ishwar; Puri, Rajeev K.

2010-01-01

Using the different versions of phenomenological proximity potential as well as other parametrizations within the proximity concept, we perform a detailed comparative study of fusion barriers for asymmetric colliding nuclei with asymmetry parameter as high as 0.23. In all, 12 different proximity potentials are robust against the experimental data of 60 reactions. Our detailed study reveals that the surface energy coefficient as well as radius of the colliding nuclei depend significantly on the asymmetry parameter. All models are able to explain the fusion barrier heights within ±10% on the average. The potentials due to Bass 80, AW 95, and Denisov DP explain nicely the fusion cross sections at above- as well as below-barrier energies.

Fractures of the proximal humerus involving the intertubercular groove

International Nuclear Information System (INIS)

Ahovuo, J.; Paavolainen, P.; Bjoerkenheim, J.M.; Helsinki Univ. Central Hospital

1989-01-01

The purpose of this study was to analyse the involvement of the gliding surface of the biceps tendon in fractures of the proximal humerus. Fifteen patients had a fracture of the proximal humerus verified with antero-posterior and axillary radiographs. Tangential radiographs of the intertubercular groove, obtained from the shoulder joint, showed involvement of the intertubercular groove in 13 patients (87%), which could not be shown with other projections. Groove radiographs revealed in 3 patients a dislocation of the fragments of the greater tuberosity large enough to require surgical treatment, but which had not been found using conventional techniques. Therefore, a groove radiograph should be used to precise fractures of the proximal humerus. (orig.)

Selective proximal vagotomy with and without pyloroplasty

International Nuclear Information System (INIS)

Brodersen, E.

1984-01-01

It was the aim of the study described here to gain information relevant to the well-being of patients subjected to selective proximal vagotomy with or without pyroloplasty as soon as possible after surgery. For this purpose, particular care was taken to ascertain the frequency of recidivation and the post-operative occurrence of disturbances in the emptying of gastric contents. In 35 patients solely undergoing SPV and a further 12 individuals, where both SPV and pyroloplasty had been performed, gastric emptying was monitored using a gamma camera and computer system. All patients were given a standardised test meal consisting of 500 ml ready-made milk labeled with 2 mCi 99mTc-HSA. After the patients had been assigned to different study groups according to the gastric emptying rates established in the individual cases, it became evident that there was a correlation between gastric emptying time (T/2) and the occurrence of post-operative discomfort. In the majority of patients the gastric emptying rate was found to be increased as compared to individuals with a healthy stomach. Among a total of 8 patients showing delayed gastric emptying only one, who solely underwent SPV, reported post-operative discomfort. Markedly increased rates of gastric emptying (T/2 ≤ 5 min) were predominantly determined in patients subjected to SPV in conjunction with pyroloplasty. A dumping syndrome and diarrhea were diagnosed in every third patient. Clinical follow-up studies and questionnaires distributed among the study patients showed relapses to occur with a frequency of 6.7%, the recidivation of ulcera being confined to the group of patients merely undergoing SPV. (TRV) [de

Proximal major limb amputations – a retrospective analysis of 45 oncological cases

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Goertz Ole

2009-02-01

Full Text Available Abstract Background Proximal major limb amputations due to malignant tumors have become rare but are still a valuable treatment option in palliation and in some cases can even cure. The aim of this retrospective study was to analyse outcome in those patients, including the postoperative course, survival, pain, quality of life, and prosthesis usage. Methods Data of 45 consecutive patients was acquired from patient's charts and contact to patients, and general practitioners. Patients with interscapulothoracic amputation (n = 14, shoulder disarticulation (n = 13, hemipelvectomy (n = 3 or hip disarticulation (n = 15 were included. Results The rate of proximal major limb amputations in patients treated for sarcoma was 2.3% (37 out of 1597. Survival for all patients was 42.9% after one year and 12.7% after five years. Survival was significantly better in patients with complete tumor resections. Postoperative chemotherapy and radiation did not prolong survival. Eighteen percent of the patients with malignant disease developed local recurrence. In 44%, postoperative complications were observed. Different modalities of postoperative pain management and the site of the amputation had no significant influence on long-term pain assessment and quality of life. Eighty-seven percent suffered from phantom pain, 15.6% considered their quality of life worse than before the operation. Thirty-two percent of the patients who received a prosthesis used it regularly. Conclusion Proximal major limb amputations severely interfere with patients' body function and are the last, albeit valuable, option within the treatment concept of extremity malignancies or severe infections. Besides short survival, high complication rates, and postoperative pain, patients' quality of life can be improved for the time they have remaining.

Bone mineral density of the proximal femur after hip resurfacing arthroplasty: 1-year follow-up study

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Anttila Esa

2011-05-01

Full Text Available Abstract Background Hip resurfacing arthroplasty (HRA is considered a bone-preserving procedure and may eliminate proximal femoral stress shielding and osteolysis. However, in addition to implant-related stress-shielding factors, various patient-related factors may also have an effect on bone mineral density (BMD of the proximal femur in patients with HRA. Thus, we studied the effects of stem-neck angle, demographic variables, and physical functioning on the BMD of the proximal femur in a one-year follow-up. Methods Thirty three patients (9 females and 24 males with a mean (SD age of 55 (9 years were included in the study. BMD was measured two days and 3, 6, and 12 months postoperatively and 10 regions of interest (ROI were used. Stem-neck angle was analyzed from anteroposterior radiographs. Results Three months postoperatively, BMD decreased in six out of 10 regions of interest (ROI on the side operated on and in one ROI on the control side (p Conclusions After an early drop, the BMD of the upper femur was restored and even exceeded the preoperative level at one year follow-up. From a clinical standpoint, the changes in BMD in these HRA patients could not be explained by stem-neck angle or patient related factors.

Acute proximal junctional failure in patients with preoperative sagittal imbalance.

Science.gov (United States)

Smith, Micah W; Annis, Prokopis; Lawrence, Brandon D; Daubs, Michael D; Brodke, Darrel S

2015-10-01

Proximal junctional failure (PJF) is a recognized complication of spinal deformity surgery. Acute PJF (APJF) has recently been demonstrated to be 5.6% in the adult spinal deformity (ASD) population. The incidence and rate of return to the operating room for APJF have not been specifically investigated in individuals with sagittal imbalance. The purpose of this study was to report the incidence of APJF in patients with preoperative sagittal imbalance and the rate of return to the operating room for APJF. This study is based on a retrospective review of prospectively collected database of ASD patients. One hundred seventy-three consecutive patients were included with preoperative sagittal imbalance according to one of the following common parameters: sagittal vertical axis (SVA) greater than 50 mm, global sagittal alignment greater than 45°, or pelvic incidence minus lumbar lordosis greater than 10°. Outcome measure was presence and/or absence of APJF defined as fracture at the upper instrumented vertebra (UIV) or UIV+1, failure of UIV fixation, 15° or more proximal junctional kyphosis, or need for extension of instrumentation within 6 months of surgery. We performed radiographic measurements on X-rays at preoperative, immediate postoperative, and 6-month follow-up visits. The APJF rate was reported for the entire patient population with preoperative sagittal imbalance. Acute PJF incidence was calculated postoperatively for each of the accepted sagittal balance parameters and/or formulas. Patients with persistent postoperative sagittal imbalance were compared with the sagittally balanced group. We also assessed for threshold values. Acute PJF was observed in 60 of 173 patients (35%) and was least common in fusions with the UIV in the upper thoracic (UT) spine (p=.035). Of those who developed APJF, 21.7% required surgery. Proximal junctional kyphosis 15° or more was the most common form of APJF in fusions to the UT spine but least likely to need revision (p=.014

PROXIMAL JUNCTIONAL KYPHOSIS IN ADULT RECONSTRUCTIVE SPINE SURGERY RESULTS FROM INCOMPLETE RESTORATION OF THE LUMBAR LORDOSIS RELATIVE TO THE MAGNITUDE OF THE THORACIC KYPHOSIS

Science.gov (United States)

Mendoza-Lattes, Sergio; Ries, Zachary; Gao, Yubo; Weinstein, Stuart L

2011-01-01

Background Proximal junctional kyphosis (PJK) is defined as: 1) Proximal junction sagittal Cobb angle >≥10°, and 2) Proximal junction sagittal Cobb angle of at least 10° greater than the pre-operative measurement PJK is a common complication which develops in 39% of adults following surgery for spinal deformity. The pathogenesis, risk factors and prevention of this complication are unclear. Methods Of 54 consecutive adults treated with spinal deformity surgery (age≥59.3±10.1 years), 19 of 54 (35%) developed PJK. The average follow-up was 26.8months (range 12 - 42). Radiographic parameters were measured at the pre-operative, early postoperative (4-6 weeks), and final follow-up visits. Sagittal alignment was measured by the ratio between the C7-plumbline and the sacral-femoral distance. Binary logistic regression model with predictor variables included: Age, BMI, C7-plumbline, and whether lumbar lordosis, thoracic kyphosis and sacral slope were present Results Patients who developed PJK and those without PJK presented with comparable age, BMI, pelvic incidence and sagittal imbalance before surgery. They also presented with comparable sacral slope and lumbar lordosis. The average magnitude of thoracic kyphosis was significantly larger than the lumbar lordosis in the proximal junctional kyphosis group, both at baseline and in the early postoperative period, as represented by [(-lumbar )lordosis - (thoracic kyphosis)]; no- PJK versus PJK; 6.6°±23.2° versus -6.6°±14.2°; p≥0.012. This was not effectively addressed with surgery in the PJK group [(-LL-TK): 6.2°±13.1° vs. -5.2°±9.6°; p≥0.004]. This group also presented with signs of pelvic retroversion with a sacral slope of 29.3°±8.2° pre-operatively that was unchanged after surgery (30.4°±8.5° postoperatively). Logistic regression determined that the magnitude of thoracic kyphosis and sagittal balance (C7-plumbline) was the most important predictor of proximal junctional kyphosis. Conclusions

Exploiting Proximity-Based Mobile Apps for Large-Scale Location Privacy Probing

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Shuang Zhao

2018-01-01

Full Text Available Proximity-based apps have been changing the way people interact with each other in the physical world. To help people extend their social networks, proximity-based nearby-stranger (NS apps that encourage people to make friends with nearby strangers have gained popularity recently. As another typical type of proximity-based apps, some ridesharing (RS apps allowing drivers to search nearby passengers and get their ridesharing requests also become popular due to their contribution to economy and emission reduction. In this paper, we concentrate on the location privacy of proximity-based mobile apps. By analyzing the communication mechanism, we find that many apps of this type are vulnerable to large-scale location spoofing attack (LLSA. We accordingly propose three approaches to performing LLSA. To evaluate the threat of LLSA posed to proximity-based mobile apps, we perform real-world case studies against an NS app named Weibo and an RS app called Didi. The results show that our approaches can effectively and automatically collect a huge volume of users’ locations or travel records, thereby demonstrating the severity of LLSA. We apply the LLSA approaches against nine popular proximity-based apps with millions of installations to evaluate the defense strength. We finally suggest possible countermeasures for the proposed attacks.

Comparative morphometric analysis of the proximal femur of African hominids and felids

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Andrew Gallagher

2015-09-01

Full Text Available Size and shape of the mammalian proximal femur and taxon-specific distinctions in the relative proportions of the proximal articulation, the femoral neck and the proximal femoral diaphysis, are critical determinants in its adaptation to differential biomechanical stresses and observed locomotor habitus in different taxa. The morphometrics of the proximal femur are considered equally critical in the assessment of locomotor habitus of extinct fossil mammals, particularly extinct Miocene anthropoids and Plio-Pleistocene hominins. Analyses of size and shape of k=10 dimensions of the proximal femur were undertaken for a large sample series of two extant mammal families the Felidae and Hominidae using conventional multivariate statistical procedures, commonly used size-correction methods, and post-hoc tests of significance. While significant differences in form do exist, there are equally striking convergences in the functional morphology of extant hominid and felid taxa. Multivariate and bivariate allometric analyses confirm that the proximal femur of these two mammalian families share a common underlying structure manifest in a shared first common principal component. Nevertheless, while considerable convergences in general form of the proximal femur of African hominids and large-bodied felids are apparent, there exist equally discreet distinctions which are consistent with the differential structural demands imposed by their distinct locomotor and behavioural habitus.

Detailed investigations of proximal tubular function in Imerslund-Grasbeck syndrome

DEFF Research Database (Denmark)

Storm, Tina; Zeitz, Christina; Cases, Olivier

2013-01-01

expressed in the small intestine as well as the proximal tubules of the kidney and exhibit an interdependent relationship for post-translational processing and trafficking. In the proximal tubules cubilin is involved in the reabsorption of several filtered plasma proteins including vitamin carriers...

[Comparative study of proximal femoral shortening after the third generation of Gamma nail versus proximal femoral nail anti-rotation in treatment of intertrochanteric fracture].

Science.gov (United States)

Hou, Yu; Yao, Qi; Zhang, Gen'ai; Ding, Lixiang

2018-03-01

To explore the difference of the proximal femoral shortening (PFS) between the third generation of Gamma nail (TGN) and the proximal femoral nail anti-rotation (PFNA) in treating intertrochanteric fracture of femur. The clinical data of 158 patients with intertrochanteric fracture of femur who were treated with TGN internal fixation or PFNA internal fixation between January 2014 and December 2015 were retrospectively analysed. The patients were divided into TGN group (69 cases) and PFNA group (89 cases) according to surgical operation. There was no significant difference in gender, age, bone mineral density, causes of injury, AO/Association for the Study of Internal Fixation (AO/ASIF) classification, accompanied disease, and the time from injury to operation between 2 groups ( P >0.05). The result of fracture reduction was divided into 3 types: positive medial cortex support, neutral position cortex support, and negative medial cortex support according to the method of Chang et al . At 18 months postoperatively, bilateral hip anteroposterior X-ray films were taken to measure horizontal PFS values (marked as X), vertical PFS values (marked as Y), and calculate the total PFS values (marked as Z). The PFS values were divided into 4 grades according to the criteria (≤1.0 mm, 1.0-4.9 mm, 5.0-9.9 mm, and ≥10.0 mm), and the constituent ratio was calculated and compared between 2 groups. The X, Y, and Z values and the collodiaphyseal angles of 2 groups at 18 months postoperatively were compared. The X, Y, and Z values of 2 groups of patients with failed fixation and normal healing within 18 months after operation were recorded and compared. The X, Y, and Z values of 2 groups of the patients with different cortex support types were also compared. There were 34 cases of positive medial cortex support, 30 cases of neutral position cortex support, and 5 cases of negative medial cortex support in TGN group, and there were 45, 33, and 11 cases in PFNA group respectively

A New Path-Constrained Rendezvous Planning Approach for Large-Scale Event-Driven Wireless Sensor Networks

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Ahmadreza Vajdi

2018-05-01

Full Text Available We study the problem of employing a mobile-sink into a large-scale Event-Driven Wireless Sensor Networks (EWSNs for the purpose of data harvesting from sensor-nodes. Generally, this employment improves the main weakness of WSNs that is about energy-consumption in battery-driven sensor-nodes. The main motivation of our work is to address challenges which are related to a network’s topology by adopting a mobile-sink that moves in a predefined trajectory in the environment. Since, in this fashion, it is not possible to gather data from sensor-nodes individually, we adopt the approach of defining some of the sensor-nodes as Rendezvous Points (RPs in the network. We argue that RP-planning in this case is a tradeoff between minimizing the number of RPs while decreasing the number of hops for a sensor-node that needs data transformation to the related RP which leads to minimizing average energy consumption in the network. We address the problem by formulating the challenges and expectations as a Mixed Integer Linear Programming (MILP. Henceforth, by proving the NP-hardness of the problem, we propose three effective and distributed heuristics for RP-planning, identifying sojourn locations, and constructing routing trees. Finally, experimental results prove the effectiveness of our approach.

A New Path-Constrained Rendezvous Planning Approach for Large-Scale Event-Driven Wireless Sensor Networks.

Science.gov (United States)

Vajdi, Ahmadreza; Zhang, Gongxuan; Zhou, Junlong; Wei, Tongquan; Wang, Yongli; Wang, Tianshu

2018-05-04

We study the problem of employing a mobile-sink into a large-scale Event-Driven Wireless Sensor Networks (EWSNs) for the purpose of data harvesting from sensor-nodes. Generally, this employment improves the main weakness of WSNs that is about energy-consumption in battery-driven sensor-nodes. The main motivation of our work is to address challenges which are related to a network’s topology by adopting a mobile-sink that moves in a predefined trajectory in the environment. Since, in this fashion, it is not possible to gather data from sensor-nodes individually, we adopt the approach of defining some of the sensor-nodes as Rendezvous Points (RPs) in the network. We argue that RP-planning in this case is a tradeoff between minimizing the number of RPs while decreasing the number of hops for a sensor-node that needs data transformation to the related RP which leads to minimizing average energy consumption in the network. We address the problem by formulating the challenges and expectations as a Mixed Integer Linear Programming (MILP). Henceforth, by proving the NP-hardness of the problem, we propose three effective and distributed heuristics for RP-planning, identifying sojourn locations, and constructing routing trees. Finally, experimental results prove the effectiveness of our approach.

A New Path-Constrained Rendezvous Planning Approach for Large-Scale Event-Driven Wireless Sensor Networks

Science.gov (United States)

Zhang, Gongxuan; Wang, Yongli; Wang, Tianshu

2018-01-01

We study the problem of employing a mobile-sink into a large-scale Event-Driven Wireless Sensor Networks (EWSNs) for the purpose of data harvesting from sensor-nodes. Generally, this employment improves the main weakness of WSNs that is about energy-consumption in battery-driven sensor-nodes. The main motivation of our work is to address challenges which are related to a network’s topology by adopting a mobile-sink that moves in a predefined trajectory in the environment. Since, in this fashion, it is not possible to gather data from sensor-nodes individually, we adopt the approach of defining some of the sensor-nodes as Rendezvous Points (RPs) in the network. We argue that RP-planning in this case is a tradeoff between minimizing the number of RPs while decreasing the number of hops for a sensor-node that needs data transformation to the related RP which leads to minimizing average energy consumption in the network. We address the problem by formulating the challenges and expectations as a Mixed Integer Linear Programming (MILP). Henceforth, by proving the NP-hardness of the problem, we propose three effective and distributed heuristics for RP-planning, identifying sojourn locations, and constructing routing trees. Finally, experimental results prove the effectiveness of our approach. PMID:29734718

Two Stages repair of proximal hypospadias: Review of 33 cases

African Journals Online (AJOL)

HussamHassan

Background/Purpose: Proximal hypospadias with chordee is the most challenging variant of hypospadias to reconstruct. During the last 10 years, the approach to sever hypospadias has been controversial. Materials & Methods: During the period from June 2002 to December 2009, I performed 33 cases with proximal.

An extended proximal esophageal myotomy is necessary to normalize EGJ distensibility during Heller myotomy for achalasia, but not POEM.

Science.gov (United States)

Teitelbaum, Ezra N; Soper, Nathaniel J; Pandolfino, John E; Kahrilas, Peter J; Boris, Lubomyr; Nicodème, Frédéric; Lin, Zhiyue; Hungness, Eric S

2014-10-01

For laparoscopic Heller myotomy (LHM), the optimal myotomy length proximal to the esophagogastric junction (EGJ) is unknown. In this study, we used a functional lumen imaging probe (FLIP) to measure EGJ distensibility changes resulting from variable proximal myotomy lengths during LHM and peroral esophageal myotomy (POEM). Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by pressure) was measured with FLIP after each operative step. During LHM and POEM, each patient's myotomy was performed in two stages: first, a myotomy ablating only the EGJ complex was created (EGJ-M), extending from 2 cm proximal to the EGJ, to 3 cm distal to it. Next, the myotomy was lengthened 4 cm further cephalad to create an extended proximal myotomy (EP-M). Measurements were performed in 12 patients undergoing LHM and 19 undergoing POEM. LHM resulted in an overall increase in DI (1.6 ± 1 vs. 6.3 ± 3.4 mm(2)/mmHg, p myotomy to an EP-M had no additional effect. POEM resulted in a larger overall increase from baseline than LHM (7.9 ± 3.5 vs. 4.7 ± 3.3 mm(2)/mmHg, p myotomy confined to the EGJ complex was sufficient. In this cohort, POEM resulted in a larger overall increase in EGJ distensibility.

A micropuncture study of proximal tubular transport of lithium during osmotic diuresis

DEFF Research Database (Denmark)

Leyssac, P P; Holstein-Rathlou, N H; Skøtt, P

1990-01-01

Lithium and sodium are normally reabsorbed in parallel with water by the renal proximal tubule whereby their tubular fluid-to-plasma concentration ratios (TF/P) remain close to unity throughout the proximal convoluted segment. During osmotic diuresis, the late proximal (TF/P)Na is known to decrease....... The present experiments were undertaken to study whether the late proximal TF/P for Li decreases like that of Na during osmotic diuresis. Data were obtained in a control period (C) and in two successive periods during mannitol diuresis (P1, P2). Glomerular filtration rate decreased gradually during osmotic...

Inter-organizational proximity in the context of logistics – research challenges

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Patrycja Klimas

2015-03-01

Full Text Available Background: One of major areas of modern research econnected with management issues covers inter-organizational networks (including supply chains and cooperation processes aimed at improvement of the effectiveness of their performance to be found in such networks. The logistics is the main factor responsible for effectiveness of the supply chain.  A possible and a quite new direction of research in the area of the performance of processes of the inter-organizational cooperation is the proximity hypothesis that is considered in five dimensions (geographical, organizational, social, cognitive, and institutional. However, according to many authors, there is a lack of research on supply chains conducted from the logistics point of view. The proximity hypothesis in this area of research can be seen as a kind of novum. Therefore, this paper presents the proximity concept from the perspective of the management science, the overview of prior research covering the inter-organizational proximity with supply chain from the logistics point of view as well as the possible future directions of the empirical efforts. Methods: The aim of this paper is to present previous theoretical and empirical results of research covering inter-organizational proximity in logistics and to show current and up-to-date research challenges in this area. The method of the critical analysis of literature is used to realize the goal constructed this way. Results: Knowledge about the influence of the inter-organizational proximity on the performance of supply chains is rather limited, and the research conducted so far, is rather fragmentary and not free of limitations of the conceptual and methodological nature. Additional rationales for further research in this area include knowledge and cognitive gaps indentified in this paper. According to authors the aim of future empirical research should be as follows: (1 unification and update of used conceptual and methodological approaches

Proximal-type epithelioid sarcoma - Case report Sarcoma epitelióide tipo proximal - Relato de caso

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Luciana Mendes dos Santos

2013-06-01

Full Text Available Epithelioid sarcoma, first described by Enzinger in 1970, is a rare soft-tissue sarcoma typically presenting as a subcutaneous or deep dermal mass in distal portions of the extremities of adolescents and young adults. In 1997, Guillou et al. described a different type of epithelioid sarcoma, called proximal-type epithelioid sarcoma, which is found mostly in the pelvic and perineal regions and genital tracts of young to middle-aged adults. It is characterized by a proliferation of epithelioid-like cells with rhabdoid features and the absence of a granuloma-like pattern. In this paper we present a case of proximal-type epithelioid sarcoma with an aggressive clinical course, including distant metastasis and death nine months after diagnosis.O sarcoma epitelióide, primeiramente descrito por Enzinger, em 1970, é uma neoplasia de partes moles que ocorre principalmente nas extremidades distais de adolescentes e adultos jovens. Em 1997, Guillou e cols. descreveram um tipo diferente de sarcoma epitelióide, que afetava frequentemente a região pélvica, períneo e áreas genitais de pacientes de média idade, com exame histológico caracterizado pela proliferação de células com aspecto epitelióide. Neste trabalho, descreve-se caso de paciente que apresentava há três meses duas lesões na região glútea, cujo exame histológico confirmou diagnóstico de sarcoma epitelioide do tipo proximal, já com presença de metástases pulmonares e cerebrais e que foi a óbito nove meses após o diagnóstico.

The shape of the hominoid proximal femur: a geometric morphometric analysis

Science.gov (United States)

Harmon, Elizabeth H

2007-01-01

As part of the hip joint, the proximal femur is an integral locomotor component. Although a link between locomotion and the morphology of some aspects of the proximal femur has been identified, inclusive shapes of this element have not been compared among behaviourally heterogeneous hominoids. Previous analyses have partitioned complex proximal femoral morphology into discrete features (e.g. head, neck, greater trochanter) to facilitate conventional linear measurements. In this study, three-dimensional geometric morphometrics are used to examine the shape of the proximal femur in hominoids to determine whether femoral shape co-varies with locomotor category. Fourteen landmarks are recorded on adult femora of Homo, Pan, Gorilla, Pongo and Hylobates. Generalized Procrustes analysis (GPA) is used to adjust for position, orientation and scale among landmark configurations. Principal components analysis is used to collapse and compare variation in residuals from GPA, and thin-plate spline analysis is used to visualize shape change among taxa. The results indicate that knucklewalking African apes are similar to one another in femoral shape, whereas the more suspensory Asian apes diverge from the African ape pattern. The shape of the human and orangutan proximal femur converge, a result that is best explained in terms of the distinct requirements for locomotion in each group. These findings suggest that the shape of the proximal femur is brought about primarily by locomotor behaviour. PMID:17310545

Computational fluid dynamics in three dimensional angiography: Preliminary hemodynamic results of various proximal geometry

Energy Technology Data Exchange (ETDEWEB)

Kim, Ha Youn; Park, Sung Tae; Bae, Won Kyoung; Goo, Dong Erk [Dept. of Radiology, Soonchunhyang University Hospital, Seoul (Korea, Republic of)

2014-12-15

We studied the influence of proximal geometry on the results of computational fluid dynamics (CFD). We made five models of different proximal geometry from three dimensional angiography of 63-year-old women with intracranial aneurysm. CFD results were analyzed as peak systolic velocity (PSV) at inlet and outlet as well as flow velocity profile at proximal level of internal carotid artery (ICA) aneurysm. Modified model of cavernous one with proximal tubing showed faster PSV at outlet than that at inlet. The PSV of outlets of other models were slower than that of inlets. The flow velocity profiles at immediate proximal to ICA aneurysm showed similar patterns in all models, suggesting that proximal vessel geometries could affect CFD results.

Proximate analysis of female population of wild feather back fish ...

African Journals Online (AJOL)

User

2011-05-09

May 9, 2011 ... Key words: Body composition, Notopterus notopterus, condition factor, wild fish. INTRODUCTION. Proximate body composition is the analysis of water, fat, protein and ash contents of the fish (Love, 1980). Proximate composition is a good indicator of physiology which is needed for routine analysis of ...

High-throughput determination of RNA structure by proximity ligation.

Science.gov (United States)

Ramani, Vijay; Qiu, Ruolan; Shendure, Jay

2015-09-01

We present an unbiased method to globally resolve RNA structures through pairwise contact measurements between interacting regions. RNA proximity ligation (RPL) uses proximity ligation of native RNA followed by deep sequencing to yield chimeric reads with ligation junctions in the vicinity of structurally proximate bases. We apply RPL in both baker's yeast (Saccharomyces cerevisiae) and human cells and generate contact probability maps for ribosomal and other abundant RNAs, including yeast snoRNAs, the RNA subunit of the signal recognition particle and the yeast U2 spliceosomal RNA homolog. RPL measurements correlate with established secondary structures for these RNA molecules, including stem-loop structures and long-range pseudoknots. We anticipate that RPL will complement the current repertoire of computational and experimental approaches in enabling the high-throughput determination of secondary and tertiary RNA structures.

Proximate, Mineral and Phytochemical Composition of Dioscorea ...

African Journals Online (AJOL)

ADOWIE PERE

Keywords: Dioscorea dumetorum, proximate composition, mineral analysis, phytochemical screening ... were analyzed using atomic absorption ... determined using a Hack Dr/200 Spectrophotometer. ... Lead Acetate. +. +. + .... cosmetics.

Proximate composition and antinutrient content of pumpkin ...

African Journals Online (AJOL)

Proximate composition and antinutrient content of pumpkin ( Cucurbita pepo ) and sorghum ( Sorghum bicolor ) flour blends fermented with Lactobacillus plantarum , Aspergillus niger and Bacillus subtilis.

Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †.

Science.gov (United States)

Murdani, Muhammad Harist; Kwon, Joonho; Choi, Yoon-Ho; Hong, Bonghee

2018-03-24

In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes ( Ad-Hoc ) and neighborhood proximity ( Top-K ). Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space.

Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †