Graph-theoretic analysis of discrete-phase-space states for condition change detection and quantification of information

DOEpatents

Hively, Lee M.

2014-09-16

Data collected from devices and human condition may be used to forewarn of critical events such as machine/structural failure or events from brain/heart wave data stroke. By monitoring the data, and determining what values are indicative of a failure forewarning, one can provide adequate notice of the impending failure in order to take preventive measures. This disclosure teaches a computer-based method to convert dynamical numeric data representing physical objects (unstructured data) into discrete-phase-space states, and hence into a graph (structured data) for extraction of condition change.

Stroboscopic Imaging Interferometer for MEMS Performance Measurement

DTIC Science & Technology

2007-07-15

Optical Iocusing L.aser Fiber Optics I) c 0 Mim er Collimator - C d Microcope lcam. indo Cold Objcclive Splitte FingerCCD "Mount irnro MEMS PicL zStack...Electronics and Photonics Laboratory: Microelectronics, VLSI reliability, failure analysis, solid-state device physics, compound semiconductors

Corrosion processes of physical vapor deposition-coated metallic implants.

PubMed

Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

2009-01-01

Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

Oxygen migration during resistance switching and failure of hafnium oxide memristors

DOE PAGES

Kumar, Suhas; Wang, Ziwen; Huang, Xiaopeng; ...

2017-03-06

While the recent establishment of the role of thermophoresis/diffusion-driven oxygen migration during resistance switching in metal oxide memristors provided critical insights required for memristor modeling, extended investigations of the role of oxygen migration during ageing and failure remain to be detailed. Such detailing will enable failure-tolerant design, which can lead to enhanced performance of memristor-based next-generation storage-class memory. Furthermore, we directly observed lateral oxygen migration using in-situ synchrotron x-ray absorption spectromicroscopy of HfO x memristors during initial resistance switching, wear over millions of switching cycles, and eventual failure, through which we determined potential physical causes of failure. Using this information,more » we reengineered devices to mitigate three failure mechanisms and demonstrated an improvement in endurance of about three orders of magnitude.« less

WE-G-BRC-03: Risk Assessment for Physics Plan Review

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

Parker, S.

2016-06-15

Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, themore » medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic.« less

An efficient scan diagnosis methodology according to scan failure mode for yield enhancement

NASA Astrophysics Data System (ADS)

Kim, Jung-Tae; Seo, Nam-Sik; Oh, Ghil-Geun; Kim, Dae-Gue; Lee, Kyu-Taek; Choi, Chi-Young; Kim, InSoo; Min, Hyoung Bok

2008-12-01

Yield has always been a driving consideration during fabrication of modern semiconductor industry. Statistically, the largest portion of wafer yield loss is defective scan failure. This paper presents efficient failure analysis methods for initial yield ramp up and ongoing product with scan diagnosis. Result of our analysis shows that more than 60% of the scan failure dies fall into the category of shift mode in the very deep submicron (VDSM) devices. However, localization of scan shift mode failure is very difficult in comparison to capture mode failure because it is caused by the malfunction of scan chain. Addressing the biggest challenge, we propose the most suitable analysis method according to scan failure mode (capture / shift) for yield enhancement. In the event of capture failure mode, this paper describes the method that integrates scan diagnosis flow and backside probing technology to obtain more accurate candidates. We also describe several unique techniques, such as bulk back-grinding solution, efficient backside probing and signal analysis method. Lastly, we introduce blocked chain analysis algorithm for efficient analysis of shift failure mode. In this paper, we contribute to enhancement of the yield as a result of the combination of two methods. We confirm the failure candidates with physical failure analysis (PFA) method. The direct feedback of the defective visualization is useful to mass-produce devices in a shorter time. The experimental data on mass products show that our method produces average reduction by 13.7% in defective SCAN & SRAM-BIST failure rates and by 18.2% in wafer yield rates.

Emptiness as Material for Devised Theatre Performance

ERIC Educational Resources Information Center

Ames, Margaret

2018-01-01

The article examines the ways in which failure operated in the devising process with a colleague with learning disabilities. Themes of collaboration, co-creativity and power relations are set within the account of a process between the author and a research participant with learning and physical disabilities. The postdramatic device of failure…

Methods for improved forewarning of condition changes in monitoring physical processes

DOEpatents

Hively, Lee M.

2013-04-09

This invention teaches further improvements in methods for forewarning of critical events via phase-space dissimilarity analysis of data from biomedical equipment, mechanical devices, and other physical processes. One improvement involves objective determination of a forewarning threshold (U.sub.FW), together with a failure-onset threshold (U.sub.FAIL) corresponding to a normalized value of a composite measure (C) of dissimilarity; and providing a visual or audible indication to a human observer of failure forewarning and/or failure onset. Another improvement relates to symbolization of the data according the binary numbers representing the slope between adjacent data points. Another improvement relates to adding measures of dissimilarity based on state-to-state dynamical changes of the system. And still another improvement relates to using a Shannon entropy as the measure of condition change in lieu of a connected or unconnected phase space.

Effect of Joule heating and current crowding on electromigration in mobile technology

NASA Astrophysics Data System (ADS)

Tu, K. N.; Liu, Yingxia; Li, Menglu

2017-03-01

In the present era of big data and internet of things, the use of microelectronic products in all aspects of our life is manifested by the ubiquitous presence of mobile devices as i-phones and wearable i-products. These devices are facing the need for higher power and greater functionality applications such as in i-health, yet they are limited by physical size. At the moment, software (Apps) is much ahead of hardware in mobile technology. To advance hardware, the end of Moore's law in two-dimensional integrated circuits can be extended by three-dimensional integrated circuits (3D ICs). The concept of 3D ICs has been with us for more than ten years. The challenge in 3D IC technology is dense packing by using both vertical and horizontal interconnections. Mass production of 3D IC devices is behind schedule due to cost because of low yield and uncertain reliability. Joule heating is serious in a dense structure because of heat generation and dissipation. A change of reliability paradigm has advanced from failure at a specific circuit component to failure at a system level weak-link. Currently, the electronic industry is introducing 3D IC devices in mainframe computers, where cost is not an issue, for the purpose of collecting field data of failure, especially the effect of Joule heating and current crowding on electromigration. This review will concentrate on the positive feedback between Joule heating and electromigration, resulting in an accelerated system level weak-link failure. A new driving force of electromigration, the electric potential gradient force due to current crowding, will be reviewed critically. The induced failure tends to occur in the low current density region.

Rubber-coated bellows improves vibration damping in vacuum lines

NASA Technical Reports Server (NTRS)

Hegland, D. E.; Smith, R. J.

1966-01-01

Compact-vibration damping systems, consisting of rubber-coated metal bellows with a sliding O-ring connector, are used in vacuum lines. The device presents a metallic surface to the vacuum system and combines flexibility with the necessary stiffness. It protects against physical damage, reduces fatigue failure, and provides easy mating of nonparallel lines.

25+ Years of the Hubble Space Telescope and a Simple Error That Cost Millions

ERIC Educational Resources Information Center

Shakerin, Said

2016-01-01

A simple mistake in properly setting up a measuring device caused millions of dollars to be spent in correcting the initial optical failure of the Hubble Space Telescope (HST). This short article is intended as a lesson for a physics laboratory and discussion of errors in measurement.

Comprehensive analysis of cochlear implant failure: usefulness of clinical symptom-based algorithm combined with in situ integrity testing.

PubMed

Yamazaki, Hiroshi; O'Leary, Stephen; Moran, Michelle; Briggs, Robert

2014-04-01

Accurate diagnosis of cochlear implant failures is important for management; however, appropriate strategies to assess possible device failures are not always clear. The purpose of this study is to understand correlation between causes of device failure and the presenting clinical symptoms as well as results of in situ integrity testing and to propose effective strategies for diagnosis of device failure. Retrospective case review. Cochlear implant center at a tertiary referral hospital. Twenty-seven cases with suspected device failure of Cochlear Nucleus systems (excluding CI512 failures) on the basis of deterioration in auditory perception from January 2000 to September 2012 in the Melbourne cochlear implant clinic. Clinical presentations and types of abnormalities on in situ integrity testing were compared with modes of device failure detected by returned device analysis. Sudden deterioration in auditory perception was always observed in cases with "critical damage": either fracture of the integrated circuit or most or all of the electrode wires. Subacute or gradually progressive deterioration in auditory perception was significantly associated with a more limited number of broken electrode wires. Cochlear implant mediated auditory and nonauditory symptoms were significantly associated with an insulation problem. An algorithm based on the time course of deterioration in auditory perception and cochlear implant-mediated auditory and nonauditory symptoms was developed on the basis of these retrospective analyses, to help predict the mode of device failure. In situ integrity testing, which included close monitoring of device function in routine programming sessions as well as repeating the manufacturer's integrity test battery, was sensitive enough to detect malfunction in all suspected device failures, and each mode of device failure showed a characteristic abnormality on in situ integrity testing. Our clinical manifestation-based algorithm combined with in situ integrity testing may be useful for accurate diagnosis and appropriate management of device failure. Close monitoring of device function in routine programming sessions as well as repeating the manufacturer's integrity test battery is important if the initial in situ integrity testing is inconclusive because objective evidence of failure in the implanted device is essential to recommend explantation/reimplantation.

NREL Wins Prestigious UK "Academy Award" for Engineering | News | NREL

Science.gov Websites

College London (UCL), along with NASA, The European Synchrotron, and the UK National Physical Laboratory impressive company." UCL, NREL, NASA, and their partners were recognized in the category of Safety and Device developed by NREL and NASA to study failure mechanisms in Li-ion batteries and then recorded their

VLSI (Very Large Scale Integrated Circuits) Device Reliability Models.

DTIC Science & Technology

1984-12-01

CIRCUIT COMPLEXITY FAILURE RATES FOR... A- 40 MOS SSI/MSI DEVICES IN FAILURE PER 106 HOURS TABLE 5.1.2.5-19: C1 AND C2 CIRCUIT COMPLEXITY FAILURE RATES FOR...A- 40 MOS SSI/MSI DEVICES IN FAILURE PER 106 HOURS TABLE 5.1.2.5-19: Cl AND C2 CIRCUIT COMPLEXITY FAILURE RATES FOR... A-41 LINEAR DEVICES IN...19 National Semiconductor 20 Nitron 21 Raytheon 22 Sprague 23 Synertek 24 Teledyne Crystalonics 25 TRW Semiconductor 26 Zilog The following companies

[Analysis of telemetry, on-line and non-telemetry data for characterization of the physical activity of patients with heart failure].

PubMed

Melczer, Csaba; Melczer, László; Goják, Ilona; Kónyi, Attila; Szabados, Sándor; Raposa, László Bence; Oláh, András; Ács, Pongrác

2017-09-01

Several studies have demonstrated that the prevalence of heart disease can be accounted for between 0.4 and 2% in developed countries. The present study aimed to use the PA% of the telemetry data to estimate the 6-minute walk test result. A total of seventeen patients with heart disease; 3 females and 14 males; age: 57.35 yrs ± 9.54; body mass 98.71 ± 9.89 kg; average BMI 36.69 ± 3.67 were recruited into the study. Using the two sets of values describing physical performance, linear regression was calculated providing a mathematical equation, thus, the Physical Activity % value is used to estimate the distance traveled over a 6-minute walk test. On further data analysis, we have come to the conclusion that the distance walked during the six-minute-long test may be measured by PA% from the data of CRT device. With our method, based on the values received from the physical activity sensor implanted into the resynchronisation devices, changes in patients' health status could be monitored telemetrically with the assistance from the implanted electronic device. Orv Hetil. 2017; 158(35): 1390-1395.

A Physical Heart Failure Simulation System Utilizing the Total Artificial Heart and Modified Donovan Mock Circulation.

PubMed

Crosby, Jessica R; DeCook, Katrina J; Tran, Phat L; Betterton, Edward; Smith, Richard G; Larson, Douglas F; Khalpey, Zain I; Burkhoff, Daniel; Slepian, Marvin J

2017-07-01

With the growth and diversity of mechanical circulatory support (MCS) systems entering clinical use, a need exists for a robust mock circulation system capable of reliably emulating and reproducing physiologic as well as pathophysiologic states for use in MCS training and inter-device comparison. We report on the development of such a platform utilizing the SynCardia Total Artificial Heart and a modified Donovan Mock Circulation System, capable of being driven at normal and reduced output. With this platform, clinically relevant heart failure hemodynamics could be reliably reproduced as evidenced by elevated left atrial pressure (+112%), reduced aortic flow (-12.6%), blunted Starling-like behavior, and increased afterload sensitivity when compared with normal function. Similarly, pressure-volume relationships demonstrated enhanced sensitivity to afterload and decreased Starling-like behavior in the heart failure model. Lastly, the platform was configured to allow the easy addition of a left ventricular assist device (HeartMate II at 9600 RPM), which upon insertion resulted in improvement of hemodynamics. The present configuration has the potential to serve as a viable system for training and research, aimed at fostering safe and effective MCS device use. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Design of Stretchable Electronics Against Impact.

PubMed

Yuan, J H; Pharr, M; Feng, X; Rogers, John A; Huang, Yonggang

2016-10-01

Stretchable electronics offer soft, biocompatible mechanical properties; these same properties make them susceptible to device failure associated with physical impact. This paper studies designs for stretchable electronics that resist failure from impacts due to incorporation of a viscoelastic encapsulation layer. Results indicate that the impact resistance depends on the thickness and viscoelastic properties of the encapsulation layer, as well as the duration of impact. An analytic model for the critical thickness of the encapsulation layer is established. It is shown that a commercially available, low modulus silicone material offers viscous properties that make it a good candidate as the encapsulation layer for stretchable electronics.

Simulations of the failure scenarios of the crab cavities for the nominal scheme of the LHC

NASA Astrophysics Data System (ADS)

Yee, B.; Calaga, R.; Zimmermann, F.; Lopez, R.

2012-02-01

The Crab Cavity (CC) represents a possible solution to the problem of the reduction in luminosity due to the impact angle of two colliding beams. The CC is a Radio Frequency (RF) superconducting cavity which applies a transversal kick into a bunch of particles producing a rotation in order to have a head-on collision to improve the luminosity. For this reason people at the Beams Department-Accelerators & Beams Physics of CERN (BE-ABP) have studied the implementation of the CC scheme at the LHC. It is essential to study the failure scenarios and the damage that can be produced to the lattice devices. We have performed simulations of these failures for the nominal scheme.

Report of the Odyssey FPGA Independent Assessment Team

NASA Technical Reports Server (NTRS)

Mayer, Donald C.; Katz, Richard B.; Osborn, Jon V.; Soden, Jerry M.; Barto, R.; Day, John H. (Technical Monitor)

2001-01-01

An independent assessment team (IAT) was formed and met on April 2, 2001, at Lockheed Martin in Denver, Colorado, to aid in understanding a technical issue for the Mars Odyssey spacecraft scheduled for launch on April 7, 2001. An RP1280A field-programmable gate array (FPGA) from a lot of parts common to the SIRTF, Odyssey, and Genesis missions had failed on a SIRTF printed circuit board. A second FPGA from an earlier Odyssey circuit board was also known to have failed and was also included in the analysis by the IAT. Observations indicated an abnormally high failure rate for flight RP1280A devices (the first flight lot produced using this flow) at Lockheed Martin and the causes of these failures were not determined. Standard failure analysis techniques were applied to these parts, however, additional diagnostic techniques unique for devices of this class were not used, and the parts were prematurely submitted to a destructive physical analysis, making a determination of the root cause of failure difficult. Any of several potential failure scenarios may have caused these failures, including electrostatic discharge, electrical overstress, manufacturing defects, board design errors, board manufacturing errors, FPGA design errors, or programmer errors. Several of these mechanisms would have relatively benign consequences for disposition of the parts currently installed on boards in the Odyssey spacecraft if established as the root cause of failure. However, other potential failure mechanisms could have more dire consequences. As there is no simple way to determine the likely failure mechanisms with reasonable confidence before Odyssey launch, it is not possible for the IAT to recommend a disposition for the other parts on boards in the Odyssey spacecraft based on sound engineering principles.

Ethical challenges with the left ventricular assist device as a destination therapy

PubMed Central

Rizzieri, Aaron G; Verheijde, Joseph L; Rady, Mohamed Y; McGregor, Joan L

2008-01-01

The left ventricular assist device was originally designed to be surgically implanted as a bridge to transplantation for patients with chronic end-stage heart failure. On the basis of the REMATCH trial, the US Food and Drug Administration and the US Centers for Medicare & Medicaid Services approved permanent implantation of the left ventricular assist device as a destination therapy in Medicare beneficiaries who are not candidates for heart transplantation. The use of the left ventricular assist device as a destination therapy raises certain ethical challenges. Left ventricular assist devices can prolong the survival of average recipients compared with optimal medical management of chronic end-stage heart failure. However, the overall quality of life can be adversely affected in some recipients because of serious infections, neurologic complications, and device malfunction. Left ventricular assist devices alter end-of-life trajectories. The caregivers of recipients may experience significant burden (e.g., poor physical health, depression, anxiety, and posttraumatic stress disorder) from destination therapy with left ventricular assist devices. There are also social and financial ramifications for recipients and their families. We advocate early utilization of a palliative care approach and outline prerequisite conditions so that consenting for the use of a left ventricular assist device as a destination therapy is a well informed process. These conditions include: (1) direct participation of a multidisciplinary care team, including palliative care specialists, (2) a concise plan of care for anticipated device-related complications, (3) careful surveillance and counseling for caregiver burden, (4) advance-care planning for anticipated end-of-life trajectories and timing of device deactivation, and (5) a plan to address the long-term financial burden on patients, families, and caregivers. Short-term mechanical circulatory devices (e.g. percutaneous cardiopulmonary bypass, percutaneous ventricular assist devices, etc.) can be initiated in emergency situations as a bridge to permanent implantation of ventricular assist devices in chronic end-stage heart failure. In the absence of first-person (patient) consent, presumed consent or surrogate consent should be used cautiously for the initiation of short-term mechanical circulatory devices in emergency situations as a bridge to permanent implantation of left ventricular assist devices. Future clinical studies of destination therapy with left ventricular assist devices should include measures of recipients' quality of end-of-life care and caregivers' burden. PMID:18694496

Methods for improved forewarning of critical events across multiple data channels

DOEpatents

Hively, Lee M [Philadelphia, TN

2007-04-24

This disclosed invention concerns improvements in forewarning of critical events via phase-space dissimilarity analysis of data from mechanical devices, electrical devices, biomedical data, and other physical processes. First, a single channel of process-indicative data is selected that can be used in place of multiple data channels without sacrificing consistent forewarning of critical events. Second, the method discards data of inadequate quality via statistical analysis of the raw data, because the analysis of poor quality data always yields inferior results. Third, two separate filtering operations are used in sequence to remove both high-frequency and low-frequency artifacts using a zero-phase quadratic filter. Fourth, the method constructs phase-space dissimilarity measures (PSDM) by combining of multi-channel time-serial data into a multi-channel time-delay phase-space reconstruction. Fifth, the method uses a composite measure of dissimilarity (C.sub.i) to provide a forewarning of failure and an indicator of failure onset.

Nanowire growth process modeling and reliability models for nanodevices

NASA Astrophysics Data System (ADS)

Fathi Aghdam, Faranak

Nowadays, nanotechnology is becoming an inescapable part of everyday life. The big barrier in front of its rapid growth is our incapability of producing nanoscale materials in a reliable and cost-effective way. In fact, the current yield of nano-devices is very low (around 10 %), which makes fabrications of nano-devices very expensive and uncertain. To overcome this challenge, the first and most important step is to investigate how to control nano-structure synthesis variations. The main directions of reliability research in nanotechnology can be classified either from a material perspective or from a device perspective. The first direction focuses on restructuring materials and/or optimizing process conditions at the nano-level (nanomaterials). The other direction is linked to nano-devices and includes the creation of nano-electronic and electro-mechanical systems at nano-level architectures by taking into account the reliability of future products. In this dissertation, we have investigated two topics on both nano-materials and nano-devices. In the first research work, we have studied the optimization of one of the most important nanowire growth processes using statistical methods. Research on nanowire growth with patterned arrays of catalyst has shown that the wire-to-wire spacing is an important factor affecting the quality of resulting nanowires. To improve the process yield and the length uniformity of fabricated nanowires, it is important to reduce the resource competition between nanowires during the growth process. We have proposed a physical-statistical nanowire-interaction model considering the shadowing effect and shared substrate diffusion area to determine the optimal pitch that would ensure the minimum competition between nanowires. A sigmoid function is used in the model, and the least squares estimation method is used to estimate the model parameters. The estimated model is then used to determine the optimal spatial arrangement of catalyst arrays. This work is an early attempt that uses a physical-statistical modeling approach to studying selective nanowire growth for the improvement of process yield. In the second research work, the reliability of nano-dielectrics is investigated. As electronic devices get smaller, reliability issues pose new challenges due to unknown underlying physics of failure (i.e., failure mechanisms and modes). This necessitates new reliability analysis approaches related to nano-scale devices. One of the most important nano-devices is the transistor that is subject to various failure mechanisms. Dielectric breakdown is known to be the most critical one and has become a major barrier for reliable circuit design in nano-scale. Due to the need for aggressive downscaling of transistors, dielectric films are being made extremely thin, and this has led to adopting high permittivity (k) dielectrics as an alternative to widely used SiO2 in recent years. Since most time-dependent dielectric breakdown test data on bilayer stacks show significant deviations from a Weibull trend, we have proposed two new approaches to modeling the time to breakdown of bi-layer high-k dielectrics. In the first approach, we have used a marked space-time self-exciting point process to model the defect generation rate. A simulation algorithm is used to generate defects within the dielectric space, and an optimization algorithm is employed to minimize the Kullback-Leibler divergence between the empirical distribution obtained from the real data and the one based on the simulated data to find the best parameter values and to predict the total time to failure. The novelty of the presented approach lies in using a conditional intensity for trap generation in dielectric that is a function of time, space and size of the previous defects. In addition, in the second approach, a k-out-of-n system framework is proposed to estimate the total failure time after the generation of more than one soft breakdown.

WE-G-BRC-02: Risk Assessment for HDR Brachytherapy

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

Mayadev, J.

2016-06-15

Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, themore » medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic.« less

WE-G-BRC-01: Risk Assessment for Radiosurgery

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

Kim, G.

2016-06-15

Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, themore » medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic.« less

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

NONE

Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, themore » medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic.« less

Cathode Degradation in Thallium Bromide Devices

NASA Astrophysics Data System (ADS)

Datta, Amlan; Motakef, Shariar

2015-06-01

Thallium bromide (TlBr) is a wide bandgap, compound semiconductor with high gamma-ray stopping power and promising physical properties. However, performance degradation and the eventual irreversible failure of TlBr devices can occur rapidly at room temperature, due to “polarization”, caused by the electromigration of Tl+ and Br- ions to the electrical contacts across the device. Using the Accelerated Device Degradation (ADD) experiment, the degradation phenomena in TlBr devices have been visualized and recorded. This paper focuses on “ageing” of the device cathode at various temperatures. ADD is a fast and reliable direct characterization technique that can be used to identify the effects of various growth and post-growth process modifications on device degradation. Using this technique we have identified cathode degradation with the migration of Br- ions and an associated generation and growth of Thallium-rich fractal “ferns” from the cathode. Its effect on the radiation response of the device has also been discussed in this paper. The chemical changes in the cathode were characterized using Energy-dispersive X-ray spectroscopy.

Prognostics of Power Electronics, Methods and Validation Experiments

NASA Technical Reports Server (NTRS)

Kulkarni, Chetan S.; Celaya, Jose R.; Biswas, Gautam; Goebel, Kai

2012-01-01

Abstract Failure of electronic devices is a concern for future electric aircrafts that will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. As a result, investigation of precursors to failure in electronics and prediction of remaining life of electronic components is of key importance. DC-DC power converters are power electronics systems employed typically as sourcing elements for avionics equipment. Current research efforts in prognostics for these power systems focuses on the identification of failure mechanisms and the development of accelerated aging methodologies and systems to accelerate the aging process of test devices, while continuously measuring key electrical and thermal parameters. Preliminary model-based prognostics algorithms have been developed making use of empirical degradation models and physics-inspired degradation model with focus on key components like electrolytic capacitors and power MOSFETs (metal-oxide-semiconductor-field-effect-transistor). This paper presents current results on the development of validation methods for prognostics algorithms of power electrolytic capacitors. Particularly, in the use of accelerated aging systems for algorithm validation. Validation of prognostics algorithms present difficulties in practice due to the lack of run-to-failure experiments in deployed systems. By using accelerated experiments, we circumvent this problem in order to define initial validation activities.

To ventricular assist devices or not: When is implantation of a ventricular assist device appropriate in advanced ambulatory heart failure?

PubMed Central

Cerier, Emily; Lampert, Brent C; Kilic, Arman; McDavid, Asia; Deo, Salil V; Kilic, Ahmet

2016-01-01

Advanced heart failure has been traditionally treated via either heart transplantation, continuous inotropes, consideration for hospice and more recently via left ventricular assist devices (LVAD). Heart transplantation has been limited by organ availability and the futility of other options has thrust LVAD therapy into the mainstream of therapy for end stage heart failure. Improvements in technology and survival combined with improvements in the quality of life have made LVADs a viable option for many patients suffering from heart failure. The question of when to implant these devices in those patients with advanced, yet still ambulatory heart failure remains a controversial topic. We discuss the current state of LVAD therapy and the risk vs benefit of these devices in the treatment of heart failure. PMID:28070237

Oxygen therapy devices and portable ventilators for improved physical activity in daily life in patients with chronic respiratory disease.

PubMed

Furlanetto, Karina Couto; Pitta, Fabio

2017-02-01

Patients with hypoxemia and chronic respiratory failure may need to use oxygen therapy to correct hypoxemia and to use ventilatory support to augment alveolar ventilation, reverse abnormalities in blood gases (in particular hypercapnia) and reduce the work of breathing. Areas covered: This narrative review provides an overview on the use of oxygen therapy devices or portable ventilators for improved physical activity in daily life (PADL) as well as discusses the issue of lower mobility in daily life among stable patients with chronic respiratory disease who present indication for long-term oxygen therapy (LTOT) or home-based noninvasive ventilation (NIV). A literature review of these concepts was performed by using all related search terms. Expert commentary: Technological advances led to the development of light and small oxygen therapy devices and portable ventilators which aim to facilitate patients' mobility and ambulation. However, the day-by-day dependence of a device may reduce mobility and partially impair patients' PADL. Nocturnal NIV implementation in hypercapnic patients seems promising to improve PADL. The magnitude of their equipment-related physical inactivity is underexplored up to this moment and more long-term randomized clinical trials and meta-analysis examining the effects of ambulatory oxygen and NIV on PADL are required.

Emerging New Physics with Major Implications for Energy Technology, Biology, and Medicine

NASA Astrophysics Data System (ADS)

Mallove, Eugene F.

2003-03-01

In the past 15 years, reproducible experiments and prototype technological devices have emerged that may revolutionize much of physics and chemistry(despite the common perception that modern physics is on very solid ground and is nearing a "Theory of Everything"). This new physics has flourished despite very strong opposition by the entrenched foundational paradigms within physics and chemistry ( not to forget vested financial interests within academia). In fact, beginning with "cold fusion" (more generically low-energy nuclear reactions, LENR), one of the most important discoveries of the late 20th Century has been the irrefutable proof of the failure of the physics establishment to deal ethically and appropriately with potential and real paradigm shifts, when its "sacred writ" ( i.e. Its textbooks) -- are threatened with the need for massive revision.

Mechanical Circulatory Support Devices for Acute Right Ventricular Failure.

PubMed

Kapur, Navin K; Esposito, Michele L; Bader, Yousef; Morine, Kevin J; Kiernan, Michael S; Pham, Duc Thinh; Burkhoff, Daniel

2017-07-18

Right ventricular (RV) failure remains a major cause of global morbidity and mortality for patients with advanced heart failure, pulmonary hypertension, or acute myocardial infarction and after major cardiac surgery. Over the past 2 decades, percutaneously delivered acute mechanical circulatory support pumps specifically designed to support RV failure have been introduced into clinical practice. RV acute mechanical circulatory support now represents an important step in the management of RV failure and provides an opportunity to rapidly stabilize patients with cardiogenic shock involving the RV. As experience with RV devices grows, their role as mechanical therapies for RV failure will depend less on the technical ability to place the device and more on improved algorithms for identifying RV failure, patient monitoring, and weaning protocols for both isolated RV failure and biventricular failure. In this review, we discuss the pathophysiology of acute RV failure and both the mechanism of action and clinical data exploring the utility of existing RV acute mechanical circulatory support devices. © 2017 American Heart Association, Inc.

Extracorporeal liver assist device to exchange albumin and remove endotoxin in acute liver failure: Results of a pivotal pre-clinical study.

PubMed

Lee, Karla C L; Baker, Luisa A; Stanzani, Giacomo; Alibhai, Hatim; Chang, Yu Mei; Jimenez Palacios, Carolina; Leckie, Pamela J; Giordano, Paola; Priestnall, Simon L; Antoine, Daniel J; Jenkins, Rosalind E; Goldring, Christopher E; Park, B Kevin; Andreola, Fausto; Agarwal, Banwari; Mookerjee, Rajeshwar P; Davies, Nathan A; Jalan, Rajiv

2015-09-01

In acute liver failure, severity of liver injury and clinical progression of disease are in part consequent upon activation of the innate immune system. Endotoxaemia contributes to innate immune system activation and the detoxifying function of albumin, critical to recovery from liver injury, is irreversibly destroyed in acute liver failure. University College London-Liver Dialysis Device is a novel artificial extracorporeal liver assist device, which is used with albumin infusion, to achieve removal and replacement of dysfunctional albumin and reduction in endotoxaemia. We aimed to test the effect of this device on survival in a pig model of acetaminophen-induced acute liver failure. Pigs were randomised to three groups: Acetaminophen plus University College London-Liver Dialysis Device (n=9); Acetaminophen plus Control Device (n=7); and Control plus Control Device (n=4). Device treatment was initiated two h after onset of irreversible acute liver failure. The Liver Dialysis Device resulted in 67% reduced risk of death in acetaminophen-induced acute liver failure compared to Control Device (hazard ratio=0.33, p=0.0439). This was associated with 27% decrease in circulating irreversibly oxidised human non-mercaptalbumin-2 throughout treatment (p=0.046); 54% reduction in overall severity of endotoxaemia (p=0.024); delay in development of vasoplegia and acute lung injury; and delay in systemic activation of the TLR4 signalling pathway. Liver Dialysis Device-associated adverse clinical effects were not seen. The survival benefit and lack of adverse effects would support clinical trials of University College London-Liver Dialysis Device in acute liver failure patients. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

The future of mechanical circulatory support for advanced heart failure.

PubMed

Marinescu, Karolina K; Uriel, Nir; Adatya, Sirtaz

2016-05-01

Mechanical circulatory support (MCS) has become the main focus of heart replacement therapy for end stage heart failure patients. Advances in technology are moving towards miniaturization, biventricular support devices, complete internalization, improved hemocompatibility profiles, and responsiveness to cardiac loading conditions. This review will discuss the recent advances and investigational devices in MCS for advanced heart failure. The demand for both short-term and long-term durable devices for advanced heart failure is increasing. The current devices are still fraught with an unacceptably high incidence of gastrointestinal bleeding and thromboembolic and infectious complications. New devices are on the horizon focusing on miniaturization, versatility for biventricular support, improved hemocompatibility, use of alternate energy sources, and incorporation of continuous hemodynamic monitoring. The role for MCS in advanced heart replacement therapy is steadily increasing. With the advent of newer generation devices on the horizon, the potential exists for MCS to surpass heart transplantation as the primary therapy for advanced heart failure.

Remote maintenance monitoring system

NASA Technical Reports Server (NTRS)

Simpkins, Lorenz G. (Inventor); Owens, Richard C. (Inventor); Rochette, Donn A. (Inventor)

1992-01-01

A remote maintenance monitoring system retrofits to a given hardware device with a sensor implant which gathers and captures failure data from the hardware device, without interfering with its operation. Failure data is continuously obtained from predetermined critical points within the hardware device, and is analyzed with a diagnostic expert system, which isolates failure origin to a particular component within the hardware device. For example, monitoring of a computer-based device may include monitoring of parity error data therefrom, as well as monitoring power supply fluctuations therein, so that parity error and power supply anomaly data may be used to trace the failure origin to a particular plane or power supply within the computer-based device. A plurality of sensor implants may be rerofit to corresponding plural devices comprising a distributed large-scale system. Transparent interface of the sensors to the devices precludes operative interference with the distributed network. Retrofit capability of the sensors permits monitoring of even older devices having no built-in testing technology. Continuous real time monitoring of a distributed network of such devices, coupled with diagnostic expert system analysis thereof, permits capture and analysis of even intermittent failures, thereby facilitating maintenance of the monitored large-scale system.

Lifetime evaluation of large format CMOS mixed signal infrared devices

NASA Astrophysics Data System (ADS)

Linder, A.; Glines, Eddie

2015-09-01

New large scale foundry processes continue to produce reliable products. These new large scale devices continue to use industry best practice to screen for failure mechanisms and validate their long lifetime. The Failure-in-Time analysis in conjunction with foundry qualification information can be used to evaluate large format device lifetimes. This analysis is a helpful tool when zero failure life tests are typical. The reliability of the device is estimated by applying the failure rate to the use conditions. JEDEC publications continue to be the industry accepted methods.

Integrated otpical monitoring of MEMS for closed-loop control

NASA Astrophysics Data System (ADS)

Dawson, Jeremy M.; Wang, Limin; McCormick, W. B.; Rittenhouse, S. A.; Famouri, Parviz F.; Hornak, Lawrence A.

2003-01-01

Robust control and failure assessment of MEMS employed in physically demanding, mission critical applications will allow for higher degrees of quality assurance in MEMS operation. Device fault detection and closed-loop control require detailed knowledge of the operational states of MEMS over the lifetime of the device, obtained by a means decoupled from the system. Preliminary through-wafer optical monitoring research efforts have shown that through-wafer optical probing is suitable for characterizing and monitoring the behavior of MEMS, and can be implemented in an integrated optical monitoring package for continuous in-situ device monitoring. This presentation will discuss research undertaken to establish integrated optical device metrology for closed-loop control of a MUMPS fabricated lateral harmonic oscillator. Successful linear closed-loop control results using a through-wafer optical microprobe position feedback signal will be presented. A theoretical optical output field intensity study of grating structures, fabricated on the shuttle of the resonator, was performed to improve the position resolution of the optical microprobe position signal. Through-wafer microprobe signals providing a positional resolution of 2 μm using grating structures will be shown, along with initial binary Fresnel diffractive optical microelement design layout, process development, and testing results. Progress in the design, fabrication, and test of integrated optical elements for multiple microprobe signal delivery and recovery will be discussed, as well as simulation of device system model parameter changes for failure assessment.

Stability, Nonlinearity and Reliability of Electrostatically Actuated MEMS Devices

PubMed Central

Zhang, Wen-Ming; Meng, Guang; Chen, Di

2007-01-01

Electrostatic micro-electro-mechanical system (MEMS) is a special branch with a wide range of applications in sensing and actuating devices in MEMS. This paper provides a survey and analysis of the electrostatic force of importance in MEMS, its physical model, scaling effect, stability, nonlinearity and reliability in detail. It is necessary to understand the effects of electrostatic forces in MEMS and then many phenomena of practical importance, such as pull-in instability and the effects of effective stiffness, dielectric charging, stress gradient, temperature on the pull-in voltage, nonlinear dynamic effects and reliability due to electrostatic forces occurred in MEMS can be explained scientifically, and consequently the great potential of MEMS technology could be explored effectively and utilized optimally. A simplified parallel-plate capacitor model is proposed to investigate the resonance response, inherent nonlinearity, stiffness softened effect and coupled nonlinear effect of the typical electrostatically actuated MEMS devices. Many failure modes and mechanisms and various methods and techniques, including materials selection, reasonable design and extending the controllable travel range used to analyze and reduce the failures are discussed in the electrostatically actuated MEMS devices. Numerical simulations and discussions indicate that the effects of instability, nonlinear characteristics and reliability subjected to electrostatic forces cannot be ignored and are in need of further investigation.

Implantable cardiac resynchronization therapy devices to monitor heart failure clinical status.

PubMed

Fung, Jeffrey Wing-Hong; Yu, Cheuk-Man

2007-03-01

Cardiac resynchronization therapy is a standard therapy for selected patients with heart failure. With advances in technology and storage capacity, the device acts as a convenient platform to provide valuable information about heart failure status in these high-risk patients. Unlike other modalities of investigation which may only allow one-off evaluation, heart failure status can be monitored by device diagnostics including heart rate variability, activity status, and intrathoracic impedance in a continuous basis. These parameters do not just provide long-term prognostic information but also may be useful to predict upcoming heart failure exacerbation. Prompt and early intervention may abort decompensation, prevent hospitalization, improve quality of life, and reduce health care cost. Moreover, this information may be applied to titrate the dosage of medication and monitor response to heart failure treatment. This review will focus on the prognostic and predictive values of heart failure status monitoring provided by these devices.

Disease management: remote monitoring in heart failure patients with implantable defibrillators, resynchronization devices, and haemodynamic monitors.

PubMed

Abraham, William T

2013-06-01

Heart failure represents a major public health concern, associated with high rates of morbidity and mortality. A particular focus of contemporary heart failure management is reduction of hospital admission and readmission rates. While optimal medical therapy favourably impacts the natural history of the disease, devices such as cardiac resynchronization therapy devices and implantable cardioverter defibrillators have added incremental value in improving heart failure outcomes. These devices also enable remote patient monitoring via device-based diagnostics. Device-based measurement of physiological parameters, such as intrathoracic impedance and heart rate variability, provide a means to assess risk of worsening heart failure and the possibility of future hospitalization. Beyond this capability, implantable haemodynamic monitors have the potential to direct day-to-day management of heart failure patients to significantly reduce hospitalization rates. The use of a pulmonary artery pressure measurement system has been shown to significantly reduce the risk of heart failure hospitalization in a large randomized controlled study, the CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial. Observations from a pilot study also support the potential use of a left atrial pressure monitoring system and physician-directed patient self-management paradigm; these observations are under further investigation in the ongoing LAPTOP-HF trial. All these devices depend upon high-intensity remote monitoring for successful detection of parameter deviations and for directing and following therapy.

Diagnostic yield of device interrogation in the evaluation of syncope in an elderly population.

PubMed

D'Angelo, Robert N; Pickett, Christopher C

2017-06-01

Device interrogation has become a standard part of the syncope evaluation for patients admitted with permanent pacemakers (PPM) or implantable cardiac defibrillators (ICD), although few studies have shown interrogation yields clinically useful data. The purpose of this study is to determine the diagnostic yield of device interrogation as well as other commonly performed tests in the workup of unexplained syncope in patients with previously implanted PPMs or ICDs. We retrospectively reviewed records of 88 patients admitted to our medical center for syncope with previously implanted pacemakers between January 1, 2005 and January 1, 2015 using ICD-9 billing data. Pacemaker interrogation demonstrated an arrhythmia as the cause for syncope in 4 patients (4%) and evidence of device failure secondary to perforation in 1 patient (1%). The cause of syncope was unknown in 34 patients (39%). Orthostatic hypotension was the most commonly identified cause of syncope (26%), followed by vasovagal syncope (13%), autonomic dysfunction (5%), ventricular arrhythmia (3%), atrial arrhythmia (2%), congestive heart failure (2%), stroke (2%), and other less common causes (8%). History was the most important determinant of syncope (36%), followed by orthostatic vital signs (14%), device interrogations (4%), head CT (2%), and transthoracic echocardiogram (1%). Device interrogation is rarely useful for elucidating a cause of syncope without concerning physical exam, telemetry, or EKG findings. Interrogation may occasionally yield paroxysmal arrhythmias responsible for syncopal episode, but these rarely alter clinical outcomes. Interrogation appears to be more useful in patients with syncope after recent device placement. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Thermo-piezo-electro-mechanical simulation of AlGaN (aluminum gallium nitride) / GaN (gallium nitride) High Electron Mobility Transistors

NASA Astrophysics Data System (ADS)

Stevens, Lorin E.

Due to the current public demand of faster, more powerful, and more reliable electronic devices, research is prolific these days in the area of high electron mobility transistor (HEMT) devices. This is because of their usefulness in RF (radio frequency) and microwave power amplifier applications including microwave vacuum tubes, cellular and personal communications services, and widespread broadband access. Although electrical transistor research has been ongoing since its inception in 1947, the transistor itself continues to evolve and improve much in part because of the many driven researchers and scientists throughout the world who are pushing the limits of what modern electronic devices can do. The purpose of the research outlined in this paper was to better understand the mechanical stresses and strains that are present in a hybrid AlGaN (Aluminum Gallium Nitride) / GaN (Gallium Nitride) HEMT, while under electrically-active conditions. One of the main issues currently being researched in these devices is their reliability, or their consistent ability to function properly, when subjected to high-power conditions. The researchers of this mechanical study have performed a static (i.e. frequency-independent) reliability analysis using powerful multiphysics computer modeling/simulation to get a better idea of what can cause failure in these devices. Because HEMT transistors are so small (micro/nano-sized), obtaining experimental measurements of stresses and strains during the active operation of these devices is extremely challenging. Physical mechanisms that cause stress/strain in these structures include thermo-structural phenomena due to mismatch in both coefficient of thermal expansion (CTE) and mechanical stiffness between different materials, as well as stress/strain caused by "piezoelectric" effects (i.e. mechanical deformation caused by an electric field, and conversely voltage induced by mechanical stress) in the AlGaN and GaN device portions (both piezoelectric materials). This piezoelectric effect can be triggered by voltage applied to the device's gate contact and the existence of an HEMT-unique "two-dimensional electron gas" (2DEG) at the GaN-AlGaN interface. COMSOL Multiphysics computer software has been utilized to create a finite element (i.e. piece-by-piece) simulation to visualize both temperature and stress/strain distributions that can occur in the device, by coupling together (i.e. solving simultaneously) the thermal, electrical, structural, and piezoelectric effects inherent in the device. The 2DEG has been modeled not with the typically-used self-consistent quantum physics analytical equations, rather as a combined localized heat source* (thermal) and surface charge density* (electrical) boundary condition. Critical values of stress/strain and their respective locations in the device have been identified. Failure locations have been estimated based on the critical values of stress and strain, and compared with reports in literature. The knowledge of the overall stress/strain distribution has assisted in determining the likely device failure mechanisms and possible mitigation approaches. The contribution and interaction of individual stress mechanisms including piezoelectric effects and thermal expansion caused by device self-heating (i.e. fast-moving electrons causing heat) have been quantified. * Values taken from results of experimental studies in literature.

Optical recording materials

NASA Astrophysics Data System (ADS)

Savant, Gajendra D.; Jannson, Joanna L.

1991-07-01

The increased emphasis on speed of operation, wavelength selectivity, compactness, and ruggedization has focused a great deal of attention on the solutions offered by all-optic devices and by hybrid electro-optic systems. In fact, many photonic devices are being considered for use as partial replacements for electronic systems. Optical components, which include modulators, switches, 3-D memory storage devices, wavelength division multiplexers, holographic optical elements, and others, are examples of such devices. The success or failure of these modern optical devices depends, to a great extent, on the performance and survivability of the optical materials used. This is particularly true for volume holographic filters, organic memory media, second- and third-order nonlinear material-based processors and neural networks. Due to the critical importance of these materials and their lack of availability, Physical Optics Corporation (POC) undertook a global advanced optical materials program which has enabled it to introduce several optical devices, based on the new and improved materials which will be described in this article.

Using the Minimally Invasive Impella 5.0 via the Right Subclavian Artery Cutdown for Acute on Chronic Decompensated Heart Failure as a Bridge to Decision.

PubMed

Bansal, Aditya; Bhama, Jay K; Patel, Rajan; Desai, Sapna; Mandras, Stacy A; Patel, Hamang; Collins, Tyrone; Reilly, John P; Ventura, Hector O; Parrino, P Eugene

2016-01-01

Outcomes of traditional mechanical support paradigms (extracorporeal membrane oxygenation, intraaortic balloon pump [IABP], and permanent left ventricular assist device [LVAD]) in acute decompensated heart failure have generally been suboptimal. Novel approaches, such as minimally invasive LVAD therapy (Impella 5.0 device), promise less invasive but equivalent hemodynamic support. However, it is yet unknown whether the outcomes with such devices support widespread acceptance of this new technology. We recently started utilizing the right subclavian artery (RSA) for Impella 5.0 implantation and report our early experience and outcomes with this novel approach. A single-center retrospective review was performed of 24 patients with acute on chronic decompensated heart failure who received the Impella 5.0 via the RSA from June 2011 to May 2014. The device was implanted via a cutdown through an 8-mm vascular graft sewn to the RSA. The device was positioned with fluoroscopy and transesophageal echocardiography. The mean age of the patients was 51.29 years, and 75% were male. At implantation, all patients were mechanically ventilated on at least 2 inotropes with persistent cardiogenic shock, and 17 (70.8%) were on IABP support. Postimplantation, 21 (87.5%) tolerated extubation, and all 17 of the patients with IABPs tolerated discontinuation of IABP support. The reduction in the Model for End-Stage Liver Disease score preimplantation vs postimplantation was statistically significant (21.17 vs 14.88, P=0.0014), suggesting improvement in end organ function. A significant decrease was also seen in creatinine levels before and after implantation (2.17 mg/dL vs 1.50 mg/dL, P=0.0043). The endpoint of support included recovery in 6 patients (25.0%), permanent LVAD in 9 (37.5%), and heart transplantation in 2 (8.3%). Death occurred in 7 patients (29.2%) as a result of multisystem organ failure, infection, or patient withdrawal of care. Minimally invasive LVAD therapy using the Impella 5.0 via the RSA cutdown is an attractive option in acute on chronic decompensated heart failure. Improvement in end organ function allows for transition to recovery or to advanced surgical therapies such as permanent LVAD and heart transplantation. Significant advantages to this approach include improved left ventricular unloading, lower anticoagulation need, and the potential for ambulation and physical therapy.

Using the Minimally Invasive Impella 5.0 via the Right Subclavian Artery Cutdown for Acute on Chronic Decompensated Heart Failure as a Bridge to Decision

PubMed Central

Bansal, Aditya; Bhama, Jay K.; Patel, Rajan; Desai, Sapna; Mandras, Stacy A.; Patel, Hamang; Collins, Tyrone; Reilly, John P.; Ventura, Hector O.; Parrino, P. Eugene

2016-01-01

Background: Outcomes of traditional mechanical support paradigms (extracorporeal membrane oxygenation, intraaortic balloon pump [IABP], and permanent left ventricular assist device [LVAD]) in acute decompensated heart failure have generally been suboptimal. Novel approaches, such as minimally invasive LVAD therapy (Impella 5.0 device), promise less invasive but equivalent hemodynamic support. However, it is yet unknown whether the outcomes with such devices support widespread acceptance of this new technology. We recently started utilizing the right subclavian artery (RSA) for Impella 5.0 implantation and report our early experience and outcomes with this novel approach. Methods: A single-center retrospective review was performed of 24 patients with acute on chronic decompensated heart failure who received the Impella 5.0 via the RSA from June 2011 to May 2014. The device was implanted via a cutdown through an 8-mm vascular graft sewn to the RSA. The device was positioned with fluoroscopy and transesophageal echocardiography. Results: The mean age of the patients was 51.29 years, and 75% were male. At implantation, all patients were mechanically ventilated on at least 2 inotropes with persistent cardiogenic shock, and 17 (70.8%) were on IABP support. Postimplantation, 21 (87.5%) tolerated extubation, and all 17 of the patients with IABPs tolerated discontinuation of IABP support. The reduction in the Model for End-Stage Liver Disease score preimplantation vs postimplantation was statistically significant (21.17 vs 14.88, P=0.0014), suggesting improvement in end organ function. A significant decrease was also seen in creatinine levels before and after implantation (2.17 mg/dL vs 1.50 mg/dL, P=0.0043). The endpoint of support included recovery in 6 patients (25.0%), permanent LVAD in 9 (37.5%), and heart transplantation in 2 (8.3%). Death occurred in 7 patients (29.2%) as a result of multisystem organ failure, infection, or patient withdrawal of care. Conclusion: Minimally invasive LVAD therapy using the Impella 5.0 via the RSA cutdown is an attractive option in acute on chronic decompensated heart failure. Improvement in end organ function allows for transition to recovery or to advanced surgical therapies such as permanent LVAD and heart transplantation. Significant advantages to this approach include improved left ventricular unloading, lower anticoagulation need, and the potential for ambulation and physical therapy. PMID:27660567

Control method for physical systems and devices

DOEpatents

Guckenheimer, John

1997-01-01

A control method for stabilizing systems or devices that are outside the control domain of a linear controller is provided. When applied to nonlinear systems, the effectiveness of this method depends upon the size of the domain of stability that is produced for the stabilized equilibrium. If this domain is small compared to the accuracy of measurements or the size of disturbances within the system, then the linear controller is likely to fail within a short period. Failure of the system or device can be catastrophic: the system or device can wander far from the desired equilibrium. The method of the invention presents a general procedure to recapture the stability of a linear controller, when the trajectory of a system or device leaves its region of stability. By using a hybrid strategy based upon discrete switching events within the state space of the system or device, the system or device will return from a much larger domain to the region of stability utilized by the linear controller. The control procedure is robust and remains effective under large classes of perturbations of a given underlying system or device.

Predicting device failure after percutaneous repair of functional mitral regurgitation in advanced heart failure: Implications for patient selection.

PubMed

Stolfo, Davide; De Luca, Antonio; Morea, Gaetano; Merlo, Marco; Vitrella, Giancarlo; Caiffa, Thomas; Barbati, Giulia; Rakar, Serena; Korcova, Renata; Perkan, Andrea; Pinamonti, Bruno; Pappalardo, Aniello; Berardini, Alessandra; Biagini, Elena; Saia, Francesco; Grigioni, Francesco; Rapezzi, Claudio; Sinagra, Gianfranco

2018-04-15

Patients with heart failure (HF) and severe symptomatic functional mitral regurgitation (FMR) may benefit from MitraClip implantation. With increasing numbers of patients being treated the success of procedure becomes a key issue. We sought to investigate the pre-procedural predictors of device failure in patients with advanced HF treated with MitraClip. From April 2012 to November 2016, 76 patients with poor functional class (NYHA class III-IV) and severe left ventricular (LV) remodeling underwent MitraClip implantation at University Hospitals of Trieste and Bologna (Italy). Device failure was assessed according to MVARC criteria. Patients were subsequently followed to additionally assess the patient success after 12months. Mean age was 67±12years, the mean Log-EuroSCORE was 23.4±16.5%, and the mean LV end-diastolic volume index and ejection fraction (EF) were 112±33ml/m 2 and 30.6±8.9%, respectively. At short-term evaluation, device failure was observed in 22 (29%) patients. Univariate predictors of device failure were LVEF, LV and left atrial volumes and anteroposterior mitral annulus diameter. Annulus dimension (OR 1.153, 95% CI 1.002-1.327, p=0.043) and LV end-diastolic volume (OR 1.024, 95% CI 1.000-1.049, p=0.049) were the only variables independently associated with the risk of device failure at the multivariate model. Pre-procedural anteroposterior mitral annulus diameter accurately predicted the risk of device failure after MitraClip in the setting of advanced HF. Its assessment might aid the selection of the best candidates to percutaneous correction of FMR. Copyright © 2018 Elsevier B.V. All rights reserved.

Charge collection and SEU mechanisms

NASA Astrophysics Data System (ADS)

Musseau, O.

1994-01-01

In the interaction of cosmic ions with microelectronic devices a dense electron-hole plasma is created along the ion track. Carriers are separated and transported by the electric field and under the action of the concentration gradient. The subsequent collection of these carriers induces a transient current at some electrical node of the device. This "ionocurrent" (single ion induced current) acts as any electrical perturbation in the device, propagating in the circuit and inducing failures. In bistable systems (registers, memories) the stored data can be upset. In clocked devices (microprocessors) the parasitic perturbation may propagate through the device to the outputs. This type of failure only effects the information, and do not degrade the functionally of the device. The purpose of this paper is to review the mechanisms of single event upset in microelectronic devices. Experimental and theoretical results are presented, and actual questions and problems are discussed. A brief introduction recalls the creation of the dense plasma of electron-hole pairs. The basic processes for charge collection in a simple np junction (drift and diffusion) are presented. The funneling-field effect is discussed and experimental results are compared to numerical simulations and semi-empirical models. Charge collection in actual microelectronic structures is then presented. Due to the parasitic elements, coupling effects are observed. Geometrical effects, in densely packed structures, results in multiple errors. Electronic couplings are due to the carriers in excess, acting as minority carriers, that trigger parasitic bipolar transistors. Single event upset of memory cells is discussed, based on numerical and experimental data. The main parameters for device characterization are presented. From the physical interpretation of charge collection mechanisms, the intrinsic sensitivity of various microelectronic technologies is determined and compared to experimental data. Scaling laws and future trends are finally discussed.

Impact of defects on the electrical transport, optical properties and failure mechanisms of GaN nanowires.

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

Armstrong, Andrew M.; Aubry, Sylvie; Shaner, Eric Arthur

2010-09-01

We present the results of a three year LDRD project that focused on understanding the impact of defects on the electrical, optical and thermal properties of GaN-based nanowires (NWs). We describe the development and application of a host of experimental techniques to quantify and understand the physics of defects and thermal transport in GaN NWs. We also present the development of analytical models and computational studies of thermal conductivity in GaN NWs. Finally, we present an atomistic model for GaN NW electrical breakdown supported with experimental evidence. GaN-based nanowires are attractive for applications requiring compact, high-current density devices such asmore » ultraviolet laser arrays. Understanding GaN nanowire failure at high-current density is crucial to developing nanowire (NW) devices. Nanowire device failure is likely more complex than thin film due to the prominence of surface effects and enhanced interaction among point defects. Understanding the impact of surfaces and point defects on nanowire thermal and electrical transport is the first step toward rational control and mitigation of device failure mechanisms. However, investigating defects in GaN NWs is extremely challenging because conventional defect spectroscopy techniques are unsuitable for wide-bandgap nanostructures. To understand NW breakdown, the influence of pre-existing and emergent defects during high current stress on NW properties will be investigated. Acute sensitivity of NW thermal conductivity to point-defect density is expected due to the lack of threading dislocation (TD) gettering sites, and enhanced phonon-surface scattering further inhibits thermal transport. Excess defect creation during Joule heating could further degrade thermal conductivity, producing a viscous cycle culminating in catastrophic breakdown. To investigate these issues, a unique combination of electron microscopy, scanning luminescence and photoconductivity implemented at the nanoscale will be used in concert with sophisticated molecular-dynamics calculations of surface and defect-mediated NW thermal transport. This proposal seeks to elucidate long standing material science questions for GaN while addressing issues critical to realizing reliable GaN NW devices.« less

Investigation of advanced fault insertion and simulator methods

NASA Technical Reports Server (NTRS)

Dunn, W. R.; Cottrell, D.

1986-01-01

The cooperative agreement partly supported research leading to the open-literature publication cited. Additional efforts under the agreement included research into fault modeling of semiconductor devices. Results of this research are presented in this report which is summarized in the following paragraphs. As a result of the cited research, it appears that semiconductor failure mechanism data is abundant but of little use in developing pin-level device models. Failure mode data on the other hand does exist but is too sparse to be of any statistical use in developing fault models. What is significant in the failure mode data is that, unlike classical logic, MSI and LSI devices do exhibit more than 'stuck-at' and open/short failure modes. Specifically they are dominated by parametric failures and functional anomalies that can include intermittent faults and multiple-pin failures. The report discusses methods of developing composite pin-level models based on extrapolation of semiconductor device failure mechanisms, failure modes, results of temperature stress testing and functional modeling. Limitations of this model particularly with regard to determination of fault detection coverage and latency time measurement are discussed. Indicated research directions are presented.

Ventricular assist devices and sleep-disordered breathing.

PubMed

Akkanti, Bindu; Castriotta, Richard J; Sayana, Pavani; Nunez, Emmanuel; Rajapreyar, Indranee; Kumar, Sachin; Nathan, Sriram; Majid, Ruckshanda

2017-10-01

Congestive heart failure is one of the leading causes of morbidity and mortality in the United States, and left ventricular assist devices have revolutionized treatment of end-stage heart failure. Given that sleep apnea results in significant morbidity in these patients with advanced heart failure, practicing sleep physicians need to have an understanding of left ventricular assist devices. In this review, we summarize what is known about ventricular assist devices as they relate to sleep medicine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-heating and failure in scalable graphene devices

DOE PAGES

Beechem, Thomas E.; Shaffer, Ryan A.; Nogan, John; ...

2016-06-09

Self-heating induced failure of graphene devices synthesized from both chemical vapor deposition (CVD) and epitaxial means is compared using a combination of infrared thermography and Raman imaging. Despite a larger thermal resistance, CVD devices dissipate >3x the amount of power before failure than their epitaxial counterparts. The discrepancy arises due to morphological irregularities implicit to the graphene synthesis method that induce localized heating. As a result, morphology, rather than thermal resistance, therefore dictates power handling limits in graphene devices.

Systematic Destruction of Electronic Parts for Aid in Electronic Failure Analysis

NASA Technical Reports Server (NTRS)

Decker, S. E.; Rolin, T. D.; McManus, P. D.

2012-01-01

NASA analyzes electrical, electronic, and electromechanical (EEE) parts used in space vehicles to understand failure modes of these components. Operational amplifiers and transistors are two examples of EEE parts critical to NASA missions that can fail due to electrical overstress (EOS). EOS is the result of voltage or current over time conditions that exceeds a component s specification limit. The objective of this study was to provide known voltage pulses over well-defined time intervals to determine the type and extent of damage imparted to the device. The amount of current was not controlled but measured so that pulse energy was determined. The damage was ascertained electrically using curve trace plots and optically using various metallographic techniques. The resulting data can be used to build a database of physical evidence to compare to damaged components removed from flight avionics. The comparison will provide the avionics failure analyst necessary information about voltage and times that caused flight or test failures when no other electrical data is available.

A bioprosthetic total artificial heart for end-stage heart failure: Results from a pilot study.

PubMed

Latrémouille, Christian; Carpentier, Alain; Leprince, Pascal; Roussel, Jean-Christian; Cholley, Bernard; Boissier, Elodie; Epailly, Eric; Capel, Antoine; Jansen, Piet; Smadja, David M

2018-01-01

The electro-hydraulically actuated Carmat total artificial heart (C-TAH) is designed to replace the heart in patients with end-stage heart failure, either as bridge to transplant or destination therapy. It provides pulsatile flow and contains bio-prosthetic blood contacting materials. A clinical feasibility study was conducted to evaluate the C-TAH safety and performance. Hospitalized patients, at imminent risk of death from irreversible biventricular failure despite optimal medical management, and not eligible for transplant or eligible but on extracorporeal life support, were enrolled. The primary endpoint was 30-days survival. Four patients were implanted with the C-TAH, three as destination therapy (ages 76, 68, 74) and one as bridge to transplant (age 58). They had implant times of 74, 270, 254 and 20 days respectively. All patients were free from hemolysis, clinical neurologic events, clinical evidence of thrombus and device-related infections. Hemodynamic and physical recovery allowed two patients to be discharged home for a cumulative duration of 7 months. The anticoagulation management strategy comprised initial unfractionated heparin, from postoperative day 2, followed by low molecular weight heparin and aspirin. An increased D-dimer level was observed in all patients during months 1 to 4. Temporary suspension of heparin anticoagulation resulted in thrombocytopenia and increased fibrin monomer, reversed by resuming anticoagulation with heparin. Causes of death were device-related (2 cases), respiratory failure and multi-organ failure. Preliminary clinical results with the C-TAH demonstrated good safety and performance profiles in patients suffering from biventricular failure, which need to be confirmed in a pivotal study. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Characterization and reliability of aluminum gallium nitride/gallium nitride high electron mobility transistors

NASA Astrophysics Data System (ADS)

Douglas, Erica Ann

Compound semiconductor devices, particularly those based on GaN, have found significant use in military and civilian systems for both microwave and optoelectronic applications. Future uses in ultra-high power radar systems will require the use of GaN transistors operated at very high voltages, currents and temperatures. GaN-based high electron mobility transistors (HEMTs) have proven power handling capability that overshadows all other wide band gap semiconductor devices for high frequency and high-power applications. Little conclusive research has been reported in order to determine the dominating degradation mechanisms of the devices that result in failure under standard operating conditions in the field. Therefore, it is imperative that further reliability testing be carried out to determine the failure mechanisms present in GaN HEMTs in order to improve device performance, and thus further the ability for future technologies to be developed. In order to obtain a better understanding of the true reliability of AlGaN/GaN HEMTs and determine the MTTF under standard operating conditions, it is crucial to investigate the interaction effects between thermal and electrical degradation. This research spans device characterization, device reliability, and device simulation in order to obtain an all-encompassing picture of the device physics. Initially, finite element thermal simulations were performed to investigate the effect of device design on self-heating under high power operation. This was then followed by a study of reliability of HEMTs and other tests structures during high power dc operation. Test structures without Schottky contacts showed high stability as compared to HEMTs, indicating that degradation of the gate is the reason for permanent device degradation. High reverse bias of the gate has been shown to induce the inverse piezoelectric effect, resulting in a sharp increase in gate leakage current due to crack formation. The introduction of elevated temperatures during high reverse gate bias indicated that device failure is due to the breakdown of an unintentional gate oxide. RF stress of AlGaN/GaN HEMTs showed comparable critical voltage breakdown regime as that of similar devices stressed under dc conditions. Though RF device characteristics showed stability up to a drain bias of 20 V, Schottky diode characteristics degraded substantially at all voltages investigated. Results from both dc and RF stress conditions, under several bias regimes, confirm that the primary root for stress induced degradation was due to the Schottky contact. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Optoelectronic Devices with Complex Failure Modes

NASA Technical Reports Server (NTRS)

Johnston, A.

2000-01-01

This part of the NSREC-2000 Short Course discusses radiation effects in basic photonic devices along with effects in more complex optoelectronic devices where the overall radiation response depends on several factors, with the possibility of multiple failure modes.

Mechanical Circulatory Support for Advanced Heart Failure: Are We about to Witness a New "Gold Standard"?

PubMed

Capoccia, Massimo

2016-12-12

The impact of left ventricular assist devices (LVADs) for the treatment of advanced heart failure has played a significant role as a bridge to transplant and more recently as a long-term solution for non-eligible candidates. Continuous flow left ventricular assist devices (CF-LVADs), based on axial and centrifugal design, are currently the most popular devices in view of their smaller size, increased reliability and higher durability compared to pulsatile flow left ventricular assist devices (PF-LVADs). The trend towards their use is increasing. Therefore, it has become mandatory to understand the physics and the mathematics behind their mode of operation for appropriate device selection and simulation set up. For this purpose, this review covers some of these aspects. Although very successful and technologically advanced, they have been associated with complications such as pump thrombosis, haemolysis, aortic regurgitation, gastro-intestinal bleeding and arterio-venous malformations. There is perception that the reduced arterial pulsatility may be responsible for these complications. A flow modulation control approach is currently being investigated in order to generate pulsatility in rotary blood pumps. Thrombus formation remains the most feared complication that can affect clinical outcome. The development of a preoperative strategy aimed at the reduction of complications and patient-device suitability may be appropriate. Patient-specific modelling based on 3D reconstruction from CT-scan combined with computational fluid dynamic studies is an attractive solution in order to identify potential areas of stagnation or challenging anatomy that could be addressed to achieve the desired outcome. The HeartMate II (axial) and the HeartWare HVAD (centrifugal) rotary blood pumps have been now used worldwide with proven outcome. The HeartMate III (centrifugal) is now emerging as the new promising device with encouraging preliminary results. There are now enough pumps on the market: it is time to focus on the complications in order to achieve the full potential and selling-point of this type of technology for the treatment of the increasing heart failure patient population.

In-situ microscale through-silicon via strain measurements by synchrotron x-ray microdiffraction exploring the physics behind data interpretation

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

Liu, Xi; School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332; Thadesar, Paragkumar A.

2014-09-15

In-situ microscale thermomechanical strain measurements have been performed in combination with synchrotron x-ray microdiffraction to understand the fundamental cause of failures in microelectronics devices with through-silicon vias. The physics behind the raster scan and data analysis of the measured strain distribution maps is explored utilizing the energies of indexed reflections from the measured data and applying them for beam intensity analysis and effective penetration depth determination. Moreover, a statistical analysis is performed for the beam intensity and strain distributions along the beam penetration path to account for the factors affecting peak search and strain refinement procedure.

Anesthesiology Devices; Reclassification of Membrane Lung for Long-Term Pulmonary Support; Redesignation as Extracorporeal Circuit and Accessories for Long-Term Respiratory/Cardiopulmonary Failure. Final order.

PubMed

2016-02-12

The Food and Drug Administration (FDA) is issuing a final order to redesignate membrane lung devices for long-term pulmonary support, a preamendments class III device, as extracorporeal circuit and accessories for long-term respiratory/cardiopulmonary failure, and to reclassify the device to class II (special controls) in patients with acute respiratory failure or acute cardiopulmonary failure where other available treatment options have failed, and continued clinical deterioration is expected or the risk of death is imminent. A membrane lung device for long-term pulmonary support (>6 hours) refers to the oxygenator in an extracorporeal circuit used during long-term procedures, commonly referred to as extracorporeal membrane oxygenation (ECMO). Because a number of other devices and accessories are used with the oxygenator in the circuit, the title and identification of the regulation are revised to include extracorporeal circuit and accessories for long-term respiratory/cardiopulmonary failure. Although an individual device or accessory used in an ECMO circuit may already have its own classification regulation when the device or accessory is intended for short-term use (<=6 hours), such device or accessory will be subject to the same regulatory controls applied to the oxygenator (i.e., class II, special controls) when evaluated as part of the ECMO circuit for long-term use (>6 hours). On its own initiative, based on new information, FDA is revising the classification of the membrane lung device for long-term pulmonary support.

Processes in construction of failure management expert systems from device design information

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Lance, Nick

1987-01-01

This paper analyzes the tasks and problem solving methods used by an engineer in constructing a failure management expert system from design information about the device to te diagnosed. An expert test engineer developed a trouble-shooting expert system based on device design information and experience with similar devices, rather than on specific expert knowledge gained from operating the device or troubleshooting its failures. The construction of the expert system was intensively observed and analyzed. This paper characterizes the knowledge, tasks, methods, and design decisions involved in constructing this type of expert system, and makes recommendations concerning tools for aiding and automating construction of such systems.

Representing functions/procedures and processes/structures for analysis of effects of failures on functions and operations

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Leifker, Daniel B.

1991-01-01

Current qualitative device and process models represent only the structure and behavior of physical systems. However, systems in the real world include goal-oriented activities that generally cannot be easily represented using current modeling techniques. An extension of a qualitative modeling system, known as functional modeling, which captures goal-oriented activities explicitly is proposed and how they may be used to support intelligent automation and fault management is shown.

Using diagnostic experiences in experience-based innovative design

NASA Astrophysics Data System (ADS)

Prabhakar, Sattiraju; Goel, Ashok K.

1992-03-01

Designing a novel class of devices requires innovation. Often, the design knowledge of these devices does not identify and address the constraints that are required for their performance in the real world operating environment. So any new design adapted from these devices tend to be similarly sketchy. In order to address this problem, we propose a case-based reasoning method called performance driven innovation (PDI). We model the design as a dynamic process, arrive at a design by adaptation from the known designs, generate failures for this design for some new constraints, and then use this failure knowledge to generate the required design knowledge for the new constraints. In this paper, we discuss two aspects of PDI: the representation of PDI cases and the translation of the failure knowledge into design knowledge for a constraint. Each case in PDI has two components: design and failure knowledge. Both of them are represented using a substance-behavior-function model. Failure knowledge has internal device failure behaviors and external environmental behaviors. The environmental behavior, for a constraint, interacting with the design behaviors, results in the failure internal behavior. The failure adaptation strategy generates functions, from the failure knowledge, which can be addressed using the routine design methods. These ideas are illustrated using a coffee-maker example.

High-Speed Device-Independent Quantum Random Number Generation without a Detection Loophole

NASA Astrophysics Data System (ADS)

Liu, Yang; Yuan, Xiao; Li, Ming-Han; Zhang, Weijun; Zhao, Qi; Zhong, Jiaqiang; Cao, Yuan; Li, Yu-Huai; Chen, Luo-Kan; Li, Hao; Peng, Tianyi; Chen, Yu-Ao; Peng, Cheng-Zhi; Shi, Sheng-Cai; Wang, Zhen; You, Lixing; Ma, Xiongfeng; Fan, Jingyun; Zhang, Qiang; Pan, Jian-Wei

2018-01-01

Quantum mechanics provides the means of generating genuine randomness that is impossible with deterministic classical processes. Remarkably, the unpredictability of randomness can be certified in a manner that is independent of implementation devices. Here, we present an experimental study of device-independent quantum random number generation based on a detection-loophole-free Bell test with entangled photons. In the randomness analysis, without the independent identical distribution assumption, we consider the worst case scenario that the adversary launches the most powerful attacks against the quantum adversary. After considering statistical fluctuations and applying an 80 Gb ×45.6 Mb Toeplitz matrix hashing, we achieve a final random bit rate of 114 bits /s , with a failure probability less than 10-5. This marks a critical step towards realistic applications in cryptography and fundamental physics tests.

Post irradiation effects (PIE) in integrated circuits

NASA Technical Reports Server (NTRS)

Shaw, D. C.; Lowry, L.; Barnes, C.; Zakharia, M.; Agarwal, S.; Rax, B.

1991-01-01

Post-irradiation effects (PIE) ranging from normal recovery to catastrophic failure have been observed in integrated circuits during the PIE period. Data presented show failure due to rebound after a 10 krad(Si) dose. In particular, five device types are investigated with varying PIE response. Special attention has been given to the HI1-507A analog multiplexer because its PIE response is extreme. X-ray diffraction has been uniquely employed to measure physical stress in the HI1-507A metallization. An attempt has been made to show a relationship between stress relaxation and radiation effects. All data presented support the current MIL-STD Method 1019.4 but demonstrate the importance of performing PIE measurements, even when mission doses are as low as 10 krad(Si).

Securing All intraVenous devices Effectively in hospitalised patients--the SAVE trial: study protocol for a multicentre randomised controlled trial.

PubMed

Rickard, Claire M; Marsh, Nicole; Webster, Joan; Playford, E Geoffrey; McGrail, Matthew R; Larsen, Emily; Keogh, Samantha; McMillan, David; Whitty, Jennifer A; Choudhury, Md Abu; Dunster, Kimble R; Reynolds, Heather; Marshall, Andrea; Crilly, Julia; Young, Jeanine; Thom, Ogilvie; Gowardman, John; Corley, Amanda; Fraser, John F

2015-09-23

Over 70% of all hospital admissions have a peripheral intravenous device (PIV) inserted; however, the failure rate of PIVs is unacceptably high, with up to 69% of these devices failing before treatment is complete. Failure can be due to dislodgement, phlebitis, occlusion/infiltration and/or infection. This results in interrupted medical therapy; painful phlebitis and reinsertions; increased hospital length of stay, morbidity and mortality from infections; and wasted medical/nursing time. Appropriate PIV dressing and securement may prevent many cases of PIV failure, but little comparative data exist regarding the efficacy of various PIV dressing and securement methods. This trial will investigate the clinical and cost-effectiveness of 4 methods of PIV dressing and securement in preventing PIV failure. A multicentre, parallel group, superiority randomised controlled trial with 4 arms, 3 experimental groups (tissue adhesive, bordered polyurethane dressing, sutureless securement device) and 1 control (standard polyurethane dressing) is planned. There will be a 3-year recruitment of 1708 adult patients, with allocation concealment until randomisation by a centralised web-based service. The primary outcome is PIV failure which includes any of: dislodgement, occlusion/infiltration, phlebitis and infection. Secondary outcomes include: types of PIV failure, PIV dwell time, costs, device colonisation, skin colonisation, patient and staff satisfaction. Relative incidence rates of device failure per 100 devices and per 1000 device days with 95% CIs will summarise the impact of each dressing, and test differences between groups. Kaplan-Meier survival curves (with log-rank Mantel-Cox test) will compare device failure over time. p Values of <0.05 will be considered significant. Secondary end points will be compared between groups using parametric or non-parametric techniques appropriate to level of measurement. Ethical approval has been received from Queensland Health (HREC/11/QRCH/152) and Griffith University (NRS/46/11/HREC). Results will be published according to the CONSORT statement and presented at relevant conferences. Australian New Zealand Clinical Trial Registry (ACTRN); 12611000769987. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Securing All intraVenous devices Effectively in hospitalised patients—the SAVE trial: study protocol for a multicentre randomised controlled trial

PubMed Central

Rickard, Claire M; Marsh, Nicole; Webster, Joan; Playford, E Geoffrey; McGrail, Matthew R; Larsen, Emily; Keogh, Samantha; McMillan, David; Whitty, Jennifer A; Choudhury, Md Abu; Dunster, Kimble R; Reynolds, Heather; Marshall, Andrea; Crilly, Julia; Young, Jeanine; Thom, Ogilvie; Gowardman, John; Corley, Amanda; Fraser, John F

2015-01-01

Introduction Over 70% of all hospital admissions have a peripheral intravenous device (PIV) inserted; however, the failure rate of PIVs is unacceptably high, with up to 69% of these devices failing before treatment is complete. Failure can be due to dislodgement, phlebitis, occlusion/infiltration and/or infection. This results in interrupted medical therapy; painful phlebitis and reinsertions; increased hospital length of stay, morbidity and mortality from infections; and wasted medical/nursing time. Appropriate PIV dressing and securement may prevent many cases of PIV failure, but little comparative data exist regarding the efficacy of various PIV dressing and securement methods. This trial will investigate the clinical and cost-effectiveness of 4 methods of PIV dressing and securement in preventing PIV failure. Methods and analysis A multicentre, parallel group, superiority randomised controlled trial with 4 arms, 3 experimental groups (tissue adhesive, bordered polyurethane dressing, sutureless securement device) and 1 control (standard polyurethane dressing) is planned. There will be a 3-year recruitment of 1708 adult patients, with allocation concealment until randomisation by a centralised web-based service. The primary outcome is PIV failure which includes any of: dislodgement, occlusion/infiltration, phlebitis and infection. Secondary outcomes include: types of PIV failure, PIV dwell time, costs, device colonisation, skin colonisation, patient and staff satisfaction. Relative incidence rates of device failure per 100 devices and per 1000 device days with 95% CIs will summarise the impact of each dressing, and test differences between groups. Kaplan-Meier survival curves (with log-rank Mantel-Cox test) will compare device failure over time. p Values of <0.05 will be considered significant. Secondary end points will be compared between groups using parametric or non-parametric techniques appropriate to level of measurement. Ethics and dissemination Ethical approval has been received from Queensland Health (HREC/11/QRCH/152) and Griffith University (NRS/46/11/HREC). Results will be published according to the CONSORT statement and presented at relevant conferences. Trial registration number Australian New Zealand Clinical Trial Registry (ACTRN); 12611000769987. PMID:26399574

Role of failure-mechanism identification in accelerated testing

NASA Technical Reports Server (NTRS)

Hu, J. M.; Barker, D.; Dasgupta, A.; Arora, A.

1993-01-01

Accelerated life testing techniques provide a short-cut method to investigate the reliability of electronic devices with respect to certain dominant failure mechanisms that occur under normal operating conditions. However, accelerated tests have often been conducted without knowledge of the failure mechanisms and without ensuring that the test accelerated the same mechanism as that observed under normal operating conditions. This paper summarizes common failure mechanisms in electronic devices and packages and investigates possible failure mechanism shifting during accelerated testing.

Evidence of Filamentary Switching in Oxide-based Memory Devices via Weak Programming and Retention Failure Analysis

NASA Astrophysics Data System (ADS)

Younis, Adnan; Chu, Dewei; Li, Sean

2015-09-01

Further progress in high-performance microelectronic devices relies on the development of novel materials and device architectures. However, the components and designs that are currently in use have reached their physical limits. Intensive research efforts, ranging from device fabrication to performance evaluation, are required to surmount these limitations. In this paper, we demonstrate that the superior bipolar resistive switching characteristics of a CeO2:Gd-based memory device can be manipulated by means of UV radiation, serving as a new degree of freedom. Furthermore, the metal oxide-based (CeO2:Gd) memory device was found to possess electrical and neuromorphic multifunctionalities. To investigate the underlying switching mechanism of the device, its plasticity behaviour was studied by imposing weak programming conditions. In addition, a short-term to long-term memory transition analogous to the forgetting process in the human brain, which is regarded as a key biological synaptic function for information processing and data storage, was realized. Based on a careful examination of the device’s retention behaviour at elevated temperatures, the filamentary nature of switching in such devices can be understood from a new perspective.

Evidence of Filamentary Switching in Oxide-based Memory Devices via Weak Programming and Retention Failure Analysis

PubMed Central

Younis, Adnan; Chu, Dewei; Li, Sean

2015-01-01

Further progress in high-performance microelectronic devices relies on the development of novel materials and device architectures. However, the components and designs that are currently in use have reached their physical limits. Intensive research efforts, ranging from device fabrication to performance evaluation, are required to surmount these limitations. In this paper, we demonstrate that the superior bipolar resistive switching characteristics of a CeO2:Gd-based memory device can be manipulated by means of UV radiation, serving as a new degree of freedom. Furthermore, the metal oxide-based (CeO2:Gd) memory device was found to possess electrical and neuromorphic multifunctionalities. To investigate the underlying switching mechanism of the device, its plasticity behaviour was studied by imposing weak programming conditions. In addition, a short-term to long-term memory transition analogous to the forgetting process in the human brain, which is regarded as a key biological synaptic function for information processing and data storage, was realized. Based on a careful examination of the device’s retention behaviour at elevated temperatures, the filamentary nature of switching in such devices can be understood from a new perspective. PMID:26324073

Analyses of Transistor Punchthrough Failures

NASA Technical Reports Server (NTRS)

Nicolas, David P.

1999-01-01

The failure of two transistors in the Altitude Switch Assembly for the Solid Rocket Booster followed by two additional failures a year later presented a challenge to failure analysts. These devices had successfully worked for many years on numerous missions. There was no history of failures with this type of device. Extensive checks of the test procedures gave no indication for a source of the cause. The devices were manufactured more than twenty years ago and failure information on this lot date code was not readily available. External visual exam, radiography, PEID, and leak testing were performed with nominal results Electrical testing indicated nearly identical base-emitter and base-collector characteristics (both forward and reverse) with a low resistance short emitter to collector. These characteristics are indicative of a classic failure mechanism called punchthrough. In failure analysis punchthrough refers to an condition where a relatively low voltage pulse causes the device to conduct very hard producing localized areas of thermal runaway or "hot spots". At one or more of these hot spots, the excessive currents melt the silicon. Heavily doped emitter material diffuses through the base region to the collector forming a diffusion pipe shorting the emitter to base to collector. Upon cooling, an alloy junction forms between the pipe and the base region. Generally, the hot spot (punch-through site) is under the bond and no surface artifact is visible. The devices were delidded and the internal structures were examined microscopically. The gold emitter lead was melted on one device, but others had anomalies in the metallization around the in-tact emitter bonds. The SEM examination confirmed some anomalies to be cosmetic defects while other anomalies were artifacts of the punchthrough site. Subsequent to these analyses, the contractor determined that some irregular testing procedures occurred at the time of the failures heretofore unreported. These testing irregularities involved the use of a breakout box and were the likely cause of the failures. There was no evidence to suggest a generic failure mechanism was responsible for the failure of these transistors.

Heart Failure and Frailty in the Community-Living Elderly Population: What the UFO Study Will Tell Us.

PubMed

Fung, Erik; Hui, Elsie; Yang, Xiaobo; Lui, Leong T; Cheng, King F; Li, Qi; Fan, Yiting; Sahota, Daljit S; Ma, Bosco H M; Lee, Jenny S W; Lee, Alex P W; Woo, Jean

2018-01-01

Heart failure and frailty are clinical syndromes that present with overlapping phenotypic characteristics. Importantly, their co-presence is associated with increased mortality and morbidity. While mechanical and electrical device therapies for heart failure are vital for select patients with advanced stage disease, the majority of patients and especially those with undiagnosed heart failure would benefit from early disease detection and prompt initiation of guideline-directed medical therapies. In this article, we review the problematic interactions between heart failure and frailty, introduce a focused cardiac screening program for community-living elderly initiated by a mobile communication device app leading to the Undiagnosed heart Failure in frail Older individuals (UFO) study, and discuss how the knowledge of pre-frailty and frailty status could be exploited for the detection of previously undiagnosed heart failure or advanced cardiac disease. The widespread use of mobile devices coupled with increasing availability of novel, effective medical and minimally invasive therapies have incentivized new approaches to heart failure case finding and disease management.

The pharmacotherapy of the HeartMate II, a continuous flow left ventricular assist device, in patients with advanced heart failure: integration of disease, device, and drug.

PubMed

Jennings, Douglas L; Chambers, Rachel M; Schillig, Jessica M

2010-10-01

Advanced heart failure continues to be a significant cause of morbidity and mortality in the US. Patients with advanced heart failure have a poor prognosis without cardiac transplantation. The use of left ventricular assist devices (LVADs) as destination therapy for these patients is therefore expected to increase in the coming years as technology advances. The HeartMate II, a continuous flow implantable device, is currently the only LVAD that has been approved by the Food and Drug Administration for destination therapy in patients with advanced heart failure. The pharmacotherapy associated with this device is very complex and, therefore, the need for expertly trained clinical pharmacists to care for this expanding patient population will also likely increase. Unfortunately, most pharmacists are unfamiliar with the effect of LVADs on the physiology and pharmacotherapy of a patient's heart failure. The purpose of this article is to give clinical pharmacists an introduction to the most common pharmacotherapeutic issues for patients with LVADs and present practical solutions for managing common drug therapy problems.

Physical and chemical analysis of lithium-ion battery cell-to-cell failure events inside custom fire chamber

NASA Astrophysics Data System (ADS)

Spinner, Neil S.; Field, Christopher R.; Hammond, Mark H.; Williams, Bradley A.; Myers, Kristina M.; Lubrano, Adam L.; Rose-Pehrsson, Susan L.; Tuttle, Steven G.

2015-04-01

A 5-cubic meter decompression chamber was re-purposed as a fire test chamber to conduct failure and abuse experiments on lithium-ion batteries. Various modifications were performed to enable remote control and monitoring of chamber functions, along with collection of data from instrumentation during tests including high speed and infrared cameras, a Fourier transform infrared spectrometer, real-time gas analyzers, and compact reconfigurable input and output devices. Single- and multi-cell packages of LiCoO2 chemistry 18650 lithium-ion batteries were constructed and data was obtained and analyzed for abuse and failure tests. Surrogate 18650 cells were designed and fabricated for multi-cell packages that mimicked the thermal behavior of real cells without using any active components, enabling internal temperature monitoring of cells adjacent to the active cell undergoing failure. Heat propagation and video recordings before, during, and after energetic failure events revealed a high degree of heterogeneity; some batteries exhibited short burst of sparks while others experienced a longer, sustained flame during failure. Carbon monoxide, carbon dioxide, methane, dimethyl carbonate, and ethylene carbonate were detected via gas analysis, and the presence of these species was consistent throughout all failure events. These results highlight the inherent danger in large format lithium-ion battery packs with regards to cell-to-cell failure, and illustrate the need for effective safety features.

A late and failure of airbag deployment case study for drivers of passenger cars in rear-end collisions

NASA Astrophysics Data System (ADS)

Toganel, George-Radu; Ovidiu Soica, Adrian

2017-10-01

The presented study was directed at two types of airbag miss-deployments: late deployment and non-deployment. Late deployment can be a product of override or underride road traffic accidents. Non-deployment can be a product of technical failure or trigger algorithm’s inability to correctly assume the state of the accident to happen. In order to analyse the phenomena through physical tests, a specialized test device was used for a series of 8 non-deployment tests and a series of 4 airbag firing tests, totalling 12 tests. Acceleration based data was recorded and analysed for the movement of the device part simulating the driver head. High speed video recording was used to analyse the mechanics of airbag deployment and correlate with the acceleration based data. It has been determined, in the limitations of the laboratory testing environment, a significant variation of the time frame for the airbag deployments, despite using similar testing conditions and identical tested products. Also, the initial time frame for airbag deployment delay was overshadowed by other factors such as time to impact.

Determining Functional Reliability of Pyrotechnic Mechanical Devices

NASA Technical Reports Server (NTRS)

Bement, Laurence J.; Multhaup, Herbert A.

1997-01-01

This paper describes a new approach for evaluating mechanical performance and predicting the mechanical functional reliability of pyrotechnic devices. Not included are other possible failure modes, such as the initiation of the pyrotechnic energy source. The requirement of hundreds or thousands of consecutive, successful tests on identical components for reliability predictions, using the generally accepted go/no-go statistical approach routinely ignores physics of failure. The approach described in this paper begins with measuring, understanding and controlling mechanical performance variables. Then, the energy required to accomplish the function is compared to that delivered by the pyrotechnic energy source to determine mechanical functional margin. Finally, the data collected in establishing functional margin is analyzed to predict mechanical functional reliability, using small-sample statistics. A careful application of this approach can provide considerable cost improvements and understanding over that of go/no-go statistics. Performance and the effects of variables can be defined, and reliability predictions can be made by evaluating 20 or fewer units. The application of this approach to a pin puller used on a successful NASA mission is provided as an example.

A conceptual definition of quality of life with a left ventricular assist device: results from a qualitative study.

PubMed

Sandau, Kristin E; Hoglund, Barbara A; Weaver, Carrie E; Boisjolie, Charlene; Feldman, David

2014-01-01

To develop a conceptual definition of quality of life (QoL) with a left ventricular assist device (LVAD). Conceptual and operational definitions of QoL with an LVAD are lacking. A grounded theory method was used. Adult, outpatient LVAD recipients (n = 11) participated twice in individual or paired interviews. A conceptual definition of QoL while living with an LVAD was established as: "Being well enough to do and enjoy day-to-day activities that are important to me." Participants described 5 important life domains consistent with QoL literature: physical, emotional, social, cognitive, and spiritual/meaning. However, participants identified unique concerns not addressed by generic or heart failure disease specific measures typically used in the LVAD population. Existing generic and heart-failure specific QoL measures are not adequate for understanding QoL among LVAD patients. Cognition and spiritual/meaning domains were significant; these need inclusion for comprehensive QoL assessment in the LVAD population. Copyright © 2014 Elsevier Inc. All rights reserved.

Modes of failure of Osteonics constrained tripolar implants: a retrospective analysis of forty-three failed implants.

PubMed

Guyen, Olivier; Lewallen, David G; Cabanela, Miguel E

2008-07-01

The Osteonics constrained tripolar implant has been one of the most commonly used options to manage recurrent instability after total hip arthroplasty. Mechanical failures were expected and have been reported. The purpose of this retrospective review was to identify the observed modes of failure of this device. Forty-three failed Osteonics constrained tripolar implants were revised at our institution between September 1997 and April 2005. All revisions related to the constrained acetabular component only were considered as failures. All of the devices had been inserted for recurrent or intraoperative instability during revision procedures. Seven different methods of implantation were used. Operative reports and radiographs were reviewed to identify the modes of failure. The average time to failure of the forty-three implants was 28.4 months. A total of five modes of failure were observed: failure at the bone-implant interface (type I), which occurred in eleven hips; failure at the mechanisms holding the constrained liner to the metal shell (type II), in six hips; failure of the retaining mechanism of the bipolar component (type III), in ten hips; dislocation of the prosthetic head at the inner bearing of the bipolar component (type IV), in three hips; and infection (type V), in twelve hips. The mode of failure remained unknown in one hip that had been revised at another institution. The Osteonics constrained tripolar total hip arthroplasty implant is a complex device involving many parts. We showed that failure of this device can occur at most of its interfaces. It would therefore appear logical to limit its application to salvage situations.

Reliability Prediction Models for Discrete Semiconductor Devices

DTIC Science & Technology

1988-07-01

influence failure rate were device construction, semiconductor material, junction temperature, electrical stress, circuit application., a plication...found to influence failure rate were device construction, semiconductor material, junction temperature, electrical stress, circuit application...MFA Airbreathlng 14issile, Flight MFF Missile, Free Flight ML Missile, Launch MMIC Monolithic Microwave Integrated Circuits MOS Metal-Oxide

Ampoule Failure System

NASA Technical Reports Server (NTRS)

Watring, Dale A. (Inventor); Johnson, Martin L. (Inventor)

1996-01-01

An ampoule failure system for use in material processing furnaces comprising a containment cartridge and an ampoule failure sensor. The containment cartridge contains an ampoule of toxic material therein and is positioned within a furnace for processing. An ampoule failure probe is positioned in the containment cartridge adjacent the ampoule for detecting a potential harmful release of toxic material therefrom during processing. The failure probe is spaced a predetermined distance from the ampoule and is chemically chosen so as to undergo a timely chemical reaction with the toxic material upon the harmful release thereof. The ampoule failure system further comprises a data acquisition system which is positioned externally of the furnace and is electrically connected to the ampoule failure probe so as to form a communicating electrical circuit. The data acquisition system includes an automatic shutdown device for shutting down the furnace upon the harmful release of toxic material. It also includes a resistance measuring device for measuring the resistance of the failure probe during processing. The chemical reaction causes a step increase in resistance of the failure probe whereupon the automatic shutdown device will responsively shut down the furnace.

Creating a model of diseased artery damage and failure from healthy porcine aorta.

PubMed

Noble, Christopher; Smulders, Nicole; Green, Nicola H; Lewis, Roger; Carré, Matt J; Franklin, Steve E; MacNeil, Sheila; Taylor, Zeike A

2016-07-01

Large quantities of diseased tissue are required in the research and development of new generations of medical devices, for example for use in physical testing. However, these are difficult to obtain. In contrast, porcine arteries are readily available as they are regarded as waste. Therefore, reliable means of creating from porcine tissue physical models of diseased human tissue that emulate well the associated mechanical changes would be valuable. To this end, we studied the effect on mechanical response of treating porcine thoracic aorta with collagenase, elastase and glutaraldehyde. The alterations in mechanical and failure properties were assessed via uniaxial tension testing. A constitutive model composed of the Gasser-Ogden-Holzapfel model, for elastic response, and a continuum damage model, for the failure, was also employed to provide a further basis for comparison (Calvo and Peña, 2006; Gasser et al., 2006). For the concentrations used here it was found that: collagenase treated samples showed decreased fracture stress in the axial direction only; elastase treated samples showed increased fracture stress in the circumferential direction only; and glutaraldehyde samples showed no change in either direction. With respect to the proposed constitutive model, both collagenase and elastase had a strong effect on the fibre-related terms. The model more closely captured the tissue response in the circumferential direction, due to the smoother and sharper transition from damage initiation to complete failure in this direction. Finally, comparison of the results with those of tensile tests on diseased tissues suggests that these treatments indeed provide a basis for creation of physical models of diseased arteries. Copyright © 2016 Elsevier Ltd. All rights reserved.

ESREF 98 - 9th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis

DTIC Science & Technology

1998-10-19

Gap effects within a nanosecond time scale. Effective Density of States Because of the limited possibility of compact Mobility models to deal with the...brackets) and the dislocation source action mobility M. The force is the balance between the normal stress a,, on the dislocations and the osmotic The...on, the electromigration force acts theration kt. on the atoms and a transport to the anode side of the t It is the mobility term that accounts for

Successful weaning of a left ventricular assist device implanted for ischemic heart failure.

PubMed

Beurtheret, Sylvain; Mordant, Pierre; Pavie, Alain; Leprince, Pascal

2010-10-01

We report the case of a patient stabilized under extra-corporeal membrane oxygenation after a refractory cardiogenic shock following myocardial infarction. Persistent left ventricular failure required secondary implantation of the left ventricular assist device (LVAD) HeartMate II. LVAD succeeded in the gradual recovery of myocardial contractility, allowing weaning of the device five months after implantation. Simultaneously, the patient beneficiated from coronary revascularization and resumed normal activity. This case emphasizes potential late recoveries after myocardial infarction complicated by left ventricular failure.

State-of-the-art implantable cardiac assist device therapy for heart failure: bridge to transplant and destination therapy.

PubMed

Park, S J; Kushwaha, S S; McGregor, C G A

2012-01-01

Congestive heart failure is associated with poor quality of life (QoL) and low survival rates. The development of state-of-the-art cardiac devices holds promise for improved therapy in patients with heart failure. The field of implantable cardiac assist devices is changing rapidly with the emergence of continuous-flow pumps (CFPs). The important developments in this field, including pertinent clinical trials, registry reports, innovative research, and potential future directions are discussed in this paper.

An Investigation in the Ames 40- by 80-Foot Wind Tunnel of a YT-56A Turboprop Engine Incorporating a Decoupler and a Controlled-Feathering Device

NASA Technical Reports Server (NTRS)

Rogallo, Vernon L.; Yaggy, Paul F.; McCloud, John L., III

1954-01-01

An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph. It was found that with neither device free to operate, the drag levels realized after power failures at airspeeds above 170 mph would impose vertical tail loads higher than those allowable for the YC-130, the airplane for which the test power package was designed. These levels were reached in approximately one second. The maximum drag realized after power failure was not appreciably altered by the use of the decoupler although the decoupler did put a limit on the duration of the peak drag. The controlled-feathering device maintained a level of essentially zero drag after power failure. The use of the decoupler in the YT-56A engine complicates windmilling air-starting procedures and makes it necessary to place operating restrictions on the engine to assure safe flight at low-power conditions,

Isopropyl Myristate-Modified Polyether-Urethane Coatings as Protective Barriers for Implantable Medical Devices

PubMed Central

Roohpour, Nima; Wasikiewicz, Jaroslaw M.; Moshaverinia, Alireza; Paul, Deepen; Rehman, Ihtesham U.; Vadgama, Pankaj

2009-01-01

Polyurethane films have potential applications in medicine, especially for packaging implantable medical devices. Although polyether-urethanes have superior mechanical properties and are biocompatible, achieving water resistance is still a challenge. Polyether based polyurethanes with two different molecular weights (PTMO1000, PTMO2000) were prepared from 4,4’-diphenylmethane diisocyanate and poly(tetra-methylene oxide). Polymer films were introduced using different concentrations (0.5-10 wt %) of isopropyl myristate lipid (IPM) as a non-toxic modifying agent. The physical and mechanical properties of these polymers were characterised using physical and spectroscopy techniques (FTIR, Raman, DSC, DMA, tensile testing). Water contact angle and water uptake of the membranes as a function of IPM concentration was also determined accordingly. The FTIR and Raman data indicate that IPM is dispersed in polyurethane at ≤ 2wt% and thermal analysis confirmed this miscibility to be dependent on soft segment length. Modified polymers showed increased tensile strength and failure strain as well as reduced water uptake by up to 24% at 1-2 wt% IPM.

Radiological Dispersion Devices and Basic Radiation Science

NASA Astrophysics Data System (ADS)

Bevelacqua, Joseph John

2010-05-01

Introductory physics courses present the basic concepts of radioactivity and an overview of nuclear physics that emphasizes the basic decay relationship and the various types of emitted radiation. Although this presentation provides insight into radiological science, it often fails to interest students to explore these concepts in a more rigorous manner. One reason for limited student interest is the failure to link the discussion to topics of current interest. The author has found that presenting this material with a link to radiological dispersion devices (RDDs), or dirty bombs, and their associated health effects provides added motivation for students. The events of Sept. 11, 2001, and periodic media focus on RDDs heighten student interest from both a scientific curiosity as well as a personal protection perspective. This article presents a framework for a more interesting discussion of the basics of radiation science and their associated health effects. The presentation can be integrated with existing radioactivity lectures or added as a supplementary or enrichment activity.

Needs of caregivers in heart failure management: A qualitative study

PubMed Central

Frost, Julia; Britten, Nicky; Jolly, Kate; Greaves, Colin; Abraham, Charles; Dalal, Hayes

2015-01-01

Objectives To identify the needs of caregivers supporting a person with heart failure and to inform the development of a caregiver resource to be used as part of a home-based self-management programme. Methods A qualitative study informed by thematic analysis involving 26 caregivers in individual interviews or a focus group. Results Three distinct aspects of caregiver support in heart failure management were identified. Firstly, caregivers identified needs about supporting management of heart failure including: coping with the variability of heart failure symptoms, what to do in an emergency, understanding and managing medicines, providing emotional support, promoting exercise and physical activity, providing personal care, living with a cardiac device and supporting depression management. Secondly, as they make the transition to becoming a caregiver, they need to develop skills to undertake difficult discussions about the role; communicate with health professionals; manage their own mental health, well-being and sleep; and manage home and work. Thirdly, caregivers require skills to engage social support, and voluntary and formal services while recognising that the long-term future is uncertain. Discussion The identification of the needs of caregiver has been used to inform the development of a home-based heart failure intervention facilitated by a trained health care practitioner. PMID:25795144

Risk assessment and comparative effectiveness of left ventricular assist device and medical management in ambulatory heart failure patients: design and rationale of the ROADMAP clinical trial.

PubMed

Rogers, Joseph G; Boyle, Andrew J; O'Connell, John B; Horstmanshof, Douglas A; Haas, Donald C; Slaughter, Mark S; Park, Soon J; Farrar, David J; Starling, Randall C

2015-02-01

Mechanical circulatory support is now a proven therapy for the treatment of patients with advanced heart failure and cardiogenic shock. The role for this therapy in patients with less severe heart failure is unknown. The objective of this study is to examine the impact of mechanically assisted circulation using the HeartMate II left ventricular assist device in patients who meet current US Food and Drug Administration-defined criteria for treatment but are not yet receiving intravenous inotropic therapy. This is a prospective, nonrandomized clinical trial of 200 patients treated with either optimal medical management or a mechanical circulatory support device. This trial will be the first prospective clinical evaluation comparing outcomes of patients with advanced ambulatory heart failure treated with either ongoing medical therapy or a left ventricular assist device. It is anticipated to provide novel insights regarding relative outcomes with each treatment and an understanding of patient and provider acceptance of the ventricular assist device therapy. This trial will also provide information regarding the risk of events in "stable" patients with advanced heart failure and guidance for the optimal timing of left ventricular assist device therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

Left ventricular assist device management in patients chronically supported for advanced heart failure.

PubMed

Cowger, Jennifer; Romano, Matthew A; Stulak, John; Pagani, Francis D; Aaronson, Keith D

2011-03-01

This review summarizes management strategies to reduce morbidity and mortality in heart failure patients supported chronically with implantable left ventricular assist devices (LVADs). As the population of patients supported with long-term LVADs has grown, patient selection, operative technique, and patient management strategies have been refined, leading to improved outcomes. This review summarizes recent findings on LVAD candidate selection, and discusses outpatient strategies to optimize device performance and heart failure management. It also reviews important device complications that warrant close outpatient monitoring. Managing patients on chronic LVAD support requires regular patient follow-up, multidisciplinary care teams, and frequent laboratory and echocardiographic surveillance to ensure optimal outcomes.

Model-Driven Safety Analysis of Closed-Loop Medical Systems

PubMed Central

Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup

2013-01-01

In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure. PMID:24177176

High-Speed Device-Independent Quantum Random Number Generation without a Detection Loophole.

PubMed

Liu, Yang; Yuan, Xiao; Li, Ming-Han; Zhang, Weijun; Zhao, Qi; Zhong, Jiaqiang; Cao, Yuan; Li, Yu-Huai; Chen, Luo-Kan; Li, Hao; Peng, Tianyi; Chen, Yu-Ao; Peng, Cheng-Zhi; Shi, Sheng-Cai; Wang, Zhen; You, Lixing; Ma, Xiongfeng; Fan, Jingyun; Zhang, Qiang; Pan, Jian-Wei

2018-01-05

Quantum mechanics provides the means of generating genuine randomness that is impossible with deterministic classical processes. Remarkably, the unpredictability of randomness can be certified in a manner that is independent of implementation devices. Here, we present an experimental study of device-independent quantum random number generation based on a detection-loophole-free Bell test with entangled photons. In the randomness analysis, without the independent identical distribution assumption, we consider the worst case scenario that the adversary launches the most powerful attacks against the quantum adversary. After considering statistical fluctuations and applying an 80  Gb×45.6  Mb Toeplitz matrix hashing, we achieve a final random bit rate of 114  bits/s, with a failure probability less than 10^{-5}. This marks a critical step towards realistic applications in cryptography and fundamental physics tests.

Model-Driven Safety Analysis of Closed-Loop Medical Systems.

PubMed

Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup

2012-10-26

In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure.

Failure Analysis of CCD Image Sensors Using SQUID and GMR Magnetic Current Imaging

NASA Technical Reports Server (NTRS)

Felt, Frederick S.

2005-01-01

During electrical testing of a Full Field CCD Image Senor, electrical shorts were detected on three of six devices. These failures occurred after the parts were soldered to the PCB. Failure analysis was performed to determine the cause and locations of these failures on the devices. After removing the fiber optic faceplate, optical inspection was performed on the CCDs to understand the design and package layout. Optical inspection revealed that the device had a light shield ringing the CCD array. This structure complicated the failure analysis. Alternate methods of analysis were considered, including liquid crystal, light and thermal emission, LT/A, TT/A SQUID, and MP. Of these, SQUID and MP techniques were pursued for further analysis. Also magnetoresistive current imaging technology is discussed and compared to SQUID.

The Effect of Preoperative Cognitive Behavior and Exercise Therapy for a Patient With an Implanted Left Ventricular Assist Device in Korea.

PubMed

Seo, Yong Gon; Park, Won Hah; Jeon, Eun Seok; Sung, Ji Dong; Jang, Mi Ja

2017-10-01

Left ventricular assist devices (LVADs) are used in patients with progressive heart failure symptoms to provide circulatory support. Patients with LVADs are referred to inpatient cardiac rehabilitation to prevent postoperative complications and improve aerobic capacity and quality of life. Preoperative exercise therapy for cardiac patients is an emerging treatment modality, and several studies have reported that it improves postoperative outcomes, such as length of hospital stay and postoperative complications. This case report describes the benefits of preoperative cognitive behavioral and exercise therapy in a Korean patient undergoing LVAD implantation. V. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Evaluation of the Linde Flow Warning Device,

DTIC Science & Technology

1965-12-30

the cause of the failure. It was not possible to disassemble the pressure switch or to determine the cause of failure. The warning device was...simple means of causing an actuat ion of a pressure switch . The sensing device used in the apparatus proved to be too del icate for the operat ion to

CONFIG: Qualitative simulation tool for analyzing behavior of engineering devices

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Basham, Bryan D.; Harris, Richard A.

1987-01-01

To design failure management expert systems, engineers mentally analyze the effects of failures and procedures as they propagate through device configurations. CONFIG is a generic device modeling tool for use in discrete event simulation, to support such analyses. CONFIG permits graphical modeling of device configurations and qualitative specification of local operating modes of device components. Computation requirements are reduced by focussing the level of component description on operating modes and failure modes, and specifying qualitative ranges of variables relative to mode transition boundaries. Simulation processing occurs only when modes change or variables cross qualitative boundaries. Device models are built graphically, using components from libraries. Components are connected at ports by graphical relations that define data flow. The core of a component model is its state transition diagram, which specifies modes of operation and transitions among them.

Analysis of a Memory Device Failure

NASA Technical Reports Server (NTRS)

Nicolas, David P.; Devaney, John; Gores, Mark; Dicken, Howard

1998-01-01

The recent failure of a vintage memory device presented a unique challenge to failure analysts. Normally device layouts, fabrication parameters and other technical information were available to assist the analyst in the analysis. However, this device was out of production for many years and the manufacturer was no longer in business, so the information was not available. To further complicate this analysis, the package leads were all but removed making additional electrical testing difficult. Under these conditions, new and innovative methods were used to analyze the failure. The external visual exam, radiography, PIND, and leak testing were performed with nominal results. Since electrical testing was precluded by the short lead lengths, the device was delidded to expose the internal structures for microscopic examination. No failure mechanism was identified. The available electrical data suggested an ESD or low level EOS type mechanism which left no visible surface damage. Due to parallel electrical paths, electrical probing on the chip failed to locate the failure site. Two non-destructive Scanning Electron Microscopy techniques, CIVA (Charge Induced Voltage Alteration) and EBIC (Electron Beam Induced Current), and a liquid crystal decoration technique which detects localized heating were employed to aid in the analysis. CIVA and EBIC isolated two faults in the input circuitry, and the liquid crystal technique further localized two hot spots in regions on two input gates. Removal of the glassivation and metallization revealed multiple failure sites located in the gate oxide of two input transistors suggesting machine (testing) induced damage.

Heart Failure and Frailty in the Community-Living Elderly Population: What the UFO Study Will Tell Us

PubMed Central

Fung, Erik; Hui, Elsie; Yang, Xiaobo; Lui, Leong T.; Cheng, King F.; Li, Qi; Fan, Yiting; Sahota, Daljit S.; Ma, Bosco H. M.; Lee, Jenny S. W.; Lee, Alex P. W.; Woo, Jean

2018-01-01

Heart failure and frailty are clinical syndromes that present with overlapping phenotypic characteristics. Importantly, their co-presence is associated with increased mortality and morbidity. While mechanical and electrical device therapies for heart failure are vital for select patients with advanced stage disease, the majority of patients and especially those with undiagnosed heart failure would benefit from early disease detection and prompt initiation of guideline-directed medical therapies. In this article, we review the problematic interactions between heart failure and frailty, introduce a focused cardiac screening program for community-living elderly initiated by a mobile communication device app leading to the Undiagnosed heart Failure in frail Older individuals (UFO) study, and discuss how the knowledge of pre-frailty and frailty status could be exploited for the detection of previously undiagnosed heart failure or advanced cardiac disease. The widespread use of mobile devices coupled with increasing availability of novel, effective medical and minimally invasive therapies have incentivized new approaches to heart failure case finding and disease management. PMID:29740330

Surgical approach to end-stage heart failure.

PubMed

Klotz, Stefan; Scheld, Hans H

2011-02-01

End-stage heart failure is a challenging disease with growing incidence. With decreasing heart transplant rates worldwide organ preserving therapies become, again, of interest. The purpose of the present review is to examine the potential challenges of surgical therapies in patients with end-stage heart failure. The gold-standard for end-stage heart failure is and will be cardiac transplantation. However, due to organ shortage this therapy is limited to a few patients. Therefore implantation of ventricular assist devices (VADs) or long-term minimal-invasive partial support devices will increase. Improvements in device design with smaller devices, easier implantation techniques, and modified anticoagulation outcome and long-term success will likely improve. In addition, good quality of life as destination therapy is almost available. Organ conservation surgery (coronary artery bypass grafting and surgical ventricular restoration or surgical repair of mitral valve regurgitation) in end-stage heart failure patients could not prove the expected results. Transcatheter or minimal-invasive approaches of these therapies might become routine in the near future. Due to the overwhelming outcome rates, cardiac transplantation is the most established surgical therapy for end-stage heart failure. VAD therapy is increasing and minimized VADs might further open the market for destination therapy/permanent support.

Twin-tailed fail-over for fileservers maintaining full performance in the presence of a failure

DOEpatents

Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.

2008-02-12

A method for maintaining full performance of a file system in the presence of a failure is provided. The file system having N storage devices, where N is an integer greater than zero and N primary file servers where each file server is operatively connected to a corresponding storage device for accessing files therein. The file system further having a secondary file server operatively connected to at least one of the N storage devices. The method including: switching the connection of one of the N storage devices to the secondary file server upon a failure of one of the N primary file servers; and switching the connections of one or more of the remaining storage devices to a primary file server other than the failed file server as necessary so as to prevent a loss in performance and to provide each storage device with an operating file server.

Disaster preparedness for technology and electricity-dependent children and youth with special health care needs.

PubMed

Sakashita, Kazumi; Matthews, Wallace J; Yamamoto, Loren G

2013-06-01

Children and youth with special health care needs (CYSHCN) are complex and often dependent on electrical devices (technoelectric dependent) for life support/maintenance. Because they are reliant on electricity and electricity failure is common, the purpose of this study was to survey their preparedness for electricity failure. Parents and caregivers of technoelectric CYSHCN were asked to complete a preparedness questionnaire. We collected a convenience sample of 50 patients. These 50 patients utilized a total of 166 electrical devices. A home ventilator, oxygen concentrator, and a feeding pump were identified as the most important device for the children in 35 of the 50 patients, yet only 19 of the 35 patients could confirm that this device had a battery backup. Also, 22 of the 50 patients had a prolonged power failure preparedness plan. Technoelectric-dependent CYSHCN are poorly prepared for electrical power failure.

System and method for floating-substrate passive voltage contrast

DOEpatents

Jenkins, Mark W [Albuquerque, NM; Cole, Jr., Edward I.; Tangyunyong, Paiboon [Albuquerque, NM; Soden, Jerry M [Placitas, NM; Walraven, Jeremy A [Albuquerque, NM; Pimentel, Alejandro A [Albuquerque, NM

2009-04-28

A passive voltage contrast (PVC) system and method are disclosed for analyzing ICs to locate defects and failure mechanisms. During analysis a device side of a semiconductor die containing the IC is maintained in an electrically-floating condition without any ground electrical connection while a charged particle beam is scanned over the device side. Secondary particle emission from the device side of the IC is detected to form an image of device features, including electrical vias connected to transistor gates or to other structures in the IC. A difference in image contrast allows the defects or failure mechanisms be pinpointed. Varying the scan rate can, in some instances, produce an image reversal to facilitate precisely locating the defects or failure mechanisms in the IC. The system and method are useful for failure analysis of ICs formed on substrates (e.g. bulk semiconductor substrates and SOI substrates) and other types of structures.

An overview of the regulatory aspects of medical devices from the viewpoint of research and device manufacturing.

PubMed

Patrick, J

1993-01-01

To review the Food and Drug Administration's regulatory requirements for bringing a new or substantially changed medical device to market in the United States, noting the history and current requirements for the continuous spinal catheter. The relevant laws and guidelines for classifying, testing, and submitting a device to Food and Drug Administration approval are reviewed. The Food and Drug Administration categorizes medical devices into three classes, based on potential risk for illness or injury presented by a malfunction or failure. Class III devices are the most critical ones, and require a Premarket Approval that includes clinical trials before market introduction. Classes I and II usually require a 510(k), or premarket notification, which usually does not need any clinical data. Testing requirements include biocompatibility testing; physical, functional, and packaging testing; and sterility testing. The continuous spinal catheter (25-32 gauge) was marketed under a 510(k) claiming substantial equivalence to the Bizzarri-Giuffrida 24-gauge catheter, which was a pre-Amendment device. After incidences of cauda equina syndrome were reported with use of the continuous spinal technique, the Food and Drug Administration reclassified the small-gauge catheters as Class III devices, which require a Premarket Approval before being marketed.

Random numbers certified by Bell's theorem.

PubMed

Pironio, S; Acín, A; Massar, S; de la Giroday, A Boyer; Matsukevich, D N; Maunz, P; Olmschenk, S; Hayes, D; Luo, L; Manning, T A; Monroe, C

2010-04-15

Randomness is a fundamental feature of nature and a valuable resource for applications ranging from cryptography and gambling to numerical simulation of physical and biological systems. Random numbers, however, are difficult to characterize mathematically, and their generation must rely on an unpredictable physical process. Inaccuracies in the theoretical modelling of such processes or failures of the devices, possibly due to adversarial attacks, limit the reliability of random number generators in ways that are difficult to control and detect. Here, inspired by earlier work on non-locality-based and device-independent quantum information processing, we show that the non-local correlations of entangled quantum particles can be used to certify the presence of genuine randomness. It is thereby possible to design a cryptographically secure random number generator that does not require any assumption about the internal working of the device. Such a strong form of randomness generation is impossible classically and possible in quantum systems only if certified by a Bell inequality violation. We carry out a proof-of-concept demonstration of this proposal in a system of two entangled atoms separated by approximately one metre. The observed Bell inequality violation, featuring near perfect detection efficiency, guarantees that 42 new random numbers are generated with 99 per cent confidence. Our results lay the groundwork for future device-independent quantum information experiments and for addressing fundamental issues raised by the intrinsic randomness of quantum theory.

Understanding the mechanisms leading to failure in metallic nanowire-based transparent heaters, and solution for stability enhancement

NASA Astrophysics Data System (ADS)

Lagrange, M.; Sannicolo, T.; Muñoz-Rojas, D.; Guillo Lohan, B.; Khan, A.; Anikin, M.; Jiménez, C.; Bruckert, F.; Bréchet, Y.; Bellet, D.

2017-02-01

Silver nanowire (AgNW) networks are emerging as one of the most promising alternatives to indium tin oxide (ITO) for transparent electrodes in flexible electronic devices. They can be used in a variety of optoelectronic applications such as solar cells, touch panels and organic light-emitting diodes. Recently they have also proven to be very efficient when used as transparent heaters (THs). In addition to the study of AgNW networks acting as THs in regular use, i.e. at low voltage and moderate temperature, their stability and physical behavior at higher voltages and for longer durations should be studied in view of their integration into real devices. The properties of AgNW networks deposited by spray coating on glass or flexible transparent substrates are thoroughly studied via in situ measurements. The AgNW networks’ behavior at different voltages for different durations and under different atmospheric conditions, both in air and under vacuum, has been examined. At low voltage, a reversible electrical response is observed while irreversibility and even failure are observed at higher voltages. In order to gain a deeper insight into the behavior of AgNW networks used as THs, simple but realistic physical models are proposed and are found to be in fair agreement with the experimental data. Finally, as the stability of AgNW networks is a key issue, we demonstrate that coating AgNW networks with a very thin layer of TiO2 using atomic layer deposition (ALD) improves the material’s resistance against electrical and thermal instabilities without altering optical transmittance. We show that the critical annealing temperature associated to network breakdown increases from 270 °C for the as-deposited AgNW networks to 420 °C for AgNW networks coated with TiO2. Similarly, the electrical failure which occurs at 7 V for the as-deposited networks increases to 13 V for TiO2-coated networks. TiO2 is also proved to stabilize AgNW networks during long duration operation and at high voltage. Temperature higher than 235 °C was achieved at 7 V without failure.

Substantial harm associated with failure of chronic paediatric central venous access devices.

PubMed

Ullman, Amanda J; Kleidon, Tricia; Cooke, Marie; Rickard, Claire M

2017-07-06

Central venous access devices (CVADs) form an important component of modern paediatric healthcare, especially for children with chronic health conditions such as cancer or gastrointestinal disorders. However device failure and complications rates are high.Over 2½ years, a child requiring parenteral nutrition and associated vascular access dependency due to 'short gut syndrome' (intestinal failure secondary to gastroschisis and resultant significant bowel resection) had ten CVADs inserted, with ninesubsequently failing. This resulted in multiple anaesthetics, invasive procedures, injuries, vascular depletion, interrupted nutrition, delayed treatment and substantial healthcare costs. A conservative estimate of the institutional costs for each insertion, or rewiring, of her tunnelled CVAD was $A10 253 (2016 Australian dollars).These complications and device failures had significant negative impact on the child and her family. Considering the commonality of conditions requiring prolonged vascular access, these failures also have a significant impact on international health service costs. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Intermittent output failure of a VVI device due to the disintegration of the generator.

PubMed

Böhm, A; Kayser, S; Pintér, A; Préda, I

2001-01-01

The metal case and the header of a Biovallees Coralite 247 pacemaker fell apart in a patient resulting in syncope due to myopotential inhibition. Upon recalling our patients with that type of device, we found a similar technological failure in 11 of 16 of them. This finding warrants a consideration for recalling that Biovallees device.

Outcomes of patients with right ventricular failure on milrinone after left ventricular assist device implantation.

PubMed

Tsiouris, Athanasios; Paone, Gaetano; Brewer, Robert J; Nemeh, Hassan W; Borgi, Jamil; Morgan, Jeffrey A

2015-01-01

Previous studies have grouped together both patients requiring right ventricular assist devices (RVADs) with patients requiring prolonged milrinone therapy after left ventricular assist device (LVAD) implantation. We retrospectively identified 149 patients receiving LVADs and 18 (12.1%) of which developed right ventricular (RV) failure. We then separated these patients into those requiring RVADs versus prolonged milrinone therapy. This included 10 patients who were treated with prolonged milrinone and eight patients who underwent RVAD placement. Overall, the RV failure group had worse survival compared with the non-RV failure cohort (p = 0.038). However, this was only for the subgroup of patients who required RVADs, who had a 1, 6, 12, and 24 month survival of 62.5%, 37.5%, 37.5%, and 37.5%, respectively, versus 96.8%, 92.1%, 86.7%, and 84.4% for patients without RV failure (p < 0.001). Patients treated with prolonged milrinone therapy for RV failure had similar survivals compared with patients without RV failure. In the RV failure group, age, preoperative renal failure, and previous cardiac surgery were predictors of the need for prolonged postoperative milrinone. As LVADs become a more widely used therapy for patients with refractory, end-stage heart failure, it will be important to reduce the incidence of RV failure, as it yields significant morbidity and increases cost.

Storage reliability analysis summary report. Volume 2: Electro mechanical devices

NASA Astrophysics Data System (ADS)

Smith, H. B., Jr.; Krulac, I. L.

1982-09-01

This document summarizes storage reliability data collected by the US Army Missile Command on electro-mechanical devices over a period of several years. Sources of data are detailed, major failure modes and mechanisms are listed and discussed. Non-operational failure rate prediction methodology is given, and conclusions and recommendations for enhancing the storage reliability of devices are drawn from the analysis of collected data.

Functional Interrupts and Destructive Failures from Single Event Effect Testing of Point-Of-Load Devices

NASA Technical Reports Server (NTRS)

Chen, Dakai; Phan, Anthony; Kim, Hak; Swonger, James; Musil, Paul; LaBel, Kenneth

2013-01-01

We show examples of single event functional interrupt and destructive failure in modern POL devices. The increasing complexity and diversity of the design and process introduce hard SEE modes that are triggered by various mechanisms.

Inherent Risk or Risky Decision? Coach's Failure to Use Safety Device an Assumed Risk

ERIC Educational Resources Information Center

Dodds, Mark A.; Bochicchio, Kristi Schoepfer

2013-01-01

The court examined whether a coach's failure to implement a safety device during pitching practice enhanced the risk to the athlete or resulted in a suboptimal playing condition, in the context of the assumption of risk doctrine.

Microcircuit Device Reliability Memory/Digital LSI

DTIC Science & Technology

1982-01-01

has been performed. Each failure event record reveals the particular device and test characteristics, as well as associated stress values and other...given by: « s logio (Vxp) where X0 is the observed failure rate Xp is the predicted failure rate « is the residual Values of « are then plotted...n...... ||^||tpMMMWiWMM*i»""l’’൓ iŕŕ" ’• of failures per point). Some "funnelling" in Figure 17 shows this, although there is a fair amount of

Single event induced transients in I/O devices - A characterization

NASA Technical Reports Server (NTRS)

Newberry, D. M.; Kaye, D. H.; Soli, G. A.

1990-01-01

The results of single-event upset (SEU) testing performed to evaluate the parametric transients, i.e., amplitude and duration, in several I/O devices, and the impact of these transients are discussed. The failure rate of these devices is dependent on the susceptibility of interconnected devices to the resulting transient change in the output of the I/O device. This failure rate, which is a function of the susceptibility of the interconnected device as well as the SEU response of the I/O device itself, may be significantly different from an upset rate calculated without taking these factors into account. The impact at the system level is discussed by way of an example.

Percutaneous Ventricular Assist Devices: New Deus Ex Machina?

PubMed Central

Arroyo, Diego; Cook, Stéphane

2011-01-01

The development of ventricular assist devices has broadened the means with which one can treat acute heart failure. Percutaneous ventricular assist devices (pVAD) have risen from recent technological advances. They are smaller, easier, and faster to implant, all important qualities in the setting of acute heart failure. The present paper briefly describes the functioning and assets of the most common devices used today. It gives an overview of the current evidence and indications for left ventricular assist device use in cardiogenic shock and high-risk percutaneous coronary intervention. Finally, extracorporeal life support devices are dealt with in the setting of hemodynamic support. PMID:22091361

Machines versus medication for biventricular heart failure: focus on the total artificial heart.

PubMed

Arabia, Francisco A; Moriguchi, Jaime D

2014-09-01

The medical/surgical management of advanced heart failure has evolved rapidly over the last few decades. With better understanding of heart failure pathophysiology, new pharmacological agents have been introduced that have resulted in improvements in survival. For those patients that fail to improve, mechanical circulatory support with left ventricular assist devices and total artificial hearts (TAHs) have served as a beneficial bridge to transplantation. The TAH has continued to play a significant role as a bridge to transplantation in patients with biventricular failure and more selected indications that could not be completely helped with left ventricular assist devices. Improved survival with the TAH has resulted in more patients benefiting from this technology. Improvements will eventually lead to a totally implantable device that will permanently replace the failing human heart.

Cyber-Physical System Security With Deceptive Virtual Hosts for Industrial Control Networks

DOE PAGES

Vollmer, Todd; Manic, Milos

2014-05-01

A challenge facing industrial control network administrators is protecting the typically large number of connected assets for which they are responsible. These cyber devices may be tightly coupled with the physical processes they control and human induced failures risk dire real-world consequences. Dynamic virtual honeypots are effective tools for observing and attracting network intruder activity. This paper presents a design and implementation for self-configuring honeypots that passively examine control system network traffic and actively adapt to the observed environment. In contrast to prior work in the field, six tools were analyzed for suitability of network entity information gathering. Ettercap, anmore » established network security tool not commonly used in this capacity, outperformed the other tools and was chosen for implementation. Utilizing Ettercap XML output, a novel four-step algorithm was developed for autonomous creation and update of a Honeyd configuration. This algorithm was tested on an existing small campus grid and sensor network by execution of a collaborative usage scenario. Automatically created virtual hosts were deployed in concert with an anomaly behavior (AB) system in an attack scenario. Virtual hosts were automatically configured with unique emulated network stack behaviors for 92% of the targeted devices. The AB system alerted on 100% of the monitored emulated devices.« less

Quality of life assessment in the randomized PROTECT AF (Percutaneous Closure of the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation) trial of patients at risk for stroke with nonvalvular atrial fibrillation.

PubMed

Alli, Oluseun; Doshi, Shepal; Kar, Saibal; Reddy, Vivek; Sievert, Horst; Mullin, Chris; Swarup, Vijay; Whisenant, Brian; Holmes, David

2013-04-30

This study sought to assess quality of life parameters in a subset of patients enrolled in the PROTECT AF (Percutaneous Closure of the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation) trial. The PROTECT AF (Percutaneous Closure of the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation) trial demonstrated that in patients with nonvalvular atrial fibrillation (AF) and CHADS2 (congestive heart failure, hypertension, age, diabetes mellitus, and prior stroke, transient ischemic attack, or thromboembolism) score ≥1, a left atrial appendage closure device is noninferior to long-term warfarin for stroke prevention. Given this equivalency, quality of life (QOL) indicators are an important metric for evaluating these 2 different strategies. QOL using the Short-Form 12 Health Survey, version 2, measurement tool was obtained at baseline and 12 months in a subset of 547 patients in the PROTECT AF trial (361 device and 186 warfarin patients). The analysis cohort consisted of patients for whom either paired quality of life data were available after 12 months of follow-up or for patients who died. With the device, the total physical score improved in 34.9% and was unchanged in 29.9% versus warfarin in whom 24.7% were improved and 31.7% were unchanged (p = 0.01). Mental health improvement occurred in 33.0% of the device group versus 22.6% in the warfarin group (p = 0.06). There was a significant improvement in QOL in patients randomized to device for total physical score, physical function, and in physical role limitation compared to control. There were significant differences in the change in total physical score among warfarin naive and not-warfarin naive subgroups in the device group compared to control, but larger gains were seen with the warfarin naive subgroup with a 12-month change of 1.3 ± 8.8 versus -3.6 ± 6.7 (p = 0.0004) device compared to warfarin. Patients with nonvalvular AF at risk for stroke treated with left atrial appendage closure have favorable QOL changes at 12 months versus patients treated with warfarin. (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation [WATCHMAN PROTECT]; NCT00129545). Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Predictive modeling for corrective maintenance of imaging devices from machine logs.

PubMed

Patil, Ravindra B; Patil, Meru A; Ravi, Vidya; Naik, Sarif

2017-07-01

In the cost sensitive healthcare industry, an unplanned downtime of diagnostic and therapy imaging devices can be a burden on the financials of both the hospitals as well as the original equipment manufacturers (OEMs). In the current era of connectivity, it is easier to get these devices connected to a standard monitoring station. Once the system is connected, OEMs can monitor the health of these devices remotely and take corrective actions by providing preventive maintenance thereby avoiding major unplanned downtime. In this article, we present an overall methodology of predicting failure of these devices well before customer experiences it. We use data-driven approach based on machine learning to predict failures in turn resulting in reduced machine downtime, improved customer satisfaction and cost savings for the OEMs. One of the use-case of predicting component failure of PHILIPS iXR system is explained in this article.

Very high-cycle fatigue failure in micron-scale polycrystalline silicon films: Effects of environment and surface oxide thickness

NASA Astrophysics Data System (ADS)

Alsem, D. H.; Timmerman, R.; Boyce, B. L.; Stach, E. A.; De Hosson, J. Th. M.; Ritchie, R. O.

2007-01-01

Fatigue failure in micron-scale polycrystalline silicon structural films, a phenomenon that is not observed in bulk silicon, can severely impact the durability and reliability of microelectromechanical system devices. Despite several studies on the very high-cycle fatigue behavior of these films (up to 1012cycles), there is still an on-going debate on the precise mechanisms involved. We show here that for devices fabricated in the multiuser microelectromechanical system process (MUMPs) foundry and Sandia Ultra-planar, Multi-level MEMS Technology (SUMMiT V™) process and tested under equi-tension/compression loading at ˜40kHz in different environments, stress-lifetime data exhibit similar trends in fatigue behavior in ambient room air, shorter lifetimes in higher relative humidity environments, and no fatigue failure at all in high vacuum. The transmission electron microscopy of the surface oxides in the test samples shows a four- to sixfold thickening of the surface oxide at stress concentrations after fatigue failure, but no thickening after overload fracture in air or after fatigue cycling in vacuo. We find that such oxide thickening and premature fatigue failure (in air) occur in devices with initial oxide thicknesses of ˜4nm (SUMMiT V™) as well as in devices with much thicker initial oxides ˜20nm (MUMPs). Such results are interpreted and explained by a reaction-layer fatigue mechanism. Specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure of the entire device. The entirety of the evidence presented here strongly indicates that the reaction-layer fatigue mechanism is the governing mechanism for fatigue failure in micron-scale polycrystalline silicon thin films.

Nasal Jet-CPAP (variable flow) versus Bubble-CPAP in preterm infants with respiratory distress: an open label, randomized controlled trial.

PubMed

Bhatti, A; Khan, J; Murki, S; Sundaram, V; Saini, S S; Kumar, P

2015-11-01

To compare the failure rates between Jet continuous positive airway pressure device (J-CPAP-variable flow) and Bubble continuous positive airway device (B-CPAP) in preterm infants with respiratory distress. Preterm newborns <34 weeks gestation with onset of respiratory distress within 6 h of life were randomized to receive J-CPAP (a variable flow device) or B-CPAP (continuous flow device). A standardized protocol was followed for titration, weaning and removal of CPAP. Pressure was monitored close to the nares in both the devices every 6 hours and settings were adjusted to provide desired CPAP. The primary outcome was CPAP failure rate within 72 h of life. Secondary outcomes were CPAP failure within 7 days of life, need for surfactant post-randomization, time to CPAP failure, duration of CPAP and complications of prematurity. An intention to treat analysis was done. One-hundred seventy neonates were randomized, 80 to J-CPAP and 90 to B-CPAP. CPAP failure rates within 72 h were similar in infants who received J-CPAP and in those who received B-CPAP (29 versus 21%; relative risks 1.4 (0.8 to 2.3), P=0.25). Mean (95% confidence intervals) time to CPAP failure was 59 h (54 to 64) in the Jet CPAP group in comparison with 65 h (62 to 68) in the Bubble CPAP group (log rank P=0.19). All other secondary outcomes were similar between the two groups. In preterm infants with respiratory distress starting within 6 h of life, CPAP failure rates were similar with Jet CPAP and Bubble CPAP.

The total artificial heart for biventricular heart failure and beyond.

PubMed

Kasirajan, Vigneshwar; Tang, Daniel G; Katlaps, Gundars J; Shah, Keyur B

2012-05-01

Treatment options for late-stage biventricular heart failure are limited but include medical therapy with intravenous inotropes, biventricular assist devices (Bi-VADs) and the total artificial heart (TAH). In this manuscript, we review the indications, surgical techniques and outcomes for the TAH. The TAH offers biventricular replacement, rather than 'assistance', as the device is placed orthotopically after excision of the entire ventricular myocardium and all four native valves. In contrast to patients with Bi-VADs, patients with the TAH have no postoperative inotrope requirements, arrhythmias or inflow/outflow cannulae-related complications. Additionally, patients participate in rehabilitation early after device placement and the development of a portable drive may facilitate hospital discharge in the USA. Furthermore, total heart replacement may be ideal for heart failure associated with unique anatomical and mechanical complications. The TAH is an effective therapeutic option for the treatment of patients dying of heart failure who may not be suitable candidates for left ventricular assist devices.

What Reliability Engineers Should Know about Space Radiation Effects

NASA Technical Reports Server (NTRS)

DiBari, Rebecca

2013-01-01

Space radiation in space systems present unique failure modes and considerations for reliability engineers. Radiation effects is not a one size fits all field. Threat conditions that must be addressed for a given mission depend on the mission orbital profile, the technologies of parts used in critical functions and on application considerations, such as supply voltages, temperature, duty cycle, and redundancy. In general, the threats that must be addressed are of two types-the cumulative degradation mechanisms of total ionizing dose (TID) and displacement damage (DD). and the prompt responses of components to ionizing particles (protons and heavy ions) falling under the heading of single-event effects. Generally degradation mechanisms behave like wear-out mechanisms on any active components in a system: Total Ionizing Dose (TID) and Displacement Damage: (1) TID affects all active devices over time. Devices can fail either because of parametric shifts that prevent the device from fulfilling its application or due to device failures where the device stops functioning altogether. Since this failure mode varies from part to part and lot to lot, lot qualification testing with sufficient statistics is vital. Displacement damage failures are caused by the displacement of semiconductor atoms from their lattice positions. As with TID, failures can be either parametric or catastrophic, although parametric degradation is more common for displacement damage. Lot testing is critical not just to assure proper device fi.mctionality throughout the mission. It can also suggest remediation strategies when a device fails. This paper will look at these effects on a variety of devices in a variety of applications. This paper will look at these effects on a variety of devices in a variety of applications. (2) On the NEAR mission a functional failure was traced to a PIN diode failure caused by TID induced high leakage currents. NEAR was able to recover from the failure by reversing the current of a nearby Thermal Electric Cooler (turning the TEC into a heater). The elevated temperature caused the PIN diode to anneal and the device to recover. It was by lot qualification testing that NEAR knew the diode would recover when annealed. This paper will look at these effects on a variety of devices in a variety of applications. Single Event Effects (SEE): (1) In contrast to TID and displacement damage, Single Event Effects (SEE) resemble random failures. SEE modes can range from changes in device logic (single-event upset, or SEU). temporary disturbances (single-event transient) to catastrophic effects such as the destructive SEE modes, single-event latchup (SEL). single-event gate rupture (SEGR) and single-event burnout (SEB) (2) The consequences of nondestructive SEE modes such as SEU and SET depend critically on their application--and may range from trivial nuisance errors to catastrophic loss of mission. It is critical not just to ensure that potentially susceptible devices are well characterized for their susceptibility, but also to work with design engineers to understand the implications of each error mode. -For destructive SEE, the predominant risk mitigation strategy is to avoid susceptible parts, or if that is not possible. to avoid conditions under which the part may be susceptible. Destructive SEE mechanisms are often not well understood, and testing is slow and expensive, making rate prediction very challenging. (3) Because the consequences of radiation failure and degradation modes depend so critically on the application as well as the component technology, it is essential that radiation, component. design and system engineers work togetherpreferably starting early in the program to ensure critical applications are addressed in time to optimize the probability of mission success.

Long-term reliability study and failure analysis of quantum cascade lasers

NASA Astrophysics Data System (ADS)

Xie, Feng; Nguyen, Hong-Ky; Leblanc, Herve; Hughes, Larry; Wang, Jie; Miller, Dean J.; Lascola, Kevin

2017-02-01

Here we present lifetime test results of 4 groups of quantum cascade lasers (QCL) under various aging conditions including an accelerated life test. The total accumulated life time exceeds 1.5 million device·hours, which is the largest QCL reliability study ever reported. The longest single device aging time was 46.5 thousand hours (without failure) in the room temperature test. Four failures were found in a group of 19 devices subjected to the accelerated life test with a heat-sink temperature of 60 °C and a continuous-wave current of 1 A. Visual inspection of the laser facets of failed devices revealed an astonishing phenomenon, which has never been reported before, which manifested as a dark belt of an unknown substance appearing on facets. Although initially assumed to be contamination from the environment, failure analysis revealed that the dark substance is a thermally induced oxide of InP in the buried heterostructure semiinsulating layer. When the oxidized material starts to cover the core and blocks the light emission, it begins to cause the failure of QCLs in the accelerated test. An activation energy of 1.2 eV is derived from the dependence of the failure rate on laser core temperature. With the activation energy, the mean time to failure of the quantum cascade lasers operating at a current density of 5 kA/cm2 and heat-sink temperature of 25°C is expected to be 809 thousand hours.

A practical review for cardiac rehabilitation professionals of continuous-flow left ventricular assist devices: historical and current perspectives.

PubMed

Compostella, Leonida; Russo, Nicola; Setzu, Tiziana; Bottio, Tomaso; Compostella, Caterina; Tarzia, Vincenzo; Livi, Ugolino; Gerosa, Gino; Iliceto, Sabino; Bellotto, Fabio

2015-01-01

An increasing number of patients with end-stage heart failure are being treated with continuous-flow left ventricular assist devices (cf-LVADs). These patients provide new challenges to the staff in exercise-based cardiac rehabilitation (CR) programs. Even though experience remains limited, it seems that patients supported by cf-LVADs may safely engage in typical rehabilitative activities, provided that some attention is paid to specific aspects, such as the presence of a short external drive line. In spite of initial physical deconditioning, CR allows progressive improvement of symptoms such as fatigue and dyspnea. Intensity of rehabilitative activities should ideally be based on measured aerobic capacity and increased appropriately over time. Regular, long-term exercise training results in improved physical fitness and survival rates. Appropriate adjustment of cf-LVAD settings, together with maintenance of adequate blood volume, provides maximal output, while avoiding suction effects. Ventricular arrhythmias, although not necessarily constituting an immediate life-threatening situation, deserve treatment as they could lead to an increased rate of hospitalization and poorer quality of life. Atrial fibrillation may worsen symptoms of right ventricular failure and reduce exercise tolerance. Blood pressure measurements are possible in cf-LVAD patients only using a Doppler technique, and a mean blood pressure ≤80 mmHg is considered "ideal." Some patients may present with orthostatic intolerance, related to autonomic dysfunction. While exercise training constitutes the basic rehabilitative tool, a comprehensive intervention that includes psychological and social support could better meet the complex needs of patients in which cf-LVAD may offer prolonged survival.

Cost-Effectiveness of Implantable Pulmonary Artery Pressure Monitoring in Chronic Heart Failure.

PubMed

Sandhu, Alexander T; Goldhaber-Fiebert, Jeremy D; Owens, Douglas K; Turakhia, Mintu P; Kaiser, Daniel W; Heidenreich, Paul A

2016-05-01

This study aimed to evaluate the cost-effectiveness of the CardioMEMS (CardioMEMS Heart Failure System, St Jude Medical Inc, Atlanta, Georgia) device in patients with chronic heart failure. The CardioMEMS device, an implantable pulmonary artery pressure monitor, was shown to reduce hospitalizations for heart failure and improve quality of life in the CHAMPION (CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients) trial. We developed a Markov model to determine the hospitalization, survival, quality of life, cost, and incremental cost-effectiveness ratio of CardioMEMS implantation compared with usual care among a CHAMPION trial cohort of patients with heart failure. We obtained event rates and utilities from published trial data; we used costs from literature estimates and Medicare reimbursement data. We performed subgroup analyses of preserved and reduced ejection fraction and an exploratory analysis in a lower-risk cohort on the basis of the CHARM (Candesartan in Heart failure: Reduction in Mortality and Morbidity) trials. CardioMEMS reduced lifetime hospitalizations (2.18 vs. 3.12), increased quality-adjusted life-years (QALYs) (2.74 vs. 2.46), and increased costs ($176,648 vs. $156,569), thus yielding a cost of $71,462 per QALY gained and $48,054 per life-year gained. The cost per QALY gained was $82,301 in patients with reduced ejection fraction and $47,768 in those with preserved ejection fraction. In the lower-risk CHARM cohort, the device would need to reduce hospitalizations for heart failure by 41% to cost <$100,000 per QALY gained. The cost-effectiveness was most sensitive to the device's durability. In populations similar to that of the CHAMPION trial, the CardioMEMS device is cost-effective if the trial effectiveness is sustained over long periods. Post-marketing surveillance data on durability will further clarify its value. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Advanced Data Acquisition Systems with Self-Healing Circuitry

NASA Technical Reports Server (NTRS)

Larson, William E.; Ihlefeld, Curtis M.; Medelius, Pedro J.; Delgado, H. (Technical Monitor)

2001-01-01

Kennedy Space Center's Spaceport Engineering & Technology Directorate has developed a data acquisition system that will help drive down the cost of ground launch operations. This system automates both the physical measurement set-up function as well as configuration management documentation. The key element of the system is a self-configuring, self-calibrating, signal-conditioning amplifier that automatically adapts to any sensor to which it is connected. This paper will describe the core technology behind this device and the automated data system in which it has been integrated. The paper will also describe the revolutionary enhancements that are planned for this innovative measurement technology. All measurement electronics devices contain circuitry that, if it fails or degrades, requires the unit to be replaced, adding to the cost of operations. Kennedy Space Center is now developing analog circuits that will be able to detect their own failure and dynamically reconfigure their circuitry to restore themselves to normal operation. This technology will have wide ranging application in all electronic devices used in space and ground systems.

Intraoperative Transesophageal Echocardiography and Right Ventricular Failure After Left Ventricular Assist Device Implantation.

PubMed

Silverton, Natalie A; Patel, Ravi; Zimmerman, Josh; Ma, Jianing; Stoddard, Greg; Selzman, Craig; Morrissey, Candice K

2018-02-15

To determine whether intraoperative measures of right ventricular (RV) function using transesophageal echocardiography are associated with subsequent RV failure after left ventricular assist device (LVAD) implantation. Retrospective, nonrandomized, observational study. Single tertiary-level, university-affiliated hospital. The study comprised 100 patients with systolic heart failure undergoing elective LVAD implantation. Transesophageal echocardiographic images before and after cardiopulmonary bypass were analyzed to quantify RV function using tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (S'), fractional area change (FAC), RV global longitudinal strain, and RV free wall strain. A chart review was performed to determine which patients subsequently developed RV failure (right ventricular assist device placement or prolonged inotrope requirement ≥14 days). Nineteen patients (19%) subsequently developed RV failure. Postbypass FAC was the only measure of RV function that distinguished between the RV failure and non-RV failure groups (21.2% v 26.5%; p = 0.04). The sensitivity, specificity, and area under the curve of an abnormal RV FAC (<35%) for RV failure after LVAD implantation were 84%, 20%, and 0.52, respectively. No other intraoperative measure of RV function was associated with subsequent RV failure. RV failure increased ventilator time, intensive care unit and hospital length of stay, and mortality. Intraoperative measures of RV function such as tricuspid annular plane systolic excursion, tricuspid annular systolic velocity, and RV strain were not associated with RV failure after LVAD implantation. Decreased postbypass FAC was significantly associated with RV failure but showed poor discrimination. Copyright © 2018 Elsevier Inc. All rights reserved.

Physics-based process modeling, reliability prediction, and design guidelines for flip-chip devices

NASA Astrophysics Data System (ADS)

Michaelides, Stylianos

Flip Chip on Board (FCOB) and Chip-Scale Packages (CSPs) are relatively new technologies that are being increasingly used in the electronic packaging industry. Compared to the more widely used face-up wirebonding and TAB technologies, flip-chips and most CSPs provide the shortest possible leads, lower inductance, higher frequency, better noise control, higher density, greater input/output (I/O), smaller device footprint and lower profile. However, due to the short history and due to the introduction of several new electronic materials, designs, and processing conditions, very limited work has been done to understand the role of material, geometry, and processing parameters on the reliability of flip-chip devices. Also, with the ever-increasing complexity of semiconductor packages and with the continued reduction in time to market, it is too costly to wait until the later stages of design and testing to discover that the reliability is not satisfactory. The objective of the research is to develop integrated process-reliability models that will take into consideration the mechanics of assembly processes to be able to determine the reliability of face-down devices under thermal cycling and long-term temperature dwelling. The models incorporate the time and temperature-dependent constitutive behavior of various materials in the assembly to be able to predict failure modes such as die cracking and solder cracking. In addition, the models account for process-induced defects and macro-micro features of the assembly. Creep-fatigue and continuum-damage mechanics models for the solder interconnects and fracture-mechanics models for the die have been used to determine the reliability of the devices. The results predicted by the models have been successfully validated against experimental data. The validated models have been used to develop qualification and test procedures for implantable medical devices. In addition, the research has helped develop innovative face-down devices without the underfill, based on the thorough understanding of the failure modes. Also, practical design guidelines for material, geometry and process parameters for reliable flip-chip devices have been developed.

Failure Detecting Method of Fault Current Limiter System with Rectifier

NASA Astrophysics Data System (ADS)

Tokuda, Noriaki; Matsubara, Yoshio; Asano, Masakuni; Ohkuma, Takeshi; Sato, Yoshibumi; Takahashi, Yoshihisa

A fault current limiter (FCL) is extensively needed to suppress fault current, particularly required for trunk power systems connecting high-voltage transmission lines, such as 500kV class power system which constitutes the nucleus of the electric power system. We proposed a new type FCL system (rectifier type FCL), consisting of solid-state diodes, DC reactor and bypass AC reactor, and demonstrated the excellent performances of this FCL by developing the small 6.6kV and 66kV model. It is important to detect the failure of power devices used in the rectifier under the normal operating condition, for keeping the excellent reliability of the power system. In this paper, we have proposed a new failure detecting method of power devices most suitable for the rectifier type FCL. This failure detecting system is simple and compact. We have adapted the proposed system to the 66kV prototype single-phase model and successfully demonstrated to detect the failure of power devices.

49 CFR 395.15 - Automatic on-board recording devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... information concerning on-board system sensor failures and identification of edited data. Such support systems... driving today; (iv) Total hours on duty for the 7 consecutive day period, including today; (v) Total hours...-driver operation; (7) The on-board recording device/system identifies sensor failures and edited data...

neutron-Induced Failures in semiconductor Devices

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

Wender, Stephen Arthur

2017-03-13

Single Event Effects are a very significant failure mode in modern semiconductor devices that may limit their reliability. Accelerated testing is important for semiconductor industry. Considerable more work is needed in this field to mitigate the problem. Mitigation of this problem will probably come from Physicists and Electrical Engineers working together

Dielectric Spectroscopic Detection of Early Failures in 3-D Integrated Circuits.

PubMed

Obeng, Yaw; Okoro, C A; Ahn, Jung-Joon; You, Lin; Kopanski, Joseph J

The commercial introduction of three dimensional integrated circuits (3D-ICs) has been hindered by reliability challenges, such as stress related failures, resistivity changes, and unexplained early failures. In this paper, we discuss a new RF-based metrology, based on dielectric spectroscopy, for detecting and characterizing electrically active defects in fully integrated 3D devices. These defects are traceable to the chemistry of the insolation dielectrics used in the through silicon via (TSV) construction. We show that these defects may be responsible for some of the unexplained early reliability failures observed in TSV enabled 3D devices.

"Plastic" solar cells: self-assembly of bulk heterojunction nanomaterials by spontaneous phase separation.

PubMed

Peet, Jeffrey; Heeger, Alan J; Bazan, Guillermo C

2009-11-17

As the global demand for low-cost renewable energy sources intensifies, interest in new routes for converting solar energy to electricity is rapidly increasing. Although photovoltaic cells have been commercially available for more than 50 years, only 0.1% of the total electricity generated in the United States comes directly from sunlight. The earliest commercial solar technology remains the basis for the most prevalent devices in current use, namely, highly-ordered crystalline, inorganic solar cells, commonly referred to as silicon cells. Another class of solar cells that has recently inspired significant academic and industrial excitement is the bulk heterojunction (BHJ) "plastic" solar cell. Research by a rapidly growing community of scientists across the globe is generating a steady stream of new insights into the fundamental physics, the materials design and synthesis, the film processing and morphology, and the device science and architecture of BHJ technology. Future progress in the fabrication of high-performance BHJ cells will depend on our ability to combine aspects of synthetic and physical chemistry, condensed matter physics, and materials science. In this Account, we use a combination of characterization tools to tie together recent advances in BHJ morphology characterization, device photophysics, and thin-film solution processing, illustrating how to identify the limiting factors in solar cell performance. We also highlight how new processing methods, which control both the BHJ phase separation and the internal order of the components, can be implemented to increase the power conversion efficiency (PCE). The failure of many innovative materials to achieve high performance in BHJ solar cell devices has been blamed on "poor morphology" without significant characterization of either the structure of the phase-separated morphology or the nature of the charge carrier recombination. We demonstrate how properly controlling the "nanomorphology", which is critically dependent on minute experimental details at every step, from synthesis to device construction, provides a clear path to >10% PCE BHJ cells, which can be fabricated at a fraction of the cost of conventional solar cells.

Failure Mechanisms for III-Nitride HEMT Devices

DTIC Science & Technology

2013-11-19

rf plasma-assisted molecular beam epitaxy on freestanding GaN substrates, J. Cryst. Growth 380, 14-17 (2013). ii) Conference presentations (Invited...1 eFinal Report – AOARD Grant FA-2386-11-1-4107 Failure Mechanisms for III-nitride HEMT devices 19 November 2013 Principal Investigators: Martha...aspects of III-nitride HEMT materials and devices. Energy-filtered imaging of unstressed and stressed Ni/Au-gated AlGaN/GaN HEMTs indicated that

Failure mechanism of THz GaAs photoconductive antenna

NASA Astrophysics Data System (ADS)

Qadri, Syed B.; Wu, Dong H.; Graber, Benjamin D.; Mahadik, Nadeemullah A.; Garzarella, Anthony

2012-07-01

We investigated the failure mechanism of THz GaAs photoconductive antenna using high resolution x-ray diffraction topography. From these studies, it was found that grain boundaries are formed during the high frequency device operation. This results in the segregation of gold at the boundaries causing electromigration of the metal between the gold micro-strips. This disrupts the photocurrents from being produced by femtosecond laser thus preventing terahertz beam generation from the photoconductive antennae leading to device failure.

Cryogenic Quenching Process for Electronic Part Screening

NASA Technical Reports Server (NTRS)

Sheldon, Douglas J.; Cressler, John

2011-01-01

The use of electronic parts at cryogenic temperatures (less than 100 C) for extreme environments is not well controlled or developed from a product quality and reliability point of view. This is in contrast to the very rigorous and well-documented procedures to qualify electronic parts for mission use in the 55 to 125 C temperature range. A similarly rigorous methodology for screening and evaluating electronic parts needs to be developed so that mission planners can expect the same level of high reliability performance for parts operated at cryogenic temperatures. A formal methodology for screening and qualifying electronic parts at cryogenic temperatures has been proposed. The methodology focuses on the base physics of failure of the devices at cryogenic temperatures. All electronic part reliability is based on the bathtub curve, high amounts of initial failures (infant mortals), a long period of normal use (random failures), and then an increasing number of failures (end of life). Unique to this is the development of custom screening procedures to eliminate early failures at cold temperatures. The ability to screen out defects will specifically impact reliability at cold temperatures. Cryogenic reliability is limited by electron trap creation in the oxide and defect sites at conductor interfaces. Non-uniform conduction processes due to process marginalities will be magnified at cryogenic temperatures. Carrier mobilities change by orders of magnitude at cryogenic temperatures, significantly enhancing the effects of electric field. Marginal contacts, impurities in oxides, and defects in conductor/conductor interfaces can all be magnified at low temperatures. The novelty is the use of an ultra-low temperature, short-duration quenching process for defect screening. The quenching process is designed to identify those defects that will precisely (and negatively) affect long-term, cryogenic part operation. This quenching process occurs at a temperature that is at least 25 C colder than the coldest expected operating temperature. This quenching process is the opposite of the standard burn-in procedure. Normal burn-in raises the temperature (and voltage) to activate quickly any possible manufacturing defects remaining in the device that were not already rejected at a functional test step. The proposed inverse burn-in or quenching process is custom-tailored to the electronic device being used. The doping profiles, materials, minimum dimensions, interfaces, and thermal expansion coefficients are all taken into account in determining the ramp rate, dwell time, and temperature.

Ventricular assist devices in pediatrics

PubMed Central

Fuchs, A; Netz, H

2001-01-01

The implantation of a mechanical circulatory device for end-stage ventricular failure is a possible therapeutic approach in adult and pediatric cardiac surgery and cardiology. The aim of this article is to present mechanical circulatory assist devices used in infants and children with special emphasis on extracorporeal membrane oxygenation, Berlin Heart assist device, centrifugal pump and Medos assist device. The success of long-term support with implantable ventricular assist devices in adults and children has led to their increasing use as a bridge to transplantation in patients with otherwise non-treatable left ventricular failure, by transforming a terminal phase heart condition into a treatable cardiopathy. Such therapy allows rehabilitation of patients before elective cardiac transplantation (by removing contraindications to transplantation mainly represented by organ impairment) or acting as a bridge to recovery of the native left ventricular function (depending on underlying cardiac disease). Treatment may also involve permanent device implantation when cardiac transplantation is contraindicated. Indications for the implantation of assisted circulation include all states of cardiac failure that are reversible within a variable period of time or that require heart transplantation. This article will address the current status of ventricular assist devices by examining historical aspects of its development, current technical issues and clinical features of pediatric ventricular assist devices, including indications and contraindications for support. PMID:22368605

Physics-Based Compact Model for CIGS and CdTe Solar Cells: From Voltage-Dependent Carrier Collection to Light-Enhanced Reverse Breakdown: Preprint

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

Sun, Xingshu; Alam, Muhammad Ashraful; Raguse, John

2015-10-15

In this paper, we develop a physics-based compact model for copper indium gallium diselenide (CIGS) and cadmium telluride (CdTe) heterojunction solar cells that attributes the failure of superposition to voltage-dependent carrier collection in the absorber layer, and interprets light-enhanced reverse breakdown as a consequence of tunneling-assisted Poole-Frenkel conduction. The temperature dependence of the model is validated against both simulation and experimental data for the entire range of bias conditions. The model can be used to characterize device parameters, optimize new designs, and most importantly, predict performance and reliability of solar panels including the effects of self-heating and reverse breakdown duemore » to partial-shading degradation.« less

Evolution from electrophysiologic to hemodynamic monitoring: the story of left atrial and pulmonary artery pressure monitors.

PubMed

Mooney, Deirdre M; Fung, Erik; Doshi, Rahul N; Shavelle, David M

2015-01-01

Heart failure (HF) is a costly, challenging and highly prevalent medical condition. Hospitalization for acute decompensation is associated with high morbidity and mortality. Despite application of evidence-based medical therapies and technologies, HF remains a formidable challenge for virtually all healthcare systems. Repeat hospitalizations for acute decompensated HF (ADHF) can have major financial impact on institutions and resources. Early and accurate identification of impending ADHF is of paramount importance yet there is limited high quality evidence or infrastructure to guide management in the outpatient setting. Historically, ADHF was identified by physical exam findings or invasive hemodynamic monitoring during a hospital admission; however, advances in medical microelectronics and the advent of device-based diagnostics have enabled long-term ambulatory monitoring of HF patients in the outpatient setting. These monitors have evolved from piggybacking on cardiac implantable electrophysiologic devices to standalone implantable hemodynamic monitors that transduce left atrial or pulmonary artery pressures as surrogate measures of left ventricular filling pressure. As technology evolves, devices will likely continue to miniaturize while their capabilities grow. An important, persistent challenge that remains is developing systems to translate the large volumes of real-time data, particularly data trends, into actionable information that leads to appropriate, safe and timely interventions without overwhelming outpatient cardiology and general medical practices. Future directions for implantable hemodynamic monitors beyond their utility in heart failure may include management of other major chronic diseases such as pulmonary hypertension, end stage renal disease and portal hypertension.

Failure Mode Classification for Life Prediction Modeling of Solid-State Lighting

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

Sakalaukus, Peter Joseph

2015-08-01

Since the passing of the Energy Independence and Security Act of 2007, the U.S. government has mandated greater energy independence which has acted as a catalyst for accelerating and facilitating research efforts toward the development and deployment of market-driven solutions for energy-saving homes, buildings and manufacturing, as well as sustainable transportation and renewable electricity generation. As part of this effort, an emphasis toward advancing solid-state lighting technology through research, development, demonstration, and commercial applications is assisting in the phase out of the common incandescent light bulb, as well as developing a more economical lighting source that is less toxic thanmore » compact fluorescent lighting. This has led lighting manufacturers to pursue SSL technologies for a wide range of consumer lighting applications. An SSL luminaire’s lifetime can be characterized in terms of lumen maintenance life. Lumen maintenance or lumen depreciation is the percentage decrease in the relative luminous flux from that of the original, pristine luminous flux value. Lumen maintenance life is the estimated operating time, in hours, when the desired failure threshold is projected to be reached at normal operating conditions. One accepted failure threshold of SSL luminaires is lumen maintenance of 70% -- a 30% reduction in the light output of the luminaire. Currently, the only approved lighting standard that puts forth a recommendation for long-term luminous flux maintenance projections towards a specified failure threshold of an SSL luminaire is the IES TM-28-14 (TM28) standard. iii TM28 was derived as a means to compare luminaires that have been tested at different facilities, research labs or companies. TM28 recommends the use of the Arrhenius equation to determine SSL device specific reaction rates from thermally driven failure mechanisms used to characterize a single failure mode – the relative change in the luminous flux output or “light power” of the SSL luminaire. The use of the Arrhenius equation necessitates two different temperature conditions, 25°C and 45°C are suggested by TM28, to determine the SSL lamp specific activation energy. One principal issue with TM28 is the lack of additional stresses or parameters needed to characterize non-temperature dependent failure mechanisms. Another principal issue with TM28 is the assumption that lumen maintenance or lumen depreciation gives an adequate comparison between SSL luminaires. Additionally, TM28 has no process for the determination of acceleration factors or lifetime estimations. Currently, a literature gap exists for established accelerated test methods for SSL devices to assess quality, reliability and durability before being introduced into the marketplace. Furthermore, there is a need for Physics-of-Failure based approaches to understand the processes and mechanisms that induce failure for the assessment of SSL reliability in order to develop generalized acceleration factors that better represent SSL product lifetime. This and the deficiencies in TM28 validate the need behind the development of acceleration techniques to quantify SSL reliability under a variety of environmental conditions. The ability to assess damage accrual and investigate reliability of SSL components and systems is essential to understanding the life time of the SSL device itself. The methodologies developed in this work increases the understanding of SSL devices iv through the investigation of component and device reliability under a variety of accelerated test conditions. The approaches for suitable lifetime predictions through the development of novel generalized acceleration factors, as well as a prognostics and health management framework, will greatly reduce the time and effort needed to produce SSL acceleration factors for the development of lifetime predictions.« less

Endovascular stent-graft repair of failed endovascular abdominal aortic aneurysm repair.

PubMed

Baril, Donald T; Silverberg, Daniel; Ellozy, Sharif H; Carroccio, Alfio; Jacobs, Tikva S; Sachdev, Ulka; Teodorescu, Victoria J; Lookstein, Robert A; Marin, Michael L

2008-01-01

Despite high initial technical success, the long-term durability of endovascular abdominal aortic aneurysm repair (EVAR) continues to be a concern. Following EVAR, patients can experience endoleaks, device migration, device fractures, or aneurysm growth that may require intervention. The purpose of this study was to review all patients treated with secondary endovascular devices at our institution for failed EVAR procedures. Over an 8-year period, 988 patients underwent EVAR, of whom 42 (4.3%) required secondary interventions involving placement of additional endovascular devices. Data regarding patient characteristics, aneurysm size, initial device type, time until failure, failure etiology, secondary interventions, and outcomes were reviewed. The mean time from initial operation until second operation was 34.1 months. Failures included type I endoleaks in 38 patients (90.5%), type III endoleaks in two patients (4.8%), and enlarging aneurysms without definite endoleaks in two patients (4.8%). The overall technical success rate for secondary repair was 92.9% (39/42). Perioperative complications occurred in nine patients (21.4%), including wound complications (n = 6), cerebrovascular accident (CVA) (n = 1), foot drop (n = 1), and death (n = 1). Mean follow-up following secondary repair was 16.4 months (range 1-50). Eighty-six percent of patients treated with aortouni-iliac devices had successful repairs compared to 45% of patients treated with proximal cuffs. Ten patients (23.8%) had persistent or recurrent type I or type III endoleaks following revision. Of these, four had tertiary interventions, including two patients who had additional devices placed. Failures following EVAR occur in a small but significant number of patients. When anatomically possible, endovascular revision offers a safe means of treating these failures. Aortouni-iliac devices appear to offer a more durable repair than the proximal cuff for treatment of proximal type I endoleaks. Midterm results indicate that these patients may require additional procedures but have a low rate of aneurysm-related mortality. Longer-term follow-up is necessary to determine the durability of these endovascular revisions.

Predicted reliability of aerospace electronics: Application of two advanced probabilistic concepts

NASA Astrophysics Data System (ADS)

Suhir, E.

Two advanced probabilistic design-for-reliability (PDfR) concepts are addressed and discussed in application to the prediction, quantification and assurance of the aerospace electronics reliability: 1) Boltzmann-Arrhenius-Zhurkov (BAZ) model, which is an extension of the currently widely used Arrhenius model and, in combination with the exponential law of reliability, enables one to obtain a simple, easy-to-use and physically meaningful formula for the evaluation of the probability of failure (PoF) of a material or a device after the given time in operation at the given temperature and under the given stress (not necessarily mechanical), and 2) Extreme Value Distribution (EVD) technique that can be used to assess the number of repetitive loadings that result in the material/device degradation and eventually lead to its failure by closing, in a step-wise fashion, the gap between the bearing capacity (stress-free activation energy) of the material or the device and the demand (loading). It is shown that the material degradation (aging, damage accumulation, flaw propagation, etc.) can be viewed, when BAZ model is considered, as a Markovian process, and that the BAZ model can be obtained as the ultimate steady-state solution to the well-known Fokker-Planck equation in the theory of Markovian processes. It is shown also that the BAZ model addresses the worst, but a reasonably conservative, situation. It is suggested therefore that the transient period preceding the condition addressed by the steady-state BAZ model need not be accounted for in engineering evaluations. However, when there is an interest in understanding the transient degradation process, the obtained solution to the Fokker-Planck equation can be used for this purpose. As to the EVD concept, it attributes the degradation process to the accumulation of damages caused by a train of repetitive high-level loadings, while loadings of levels that are considerably lower than their extreme values do not contribute- appreciably to the finite lifetime of a material or a device. In our probabilistic risk management (PRM) based analysis we treat the stress-free activation energy (capacity) as a normally distributed random variable, and choose, for the sake of simplicity, the (single-parametric) Rayleigh law as the basic distribution underlying the EVD. The general concepts addressed and discussed are illustrated by numerical examples. It is concluded that the application of the PDfR approach and particularly the above two advanced models should be considered as a natural, physically meaningful, informative, comprehensive, and insightful technique that reflects well the physics underlying the degradation processes in materials, devices and systems. It is the author's belief that they will be widely used in engineering practice, when high reliability is imperative, and the ability to quantify it is highly desirable.

Device Longevity in a Contemporary Cohort of ICD/CRT-D Patients Undergoing Device Replacement.

PubMed

Zanon, Francesco; Martignani, Cristian; Ammendola, Ernesto; Menardi, Endrj; Narducci, Maria Lucia; DE Filippo, Paolo; Santamaria, Matteo; Campana, Andrea; Stabile, Giuseppe; Potenza, Domenico Rosario; Pastore, Gianni; Iori, Matteo; LA Rosa, Concetto; Biffi, Mauro

2016-07-01

The longevity of defibrillators (ICD) is extremely important from both a clinical and economic perspective. We studied the reasons for device replacement, the longevity of removed ICD, and the existence of possible factors associated with shorter service life. Consecutive patients who underwent ICD replacement from March 2013 to May 2015 in 36 Italian centers were included in this analysis. Data on replaced devices were collected. A total of 953 patients were included in this analysis. In 813 (85%) patients the reason for replacement was battery depletion, while 88 (9%) devices were removed for clinical reasons and the remaining 52 because of system failure (i.e., lead or ICD generator failure or a safety advisory indication). The median service life was 5.9 years (25th-75th percentile, 4.9-6.9) for single- and dual-chamber ICD and 4.9 years (25th-75th percentile, 4.0-5.7) for CRT-D. On multivariate analysis, the factors CRT-D device, SC/DC ICD generator from Biotronik, percentage of ventricular pacing, and the occurrence of a system failure were positively associated with a replacement procedure. By contrast, the device from Boston Scientific was an independent protective factor against replacement. Considerable differences were seen in battery duration in both ICD and CRT-D. Specifically, Biotronik devices showed the shortest longevity among ICD and Boston Scientific showed the longest longevity among CRT-D (log-rank test, P < 0.001 for pairwise comparisons). Several factors were associated with shorter service life of ICD devices: CRT-D, occurrence of system failure and percentage of ventricular pacing. Our results confirmed significant differences among manufacturers. © The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals, Inc.

Device monitoring strategies in acute heart failure syndromes.

PubMed

Samara, Michael A; Tang, W H Wilson

2011-09-01

Acute heart failure syndromes (AHFS) represent the most common discharge diagnoses in adults over age 65 and translate into dramatically increased heart failure-associated morbidity and mortality. Conventional approaches to the early detection of pulmonary and systemic congestion have been shown to be of limited sensitivity. Despite their proven efficacy, disease management and structured telephone support programs have failed to achieve widespread use in part due to their resource intensiveness and reliance upon motivated patients. While once thought to hold great promise, results from recent prospective studies on telemonitoring strategies have proven disappointing. Implantable devices with their capacity to monitor electrophysiologic and hemodynamic parameters over long periods of time and with minimal reliance on patient participation may provide solutions to some of these problems. Conventional electrophysiologic parameters and intrathoracic impedance data are currently available in the growing population of heart failure patients with equipped devices. A variety of implantable hemodynamic monitors are currently under investigation. How best to integrate these devices into a systematic approach to the management of patients before, during, and after AHFS is yet to be established.

Self-administration of medicine and older people.

PubMed

McGraw, C; Drennan, V

Non-adherence to medication regimens is a significant problem in older patients, which can lead to therapeutic failure and the wastage of resources. Common causes include poor patient memory, physical difficulties, unpleasant side effects and a lack of social support. Strategies such as careful labelling, self-administration of medicine programmes, simplifying drug regimens and the use of medication compliance devices can help to promote patient adherence. Some of these interventions will work for certain patients, however the authors recommend that a multidisciplinary assessment and a regular review of each patient's ability to adhere to medication should be undertaken.

Fear of failure and self-handicapping in college physical education.

PubMed

Chen, Lung Hung; Chen, Mei-Yen; Lin, Meng-Shyan; Kee, Ying Hwa; Shui, Shang-Hsueh

2009-12-01

The purpose of this study was to examine the relationship between fear of failure and self-handicapping within the context of physical education. Participants were 103 college freshmen enrolled in aerobic dance physical education classes in Taiwan. They completed the Performance Failure Appraisal Inventory and Self-Handicapping Scale for Sport 3 mo. after entering the class. Hierarchical regression indicated that scores on fear of failure predicted self-handicapping scores.

Right Ventricular Failure Post LVAD Implantation Corrected with Biventricular Support: An In Vitro Model.

PubMed

Shehab, Sajad; Allida, Sabine M; Davidson, Patricia M; Newton, Phillip J; Robson, Desiree; Jansz, Paul C; Hayward, Christopher S

Right ventricular failure after left ventricular assist device (LVAD) implantation is associated with high mortality. Management remains limited to pharmacologic therapy and temporary mechanical support. Delayed right ventricular assist device (RVAD) support after LVAD implantation is associated with poorer outcomes. With the advent of miniaturized, durable, continuous flow ventricular assist device systems, chronic RVAD and biventricular assist device (BiVAD) support has been used with some success. The purpose of this study was to assess combined BiVAD and LVAD with delayed RVAD support within a four-elemental mock circulatory loop (MCL) simulating the human cardiovascular system. Our hypothesis was that delayed continuous flow RVAD (RVAD) would produce similar hemodynamic and flow parameters to those of initial BiVAD support. Using the MCL, baseline biventricular heart failure with elevated right and left filling pressures with low cardiac output was simulated. The addition of LVAD within a biventricular configuration improved cardiac output somewhat, but was associated with persistent right heart failure with elevated right-sided filling pressures. The addition of an RVAD significantly improved LVAD outputs and returned filling pressures to normal throughout the circulation. In conclusion, RVAD support successfully restored hemodynamics and flow parameters of biventricular failure supported with isolated LVAD with persistent elevated right atrial pressure.

First permanent implant of the Jarvik 2000 Heart.

PubMed

Westaby, S; Banning, A P; Jarvik, R; Frazier, O H; Pigott, D W; Jin, X Y; Catarino, P A; Saito, S; Robson, D; Freeland, A; Myers, T J; Poole-Wilson, P A

2000-09-09

Heart failure is a major public-health concern. Quality and duration of life on maximum medical therapy are poor. The availability of donor hearts is severely limited, therefore an alternative approach is necessary. We have explored the use of a new type of left-ventricular assist device intended as a long-term solution to end-stage heart failure. As part of a prospective clinical trial, we implanted the first permanent Jarvik 2000 Heart--an intraventricular device with an innovative power delivery system--into a 61-year-old man (New York Heart Association functional class IV) with dilated cardiomyopathy. We assessed the effect of this left-ventricular assist device on both native heart function and the symptoms and systemic characteristics of heart failure. The Jarvik 2000 Heart sustained the patient's circulation, and was practical and user-friendly. After 6 weeks, exercise tolerance, myocardial function, and end-organ function improved. Symptoms of heart failure have resolved, and continuous decreased pulse-pressure perfusion has had no adverse effects in the short term. There has been no significant haemolysis and no device-related complications. The skull-mounted pedestal is unobtrusive and has healed well. The initial success of this procedure raises the possibility of a new treatment for end-stage heart failure. In the longer term, its role will be determined by mechanical reliability.

Recent advances in heart failure.

PubMed

Kassi, Mahwash; Hannawi, Bashar; Trachtenberg, Barry

2018-03-01

Acute heart failure continues to be a challenge as there is limited benefit of numerous agents that have been tested. Cardiac resynchronization therapy remains standard of care, yet timing and need for implantable cardiac defibrillator has been brought into question with the recent randomized trials. Several recent advances have been made towards management of heart failure both in drug and device therapy. The purpose of this review is to provide an update on the most important recent studies on heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Two new drugs have been added to the armamentarium for HFrEF; ivabradine and angiotensin receptor-neprilysin inhibitors (ARNIs). Initial data from a new left ventricular assist device (LVAD) pump, the HeartMate 3 (HM III), have demonstrated no reports of pump thrombosis at 6 months, but stroke and right ventricle failure continue to be a challenge with comparable rates compared with the HeartMate II. Several large studies in HFpEF failed to show improvement in outcomes and management continues to be geared towards lifestyle modification and symptom relief. Newer therapies and devices have met with great success, yet there are several therapies that provide no benefit and even harm. A careful review of the recent literature remains instrumental to the effective management of patients with heart failure.

The fundamentals of extra-corporeal membrane oxygenation.

PubMed

Aghili, N; Kang, S; Kapur, N K

2015-02-01

During the past 50 years, pharmacologic advancements for cardiovascular risk factors and device innovation for the management of coronary disease, including acute myocardial infarction have radically changed the landscape of heart disease. At present, nearly 25% of individuals develop chronic heart failure after an acute myocardial infarction. It is estimated that nearly 2.6% of the American population suffers from heart failure. In the modern era, miniaturized continuous flow ventricular assist devices are now demonstrating nearly 75% 2-year survival rates with improved patient functionality. As a result, elderly patients with cardiogenic shock for whom medical treatment held minimal promise, may now be viable candidates for advanced mechanical therapies. Given this option, there is a need for more approaches to salvage patients from cardiogenic shock with percutaneously delivered mechanical circulatory support (pMCS) systems. The use of pMCS is growing and now includes patients with acute and chronic heart failure as well as patients undergoing high risk interventional and electrophysiology procedures. Each of these devices has a unique hemodynamic effect and therefore an in-depth understanding of device characteristics is required for optimal patient management. Extracorporeal membrane oxygenation (ECMO) is one of the earliest types of pMCS systems primarily used for cardiorespiratory failure. ECMO can be used in different configurations, which makes it a versatile hemodynamic support device for different patient scenarios. In this paper, the authors review different configurations, indications, and hemodynamic profile of ECMO in respiratory and cardiac failure patients.

New therapy, new challenges: The effects of long-term continuous flow left ventricular assist device on inflammation.

PubMed

Grosman-Rimon, Liza; Billia, Filio; Fuks, Avi; Jacobs, Ira; A McDonald, Michael; Cherney, David Z; Rao, Vivek

2016-07-15

Surgically implanted continuous flow left ventricular assist devices (CF-LVADs) are currently used in patients with end-stage heart failure (HF). However, CF-LVAD therapy introduces a new set of complications and adverse events in these patients. Major adverse events with the CF-LVAD include right heart failure, vascular dysfunction, stroke, hepatic failure, and multi-organ failure, complications that may have inflammation as a common etiology. Our aim was to review the current evidence showing a relationship between these adverse events and elevated levels of inflammatory biomarkers in CF-LVAD recipients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Understanding the C-pulse device and its potential to treat heart failure.

PubMed

Sales, Virna L; McCarthy, Patrick M

2010-03-01

The Sunshine Heart C-Pulse (C-Pulse; Sunshine Heart Inc., Tustin, CA) device is an extra-aortic implantable counterpulsation pump designed as a non-blood contacting ambulatory heart assist device, which may provide relief from symptoms for class II-III congestive heart failure patients. It has a comparable hemodynamic augmentation to intra-aortic balloon counterpulsation devices. The C-Pulse cuff is implanted through a median sternotomy, secured around the ascending aorta, and pneumatically driven by an external system controller. Pre-clinical studies in the acute pig model, and initial temporary clinical studies in patients undergoing off-pump coronary bypass surgery have shown substantial increase in diastolic perfusion of the coronary vessels, which translated to a favorable improvement in ventricular function. A U.S. prospective multi-center trial to evaluate the safety and efficacy of the C-Pulse in class III patients with moderate heart failure is now in progress.

Transcranial Doppler quantification of residual shunt after percutaneous patent foramen ovale closure: correlation of device efficacy with intracardiac anatomic measures.

PubMed

Sorensen, Sherman G; Spruance, Spotswood L; Smout, Randall; Horn, Susan

2012-06-01

Percutaneous, mechanical closure of defects of the atrial septum fails to completely resolve shunting in up to 20% of cases. Little is known about the factors associated with device failure. We measured the left atrial opening (X), right atrial opening (Z), tunnel length (Y), septum secundum, device-septum primum separation, and tunnel compressibility of the patent foramen ovale (PFO) in 301 patients with cryptogenic neurological events, PFO anatomy, and severe Valsalva shunting (Spencer Grade 5-5+). All patients then underwent percutaneous closure with the GORE®HELEX Septal Occluder device and were evaluated at 3 months for residual shunt by transcranial Doppler (TCD). Severe residual Valsalva shunt (TCD Grade 5-5+) was found at 3 months in 21 of 301 (7%) patients. X, Y, and Z were associated with failure with a high degree of statistical significance, whereas the width of the septum secundum, device-septum primum separation, and tunnel compressibility were not. An unanticipated finding was that 14 of 35 (40%) patients sized with a large balloon failed compared with 9 of 280 (3%) sized with a small balloon (P < 0.0001). In the multivariate logistic regression model, X (P = < 0.0001) and balloon size (P < 0.0001) were both strong predictors of failure. In an intracardiac echocardiography-defined PFO population, characterized by severe baseline Valsalva shunt and a high incidence of persistent (rest) shunting, association of six intracardiac measurements to closure device failure by multivariate logistic regression showed that the width of the left atrial opening was a strong predictor of residual shunting. An unanticipated finding was that use of a large sizing balloon was also strongly associated with failure. ©2012, Wiley Periodicals, Inc.

10 CFR 71.45 - Lifting and tie-down standards for all packages.

Code of Federal Regulations, 2011 CFR

2011-01-01

... that failure of any lifting device under excessive load would not impair the ability of the package to... its yield strength, a static force applied to the center of gravity of the package having a vertical... package must be designed so that failure of the device under excessive load would not impair the ability...

10 CFR 71.45 - Lifting and tie-down standards for all packages.

Code of Federal Regulations, 2014 CFR

2014-01-01

... that failure of any lifting device under excessive load would not impair the ability of the package to... its yield strength, a static force applied to the center of gravity of the package having a vertical... package must be designed so that failure of the device under excessive load would not impair the ability...

10 CFR 71.45 - Lifting and tie-down standards for all packages.

Code of Federal Regulations, 2012 CFR

2012-01-01

... that failure of any lifting device under excessive load would not impair the ability of the package to... its yield strength, a static force applied to the center of gravity of the package having a vertical... package must be designed so that failure of the device under excessive load would not impair the ability...

10 CFR 71.45 - Lifting and tie-down standards for all packages.

Code of Federal Regulations, 2013 CFR

2013-01-01

... that failure of any lifting device under excessive load would not impair the ability of the package to... its yield strength, a static force applied to the center of gravity of the package having a vertical... package must be designed so that failure of the device under excessive load would not impair the ability...

10 CFR 71.45 - Lifting and tie-down standards for all packages.

Code of Federal Regulations, 2010 CFR

2010-01-01

... that failure of any lifting device under excessive load would not impair the ability of the package to... its yield strength, a static force applied to the center of gravity of the package having a vertical... package must be designed so that failure of the device under excessive load would not impair the ability...

14 CFR 29.687 - Spring devices.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 27.687 - Spring devices.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

Biomechanical Comparison of Parallel and Crossed Suture Repair for Longitudinal Meniscus Tears.

PubMed

Milchteim, Charles; Branch, Eric A; Maughon, Ty; Hughey, Jay; Anz, Adam W

2016-04-01

Longitudinal meniscus tears are commonly encountered in clinical practice. Meniscus repair devices have been previously tested and presented; however, prior studies have not evaluated repair construct designs head to head. This study compared a new-generation meniscus repair device, SpeedCinch, with a similar established device, Fast-Fix 360, and a parallel repair construct to a crossed construct. Both devices utilize self-adjusting No. 2-0 ultra-high molecular weight polyethylene (UHMWPE) and 2 polyether ether ketone (PEEK) anchors. Crossed suture repair constructs have higher failure loads and stiffness compared with simple parallel constructs. The newer repair device would exhibit similar performance to an established device. Controlled laboratory study. Sutures were placed in an open fashion into the body and posterior horn regions of the medial and lateral menisci in 16 cadaveric knees. Evaluation of 2 repair devices and 2 repair constructs created 4 groups: 2 parallel vertical sutures created with the Fast-Fix 360 (2PFF), 2 crossed vertical sutures created with the Fast-Fix 360 (2XFF), 2 parallel vertical sutures created with the SpeedCinch (2PSC), and 2 crossed vertical sutures created with the SpeedCinch (2XSC). After open placement of the repair construct, each meniscus was explanted and tested to failure on a uniaxial material testing machine. All data were checked for normality of distribution, and 1-way analysis of variance by ranks was chosen to evaluate for statistical significance of maximum failure load and stiffness between groups. Statistical significance was defined as P < .05. The mean maximum failure loads ± 95% CI (range) were 89.6 ± 16.3 N (125.7-47.8 N) (2PFF), 72.1 ± 11.7 N (103.4-47.6 N) (2XFF), 71.9 ± 15.5 N (109.4-41.3 N) (2PSC), and 79.5 ± 25.4 N (119.1-30.9 N) (2XSC). Interconstruct comparison revealed no statistical difference between all 4 constructs regarding maximum failure loads (P = .49). Stiffness values were also similar, with no statistical difference on comparison (P = .28). Both devices in the current study had similar failure load and stiffness when 2 vertical or 2 crossed sutures were tested in cadaveric human menisci. Simple parallel vertical sutures perform similarly to crossed suture patterns at the time of implantation.

Practice of Regulatory Science (Development of Medical Devices).

PubMed

Niimi, Shingo

2017-01-01

Prototypes of medical devices are made in accordance with the needs of clinical practice, and for systems required during the initial process of medical device development for new surgical practices. Verification of whether these prototypes produce the intended performance specifications is conducted using basic tests such as mechanical and animal tests. The prototypes are then improved and modified until satisfactory results are obtained. After a prototype passes through a clinical trial process similar to that for new drugs, application for approval is made. In the approval application process, medical devices are divided into new, improved, and generic types. Reviewers judge the validity of intended use, indications, operation procedures, and precautions, and in addition evaluate the balance between risk and benefit in terms of efficacy and safety. Other characteristics of medical devices are the need for the user to attain proficiency in usage techniques to ensure efficacy and safety, and the existence of a variety of medical devices for which assessment strategies differ, including differences in impact on the body in cases in which a physical burden to the body or failure of a medical device develops. Regulatory science of medical devices involves prediction, judgment, and evaluation of efficacy, safety, and quality, from which data result which can become indices in the development stages from design to application for approval. A reduction in the number of animals used for testing, improvement in efficiency, reduction of the necessity for clinical trials, etc. are expected through rational setting of evaluation items.

Remote monitoring of cardiovascular implanted electronic devices: a paradigm shift for the 21st century.

PubMed

Cronin, Edmond M; Varma, Niraj

2012-07-01

Traditional follow-up of cardiac implantable electronic devices involves the intermittent download of largely nonactionable data. Remote monitoring represents a paradigm shift from episodic office-based follow-up to continuous monitoring of device performance and patient and disease state. This lessens device clinical burden and may also lead to cost savings, although data on economic impact are only beginning to emerge. Remote monitoring technology has the potential to improve the outcomes through earlier detection of arrhythmias and compromised device integrity, and possibly predict heart failure hospitalizations through integration of heart failure diagnostics and hemodynamic monitors. Remote monitoring platforms are also huge databases of patients and devices, offering unprecedented opportunities to investigate real-world outcomes. Here, the current status of the field is described and future directions are predicted.

Tailoring therapy for ischemic cardiomyopathy: is Laplace's law enough?

PubMed

Adhyapak, Srilakshmi M; Parachuri, V Rao

2017-09-01

The burden of heart failure has long plagued the productive years of the population, with therapeutic advances in the timely treatment of ischemic heart disease decreasing its associated mortality. Angiotensin-converting enzyme inhibitors and β-blockers have impacted heart failure therapeutics in a revolutionary way. The importance of blockade of the renin-angiotensin system and adrenergic stimulation are fully accepted concepts that apply in young and old, symptomatic and asymptomatic, borderline low and very low Ejection Fraction (EF), left ventricular failure and biventricular failure. Despite several interventions, both pharmaceutical and device based for the treatment of ensuing heart failure, the incidence is increasing in large proportions. Newer molecules like sacubitril show more promise. Despite these novel therapies, several patients relentlessly progress to a stage of advanced heart failure. The use of left-ventricular-assist devices has variable clinical benefit, with some patients progressing to heart transplantation.

Device for detecting imminent failure of high-dielectric stress capacitors. [Patent application

DOEpatents

McDuff, G.G.

1980-11-05

A device is described for detecting imminent failure of a high-dielectric stress capacitor utilizing circuitry for detecting pulse width variations and pulse magnitude variations. Inexpensive microprocessor circuitry is utilized to make numerical calculations of digital data supplied by detection circuitry for comparison of pulse width data and magnitude data to determine if preselected ranges have been exceeded, thereby indicating imminent failure of a capacitor. Detection circuitry may be incorporated in transmission lines, pulse power circuitry, including laser pulse circuitry or any circuitry where capacitors or capacitor banks are utilized.

Device for detecting imminent failure of high-dielectric stress capacitors

DOEpatents

McDuff, George G.

1982-01-01

A device for detecting imminent failure of a high-dielectric stress capacitor utilizing circuitry for detecting pulse width variations and pulse magnitude variations. Inexpensive microprocessor circuitry is utilized to make numerical calculations of digital data supplied by detection circuitry for comparison of pulse width data and magnitude data to determine if preselected ranges have been exceeded, thereby indicating imminent failure of a capacitor. Detection circuitry may be incorporated in transmission lines, pulse power circuitry, including laser pulse circuitry or any circuitry where capacitors or capactior banks are utilized.

Extracorporeal Respiratory Support With a Miniature Integrated Pediatric Pump-Lung Device in an Acute Ovine Respiratory Failure Model.

PubMed

Wei, Xufeng; Sanchez, Pablo G; Liu, Yang; Claire Watkins, A; Li, Tieluo; Griffith, Bartley P; Wu, Zhongjun J

2016-11-01

Respiratory failure is one of the major causes of mortality and morbidity all over the world. Therapeutic options to treat respiratory failure remain limited. The objective of this study was to evaluate the gas transfer performance of a newly developed miniature portable integrated pediatric pump-lung device (PediPL) with small membrane surface for respiratory support in an acute ovine respiratory failure model. The respiratory failure was created in six adult sheep using intravenous anesthesia and reduced mechanical ventilation at 2 breaths/min. The PediPL device was surgically implanted and evaluated for respiratory support in a venovenous configuration between the right atrium and pulmonary artery. The hemodynamics and respiratory status of the animals during support with the device gas transfer performance of the PediPL were studied for 4 h. The animals exhibited respiratory failure 30 min after mechanical ventilation was reduced to 2 breaths/min, indicated by low oxygen partial pressure, low oxygen saturation, and elevated carbon dioxide in arterial blood. The failure was reversed by establishing respiratory support with the PediPL after 30 min. The rates of O 2 transfer and CO 2 removal of the PediPL were 86.8 and 139.1 mL/min, respectively. The results demonstrated that the PediPL (miniature integrated pump-oxygenator) has the potential to provide respiratory support as a novel treatment for both hypoxia and hypercarbia. The compact size of the PediPL could allow portability and potentially be used in many emergency settings to rescue patients suffering acute lung injury. Copyright © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Degradation modeling of mid-power white-light LEDs by using Wiener process.

PubMed

Huang, Jianlin; Golubović, Dušan S; Koh, Sau; Yang, Daoguo; Li, Xiupeng; Fan, Xuejun; Zhang, G Q

2015-07-27

The IES standard TM-21-11 provides a guideline for lifetime prediction of LED devices. As it uses average normalized lumen maintenance data and performs non-linear regression for lifetime modeling, it cannot capture dynamic and random variation of the degradation process of LED devices. In addition, this method cannot capture the failure distribution, although it is much more relevant in reliability analysis. Furthermore, the TM-21-11 only considers lumen maintenance for lifetime prediction. Color shift, as another important performance characteristic of LED devices, may also render significant degradation during service life, even though the lumen maintenance has not reached the critical threshold. In this study, a modified Wiener process has been employed for the modeling of the degradation of LED devices. By using this method, dynamic and random variations, as well as the non-linear degradation behavior of LED devices, can be easily accounted for. With a mild assumption, the parameter estimation accuracy has been improved by including more information into the likelihood function while neglecting the dependency between the random variables. As a consequence, the mean time to failure (MTTF) has been obtained and shows comparable result with IES TM-21-11 predictions, indicating the feasibility of the proposed method. Finally, the cumulative failure distribution was presented corresponding to different combinations of lumen maintenance and color shift. The results demonstrate that a joint failure distribution of LED devices could be modeled by simply considering their lumen maintenance and color shift as two independent variables.

A worldwide experience of the management of battery failures and chronic device retrieval of the Nanostim leadless pacemaker.

PubMed

Lakkireddy, Dhanunjaya; Knops, Reinoud; Atwater, Brett; Neuzil, Petr; Ip, John; Gonzalez, Elkin; Friedman, Paul; Defaye, Pascal; Exner, Derek; Aonuma, Kazutaka; Doshi, Rahul; Sperzel, Johannes; Reddy, Vivek

2017-12-01

The Nanostim leadless pacemaker (LP) met the primary endpoints in an investigational device exemption trial, and was shown to be fully retrievable percutaneously. In October 2016, St Jude Medical issued a worldwide alert of a battery malfunction that caused lost pacing output and LP communication. To report the battery failure mechanism and incidence and the worldwide patient management, including device retrieval experiences. The affected LP battery is a custom lithium-carbon monofluoride cell. These were returned after failure and underwent analysis assessing electronics and battery performance. Data were collected in ongoing clinical studies when LPs were abandoned or retrieved. Of 1423 LPs implanted worldwide, there were 34 battery failures, occurring at 2.9 ± 0.4 years with no instances of associated patient injury. Analysis of returned batteries revealed an increase in battery resistance caused by insufficient electrolyte availability at the cathode/anode interface. A total of 66 of 73 retrieval attempts were successful (90.4%; implant duration range: 0.2-4.0 years). The LP docking button was inaccessible in 6 patients, and the docking button detached from the LP during retrieval in 1 patient. There was 1 case of arteriovenous fistula and another case of the LP docking button migrating into the pulmonary artery. There were also 115 non-LP retrieval patients after the advisory who received an additional pacemaker, with no adverse device-to-device interactions reported. As with standard pacers, LPs can have critical battery failures. Chronic retrieval of LPs is safe and efficacious. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Ventricular Assist Device and Destination Therapy Candidates from Preoperative Selection Through End of Hospitalization.

PubMed

Doty, Diane

2015-12-01

Mechanical circulatory support (MCS) devices offer advanced heart failure patients a potential long-term solution. MCS devices implantation is increasing related to the increased volume of heart failure patients, the shortfall of suitable donors, and the advanced technology and smaller size of the devices. To ensure a successful outcome, some key elements must be taken into consideration and managed: patient selection, preoperative preparation, intraoperative care, postoperative care, and posthospital education. The ultimate success of an MCS implantation relies on a multidisciplinary approach and excellent patient/caregiver education in each phase of hospitalization. Copyright © 2015 Elsevier Inc. All rights reserved.

Limitations of the Outback LTD re-entry device in femoropopliteal chronic total occlusions.

PubMed

Shin, Susanna H; Baril, Donald; Chaer, Rabih; Rhee, Robert; Makaroun, Michel; Marone, Luke

2011-05-01

Subintimal recanalization for the treatment of femoropopliteal chronic total occlusions (CTO) occasionally requires re-entry devices to access the true lumen distally, but limited information is available on factors predicting the success or failure of these devices. We evaluated the Outback LTD re-entry device (LuMend, Redwood City, Calif; acquired by Cordis Corp, Miami Lakes, Fla). A retrospective review of patients with femoropopliteal CTO from August 2006 to August 2009 was performed. Age, gender, occlusion length, site of re-entry, and the angle of the aortic bifurcation were recorded. Procedural angiograms were used to assign a calcification score (none, mild, moderate, severe) at the re-entry site. Univariate and multivariate logistic regression analyses were used to identify factors predicting failure of re-entry into the true lumen. Of 249 CTOs treated, the re-entry device was used 52 times (20.9%): 47 superficial femoral artery (SFA) occlusions and 5 combined SFA and popliteal artery occlusions (33 TransAtlantic InterSociety Consensus II type C and 18 type D lesions). Of 48 procedures with available angiograms for review, the target re-entry site was at the adductor canal in 30 (62.5%), the above-knee popliteal artery in 13 (27.1%), behind the knee joint in 4 (8.3%), and the mid-SFA in 2 (4.2%). Patients (54% men) were a mean age of 73.1 years. Re-entry was successful in 34 attempts (64.5%). Causes of failure included inability to re-enter the true lumen in 11 (61.1%), difficulty tracking the device over a wire in 3 (16.7%), acute angle of aortic bifurcation in 2 (11.1%), mechanical failure of the device in 1 (5.6%), and difficulty tracking the device through the lesion in 1 (5.6%). Moderate or severe calcification at the site of re-entry was the only significant predictor of failure (odds ratio, 6.3; 95% confidence interval, 1.45-24.48; P = .01). An aortic bifurcation angle ≥40° did trend toward predicting success (odds ratio, 0.23; 95% confidence interval, 0.05-1.02; P = .054). Although the Outback re-entry device can be successful in extending the applicability of endovascular management to difficult femoropopliteal occlusions, it is not uniformly successful in current clinical practice. Significant calcification at the proposed re-entry site is a strong predictor of failure. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

NHLBI's program for VAD therapy for moderately advanced heart failure: the REVIVE-IT pilot trial.

PubMed

Baldwin, J Timothy; Mann, Douglas L

2010-11-01

Ventricular assist devices (VADs) are used to bridge heart failure patients to transplantation, to allow their own hearts to recover, or as permanent ("destination") therapy. To date, the use of VADs has been limited to late-stage heart failure patients because of the associated device risks. In 2008, a National Heart, Lung, and Blood Institute (NHLBI) working group met to evaluate the treatment of heart failure using VADs and to advise the institute on how therapy for heart failure may be best advanced by clinical trials involving the devices. Recognizing the improvements in VAD technology and in patient care and selection over the past decade, the working group recommended that a trial be performed to assess the use of chronic VAD therapy in patients who are less ill than those currently eligible for destination therapy. The hypothesis proposed for the trial is that VAD therapy may improve both survival and quality of life in moderately advanced heart failure patients who are neither inotrope-dependent nor exercise-intolerant and have not yet developed serious consequences such as malnourishment, end-organ damage, and immobility. Based on the group's recommendations, NHLBI issued an RFP in 2009 for the REVIVE-IT Pilot Trail, which will serve to test the hypothesis and inform the pivotal trial. Published by Elsevier Inc.

Attempted salvage of infected cardiovascular implantable electronic devices: Are there clinical factors that predict success?

PubMed

Peacock, James E; Stafford, Jeanette M; Le, Katherine; Sohail, Muhammad Rizwan; Baddour, Larry M; Prutkin, Jordan M; Danik, Stephan B; Vikram, Holenarasipur R; Hernandez-Meneses, Marta; Miró, José M; Blank, Elisabeth; Naber, Christoph K; Carrillo, Roger G; Greenspon, Arnold J; Tseng, Chi-Hong; Uslan, Daniel Z

2018-03-08

Published guidelines mandate complete device removal in cases of cardiovascular implantable electronic device (CIED) infection. Clinical predictors of successful salvage of infected CIEDs have not been defined. Data from the Multicenter Electrophysiologic Device Infection Collaboration, a prospective, observational, multinational cohort study of CIED infection, were used to investigate whether clinical predictors of successful salvage of infected devices could be identified. Of 433 adult patients with CIED infections, 306 (71%) underwent immediate device explantation. Medical management with device retention and antimicrobial therapy was initially attempted in 127 patients (29%). "Early failure" of attempted salvage occurred in 74 patients (58%) who subsequently underwent device explantation during the index hospitalization. The remaining 53 patients (42%) in the attempted salvage group retained their CIED. Twenty-six (49%) had resolution of CIED infection (successful salvage group) whereas 27 patients (51%) experienced "late" salvage failure. Upon comparing the salvage failure group, early and late (N = 101), to the group experiencing successful salvage of an infected CIED (N = 26), no clinical or laboratory predictors of successful salvage were identified. However, by univariate analysis, coagulase-negative staphylococci as infecting pathogens (P = 0.0439) and the presence of a lead vegetation (P = 0.024) were associated with overall failed salvage. In patients with definite CIED infections, clinical and laboratory variables cannot predict successful device salvage. Until new data are forthcoming, device explantation should remain a mandatory and early management intervention in patients with CIED infection in keeping with existing expert guidelines unless medical contraindications exist or patients refuse device removal. © 2018 Wiley Periodicals, Inc.

Novel failure mechanism and improvement for split-gate trench MOSFET with large current under unclamped inductive switch stress

NASA Astrophysics Data System (ADS)

Tian, Ye; Yang, Zhuo; Xu, Zhiyuan; Liu, Siyang; Sun, Weifeng; Shi, Longxing; Zhu, Yuanzheng; Ye, Peng; Zhou, Jincheng

2018-04-01

In this paper, a novel failure mechanism under unclamped inductive switch (UIS) for Split-Gate Trench Metal Oxide Semiconductor Field Effect Transistor (MOSFET) with large current is investigated. The device sample is tested and analyzed in detail. The simulation results demonstrate that the nonuniform potential distribution of the source poly should be responsible for the failure. Three structures are proposed and verified available to improve the device UIS ruggedness by TCAD simulation. The best one of the structures the device with source metal inserting into source poly through contacts in the field oxide is carried out and measured. The results demonstrate that the optimized structure can balance the trade-off between the UIS ruggedness and the static characteristics.

Data processing device test apparatus and method therefor

DOEpatents

Wilcox, Richard Jacob; Mulig, Jason D.; Eppes, David; Bruce, Michael R.; Bruce, Victoria J.; Ring, Rosalinda M.; Cole, Jr., Edward I.; Tangyunyong, Paiboon; Hawkins, Charles F.; Louie, Arnold Y.

2003-04-08

A method and apparatus mechanism for testing data processing devices are implemented. The test mechanism isolates critical paths by correlating a scanning microscope image with a selected speed path failure. A trigger signal having a preselected value is generated at the start of each pattern vector. The sweep of the scanning microscope is controlled by a computer, which also receives and processes the image signals returned from the microscope. The value of the trigger signal is correlated with a set of pattern lines being driven on the DUT. The trigger is either asserted or negated depending the detection of a pattern line failure and the particular line that failed. In response to the detection of the particular speed path failure being characterized, and the trigger signal, the control computer overlays a mask on the image of the device under test (DUT). The overlaid image provides a visual correlation of the failure with the structural elements of the DUT at the level of resolution of the microscope itself.

Yield modeling of acoustic charge transport transversal filters

NASA Technical Reports Server (NTRS)

Kenney, J. S.; May, G. S.; Hunt, W. D.

1995-01-01

This paper presents a yield model for acoustic charge transport transversal filters. This model differs from previous IC yield models in that it does not assume that individual failures of the nondestructive sensing taps necessarily cause a device failure. A redundancy in the number of taps included in the design is explained. Poisson statistics are used to describe the tap failures, weighted over a uniform defect density distribution. A representative design example is presented. The minimum number of taps needed to realize the filter is calculated, and tap weights for various numbers of redundant taps are calculated. The critical area for device failure is calculated for each level of redundancy. Yield is predicted for a range of defect densities and redundancies. To verify the model, a Monte Carlo simulation is performed on an equivalent circuit model of the device. The results of the yield model are then compared to the Monte Carlo simulation. Better than 95% agreement was obtained for the Poisson model with redundant taps ranging from 30% to 150% over the minimum.

Endocarditis in left ventricular assist device

PubMed Central

Thyagarajan, Braghadheeswar; Kumar, Monisha Priyadarshini; Sikachi, Rutuja R; Agrawal, Abhinav

2016-01-01

Summary Heart failure is one of the leading causes of death in developed nations. End stage heart failure often requires cardiac transplantation for survival. The left ventricular assist device (LVAD) has been one of the biggest evolvements in heart failure management often serving as bridge to transplant or destination therapy in advanced heart failure. Like any other medical device, LVAD is associated with complications with infections being reported in many patients. Endocarditis developing secondary to the placement of LVAD is not a frequent, serious and difficult to treat condition with high morbidity and mortality. Currently, there are few retrospective studies and case reports reporting the same. In our review, we found the most common cause of endocarditis in LVAD was due to bacteria. Both bacterial and fungal endocarditis were associated with high morbidity and mortality. In this review we will be discussing the risk factors, organisms involved, diagnostic tests, management strategies, complications, and outcomes in patients who developed endocarditis secondary to LVAD placement. PMID:27672540

Monitoring patients with continuous-flow ventricular assist devices outside of the intensive care unit: novel challenges to bedside nursing.

PubMed

O'Shea, Genevieve; Teuteberg, Jeffrey J; Severyn, Donald A

2013-03-01

Ventricular assist devices provide therapeutic options for patients with severe heart failure who have exhausted available medical therapies. With restoration of organ perfusion with ventricular assist devices, the heart failure resolves and quality of life and functional status improve. The current generation of continuous-flow devices present novel challenges to the clinical assessment of patients by substantially reducing or nearly eliminating any palpable pulse. Patients therefore generally have inadequate arterial pulsatility for most noninvasive monitoring devices such as pulse oximeters or automated blood pressure cuffs to work accurately. This article describes the function of continuous-flow devices and how this function affects common monitoring options, as well as how to clinically assess recipients of continuous-flow devices to promptly identify those whose condition may be deteriorating or who may be receiving inadequate perfusion.

Physical Exercise and Patients with Chronic Renal Failure: A Meta-Analysis.

PubMed

Qiu, Zhenzhen; Zheng, Kai; Zhang, Haoxiang; Feng, Ji; Wang, Lizhi; Zhou, Hao

2017-01-01

Chronic renal failure is a severe clinical problem which has some significant socioeconomic impact worldwide and hemodialysis is an important way to maintain patients' health state, but it seems difficult to get better in short time. Considering these, the aim in our research is to update and evaluate the effects of exercise on the health of patients with chronic renal failure. The databases were used to search for the relevant studies in English or Chinese. And the association between physical exercise and health state of patients with chronic renal failure has been investigated. Random-effect model was used to compare the physical function and capacity in exercise and control groups. Exercise is helpful in ameliorating the situation of blood pressure in patients with renal failure and significantly reduces VO 2 in patients with renal failure. The results of subgroup analyses show that, in the age >50, physical activity can significantly reduce blood pressure in patients with renal failure. The activity program containing warm-up, strength, and aerobic exercises has benefits in blood pressure among sick people and improves their maximal oxygen consumption level. These can help patients in physical function and aerobic capacity and may give them further benefits.

Physical Exercise and Patients with Chronic Renal Failure: A Meta-Analysis

PubMed Central

Qiu, Zhenzhen; Zheng, Kai; Zhang, Haoxiang; Feng, Ji; Wang, Lizhi

2017-01-01

Chronic renal failure is a severe clinical problem which has some significant socioeconomic impact worldwide and hemodialysis is an important way to maintain patients' health state, but it seems difficult to get better in short time. Considering these, the aim in our research is to update and evaluate the effects of exercise on the health of patients with chronic renal failure. The databases were used to search for the relevant studies in English or Chinese. And the association between physical exercise and health state of patients with chronic renal failure has been investigated. Random-effect model was used to compare the physical function and capacity in exercise and control groups. Exercise is helpful in ameliorating the situation of blood pressure in patients with renal failure and significantly reduces VO2 in patients with renal failure. The results of subgroup analyses show that, in the age >50, physical activity can significantly reduce blood pressure in patients with renal failure. The activity program containing warm-up, strength, and aerobic exercises has benefits in blood pressure among sick people and improves their maximal oxygen consumption level. These can help patients in physical function and aerobic capacity and may give them further benefits. PMID:28316986

Model-Based Anomaly Detection for a Transparent Optical Transmission System

NASA Astrophysics Data System (ADS)

Bengtsson, Thomas; Salamon, Todd; Ho, Tin Kam; White, Christopher A.

In this chapter, we present an approach for anomaly detection at the physical layer of networks where detailed knowledge about the devices and their operations is available. The approach combines physics-based process models with observational data models to characterize the uncertainties and derive the alarm decision rules. We formulate and apply three different methods based on this approach for a well-defined problem in optical network monitoring that features many typical challenges for this methodology. Specifically, we address the problem of monitoring optically transparent transmission systems that use dynamically controlled Raman amplification systems. We use models of amplifier physics together with statistical estimation to derive alarm decision rules and use these rules to automatically discriminate between measurement errors, anomalous losses, and pump failures. Our approach has led to an efficient tool for systematically detecting anomalies in the system behavior of a deployed network, where pro-active measures to address such anomalies are key to preventing unnecessary disturbances to the system's continuous operation.

Follow-up of the original cohort with the Ahmed glaucoma valve implant.

PubMed

Topouzis, F; Coleman, A L; Choplin, N; Bethlem, M M; Hill, R; Yu, F; Panek, W C; Wilson, M R

1999-08-01

To study the long-term results of the Ahmed glaucoma valve implant in patients with complicated glaucoma in whom short-term results have been reported. In this multicenter study, we analyzed the long-term outcome of a cohort of 60 eyes from 60 patients in whom the Ahmed glaucoma valve was implanted. Failure was characterized by at least one of the following: intraocular pressure greater than 21 mm Hg at both of the last two visits less than 6 mm Hg at both of the last two visits, loss of light perception, additional glaucoma surgery, devastating complications, and removal or replacement of the Ahmed glaucoma valve implant. Devastating complications included chronic hypotony, retinal detachment, malignant glaucoma, endophthalmitis, and phthisis bulbi; we also report results that add corneal complications (corneal decompensation or edema, corneal graft failure) as defining a devastating complication. The mean follow-up time for the 60 eyes was 30.5 months (range, 2.1 to 63.5). When corneal complications were included in the definition of failure, 26 eyes (43%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 76%, 68%, 54%, and 45%, respectively. When corneal complications were excluded from the definition of failure, 13 eyes (21.5%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 87%, 82%, 76%, and 76%, respectively. Most of the failures after 12 months of postoperative follow-up were because of corneal complications. The long-term performance of the Ahmed glaucoma valve implant is comparable to other drainage devices. More than 12 months after the implantation of the Ahmed glaucoma valve implant, the most frequent adverse outcome was corneal decompensation or corneal graft failure. These corneal problems may be secondary to the type of eyes that have drainage devices or to the drainage device itself. Further investigation is needed to identify the reasons that corneal problems follow drainage device implantation.

Bone suture anchor fixation in the lower extremity: a review of insertion principles and a comparative biomechanical evaluation.

PubMed

Scranton, Pierce E; Lawhon, S Michael; McDermott, John E

2005-07-01

Suture anchors have been developed for the fixation of ligaments, capsules, or tendons to bone. These devices have led to improved fixation, smaller incisions, earlier limb mobility, and improved outcomes. They were originally developed for use in shoulder reconstructions but are now used in almost all extremities. In the lower leg they are used in the tibia, the talus, the calcaneus, tarsal bones, and phalanges. Nevertheless, techniques for insertion and mechanisms of failure are not well described. Five suture anchors were studied to determine the pullout strength in four distal cadaver femurs and four proximal cadaver tibias from 55- and 62-year-old males. Eight hundred ninety Newton line was used, testing the anchors to failure with an Instron testing device (Instron, Norwood, MA). The anchor devices were inserted randomly and tested blindly (12 tests per anchor device, 60 tests in all). Two anchors in each group tested failed at low loads. Both types of plastic anchors had failures at the eyelet. Average pullout strength varied from 85.4 to 185.6 N. Insertion techniques are specific for each device, and they must be followed for optimal fixation. In this study, in all five groups of anchors tested two of the 12 anchors in each group failed with minimal force. On the basis of this finding we recommend that, if suture anchor fixation is necessary, at least two anchors should be used. Since there appears to be a percentage of failure in all devices, the second anchor can serve as a backup. It is imperative that surgeons be familiar with the insertion techniques of each device before use.

Effects of structural modification on reliability of nanoscale nitride HEMTs

NASA Astrophysics Data System (ADS)

Gaddipati, Vamsi Mohan

AlGaN based nanoscale high-electron-mobility transistors (HEMTs) are the next generation of transistor technology that features the unique combination of higher power, wider bandwidth, low noise, higher efficiency, and temperature/radiation hardness than conventional AlGaAs and Si based technologies. However, as evidenced by recent stress tests, reliability of these devices (characterized by a gradual decrease in the output current/power leading to failure of the device in just tens of hours of operation) remains a major concern. Although, in these tests, physical damages were clearly visible in the device, the root cause and nature of these damages have not yet been fully assessed experimentally. Therefore, a comprehensive theoretical study of the physical mechanisms responsible for degradation of AlGaN HEMTs is essential before these devices are deployed in targeted applications. The main objective of the proposed research is to computationally investigate how degradation of state-of-the-art nanoscale AlGaN HEMTs is governed by an intricate and dynamical coupling of thermo-electromechanical processes at different length (atoms-to-transistor) and time (femtosecondto- hours) scales while operating in high voltage, large mechanical, and high temperature/radiation stresses. This work centers around a novel hypotheses as follows: High voltage applied to AlGaN HEMT causes excessive internal heat dissipation, which triggers gate metal diffusion into the semiconducting barrier layer and structural modifications (defect ii formation) leading to diminished polarization induced charge density and output current. Since the dynamical system to be studied is complex, chaotic (where the evolution rule is guided by atomicity of the underlying material), and involve coupled physical processes, an in-house multiscale simulator (QuADS 3-D) has been employed and augmented, where material parameters are obtained atomistically using firstprinciples, structural relaxation and defect formations will be modeled by integrating molecular dynamics, and the influence of atomistic processes on charge and phonon transport and current degradation will be simulated using a coupled drift-diffusionthermodynamic framework.

Left ventricular assist device and drug therapy for the reversal of heart failure.

PubMed

Birks, Emma J; Tansley, Patrick D; Hardy, James; George, Robert S; Bowles, Christopher T; Burke, Margaret; Banner, Nicholas R; Khaghani, Asghar; Yacoub, Magdi H

2006-11-02

In patients with severe heart failure, prolonged unloading of the myocardium with the use of a left ventricular assist device has been reported to lead to myocardial recovery in small numbers of patients for varying periods of time. Increasing the frequency and durability of myocardial recovery could reduce or postpone the need for subsequent heart transplantation. We enrolled 15 patients with severe heart failure due to nonischemic cardiomyopathy and with no histologic evidence of active myocarditis. All had markedly reduced cardiac output and were receiving inotropes. The patients underwent implantation of left ventricular assist devices and were treated with lisinopril, carvedilol, spironolactone, and losartan to enhance reverse remodeling. Once regression of left ventricular enlargement had been achieved, the beta2-adrenergic-receptor agonist clenbuterol was administered to prevent myocardial atrophy. Eleven of the 15 patients had sufficient myocardial recovery to undergo explantation of the left ventricular assist device a mean (+/-SD) of 320+/-186 days after implantation of the device. One patient died of intractable arrhythmias 24 hours after explantation; another died of carcinoma of the lung 27 months after explantation. The cumulative rate of freedom from recurrent heart failure among the surviving patients was 100% and 88.9% 1 and 4 years after explantation, respectively. The quality of life as assessed by the Minnesota Living with Heart Failure Questionnaire score at 3 years was nearly normal. Fifty-nine months after explantation, the mean left ventricular ejection fraction was 64+/-12%, the mean left ventricular end-diastolic diameter was 59.4+/-12.1 mm, the mean left ventricular end-systolic diameter was 42.5+/-13.2 mm, and the mean maximal oxygen uptake with exercise was 26.3+/-6.0 ml per kilogram of body weight per minute. In this single-center study, we found that sustained reversal of severe heart failure secondary to nonischemic cardiomyopathy could be achieved in selected patients with the use of a left ventricular assist device and a specific pharmacologic regimen. Copyright 2006 Massachusetts Medical Society.

Accelerated Implantable Defibrillator Battery Depletion Secondary to Lithium Cluster Formation: A Case Series.

PubMed

Aggarwal, Ashim; Sarmiento, Joseph J; Charles, David R; Parr, Alan R; Baman, Timir S

2016-04-01

Device failure from unanticipated and precipitous battery depletion is uncommon but can be life-threatening. Multiple mechanisms of battery failure have been previously described in the medical literature. However, in this current case series, we describe the largest cohort of patients (n = 4) with St. Jude (St. Paul, MN, USA) early implantable defibrillator battery depletion attributable to lithium cluster formation causing short circuit and high current drain. Clinicians must be aware of this occult cause of device failure and more studies are needed to determine its true prevalence. © 2015 Wiley Periodicals, Inc.

49 CFR 220.38 - Communication equipment failure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Communication equipment failure. 220.38 Section 220.38 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 220.38 Communication equipment failure. (a) Any radio or wireless communication device found not to be...

49 CFR 220.38 - Communication equipment failure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Communication equipment failure. 220.38 Section 220.38 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 220.38 Communication equipment failure. (a) Any radio or wireless communication device found not to be...

Single-Event Effects in Silicon and Silicon Carbide Power Devices

NASA Technical Reports Server (NTRS)

Lauenstein, Jean-Marie; Casey, Megan C.; LaBel, Kenneth A.; Topper, Alyson D.; Wilcox, Edward P.; Kim, Hak; Phan, Anthony M.

2014-01-01

NASA Electronics Parts and Packaging program-funded activities over the past year on single-event effects in silicon and silicon carbide power devices are presented, with focus on SiC device failure signatures.

75 FR 44172 - Neurological and Physical Medicine Devices; Designation of Special Controls for Certain Class II...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-28

... [Docket No. FDA-2009-N-0493] RIN 0910-ZA37 Neurological and Physical Medicine Devices; Designation of... document proposed to amend certain neurological and physical medicine device regulations to establish... to amend certain neurological device and physical medicine device regulations to establish special...

Current State and Future Perspectives of Energy Sources for Totally Implantable Cardiac Devices.

PubMed

Bleszynski, Peter A; Luc, Jessica G Y; Schade, Peter; PhilLips, Steven J; Tchantchaleishvili, Vakhtang

There is a large population of patients with end-stage congestive heart failure who cannot be treated by means of conventional cardiac surgery, cardiac transplantation, or chronic catecholamine infusions. Implantable cardiac devices, many designated as destination therapy, have revolutionized patient care and outcomes, although infection and complications related to external power sources or routine battery exchange remain a substantial risk. Complications from repeat battery replacement, power failure, and infections ultimately endanger the original objectives of implantable biomedical device therapy - eliminating the intended patient autonomy, affecting patient quality of life and survival. We sought to review the limitations of current cardiac biomedical device energy sources and discuss the current state and trends of future potential energy sources in pursuit of a lifelong fully implantable biomedical device.

A quantitative thermal and thermomechanical analysis for design optimization and robustness assessment of microassembled high power Yb:CaF2 thin-disk Laser

NASA Astrophysics Data System (ADS)

Joly, S.; Lemesre, M.-A.; Levrier, B.; Lyszyk, C.; Plano, B.; Courjaud, A.; Taira, T.; Bechou, L.

2018-09-01

While considerable effort in the field of high power laser research has been dedicated to evolving thin-disk Lasers into the kilowatt range, thermal and residual stress management remain a critical issue and need to be addressed. In this paper, a quantitative thermal and thermomechanical analysis is presented for design optimization and robustness of high power diode pumped thin-disk ytterbium Lasers based on thermal and thermomechanical Finite Element Method (FEM) simulations. In particular, Yb:CaF2 Lasers are examined with respect to the design and selection of the bonding interface material. Results propose the use of a metallic Au80Sn20 hard solder of greater than 20 μm thickness as a superior solution to adhesive bonding for the prevention of Laser crystal failure under high optical pumping power while maintaining sufficient resistance to mechanical strain. Thermal IR characterizations under "safe" CW pumping power validate our predicted FEM Multiphysics models. Finally, an essentially void-free Au80Sn20 soldering process has been demonstrated for the mounting of Yb:CaF2 crystals onto a CuW heat sink. He currently acts as a Full Professor in electronics and physics at the University of Bordeaux. His research field addresses characterization, physical and failure mechanisms modeling and methods for reliability prediction of optoelectronic/photonic micro and nano-assemblied devices (LEDs, laser diodes, fiber laser, optical amplifier, photodetectors, fibered optical module…) for different applications (telecommunications, medical, space...). Research interests focus on Design for Reliability at the early stage of the development of the device including design, fabrication, characterization and aging effects on packaged optoelectronic materials and functions which involves the exploration of the physics of the light-matter interactions as well as the understanding degradation processes. Since 2010 is currently the manager of the "Reliability Assessment of Micro and Nano-assemblied Devices" Research Group (EDMiNA) at IMS Laboratory. He is the author or co-author of more than 180 regular papers and international conferences. He has also chaired different sessions in international conferences and acts as a reviewer of peer-reviewed journals from Elsevier (Microelectronics Reliab., Optics and Laser Technology…), IOP (Optics Letters), IEEE (Photonics Technology Letters, Devices and Materials Reliability, Electron Devices…). He has managed over 20 PhDs grants and post-docs addressing projects focusing both on fundamental aspects as well as applied research with national and European industrial partnerships with over 5M€ of funding. He is involved in several French and European committees acting as reviewer expert for National Research Agency (ANR) and CATRENE/EURIPIDES programs. Since March 2016, he is appointed Visiting Professor at the French-Canadian Joint Lab LN2 - University of Sherbrooke (Qc, Canada) working on packaging and design for reliability of devices and systems for photonic applications.

Novel mechanism of premature battery failure due to lithium cluster formation in implantable cardioverter-defibrillators.

PubMed

Pokorney, Sean D; Greenfield, Ruth Ann; Atwater, Brett D; Daubert, James P; Piccini, Jonathan P

2014-12-01

Battery failure is an uncommon complication of implantable cardioverter-defibrillators (ICDs), but unanticipated battery depletion can have life-threatening consequences. The purpose of this study was to describe the prevalence of a novel mechanism of battery failure in St. Jude Medical Fortify and Unify ICDs. Cases of premature Fortify battery failure from a single center are reported. A search (January 1, 2010 through November 30, 2013) for Fortify and Unify premature batter failure was conducted of the Food and Drug Administration's Manufacturer and User Facility Device Experience Database (MAUDE). These findings were supplemented with information provided by St. Jude Medical. Premature battery failure for 2 Fortify ICDs in our practice were attributed to the presence of lithium clusters near the cathode, causing a short circuit and high current drain. The prevalence of this mechanism of premature battery failure was 0.6% in our practice. A MAUDE search identified 39 cases of Fortify (30) and Unify (9) premature battery depletion confirmed by the manufacturer, representing a 0.03% prevalence. Four additional Fortify and 2 Unify cases were identified in MAUDE as suspected premature battery depletion, but in these cases the pulse generator was not returned to the manufacturer for evaluation. St. Jude Medical identified 10 cases of premature battery failure due to lithium clusters in Fortify devices (9) and Unify devices (1), representing a 0.004% prevalence. The deposition of lithium clusters near the cathode is a novel mechanism of premature battery failure. The prevalence of this problem is unknown. Providers should be aware of this mechanism for patient management. Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Prediction of L70 lumen maintenance and chromaticity for LEDs using extended Kalman filter models

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

Lall, Pradeep; Wei, Junchao; Davis, Lynn

2013-09-30

Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. Traditional light sources “burn out” at end-of-life. For an incandescent bulb, the lamp life is definedmore » by B50 life. However, the LEDs have no filament to “burn”. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. Presently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. The underlying TM-21 Model may not capture the failure physics in presence of multiple failure mechanisms. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed. In this paper, Kalman Filter (KF) and Extended Kalman Filters (EKF) have been used to develop a 70-percent Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. Ten-thousand hour LM-80 test data for various LEDs have been used for model development. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. The measured state variable has been related to the underlying damage using physics-based models. Life prediction of L70 life for the LEDs used in SSL luminaires from KF and EKF based models have been compared with the TM-21 model predictions and experimental data.« less

L70 life prediction for solid state lighting using Kalman Filter and Extended Kalman Filter based models

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

Lall, Pradeep; Wei, Junchao; Davis, Lynn

2013-08-08

Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. Traditional light sources “burn out” at end-of-life. For an incandescent bulb, the lamp life is definedmore » by B50 life. However, the LEDs have no filament to “burn”. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. Presently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. The underlying TM-21 Model may not capture the failure physics in presence of multiple failure mechanisms. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed. In this paper, Kalman Filter (KF) and Extended Kalman Filters (EKF) have been used to develop a 70-percent Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. Ten-thousand hour LM-80 test data for various LEDs have been used for model development. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. The measured state variable has been related to the underlying damage using physics-based models. Life prediction of L70 life for the LEDs used in SSL luminaires from KF and EKF based models have been compared with the TM-21 model predictions and experimental data.« less

Use of a vessel sealant device for cystic duct ligation in the dog.

PubMed

Marvel, Sarah; Monnet, Eric

2014-11-01

To compare a vessel sealant device to hemostatic clips for cystic duct ligation in a canine cadaveric model. Experimental. Hepatobiliary systems were collected from normal dogs. A microtip pressure transducer was inserted into the common bile duct and a 20-24 g intravenous catheter was placed in a hepatic duct. The cystic duct was ligated with 1 of 3 techniques: vessel sealant device (VSD), 10 mm medium Endoclips™, or 10 mm large Endoclips™ with 6 specimens in each group. Methylene blue was infused until failure, which was recorded as seal/clip failure or retrograde movement of methylene blue into the liver. Mean failure pressure of the medium endoclip group was significantly lower than the large endoclip group (P = .014). There was no difference between the failure pressure of the VSD group and the medium and large endoclip groups (P = .097, P = .34, respectively). Failure by leakage at the cut surface of the cystic duct occurred in 2 specimens in the medium endoclip group while all others failed by retrograde flow of the methylene blue through the hepatic ducts. The vessel sealant device appears comparable to large endoclips for closure of the cystic duct in an acute cadaveric model, while medium endoclips may not fully compress or span the diameter of a cystic duct in large breed dogs and leak at lower pressures. © Copyright 2014 by The American College of Veterinary Surgeons.

Depressive symptoms and the relationship of inflammation to physical signs and symptoms in heart failure patients.

PubMed

Heo, Seongkum; Moser, Debra K; Pressler, Susan J; Dunbar, Sandra B; Dekker, Rebecca L; Lennie, Terry A

2014-09-01

Depressive symptoms in patients with heart failure can affect the relationship between physical signs and symptoms and inflammation. To examine the relationship between soluble tumor necrosis factor receptor I and physical signs and symptoms and the effects of depressive symptoms on this relationship in patients with heart failure. Data on physical signs and symptoms (Symptom Status Questionnaire-Heart Failure), depressive symptoms (Beck Depression Inventory-II), and levels of the receptor (blood samples) were collected from 145 patients with heart failure. Data on the receptor were square root transformed to achieve normality. Patients were divided into 2 groups according to their scores for depressive symptoms (nondepressed <14 and depressed ≥14). Hierarchical multiple regression was used to analyze the data. In the total sample, with controls for covariates, higher levels of the receptor were significantly related to more severe physical signs and symptoms (F = 7.915; P < .001). In subgroup analyses, with controls for covariates, levels of the receptor were significantly related to physical signs and symptoms only in the patients without depression (F = 3.174; P = .005). Both depressive symptoms and inflammation should be considered along with physical signs and symptoms in patients with heart failure. Further studies are needed to determine the effects of improvement in inflammation on improvement in physical signs and symptoms, with consideration given to the effects of depressive symptoms. ©2014 American Association of Critical-Care Nurses.

CIRSE Vascular Closure Device Registry

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

Reekers, Jim A., E-mail: j.a.reekers@amc.uva.nl; Mueller-Huelsbeck, Stefan; Libicher, Martin

2011-02-15

Purpose: Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. Methods: The CIRSE registry of closure devices with an anchor and a plug started in January 2009 and ended in August 2009. A total of 1,107 patients were included in the registry. Results: Deployment success was 97.2%. Deployment failure specified to access type was 8.8% [95% confidence interval (95% CI) 5.0-14.5] for antegrade access and 1.8% (95% CI 1.1-2.9) for retrograde access (Pmore » = 0.001). There was no difference in deployment failure related to local PVD at the access site. Calcification was a reason for deployment failure in only <0.5% of patients. Postdeployment bleeding occurred in 6.4%, and most these (51.5%) could be managed with light manual compression. During follow-up, other device-related complications were reported in 1.3%: seven false aneurysms, three hematoma >5.9 cm, and two vessel occlusions. Conclusion: The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters.« less

CIRSE Vascular Closure Device Registry

PubMed Central

Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

2010-01-01

Purpose Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. Methods The CIRSE registry of closure devices with an anchor and a plug started in January 2009 and ended in August 2009. A total of 1,107 patients were included in the registry. Results Deployment success was 97.2%. Deployment failure specified to access type was 8.8% [95% confidence interval (95% CI) 5.0–14.5] for antegrade access and 1.8% (95% CI 1.1–2.9) for retrograde access (P = 0.001). There was no difference in deployment failure related to local PVD at the access site. Calcification was a reason for deployment failure in only <0.5% of patients. Postdeployment bleeding occurred in 6.4%, and most these (51.5%) could be managed with light manual compression. During follow-up, other device-related complications were reported in 1.3%: seven false aneurysms, three hematoma >5.9 cm, and two vessel occlusions. Conclusion The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters. PMID:20981425

Incidence of School Failure According to Baseline Leisure-Time Physical Activity Practice: Prospective Study

PubMed Central

Rombaldi, Airton J.; Clark, Valerie L.; Reichert, Felipe F.; Araújo, Cora L.P.; Assunção, Maria C.; Menezes, Ana M.B.; Horta, Bernardo L.; Hallal, Pedro C.

2012-01-01

Purpose To evaluate the prospective association between leisure-time physical activity practice at 11 years of age and incidence of school failure from 11 to 15 years of age. Methods The sample comprised >4,300 adolescents followed up from birth to 15 years of age participating in a birth cohort study in Pelotas, Brazil. The incidence of school failure from age 11 to 15 years was calculated by first excluding from the analyses all subjects who experienced a school failure before 11 years of age, and then categorizing as “positive” all those who reported repeating a grade at school from 11 to 15 years of age. Leisure-time physical activity was measured using a validated questionnaire. Results The incidence of school failure was 47.9% among boys and 38.2% among girls. Adolescents in the top quartile of leisure-time physical activity practice at 11 years of age had a higher likelihood of school failure (OR: 1.36; 95% CI: 1.06, 1.75) compared with the least active adolescents. In adjusted analyses stratified by sex, boys in the top quartile of leisure-time physical activity practice at 11 years of age were also more likely to have failed at school from age 11 to 15 years (OR: 1.60; 95% CI: 1.09, 2.33). Conclusions Adolescents allocating >1,000 min/wk to leisure-time physical activity were more likely to experience a school failure from 11 to 15 years of age. Although this finding does not advocate against physical activity promotion, it indicates that excess time allocated to physical activity may jeopardize school performance among adolescents. PMID:23283155

Incidence of school failure according to baseline leisure-time physical activity practice: prospective study.

PubMed

Rombaldi, Airton J; Clark, Valerie L; Reichert, Felipe F; Araújo, Cora L P; Assunção, Maria C; Menezes, Ana M B; Horta, Bernardo L; Hallal, Pedro C

2012-12-01

To evaluate the prospective association between leisure-time physical activity practice at 11 years of age and incidence of school failure from 11 to 15 years of age. The sample comprised >4,300 adolescents followed up from birth to 15 years of age participating in a birth cohort study in Pelotas, Brazil. The incidence of school failure from age 11 to 15 years was calculated by first excluding from the analyses all subjects who experienced a school failure before 11 years of age, and then categorizing as "positive" all those who reported repeating a grade at school from 11 to 15 years of age. Leisure-time physical activity was measured using a validated questionnaire. The incidence of school failure was 47.9% among boys and 38.2% among girls. Adolescents in the top quartile of leisure-time physical activity practice at 11 years of age had a higher likelihood of school failure (OR: 1.36; 95% CI: 1.06, 1.75) compared with the least active adolescents. In adjusted analyses stratified by sex, boys in the top quartile of leisure-time physical activity practice at 11 years of age were also more likely to have failed at school from age 11 to 15 years (OR: 1.60; 95% CI: 1.09, 2.33). Adolescents allocating >1,000 min/wk to leisure-time physical activity were more likely to experience a school failure from 11 to 15 years of age. Although this finding does not advocate against physical activity promotion, it indicates that excess time allocated to physical activity may jeopardize school performance among adolescents. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

A review on locomotion robophysics: the study of movement at the intersection of robotics, soft matter and dynamical systems.

PubMed

Aguilar, Jeffrey; Zhang, Tingnan; Qian, Feifei; Kingsbury, Mark; McInroe, Benjamin; Mazouchova, Nicole; Li, Chen; Maladen, Ryan; Gong, Chaohui; Travers, Matt; Hatton, Ross L; Choset, Howie; Umbanhowar, Paul B; Goldman, Daniel I

2016-11-01

Discovery of fundamental principles which govern and limit effective locomotion (self-propulsion) is of intellectual interest and practical importance. Human technology has created robotic moving systems that excel in movement on and within environments of societal interest: paved roads, open air and water. However, such devices cannot yet robustly and efficiently navigate (as animals do) the enormous diversity of natural environments which might be of future interest for autonomous robots; examples include vertical surfaces like trees and cliffs, heterogeneous ground like desert rubble and brush, turbulent flows found near seashores, and deformable/flowable substrates like sand, mud and soil. In this review we argue for the creation of a physics of moving systems-a 'locomotion robophysics'-which we define as the pursuit of principles of self-generated motion. Robophysics can provide an important intellectual complement to the discipline of robotics, largely the domain of researchers from engineering and computer science. The essential idea is that we must complement the study of complex robots in complex situations with systematic study of simplified robotic devices in controlled laboratory settings and in simplified theoretical models. We must thus use the methods of physics to examine both locomotor successes and failures using parameter space exploration, systematic control, and techniques from dynamical systems. Using examples from our and others' research, we will discuss how such robophysical studies have begun to aid engineers in the creation of devices that have begun to achieve life-like locomotor abilities on and within complex environments, have inspired interesting physics questions in low dimensional dynamical systems, geometric mechanics and soft matter physics, and have been useful to develop models for biological locomotion in complex terrain. The rapidly decreasing cost of constructing robot models with easy access to significant computational power bodes well for scientists and engineers to engage in a discipline which can readily integrate experiment, theory and computation.

A review on locomotion robophysics: the study of movement at the intersection of robotics, soft matter and dynamical systems

NASA Astrophysics Data System (ADS)

Aguilar, Jeffrey; Zhang, Tingnan; Qian, Feifei; Kingsbury, Mark; McInroe, Benjamin; Mazouchova, Nicole; Li, Chen; Maladen, Ryan; Gong, Chaohui; Travers, Matt; Hatton, Ross L.; Choset, Howie; Umbanhowar, Paul B.; Goldman, Daniel I.

2016-11-01

Discovery of fundamental principles which govern and limit effective locomotion (self-propulsion) is of intellectual interest and practical importance. Human technology has created robotic moving systems that excel in movement on and within environments of societal interest: paved roads, open air and water. However, such devices cannot yet robustly and efficiently navigate (as animals do) the enormous diversity of natural environments which might be of future interest for autonomous robots; examples include vertical surfaces like trees and cliffs, heterogeneous ground like desert rubble and brush, turbulent flows found near seashores, and deformable/flowable substrates like sand, mud and soil. In this review we argue for the creation of a physics of moving systems—a ‘locomotion robophysics’—which we define as the pursuit of principles of self-generated motion. Robophysics can provide an important intellectual complement to the discipline of robotics, largely the domain of researchers from engineering and computer science. The essential idea is that we must complement the study of complex robots in complex situations with systematic study of simplified robotic devices in controlled laboratory settings and in simplified theoretical models. We must thus use the methods of physics to examine both locomotor successes and failures using parameter space exploration, systematic control, and techniques from dynamical systems. Using examples from our and others’ research, we will discuss how such robophysical studies have begun to aid engineers in the creation of devices that have begun to achieve life-like locomotor abilities on and within complex environments, have inspired interesting physics questions in low dimensional dynamical systems, geometric mechanics and soft matter physics, and have been useful to develop models for biological locomotion in complex terrain. The rapidly decreasing cost of constructing robot models with easy access to significant computational power bodes well for scientists and engineers to engage in a discipline which can readily integrate experiment, theory and computation.

Physical Functioning, Physical Activity, Exercise Self-Efficacy, and Quality of Life Among Individuals With Chronic Heart Failure in Korea: A Cross-Sectional Descriptive Study.

PubMed

Lee, Haejung; Boo, Sunjoo; Yu, Jihyoung; Suh, Soon-Rim; Chun, Kook Jin; Kim, Jong Hyun

2017-04-01

Both the beneficial relationship between exercise and quality of life and the important role played by exercise self-efficacy in maintaining an exercise regimen among individuals with chronic heart failure are well known. However, most nursing interventions for Korean patients with chronic heart failure focus only on providing education related to risk factors and symptoms. Little information is available regarding the influence of physical functions, physical activity, and exercise self-efficacy on quality of life. This study was conducted to examine the impact of physical functioning, physical activity, and exercise self-efficacy on quality of life among individuals with chronic heart failure. This study used a cross-sectional descriptive design. Data were collected from 116 outpatients with chronic heart failure in Korea. Left ventricular ejection fraction and New York Heart Association classifications were chart reviewed. Information pertaining to levels of physical activity, exercise self-efficacy, and quality of life were collected using self-administered questionnaires. Data were analyzed using descriptive statistics, t tests, analyses of variance, correlations, and hierarchical multiple regressions. About 60% of participants were physically inactive, and most showed relatively low exercise self-efficacy. The mean quality-of-life score was 80.09. The significant correlates for quality of life were poverty, functional status, physical inactivity, and exercise self-efficacy. Collectively, these four variables accounted for 50% of the observed total variance in quality of life. Approaches that focus on enhancing exercise self-efficacy may improve patient-centered outcomes in those with chronic heart failure. In light of the low level of exercise self-efficacy reported and the demonstrated ability of this factor to predict quality of life, the development of effective strategies to enhance exercise self-efficacy offers a novel and effective approach to improving the quality of life of patients with chronic heart failure. Nurses should be proactive in advising patients with chronic heart failure to be more physically active and to enhance their self-confidence in diverse ways.

14 CFR 29.687 - Spring devices.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Spring devices. 29.687 Section 29.687... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 29.687 - Spring devices.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Spring devices. 29.687 Section 29.687... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 29.687 - Spring devices.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Spring devices. 29.687 Section 29.687... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 27.687 - Spring devices.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Spring devices. 27.687 Section 27.687... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 27.687 - Spring devices.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Spring devices. 27.687 Section 27.687... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 27.687 - Spring devices.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Spring devices. 27.687 Section 27.687... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 29.687 - Spring devices.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Spring devices. 29.687 Section 29.687... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

14 CFR 27.687 - Spring devices.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Spring devices. 27.687 Section 27.687... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.687 Spring devices. (a) Each control system spring device whose failure could cause flutter or other unsafe characteristics...

Stochastic Model of Clogging in a Microfluidic Cell Sorter

NASA Astrophysics Data System (ADS)

Fai, Thomas; Rycroft, Chris

2016-11-01

Microfluidic devices for sorting cells by deformability show promise for various medical purposes, e.g. detecting sickle cell anemia and circulating tumor cells. One class of such devices consists of a two-dimensional array of narrow channels, each column containing several identical channels in parallel. Cells are driven through the device by an applied pressure or flow rate. Such devices allows for many cells to be sorted simultaneously, but cells eventually clog individual channels and change the device properties in an unpredictable manner. In this talk, we propose a stochastic model for the failure of such microfluidic devices by clogging and present preliminary theoretical and computational results. The model can be recast as an ODE that exhibits finite time blow-up under certain conditions. The failure time distribution is investigated analytically in certain limiting cases, and more realistic versions of the model are solved by computer simulation.

Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement

PubMed Central

Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed. PMID:29552039

Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement.

PubMed

Huenges, Katharina; Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed.

VHSIC/VHSIC-Like Reliability Prediction Modeling

DTIC Science & Technology

1989-10-01

prediction would require ’ kowledge of event statistics as well as device robustness. Ii1 Additionally, although this is primarily a theoretical, bottom...Degradation in Section 5.3 P = Power PDIP = Plastic DIP P(f) = Probability of Failure due to EOS or ESD P(flc) = Probability of Failure given Contact from an...the results of those stresses: Device Stress Part Number Power Dissipation Manufacturer Test Type Part Description Junction Teniperatune Package Type

Reliability Issues and Solutions in Flexible Electronics Under Mechanical Fatigue

NASA Astrophysics Data System (ADS)

Yi, Seol-Min; Choi, In-Suk; Kim, Byoung-Joon; Joo, Young-Chang

2018-07-01

Flexible devices are of significant interest due to their potential expansion of the application of smart devices into various fields, such as energy harvesting, biological applications and consumer electronics. Due to the mechanically dynamic operations of flexible electronics, their mechanical reliability must be thoroughly investigated to understand their failure mechanisms and lifetimes. Reliability issue caused by bending fatigue, one of the typical operational limitations of flexible electronics, has been studied using various test methodologies; however, electromechanical evaluations which are essential to assess the reliability of electronic devices for flexible applications had not been investigated because the testing method was not established. By employing the in situ bending fatigue test, we has studied the failure mechanism for various conditions and parameters, such as bending strain, fatigue area, film thickness, and lateral dimensions. Moreover, various methods for improving the bending reliability have been developed based on the failure mechanism. Nanostructures such as holes, pores, wires and composites of nanoparticles and nanotubes have been suggested for better reliability. Flexible devices were also investigated to find the potential failures initiated by complex structures under bending fatigue strain. In this review, the recent advances in test methodology, mechanism studies, and practical applications are introduced. Additionally, perspectives including the future advance to stretchable electronics are discussed based on the current achievements in research.

Reliability Issues and Solutions in Flexible Electronics Under Mechanical Fatigue

NASA Astrophysics Data System (ADS)

Yi, Seol-Min; Choi, In-Suk; Kim, Byoung-Joon; Joo, Young-Chang

2018-03-01

Flexible devices are of significant interest due to their potential expansion of the application of smart devices into various fields, such as energy harvesting, biological applications and consumer electronics. Due to the mechanically dynamic operations of flexible electronics, their mechanical reliability must be thoroughly investigated to understand their failure mechanisms and lifetimes. Reliability issue caused by bending fatigue, one of the typical operational limitations of flexible electronics, has been studied using various test methodologies; however, electromechanical evaluations which are essential to assess the reliability of electronic devices for flexible applications had not been investigated because the testing method was not established. By employing the in situ bending fatigue test, we has studied the failure mechanism for various conditions and parameters, such as bending strain, fatigue area, film thickness, and lateral dimensions. Moreover, various methods for improving the bending reliability have been developed based on the failure mechanism. Nanostructures such as holes, pores, wires and composites of nanoparticles and nanotubes have been suggested for better reliability. Flexible devices were also investigated to find the potential failures initiated by complex structures under bending fatigue strain. In this review, the recent advances in test methodology, mechanism studies, and practical applications are introduced. Additionally, perspectives including the future advance to stretchable electronics are discussed based on the current achievements in research.

Electro-Thermal Simulation Studies of SiC Junction Diodes Containing Screw Dislocations Under High Reverse-Bias Operation

NASA Technical Reports Server (NTRS)

Joshi, R. P.

2001-01-01

The objective of this work was to conduct a modeling study of SiC P-N junction diodes operating under high reverse biased conditions. Analytical models and numerical simulation capabilities were to be developed for self-consistent electro-thermal analysis of the diode current-voltage (I-V) characteristics. Data from GRC indicate that screw dislocations are unavoidable in large area SiC devices, and lead to changes in the SiC diode electrical response characteristics under high field conditions. For example, device instability and failures linked to internal current filamentation have been observed. The physical origin of these processes is not well understood, and quantitative projections of the electrical behavior under high field and temperature conditions are lacking. Thermal calculations for SiC devices have not been reported in the literature either. So estimates or projections of peak device temperatures and power limitations do not exist. This numerical study and simulation analysis was aimed at resolving some of the above issues. The following tasks were successfully accomplished: (1) Development of physically based models using one- and two-dimensional drift-diffusion theory for the transport behavior and I-V characteristics; (2) One- and two-dimensional heat flow to account for internal device heating. This led to calculations of the internal temperature profiles, which in turn, were used to update the electrical transport parameters for a self-consistent analysis. The temperature profiles and the peak values were thus obtainable for a given device operating condition; (3) Inclusion of traps assumed to model the presence of internal screw dislocations running along the longitudinal direction; (4) Predictions of the operating characteristics with and without heating as a function of applied bias with and without traps. Both one and two-dimensional cases were implemented; (5) Assessment of device stability based on the operating characteristics. The presence of internal non-uniformities, particularly filamentary structures, was probed and demonstrated; (6) Cause and physical origins of filamentary behavior and unstable I-V characteristics were made transparent; (7) It was demonstrated that diodes containing defects would be more prone to thermal breakdown associated with the temperature dependent decrease in the thermal conductivity; and (8) Finally, negative differential resistance (S-shaped NDR) which can potential lead to device instability and filamentary behavior was shown to occur for diodes containing a line of defects such as could be associated with a screw dislocation line.

Healing of voids in the aluminum metallization of integrated circuit chips

NASA Technical Reports Server (NTRS)

Cuddihy, Edward F.; Lawton, Russell A.; Gavin, Thomas R.

1990-01-01

The thermal stability of GaAs modulation-doped field effect transistors (MODFETs) is evaluated in order to identify failure mechanisms and validate the reliability of these devices. The transistors were exposed to thermal step-stress and characterized at ambient temperatures to indicate device reliability, especially that of the transistor ohmic contacts with and without molybdenum diffusion barriers. The devices without molybdenum exhibited important transconductance deterioration. MODFETs with molybdenum diffusion barriers were tolerant to temperatures above 300 C. This tolerance indicates that thermally activated failure mechanisms are slow at operational temperatures. Therefore, high-reliability MODFET-based circuits are possible.

Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

NASA Astrophysics Data System (ADS)

Javvaji, Brahmanandam; Raha, S.; Mahapatra, D. Roy

2017-02-01

Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

The social comfort of wearable technology and gestural interaction.

PubMed

Dunne, Lucy E; Profita, Halley; Zeagler, Clint; Clawson, James; Gilliland, Scott; Do, Ellen Yi-Luen; Budd, Jim

2014-01-01

The "wearability" of wearable technology addresses the factors that affect the degree of comfort the wearer experiences while wearing a device, including physical, psychological, and social aspects. While the physical and psychological aspects of wearing technology have been investigated since early in the development of the field of wearable computing, the social aspects of wearability have been less fully-explored. As wearable technology becomes increasingly common on the commercial market, social wearability is becoming an ever-more-important variable contributing to the success or failure of new products. Here we present an analysis of social aspects of wearability within the context of the greater understanding of wearability in wearable technology, and focus on selected theoretical frameworks for understanding how wearable products are perceived and evaluated in a social context. Qualitative results from a study of social acceptability of on-body interactions are presented as a case study of social wearability.

More than wishful thinking

NASA Astrophysics Data System (ADS)

Barnes, Cris W.

2009-05-01

The great vision of fusion power - harnessing the energy source of the stars for the good of people on Earth - is and has always been a highly attractive one. The history of fusion research is full of interesting tales, from its discovery to the recent completion of the US National Ignition Facility (NIF), now the world's largest laser (see Physics World March p7). Unfortunately, a new popular account of this history, Sun in a Bottle, mostly retells old stories of notable fusion failures, from mysterious early devices in Argentina through the cold-fusion debacle of the late 1980s. As a scientist who has devoted his career to plasma physics and fusion, I am - at least according to author Charles Seife - part of a community of researchers "unable to rid themselves of their intemperate self-deception". Having read it, I appear to be faced with a choice: am I a fraud or an incompetent?

Biventricular support with the Jarvik 2000 axial flow pump: a feasibility study.

PubMed

Radovancevic, Branislav; Gregoric, Igor D; Tamez, Daniel; Vrtovec, Bojan; Tuzun, Egemen; Chee, Hyun Keun; Moore, Sheila; Jarvik, Robert K; Frazier, O H

2003-01-01

Patients with congestive heart failure who are supported with a left ventricular assist device (LVAD) may experience right ventricular dysfunction or failure that requires support with a right ventricular assist device (RVAD). To determine the feasibility of using a clinically available axial flow ventricular assist device as an RVAD, we implanted Jarvik 2000 pumps in the left ventricle and right atrium of two Corriente crossbred calves (approximately 100 kg each) by way of a left thoracotomy and then analyzed the hemodynamic effects in the mechanically fibrillated heart at various LVAD and RVAD speeds. Right atrial implantation of the device required no modification of either the device or the surgical technique used for left ventricular implantation. Satisfactory biventricular support was achieved during fibrillation as evidenced by an increase in mean aortic pressure from 34 mm Hg with the pumps off to 78 mm Hg with the pumps generating a flow rate of 4.8 L/min. These results indicate that the Jarvik 2000 pump, which can provide chronic circulatory support and can be powered by external batteries, is a feasible option for right ventricular support after LVAD implantation and is capable of completely supporting the circulation in patients with global heart failure.

Performance of Noninvasive Assessment in the Diagnosis of Right Heart Failure After Left Ventricular Assist Device.

PubMed

Joly, Joanna M; El-Dabh, Ashraf; Marshell, Ramey; Chatterjee, Arka; Smith, Michelle G; Tresler, Margaret; Kirklin, James K; Acharya, Deepak; Rajapreyar, Indranee N; Tallaj, José A; Pamboukian, Salpy V

2018-06-01

Right heart failure (RHF) after left ventricular assist device (LVAD) is associated with poor outcomes. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) defines RHF as elevated right atrial pressure (RAP) plus venous congestion. The purpose of this study was to examine the diagnostic performance of the noninvasive INTERMACS criteria using RAP as the gold standard. We analyzed 108 patients with LVAD who underwent 341 right heart catheterizations (RHC) between January 1, 2006, and December 31, 2013. Physical exam, echocardiography, and laboratory data at the time of RHC were collected. Conventional two-by-two tables were used and missing data were excluded. The noninvasive INTERMACS definition of RHF is 32% sensitive (95% CI, 0.21-0.44) and 97% specific (95% CI, 0.95-0.99) for identifying elevated RAP. Clinical assessment failed to identify two-thirds of LVAD patients with RAP > 16 mm Hg. More than half of patients with elevated RAP did not have venous congestion, which may represent a physiologic opportunity to mitigate the progression of disease before end-organ damage occurs. One-quarter of patients who met the noninvasive definition of RHF did not actually have elevated RAP, potentially exposing patients to unnecessary therapies. In practice, if any component of the INTERMACS definition is present or equivocal, our data suggest RHC is warranted to establish the diagnosis.

75 FR 17093 - Neurological and Physical Medicine Devices; Designation of Special Controls for Certain Class II...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-05

... [Docket No. FDA-2009-N-0493] RIN 0910-ZA37 Neurological and Physical Medicine Devices; Designation of... proposing to amend certain neurological device and physical medicine device regulations to establish special..., FDA is proposing to amend the physical medicine devices regulation at Sec. 890.5850 (21 CFR 890.5850...

Institutional Cost Comparison Between Heart Transplants and Left Ventricular Assist Device Implantations.

PubMed

Chimanji, Neeraj; Kilic, Arman; Hasan, Ayesha; Higgins, Robert S D; Whitson, Bryan A; Kilic, Ahmet

2016-12-01

Increased numbers of end-stage heart failure patients and improved technology have led to increased use of left ventricular assist devices as a viable alternative to heart transplants. Given the current economic climate, we compared costs of heart transplant versus device placement. Medical records of patients who received heart transplants or left ventricular assist devices were cross-referenced with institutional financial data. The device cohort was limited to those receiving durable (not temporary) devices. Index admission, 1-year readmission, and overall 1-year charges were compared using standard statistical methods. Of 184 identified patients with end-stage heart failure surgical therapy, 121 received left ventricular assist devices, 43 had heart transplants, and 20 received left ventricular assist devices as bridge to heart transplant; these latter patients were excluded from our analyses. At index admission, mean charges were $863 433 ± $398 427 for device patients and $725 877 ± $488 685 for transplant patients (P = .05). One-year mean readmission rates were similar (4.65/transplant patient and 4.53/device patient; P = .94), with corresponding 1-year survival rates of 87.8% and 78.0% (P = .04). Total readmission charges during year 1 were $169 732 ± $242 366 for device patients and $201 682 ± $297 565 for transplant patients (P = .08), with corresponding overall charges at 1 year of $1 029 732 ± $450 498 and $927 559 ± $562 404 (P = .49). During the first year, heart transplant and left ventricular assist device placement have similar costs. Initial index admission costs seem to favor heart transplant, with device pump costs accounting for some of the difference. From a 1-year survival perspective, heart transplant may be more effective; however, with lack of suitable donors, left ventricular assist devices are valuable in the armamentarium of advanced heart failure surgical options.

Device therapy in heart failure with reduced ejection fraction-cardiac resynchronization therapy and more.

PubMed

Duncker, D; Veltmann, C

2018-05-09

In patients with heart failure with reduced ejection fraction (HFrEF), optimal medical treatment includes beta-blockers, ACE inhibitors/angiotensinreceptor-neprilysin inhibitors (ARNI), mineralocorticoid receptor antagonists, and ivabradine when indicated. In device therapy of HFrEF, implantable cardioverter-defibrillators and cardiac resynchronization therapy (CRT) have been established for many years. CRT is the therapy of choice (class I indication) in symptomatic patients with HFrEF and a broad QRS complex with a left bundle branch block (LBBB) morphology. However, the vast majority of heart failure patients show a narrow QRS complex or a non-LBBB morphology. These patients are not candidates for CRT and alternative electrical therapies such as baroreflex activation therapy (BAT) and cardiac contractility modulation (CCM) may be considered. BAT modulates vegetative dysregulation in heart failure. CCM improves contractility, functional capacity, and symptoms. Although a broad data set is available for BAT and CCM, mortality data are still lacking for both methods. This article provides an overview of the device-based therapeutic options for patients with HFrEF.

Nanoscale effects on the thermal and mechanical properties of AlGaAs/GaAs quantum well laser diodes: influence on the catastrophic optical damage

NASA Astrophysics Data System (ADS)

Souto, Jorge; Pura, José Luis; Jiménez, Juan

2017-06-01

In this work we study the catastrophic optical damage (COD) of graded-index separate confinement heterostructure quantum well (QW) laser diodes based on AlGaAs/GaAs. The emphasis is placed on the impact that the nanoscale physical properties have on the operation and degradation of the active layers of these devices. When these laser diodes run in continuous-wave mode with high internal optical power densities, the QW and guide layers can experiment very intense local heating phenomena that lead to device failure. A thermo-mechanical model has been set up to study the mechanism of degradation. This model has been solved by applying finite element methods. A variety of physical factors related to the materials properties, which play a paramount role in the laser degradation process, have been considered. Among these, the reduced thicknesses of the QW and the guides lead to thermal conductivities smaller than the bulk figures, which are further reduced as extended defects develop in these layers. This results in a progressively deteriorating thermal management in the device. To the best of our knowledge, this model for laser diodes is the first one to have taken into account low scale mechanical effects that result in enhanced strengths in the structural layers. Moreover, the consequences of these conflicting size-dependent properties on the thermo-mechanical behaviour on the route to COD are examined. Subsequently, this approach opens the possibility of taking advantage of these properties in order to design robust diode lasers (or other types of power devices) in a controlled manner.

Research on fault characteristics about switching component failures for distribution electronic power transformers

NASA Astrophysics Data System (ADS)

Sang, Z. X.; Huang, J. Q.; Yan, J.; Du, Z.; Xu, Q. S.; Lei, H.; Zhou, S. X.; Wang, S. C.

2017-11-01

The protection is an essential part for power device, especially for those in power grid, as the failure may cost great losses to the society. A study on the voltage and current abnormality in the power electronic devices in Distribution Electronic Power Transformer (D-EPT) during the failures on switching components is presented, as well as the operational principles for 10 kV rectifier, 10 kV/400 V DC-DC converter and 400 V inverter in D-EPT. Derived from the discussion on the effects of voltage and current distortion, the fault characteristics as well as a fault diagnosis method for D-EPT are introduced.

Improving hemodynamics of cardiovascular system under a novel intraventricular assist device support via modeling and simulations.

PubMed

Zhu, Shidong; Luo, Lin; Yang, Bibo; Li, Xinghui; Wang, Xiaohao

2017-12-01

Ventricular assist devices (LVADs) are increasingly recognized for supporting blood circulation in heart failure patients who are non-transplant eligible. Because of its volume, the traditional pulsatile device is not easy to implant intracorporeally. Continuous flow LVADs (CF-LVADs) reduce arterial pulsatility and only offer continuous flow, which is different from physiological flow, and may cause long-term complications in the cardiovascular system. The aim of this study was to design a new pulsatile assist device that overcomes this disadvantage, and to test this device in the cardiovascular system. Firstly, the input and output characteristics of the new device were tested in a simple cardiovascular mock system. A detailed mathematical model was established by fitting the experimental data. Secondly, the model was tested in four pathological cases, and was simulated and coupled with a fifth-order cardiovascular system and a new device model using Matlab software. Using assistance of the new device, we demonstrated that the left ventricle pressure, aortic pressure, and aortic flow of heart failure patients improved to the levels of a healthy individual. Especially, in state IV level heart failure patients, the systolic blood pressure increased from 81.34 mmHg to 132.1 mmHg, whereas the diastolic blood pressure increased from 54.28 mmHg to 78.7 mmHg. Cardiac output increased from 3.21 L/min to 5.16 L/min. The newly-developed assist device not only provided a physiological flow that was similar to healthy individuals, but also effectively improved the ability of the pathological ventricular volume. Finally, the effects of the new device on other hemodynamic parameters are discussed.

Transcatheter Interatrial Shunt Device for the Treatment of Heart Failure: Rationale and Design of the Randomized Trial to REDUCE Elevated Left Atrial Pressure in Heart Failure (REDUCE LAP-HF I).

PubMed

Feldman, Ted; Komtebedde, Jan; Burkhoff, Daniel; Massaro, Joseph; Maurer, Mathew S; Leon, Martin B; Kaye, David; Silvestry, Frank E; Cleland, John G F; Kitzman, Dalane; Kubo, Spencer H; Van Veldhuisen, Dirk J; Kleber, Franz; Trochu, Jean-Noël; Auricchio, Angelo; Gustafsson, Finn; Hasenfuβ, Gerd; Ponikowski, Piotr; Filippatos, Gerasimos; Mauri, Laura; Shah, Sanjiv J

2016-07-01

Heart failure with preserved ejection fraction (HFpEF), a major public health problem with high morbidity and mortality rates, remains difficult to manage because of a lack of effective treatment options. Although HFpEF is a heterogeneous clinical syndrome, elevated left atrial pressure-either at rest or with exertion-is a common factor among all forms of HFpEF and one of the primary reasons for dyspnea and exercise intolerance in these patients. On the basis of clinical experience with congenital interatrial shunts in mitral stenosis, it has been hypothesized that the creation of a left-to-right interatrial shunt to decompress the left atrium (without compromising left ventricular filling or forward cardiac output) is a rational, nonpharmacological strategy for alleviating symptoms in patients with HFpEF. A novel transcatheter interatrial shunt device has been developed and evaluated in patients with HFpEF in single-arm, nonblinded clinical trials. These studies have demonstrated the safety and potential efficacy of the device. However, a randomized, placebo-controlled evaluation of the device is required to further evaluate its safety and efficacy in patients with HFpEF. In this article, we give the rationale for a therapeutic transcatheter interatrial shunt device in HFpEF, and we describe the design of REDUCE Elevated Left Atrial Pressure in Heart Failure (REDUCE LAP-HF I), the first randomized controlled trial of a device-based therapy to reduce left atrial pressure in HFpEF. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02600234. © 2016 American Heart Association, Inc.

[Artificial organs].

PubMed

Raguin, Thibaut; Dupret-Bories, Agnès; Debry, Christian

2017-01-01

Research has been fighting against organ failure and shortage of donations by supplying artificial organs for many years. With the raise of new technologies, tissue engineering and regenerative medicine, many organs can benefit of an artificial equivalent: thanks to retinal implants some blind people can visualize stimuli, an artificial heart can be proposed in case of cardiac failure while awaiting for a heart transplant, artificial larynx enables laryngectomy patients to an almost normal life, while the diabetic can get a glycemic self-regulation controlled by smartphones with an artificial device. Dialysis devices become portable, as well as the oxygenation systems for terminal respiratory failure. Bright prospects are being explored or might emerge in a near future. However, the retrospective assessment of putative side effects is not yet sufficient. Finally, the cost of these new devices is significant even if the advent of three dimensional printers may reduce it. © 2017 médecine/sciences – Inserm.

40 CFR 240.209-3 - Recommended procedures: Operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operation during such emergency situations as power failure, air or water supply failure, equipment... devices such as hard hats, gloves, safety glasses, and footwear should be provided for facility employees...

Can the Seattle heart failure model be used to risk-stratify heart failure patients for potential left ventricular assist device therapy?

PubMed

Levy, Wayne C; Mozaffarian, Dariush; Linker, David T; Farrar, David J; Miller, Leslie W

2009-03-01

According to results of the REMATCH trial, left ventricular assist device therapy in patients with severe heart failure has resulted in a 48% reduction in mortality. A decision tool will be necessary to aid in the selection of patients for destination left ventricular assist devices (LVADs) as the technology progresses for implantation in ambulatory Stage D heart failure patients. The purpose of this analysis was to determine whether the Seattle Heart Failure Model (SHFM) can be used to risk-stratify heart failure patients for potential LVAD therapy. The SHFM was applied to REMATCH patients with the prospective addition of inotropic agents and intra-aortic balloon pump (IABP) +/- ventilator. The SHFM was highly predictive of survival (p = 0.0004). One-year SHFM-predicted survival was similar to actual survival for both the REMATCH medical (30% vs 28%) and LVAD (49% vs 52%) groups. The estimated 1-year survival with medical therapy for patients in REMATCH was 30 +/- 21%, but with a range of 0% to 74%. The 1- and 2-year estimated survival was

Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction

PubMed Central

Sugimoto, Mitsuru; Takagi, Tadayuki; Suzuki, Rei; Konno, Naoki; Asama, Hiroyuki; Watanabe, Ko; Nakamura, Jun; Kikuchi, Hitomi; Waragai, Yuichi; Takasumi, Mika; Sato, Yuki; Hikichi, Takuto; Ohira, Hiromasa

2017-01-01

AIM To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents (SEMSs). METHODS This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography (ERCP) procedures between the two groups. RESULTS The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices (ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve (sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. CONCLUSION A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement. PMID:28974893

Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction.

PubMed

Sugimoto, Mitsuru; Takagi, Tadayuki; Suzuki, Rei; Konno, Naoki; Asama, Hiroyuki; Watanabe, Ko; Nakamura, Jun; Kikuchi, Hitomi; Waragai, Yuichi; Takasumi, Mika; Sato, Yuki; Hikichi, Takuto; Ohira, Hiromasa

2017-09-14

To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents (SEMSs). This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography (ERCP) procedures between the two groups. The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices (ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve (sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

Efficacy of intrathoracic impedance and remote monitoring in patients with an implantable device after the 2011 great East Japan earthquake.

PubMed

Suzuki, Hitoshi; Yamada, Shinya; Kamiyama, Yoshiyuki; Takeishi, Yasuchika

2014-01-01

Several studies have revealed that stress after catastrophic disasters can trigger cardiovascular events, however, little is known about its association with the occurrence of heart failure in past earthquakes. The objective of the present study was to determine whether the Great East Japan Earthquake on March 11, 2011, increased the incidence of worsening heart failure in chronic heart failure (CHF) patients with implantable devices. Furthermore, we examined whether intrathoracic impedance using remote monitoring was effective for the management of CHF.We enrolled 44 CHF patients (32 males, mean age 63 ± 12 years) with implantable devices that can check intrathoracic impedance using remote monitoring. We defined the worsening heart failure as accumulated impedance under reference impedance exceeding 60 ohms-days (fluid index threshold), and compared the incidence of worsening heart failure and arrhythmic events 30 days before and after March 11.Within the 30 days after March 11, 10 patients exceeded the threshold compared with only 2 patients in the preceding 30 days (P < 0.05). Although 9 patients using remote monitoring among the 10 patients with threshold crossings were not hospitalized, one patient without the system was hospitalized due to acute decompensated heart failure. On the contrary, arrhythmic events did not change between before and after March 11.Our results suggest that earthquake-induced stress causes an increased risk of worsening heart failure without changes in arrhythmia. Furthermore, intrathoracic impedance using remote monitoring may be a useful tool for the management of CHF in catastrophic disasters.

Shear-induced mechanical failure of β -G a2O3 from quantum mechanics simulations

NASA Astrophysics Data System (ADS)

An, Qi; Li, Guodong

2017-10-01

Monoclinic gallium oxide (β -G a2O3 ) has important applications in power devices and deep UV optoelectronic devices because of such novel properties as a wide band gap, high breakdown electric field, and a wide range of n -type doping conductivity. However, the intrinsic failure mechanisms of β -G a2O3 remain unknown, which limits the fabrication and packaging of β -G a2O3 -based electronic devices. Here we used density-functional theory at the Perdew-Burke-Ernzerhof level to examine the shear-induced failure mechanisms of β -G a2O3 along various plausible slip systems. We found that the (001 )/〈010 〉 slip system has the lowest ideal shear strength of 3.8 GPa among five plausible slip systems, suggesting that (001 )/〈010 〉 is the most plausible activated slip system. This slip leads to an intrinsic failure mechanism arising from breaking the longest Ga-O bond between octahedral Ga and fourfold-coordinated O. Then we identified the same failure mechanism of β -G a2O3 under biaxial shear deformation that mimics indentation stress conditions. Finally, the general stacking fault energy (SFE) surface is calculated for the (001) surface from which we concluded that there is no intrinsic stacking fault structure for β -G a2O3 . The deformation modes and SFE calculations are essential to understand the intrinsic mechanical processes of this semiconductor material, which provides insightful guidance for designing high-performance semiconductor devices.

Synthetic devices for reconstructive surgery of the cruciate ligaments: a systematic review.

PubMed

Batty, Lachlan M; Norsworthy, Cameron J; Lash, Nicholas J; Wasiak, Jason; Richmond, Anneka K; Feller, Julian A

2015-05-01

The role of synthetic devices in the management of the cruciate ligament-injured knee remains controversial. The aim of this systematic review was to assess the safety and efficacy of synthetic devices in cruciate ligament surgery. A systematic review of the electronic databases Medline, Embase, and The Cochrane Library (issue 1, 2014) on January 13, 2014, was performed to identify controlled and uncontrolled trials. Trials that assessed the safety and efficacy of synthetic devices for cruciate ligament surgery were included. The main variables assessed included rates of failure, revision, and noninfective effusion and synovitis. Patient-reported outcome assessments and complications were also assessed where reported. From 511 records screened, we included 85 articles published between 1985 and 2013 reporting on 6 synthetic devices (ligament augmentation and reconstruction system [Ligament Augmentation and Reconstruction System (LARS; Surgical Implants and Devices, Arc-sur-Tille, France)]; Leeds-Keio [Xiros (formerly Neoligaments), Leeds, England]; Kennedy ligament augmentation device [3M, St Paul, MN]; Dacron [Stryker, Kalamazoo, MI]; Gore-Tex [W.L. Gore and Associates, Flagstaff, AZ]; and Trevira [Telos (limited liability company), Marburg, Germany]). The heterogeneity of the included studies precluded meta-analysis. The results were analyzed by device and then type of reconstruction (anterior cruciate ligament [ACL]/posterior cruciate ligament [PCL]/combined ACL and PCL). The lowest cumulative rates of failure were seen with the LARS device (2.6% for ACL and 1% for PCL surgery). The highest failure rate was seen in the Dacron ACL group (cumulative rate, 33.6%). Rates of noninfective synovitis and effusion ranged from 0.2% in the LARS ACL group to 27.6% in the Gore-Tex ACL group. Revision rates ranged from 2.6% (LARS) to 11.8% (Trevira-Hochfest; Telos). Recent designs, specifically the LARS, showed good improvement in the outcome scores. The mean preoperative and postoperative Lysholm knee scores were 54 and 88, respectively; the mean preoperative and postoperative Tegner activity scale scores were 3.3 and 6, respectively. Preliminary results for newer-generation devices, specifically the LARS, show lower reported rates of failure, revision, and sterile effusion/synovitis when compared with older devices. Level IV, systematic review of Level II through IV studies. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

78 FR 79300 - Cardiovascular Devices; Reclassification of Intra-Aortic Balloon and Control Systems for Acute...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-30

... balloon and control system (IABP) devices when indicated for acute coronary syndrome, cardiac and non... and non-cardiac surgery, or complications of heart failure. The special controls for this device are.... FDA-2013-N-0581] Cardiovascular Devices; Reclassification of Intra-Aortic Balloon and Control Systems...

Physical nature of longevity of light actinides in dynamic failure phenomenon

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

Uchaev, A. Ya., E-mail: uchaev@expd.vniief.ru; Punin, V. T.; Selchenkova, N. I.

It is shown in this work that the physical nature of the longevity of light actinides under extreme conditions in a range of nonequilibrium states of t ∼ 10{sup –6}–10{sup –10} s is determined by the time needed for the formation of a critical concentration of a cascade of failure centers, which changes connectivity of the body. These centers form a percolation cluster. The longevity is composed of waiting time t{sub w} for the appearance of failure centers and clusterization time t{sub c} of cascade of failure centers, when connectivity in the system of failure centers and the percolation clustermore » arise. A unique mechanism of the dynamic failure process, a unique order parameter, and an equal dimensionality of the space in which the process occurs determine the physical nature of the longevity of metals, including fissionable materials.« less

The Role of Computational Modeling and Simulation in the Total Product Life Cycle of Peripheral Vascular Devices

PubMed Central

Morrison, Tina M.; Dreher, Maureen L.; Nagaraja, Srinidhi; Angelone, Leonardo M.; Kainz, Wolfgang

2018-01-01

The total product life cycle (TPLC) of medical devices has been defined by four stages: discovery and ideation, regulatory decision, product launch, and postmarket monitoring. Manufacturers of medical devices intended for use in the peripheral vasculature, such as stents, inferior vena cava (IVC) filters, and stent-grafts, mainly use computational modeling and simulation (CM&S) to aid device development and design optimization, supplement bench testing for regulatory decisions, and assess postmarket changes or failures. For example, computational solid mechanics and fluid dynamics enable the investigation of design limitations in the ideation stage. To supplement bench data in regulatory submissions, manufactures can evaluate the effects of anatomical characteristics and expected in vivo loading environment on device performance. Manufacturers might also harness CM&S to aid root-cause analyses that are necessary when failures occur postmarket, when the device is exposed to broad clinical use. Once identified, CM&S tools can then be used for redesign to address the failure mode and re-establish the performance profile with the appropriate models. The Center for Devices and Radiological Health (CDRH) wants to advance the use of CM&S for medical devices and supports the development of virtual physiological patients, clinical trial simulations, and personalized medicine. Thus, the purpose of this paper is to describe specific examples of how CM&S is currently used to support regulatory submissions at different phases of the TPLC and to present some of the stakeholder-led initiatives for advancing CM&S for regulatory decision-making. PMID:29479395

The Role of Computational Modeling and Simulation in the Total Product Life Cycle of Peripheral Vascular Devices.

PubMed

Morrison, Tina M; Dreher, Maureen L; Nagaraja, Srinidhi; Angelone, Leonardo M; Kainz, Wolfgang

2017-01-01

The total product life cycle (TPLC) of medical devices has been defined by four stages: discovery and ideation, regulatory decision, product launch, and postmarket monitoring. Manufacturers of medical devices intended for use in the peripheral vasculature, such as stents, inferior vena cava (IVC) filters, and stent-grafts, mainly use computational modeling and simulation (CM&S) to aid device development and design optimization, supplement bench testing for regulatory decisions, and assess postmarket changes or failures. For example, computational solid mechanics and fluid dynamics enable the investigation of design limitations in the ideation stage. To supplement bench data in regulatory submissions, manufactures can evaluate the effects of anatomical characteristics and expected in vivo loading environment on device performance. Manufacturers might also harness CM&S to aid root-cause analyses that are necessary when failures occur postmarket, when the device is exposed to broad clinical use. Once identified, CM&S tools can then be used for redesign to address the failure mode and re-establish the performance profile with the appropriate models. The Center for Devices and Radiological Health (CDRH) wants to advance the use of CM&S for medical devices and supports the development of virtual physiological patients, clinical trial simulations, and personalized medicine. Thus, the purpose of this paper is to describe specific examples of how CM&S is currently used to support regulatory submissions at different phases of the TPLC and to present some of the stakeholder-led initiatives for advancing CM&S for regulatory decision-making.

Mechanical Circulatory Support of the Right Ventricle for Adult and Pediatric Patients With Heart Failure.

PubMed

Chopski, Steven G; Murad, Nohra M; Fox, Carson S; Stevens, Randy M; Throckmorton, Amy L

2018-05-10

The clinical implementation of mechanical circulatory assistance for a significantly dysfunctional or failing left ventricle as a bridge-to-transplant or bridge-to-recovery is on the rise. Thousands of patients with left-sided heart failure are readily benefitting from these life-saving technologies, and left ventricular failure often leads to severe right ventricular dysfunction or failure. Right ventricular failure (RVF) has a high rate of mortality caused by the risk of multisystem organ failure and prolonged hospitalization for patients after treatment. The use of a blood pump to support the left ventricle also typically results in an increase in right ventricular preload and may impair right ventricular contractility during left ventricular unloading. Patients with RVF might also suffer from severe pulmonary dysfunction, cardiac defects, congenital heart disease states, or a heterogeneity of cardiophysiologic challenges because of symptomatic congestive heart failure. Thus, the uniqueness and complexity of RVF is emerging as a new domain of significant clinical interest that motivates the development of right ventricular assist devices. In this review, we present the current state-of-the-art for clinically used blood pumps to support adults and pediatric patients with right ventricular dysfunction or failure concomitant with left ventricular failure. New innovative devices specifically for RVF are also highlighted. There continues to be a compelling need for novel treatment options to support patients with significant right heart dysfunction or failure.

Advances in bioartificial liver assist devices.

PubMed

Patzer, J F

2001-11-01

Rapid advances in development of bioartificial liver assist devices (BLADs) are exciting clinical interest in the application of BLAD technology for support of patients with acute liver failure. Four devices (Circe Biomedical HepatAssist, Vitagen ELAD, Gerlach BELS, and Excorp Medical BLSS) that rely on hepatocytes cultured in hollow-fiber membrane technology are currently in various stages of clinical evaluation. Several alternative approaches for culture and perfusion of hepatocytes have been evaluated in preclinical, large animal models of liver failure, or at a laboratory scale. Engineering design issues with respect to xenotransplantation, BLAD perfusion, hepatocyte functionality and culture maintenance, and ultimate distribution of a BLAD to a clinical site are delineated.

Efficient Actor Recovery Paradigm for Wireless Sensor and Actor Networks

PubMed Central

Mahjoub, Reem K.; Elleithy, Khaled

2017-01-01

The actor nodes are the spine of wireless sensor and actor networks (WSANs) that collaborate to perform a specific task in an unverified and uneven environment. Thus, there is a possibility of high failure rate in such unfriendly scenarios due to several factors such as power consumption of devices, electronic circuit failure, software errors in nodes or physical impairment of the actor nodes and inter-actor connectivity problem. Therefore, it is extremely important to discover the failure of a cut-vertex actor and network-disjoint in order to improve the Quality-of-Service (QoS). In this paper, we propose an Efficient Actor Recovery (EAR) paradigm to guarantee the contention-free traffic-forwarding capacity. The EAR paradigm consists of a Node Monitoring and Critical Node Detection (NMCND) algorithm that monitors the activities of the nodes to determine the critical node. In addition, it replaces the critical node with backup node prior to complete node-failure which helps balancing the network performance. The packets are handled using Network Integration and Message Forwarding (NIMF) algorithm that determines the source of forwarding the packets; either from actor or sensor. This decision-making capability of the algorithm controls the packet forwarding rate to maintain the network for a longer time. Furthermore, for handling the proper routing strategy, Priority-Based Routing for Node Failure Avoidance (PRNFA) algorithm is deployed to decide the priority of the packets to be forwarded based on the significance of information available in the packet. To validate the effectiveness of the proposed EAR paradigm, the proposed algorithms were tested using OMNET++ simulation. PMID:28420102

Efficient Actor Recovery Paradigm for Wireless Sensor and Actor Networks.

PubMed

Mahjoub, Reem K; Elleithy, Khaled

2017-04-14

The actor nodes are the spine of wireless sensor and actor networks (WSANs) that collaborate to perform a specific task in an unverified and uneven environment. Thus, there is a possibility of high failure rate in such unfriendly scenarios due to several factors such as power consumption of devices, electronic circuit failure, software errors in nodes or physical impairment of the actor nodes and inter-actor connectivity problem. Therefore, it is extremely important to discover the failure of a cut-vertex actor and network-disjoint in order to improve the Quality-of-Service (QoS). In this paper, we propose an Efficient Actor Recovery (EAR) paradigm to guarantee the contention-free traffic-forwarding capacity. The EAR paradigm consists of a Node Monitoring and Critical Node Detection (NMCND) algorithm that monitors the activities of the nodes to determine the critical node. In addition, it replaces the critical node with backup node prior to complete node-failure which helps balancing the network performance. The packets are handled using Network Integration and Message Forwarding (NIMF) algorithm that determines the source of forwarding the packets; either from actor or sensor. This decision-making capability of the algorithm controls the packet forwarding rate to maintain the network for a longer time. Furthermore, for handling the proper routing strategy, Priority-Based Routing for Node Failure Avoidance (PRNFA) algorithm is deployed to decide the priority of the packets to be forwarded based on the significance of information available in the packet. To validate the effectiveness of the proposed EAR paradigm, the proposed algorithms were tested using OMNET++ simulation.

The strength study of the rotating device driver indexing spatial mechanism

NASA Astrophysics Data System (ADS)

Zakharenkov, N. V.; Kvasov, I. N.

2018-04-01

The indexing spatial mechanisms are widely used in automatic machines. The mechanisms maximum load-bearing capacity measurement is possible based on both the physical and numerical models tests results. The paper deals with the driven disk indexing spatial cam mechanism numerical model at the constant angular cam velocity. The presented mechanism kinematics and geometry parameters and finite element model are analyzed in the SolidWorks design environment. The calculation initial data and missing parameters having been found from the structure analysis were identified. The structure and kinematics analysis revealed the mechanism failures possible reasons. The numerical calculations results showing the structure performance at the contact and bending stresses are represented.

Heart failure in children - overview

MedlinePlus

... heart failure worse Monitor for side effects of medicines your child may be taking ... a safe and effective exercise and activity plan. MEDICINES, SURGERY, AND DEVICES Your child will need to take medicines to treat heart ...

Left ventricular assist devices as destination therapy: a new look at survival.

PubMed

Park, Soon J; Tector, Alfred; Piccioni, William; Raines, Edward; Gelijns, Annetine; Moskowitz, Alan; Rose, Eric; Holman, William; Furukawa, Satoshi; Frazier, O Howard; Dembitsky, Walter

2005-01-01

The REMATCH trial compared the use of left ventricular assist devices with optimal medical management for patients with end-stage heart failure. When the trial met its primary end point criteria in July 2001, left ventricular assist device therapy was shown to significantly improve survival and quality of life. With extended follow-up, 2 critical questions emerge: (1) Did these benefits persist, and (2) did outcomes improve over the course of the trial, given the evolving nature of the technology? We analyzed survival in this randomized trial by using the product-limit method of Kaplan and Meier. Changes in the benefits of therapy were analyzed by examining the effect of the enrollment period. The survival rates for patients receiving left ventricular assist devices (n = 68) versus patients receiving optimal medical management (n = 61) were 52% versus 28% at 1 year and 29% versus 13% at 2 years ( P = .008, log-rank test). As of July 2003, 11 patients were alive on left ventricular assist device support out of a total 16 survivors (including 3 patients receiving optimal medical management who crossed over to left ventricular assist device therapy). There was a significant improvement in survival for left ventricular assist device-supported patients who enrolled during the second half of the trial compared with the first half ( P = .03). The Minnesota Living with Heart Failure scores improved significantly over the course of the trial. The extended follow-up confirms the initial observation that left ventricular assist device therapy renders significant survival and quality-of-life benefits compared with optimal medical management for patients with end-stage heart failure. Furthermore, we observed an improvement in the survival of patients receiving left ventricular assist devices over the course of the trial, suggesting the effect of greater clinical experience.

Improved Photon-Emission-Microscope System

NASA Technical Reports Server (NTRS)

Vu, Duc

2006-01-01

An improved photon-emission-microscope (PEM) instrumentation system has been developed for use in diagnosing failure conditions in semiconductor devices, including complex integrated circuits. This system is designed primarily to image areas that emit photons, at wavelengths from 400 to 1,100 nm, associated with device failures caused by leakage of electric current through SiO2 and other dielectric materials used in multilayer semiconductor structures. In addition, the system is sensitive enough to image areas that emit photons during normal operation.

Understanding the failure mechanisms of microwave bipolar transistors caused by electrostatic discharge

NASA Astrophysics Data System (ADS)

Jin, Liu; Yongguang, Chen; Zhiliang, Tan; Jie, Yang; Xijun, Zhang; Zhenxing, Wang

2011-10-01

Electrostatic discharge (ESD) phenomena involve both electrical and thermal effects, and a direct electrostatic discharge to an electronic device is one of the most severe threats to component reliability. Therefore, the electrical and thermal stability of multifinger microwave bipolar transistors (BJTs) under ESD conditions has been investigated theoretically and experimentally. 100 samples have been tested for multiple pulses until a failure occurred. Meanwhile, the distributions of electric field, current density and lattice temperature have also been analyzed by use of the two-dimensional device simulation tool Medici. There is a good agreement between the simulated results and failure analysis. In the case of a thermal couple, the avalanche current distribution in the fingers is in general spatially unstable and results in the formation of current crowding effects and crystal defects. The experimental results indicate that a collector-base junction is more sensitive to ESD than an emitter-base junction based on the special device structure. When the ESD level increased to 1.3 kV, the collector-base junction has been burnt out first. The analysis has also demonstrated that ESD failures occur generally by upsetting the breakdown voltage of the dielectric or overheating of the aluminum-silicon eutectic. In addition, fatigue phenomena are observed during ESD testing, with devices that still function after repeated low-intensity ESDs but whose performances have been severely degraded.

Perceived success/failure and attributions associated with self-regulatory efficacy to meet physical activity recommendations for women with arthritis.

PubMed

Spink, Kevin S; Brawley, Lawrence R; Gyurcsik, Nancy C

2016-10-01

The relationship between attributional dimensions women assign to the cause of their perceived success or failure at meeting the recommended physical activity dose and self-regulatory efficacy for future physical activity was examined among women with arthritis. Women (N = 117) aged 18-84 years, with self-reported medically-diagnosed arthritis, completed on-line questions in the fall of 2013 assessing endurance physical activity, perceived outcome for meeting the recommended levels of endurance activity, attributions for one's success or failure in meeting the recommendations, and self-regulatory efficacy to schedule/plan endurance activity over the next month. The main theoretically-driven finding revealed that the interaction of the stability dimension with perceived success/failure was significantly related to self-regulatory efficacy for scheduling and planning future physical activity (β = 0.35, p = .002). Outcomes attributed to more versus less stable factors accentuated differences in self-regulatory efficacy beliefs following perceived success and failure at being active. It appears that attributional dimensions were associated with self-regulatory efficacy in women with arthritis. This suggests that rather than objectively observed past mastery experience, women's subjective perceptions and explanations of their past experiences were related to efficacy beliefs, especially following a failure experience.

Experience in cochlear reimplantation. Descriptive study of a 20-year period.

PubMed

Gutiérrez-Salazar, Andrés; Cop, Constanze; Osorio-Acosta, Ángel; Borkoski-Barreiro, Silvia; Falcón-González, Juan C; Ramos-Macías, Ángel

2015-01-01

The cochlear implant is a surgical procedure that has increased substantially, because the paediatric population is diagnosed and implanted early and because there are increased potential indications. This device has the inherent risk of failure in performance, as dies any active medical device, which is the most common cause of implant removal. Our goal was to understand what the causes that produced removal in our series were, and confirm if these conformed to reality as reviewed in the literature. This was a retrospective, descriptive, observational study of 859 cochlear implant surgeries carried out between October 1991 and May 2011. The causes of implant removal were classified according to the European Consensus Statement on Cochlear Implant Failures and Explantations. The reimplantation rate was 6.16% (n=51). The most common reason for removal was technical device failure (45.5%), followed by infection/rejection (23.6%) and upgrade (12.7%). Less common causes: there were 3 cases (5.6%) of electrode misplacement, 2 cases (3.6%) of labyrinthine ossification, 2 (3.6%) as a result of head trauma, 2 (3.6%) from need for nuclear magnetic resonance imaging and 1 case (1.8%) from psychiatric illness. Cochlear reimplantation is a safe procedure, with a low complication rate. In our centre, it reaches an overall rate of 6.16%. Technical device failure remains the most common cause of this procedure, although there is a significant percentage of reimplantation for device update. Copyright © 2014 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

Investigating the origins of high multilevel resistive switching in forming free Ti/TiO2-x-based memory devices through experiments and simulations

NASA Astrophysics Data System (ADS)

Bousoulas, P.; Giannopoulos, I.; Asenov, P.; Karageorgiou, I.; Tsoukalas, D.

2017-03-01

Although multilevel capability is probably the most important property of resistive random access memory (RRAM) technology, it is vulnerable to reliability issues due to the stochastic nature of conducting filament (CF) creation. As a result, the various resistance states cannot be clearly distinguished, which leads to memory capacity failure. In this work, due to the gradual resistance switching pattern of TiO2-x-based RRAM devices, we demonstrate at least six resistance states with distinct memory margin and promising temporal variability. It is shown that the formation of small CFs with high density of oxygen vacancies enhances the uniformity of the switching characteristics in spite of the random nature of the switching effect. Insight into the origin of the gradual resistance modulation mechanisms is gained by the application of a trap-assisted-tunneling model together with numerical simulations of the filament formation physical processes.

Frailty Assessment in Heart Failure: an Overview of the Multi-domain Approach.

PubMed

McDonagh, Julee; Ferguson, Caleb; Newton, Phillip J

2018-02-01

The study aims (1) to provide a contemporary description of frailty assessment in heart failure and (2) to provide an overview of multi-domain frailty assessment in heart failure. Frailty assessment is an important predictive measure for mortality and hospitalisation in individuals with heart failure. To date, there are no frailty assessment instruments validated for use in heart failure. This has resulted in significant heterogeneity between studies regarding the assessment of frailty. The most common frailty assessment instrument used in heart failure is the Frailty Phenotype which focuses on five physical domains of frailty; the appropriateness a purely physical measure of frailty in individuals with heart failure who frequently experience decreased exercise tolerance and shortness of breath is yet to be determined. A limited number of studies have approached frailty assessment using a multi-domain view which may be more clinically relevant in heart failure. There remains a lack of consensus regarding frailty assessment and an absence of a validated instrument in heart failure. Despite this, frailty continues to be assessed frequently, primarily for research purposes, using predominantly physical frailty measures. A more multidimensional view of frailty assessment using a multi-domain approach will likely be more sensitive to identifying at risk patients.

Cyclic and low temperature effects on microcircuits

NASA Technical Reports Server (NTRS)

Weissflug, V. A.; Sisul, E. V.

1977-01-01

Cyclic temperature and low temperature operating life tests, and pre-/post-life device evaluations were used to determine the degrading effects of thermal environments on microcircuit reliability. Low power transistor-transistor-logic gates and linear devices were included in each test group. Device metallization systems included aluminum metallization/aluminum wire, aluminum metallization/gold wire, and gold metallization/gold wire. Fewer than 2% electrical failures were observed during the cyclic and low temperature life tests and the post-life evaluations revealed approximately 2% bond pull failures. Reconstruction of aluminum die metallization was observed in all devices and the severity of the reconstruction appeared to be directly related to the magnitude of the temperature excursion. All types of bonds except the gold/gold bonds were weakened by exposure to repeated cyclic temperature stress.

Radiation effects and mitigation strategies for modern FPGAs

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

Stettler, M. W.; Caffrey, M. P.; Graham, P. S.

2004-01-01

Field Programmable Gate Array devices have become the technology of choice in small volume modern instrumentation and control systems. These devices have always offered significant advantages in flexibility, and recent advances in fabrication have greatly increased logic capacity, substantially increasing the number of applications for this technology. Unfortunately, the increased density (and corresponding shrinkage of process geometry), has made these devices more susceptible to failure due to external radiation. This has been an issue for space based systems for some time, but is now becoming an issue for terrestrial systems in elevated radiation environments and commercial avionics as well. Characterizingmore » the failure modes of Xilinx FPGAs, and developing mitigation strategies is the subject of ongoing research by a consortium of academic, industrial, and governmental laboratories. This paper presents background information of radiation effects and failure modes, as well as current and future mitigation techniques. In particular, the availability of very large FPGA devices, complete with generous amounts of RAM and embedded processor(s), has led to the implementation of complete digital systems on a single device, bringing issues of system reliability and redundancy management to the chip level. Radiation effects on a single FPGA are increasingly likely to have system level consequences, and will need to be addressed in current and future designs.« less

Fault Tree Based Diagnosis with Optimal Test Sequencing for Field Service Engineers

NASA Technical Reports Server (NTRS)

Iverson, David L.; George, Laurence L.; Patterson-Hine, F. A.; Lum, Henry, Jr. (Technical Monitor)

1994-01-01

When field service engineers go to customer sites to service equipment, they want to diagnose and repair failures quickly and cost effectively. Symptoms exhibited by failed equipment frequently suggest several possible causes which require different approaches to diagnosis. This can lead the engineer to follow several fruitless paths in the diagnostic process before they find the actual failure. To assist in this situation, we have developed the Fault Tree Diagnosis and Optimal Test Sequence (FTDOTS) software system that performs automated diagnosis and ranks diagnostic hypotheses based on failure probability and the time or cost required to isolate and repair each failure. FTDOTS first finds a set of possible failures that explain exhibited symptoms by using a fault tree reliability model as a diagnostic knowledge to rank the hypothesized failures based on how likely they are and how long it would take or how much it would cost to isolate and repair them. This ordering suggests an optimal sequence for the field service engineer to investigate the hypothesized failures in order to minimize the time or cost required to accomplish the repair task. Previously, field service personnel would arrive at the customer site and choose which components to investigate based on past experience and service manuals. Using FTDOTS running on a portable computer, they can now enter a set of symptoms and get a list of possible failures ordered in an optimal test sequence to help them in their decisions. If facilities are available, the field engineer can connect the portable computer to the malfunctioning device for automated data gathering. FTDOTS is currently being applied to field service of medical test equipment. The techniques are flexible enough to use for many different types of devices. If a fault tree model of the equipment and information about component failure probabilities and isolation times or costs are available, a diagnostic knowledge base for that device can be developed easily.

Structural Stability Monitoring of a Physical Model Test on an Underground Cavern Group during Deep Excavations Using FBG Sensors.

PubMed

Li, Yong; Wang, Hanpeng; Zhu, Weishen; Li, Shucai; Liu, Jian

2015-08-31

Fiber Bragg Grating (FBG) sensors are comprehensively recognized as a structural stability monitoring device for all kinds of geo-materials by either embedding into or bonding onto the structural entities. The physical model in geotechnical engineering, which could accurately simulate the construction processes and the effects on the stability of underground caverns on the basis of satisfying the similarity principles, is an actual physical entity. Using a physical model test of underground caverns in Shuangjiangkou Hydropower Station, FBG sensors were used to determine how to model the small displacements of some key monitoring points in the large-scale physical model during excavation. In the process of building the test specimen, it is most successful to embed FBG sensors in the physical model through making an opening and adding some quick-set silicon. The experimental results show that the FBG sensor has higher measuring accuracy than other conventional sensors like electrical resistance strain gages and extensometers. The experimental results are also in good agreement with the numerical simulation results. In conclusion, FBG sensors could effectively measure small displacements of monitoring points in the whole process of the physical model test. The experimental results reveal the deformation and failure characteristics of the surrounding rock mass and make some guidance for the in situ engineering construction.

Structural Stability Monitoring of a Physical Model Test on an Underground Cavern Group during Deep Excavations Using FBG Sensors

PubMed Central

Li, Yong; Wang, Hanpeng; Zhu, Weishen; Li, Shucai; Liu, Jian

2015-01-01

Fiber Bragg Grating (FBG) sensors are comprehensively recognized as a structural stability monitoring device for all kinds of geo-materials by either embedding into or bonding onto the structural entities. The physical model in geotechnical engineering, which could accurately simulate the construction processes and the effects on the stability of underground caverns on the basis of satisfying the similarity principles, is an actual physical entity. Using a physical model test of underground caverns in Shuangjiangkou Hydropower Station, FBG sensors were used to determine how to model the small displacements of some key monitoring points in the large-scale physical model during excavation. In the process of building the test specimen, it is most successful to embed FBG sensors in the physical model through making an opening and adding some quick-set silicon. The experimental results show that the FBG sensor has higher measuring accuracy than other conventional sensors like electrical resistance strain gages and extensometers. The experimental results are also in good agreement with the numerical simulation results. In conclusion, FBG sensors could effectively measure small displacements of monitoring points in the whole process of the physical model test. The experimental results reveal the deformation and failure characteristics of the surrounding rock mass and make some guidance for the in situ engineering construction. PMID:26404287

Solder Reflow Failures in Electronic Components During Manual Soldering

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander; Greenwell, Chris; Felt, Frederick

2008-01-01

This viewgraph presentation reviews the solder reflow failures in electronic components that occur during manual soldering. It discusses the specifics of manual-soldering-induced failures in plastic devices with internal solder joints. The failure analysis turned up that molten solder had squeezed up to the die surface along the die molding compound interface, and the dice were not protected with glassivation allowing solder to short gate and source to the drain contact. The failure analysis concluded that the parts failed due to overheating during manual soldering.

Physically based DC lifetime model for lead zirconate titanate films

NASA Astrophysics Data System (ADS)

Garten, Lauren M.; Hagiwara, Manabu; Ko, Song Won; Trolier-McKinstry, Susan

2017-09-01

Accurate lifetime predictions for Pb(Zr0.52Ti0.48)O3 thin films are critical for a number of applications, but current reliability models are not consistent with the resistance degradation mechanisms in lead zirconate titanate. In this work, the reliability and lifetime of chemical solution deposited (CSD) and sputtered Pb(Zr0.52Ti0.48)O3 thin films are characterized using highly accelerated lifetime testing (HALT) and leakage current-voltage (I-V) measurements. Temperature dependent HALT results and impedance spectroscopy show activation energies of approximately 1.2 eV for the CSD films and 0.6 eV for the sputtered films. The voltage dependent HALT results are consistent with previous reports, but do not clearly indicate what causes device failure. To understand more about the underlying physical mechanisms leading to degradation, the I-V data are fit to known conduction mechanisms, with Schottky emission having the best-fit and realistic extracted material parameters. Using the Schottky emission equation as a base, a unique model is developed to predict the lifetime under highly accelerated testing conditions based on the physical mechanisms of degradation.

Comparison of effects of extra-thoracic paraaortic counterpulsation to intraaortic balloon pump on circulatory support in acute heart failure.

PubMed

Zhang, Jie-Min; Liu, Xiao-Cheng; Liu, Zhi-Gang; Zhao, Long; Yang, Li; Liu, Tian-Wen; He, Guo-Wei

2015-11-24

Previously designed intra-thoracic paraaortic counterpulsation device has limited stroke volume and may depress the lung to cause complications. The purpose of this study was to evaluate the hemodynamic effects of an extra-thoracic paraaortic counterpulsation device (ETPACD) in comparison to intraaortic balloon pump (IABP) in an animal model with acute heart failure. The acute heart failure model was successfully induced by snaring branch of anterior descending coronary artery in sheep (weighting, 38-50 kg, n = 8). The ETPACD is a single port, 65-ml stroke volume blood chamber designed to be connected to descending aorta through a valveless graft and placed extra-thorax. In comparison, a standard clinical 40-ml IABP was placed in the descending aorta. The hemodynamic indices of both devices were recorded during counterpulsation assistance. Two of the sheep were allowed to survive for 1 week to examine the prolonged effect. Both ETPACD and IABP increased cardiac output with higher effect of ETPACD (13.52 % vs. 8.19 % in IABP, P < 0.05) and on mean diastolic aortic pressure (26.73 % vs. 12.58 % in IABP, P < 0.01). Both ETPACD and IABP also produced a greater reduction in left ventricular end-diastolic pressure (26.77 % vs. 23.08 %, P > 0.05). The ETPACD increased left carotid artery flow more significantly the IABP (18.00 % vs. 9.19 % , P < 0.05). In two of the sheep allowed to survive for 1 week, the device worked well with no complications and there was no thrombus formation in the chamber of ETPACD. This study demonstrated that both ETPACD and IABP provided benefit of circulatory support in acute heart failure with better effect on hemodynamic parameters provided by ETPACD. Therefore, ETPACD with theoretical larger stroke volume may become a promising counterpulsation device for treatment of heart failure.

Da Vinci robot error and failure rates: single institution experience on a single three-arm robot unit of more than 700 consecutive robot-assisted laparoscopic radical prostatectomies.

PubMed

Zorn, Kevin C; Gofrit, Ofer N; Orvieto, Marcelo A; Mikhail, Albert A; Galocy, R Matthew; Shalhav, Arieh L; Zagaja, Gregory P

2007-11-01

Previous reports have suggested that a 2% to 5% device failure rate (FR) be quoted when counseling patients about robot-assisted laparoscopic radical prostatectomy (RLRP). We sought to evaluate our FR on the da Vinci system. Since February 2003, more than 800 RLRPs have been performed at our institution using a single three-armed robotic unit. A prospective database was analyzed to determine the device FR and whether it resulted in case abortion or open conversion. Intuitive Surgical Systems provided data concerning the system's performance, including its fault rate. Error messages were classified as recoverable and non-recoverable faults. Between February 2003 and November 2006, 725 RLRP cases were available for evaluation. There were no intraoperative device failures that resulted in a case conversion. Technical errors resulting in surgeon handicap occurred in 3 cases (0.4%). Four patients (0.5%) had their procedures aborted secondary to system failure at initial set-up prior to patient entrance to the operating room. Data analysis retrieved from the da Vinci console reported on a total of 807 procedures since 2003. Only 4 cases (0.4%) were reported from the Intuitive Surgical database to result in either an aborted or a converted case, which compares favorably with our results. Since the last computer system upgrade (September 2005), the mean recoverable and non-recoverable fault rates per procedure were 0.21 and 0.05, respectively. For all the advanced features the da Vinci system offers, it is surprisingly reliable. Throughout our RLRP experience, device failure resulted in case conversion, procedure abortion, and surgeon handicap in 0, 0.5%, and 0.4% of procedures, respectively. As such, a lowered device FR of 0.5% should be used when counseling patients undergoing RLRP. To avoid futile general anesthesia, a policy should be enforced to ensure that the da Vinci system is completely set up before the patient enters the operating room.

Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison.

PubMed

Avery, Ryan; Day, Kevin; Jokerst, Clinton; Kazui, Toshinobu; Krupinski, Elizabeth; Khalpey, Zain

2017-10-10

Advanced heart failure treated with a left ventricular assist device is associated with a higher risk of right heart failure. Many advanced heart failures patients are treated with an ICD, a relative contraindication to MRI, prior to assist device placement. Given this limitation, left and right ventricular function for patients with an ICD is calculated using radionuclide angiography utilizing planar multigated acquisition (MUGA) and first pass radionuclide angiography (FPRNA), respectively. Given the availability of MRI protocols that can accommodate patients with ICDs, we have correlated the findings of ventricular functional analysis using radionuclide angiography to cardiac MRI, the reference standard for ventricle function calculation, to directly correlate calculated ejection fractions between these modalities, and to also assess agreement between available echocardiographic and hemodynamic parameters of right ventricular function. A retrospective review from January 2012 through May 2014 was performed to identify advanced heart failure patients who underwent both cardiac MRI and radionuclide angiography for ventricular functional analysis. Nine heart failure patients (8 men, 1 woman; mean age of 57.0 years) were identified. The average time between the cardiac MRI and radionuclide angiography exams was 38.9 days (range: 1 - 119 days). All patients undergoing cardiac MRI were scanned using an institutionally approved protocol for ICD with no device-related complications identified. A retrospective chart review of each patient for cardiomyopathy diagnosis, clinical follow-up, and echocardiogram and right heart catheterization performed during evaluation was also performed. The 9 patients demonstrated a mean left ventricular ejection fraction (LVEF) using cardiac MRI of 20.7% (12 - 40%). Mean LVEF using MUGA was 22.6% (12 - 49%). The mean right ventricular ejection fraction (RVEF) utilizing cardiac MRI was 28.3% (16 - 43%), and the mean RVEF calculated by FPRNA was 32.6% (9 - 56%). The mean discrepancy for LVEF between cardiac MRI and MUGA was 4.1% (0 - 9%), and correlation of calculated LVEF using cardiac MRI and MUGA demonstrated an R of 0.9. The mean discrepancy for RVEF between cardiac MRI and FPRNA was 12.0% (range: 2 - 24%) with a moderate correlation (R = 0.5). The increased discrepancies for RV analysis were statistically significant using an unpaired t-test (t = 3.19, p = 0.0061). Echocardiogram parameters of RV function, including TAPSE and FAC, were for available for all 9 patients and agreement with cardiac MRI demonstrated a kappa statistic for TAPSE of 0.39 (95% CI of 0.06 - 0.72) and for FAC of 0.64 (95% of 0.21 - 1.00). Heart failure patients are increasingly requiring left ventricular assist device placement; however, definitive evaluation of biventricular function is required due to the increased mortality rate associated with right heart failure after assist device placement. Our results suggest that FPRNA only has a moderate correlation with reference standard RVEFs calculated using cardiac MRI, which was similar to calculated agreements between cardiac MRI and echocardiographic parameters of right ventricular function. Given the need for identification of patients at risk for right heart failure, further studies are warranted to determine a more accurate estimate of RVEF for heart failure patients during pre-operative ventricular assist device planning.

Electrostatic MEMS devices with high reliability

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

Goldsmith, Charles L; Auciello, Orlando H; Sumant, Anirudha V

The present invention provides for an electrostatic microelectromechanical (MEMS) device comprising a dielectric layer separating a first conductor and a second conductor. The first conductor is moveable towards the second conductor, when a voltage is applied to the MEMS device. The dielectric layer recovers from dielectric charging failure almost immediately upon removal of the voltage from the MEMS device.

Observations of Single Event Failure in Power MOSFETS

NASA Technical Reports Server (NTRS)

Nichols, D.; McCarty, K.; Coss, J.

1994-01-01

The first compendium of single event test data for power MOSFETs provides failure thresholds from burnout or gate rupture for over 100 devices of eight manufacturers. Ordering the data has also provided some useful insights.

Background and design of the profiling biobehavioral responses to mechanical support in advanced heart failure study.

PubMed

Lee, Christopher S; Mudd, James O; Gelow, Jill M; Nguyen, Thuan; Hiatt, Shirin O; Green, Jennifer K; Denfeld, Quin E; Bidwell, Julie T; Grady, Kathleen L

2014-01-01

Unexplained heterogeneity in response to ventricular assist device (VAD) implantation for the management of advanced heart failure impedes our ability to predict favorable outcomes, provide adequate patient and family education, and personalize monitoring and symptom management strategies. The purpose of this article was to describe the background and the design of a study entitled "Profiling Biobehavioral Responses to Mechanical Support in Advanced Heart Failure" (PREMISE). PREMISE is a prospective cohort study designed to (1) identify common and distinct trajectories of change in physical and psychological symptom burden; (2) characterize common trajectories of change in serum biomarkers of myocardial stress, systemic inflammation, and endothelial dysfunction; and (3) quantify associations between symptoms and biomarkers of pathogenesis in adults undergoing VAD implantation. Latent growth mixture modeling, including parallel process and cross-classification modeling, will be used to address the study aims and will entail identifying trajectories, quantifying associations between trajectories and both clinical and quality-of-life outcomes, and identifying predictors of favorable symptom and biomarker responses to VAD implantation. Research findings from the PREMISE study will be used to enhance shared patient and provider decision making and to shape a much-needed new breed of interventions and clinical management strategies that are tailored to differential symptom and pathogenic responses to VAD implantation.

Carbon Fiber Strand Tensile Failure Dynamic Event Characterization

NASA Technical Reports Server (NTRS)

Johnson, Kenneth L.; Reeder, James

2016-01-01

There are few if any clear, visual, and detailed images of carbon fiber strand failures under tension useful for determining mechanisms, sequences of events, different types of failure modes, etc. available to researchers. This makes discussion of physics of failure difficult. It was also desired to find out whether the test article-to-test rig interface (grip) played a part in some failures. These failures have nothing to do with stress rupture failure, thus representing a source of waste for the larger 13-00912 investigation into that specific failure type. Being able to identify or mitigate any competing failure modes would improve the value of the 13-00912 test data. The beginnings of the solution to these problems lay in obtaining images of strand failures useful for understanding physics of failure and the events leading up to failure. Necessary steps include identifying imaging techniques that result in useful data, using those techniques to home in on where in a strand and when in the sequence of events one should obtain imaging data.

Heart failure.

PubMed

Metra, Marco; Teerlink, John R

2017-10-28

Heart failure is common in adults, accounting for substantial morbidity and mortality worldwide. Its prevalence is increasing because of ageing of the population and improved treatment of acute cardiovascular events, despite the efficacy of many therapies for patients with heart failure with reduced ejection fraction, such as angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), β blockers, and mineralocorticoid receptor antagonists, and advanced device therapies. Combined angiotensin receptor blocker neprilysin inhibitors (ARNIs) have been associated with improvements in hospital admissions and mortality from heart failure compared with enalapril, and guidelines now recommend substitution of ACE inhibitors or ARBs with ARNIs in appropriate patients. Improved safety of left ventricular assist devices means that these are becoming more commonly used in patients with severe symptoms. Antidiabetic therapies might further improve outcomes in patients with heart failure. New drugs with novel mechanisms of action, such as cardiac myosin activators, are under investigation for patients with heart failure with reduced left ventricular ejection fraction. Heart failure with preserved ejection fraction is a heterogeneous disorder that remains incompletely understood and will continue to increase in prevalence with the ageing population. Although some data suggest that spironolactone might improve outcomes in these patients, no therapy has conclusively shown a significant effect. Hopefully, future studies will address these unmet needs for patients with heart failure. Admissions for acute heart failure continue to increase but, to date, no new therapies have improved clinical outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

16 CFR 1750.5 - Detailed requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... effects from spillage, cleaning, defrosting, and condensation. Devices shall be designed so that spillage... normal condensation will not so adversely affect the operation of the device as to result in its failure...

16 CFR 1750.5 - Detailed requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... effects from spillage, cleaning, defrosting, and condensation. Devices shall be designed so that spillage... normal condensation will not so adversely affect the operation of the device as to result in its failure...

16 CFR 1750.5 - Detailed requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... effects from spillage, cleaning, defrosting, and condensation. Devices shall be designed so that spillage... normal condensation will not so adversely affect the operation of the device as to result in its failure...

Analysis of field usage failure rate data for plastic encapsulated solid state devices

NASA Technical Reports Server (NTRS)

1981-01-01

Survey and questionnaire techniques were used to gather data from users and manufacturers on the failure rates in the field of plastic encapsulated semiconductors. It was found that such solid state devices are being successfully used by commercial companies which impose certain screening and qualification procedures. The reliability of these semiconductors is now adequate to support their consideration in NASA systems, particularly in low cost systems. The cost of performing necessary screening for NASA applications was assessed.

A Novel Multiscale Physics Based Progressive Failure Methodology for Laminated Composite Structures

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Waas, Anthony M.; Bednarcyk, Brett A.; Collier, Craig S.; Yarrington, Phillip W.

2008-01-01

A variable fidelity, multiscale, physics based finite element procedure for predicting progressive damage and failure of laminated continuous fiber reinforced composites is introduced. At every integration point in a finite element model, progressive damage is accounted for at the lamina-level using thermodynamically based Schapery Theory. Separate failure criteria are applied at either the global-scale or the microscale in two different FEM models. A micromechanics model, the Generalized Method of Cells, is used to evaluate failure criteria at the micro-level. The stress-strain behavior and observed failure mechanisms are compared with experimental results for both models.

The ABCs of managing systolic heart failure: Past, present, and future.

PubMed

Okwuosa, Ike Stanley; Princewill, Oluseyi; Nwabueze, Chiemeke; Mathews, Lena; Hsu, Steven; Gilotra, Nisha A; Lewsey, Sabra; Blumenthal, Roger S; Russell, Stuart D

2016-10-01

Heart failure management is complex and constantly evolving. The American College of Cardiology and the American Heart Association (ACC/AHA) last issued evidence-based guidelines in 2013, and since then, new drugs and devices have been developed. This review presents an evidence-based approach to current heart failure management. Copyright © 2016 Cleveland Clinic.

Support with intra-aortic balloon pump vs. Impella2.5® and blood flow to the heart, brain and kidneys - an experimental porcine model of ischaemic heart failure.

PubMed

Møller-Helgestad, Ole K; Poulsen, Christian B; Christiansen, Evald H; Lassen, Jens F; Ravn, Hanne B

2015-01-15

Cardiogenic shock as a complication to an acute myocardial infarction has an unacceptably high death rate that has not changed for the last 15years. Mortality is partly related to organ hypoperfusion and mechanical assist devices are used for the most severe cases but we do not know which assist device is the best option. Therefore, we have investigated how an IABP and an Impella®-pump influenced blood flow to the brain, heart and kidneys, in a closed-chest porcine model of severe left ventricular failure. 13 pigs were anesthetised and left ventricular failure was induced by occluding the proximal LAD for 45min followed by 30min of reperfusion. Blood flow was measured in the carotid artery, the LAD, and the renal artery. The Impella® and IABP were inserted via the femoral arteries, and the two devices were tested individually and combined after induction of heart failure. Carotid- (p=0.01) and renal blood flow (p=0.045) were higher on Impella®-support, compared to no support. None of the devices altered the blood flow in the LAD. Cardiac power output (p<0.005) and left ventricular work (p<0.00) were also higher on Impella®-support compared to no support. Haemodynamics and blood flow to the brain and kidneys were significantly better on Impella®-support, suggesting that the Impella® is superior to the IABP in a state of ischaemia induced left ventricular failure. These data, however, needs to be confirmed in a proper clinical trial with patients in cardiogenic shock. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effects of the August 2003 blackout on the New York City healthcare delivery system: a lesson for disaster preparedness.

PubMed

Prezant, David J; Clair, John; Belyaev, Stanislav; Alleyne, Dawn; Banauch, Gisela I; Davitt, Michelle; Vandervoorts, Kathy; Kelly, Kerry J; Currie, Brian; Kalkut, Gary

2005-01-01

On August 14, 2003, the United States and Canada suffered the largest power failure in history. We report the effects of this blackout on New York City's healthcare system by examining the following: 1) citywide 911 emergency medical service (EMS) calls and ambulance responses; and 2) emergency department (ED) visits and hospital admissions to one of New York City's largest hospitals. Citywide EMS calls and ambulance responses were categorized by 911 call type. Montefiore Medical Center (MMC) ED visits and hospital admissions were categorized by diagnosis and physician-reviewed for relationship to the blackout. Comparisons were made to the week pre- and postblackout. Citywide EMS calls numbered 5,299 on August 14, 2003, and 5,021 on August 15, 2003, a 58% increase (p < .001). During the blackout, there were increases in "respiratory" (189%; p < .001), "cardiac" (68%; p = .016), and "other" (40%; p < .001) EMS call categories, but when expressed as a percent of daily totals, "cardiac" was no longer significant. The MMC-ED reflected this surge with only "respiratory" visits significantly increased (expressed as percent of daily total visits; p < .001). Respiratory device failure (mechanical ventilators, positive pressure breathing assist devices, nebulizers, and oxygen compressors) was responsible for the greatest burden (65 MMC-ED visits, with 37 admissions) as compared with 0 pre- and postblackout. The blackout dramatically increased EMS and hospital activity, with unexpected increases resulting from respiratory device failures in community-based patients. Our findings suggest that current capacity to respond to public health emergencies could be easily overwhelmed by widespread/prolonged power failure(s). Disaster preparedness planning would be greatly enhanced if fully operational, backup power systems were mandated, not only for acute care facilities, but also for community-based patients dependent on electrically powered lifesaving devices.

A novel method for percutaneous insertion of a right ventricular assist device.

PubMed

Avgerinos, Dimitrios V; DeBois, William; Mongero, Linda; Krieger, Karl; Salemi, Arash

2013-06-01

Right heart failure is a rare but often fatal complication both in the pre- and postoperative setting. Right heart support with a ventricular assist device inserted in the operating room through median sternotomy can be a time-consuming procedure that requires a reoperation for removal. In cases of urgent need of right heart support, a percutaneous technique option may be of benefit. We present our initial experience with a percutaneously inserted right ventricular assist device (RVAD) in an elderly patient with severe right heart failure. An 81-year-old female patient underwent combined aortic and mitral valve replacement at our institution. During the first postoperative evening, the patient sustained sudden cardiovascular collapse and a bedside transesophageal echocardiogram revealed severe right heart failure. A coronary angiogram showed thrombosis of the right coronary artery, which was cleared with a suction device. As a result of the patient's critical condition, it was decided that an RVAD was needed as a bridge to recovery. The patient's condition improved significantly almost immediately. Her right heart function recovered over the next few days and the RVAD was removed at the bedside. She made a complete recovery and was discharged home. This patient is a prime example that a totally RVAD can be inserted in urgent situations easily and safely under fluoroscopic and echocardiographic guidance. More clinical experience with percutaneous RVADs is required to establish this technique as an alternative equivalent to the traditional open method. Right heart failure complicates many heart diseases both in the pre- and the postoperative setting. In cases of urgent need of right heart support, a percutaneous technique of a RVAD is needed for a successful outcome. We present our initial experience with a percutaneously inserted RVAD in an elderly patient with severe postoperative right heart failure.

Failure mechanisms and closed reduction of a constrained tripolar acetabular liner.

PubMed

Robertson, William J; Mattern, Christopher J; Hur, John; Su, Edwin P; Pellicci, Paul M

2009-02-01

Unlike traditional bipolar constrained liners, the Osteonics Omnifit constrained acetabular insert is a tripolar device, consisting of an inner bipolar bearing articulating within an outer, true liner. Every reported failure of the Omnifit tripolar implant has been by failure at the shell-bone interface (Type I failure), failure at the shell-liner interface (Type II failure), or failure of the locking mechanism resulting in dislocation of the bipolar-liner interface (Type III failure). In this report we present two cases of failure of the Omnifit tripolar at the bipolar-femoral head interface. To our knowledge, these are the first reported cases of failure at the bipolar-femoral head interface (Type IV failure). In addition, we described the first successful closed reduction of a Type IV failure.

16 CFR § 1750.5 - Detailed requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... effects from spillage, cleaning, defrosting, and condensation. Devices shall be designed so that spillage... normal condensation will not so adversely affect the operation of the device as to result in its failure...

New pharmacological and technological management strategies in heart failure

PubMed Central

Chaudhry, Sunit-Preet; Stewart, Garrick C

2017-01-01

Heart failure is a complex clinical syndrome resulting from impairment of ventricular filling or ejection of blood associated with symptoms of dyspnea, fatigue, as well as peripheral and/or pulmonary edema. This syndrome is progressive and characterized by worsening quality of life despite escalating levels of care, affecting 5.7 million Americans with an annual cost of over ≥30 billion US dollars. Treatment for this syndrome has evolved over three distinct eras: the nonpharmacological era, the pharmacological era, and the device era, with the focus shifting from symptomatic relief to decreasing morbidity and mortality. Over the past 10 years, the field has undergone a renaissance, with the development of new pharmacologic, hemodynamic monitoring, and device therapies proven to improve outcomes in patients with heart failure. This article will review several recent innovations in the management of patients with heart failure. PMID:28356751

Nonlinear structural crack growth monitoring

DOEpatents

Welch, Donald E.; Hively, Lee M.; Holdaway, Ray F.

2002-01-01

A method and apparatus are provided for the detection, through nonlinear manipulation of data, of an indicator of imminent failure due to crack growth in structural elements. The method is a process of determining energy consumption due to crack growth and correlating the energy consumption with physical phenomena indicative of a failure event. The apparatus includes sensors for sensing physical data factors, processors or the like for computing a relationship between the physical data factors and phenomena indicative of the failure event, and apparatus for providing notification of the characteristics and extent of such phenomena.

Influence of material quality and process-induced defects on semiconductor device performance and yield

NASA Technical Reports Server (NTRS)

Porter, W. A.; Mckee, W. R.

1974-01-01

An overview of major causes of device yield degradation is presented. The relationships of device types to critical processes and typical defects are discussed, and the influence of the defect on device yield and performance is demonstrated. Various defect characterization techniques are described and applied. A correlation of device failure, defect type, and cause of defect is presented in tabular form with accompanying illustrations.

Total Ionizing Dose Effects in Bipolar and BiCMOS Devices

NASA Technical Reports Server (NTRS)

Chavez, Rosa M.; Rax, Bernard G.; Scheick, Leif Z.; Johnston, Allan H.

2005-01-01

This paper describes total ionizing dose (TID) test results performed at JPL. Bipolar and BiCMOS device samples were tested exhibiting significant degradation and failures at different irradiation levels. Linear technology which is susceptible to low-dose dependency (ELDRS) exhibited greater damage for devices tested under zero bias condition.

Monitoring the health of power transformers

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

Kirtley, J.L. Jr.; Hagman, W.H.; Lesieutre, B.C.

This article reviews MIT`s model-based system which offers adaptive, intelligent surveillance of transformers, and summons attention to anomalous operation through paging devices. Failures of large power transformers are problematic for four reasons. Generally, large transformers are situated so that failures present operational problems to the system. In addition, large power transformers are encased in tanks of flammable and environmentally hazardous fluid. Failures are often accompanied by fire and/or spillage of this fluid. This presents hazards to people, other equipment and property, and the local environment. Finally, large power transformers are costly devices. There is a clear incentive for utilities tomore » keep track of the health of their power transformers. Massachusetts Institute of Technology (MIT) has developed an adaptive, intelligent, monitoring system for large power transformers. Four large transformers on the Boston Edison system are under continuous surveillance by this system, which can summon attention to anomalous operation through paging devices. The monitoring system offers two advantages over more traditional (not adaptive) methods of tracking transformer operation.« less

All-inkjet-printed thin-film transistors: manufacturing process reliability by root cause analysis.

PubMed

Sowade, Enrico; Ramon, Eloi; Mitra, Kalyan Yoti; Martínez-Domingo, Carme; Pedró, Marta; Pallarès, Jofre; Loffredo, Fausta; Villani, Fulvia; Gomes, Henrique L; Terés, Lluís; Baumann, Reinhard R

2016-09-21

We report on the detailed electrical investigation of all-inkjet-printed thin-film transistor (TFT) arrays focusing on TFT failures and their origins. The TFT arrays were manufactured on flexible polymer substrates in ambient condition without the need for cleanroom environment or inert atmosphere and at a maximum temperature of 150 °C. Alternative manufacturing processes for electronic devices such as inkjet printing suffer from lower accuracy compared to traditional microelectronic manufacturing methods. Furthermore, usually printing methods do not allow the manufacturing of electronic devices with high yield (high number of functional devices). In general, the manufacturing yield is much lower compared to the established conventional manufacturing methods based on lithography. Thus, the focus of this contribution is set on a comprehensive analysis of defective TFTs printed by inkjet technology. Based on root cause analysis, we present the defects by developing failure categories and discuss the reasons for the defects. This procedure identifies failure origins and allows the optimization of the manufacturing resulting finally to a yield improvement.

Pulsed laser ablation of IC packages for device failure analyses

NASA Astrophysics Data System (ADS)

Hong, Ming Hui; Mai, ZhiHong; Chen, G. X.; Thiam, Thomas; Song, Wen D.; Lu, Yongfeng; Soh, Chye E.; Chong, Tow Chong

2002-06-01

Pulsed laser ablation of mold compounds for IC packaging in air and with steam assistance is investigated. It is applied to decap IC packages and expose computer CPU dies for the device failure analyses. Compared with chemical decapping, the laser ablation has advantages of being fast speed, non- contact and dry processing. Laser ablation with the steam assistance results in higher ablation rate and wider ablated crater with much smoother surface morphology. It implies that the steam assisted laser ablation can achieve a faster and better quality laser processing. Audible acoustic wave and plasma optical signal diagnostics are also carried out to have a better understanding of the mechanisms behind. Light wavelength and laser fluence applied in the decapping are two important parameters. The 532 nm Nd:YAG laser decapping at a low laser fluence can achieve a large decapping area with a fine ablation profile. IC packages decapped by the laser ablation show good quality for the device failure analyses.

Voltage stress effects on microcircuit accelerated life test failure rates

NASA Technical Reports Server (NTRS)

Johnson, G. M.

1976-01-01

The applicability of Arrhenius and Eyring reaction rate models for describing microcircuit aging characteristics as a function of junction temperature and applied voltage was evaluated. The results of a matrix of accelerated life tests with a single metal oxide semiconductor microcircuit operated at six different combinations of temperature and voltage were used to evaluate the models. A total of 450 devices from two different lots were tested at ambient temperatures between 200 C and 250 C and applied voltages between 5 Vdc and 15 Vdc. A statistical analysis of the surface related failure data resulted in bimodal failure distributions comprising two lognormal distributions; a 'freak' distribution observed early in time, and a 'main' distribution observed later in time. The Arrhenius model was shown to provide a good description of device aging as a function of temperature at a fixed voltage. The Eyring model also appeared to provide a reasonable description of main distribution device aging as a function of temperature and voltage. Circuit diagrams are shown.

Heart failure - surgeries and devices

MedlinePlus

... right ventricular assist devices (RVAD) or a total artificial hearts. They are considered for use if you have ... be on a heart-lung bypass machine. Total artificial hearts are being developed, but are not yet in ...

Outcomes of Minimally Invasive Temporary Right Ventricular Assist Device Support for Acute Right Ventricular Failure During Minimally Invasive Left Ventricular Assist Device Implantation.

PubMed

Schaefer, Andreas; Reichart, Daniel; Bernhardt, Alexander M; Kubik, Mathias; Barten, Markus J; Wagner, Florian M; Reichenspurner, Hermann; Philipp, Sebastian A; Deuse, Tobias

Right ventricular failure (RVF) may still occur despite the benefits of minimally invasive left ventricular assist device (MI-LVAD) implantation. Our center strategy aims to avoid aggressive postoperative inotrope use by using mechanical support to facilitate right ventricle recovery and adaptation. We herein report first outcomes of patients with minimally invasive temporary right ventricular assist device (MI-t-RVAD) support for RVF during MI-LVAD implantation. Right ventricular failure was defined as requiring more than moderate inotopic support after weaning from cardiopulmonary bypass according to Interagency Registry for Mechanically Assisted Circulatory Support adverse event definitions. All patients requiring MI-t-RVAD support for RVF during MI-LVAD implantation between January, 2012 and April, 2016 were retrospectively reviewed. Clinical endpoints were death or unsuccessful RVAD weaning. Overall 10 patients (90% male, mean age 49.6 ± 14.8 years) underwent MI-t-RVAD implantation. Duration of MI-t-RVAD support was 16.2 ± 11.6 days. Right ventricular assist device weaning and subsequent uneventful awake device explantation was successful in all cases. The 30 day survival was 80%. Our results confirm safety and feasibility of MI-t-RVAD support for acute RVF in the setting of MI-LVAD implantation. The potential benefits of this strategy are more stable hemodynamics in the first postoperative days that usually are crucial for LVAD patients and reduced inotrope requirement.

49 CFR 232.403 - Design standards for one-way end-of-train devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Design standards for one-way end-of-train devices... Design standards for one-way end-of-train devices. (a) General. A one-way end-of-train device shall be... the rear unit from the brake pipe; (3) Designed so that an internal failure will not cause an...

49 CFR 232.403 - Design standards for one-way end-of-train devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Design standards for one-way end-of-train devices... Design standards for one-way end-of-train devices. (a) General. A one-way end-of-train device shall be... the rear unit from the brake pipe; (3) Designed so that an internal failure will not cause an...

49 CFR 232.403 - Design standards for one-way end-of-train devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Design standards for one-way end-of-train devices... Design standards for one-way end-of-train devices. (a) General. A one-way end-of-train device shall be... the rear unit from the brake pipe; (3) Designed so that an internal failure will not cause an...

A study of charged particles/radiation damage to VLSI device materials

NASA Technical Reports Server (NTRS)

Okyere, John G.

1987-01-01

Future spacecraft systems such as the manned space station will be subjected to low-dose long term radiation particles. Most electronic systems are affected by such particles. There is therefore a great need to understand device physics and failure mechanisms affected by radiation and to design circuits that would be less susceptible to radiation. Using 2 MeV electron radiation and bias temperature aging, it was found that MOS capacitors that were prepositively biased have lower flatband voltage shift and lesser increase in density of surface state charge than those that were not prepositively biased. In addition, it was shown that there is continued recovery of flatband voltage and density of state charge in irradiated capacitors during both room temperature anneal and 137 degree anneal. When nMOS transistors were subjected to 1 MeV proton radiation, charge pumping and current versus voltage measurements indicated that transconductance degradation, threshold voltage shifts and changes in interface states density may be the primary cause of nMOS transistor failure after radiation. Simulation studies using SPICE were performed on CMOS SRAM cells of various transistor sizes. It is shown that transistor sizing affects the noise margins of CMOS SRAM cells, and that as the beta ratio of the transistors of the CMOS SRAM cell decreases, the effective noise margin of the SRAM cell increases. Some suggestions were made in connection with the design of CMOS SRAMS that are hardened against single event upsets.

Stable room-temperature thallium bromide semiconductor radiation detectors

NASA Astrophysics Data System (ADS)

Datta, A.; Fiala, J.; Becla, P.; Motakef, Shariar

2017-10-01

Thallium bromide (TlBr) is a highly efficient ionic semiconductor with excellent radiation detection properties. However, at room temperature, TlBr devices polarize under an applied electric field. This phenomenon not only degrades the charge collection efficiency of the detectors but also promotes chemical reaction of the metal electrodes with bromine, resulting in an unstable electric field and premature failure of the device. This drawback has been crippling the TlBr semiconductor radiation detector technology over the past few decades. In this exhaustive study, this polarization phenomenon has been counteracted using innovative bias polarity switching schemes. Here the highly mobile Br- species, with an estimated electro-diffusion velocity of 10-8 cm/s, face opposing electro-migration forces during every polarity switch. This minimizes the device polarization and availability of Br- ions near the metal electrode. Our results indicate that it is possible to achieve longer device lifetimes spanning more than 17 000 h (five years of 8 × 7 operation) for planar and pixelated radiation detectors using this technique. On the other hand, at constant bias, 2500 h is the longest reported lifetime with most devices less than 1000 h. After testing several biasing switching schemes, it is concluded that the critical bias switching frequency at an applied bias of 1000 V/cm is about 17 μHz. Using this groundbreaking result, it will now be possible to deploy this highly efficient room temperature semiconductor material for field applications in homeland security, medical imaging, and physics research.

Mechanisms for fatigue and wear of polysilicon structural thinfilms

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

Alsem, Daniel Henricus

2006-01-01

Fatigue and wear in micron-scale polysilicon structural films can severely impact the reliability of microelectromechanical systems (MEMS). Despite studies on fatigue and wear behavior of these films, there is still an on-going debate regarding the precise physical mechanisms for these two important failure modes. Although macro-scale silicon does not fatigue, this phenomenon is observed in micron-scale silicon. It is shown that for polysilicon devices fabricated in the MUMPs foundry and SUMMiT process stress-lifetime data exhibits similar trends in ambient air, shorter lifetimes in higher relative humidity environments and no fatigue failure at all in high vacuum. Transmission electron microscopy ofmore » the surface oxides of the samples show an approximate four-fold thickening of the oxide at stress concentrations after fatigue failure, but no thickening after fracture in air or after fatigue cycling in vacuo. It is found that such oxide thickening and fatigue failure (in air) occurs in devices with initial oxide thicknesses of ~4-20 nm. Such results are interpreted and explained by a reaction layer fatigue mechanism; specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure. Polysilicon specimens from the SUMMiT process are used to study wear mechanisms in micron-scale silicon in ambient air. Worn parts are examined by analytical scanning and transmission electron microscopy, while temperature changes are monitored using infrared microscopy. These results are compared with the development of values of static coefficients of friction (COF) with number of wear cycles. Observations show amorphous debris particles (~50-100 nm) created by fracture through the silicon grains (~500 nm), which subsequently oxidize, agglomerate into clusters and create plowing tracks. A nano-crystalline layer (~20-200 nm) forms at worn regions. No dislocations or extreme temperature increases are found, ruling out plasticity and temperature-assisted mechanisms. The COF reaches a steady-state value of ~0.20±0.05 after a short time at an initial value of ~0.11±0.01. Plowing tracks are found before the steady-state value of the COF is reached, suggesting only a short adhesive wear regime. This suggests a predominantly abrasive wear mechanism, controlled by fracture, which commences by the first particles created by adhesive wear.« less

Mechanisms for fatigue and wear of polysilicon structural thin films

NASA Astrophysics Data System (ADS)

Alsem, Daniel Henricus

Fatigue and wear in micron-scale polysilicon structural films can severely impact the reliability of microelectromechanical systems (MEMS). Despite studies on fatigue and wear behavior of these films, there is still an on-going debate regarding the precise physical mechanisms for these two important failure modes. Although macro-scale silicon does not fatigue, this phenomenon is observed in micron-scale silicon. It is shown that for polysilicon devices fabricated in the MUMPs foundry and SUMMiT(TM) process stress-lifetime data exhibits similar trends in ambient air, shorter lifetimes in higher relative humidity environments and no fatigue failure at all in high vacuum. Transmission electron microscopy of the surface oxides of the samples show an approximate four-fold thickening of the oxide at stress concentrations after fatigue failure, but no thickening after fracture in air or after fatigue cycling in vacuo . It is found that such oxide thickening and fatigue failure (in air) occurs in devices with initial oxide thicknesses of ˜4-20 nm. Such results are interpreted and explained by a reaction-layer fatigue mechanism; specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure. Polysilicon specimens from the SUMMiT(TM) process are used to study wear mechanisms in micron-scale silicon in ambient air. Worn parts are examined by analytical scanning and transmission electron microscopy, while temperature changes are monitored using infrared microscopy. These results are compared with the development of values of static coefficients of friction (COF) with number of wear cycles. Observations show amorphous debris particles (˜50-100 nm) created by fracture through the silicon grains (˜500 nm), which subsequently oxidize, agglomerate into clusters and create plowing tracks. A nano-crystalline layer (˜20-200 nm) forms at worn regions. No dislocations or extreme temperature increases are found, ruling out plasticity and temperature-assisted mechanisms. The COF reaches a steady-state value of ˜0.20+/-0.05 after a short time at an initial value of ˜0.11+/-0.01. Plowing tracks are found before the steady-state value of the COF is reached, suggesting only a short adhesive wear regime. This suggests a predominantly abrasive wear mechanism, controlled by fracture, which commences by the first particles created by adhesive wear.

Hardware device to physical structure binding and authentication

DOEpatents

Hamlet, Jason R.; Stein, David J.; Bauer, Todd M.

2013-08-20

Detection and deterrence of device tampering and subversion may be achieved by including a cryptographic fingerprint unit within a hardware device for authenticating a binding of the hardware device and a physical structure. The cryptographic fingerprint unit includes an internal physically unclonable function ("PUF") circuit disposed in or on the hardware device, which generate an internal PUF value. Binding logic is coupled to receive the internal PUF value, as well as an external PUF value associated with the physical structure, and generates a binding PUF value, which represents the binding of the hardware device and the physical structure. The cryptographic fingerprint unit also includes a cryptographic unit that uses the binding PUF value to allow a challenger to authenticate the binding.

Telemetry Option in the Measurement of Physical Activity for Patients with Heart Failure

ERIC Educational Resources Information Center

Melczer, Csaba; Melczer, László; Oláh, András; Sélleyné-Gyúró, Mónika; Welker, Zsanett; Ács, Pongrác

2015-01-01

Measurement of physical activity among patients with heart failure typically requires a special approach due to the patients' physical status. Nowadays, a technology is already available that can measure the kinematic movements in 3-D by a pacemaker and implantable defibrillator giving an assessment on software. The telemetry data can be…

Quantitative modeling of total ionizing dose reliability effects in device silicon dioxide layers

NASA Astrophysics Data System (ADS)

Rowsey, Nicole L.

The electrical breakdown of oxides and oxide/semiconductor interfaces is one of the main reasons for device failure in integrated circuits, especially devices under high-stress conditions. One high-stress environment of interest is the space environment. All electronics are vulnerable to ionizing radiation; any high-energy particle that passes through an insulating layer will deposit unwanted charge there, causing shifts in device characteristics. Designing electronics for use in space can be a challenge, because much more energetic radiation exits in space than on Earth, as there is no atmosphere in space to collide with, and thereby reduce the energy of, energetic particles. Although oxide charging due to ionizing radiation creates well-known changes in device characteristics, or total ionizing dose effects, it is still poorly-understood exactly how these changes come about. There are many theories that draw upon a large body of both experimental work and, more recently, quantum-mechanical first principles calculations at the molecular level. This work uses FLOODS, a 3D object-oriented device simulator with multi-physics capability, to investigate these theories, by simulating oxide degradation in realistic device geometries, and comparing the subsequent degradation in device characteristics to experimental measurements. The charge trapping and defect-modulated transport models developed and implemented here have resulted in the first quantitative account of the enhanced low-dose-rate sensitivity effect, and are applicable in a comprehensive range of hydrogen environments. Measurements show that devices exposed to ionizing radiation at high dose rates exhibit less degradation that those exposed at low dose rates. Furthermore, the observed trend differs depending on the amount of hydrogen available before, during, and after irradiation. It is therefore important to understand and take into account the effects of dose rate and hydrogen when developing accelerated testing procedures for devices which have been exposed to various levels of hydrogen during processing and packaging, and which must be deployed in the low-dose-rate space environment. Thus, this work represents a substantial increase in the state-of-the-art, since a quantitative model has not previously been available. The success of the model is due in great part to the use of first-principles calculations of defect and hydrogen bond energies. Vanderbilt collaborators provided the results of these calculations as input to the FLOODS simulations. Using these physical insights, a sensitivity analysis in FLOODS yielded insights into key controlling parameters.

Angular velocity and acceleration meter

NASA Technical Reports Server (NTRS)

Melamed, L.

1972-01-01

Meter uses a liquid crystalline film which changes coloration due to shear-stresses produced by a rotating disk. Device is advantageous in that it is not subject to bearing failure or electrical burnouts as are conventional devices.

Silicon Carbide Power Device Performance Under Heavy-Ion Irradiation

NASA Technical Reports Server (NTRS)

Lauenstein, Jean-Marie; Casey, Megan; Topper, Alyson; Wilcox, Edward; Phan, Anthony; Ikpe, Stanley; LaBel, Ken

2015-01-01

Heavy-ion induced degradation and catastrophic failure data for SiC power MOSFETs and Schottky diodes are examined to provide insight into the challenge of single-event effect hardening of SiC power devices.

49 CFR 178.337-10 - Accident damage protection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... failure of the sacrificial device must leave the protected lading protection device and its attachment to the cargo tank wall intact and capable of retaining product. [Order 59-B, 30 FR 581, Jan. 16, 1965...

Adhesion and the Lamination/Failure of Stretchable Organic and Composite Organic/Inorganic Electronic Structures

NASA Astrophysics Data System (ADS)

Yu, Deying

Stretchable organic electronics have emerged as interesting technologies for several applications where stretchability is considered important. The easy and low-cost deposition procedures for the fabrication of stretchable organic solar cells and organic light emitting devices reduce the overall cost for the fabrication of these devices. However, the interfacial cracks and defects at the interfaces of the devices, during fabrication, are detrimental to the performance of stretchable organic electronic devices. Also, as the devices are deformed under service conditions, it is possible for cracks to grow. Furthermore, the multilayered structures of the devices can fail due to the delamination and buckling of the layered structures. There is, therefore, a need to study the failure mechanism in the layered structures that are relevant to stretchable organic electronic devices. Hence, in this study, a combined experimental, analytical and computational approach is used to study the effects of adhesion and deformation on the failure mechanisms in structures that are relevant to stretchable electronic devices. First, the failure mechanisms are studied in stretchable inorganic electronic structures. The wrinkles and buckles are formed by the unloading of pre-stretched PDMS/Au structure, after the evaporation of nano-scale Au layers. They are then characterized using atomic force microscopy and scanning electron microscopy. Analytical models are used to determine the critical stresses for wrinkling and buckling. The interfacial cracking and film buckling that can occur are also studied using finite element simulations. The implications of the results are then discussed for the potential applications of micro-wrinkles and micro-buckles in the stretchable electronic structures and biomedical devices. Subsequently, the adhesion between bi-material pairs that are relevant to organic light emitting devices, composite organic/inorganic light emitting devices, organic bulk heterojunction solar cells, and composite organic/inorganic solar cells on flexible substrates, is measured using force microscopy (AFM) techniques. The AFM measurements are incorporated into the Derjaguin-Muller-Toporov model to calculate the adhesion energies. The implications of the results are then discussed for the design of robust organic and composite organic/inorganic electronic devices. Finally, the lamination of organic solar cells and organic light emitting devices is studied using a combination of experimental, computational, and analytical approaches. First, the effects of applied lamination force (on contact between the laminated layers) are studied using experiments and models. The crack driving forces associated with the interfacial cracks that form at the interfaces between layers (at the bi-material interfaces) are estimated along with the critical interfacial crack driving forces associated with the separation of thin films, after layer transfer. The conditions for successful lamination are predicted using a combination of experiments and models. Guidelines are developed for the lamination of low-cost organic electronic structures.

21 CFR 890.5880 - Multi-function physical therapy table.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Multi-function physical therapy table. 890.5880 Section 890.5880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5880 Multi...

21 CFR 890.5880 - Multi-function physical therapy table.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Multi-function physical therapy table. 890.5880 Section 890.5880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5880 Multi...

21 CFR 890.5880 - Multi-function physical therapy table.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Multi-function physical therapy table. 890.5880 Section 890.5880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5880 Multi...

21 CFR 890.5880 - Multi-function physical therapy table.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Multi-function physical therapy table. 890.5880 Section 890.5880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5880 Multi...

21 CFR 890.5880 - Multi-function physical therapy table.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Multi-function physical therapy table. 890.5880 Section 890.5880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5880 Multi...

Remote monitoring of heart failure: benefits for therapeutic decision making.

PubMed

Martirosyan, Mihran; Caliskan, Kadir; Theuns, Dominic A M J; Szili-Torok, Tamas

2017-07-01

Chronic heart failure is a cardiovascular disorder with high prevalence and incidence worldwide. The course of heart failure is characterized by periods of stability and instability. Decompensation of heart failure is associated with frequent and prolonged hospitalizations and it worsens the prognosis for the disease and increases cardiovascular mortality among affected patients. It is therefore important to monitor these patients carefully to reveal changes in their condition. Remote monitoring has been designed to facilitate an early detection of adverse events and to minimize regular follow-up visits for heart failure patients. Several new devices have been developed and introduced to the daily practice of cardiology departments worldwide. Areas covered: Currently, special tools and techniques are available to perform remote monitoring. Concurrently there are a number of modern cardiac implantable electronic devices that incorporate a remote monitoring function. All the techniques that have a remote monitoring function are discussed in this paper in detail. All the major studies on this subject have been selected for review of the recent data on remote monitoring of HF patients and demonstrate the role of remote monitoring in the therapeutic decision making for heart failure patients. Expert commentary: Remote monitoring represents a novel intensified follow-up strategy of heart failure management. Overall, theoretically, remote monitoring may play a crucial role in the early detection of heart failure progression and may improve the outcome of patients.

75 FR 17143 - Draft Guidance for Industry and Food and Drug Administration Staff; Medical Devices; Neurological...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-05

... Physical Medicine Device Guidance Documents; Availability AGENCY: Food and Drug Administration, HHS. ACTION... controls guidance documents for 11 neurological and physical medicine devices. FDA has developed a draft... stimulator device achieves ``aesthetic effects through physical change to the structure of the body'' as well...

Electronic adherence monitoring device performance and patient acceptability: a randomized control trial.

PubMed

Chan, Amy Hai Yan; Stewart, Alistair William; Harrison, Jeff; Black, Peter Nigel; Mitchell, Edwin Arthur; Foster, Juliet Michelle

2017-05-01

To investigate the performance and patient acceptability of an inhaler electronic monitoring device in a real-world childhood asthma population. Children 6 to 15 years presenting with asthma to the hospital emergency department and prescribed inhaled corticosteroids were included. Participants were randomized to receive a device with reminder features enabled or disabled for use with their preventer. Device quality control tests were conducted. Questionnaires on device acceptability, utility and ergonomics were completed at six months. A total of 1306 quality control tests were conducted; 84% passed pre-issue and 87% return testing. The most common failure reason was actuation under-recording. Acceptability scores were high, with higher scores in the reminder than non-reminder group (median, 5 th -95 th percentile: 4.1, 3.1-5.0 versus 3.7, 2.3-4.8; p < 0.001). Most (>90%) rated the device easy to use. Feedback was positive across five themes: device acceptability, ringtone acceptability, suggestions for improvement, effect on medication use, and effect on asthma control. This study investigates electronic monitoring device performance and acceptability in children using quantitative and qualitative measures. Results indicate satisfactory reliability, although failure rates of 13-16% indicate the importance of quality control. Favorable acceptability ratings support the use of these devices in children.

US FDA perspective on regulatory issues affecting circulatory assist devices.

PubMed

Sapirstein, Wolf; Chen, Eric; Swain, Julie; Zuckerman, Bram

2006-11-01

There has been a rapid development in mechanical circulatory support systems in the decade since the US FDA first approved a mechanical device to provide the circulatory support lacking from a failing heart. Devices are presently approved for marketing by the FDA to replace a failing ventricle, the Ventricular Assist Device or the entire heart, Total Artificial Heart. Contemporaneous with, and permitted by, improvement in technology and design, devices have evolved from units located extracorporeally to paracorporeal systems and totally implanted devices. Clinical studies have demonstrated a parallel improvement in the homeostatic adequacy of the circulatory support provided. Thus, while the circulatory support was initially tolerated for short periods to permit recovery of cardiac function, this technology eventually provided effective circulatory support for increasing periods that permitted the FDA to approve devices for bridging patients in end-stage cardiac failure awaiting transplant and eventually a device for destination therapy where patients in end-stage heart failure are not cardiac transplant candidates. The approved devices have relied on displacement pumps that mimic the pulsatility of the physiological system. Accelerated development of more compact devices that rely on alternative pump mechanisms have challenged both the FDA and device manufacturers to assure that the regulatory requirements for safety and effectiveness are met for use of mechanical circulatory support systems in expanded target populations. An FDA regulatory perspective is reviewed of what can be a potentially critical healthcare issue.

Ergonomic evaluation of 3D plane positioning using a mouse and a haptic device.

PubMed

Paul, Laurent; Cartiaux, Olivier; Docquier, Pierre-Louis; Banse, Xavier

2009-12-01

Preoperative planning and intraoperative assistance are needed to improve accuracy in tumour surgery. To be accepted, these processes must be efficient. An experiment was conducted to compare a mouse and a haptic device, with and without force feedback, to perform plan positioning in a 3D space. Ergonomics and performance factors were investigated during the experiment. Positioning strategies were observed. The task completion time, number of 3D orientations and failure rate were analysed. A questionnaire on ergonomics was filled out by each participant. The haptic device showed a significantly lower failure rate and was quicker and more ergonomic than the mouse. The force feedback was not beneficial to the accomplishment of the task. The haptic device is intuitive, ergonomic and more efficient than the mouse for positioning a 3D plane into a 3D space. Useful observations regarding positioning strategies will improve the integration of haptic devices into medical applications. Copyright (c) 2009 John Wiley & Sons, Ltd.

A Model of BGA Thermal Fatigue Life Prediction Considering Load Sequence Effects

PubMed Central

Hu, Weiwei; Li, Yaqiu; Sun, Yufeng; Mosleh, Ali

2016-01-01

Accurate testing history data is necessary for all fatigue life prediction approaches, but such data is always deficient especially for the microelectronic devices. Additionally, the sequence of the individual load cycle plays an important role in physical fatigue damage. However, most of the existing models based on the linear damage accumulation rule ignore the sequence effects. This paper proposes a thermal fatigue life prediction model for ball grid array (BGA) packages to take into consideration the load sequence effects. For the purpose of improving the availability and accessibility of testing data, a new failure criterion is discussed and verified by simulation and experimentation. The consequences for the fatigue underlying sequence load conditions are shown. PMID:28773980

Comparison of home and away-from-home physical activity using accelerometers and cellular network-based tracking devices.

PubMed

Ramulu, Pradeep Y; Chan, Emilie S; Loyd, Tara L; Ferrucci, Luigi; Friedman, David S

2012-08-01

Measuring physical at home and away from home is essential for assessing health and well-being, and could help design interventions to increase physical activity. Here, we describe how physical activity at home and away from home can be quantified by combining information from cellular network-based tracking devices and accelerometers. Thirty-five working adults wore a cellular network-based tracking device and an accelerometer for 6 consecutive days and logged their travel away from home. Performance of the tracking device was determined using the travel log for reference. Tracking device and accelerometer data were merged to compare physical activity at home and away from home. The tracking device detected 98.6% of all away-from-home excursions, accurately measured time away from home and demonstrated few prolonged signal drop-out periods. Most physical activity took place away from home on weekdays, but not on weekends. Subjects were more physically active per unit of time while away from home, particularly on weekends. Cellular network-based tracking devices represent an alternative to global positioning systems for tracking location, and provide information easily integrated with accelerometers to determine where physical activity takes place. Promoting greater time spent away from home may increase physical activity.

Effects of ionizing radiation on charge-coupled imagers

NASA Technical Reports Server (NTRS)

Killiany, J. M.; Baker, W. D.; Saks, N. S.; Barbe, D. F.

1975-01-01

The effects of ionizing radiation on three different charge coupled imagers have been investigated. Device performance was evaluated as a function of total gamma ray dose. The principal failure mechanisms have been identified for each particular device structure. The clock and bias voltages required for high total dose operation of the devices are presented.

Sexual counseling and cardiovascular disease: practical approaches

PubMed Central

Steinke, Elaine E; Jaarsma, Tiny

2015-01-01

Patients with cardiovascular disease and their partners expect health care providers to provide sexual counseling to assist them in maintaining sexual quality of life. Evidence suggests however, that there is a gap in integrating evidence into practice and that relatively few cardiac patients receive sexual counseling. This can result in negative psychological, physical, and quality of life outcomes for couples who may needlessly decide sexual activity is too risky and cease all sexual activity. Two scientific statements now exist that provide ample guidance to health care providers in discussing this important topic. Using a team approach that includes physicians, nurses, physical therapists, rehabilitation staff, and others is important to ensure that sexual counseling occurs throughout recovery. In addition, several trials using interventional approaches for sexual counseling provide insight into successful approaches for sexual counseling in practice. This article provides practical strategies and evidence-based approaches for assessment and sexual counseling for all cardiac patients and their partners, and specific counseling for those with ischemic conditions, heart failure, and implanted devices. PMID:25219908

Sexual counseling and cardiovascular disease: practical approaches.

PubMed

Steinke, Elaine E; Jaarsma, Tiny

2015-01-01

Patients with cardiovascular disease and their partners expect health care providers to provide sexual counseling to assist them in maintaining sexual quality of life. Evidence suggests however, that there is a gap in integrating evidence into practice and that relatively few cardiac patients receive sexual counseling. This can result in negative psychological, physical, and quality of life outcomes for couples who may needlessly decide sexual activity is too risky and cease all sexual activity. Two scientific statements now exist that provide ample guidance to health care providers in discussing this important topic. Using a team approach that includes physicians, nurses, physical therapists, rehabilitation staff, and others is important to ensure that sexual counseling occurs throughout recovery. In addition, several trials using interventional approaches for sexual counseling provide insight into successful approaches for sexual counseling in practice. This article provides practical strategies and evidence-based approaches for assessment and sexual counseling for all cardiac patients and their partners, and specific counseling for those with ischemic conditions, heart failure, and implanted devices.

[Examination of safety improvement by failure record analysis that uses reliability engineering].

PubMed

Kato, Kyoichi; Sato, Hisaya; Abe, Yoshihisa; Ishimori, Yoshiyuki; Hirano, Hiroshi; Higashimura, Kyoji; Amauchi, Hiroshi; Yanakita, Takashi; Kikuchi, Kei; Nakazawa, Yasuo

2010-08-20

How the maintenance checks of the medical treatment system, including start of work check and the ending check, was effective for preventive maintenance and the safety improvement was verified. In this research, date on the failure of devices in multiple facilities was collected, and the data of the trouble repair record was analyzed by the technique of reliability engineering. An analysis of data on the system (8 general systems, 6 Angio systems, 11 CT systems, 8 MRI systems, 8 RI systems, and the radiation therapy system 9) used in eight hospitals was performed. The data collection period assumed nine months from April to December 2008. Seven items were analyzed. (1) Mean time between failures (MTBF) (2) Mean time to repair (MTTR) (3) Mean down time (MDT) (4) Number found by check in morning (5) Failure generation time according to modality. The classification of the breakdowns per device, the incidence, and the tendency could be understood by introducing reliability engineering. Analysis, evaluation, and feedback on the failure generation history are useful to keep downtime to a minimum and to ensure safety.

Role of long-term mechanical circulatory support in patients with advanced heart failure.

PubMed

Stokes, M B; Bergin, P; McGiffin, D

2016-05-01

Advanced heart failure represents a small proportion of patients with heart failure that possess high-risk features associated with high hospital readmission rates, significant functional impairment and mortality. Identification of those who have progressed to, or are near a state of advanced heart failure should prompt referral to a service that offers therapies in mechanical circulatory support (MCS) and cardiac transplantation. MCS has grown as a management strategy in the care of these patients, most commonly as a bridge to cardiac transplantation. The predominant utilisation of MCS is implantation of left ventricular assist devices (LVAD), which have evolved significantly in their technology and application over the past 15-20 years. The technology has evolved to such an extent that Destination Therapy is now being utilised as a strategy in management of advanced heart failure in appropriately selected patients. Complication rates have decreased with VAD implantation, but remain a significant consideration in the decision to implant a device, and in the follow up of these patients. © 2016 Royal Australasian College of Physicians.

Update for 2014 on clinical cardiology, geriatric cardiology, and heart failure and transplantation.

PubMed

Barón-Esquivias, Gonzalo; Manito, Nicolás; López Díaz, Javier; Martín Santana, Antonio; García Pinilla, José Manuel; Gómez Doblas, Juan José; Gómez Bueno, Manuel; Barrios Alonso, Vivencio; Lambert, José Luis

2015-04-01

In the present article, we review publications from the previous year in the following 3 areas: clinical cardiology, geriatric cardiology, and heart failure and transplantation. Among the new developments in clinical cardiology are several contributions from Spanish groups on tricuspid and aortic regurgitation, developments in atrial fibrillation, syncope, and the clinical characteristics of heart disease, as well as various studies on familial heart disease and chronic ischemic heart disease. In geriatric cardiology, the most relevant studies published in 2014 involve heart failure, degenerative aortic stenosis, and data on atrial fibrillation in the geriatric population. In heart failure and transplantation, the most noteworthy developments concern the importance of multidisciplinary units and patients with preserved systolic function. Other notable publications were those related to iron deficiency, new drugs, and new devices and biomarkers. Finally, we review studies on acute heart failure and transplantation, such as inotropic drugs and ventricular assist devices. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Reliability of hybrid microcircuit discrete components

NASA Technical Reports Server (NTRS)

Allen, R. V.

1972-01-01

Data accumulated during 4 years of research and evaluation of ceramic chip capacitors, ceramic carrier mounted active devices, beam-lead transistors, and chip resistors are presented. Life and temperature coefficient test data, and optical and scanning electron microscope photographs of device failures are presented and the failure modes are described. Particular interest is given to discrete component qualification, power burn-in, and procedures for testing and screening discrete components. Burn-in requirements and test data will be given in support of 100 percent burn-in policy on all NASA flight programs.

78 FR 38867 - Gastroenterology-Urology Devices; Reclassification of Implanted Blood Access Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... artificial kidney system for the treatment of patients with renal failure or toxemic conditions and provides... into the heart or blood vessel could damage tissues and result in injuries. Hemolysis. Turbulence or...

Left Ventricular Assist Devices: The Adolescence of a Disruptive Technology.

PubMed

Pinney, Sean P

2015-10-01

Clinical outcomes for patients with advanced heart failure receiving left ventricular assist devices are driven by appropriate patient selection, refined surgical technique, and coordinated medical care. Perhaps even more important is innovative pump design. The introduction and widespread adoption of continuous-flow ventricular assist devices has led to a paradigm shift within the field of mechanical circulatory support, making the promise of lifetime device therapy closer to reality. The disruption caused by this new technology, on the one hand, produced meaningful improvements in patient survival and quality of life, but also introduced new clinical challenges, such as bleeding, pump thrombosis, and acquired valvular heart disease. Further evolution within this field will require financial investment to sustain innovation leading to a fully implantable, durable, and cost-effective pump for a larger segment of patients with advanced heart failure. Copyright © 2015 Elsevier Inc. All rights reserved.

Myocardial recovery during mechanical circulatory support: long-term outcome and elective ventricular assist device implantation to promote recovery as a treatment goal.

PubMed

Dandel, Michael; Hetzer, Roland

2015-01-01

Even after incomplete myocardial recovery during mechanical circulatory support, long-term survival rates after ventricular assist device (VAD) explantation can be better than those expected after heart transplantation even for patients with chronic non-ischemic cardiomyopathy as the underlying cause for VAD implantation. The elective therapeutic use of ventricular assist devices for heart failure reversal in its early stage is a future goal. It may be possible to achieve it by developing tools to predict heart failure reversibility even before ventricular assist device implantation and increasing the number of weaning candidates by improvement of adjunctive therapies to optimize unloading-promoted recovery.  Special attention is focused on the long-term stability of cardiac remission after VAD removal, the clinical relevance unloading-promoted myocardial recovery and on the current knowledge about a potential prediction of myocardial recovery during long-term VAD support already before VAD implantation.

Successfully treated necrotizing fasciitis using extracorporeal life support combined with hemoadsorption device and continuous renal replacement therapy.

PubMed

Eid, Maroua; Fouquet, Olivier; Darreau, Cédric; Pierrot, Marc; Kouatchet, Achille; Mercat, Alain; Baufreton, Christophe

2018-03-01

Necrotizing fasciitis represents a life-threatening infectious condition that causes spreading necrotisis of superficial fascia and subcutaneous cellular tissues. We describe the case of a patient diagnosed with septic and toxic shocks leading to multiple organ failure successfully treated with a combination of extracorporeal life support, continuous renal replacement therapy, and a hemoadsorption device. A 41-year-old patient presented with necrotizing fasciitis and multi-organ failure. Initial extracorporeal life support therapy was implanted, compensating for systolic failure. Due to acute renal failure that persisted in time, continuous renal replacement therapy was added. Despite these treatments and as a last attempt to control the septic condition, a CytoSorb ® hemoadsorption device was installed in parallel to the extracorporeal life support circuit and two sessions were run. During the days following CytoSorb ® treatment, hemodynamic stabilization was observed, as well as normalization of lactic acidosis and blood parameters. This case describes the successful use of CytoSorb ® with continuous renal replacement therapy and extracorporeal life support in a combined way to overcome a critical phase of septic shock in a young adult patient. This combination of treatments turned out to be efficient for this patient in the context of necrotizing fasciitis.

Impact of applying the more stringent validation criteria of the revised European Society of Hypertension International Protocol 2010 on earlier validation studies.

PubMed

Stergiou, George S; Karpettas, Nikos; Atkins, Neil; O'Brien, Eoin

2011-04-01

Since 2002 when the European Society of Hypertension International Protocol (ESH-IP) was published it has become the preferred protocol for validating blood pressure monitors worldwide. In 2010, a revised version of the ESH-IP with more stringent criteria was published. This study assesses the impact of applying the revised ESH-IP criteria. A systematic literature review of ESH-IP studies reported between 2002 and 2010 was conducted. The impact of applying the ESH-IP 2010 criteria retrospectively on the data reported in these studies was investigated. The performance of the oscillometric devices in the last decade was also investigated on the basis of the ESH-IP criteria. Among 119 published studies, 112 with sufficient data were analyzed. According to ESH-IP 2002, the test device failed in 19 studies, whereas by applying the ESH-IP 2010 criteria in 28 additional studies increased the failure rate from 17 to 42%. Of these 28 studies, in 20 (71%) the test device failed at part 1 (accuracy per measurement) and in 22 (79%) at part 2 (accuracy per subject). Most of the failures involved the '5 mmHg or less' criterion. In the last decade there has been a consistent trend toward improved performance of oscillometric devices assessed on the basis of the ESH-IP criteria. This retrospective analysis shows that the stricter revised ESH-IP 2010 criteria will noticeably increase the failure rate of devices being validated. Oscillometric devices are becoming more accurate, and the revised ESH-IP by acknowledging this trend will allow more accurate devices to enter the market.

German disease management guidelines: surgical therapies for chronic heart failure.

PubMed

Sindermann, J R; Klotz, S; Rahbar, K; Hoffmeier, A; Drees, G

2010-02-01

The German Disease Management Guideline "Chronic Heart Failure" intends to guide physicians working in the field of diagnosis and treatment of heart failure. The guideline provides a tool on the background of evidence based medicine. The following short review wants to give insights into the role of some surgical treatment options to improve heart failure, such as revascularization, ventricular reconstruction and aneurysmectomy, mitral valve reconstruction, ventricular assist devices and heart transplantation. (c) Georg Thieme Verlag KG Stuttgart-New York.

Predicting Failure Under Laboratory Conditions: Learning the Physics of Slow Frictional Slip and Dynamic Failure

NASA Astrophysics Data System (ADS)

Rouet-Leduc, B.; Hulbert, C.; Riviere, J.; Lubbers, N.; Barros, K.; Marone, C.; Johnson, P. A.

2016-12-01

Forecasting failure is a primary goal in diverse domains that include earthquake physics, materials science, nondestructive evaluation of materials and other engineering applications. Due to the highly complex physics of material failure and limitations on gathering data in the failure nucleation zone, this goal has often appeared out of reach; however, recent advances in instrumentation sensitivity, instrument density and data analysis show promise toward forecasting failure times. Here, we show that we can predict frictional failure times of both slow and fast stick slip failure events in the laboratory. This advance is made possible by applying a machine learning approach known as Random Forests1(RF) to the continuous acoustic emission (AE) time series recorded by detectors located on the fault blocks. The RF is trained using a large number of statistical features derived from the AE time series signal. The model is then applied to data not previously analyzed. Remarkably, we find that the RF method predicts upcoming failure time far in advance of a stick slip event, based only on a short time window of data. Further, the algorithm accurately predicts the time of the beginning and end of the next slip event. The predicted time improves as failure is approached, as other data features add to prediction. Our results show robust predictions of slow and dynamic failure based on acoustic emissions from the fault zone throughout the laboratory seismic cycle. The predictions are based on previously unidentified tremor-like acoustic signals that occur during stress build up and the onset of macroscopic frictional weakening. We suggest that the tremor-like signals carry information about fault zone processes and allow precise predictions of failure at any time in the slow slip or stick slip cycle2. If the laboratory experiments represent Earth frictional conditions, it could well be that signals are being missed that contain highly useful predictive information. 1Breiman, L. Random forests. Machine Learning 45, 5-32 (2001). 2Rouet-Leduc, B. C. Hulbert, N. Lubbers, K. Barros and P. A. Johnson, Learning the physics of failure, in review (2016).

21 CFR 890.3665 - Congenital hip dislocation abduction splint.

Code of Federal Regulations, 2010 CFR

2010-04-01

... SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890... abduction splint is a device intended for medical purposes to stabilize the hips of a young child with...

Statistical study of the reliability of oxide-defined stripe cw lasers of (AlGa)As

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

Ettenberg, M.

1979-03-01

In this report, we describe a statistical study of the reliability of oxide-defined stripe-contact cw injection lasers of (AlGa)As. These devices have one facet coated with Al/sub 2/O/sub 3/ and one facet coated with an Al/sub 2/O/sub 3//Si dichroic reflector; the lasers are optimized for cw low-threshold currents at room temperature, with values typically about 50 mA. Lifetests were carried out at 70 /sup 0/C ambient, in the cw mode of operation with about 5 mW output. Previous lifetests showed that the degradation rate followed a 0.95-eV activation energy so the 70 /sup 0/C environment provides a degradation acceleration factormore » of 190 over that at room temperature. We have found that the device failures follow a log-normal distribution, characterized by a mean time before failure of 4200 h and a standard deviation of 1.3. This corresponds to a mean time to failure (MTTF) of 10/sup 6/ h at room temperature. Failure is defined here as the inability of the device to emit 1 mW of stimulated cw output at 70 /sup 0/C, and assumes that optical feedback will be employed to adjust the laser current during operation. If a constant-current drive is envisioned, the failures for a 3-dB drop in light output also follow a log-normal distribution with a similar slope (standard deviation=1.1) and a MTTF of 2000 h at 70 /sup 0/C (500 000 h at room temperature). The failures were found to be mainly due to bulk gradual degradation and not facet or contact failure. Careful study of lasers before and after lifetest showed a significant increase in contact thermal resistance. However, this increase accounts for only a small portion of the nearly 70% increase in room-temperature cw threshold after failure at 70 /sup 0/C. After failure at 70 /sup 0/C, we also noted a degradation in the near-field and associated far-field pattern of the laser.« less

Evaluation of 1.5-T Cell Flash Memory Total Ionizing Dose Response

NASA Astrophysics Data System (ADS)

Clark, Lawrence T.; Holbert, Keith E.; Adams, James W.; Navale, Harshad; Anderson, Blake C.

2015-12-01

Flash memory is an essential part of systems used in harsh environments, experienced by both terrestrial and aerospace TID applications. This paper presents studies of COTS flash memory TID hardness. While there is substantial literature on flash memory TID response, this work focuses for the first time on 1.5 transistor per cell flash memory. The experimental results show hardness varying from about 100 krad(Si) to over 250 krad(Si) depending on the usage model. We explore the circuit and device aspects of the results, based on the extensive reliability literature for this flash memory type. Failure modes indicate both device damage and circuit marginalities. Sector erase failure limits, but read only operation allows TID exceeding 200 krad(Si). The failures are analyzed by type.

Domestic and foreign trends in the prevalence of heart failure and the necessity of next-generation artificial hearts: a survey by the Working Group on Establishment of Assessment Guidelines for Next-Generation Artificial Heart Systems.

PubMed

Tatsumi, Eisuke; Nakatani, Takeshi; Imachi, Kou; Umezu, Mitsuo; Kyo, Shun-Ei; Sase, Kazuhiro; Takatani, Setsuo; Matsuda, Hikaru

2007-01-01

A series of guidelines for development and assessment of next-generation medical devices has been drafted under an interagency collaborative project by the Ministry of Health, Labor and Welfare and the Ministry of Economy, Trade and Industry. The working group for assessment guidelines of next-generation artificial hearts reviewed the trend in the prevalence of heart failure and examined the potential usefulness of such devices in Japan and in other countries as a fundamental part of the process of establishing appropriate guidelines. At present, more than 23 million people suffer from heart failure in developed countries, including Japan. Although Japan currently has the lowest mortality from heart failure among those countries, the number of patients is gradually increasing as our lifestyle becomes more Westernized; the associated medical expenses are rapidly growing. The number of heart transplantations, however, is limited due to the overwhelming shortage of donor hearts, not only in Japan but worldwide. Meanwhile, clinical studies and surveys have revealed that the major causes of death in patients undergoing long-term use of ventricular assist devices (VADs) were infection, thrombosis, and mechanical failure, all of which are typical of VADs. It is therefore of urgent and universal necessity to develop next-generation artificial hearts that have excellent durability to provide at least 2 years of event-free operation with a superior quality of life and that can be used for destination therapy to save patients with irreversible heart failure. It is also very important to ensure that an environment that facilitates the development, testing, and approval evaluation processes of next-generation artificial hearts be established as soon as possible.

Risk Factors for Treatment Failure With the Adjustable Transobturator Male System Incontinence Device: Who Will Succeed, Who Will Fail? Results of a Multicenter Study.

PubMed

Friedl, Alexander; Mühlstädt, Sandra; Rom, Maximilian; Kivaranovic, Danijel; Mohammed, Nasreldin; Fornara, Paolo; Brössner, Clemens

2016-04-01

To identify risk factors for treatment failure of men with the adjustable transobturator male system (ATOMS) for treating stress urinary incontinence (SUI). Sixty-two patients with SUI after prostate surgery were provided with an ATOMS. The self-defined criteria for treatment failure (implant removal [A], no improvement or ≥3 pads/24 hours [B], and no improvement or ≥150 mL urine loss/24 hours [C]) were compared to anamnestic, clinical, and time-specific parameters: age, Charlson comorbidity index (CCI), urine culture (UC), previous ineffective implants, body mass index, radiotherapy, renal function (serum creatinine), smoker status, urethral strictures, SUI severity, surgery time, time to and season at implantation, and port system application. After a median follow-up of 17.7 months, 9 ATOMS (15%) were removed due to infection (8) or dysfunction (1); 23% and 16% had treatment failure of criteria B and C. Dry rate/overall success rate was 61%/87%. Age alone was no risk factor but the CCI and a positive UC were univariate significant predictors of the criteria A, B, and C. Besides, previous devices and renal failure were significantly associated with implant removal (A) and SUI severity with criterion C. In multivariate analysis, previous devices (P = .0163), positive UC (P = .0190), and SUI severity (P = .0123) were the strongest predictors of A, B, and C, respectively. A poor CCI, preoperative positive UC, severe SUI, and previous implants lead to more treatment failure and removal. Age, body mass index, radiotherapy, urethral strictures, current smoking, time-specific parameters, seasonality, and port system application did not influence the outcome. Copyright © 2016 Elsevier Inc. All rights reserved.

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

Bolenbaugh, Jonathan M.; Naqi, Syed

A method to operate a clutch device in an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and at least one electric machine includes, in response to a failure condition detected within a flow control device configured to facilitate flow of hydraulic fluid for operating the clutch device, selectively preventing the flow of hydraulic fluid from entering the flow control device and feeding the clutch device. Synchronization of the clutch device is initiated when the clutch device is intended for activation, and only if the clutch device is synchronized, the flow of hydraulic fluid is selectively permitted to entermore » the flow control device to activate the clutch device.« less

21 CFR 890.5525 - Iontophoresis device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Iontophoresis device. 890.5525 Section 890.5525 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5525 Iontophoresis...

21 CFR 890.5525 - Iontophoresis device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Iontophoresis device. 890.5525 Section 890.5525 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5525 Iontophoresis...

21 CFR 890.5525 - Iontophoresis device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Iontophoresis device. 890.5525 Section 890.5525 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5525 Iontophoresis...

21 CFR 890.5525 - Iontophoresis device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Iontophoresis device. 890.5525 Section 890.5525 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5525 Iontophoresis...

21 CFR 890.5525 - Iontophoresis device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Iontophoresis device. 890.5525 Section 890.5525 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5525 Iontophoresis...

Nondestructive SEM for surface and subsurface wafer imaging

NASA Technical Reports Server (NTRS)

Propst, Roy H.; Bagnell, C. Robert; Cole, Edward I., Jr.; Davies, Brian G.; Dibianca, Frank A.; Johnson, Darryl G.; Oxford, William V.; Smith, Craig A.

1987-01-01

The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices.

Piezoelectrically Initiated Pyrotechnic Igniter

NASA Technical Reports Server (NTRS)

Quince, Asia; Dutton, Maureen; Hicks, Robert; Burnham, Karen

2013-01-01

This innovation consists of a pyrotechnic initiator and piezoelectric initiation system. The device will be capable of being initiated mechanically; resisting initiation by EMF, RF, and EMI (electromagnetic field, radio frequency, and electromagnetic interference, respectively); and initiating in water environments and space environments. Current devices of this nature are initiated by the mechanical action of a firing pin against a primer. Primers historically are prone to failure. These failures are commonly known as misfires or hang-fires. In many cases, the primer shows the dent where the firing pin struck the primer, but the primer failed to fire. In devices such as "T" handles, which are commonly used to initiate the blowout of canopies, loss of function of the device may result in loss of crew. In devices such as flares or smoke generators, failure can result in failure to spot a downed pilot. The piezoelectrically initiated ignition system consists of a pyrotechnic device that plugs into a mechanical system (activator), which on activation, generates a high-voltage spark. The activator, when released, will strike a stack of electrically linked piezo crystals, generating a high-voltage, low-amperage current that is then conducted to the pyro-initiator. Within the initiator, an electrode releases a spark that passes through a pyrotechnic first-fire mixture, causing it to combust. The combustion of the first-fire initiates a primary pyrotechnic or explosive powder. If used in a "T" handle, the primary would ramp the speed of burn up to the speed of sound, generating a shock wave that would cause a high explosive to go "high order." In a flare or smoke generator, the secondary would produce the heat necessary to ignite the pyrotechnic mixture. The piezo activator subsystem is redundant in that a second stack of crystals would be struck at the same time with the same activation force, doubling the probability of a first strike spark generation. If the first activation fails to ignite, the device is capable of multiple attempts. Another unique aspect is in the design of the pyrotechnic device. There is an electrode that aids the generation of a directed spark and the use of a conductive matrix to support the first-fire material so that the spark will penetrate to the second electrode.

Assessment of Safety and Effectiveness of the Extracorporeal Continuous-Flow Ventricular Assist Device (BR16010) Use as a Bridge-to-Decision Therapy for Severe Heart Failure or Refractory Cardiogenic Shock: Study Protocol for Single-Arm Non-randomized, Uncontrolled, and Investigator-Initiated Clinical Trial.

PubMed

Fukushima, Norihide; Tatsumi, Eisuke; Seguchi, Osamu; Takewa, Yoshiaki; Hamasaki, Toshimitsu; Onda, Kaori; Yamamoto, Haruko; Hayashi, Teruyuki; Fujita, Tomoyuki; Kobayashi, Junjiro

2018-06-08

The management of heart failure patients presenting in a moribund state remains challenging, despite significant advances in the field of ventricular assist systems. Bridge to decision involves using temporary devices to stabilize the hemodynamic state of such patients while further assessment is performed and a decision can be made regarding patient management. The purpose of this study (NCVC-BTD_01, National Cerebral and Cardiovascular Center-Bridge to Dicision_01) is to assess the safety and effectiveness of the newly developed extracorporeal continuous-flow ventricular assist system employing a disposable centrifugal pump with a hydrodynamically levitated bearing (BR16010) use as a bridge-to-decision therapy for patients with severe heart failure or refractory cardiogenic shock. NCVC-BTD_01 is a single-center, single-arm, open-label, exploratory, medical device, investigator-initiated clinical study. It is conducted at the National Cerebral and Cardiovascular Center in Japan. A total of nine patients will be enrolled in the study. The study was planned using Simon's minimax two-stage phase design. The primary endpoint is a composite of survival free of device-related serious adverse events and complications during device support. For left ventricular assistance, withdrawal of a trial device due to cardiac function recovery or exchange to other ventricular assist devices (VADs) for the purpose of bridge to transplantation (BTT) during 30 days after implantation will be considered study successes. For right ventricular assistance, withdrawal of tal device due to right ventricular function recovery within 30 days after implantation will be considered a study success. Secondary objectives include changes in brain natriuretic peptide levels (7 days after implantation of a trial device and the day of withdrawal of a trial device), period of mechanical ventricular support, changes in left ventricular ejection fraction (7 days after implantation of a trial device and the day of withdrawal of a trial device), and changes in left ventricular diastolic dimension (7 days after implantation of a trial device and the day of withdrawal of a trial device). We will disseminate the findings through regional, national, and international conferences and through peer-reviewed journals. UMIN Clinical Trials Registry (UMIN-CTR; R000033243) registered on 8 September 2017.

Analysis of Al2O3—parylene C bilayer coatings and impact of microelectrode topography on long term stability of implantable neural arrays

NASA Astrophysics Data System (ADS)

Caldwell, Ryan; Mandal, Himadri; Sharma, Rohit; Solzbacher, Florian; Tathireddy, Prashant; Rieth, Loren

2017-08-01

Objective. Performance of many dielectric coatings for neural electrodes degrades over time, contributing to loss of neural signals and evoked percepts. Studies using planar test substrates have found that a novel bilayer coating of atomic-layer deposited (ALD) Al2O3 and parylene C is a promising candidate for neural electrode applications, exhibiting superior stability to parylene C alone. However, initial results from bilayer encapsulation testing on non-planar devices have been less positive. Our aim was to evaluate ALD Al2O3-parylene C coatings using novel test paradigms, to rigorously evaluate dielectric coatings for neural electrode applications by incorporating neural electrode topography into test structure design. Approach. Five test devices incorporated three distinct topographical features common to neural electrodes, derived from the utah electrode array (UEA). Devices with bilayer (52 nm Al2O3  +  6 µm parylene C) were evaluated against parylene C controls (N  ⩾  6 per device type). Devices were aged in phosphate buffered saline at 67 °C for up to 311 d, and monitored through: (1) leakage current to evaluate encapsulation lifetimes (>1 nA during 5VDC bias indicated failure), and (2) wideband (1-105 Hz) impedance. Main results. Mean-times-to-failure (MTTFs) ranged from 12 to 506 d for bilayer-coated devices, versus 10 to  >2310 d for controls. Statistical testing (log-rank test, α  =  0.05) of failure rates gave mixed results but favored the control condition. After failure, impedance loss for bilayer devices continued for months and manifested across the entire spectrum, whereas the effect was self-limiting after several days, and restricted to frequencies  <100 Hz for controls. These results correlated well with observations of UEAs encapsulated with bilayer and control films. Significance. We observed encapsulation failure modes and behaviors comparable to neural electrode performance which were undetected in studies with planar test devices. We found the impact of parylene C defects to be exacerbated by ALD Al2O3, and conclude that inferior bilayer performance arises from degradation of ALD Al2O3 when directly exposed to saline. This is an important consideration, given that neural electrodes with bilayer coatings are expected to have ALD Al2O3 exposed at dielectric boundaries that delineate electrode sites. Process improvements and use of different inorganic coatings to decrease dissolution in physiological fluids may improve performance. Testing frameworks which take neural electrode complexities into account will be well suited to reliably evaluate such encapsulation schemes.

Accelerated life-test methods and results for implantable electronic devices with adhesive encapsulation.

PubMed

Huang, Xuechen; Denprasert, Petcharat May; Zhou, Li; Vest, Adriana Nicholson; Kohan, Sam; Loeb, Gerald E

2017-09-01

We have developed and applied new methods to estimate the functional life of miniature, implantable, wireless electronic devices that rely on non-hermetic, adhesive encapsulants such as epoxy. A comb pattern board with a high density of interdigitated electrodes (IDE) could be used to detect incipient failure from water vapor condensation. Inductive coupling of an RF magnetic field was used to provide DC bias and to detect deterioration of an encapsulated comb pattern. Diodes in the implant converted part of the received energy into DC bias on the comb pattern. The capacitance of the comb pattern forms a resonant circuit with the inductor by which the implant receives power. Any moisture affects both the resonant frequency and the Q-factor of the resonance of the circuitry, which was detected wirelessly by its effects on the coupling between two orthogonal RF coils placed around the device. Various defects were introduced into the comb pattern devices to demonstrate sensitivity to failures and to correlate these signals with visual inspection of failures. Optimized encapsulation procedures were validated in accelerated life tests of both comb patterns and a functional neuromuscular stimulator under development. Strong adhesive bonding between epoxy and electronic circuitry proved to be necessary and sufficient to predict 1 year packaging reliability of 99.97% for the neuromuscular stimulator.

Methodology for Physics and Engineering of Reliable Products

NASA Technical Reports Server (NTRS)

Cornford, Steven L.; Gibbel, Mark

1996-01-01

Physics of failure approaches have gained wide spread acceptance within the electronic reliability community. These methodologies involve identifying root cause failure mechanisms, developing associated models, and utilizing these models to inprove time to market, lower development and build costs and higher reliability. The methodology outlined herein sets forth a process, based on integration of both physics and engineering principles, for achieving the same goals.

75 FR 34156 - United States

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-16

... the package's failure. A failure of the package could expose the medical device to microbes, bacteria... research and development efforts, including, but not limited to, designs and experiments and the results of successful and unsuccessful designs and experiments; and (b) With respect to any intangible assets that are...

Quantifying Appropriate De-rating of SiC MOSFETs Subject to Cosmic Rays

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

Chatty, Kiran

Terrestrial Cosmic Radiation (TCR) is known to cause failures in high-voltage Si devices resulting in de-rating of the maximum reverse blocking voltage. In this work, a test setup was developed and unaccelerated TCR testing was performed on 1200V Si IGBTs, 1200V SiC MOSFETs and 1200V SiC Schottky diodes. Failures due to TCR were generated on 1200V Si IGBTs at reverse voltages from 900V to 1175V. Si IGBTs investigated in this work will need to be operated at a maximum voltage of 800V to achieve a Failure in Time (FIT) rate of 100. No failures were observed on 1200V SiC MOSFETsmore » and Schottky diodes after testing at 1200V for over 1.5 years demonstrating low FIT rates compared to Si IGBTs. 1200V SiC Schottky diodes were fabricated in this program and the packaged devices were used in the TCR testing.« less

Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications.

PubMed

Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

2013-03-01

Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

The total artificial heart.

PubMed

Cook, Jason A; Shah, Keyur B; Quader, Mohammed A; Cooke, Richard H; Kasirajan, Vigneshwar; Rao, Kris K; Smallfield, Melissa C; Tchoukina, Inna; Tang, Daniel G

2015-12-01

The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient's native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review.

How device-independent approaches change the meaning of physical theory

NASA Astrophysics Data System (ADS)

Grinbaum, Alexei

2017-05-01

Dirac sought an interpretation of mathematical formalism in terms of physical entities and Einstein insisted that physics should describe ;the real states of the real systems;. While Bell inequalities put into question the reality of states, modern device-independent approaches do away with the idea of entities: physical theory may contain no physical systems. Focusing on the correlations between operationally defined inputs and outputs, device-independent methods promote a view more distant from the conventional one than Einstein's 'principle theories' were from 'constructive theories'. On the examples of indefinite causal orders and almost quantum correlations, we ask a puzzling question: if physical theory is not about systems, then what is it about? Device-independent models suggest that physical theory can be 'about' languages.

21 CFR 890.5765 - Pressure-applying device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pressure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Pressure...

21 CFR 890.5765 - Presssure-applying device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Presssure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Presssure...

21 CFR 890.5765 - Pressure-applying device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pressure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Pressure...

21 CFR 890.5765 - Presssure-applying device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Presssure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Presssure...

21 CFR 890.5765 - Presssure-applying device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Presssure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Presssure...

Nanoscale wear as a stress-assisted chemical reaction

NASA Astrophysics Data System (ADS)

Jacobs, Tevis D. B.; Carpick, Robert W.

2013-02-01

Wear of sliding contacts leads to energy dissipation and device failure, resulting in massive economic and environmental costs. Typically, wear phenomena are described empirically, because physical and chemical interactions at sliding interfaces are not fully understood at any length scale. Fundamental insights from individual nanoscale contacts are crucial for understanding wear at larger length scales, and to enable reliable nanoscale devices, manufacturing and microscopy. Observable nanoscale wear mechanisms include fracture and plastic deformation, but recent experiments and models propose another mechanism: wear via atom-by-atom removal (`atomic attrition'), which can be modelled using stress-assisted chemical reaction kinetics. Experimental evidence for this has so far been inferential. Here, we quantitatively measure the wear of silicon--a material relevant to small-scale devices--using in situ transmission electron microscopy. We resolve worn volumes as small as 25 +/- 5 nm3, a factor of 103 lower than is achievable using alternative techniques. Wear of silicon against diamond is consistent with atomic attrition, and inconsistent with fracture or plastic deformation, as shown using direct imaging. The rate of atom removal depends exponentially on stress in the contact, as predicted by chemical rate kinetics. Measured activation parameters are consistent with an atom-by-atom process. These results, by direct observation, establish atomic attrition as the primary wear mechanism of silicon in vacuum at low loads.

All-inkjet-printed thin-film transistors: manufacturing process reliability by root cause analysis

PubMed Central

Sowade, Enrico; Ramon, Eloi; Mitra, Kalyan Yoti; Martínez-Domingo, Carme; Pedró, Marta; Pallarès, Jofre; Loffredo, Fausta; Villani, Fulvia; Gomes, Henrique L.; Terés, Lluís; Baumann, Reinhard R.

2016-01-01

We report on the detailed electrical investigation of all-inkjet-printed thin-film transistor (TFT) arrays focusing on TFT failures and their origins. The TFT arrays were manufactured on flexible polymer substrates in ambient condition without the need for cleanroom environment or inert atmosphere and at a maximum temperature of 150 °C. Alternative manufacturing processes for electronic devices such as inkjet printing suffer from lower accuracy compared to traditional microelectronic manufacturing methods. Furthermore, usually printing methods do not allow the manufacturing of electronic devices with high yield (high number of functional devices). In general, the manufacturing yield is much lower compared to the established conventional manufacturing methods based on lithography. Thus, the focus of this contribution is set on a comprehensive analysis of defective TFTs printed by inkjet technology. Based on root cause analysis, we present the defects by developing failure categories and discuss the reasons for the defects. This procedure identifies failure origins and allows the optimization of the manufacturing resulting finally to a yield improvement. PMID:27649784

Quality of Life for Saudi Patients With Heart Failure: A Cross-Sectional Correlational Study.

PubMed

AbuRuz, Mohannad Eid; Alaloul, Fawwaz; Saifan, Ahmed; Masa'deh, Rami; Abusalem, Said

2015-06-25

Heart failure is a major public health issue and a growing concern in developing countries, including Saudi Arabia. Most related research was conducted in Western cultures and may have limited applicability for individuals in Saudi Arabia. Thus, this study assesses the quality of life of Saudi patients with heart failure. A cross-sectional correlational design was used on a convenient sample of 103 patients with heart failure. Data were collected using the Short Form-36 and the Medical Outcomes Study-Social Support Survey. Overall, the patients' scores were low for all domains of Quality of Life. The Physical Component Summary and Mental Component Summary mean scores and SDs were (36.7±12.4, 48.8±6.5) respectively, indicating poor Quality of Life. Left ventricular ejection fraction was the strongest predictor of both physical and mental summaries. Identifying factors that impact quality of life for Saudi heart failure patients is important in identifying and meeting their physical and psychosocial needs.

Single-channel ground airborne radio system (SINCGARS) based remote control for the M1 Abrahms

NASA Astrophysics Data System (ADS)

Urda, Joseph R.

1995-04-01

Remote control of the Ml Abrahms Main Battle Tank through a minefield breach operation will remove the vehicle crew from the inherent hazard. A successful remote control system will provide automotive control yet not impair normal operation. This requires a minimum of physical parts, and an unobtrusive installation. Most importantly, a system failure must not impair the regular operation as a manned system. The system itself need not be complex. A minefield breach only requires simple control of automotive function and a mine plow interface. Control hardware for the Ml-Al can be reduced to two linear actuators, an electrical interface for the engine control unit, an interface for the mine plow, and the associated cables. Communication between vehicle control and operator control takes place over the vehicles organic radio (typically SINCGARS). This helps reduce the number of special purpose components for the remote control device. The device is currently awaiting an automotive safety test to prepare for its safety release. Because of the specific nature of the MDL-STD 1553-B data bus the device will not control an M1-A2 Main Battle Tank. The architecture will allow control of the M1-A2 through the 1553-B data bus however the physical hardware has not been constructed. The control scheme will not change. The communication interface will provide greater flexibility when interfacing to the vehicle tactical radio. Operational utility will be determined by U.S. Army Training and Doctrine Command personnel. The obvious benefit is that if a remote tank is lost during a minefield breach the crew is saved.

MO-G-BRE-02: A Survey of IMRT QA Practices for More Than 800 Institutions

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

Pulliam, K; Kerns, J; Howell, R

Purpose: A wide range of techniques and measurement devices are employed for IMRT QA, causing a large variation of accepted action limits and potential follow up for failing plans. Such procedures are not well established or accepted in the medical physics community. To achieve the goal of proving insight into current IMRT QA practices, we created an electronic IMRT QA survey. The survey was open to a variety of the most common QA devices and assessed the type of comparison to measurement, action limits, delivery methods, and clinical action for failing QA plans. Methods: We conducted an online survey throughmore » the Radiological Physics Center's (RPC) annual survey with the goal of ascertaining elements of routine patient-specific IMRT QA. A total of 874 institutions responded to the survey. The questions ranged from asking for action limits, dosimeter type(s) used, delivery techniques, and actions taken when a plan fails IMRT QA. Results: The most common (52%) planar gamma criteria was 3%/3 mm with a 95% of pixels passing criteria. The most common QA device were diode arrays (48%). The most common first response to a plan failing QA was to re-measure at the same point the point dose (89%), second was to re-measure at a new point (13%), and third was to analyze the plan in relative instead of absolute mode (10%) (Does not add to 100% as not all institutions placed a response for each QA follow-up option). Some institutions, however, claimed that they had never observed a plan failure. Conclusion: The survey provided insights into the way the community currently performs IMRT QA. This information will help in the push to standardize action limits among dosimeters.« less

Comparison of cyclic correlation algorithm implemented in matlab and python

NASA Astrophysics Data System (ADS)

Carr, Richard; Whitney, James

Simulation is a necessary step for all engineering projects. Simulation gives the engineers an approximation of how their devices will perform under different circumstances, without hav-ing to build, or before building a physical prototype. This is especially true for space bound devices, i.e., space communication systems, where the impact of system malfunction or failure is several orders of magnitude over that of terrestrial applications. Therefore having a reliable simulation tool is key in developing these devices and systems. Math Works Matrix Laboratory (MATLAB) is a matrix based software used by scientists and engineers to solve problems and perform complex simulations. MATLAB has a number of applications in a wide variety of fields which include communications, signal processing, image processing, mathematics, eco-nomics and physics. Because of its many uses MATLAB has become the preferred software for many engineers; it is also very expensive, especially for students and startups. One alternative to MATLAB is Python. The Python is a powerful, easy to use, open source programming environment that can be used to perform many of the same functions as MATLAB. Python programming environment has been steadily gaining popularity in niche programming circles. While there are not as many function included in the software as MATLAB, there are many open source functions that have been developed that are available to be downloaded for free. This paper illustrates how Python can implement the cyclic correlation algorithm and com-pares the results to the cyclic correlation algorithm implemented in the MATLAB environment. Some of the characteristics to be compared are the accuracy and precision of the results, and the length of the programs. The paper will demonstrate that Python is capable of performing simulations of complex algorithms such cyclic correlation.

Using Mobile Devices in Physical Education to Enhance Learning and Physical Activity for At-Risk Girls

ERIC Educational Resources Information Center

Gibbone, Anne; Perez, Samantha L.; Virgilio, Stephen J.

2014-01-01

The purpose of the article is to illustrate how a physical education program uses mobile devices to motivate at-risk girls attending an urban charter school. Permitting students to use mobile devices in physical education gives students a "technological freedom" that has been removed in other contexts. The apps described in this article…

21 CFR 890.5050 - Daily activity assist device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily activity...

21 CFR 890.5050 - Daily activity assist device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily activity...

21 CFR 890.5050 - Daily activity assist device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily activity...

21 CFR 890.5575 - Powered external limb overload warning device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Powered external limb overload warning device. 890.5575 Section 890.5575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890...

21 CFR 890.5575 - Powered external limb overload warning device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered external limb overload warning device. 890.5575 Section 890.5575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890...

21 CFR 890.5575 - Powered external limb overload warning device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Powered external limb overload warning device. 890.5575 Section 890.5575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890...

21 CFR 890.5050 - Daily activity assist device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily activity...

21 CFR 890.5575 - Powered external limb overload warning device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Powered external limb overload warning device. 890.5575 Section 890.5575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890...

21 CFR 890.5050 - Daily activity assist device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily activity...

21 CFR 890.5575 - Powered external limb overload warning device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Powered external limb overload warning device. 890.5575 Section 890.5575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890...

Implementation and reimbursement of remote monitoring for cardiac implantable electronic devices in Europe: a survey from the health economics committee of the European Heart Rhythm Association.

PubMed

Mairesse, Georges H; Braunschweig, Frieder; Klersy, Katherine; Cowie, Martin R; Leyva, Francisco

2015-05-01

Remote monitoring (RM) of cardiac implantable electronic devices (CIEDs) permits early detection of arrhythmias, device, and lead failure and may also be useful in risk-predicting patient-related outcomes. Financial benefits for patients and healthcare organizations have also been shown. We sought to assess the implementation and funding of RM of CIEDs, including conventional pacemakers (PMs), implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices in Europe. Electronic survey from 43 centres in 15 European countries. In the study sample, RM was available in 22% of PM patients, 74% of ICD patients, and 69% of CRT patients. The most significant perceived benefits were the early detection of atrial arrhythmias in pacemaker patients, lead failure in ICD patients, and worsening heart failure in CRT patients. Remote monitoring was reported to lead a reduction of in-office follow-ups for all devices. The most important reported barrier to the implementation of RM for all CIEDs was lack of reimbursement (80% of centres). Physicians regard RM of CIEDs as a clinically useful technology that affords significant benefits for patients and healthcare organizations. Remote monitoring, however, is perceived as increasing workload. Reimbursement for RM is generally perceived as a major barrier to implementation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Direct Left Atrial Pressure Monitoring in Severe Heart Failure: Long-Term Sensor Performance

PubMed Central

Ritzema, Jay; Eigler, Neal L.; Melton, Iain C.; Krum, Henry; Adamson, Philip B.; Kar, Saibal; Shah, Prediman K.; Whiting, James S.; Heywood, J. Thomas; Rosero, Spencer; Singh, Jagmeet P.; Saxon, Leslie; Matthews, Ray; Crozier, Ian G.; Abraham, William T.

2010-01-01

We report the stability, accuracy, and development history of a new left atrial pressure (LAP) sensing system in ambulatory heart failure (HF) patients. A total of 84 patients with advanced HF underwent percutaneous transseptal implantation of the pressure sensor. Quarterly noninvasive calibration by modified Valsalva maneuver was achieved in all patients, and 96.5% of calibration sessions were successful with a reproducibility of 1.2 mmHg. Absolute sensor drift was maximal after 3 months at 4.7 mmHg (95% CI, 3.2–6.2 mmHg) and remained stable through 48 months. LAP was highly correlated with simultaneous pulmonary wedge pressure at 3 and 12 months (r = 0.98, average difference of 0.8 ± 4.0 mmHg). Freedom from device failure was 95% (n = 37) at 2 years and 88% (n = 12) at 4 years. Causes of failure were identified and mitigated with 100% freedom from device failure and less severe anomalies in the last 41 consecutive patients (p = 0.005). Accurate and reliable LAP measurement using a chronic implanted monitoring system is safe and feasible in patients with advanced heart failure. PMID:20945124

NHLBI’s Program for VAD Therapy for Moderately Advanced Heart Failure: The REVIVE-IT Pilot Trial

PubMed Central

Baldwin, J. Timothy; Mann, Douglas L.

2010-01-01

Background VADs are used to bridge heart failure patients to transplantation, to allow their own hearts to recover, or as permanent (“destination”) therapy. To date, the use of VADs has been limited to late-stage heart failure patients because of the associated device risks. In 2008, an NHLBI working group met to evaluate the treatment of heart failure using VADs and to advise the institute on how therapy for heart failure may be best advanced by clinical trials involving the devices. Discussion and Recommendations Recognizing the improvements in VAD technology and in patient care and selection over the past decade, the working group recommended that a trial be performed to assess the use of chronic VAD therapy in patients who are less ill than those currently eligible for destination therapy. The hypothesis proposed for the trial is that VAD therapy may improve both survival and quality of life in moderately advanced heart failure patients who are neither inotrope-dependent nor exercise-intolerant and have not yet developed serious consequences such as malnourishment, end-organ damage, and immobility. Based on the group’s recommendations, NHLBI issued an RFP in 2009 for the REVIVE-IT Pilot Trail which will serve to test the hypothesis and inform the pivotal trial. PMID:21055648

Reliability of vapor-grown planar In/sub 0. 53/Ga/sub 0. 47/As/InP p-i-n photodiodes with very high failure activation energy

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

Forrest, S.R.; Ban, V.S.; Gasparian, G.

1988-05-01

The authors measured the mean time to failure (MTTF) for a statistically significant population of planar In/sub 0.53/Ga/sub 0.47/As/InP heterostructure p-i-n photodetectors at several elevated temperatures. The probability for failure is fit to a log-normal distribution, with the result that the width of the failure distribution is sigma = 0.55 +- 0.2, and is roughly independent of temperature. From the temperature dependence of the MTFF data, they find that the failure mechanism is thermally activated, with an activation energy of 1.5 +- 0.2 eV measured in the temperature range of 170 - 250/sup 0/C. This extrapolates to a MTTF ofmore » less than 0.1 failure in 10/sup 9/ h (or < 0.1 FIT) at 70/sup 0/C, indicating that such devices are useful for systems requiring extremely high reliable components, even if operated at elevated temperatures for significant time periods. To the authors' knowledge, this activation energy is the highest value reported for In/sub 0.53/Ga/sub 0.47/As/InP photodetectors, and is significantly higher than the energies of -- 0.85 eV often suspected to these devices.« less

Microwave evaluation of electromigration susceptibility in advanced interconnects

NASA Astrophysics Data System (ADS)

Sunday, Christopher E.; Veksler, Dmitry; Cheung, Kin C.; Obeng, Yaw S.

2017-11-01

Traditional metrology has been unable to adequately address the needs of the emerging integrated circuits (ICs) at the nano scale; thus, new metrology and techniques are needed. For example, the reliability challenges in fabrication need to be well understood and controlled to facilitate mass production of through-substrate-via (TSV) enabled three-dimensional integrated circuits (3D-ICs). This requires new approaches to the metrology. In this paper, we use the microwave propagation characteristics to study the reliability issues that precede the physical damage caused by electromigration in the Cu-filled TSVs. The pre-failure microwave insertion losses and group delay are dependent on both the device temperature and the amount of current forced through the devices-under-test. The microwave insertion losses increase with the increase in the test temperature, while the group delay increases with the increase in the forced direct current magnitude. The microwave insertion losses are attributed to the defect mobility at the Cu-TiN interface, and the group delay changes are due to resistive heating in the interconnects, which perturbs the dielectric properties of the cladding dielectrics of the copper fill in the TSVs.

Evaluation of commercial ADC radiation tolerance for accelerator experiments

DOE PAGES

Chen, K.; Chen, H.; Kierstead, J.; ...

2015-08-17

Electronic components used in high energy physics experiments are subjected to a radiation background composed of high energy hadrons, mesons and photons. These particles can induce permanent and transient effects that affect the normal device operation. Ionizing dose and displacement damage can cause chronic damage which disable the device permanently. Transient effects or single event effects are in general recoverable with time intervals that depend on the nature of the failure. The magnitude of these effects is technology dependent with feature size being one of the key parameters. Analog to digital converters are components that are frequently used in detectormore » front end electronics, generally placed as close as possible to the sensing elements to maximize signal fidelity. We report on radiation effects tests conducted on 17 commercially available analog to digital converters and extensive single event effect measurements on specific twelve and fourteen bit ADCs that presented high tolerance to ionizing dose. We discuss mitigation strategies for single event effects (SEE) for their use in the large hadron collider environment.« less

Privacy and security of patient data in the pathology laboratory.

PubMed

Cucoranu, Ioan C; Parwani, Anil V; West, Andrew J; Romero-Lauro, Gonzalo; Nauman, Kevin; Carter, Alexis B; Balis, Ulysses J; Tuthill, Mark J; Pantanowitz, Liron

2013-01-01

Data protection and security are critical components of routine pathology practice because laboratories are legally required to securely store and transmit electronic patient data. With increasing connectivity of information systems, laboratory work-stations, and instruments themselves to the Internet, the demand to continuously protect and secure laboratory information can become a daunting task. This review addresses informatics security issues in the pathology laboratory related to passwords, biometric devices, data encryption, internet security, virtual private networks, firewalls, anti-viral software, and emergency security situations, as well as the potential impact that newer technologies such as mobile devices have on the privacy and security of electronic protected health information (ePHI). In the United States, the Health Insurance Portability and Accountability Act (HIPAA) govern the privacy and protection of medical information and health records. The HIPAA security standards final rule mandate administrative, physical, and technical safeguards to ensure the confidentiality, integrity, and security of ePHI. Importantly, security failures often lead to privacy breaches, invoking the HIPAA privacy rule as well. Therefore, this review also highlights key aspects of HIPAA and its impact on the pathology laboratory in the United States.

Intraosseous access in the military operational setting.

PubMed

Vassallo, J; Horne, S; Smith, J E

2014-01-01

In an operational military environment, circulatory access can prove difficult for a variety of reasons including profound hypovolaemia, and limited first responder experience. With many injuries that cause catastrophic haemorrhage, such as traumatic limb amputations, circulatory access is needed as quickly as possible. Since 2006, the Defence Medical Services have been using the EZ-IO and FAST1 devices as a means of obtaining circulatory access. A prospective observational study was conducted between March and July 2011 at the Emergency Department, Camp Bastion, Afghanistan. All patients with an intraosseous device had data recorded that included if the device successfully flushed (functionality) and if any problems were encountered. 117 patients presented with a total of 195 devices: 149 were EZ-IO (76%) and 46 were FAST1 (24%). Functionality was recorded for 111 (57%), with 17 failing to function, yielding an overall success rate of 84.7%. Device failure was observed to be more prevalent in the humerus; inability to flush the device was the leading cause, followed by mechanical failure. There were 2 complications, device breaking on removal being the reason for both. The devices in the study were tested for a period of time following insertion (median 32 minutes), and still the success rates mirror those found in the literature. Observed differences between sites were not found to be significant with confidence intervals overlapping. Further work is proposed to investigate the long-term complications of intraosseous devices.

Rocket Engine Oscillation Diagnostics

NASA Technical Reports Server (NTRS)

Nesman, Tom; Turner, James E. (Technical Monitor)

2002-01-01

Rocket engine oscillating data can reveal many physical phenomena ranging from unsteady flow and acoustics to rotordynamics and structural dynamics. Because of this, engine diagnostics based on oscillation data should employ both signal analysis and physical modeling. This paper describes an approach to rocket engine oscillation diagnostics, types of problems encountered, and example problems solved. Determination of design guidelines and environments (or loads) from oscillating phenomena is required during initial stages of rocket engine design, while the additional tasks of health monitoring, incipient failure detection, and anomaly diagnostics occur during engine development and operation. Oscillations in rocket engines are typically related to flow driven acoustics, flow excited structures, or rotational forces. Additional sources of oscillatory energy are combustion and cavitation. Included in the example problems is a sampling of signal analysis tools employed in diagnostics. The rocket engine hardware includes combustion devices, valves, turbopumps, and ducts. Simple models of an oscillating fluid system or structure can be constructed to estimate pertinent dynamic parameters governing the unsteady behavior of engine systems or components. In the example problems it is shown that simple physical modeling when combined with signal analysis can be successfully employed to diagnose complex rocket engine oscillatory phenomena.

A cloud-based home management system for patients with a left ventricular assist device: a case report.

PubMed

Nomoto, Shinichi; Utsumi, Momoe; Minakata, Kenji

2016-07-04

Since implantable left ventricular assist devices (LVAD) with smaller configurations became available for bridge-to-transplant or even destination therapy in patients with end-stage heart failure, an increasing number of patients with these devices are receiving home medical management. However, these patients may be anxious about potential complications such as pump failure, thromboembolism, and infections that may occur during home management. To provide a sense of security during home management of patients with LVAD and to establish an ideal shared-care system, we developed a patient-centered cloud-based home management system for patients with LVAD. In this case report, we describe this system and report a trial of it in a 64-year-old patient with an LVAD.

Explanting the Nellix Endovascular Aortic Sealing Endoprosthesis for Proximal Aortic Neck Failure.

PubMed

Lee, Cheong Jun; Cuff, Robert

2018-05-17

Open conversion following endovascular aortic repair (EVAR) has inherent challenges particular to the device being explanted. The Nellix endograft is unlike any other device as it utilizes polymer filling of endobags within the aorto-iliac lumen to seal the AAA sac; a developing concept known as endovascular aortic sealing (EVAS). Conversion to open repair of AAA treated with the Nellix endograft have rarely been discussed. Explants that have been previously reported were for graft infection. We present two Nellix graft explants that were required for device migration and subsequent development of a type IA endoleak. The technique and nuances observed during open conversion of this novel endograft for proximal aortic neck failure is described in this report. Copyright © 2018. Published by Elsevier Inc.

Reliability improvement of 1 mil aluminum wire bonds for semiconductors, technical performance summary

NASA Technical Reports Server (NTRS)

1971-01-01

The reliability of semiconductor devices as influenced by the reliability of wire bonds used in the assembly of the devices is investigated. The specific type of failure dealt with involves fracture of wire bonds as a result of repeated flexure of the wire at the heel of the bond when the devices are operated in an on-off mode. The mechanism of failure is one of induced fracture of the wire. To improve the reliability of a chosen transistor, one-mil diameter wires of aluminum with various alloy additions were studied using an accelerated fatigue testing machine. In addition, the electroprobe was used to study the metallurgy of the wires as to microstructure and kinetics of the growth of insoluble phases. Thermocompression and ultrasonic bonding techniques were also investigated.

49 CFR 220.38 - Communication equipment failure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.38 Communication equipment failure. (a) Any radio or wireless communication device found not to be... other employee designated by the railroad shall be so notified as soon as practicable. (b) If a radio or...

49 CFR 220.38 - Communication equipment failure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.38 Communication equipment failure. (a) Any radio or wireless communication device found not to be... other employee designated by the railroad shall be so notified as soon as practicable. (b) If a radio or...

49 CFR 220.38 - Communication equipment failure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.38 Communication equipment failure. (a) Any radio or wireless communication device found not to be... other employee designated by the railroad shall be so notified as soon as practicable. (b) If a radio or...

14 CFR 25.629 - Aeroelastic stability requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... propeller or rotating device that contributes significant dynamic forces. Compliance with this section must...) Any single failure in any flutter damper system. (3) For airplanes not approved for operation in icing... dynamic forces, any single failure of the engine structure that would reduce the rigidity of the...

Inexpensive Device for Demonstrating Rock Slope Failure and Other Collapse Phenomena.

ERIC Educational Resources Information Center

Stimpson, B.

1980-01-01

Describes an inexpensive modeling technique for demonstrating large-scale displacement phenomena in rock masses, such as slope collapse and failure of underground openings. Excavation of the model material occurs through openings made in the polyurethane foam in the correct excavation sequence. (Author/SA)

Reliability Modeling of Microelectromechanical Systems Using Neural Networks

NASA Technical Reports Server (NTRS)

Perera. J. Sebastian

2000-01-01

Microelectromechanical systems (MEMS) are a broad and rapidly expanding field that is currently receiving a great deal of attention because of the potential to significantly improve the ability to sense, analyze, and control a variety of processes, such as heating and ventilation systems, automobiles, medicine, aeronautical flight, military surveillance, weather forecasting, and space exploration. MEMS are very small and are a blend of electrical and mechanical components, with electrical and mechanical systems on one chip. This research establishes reliability estimation and prediction for MEMS devices at the conceptual design phase using neural networks. At the conceptual design phase, before devices are built and tested, traditional methods of quantifying reliability are inadequate because the device is not in existence and cannot be tested to establish the reliability distributions. A novel approach using neural networks is created to predict the overall reliability of a MEMS device based on its components and each component's attributes. The methodology begins with collecting attribute data (fabrication process, physical specifications, operating environment, property characteristics, packaging, etc.) and reliability data for many types of microengines. The data are partitioned into training data (the majority) and validation data (the remainder). A neural network is applied to the training data (both attribute and reliability); the attributes become the system inputs and reliability data (cycles to failure), the system output. After the neural network is trained with sufficient data. the validation data are used to verify the neural networks provided accurate reliability estimates. Now, the reliability of a new proposed MEMS device can be estimated by using the appropriate trained neural networks developed in this work.

Results following implantation of mechanical circulatory support systems: The Montreal Heart Institute experience

PubMed Central

El-Hamamsy, Ismaïl; Jacques, Frédéric; Perrault, Louis P; Bouchard, Denis; Demers, Philippe; White, Michel; Pelletier, Guy B; Racine, Normand; Pellerin, Michel; Carrier, Michel

2009-01-01

BACKGROUND: Mechanical circulatory support systems (MCSS) have been available in Canada since 1986. Accepted indications include bridging to transplantation or recovery. The present study reviewed the results following MCSS implantation at the Montreal Heart Institute (Montreal, Quebec). METHODS: From September 1987 to September 2006, 43 MCSS were implanted (32 Thoratec [Thoratec Corporation, USA], nine Cardio West TAH [SynCardia Systems Inc, USA], two Novacor [World Heart Corporation, Canada]) in 43 patients (mean [± SD] age 44±13 years; range 19 to 64 years). Indications for implantation included cardiogenic shock due to ischemic (n=19), viral (n=10) or other types of cardiomyopathies (n=14). RESULTS: The mean ejection fraction before implantation was 17.6±6.5% (range 10% to 45%). Before MCSS implantation, most patients showed signs of end-organ failure, including mechanical ventilation (77%), central venous pressure higher than 16 mmHg (44%), oliguria (35%) and hepatic dysfunction (19%). The mean duration of MCSS support was 22.8±32.8 days (range one to 158 days). Survival to transplantation or recovery was 74%. Only one patient was successfully bridged to recovery. Complications were common during MCSS support. They included re-exploration for bleeding (47%), respiratory failure (44%), renal failure requiring temporary dialysis (40%), infection (33%) and neurological events (16%). Only one patient had device failure. In patients successfully bridged to transplantation, early actuarial survival (one month) following transplantation averaged 71±8% and was 57±9% at one year. CONCLUSION: MCSS support with a left ventricular assist device or a total artificial heart provides an effective means of bridging terminally ill patients to transplantation or recovery. Early survival after transplantation shows satisfactory results. However, these results come at the expense of frequent device-related complications, and device failure remains a constant threat. PMID:19214294

Reliability improvement of wire bonds subjected to fatigue stresses.

NASA Technical Reports Server (NTRS)

Ravi, K. V.; Philofsky, E. M.

1972-01-01

The failure of wire bonds due to repeated flexure when semiconductor devices are operated in an on-off mode has been investigated. An accelerated fatigue testing apparatus was constructed and the major fatigue variables, aluminum alloy composition, and bonding mechanism, were tested. The data showed Al-1% Mg wires to exhibit superior fatigue characteristics compared to Al-1% Cu or Al-1% Si and ultrasonic bonding to be better than thermocompression bonding for fatigue resistance. Based on these results highly reliable devices were fabricated using Al-1% Mg wire with ultrasonic bonding which withstood 120,000 power cycles with no failures.

Prediction of Lumen Output and Chromaticity Shift in LEDs Using Kalman Filter and Extended Kalman Filter Based Models

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

Lall, Pradeep; Wei, Junchao; Davis, J Lynn

2014-06-24

Abstract— Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. Traditional light sources “burn out” at end-of-life. For an incandescent bulb, the lamp life ismore » defined by B50 life. However, the LEDs have no filament to “burn”. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. Presently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. The underlying TM-21 Model may not capture the failure physics in presence of multiple failure mechanisms. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed. In this paper, Kalman Filter (KF) and Extended Kalman Filters (EKF) have been used to develop a 70-percent Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. Ten-thousand hour LM-80 test data for various LEDs have been used for model development. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. Life prediction of L70 life for the LEDs used in SSL luminaires from KF and EKF based models have been compared with the TM-21 model predictions and experimental data.« less

Child Neglect in the Military Community: Are We Neglecting the Child?

DTIC Science & Technology

1995-04-01

encompasses "a parent’s or other caretaker’s failure to provide basic physical health care, supervision, nutrition, personal hygiene, emotional nurturing...the term "child neglect" generally refers to: emotional neglect, abandonment, and the failure to provide: food, shelter, clothing, medical care...Resource Center on Child Abuse and Neglect 26-- divides child neglect into four types: physical, educational, emotional , and medical. Physical neglect

An in-depth, longitudinal examination of the daily physical activity of a patient with heart failure using a Nintendo Wii at home: a case report.

PubMed

Klompstra, Leonie Verheijden; Jaarsma, Tiny; Strömberg, Anna

2013-06-01

To explore the influence of the Nintendo Wii on the daily physical activity of a patient with chronic heart failure at home. A 74-year-old Swedish patient with heart failure had access to a Nintendo Wii at home for 12 weeks. Exercise motivation, exercise self-efficacy and exercise capacity were assessed before and after the intervention. Data on perceived physical effort, global well-being and expended energy were collected every day during the intervention. During the 12 weeks of access to the Nintendo Wii, daily physical activity increased by 200% on weekdays and 57% on weekends, compared with baseline. The patient's exercise motivation and exercise self-efficacy increased during the study, whereas perceived physical effort and global well-being did not change. The patient had no difficulties in using the system and did not suffer any major harm. The results of this case study suggest that providing patients with heart failure access to a Nintendo Wii is a promising and safe intervention. The energy expended by the patient per day increased, as did exercise capacity. Playing the Nintendo Wii did not increase the perceived physical effort, but increased motivation to exercise and decreased barriers to exercising.

75 FR 44267 - Draft Guidance for Industry and Food and Drug Administration Staff; Medical Devices; Neurological...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-28

... Physical Medicine Device Guidance Document; Reopening of Comment Period AGENCY: Food and Drug... for 11 neurological and physical medicine devices. FDA is reopening the comment period to allow... announcing the availability of draft special controls guidance documents for 11 neurological and physical...

The failure of earthquake failure models

USGS Publications Warehouse

Gomberg, J.

2001-01-01

In this study I show that simple heuristic models and numerical calculations suggest that an entire class of commonly invoked models of earthquake failure processes cannot explain triggering of seismicity by transient or "dynamic" stress changes, such as stress changes associated with passing seismic waves. The models of this class have the common feature that the physical property characterizing failure increases at an accelerating rate when a fault is loaded (stressed) at a constant rate. Examples include models that invoke rate state friction or subcritical crack growth, in which the properties characterizing failure are slip or crack length, respectively. Failure occurs when the rate at which these grow accelerates to values exceeding some critical threshold. These accelerating failure models do not predict the finite durations of dynamically triggered earthquake sequences (e.g., at aftershock or remote distances). Some of the failure models belonging to this class have been used to explain static stress triggering of aftershocks. This may imply that the physical processes underlying dynamic triggering differs or that currently applied models of static triggering require modification. If the former is the case, we might appeal to physical mechanisms relying on oscillatory deformations such as compaction of saturated fault gouge leading to pore pressure increase, or cyclic fatigue. However, if dynamic and static triggering mechanisms differ, one still needs to ask why static triggering models that neglect these dynamic mechanisms appear to explain many observations. If the static and dynamic triggering mechanisms are the same, perhaps assumptions about accelerating failure and/or that triggering advances the failure times of a population of inevitable earthquakes are incorrect.

Ethical challenges of deactivation of cardiac devices in advanced heart failure.

PubMed

Chamsi-Pasha, Hassan; Chamsi-Pasha, Mohammed A; Albar, Mohammed Ali

2014-06-01

More than 23 million adults worldwide have heart failure (HF). Although survival after heart failure diagnosis has improved over time, mortality from heart failure remains high. At the end of life, the chronic HF patient often becomes increasingly symptomatic, and may have other life-limiting comorbidities as well. Multiple trials have shown a clear mortality benefit with the use of implantable cardioverter defibrillators (ICDs) in patients with cardiomyopathy and ventricular arrhythmia. However, patients who have an ICD may be denied the chance of a sudden cardiac death, and instead are committed to a slower terminal decline, with frequent DC shocks that can be painful and decrease the quality of life, greatly contributing to their distress and that of their families during this period. While patients with ICDs are routinely counseled with regard to the benefits of ICDs, they have a poor understanding of the options for device deactivation and related ethical and legal implications. Deactivating an ICD or not performing a generator change is both legal and ethical, and is supported by guidelines from both sides of the Atlantic. Patient autonomy is paramount, and no patient is committed to any therapy that they no longer wish to receive. Left ventricular assist devices (LVADs) were initially used as bridge in patients awaiting heart transplantation, but they are currently implanted as destination therapy (DT) in patients with end-stage heart failure who have failed to respond to optimal medical therapy and who are ineligible for cardiac transplantation. The decision-making process for initiation and deactivation of LVAD is becoming more and more ethically and clinically challenging, particularly for elderly patients.

Challenges on non-invasive ventilation to treat acute respiratory failure in the elderly.

PubMed

Scala, Raffaele

2016-11-15

Acute respiratory failure is a frequent complication in elderly patients especially if suffering from chronic cardio-pulmonary diseases. Non-invasive mechanical ventilation constitutes a successful therapeutic tool in the elderly as, like in younger patients, it is able to prevent endotracheal intubation in a wide range of acute conditions; moreover, this ventilator technique is largely applied in the elderly in whom invasive mechanical ventilation is considered not appropriated. Furthermore, the integration of new technological devices, ethical issues and environment of treatment are still largely debated in the treatment of acute respiratory failure in the elderly.This review aims at reporting and critically analyzing the peculiarities in the management of acute respiratory failure in elderly people, the role of noninvasive mechanical ventilation, the potential advantages of applying alternative or integrated therapeutic tools (i.e. high-flow nasal cannula oxygen therapy, non-invasive and invasive cough assist devices and low-flow carbon-dioxide extracorporeal systems), drawbacks in physician's communication and "end of life" decisions. As several areas of this topic are not supported by evidence-based data, this report takes in account also "real-life" data as well as author's experience.The choice of the setting and of the timing of non-invasive mechanical ventilation in elderly people with advanced cardiopulmonary disease should be carefully evaluated together with the chance of using integrated or alternative supportive devices. Last but not least, economic and ethical issues may often challenges the behavior of the physicians towards elderly people who are hospitalized for acute respiratory failure at the end stage of their cardiopulmonary and neoplastic diseases.

A Novel Method to Assess Wear Rates of Retrieved Tibial Inserts Following in-vivo Use

NASA Astrophysics Data System (ADS)

Paniogue, Tanille J.

Ultra-high molecular weight polyethylene (UHMWPE) on cobalt chrome is the bearing couple of choice for total knee arthroplasty. The number of patients undergoing total knee arthroplasty has been steadily growing and is projected to continue increasing rapidly in the near future. Many of these patients are younger and more active and therefore need a longer lasting device. However, many of these devices fail prematurely and often the primary reason for failure and ultimately revision is due to wear related issues. Therefore, examining how wear rates of the UHMWPE tibial insert change during in-vivo use can help elucidate the mechanisms of accelerated wear and hopefully aid in finding solutions to combat wear related failures. Different crosslinking treatments have been employed by manufacturers to improve wear resistance of the polyethylene. While this has been shown to be an effective way to reduce wear, crosslinking has led to other issues such as oxidative instability and a decline in mechanical properties. The purpose of this body of work is to examine how changes in oxidation, after in-vivo use, affect wear resistance. A novel testing method was developed to test the native articular surface from retrieved tibial inserts in a laboratory Pin-on-Disk (POD) simulator. The method was validated using short-duration implant articular surfaces and non-articular control pins. In the absence of high surface oxidation or severe surface damage, the articular surface pins had comparable steady state wear rates to their bulk counterparts. Tests of devices with longer in-vivo service show chemical changes consistent with a free-radical mediated oxidation mechanism. Tribological assessment of the articular surfaces shows increasing wear rates as a function of oxidation. While this relationship has been hypothesized in the literature, these experiments represent the first physical demonstration of the phenomenon. The wear mechanism is further explored through infrared spectroscopy, assessment of the wear scar, and documentation of evolution of the contact surfaces in the articulation.

Digital Devices and Teaching the Whole Student: Developing and Validating an Instrument to Measure Educators' Attitudes and Beliefs

ERIC Educational Resources Information Center

Cho, Vincent; Littenberg-Tobias, Joshua

2016-01-01

Even as digital devices (e.g., tablets, smart phones, laptops) have become increasingly ubiquitous in schools, concerns have also been raised that such devices might hinder students' social, emotional, and personal development. Educators' perspectives on such matters could shape the success or failure of 1:1 technology initiatives. Thus, there is…

21 CFR 890.1375 - Diagnostic electromyograph.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1375 Diagnostic..., and to monitor and display the electrical activity produced by nerves, for the diagnosis and prognosis...

Recommendations for pacemaker implantation for the treatment of atrial tachyarrhythmias and resynchronisation therapy for heart failure

PubMed Central

van Hemel, N.M.; Dijkman, B.; de Voogt, W.G.; Beukema, W.P.; Bosker, H.A.; de Cock, C.C.; Jordaens, L.J.L.M.; van Gelder, I.C.; van Gelder, L.M.; van Mechelen, R.; Ruiter, J.H.; Sedney, M.I.; Slegers, L.C.

2004-01-01

Today, new pacing algorithms and stimulation methods for the prevention and interruption of atrial tachyarrhythmias can be applied on patients who need bradycardia pacing for conventional reasons. In addition, biventricular pacing as additive treatment for patients with severe congestive heart failure due to ventricular systolic dysfunction and prolonged intraventricular conduction has shown to improve symptoms and reduce hospital admissions. These new pacing technologies and the optimising of the pacing programmes are complex, expensive and time-consuming. Based on many clinical studies the indications for these devices are beginning to emerge. To support the cardiologist's decision-making and to prevent waste of effort and resources, the 'ad hoc committee' has provided preliminary recommendations for implantable devices to treat atrial tachyarrhythmias and to extend the treatment of congestive heart failure respectively. PMID:25696255

An evaluation of gap-filled Landsat SLC-off imagery for wildland fire burn severity mapping

USGS Publications Warehouse

Howard, Stephen M.; Lacasse, James M.

2004-01-01

n May 31, 2003 unusual artifacts appeared within image data collected by the Enhanced Thematic Mapper plus (ETM+) instrument on-board the Landsat 7 spacecraft. The U.S. Geological Survey (USGS), with the support of NASA, has been working to find a means of compensating for the data gaps that result from a failure of the instrument’s scan line corrector (SLC). The SLC is an electromechanical device that compensates for the forward motion of the spacecraft by modifying the instrument’s optical path. The problem is likely due to a mechanical failure of the device for which there is no redundancy and that cannot be repaired or coaxed back into service. Further information regarding Landsat 7 and the SLC failure can be found at the Landsat Project home page (http://landsat7.usgs.gov).

Reliability evaluation of CMOS RAMs

NASA Astrophysics Data System (ADS)

Salvo, C. J.; Sasaki, A. T.

The results of an evaluation of the reliability of a 1K x 1 bit CMOS RAM and a 4K x 1 bit CMOS RAM for the USAF are reported. The tests consisted of temperature cycling, thermal shock, electrical overstress-static discharge and accelerated life test cells. The study indicates that the devices have high reliability potential for military applications. Use-temperature failure rates at 100 C were 0.54 x 10 to the -5th failures/hour for the 1K RAM and 0.21 x 10 to the -5th failures/hour for the 4K RAM. Only minimal electrostatic discharge damage was noted in the devices when they were subjected to multiple pulses at 1000 Vdc, and redesign of the 7 Vdc quiescent parameter of the 4K RAM is expected to raise its field threshold voltage.

Prologue: ventricular assist devices and total artificial hearts. A historical perspective.

PubMed

Frazier, O H

2003-02-01

In the 1960s, when LVADs and TAHs were introduced into clinical use, researchers estimated that, with this technology, the problem of heart failure could be solved within 20 years. Unfortunately, the evolution of these devices has taken much longer than anticipated. Nevertheless, significant advances have been achieved in both cardiac assistance and replacement, and today's cardiac surgeons have a wide range of devices from which to choose (Table 4). This progress has largely been due to the support of the NHLBI, especially the Devices and Technology Division headed by John Watson, and of the devoted commitment of the investigators. Because of the long-term commitment required for both basic and clinical research, commercial medical technology companies are unable to assume this burden. Advances in mechanical circulatory support and replacement have benefited numerous patients worldwide who would otherwise have died of heart failure, and devices now exist for use as bridges to recovery, bridges to transplant, and destination therapy. The current challenge is to refine what we have and to apply these technologies to broader patient populations with maximal safety and at a reasonable cost.

The autonomic nervous system as a therapeutic target in heart failure: a scientific position statement from the Translational Research Committee of the Heart Failure Association of the European Society of Cardiology.

PubMed

van Bilsen, Marc; Patel, Hitesh C; Bauersachs, Johann; Böhm, Michael; Borggrefe, Martin; Brutsaert, Dirk; Coats, Andrew J S; de Boer, Rudolf A; de Keulenaer, Gilles W; Filippatos, Gerasimos S; Floras, John; Grassi, Guido; Jankowska, Ewa A; Kornet, Lilian; Lunde, Ida G; Maack, Christoph; Mahfoud, Felix; Pollesello, Piero; Ponikowski, Piotr; Ruschitzka, Frank; Sabbah, Hani N; Schultz, Harold D; Seferovic, Petar; Slart, Riemer H J A; Taggart, Peter; Tocchetti, Carlo G; Van Laake, Linda W; Zannad, Faiez; Heymans, Stephane; Lyon, Alexander R

2017-11-01

Despite improvements in medical therapy and device-based treatment, heart failure (HF) continues to impose enormous burdens on patients and health care systems worldwide. Alterations in autonomic nervous system (ANS) activity contribute to cardiac disease progression, and the recent development of invasive techniques and electrical stimulation devices has opened new avenues for specific targeting of the sympathetic and parasympathetic branches of the ANS. The Heart Failure Association of the European Society of Cardiology recently organized an expert workshop which brought together clinicians, trialists and basic scientists to discuss the ANS as a therapeutic target in HF. The questions addressed were: (i) What are the abnormalities of ANS in HF patients? (ii) What methods are available to measure autonomic dysfunction? (iii) What therapeutic interventions are available to target the ANS in patients with HF, and what are their specific strengths and weaknesses? (iv) What have we learned from previous ANS trials? (v) How should we proceed in the future? © 2017 The Authors. European Journal of Heart Failure © 2017 European Society of Cardiology.

Accuracy of Seattle Heart Failure Model and HeartMate II Risk Score in Non-Inotrope-Dependent Advanced Heart Failure Patients: Insights From the ROADMAP Study (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients).

PubMed

Lanfear, David E; Levy, Wayne C; Stehlik, Josef; Estep, Jerry D; Rogers, Joseph G; Shah, Keyur B; Boyle, Andrew J; Chuang, Joyce; Farrar, David J; Starling, Randall C

2017-05-01

Timing of left ventricular assist device (LVAD) implantation in advanced heart failure patients not on inotropes is unclear. Relevant prediction models exist (SHFM [Seattle Heart Failure Model] and HMRS [HeartMate II Risk Score]), but use in this group is not established. ROADMAP (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Ambulatory Heart Failure Patients) is a prospective, multicenter, nonrandomized study of 200 advanced heart failure patients not on inotropes who met indications for LVAD implantation, comparing the effectiveness of HeartMate II support versus optimal medical management. We compared SHFM-predicted versus observed survival (overall survival and LVAD-free survival) in the optimal medical management arm (n=103) and HMRS-predicted versus observed survival in all LVAD patients (n=111) using Cox modeling, receiver-operator characteristic (ROC) curves, and calibration plots. In the optimal medical management cohort, the SHFM was a significant predictor of survival (hazard ratio=2.98; P <0.001; ROC area under the curve=0.71; P <0.001) but not LVAD-free survival (hazard ratio=1.41; P =0.097; ROC area under the curve=0.56; P =0.314). SHFM showed adequate calibration for survival but overestimated LVAD-free survival. In the LVAD cohort, the HMRS had marginal discrimination at 3 (Cox P =0.23; ROC area under the curve=0.71; P =0.026) and 12 months (Cox P =0.036; ROC area under the curve=0.62; P =0.122), but calibration was poor, underestimating survival across time and risk subgroups. In non-inotrope-dependent advanced heart failure patients receiving optimal medical management, the SHFM was predictive of overall survival but underestimated the risk of clinical worsening and LVAD implantation. Among LVAD patients, the HMRS had marginal discrimination and underestimated survival post-LVAD implantation. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01452802. © 2017 American Heart Association, Inc.

Improving proximal fixation and seal with the HeliFx Aortic EndoAnchor.

PubMed

Deaton, David H

2012-12-01

Endovascular aneurysm repair (EVAR) transformed the therapy for aortic aneurysms and introduced an era of widespread use for endovascular procedures in a variety of vascular beds. Although dramatic improvements in acute outcomes drove the early enthusiasm for EVAR, a realization that the long-term integrity of the endoprostheses used for EVAR were sometimes inferior to the results obtained with open surgical reconstruction dampened enthusiasm for their use in low-risk and younger patients who mandated long-term follow-up. While early EVAR failure modes are often related to technical aspects of the implantation, late failures are often related to the implant migrating from its original longitudinal position or losing wall apposition in the face of continued aneurysmal dilatation. Migration, or the failure of longitudinal fixation, results in gradual loss of aortic approximation and the eventual repressurization of the aneurysm sac with its attendant risks of growth and rupture. The inability of stent- and barb-based endovascular fixation to resist aortic dilatation at the site of fixation also represents a late failure mode that can result in aneurysm rupture. A variety of endostaples or endoanchors designed to replicate the function of an interrupted aortic suture have been proposed and tested to varying degrees over the years. The device designed and produced by Aptus EndoSystems, now called the HeliFx Aortic EndoAnchor is the only independent endovascular fixation device that has achieved significant clinical usage and Food and Drug Administration approval. The experience with this device is now more than 5 years and it is approved for use in the broad market across both Europe and the United States. This article will review the engineering and design concepts underlying the HeliFx device as well as the in vitro and in vivo results using this device. Finally, a discussion of the potential for technical, procedural, and endograft innovation based on the availability of endovascular suturing will be reviewed. Copyright © 2012. Published by Elsevier Inc.

21 CFR 890.1850 - Diagnostic muscle stimulator.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1850 Diagnostic... electromyograph machine to initiate muscle activity. It is intended for medical purposes, such as to diagnose...

27 CFR 479.49 - Failure to register change or removal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Failure to register change or removal. 479.49 Section 479.49 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.48 - Failure to pay special (occupational) tax.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Failure to pay special (occupational) tax. 479.48 Section 479.48 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.48 - Failure to pay special (occupational) tax.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Failure to pay special (occupational) tax. 479.48 Section 479.48 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.49 - Failure to register change or removal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Failure to register change or removal. 479.49 Section 479.49 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.48 - Failure to pay special (occupational) tax.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Failure to pay special (occupational) tax. 479.48 Section 479.48 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.48 - Failure to pay special (occupational) tax.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Failure to pay special (occupational) tax. 479.48 Section 479.48 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.49 - Failure to register change or removal.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Failure to register change or removal. 479.49 Section 479.49 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.49 - Failure to register change or removal.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Failure to register change or removal. 479.49 Section 479.49 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.48 - Failure to pay special (occupational) tax.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Failure to pay special (occupational) tax. 479.48 Section 479.48 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

27 CFR 479.49 - Failure to register change or removal.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Failure to register change or removal. 479.49 Section 479.49 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES...

Techniques of Final Preseal Visual Inspection

NASA Technical Reports Server (NTRS)

Anstead, R. J.

1975-01-01

A dissertation is given on the final preseal visual inspection of microcircuit devices to detect manufacturing defects and reduce failure rates in service. The processes employed in fabricating monolithic integrated circuits and hybrid microcircuits, various failure mechanisms resulting from deficiencies in those processes, and the rudiments of performing final inspection are outlined.

Heart Failure

MedlinePlus

... cause heart failure, such as coronary artery disease, high blood pressure, diabetes or obesity. Symptoms Heart failure can be ongoing ( ... include: Not smoking Controlling certain conditions, such as high blood pressure and diabetes Staying physically active Eating healthy foods Maintaining a ...

Tribology symposium 1995. PD-Volume 72

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

Masudi, H.

After the keynote presentation by Professor Aaron Cohen of Texas A and M University, entitled Processes Used in Design, the program is divided into five major sessions: Research and Development -- Recent research and development of tribological components; Tribology in Manufacturing -- The impact of tribology on modern manufacturing; Design/Design Representation -- Aspects of design related to tribological systems; Tribo-Chemistry/Tribo-Physics -- Discussion of chemical and physical behavior of substances as related to tribology; and Failure Analysis -- An analysis of failure, failure detection, and failure monitoring as related to manufacturing processes. Papers have been processed separately for inclusion on themore » data base.« less

Dental transposition of canine and lateral incisor and impacted central incisor treatment: A case report

PubMed Central

Gebert, Tarcisio Jacinto; Palma, Vinícius Canavarros; Borges, Alvaro Henrique; Volpato, Luiz Evaristo Ricci

2014-01-01

Introduction Dental transposition and impaction are disorders related to ectopic eruption or failure in tooth eruption, which can affect child physical, mental and social development and may be difficult to be clinically solved. Methods We describe a case of transposition between the upper left canine and lateral incisor associated with impaction of the central incisor on the same side, in a 12-year-old patient. Conservative treatment involving surgical-orthodontic correction of transposed teeth and traction of the central incisor was conducted. Conclusion The option of correcting transposition and orthodontic traction by means of the segmented arch technique with devices such as cantilever and TMA rectangular wire loops, although a complex alternative, was proved to be esthetically and functionally effective. PMID:24713567

Development of chip passivated monolithic complementary MISFET circuits with beam leads

NASA Technical Reports Server (NTRS)

Ragonese, L. J.; Kim, M. J.; Corrie, B. L.; Brouillette, J. W.; Warr, R. E.

1972-01-01

The results are presented of a program to demonstrate the processes for fabricating complementary MISFET beam-leaded circuits, which, potentially, are comparable in quality to available bipolar beam-lead chips that use silicon nitride passivation in conjunction with a platinum-titanium-gold metal system. Materials and techniques, different from the bipolar case, were used in order to be more compatible with the special requirements of fully passivated complementary MISFET devices. Two types of circuits were designed and fabricated, a D-flip-flop and a three-input NOR/NAND gate. Fifty beam-leaded chips of each type were constructed. A quality and reliability assurance program was performed to identify failure mechanisms. Sample tests and inspections (including destructive) were developed to measure the physical characteristics of the circuits.

Reliability study of refractory gate gallium arsenide MESFETS

NASA Technical Reports Server (NTRS)

Yin, J. C. W.; Portnoy, W. M.

1981-01-01

Refractory gate MESFET's were fabricated as an alternative to aluminum gate devices, which have been found to be unreliable as RF power amplifiers. In order to determine the reliability of the new structures, statistics of failure and information about mechanisms of failure in refractory gate MESFET's are given. Test transistors were stressed under conditions of high temperature and forward gate current to enhance failure. Results of work at 150 C and 275 C are reported.

Reliability study of refractory gate gallium arsenide MESFETS

NASA Astrophysics Data System (ADS)

Yin, J. C. W.; Portnoy, W. M.

Refractory gate MESFET's were fabricated as an alternative to aluminum gate devices, which have been found to be unreliable as RF power amplifiers. In order to determine the reliability of the new structures, statistics of failure and information about mechanisms of failure in refractory gate MESFET's are given. Test transistors were stressed under conditions of high temperature and forward gate current to enhance failure. Results of work at 150 C and 275 C are reported.

Failure analysis on optical fiber on swarm flight payload

NASA Astrophysics Data System (ADS)

Bourcier, Frédéric; Fratter, Isabelle; Teyssandier, Florent; Barenes, Magali; Dhenin, Jérémie; Peyriguer, Marie; Petre-Bordenave, Romain

2017-11-01

Failure analysis on optical components is usually carried-out, on standard testing devices such as optical/electronic microscopes and spectrometers, on isolated but representative samples. Such analyses are not contactless and not totally non-invasive, so they cannot be used easily on flight models. Furthermore, for late payload or satellite integration/validation phases with tight schedule issues, it could be necessary to carry out a failure analysis directly on the flight hardware, in cleanroom.

21 CFR 890.3675 - Denis Brown splint.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3675 Denis Brown splint. (a... on young children with tibial torsion (excessive rotation of the lower leg) or club foot. (b...

Experimental Durability Testing of 4H SiC JFET Integrated Circuit Technology at 727 C

NASA Technical Reports Server (NTRS)

Spry, David; Neudeck, Phil; Chen, Liangyu; Chang, Carl; Lukco, Dorothy; Beheim, Glenn M

2016-01-01

We have reported SiC integrated circuits (IC's) with two levels of metal interconnect that have demonstrated prolonged operation for thousands of hours at their intended peak ambient operational temperature of 500 C [1, 2]. However, it is recognized that testing of semiconductor microelectronics at temperatures above their designed operating envelope is vital to qualification. Towards this end, we previously reported operation of a 4H-SiC JFET IC ring oscillator on an initial fast thermal ramp test through 727 C [3]. However, this thermal ramp was not ended until a peak temperature of 880 C (well beyond failure) was attained. Further experiments are necessary to better understand failure mechanisms and upper temperature limit of this extreme-temperature capable 4H-SiC IC technology. Here we report on additional experimental testing of custom-packaged 4H-SiC JFET IC devices at temperatures above 500 C. In one test, the temperature was ramped and then held at 727 C, and the devices were periodically measured until electrical failure was observed. A 4H-SiC JFET on this chip electrically functioned with little change for around 25 hours at 727 C before rapid increases in device resistance caused failure. In a second test, devices from our next generation 4H-SiC JFET ICs were ramped up and then held at 700 C (which is below the maximum deposition temperature of the dielectrics). Three ring oscillators functioned for 8 hours at this temperature before degradation. In a third experiment, an alternative die attach of gold paste and package lid was used, and logic circuit operation was demonstrated for 143.5 hours at 700 C.

Experimental Durability Testing of 4H SiC JFET Integrated Circuit Technology at 727 Degrees Centigrade

NASA Technical Reports Server (NTRS)

Spry, David J.; Neudeck, Philip G.; Chen, Liangyu; Chang, Carl W.; Lukco, Dorothy; Beheim, Glenn M.

2016-01-01

We have reported SiC integrated circuits (ICs) with two levels of metal interconnect that have demonstrated prolonged operation for thousands of hours at their intended peak ambient operational temperature of 500 degrees Centigrade. However, it is recognized that testing of semiconductor microelectronics at temperatures above their designed operating envelope is vital to qualification. Towards this end, we previously reported operation of a 4H-SiC JFET IC ring oscillator on an initial fast thermal ramp test through 727 degrees Centigrade. However, this thermal ramp was not ended until a peak temperature of 880 degrees Centigrade (well beyond failure) was attained. Further experiments are necessary to better understand failure mechanisms and upper temperature limit of this extreme-temperature capable 4H-SiC IC technology.Here we report on additional experimental testing of custom-packaged 4H-SiC JFET IC devices at temperatures above 500 degrees Centigrade. In one test, the temperature was ramped and then held at 727 degrees Centigrade, and the devices were periodically measured until electrical failure was observed. A 4H-SiC JFET on this chip electrically functioned with little change for around 25 hours at 727 degrees Centigrade before rapid increases in device resistance caused failure. In a second test, devices from our next generation 4H-SiC JFET ICs were ramped up and then held at 700 degrees Centigrade (which is below the maximum deposition temperature of the dielectrics). Three ring oscillators functioned for 8 hours at this temperature before degradation. In a third experiment, an alternative die attach of gold paste and package lid was used, and logic circuit operation was demonstrated for 143.5 hours at 700 degrees Centigrade.

Utility of the Seattle Heart Failure Model in patients with advanced heart failure.

PubMed

Kalogeropoulos, Andreas P; Georgiopoulou, Vasiliki V; Giamouzis, Grigorios; Smith, Andrew L; Agha, Syed A; Waheed, Sana; Laskar, Sonjoy; Puskas, John; Dunbar, Sandra; Vega, David; Levy, Wayne C; Butler, Javed

2009-01-27

The aim of this study was to validate the Seattle Heart Failure Model (SHFM) in patients with advanced heart failure (HF). The SHFM was developed primarily from clinical trial databases and extrapolated the benefit of interventions from published data. We evaluated the discrimination and calibration of SHFM in 445 advanced HF patients (age 52 +/- 12 years, 68.5% male, 52.4% white, ejection fraction 18 +/- 8%) referred for cardiac transplantation. The primary end point was death (n = 92), urgent transplantation (n = 14), or left ventricular assist device (LVAD) implantation (n = 3); a secondary analysis was performed on mortality alone. Patients were receiving optimal therapy (angiotensin-II modulation 92.8%, beta-blockers 91.5%, aldosterone antagonists 46.3%), and 71.0% had an implantable device (defibrillator 30.4%, biventricular pacemaker 3.4%, combined 37.3%). During a median follow-up of 21 months, 109 patients (24.5%) had an event. Although discrimination was adequate (c-statistic >0.7), the SHFM overall underestimated absolute risk (observed vs. predicted event rate: 11.0% vs. 9.2%, 21.0% vs. 16.6%, and 27.9% vs. 22.8% at 1, 2, and 3 years, respectively). Risk underprediction was more prominent in patients with an implantable device. The SHFM had different calibration properties in white versus black patients, leading to net underestimation of absolute risk in blacks. Race-specific recalibration improved the accuracy of predictions. When analysis was restricted to mortality, the SHFM exhibited better performance. In patients with advanced HF, the SHFM offers adequate discrimination, but absolute risk is underestimated, especially in blacks and in patients with devices. This is more prominent when including transplantation and LVAD implantation as an end point.

Lifetime assessment of atomic-layer-deposited Al2O3-Parylene C bilayer coating for neural interfaces using accelerated age testing and electrochemical characterization.

PubMed

Minnikanti, Saugandhika; Diao, Guoqing; Pancrazio, Joseph J; Xie, Xianzong; Rieth, Loren; Solzbacher, Florian; Peixoto, Nathalia

2014-02-01

The lifetime and stability of insulation are critical features for the reliable operation of an implantable neural interface device. A critical factor for an implanted insulation's performance is its barrier properties that limit access of biological fluids to the underlying device or metal electrode. Parylene C is a material that has been used in FDA-approved implantable devices. Considered a biocompatible polymer with barrier properties, it has been used as a substrate, insulation or an encapsulation for neural implant technology. Recently, it has been suggested that a bilayer coating of Parylene C on top of atomic-layer-deposited Al2O3 would provide enhanced barrier properties. Here we report a comprehensive study to examine the mean time to failure of Parylene C and Al2O3-Parylene C coated devices using accelerated lifetime testing. Samples were tested at 60°C for up to 3 months while performing electrochemical measurements to characterize the integrity of the insulation. The mean time to failure for Al2O3-Parylene C was 4.6 times longer than Parylene C coated samples. In addition, based on modeling of the data using electrical circuit equivalents, we show here that there are two main modes of failure. Our results suggest that failure of the insulating layer is due to pore formation or blistering as well as thinning of the coating over time. The enhanced barrier properties of the bilayer Al2O3-Parylene C over Parylene C makes it a promising candidate as an encapsulating neural interface. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Efficacy of Blunt Force Trauma, a Novel Mechanical Cervical Dislocation Device, and a Non-Penetrating Captive Bolt Device for On-Farm Euthanasia of Pre-Weaned Kits, Growers, and Adult Commercial Meat Rabbits.

PubMed

Walsh, Jessica L; Percival, Aaron; Turner, Patricia V

2017-12-15

The commercial meat rabbit industry is without validated on-farm euthanasia methods, potentially resulting in inadequate euthanasia protocols. We evaluated blunt force trauma (BFT), a mechanical cervical dislocation device (MCD), and a non-penetrating captive bolt device (NPCB) for euthanasia of pre-weaned kits, growers, and adult rabbits. Trials were conducted on three commercial meat rabbit farms using 170 cull rabbits. Insensibility was assessed by evaluating absence of brainstem and spinal reflexes, rhythmic breathing, and vocalizations. Survey radiographs on a subsample of rabbits ( n = 12) confirmed tissue damage prior to gross dissection and microscopic evaluation. All 63 rabbits euthanized by the NPCB device were rendered immediately and irreversibly insensible. The MCD device was effective in 46 of 49 (94%) rabbits. Method failure was highest for BFT with euthanasia failures in 13 of 58 (22%) rabbits. Microscopically, brain sections from rabbits killed with the NPCB device had significantly more damage than those from rabbits killed with BFT ( p = 0.001). We conclude that BFT is neither consistently humane nor effective as a euthanasia method. MCD is an accurate and reliable euthanasia method generally causing clean dislocation and immediate and irreversible insensibility, and the NPCB device was 100% effective and reliable in rabbits >150 g.

SPILL ALERT DEVICE FOR EARTH DAM FAILURE WARNING

EPA Science Inventory

A spill alert device for determining earth dam safety based on the monitoring of the acoustic emissions generated in a deforming soil mass was developed and field-tested. The acoustic emissions are related to the basic mechanisms from which soils derive their strength. Laboratory...

21 CFR 870.5225 - External counter-pulsating device.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., prescription device used to assist the heart by applying positive or negative pressure to one or more of the body's limbs in synchrony with the heart cycle. (b) Classification. (1) Class II (special controls... angina pectoris; acute myocardial infarction; cardiogenic shock; congestive heart failure; postoperative...

Triggering Mechanism for Neutron Induced Single-Event Burnout in Power Devices

NASA Astrophysics Data System (ADS)

Shoji, Tomoyuki; Nishida, Shuichi; Hamada, Kimimori

2013-04-01

Cosmic ray neutrons can trigger catastrophic failures in power devices. It has been reported that parasitic transistor action causes single-event burnout (SEB) in power metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs). However, power diodes do not have an inherent parasitic transistor. In this paper, we describe the mechanism triggering SEB in power diodes for the first time using transient device simulation. Initially, generated electron-hole pairs created by incident recoil ions generate transient current, which increases the electron density in the vicinity of the n-/n+ boundary. The space charge effect of the carriers leads to an increase in the strength of the electric field at the n-/n+ boundary. Finally, the onset of impact ionization at the n-/n+ boundary can trigger SEB. Furthermore, this failure is closely related to diode secondary breakdown. It was clarified that the impact ionization at the n-/n+ boundary is a key point of the mechanism triggering SEB in power devices.

The quantum pinch effect in semiconducting quantum wires: A bird’s-eye view

NASA Astrophysics Data System (ADS)

Kushwaha, Manvir S.

2016-01-01

Those who measure success with culmination do not seem to be aware that life is a journey not a destination. This spirit is best reflected in the unceasing failures in efforts for solving the problem of controlled thermonuclear fusion for even the simplest pinches for over decades; and the nature keeps us challenging with examples. However, these efforts have permitted researchers the obtention of a dense plasma with a lifetime that, albeit short, is sufficient to study the physics of the pinch effect, to create methods of plasma diagnostics, and to develop a modern theory of plasma processes. Most importantly, they have impregnated the solid state plasmas, particularly the electron-hole plasmas in semiconductors, which do not suffer from the issues related with the confinement and which have demonstrated their potential not only for the fundamental physics but also for the device physics. Here, we report on a two-component, cylindrical, quasi-one-dimensional quantum plasma subjected to a radial confining harmonic potential and an applied magnetic field in the symmetric gauge. It is demonstrated that such a system, as can be realized in semiconducting quantum wires, offers an excellent medium for observing the quantum pinch effect at low temperatures. An exact analytical solution of the problem allows us to make significant observations: Surprisingly, in contrast to the classical pinch effect, the particle density as well as the current density display a determinable maximum before attaining a minimum at the surface of the quantum wire. The effect will persist as long as the equilibrium pair density is sustained. Therefore, the technological promise that emerges is the route to the precise electronic devices that will control the particle beams at the nanoscale.

Security Analysis of Smart Grid Cyber Physical Infrastructures Using Modeling and Game Theoretic Simulation

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

Abercrombie, Robert K; Sheldon, Frederick T.

Cyber physical computing infrastructures typically consist of a number of sites are interconnected. Its operation critically depends both on cyber components and physical components. Both types of components are subject to attacks of different kinds and frequencies, which must be accounted for the initial provisioning and subsequent operation of the infrastructure via information security analysis. Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, andmore » information assets. We concentrated our analysis on the electric sector failure scenarios and impact analyses by the NESCOR Working Group Study, From the Section 5 electric sector representative failure scenarios; we extracted the four generic failure scenarios and grouped them into three specific threat categories (confidentiality, integrity, and availability) to the system. These specific failure scenarios serve as a demonstration of our simulation. The analysis using our ABGT simulation demonstrates how to model the electric sector functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the cyber physical infrastructure network with respect to CIA.« less

Management protocols for chronic heart failure in India.

PubMed

Mishra, S; Mohan, J C; Nair, Tiny; Chopra, V K; Harikrishnan, S; Guha, S; Ramakrishnan, S; Ray, S; Sethi, R; Samal, U C; Sarat Chandra, K; Hiremath, M S; Banerjee, A K; Kumar, S; Das, M K; Deb, P K; Bahl, V K

Heart failure is a common clinical syndrome and a global health priority. The burden of heart failure is increasing at an alarming rate worldwide as well as in India. Heart failure not only increases the risk of mortality, morbidity and worsens the patient's quality of life, but also puts a huge burden on the overall healthcare system. The management of heart failure has evolved over the years with the advent of new drugs and devices. This document has been developed with an objective to provide standard management guidance and simple heart failure algorithms to aid Indian clinicians in their daily practice. It would also inform the clinicians on the latest evidence in heart failure and provide guidance to recognize and diagnose chronic heart failure early and optimize management. Copyright © 2017. Published by Elsevier B.V.

Rehabilitation Therapy in Older Acute Heart Failure Patients (REHAB-HF) Trial: Design and Rationale

PubMed Central

Reeves, Gordon R.; Whellan, David J.; Duncan, Pamela; O’Connor, Christopher M.; Pastva, Amy M.; Eggebeen, Joel D; Hewston, Leigh Ann; Morgan, Timothy M.; Reed, Shelby D.; Rejeski, W. Jack; Mentz, Robert J.; Rosenberg, Paul B.; Kitzman, Dalane W.

2017-01-01

Background Acute decompensated heart failure (ADHF) is a leading cause of hospitalization in older persons in the United States. Reduced physical function and frailty are major determinants of adverse outcomes in older patients with hospitalized ADHF. However, these are not addressed by current heart failure (HF) management strategies and there has been little study of exercise training in older, frail HF patients with recent ADHF. Hypothesis Targeting physical frailty with a multi-domain structured physical rehabilitation intervention will improve physical function and reduce adverse outcomes among older patients experiencing a HF hospitalization. Study Design Rehabilitation Therapy in Older Acute Heart Failure Patients (REHAB-HF) is a multi-center clinical trial in which 360 patients ≥ 60 years hospitalized with ADHF will be randomized either to a novel 12-week multi-domain physical rehabilitation intervention or to attention control. The goal of the intervention is to improve balance, mobility, strength and endurance utilizing reproducible, targeted exercises administered by a multi-disciplinary team with specific milestones for progression. The primary study aim is to assess the efficacy of the REHAB-HF intervention on physical function measured by total Short Physical Performance Battery score. The secondary outcome is 6-month all-cause rehospitalization. Additional outcome measures include quality of life and costs. Conclusions REHAB-HF is the first randomized trial of a physical function intervention in older patients with hospitalized ADHF designed to determine if addressing deficits in balance, mobility, strength and endurance improves physical function and reduces rehospitalizations. It will address key evidence gaps concerning the role of physical rehabilitation in the care of older patients, those with ADHF, frailty, and multiple comorbidities. PMID:28267466

The calibration of photographic and spectroscopic films. 1: Film batch variations of reciprocity failure in IIaO film. 2: Thermal and aging effects in relationship to reciprocity failure. 3: Shifting of reciprocity failure points as a function of thermal and aging effects

NASA Technical Reports Server (NTRS)

Peters, K. A.; Atkinson, P. F.; Hammond, E. C., Jr.

1986-01-01

Reciprocity failure was examined for IIaO spectroscopic film. Three separate experiments were performed in order to study film batch variations, thermal and aging effects in relationship to reciprocity failure, and shifting of reciprocity failure points as a function of thermal and aging effects. The failure was examined over ranges of time between 5 and 60 seconds. The variation to illuminance was obtained by using thirty neutral density filters. A standard sensitometer device imprinted the wedge pattern on the film as exposure time was subjected to variation. The results indicate that film batch differences, temperature, and aging play an important role in reciprocity failure of IIaO spectroscopic film. A shifting of the failure points was also observed in various batches of film.

Is perceived failure in school performance a trigger of physical injury? A case-crossover study of children in Stockholm County

PubMed Central

Laflamme, L; Engstrom, K; Moller, J; Hallqvist, J

2004-01-01

Objectives: To investigate whether perceived failure in school performance increases the potential for children to be physically injured. Subjects: Children aged 10–15 years residing in the Stockholm County and hospitalised or called back for a medical check up because of a physical injury during the school years 2000–2001 and 2001–2002 (n = 592). Methods: A case-crossover design was used and information on potential injury triggers was gathered by interview. Information about family socioeconomic circumstances was gathered by a questionnaire filled in by parents during the child interview (response rate 87%). Results: Perceived failure in school performance has the potential to trigger injury within up to 10 hours subsequent to exposure (relative risk = 2.70; 95% confidence intervals = 1.2 to 5.8). The risk is significantly higher among pre-adolescents and among children from families at a higher education level. Conclusions: Experiencing feelings of failure may affect children's physical safety, in particular among pre-adolescents. Possible mechanisms are perceptual deficits and response changes occasioned by the stress experienced after exposure. PMID:15082740

Bioartificial liver: current status.

PubMed

Pless, G; Sauer, I M

2005-11-01

Liver failure remains a life-threatening syndrome. With the growing disparity between the number of suitable donor organs and the number of patients awaiting transplantation, efforts have been made to optimize the allocation of organs, to find alternatives to cadaveric liver transplantation, and to develop extracorporeal methods to support or replace the function of the failing organ. An extracorporeal liver support system has to provide the main functions of the liver: detoxification, synthesis, and regulation. The understanding that the critical issue of the clinical syndrome in liver failure is the accumulation of toxins not cleared by the failing liver led to the development of artificial filtration and adsorption devices (artificial liver support). Based on this hypothesis, the removal of lipophilic, albumin-bound substances, such as bilirubin, bile acids, metabolites of aromatic amino acids, medium-chain fatty acids, and cytokines, should be beneficial to the clinical course of a patient in liver failure. Artificial detoxification devices currently under clinical evaluation include the Molecular Adsorbent Recirculating System (MARS), Single-Pass Albumin Dialysis (SPAD), and the Prometheus system. The complex tasks of regulation and synthesis remain to be addressed by the use of liver cells (bioartificial liver support). The Extracorporeal Liver Assist Device (ELAD), HepatAssist, Modular Extracorporeal Liver Support system (MELS), and the Amsterdam Medical Center Bioartificial Liver (AMC-BAL) are bioartificial systems. This article gives a brief overview on these artificial and bioartificial devices and discusses remaining obstacles.

Stretchable and foldable electronic devices

DOEpatents

Rogers, John A; Huang, Yonggang; Ko, Heung Cho; Stoykovich, Mark; Choi, Won Mook; Song, Jizhou; Ahn, Jong Hyun; Kim, Dae Hyeong

2013-10-08

Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.

Stretchable and foldable electronic devices

DOEpatents

Rogers, John A; Huang, Yonggang; Ko, Heung Cho; Stoykovich, Mark; Choi, Won Mook; Song, Jizhou; Ahn, Jong Hyun; Kim, Dae Hyeong

2014-12-09

Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.

Triplexer Monitor Design for Failure Detection in FTTH System

NASA Astrophysics Data System (ADS)

Fu, Minglei; Le, Zichun; Hu, Jinhua; Fei, Xia

2012-09-01

Triplexer was one of the key components in FTTH systems, which employed an analog overlay channel for video broadcasting in addition to bidirectional digital transmission. To enhance the survivability of triplexer as well as the robustness of FTTH system, a multi-ports device named triplexer monitor was designed and realized, by which failures at triplexer ports can be detected and localized. Triplexer monitor was composed of integrated circuits and its four input ports were connected with the beam splitter whose power division ratio was 95∶5. By means of detecting the sampled optical signal from the beam splitters, triplexer monitor tracked the status of the four ports in triplexer (e.g. 1310 nm, 1490 nm, 1550 nm and com ports). In this paper, the operation scenario of the triplexer monitor with external optical devices was addressed. And the integrated circuit structure of the triplexer monitor was also given. Furthermore, a failure localization algorithm was proposed, which based on the state transition diagram. In order to measure the failure detection and localization time under the circumstance of different failed ports, an experimental test-bed was built. Experiment results showed that the detection time for the failure at 1310 nm port by the triplexer monitor was less than 8.20 ms. For the failure at 1490 nm or 1550 nm port it was less than 8.20 ms and for the failure at com port it was less than 7.20 ms.

Quality of Life for Saudi Patients With Heart Failure: A Cross-Sectional Correlational Study

PubMed Central

AbuRuz, Mohannad Eid; Alaloul, Fawwaz; Saifan, Ahmed; Masa’Deh, Rami; Abusalem, Said

2016-01-01

Introduction: Heart failure is a major public health issue and a growing concern in developing countries, including Saudi Arabia. Most related research was conducted in Western cultures and may have limited applicability for individuals in Saudi Arabia. Thus, this study assesses the quality of life of Saudi patients with heart failure. Materials and Methods: A cross-sectional correlational design was used on a convenient sample of 103 patients with heart failure. Data were collected using the Short Form-36 and the Medical Outcomes Study-Social Support Survey. Results: Overall, the patients’ scores were low for all domains of Quality of Life. The Physical Component Summary and Mental Component Summary mean scores and SDs were (36.7±12.4, 48.8±6.5) respectively, indicating poor Quality of Life. Left ventricular ejection fraction was the strongest predictor of both physical and mental summaries. Conclusion: Identifying factors that impact quality of life for Saudi heart failure patients is important in identifying and meeting their physical and psychosocial needs. PMID:26493415

Prognostic value of the physical examination in patients with heart failure and atrial fibrillation: insights from the AF-CHF trial (atrial fibrillation and chronic heart failure).

PubMed

Caldentey, Guillem; Khairy, Paul; Roy, Denis; Leduc, Hugues; Talajic, Mario; Racine, Normand; White, Michel; O'Meara, Eileen; Guertin, Marie-Claude; Rouleau, Jean L; Ducharme, Anique

2014-02-01

This study sought to assess the prognostic value of physical examination in a modern treated heart failure population. The physical examination is the cornerstone of the evaluation and monitoring of patients with heart failure. Yet, the prognostic value of congestive signs (i.e., peripheral edema, jugular venous distension, a third heart sound, and pulmonary rales) has not been assessed in the current era. A post-hoc analysis was conducted on all 1,376 patients, 81% male, mean age 67 ± 11 years, with symptomatic left ventricular systolic dysfunction enrolled in the AF-CHF (Atrial Fibrillation and Congestive Heart Failure) trial. The prognostic value of baseline physical examination findings was assessed in univariate and multivariate Cox regression analyses. Peripheral edema was observed in 425 (30.9%), jugular venous distension in 297 (21.6%), a third heart sound in 207 (15.0%), and pulmonary rales in 178 (12.9%) patients. Death from cardiovascular causes occurred in 357 (25.9%) patients over a mean follow-up of 37 ± 19 months. All 4 physical examination findings were associated with cardiovascular mortality in univariate analyses (all p values <0.01). In multivariate analyses, taking all 4 signs as potential covariates, only rales (hazard ratio 1.41; 95% confidence interval: 1.07 to 1.86; p = 0.013) and peripheral edema (hazard ratio: 1.25; 95% confidence interval: 1.00 to 1.57; p = 0.048) were associated with cardiovascular mortality, independent of other variables. In the modern era, congestive signs on the physical examination (i.e., peripheral edema, jugular venous distension, a third heart sound, and pulmonary rales) continue to provide important prognostic information in patients with congestive heart failure. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

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

Peters, K.A.; Atkinson, P.F.; Hammond, E.C.,JR.

Reciprocity failure was examined for IIaO spectroscopic film. Three separate experiments were performed in order to study film batch variations, thermal and aging effects in relationship to reciprocity failure, and shifting of reciprocity failure points as a function of thermal and aging effects. The failure was examined over ranges of time between 5 and 60 seconds. The variation to illuminance was obtained by using thirty neutral density filters. A standard sensitometer device imprinted the wedge pattern on the film as exposure time was subjected to variation. The results indicate that film batch differences, temperature, and aging play an important rolemore » in reciprocity failure of IIaO spectroscopic film. A shifting of the failure points was also observed in various batches of film.« less

8 CFR 214.4 - Denial of certification, denial of recertification or withdrawal of SEVP certification.

Code of Federal Regulations, 2011 CFR

2011-01-01

...). (xii) Failure to operate as a bona fide institution of learning. (xiii) Failure to employ adequate...) Failure to maintain the physical plant, curriculum, and teaching staff in the manner represented in the...

Overview of implantable cardioverter defibrillator and cardiac resynchronisation therapy in heart failure management

PubMed Central

Chia, Pow-Li; Foo, David

2016-01-01

Clinical trials have established the benefits of implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) in the treatment of heart failure patients. As adjuncts to guideline-directed medical therapy, ICDs confer mortality benefits from sudden cardiac arrest, while CRT reduces mortality, hospitalisation rates and improves functional capacity. This review discusses the use of ICDs and CRT devices in heart failure management, outlining the evidence supporting their use, indications and contraindications. PMID:27440409

Generalized Phenomenological Cyclic Stress-Strain-Strength Characterization of Granular Media.

DTIC Science & Technology

1984-09-02

could be fitted to a comprehensive data set. i ’../., Unfortunately, such equipment is not available at present, and most researchers still rely on the...notably, Lade and Duncan (1975), using a comprehensive series of test data obtained from a true triaxial device (Lade, 1973), have suggested that failure...0 VV 2. Shear Strain, low indeterminate (prior to failure) (at failure) 3. Deformation small large 4. Void Ratio (e) any e ecritical 5. Grain

Microcircuit Device Reliability. Digital Failure Rate Data

DTIC Science & Technology

1981-01-01

Center Staff I IT Research Institute Under Contract to: Rome Air Development Center Griffiss AFB, NY 13441 fortes Ordering No. MDR- 17 biKi frbi...r ■■ ■—■ — SECURITY CLASSIFICATION Or THIS PAGE (Whin Dmlm Enlti»<l) REPORT DOCUMENTATION PAGE «EPO«TNUMBER MDR- 17 4. TITLE (md...MDR- 17 presents com- parisons between actual field experienced failure rates and MIL-HDBK-217C, Notice 1, predicted failure rates. The use of

Lessons learned from 150 continuous-flow left ventricular assist devices: a single institutional 7 year experience.

PubMed

Tsiouris, Athanasios; Paone, Gaetano; Nemeh, Hassan W; Brewer, Robert J; Borgi, Jamil; Hodari, Arielle; Morgan, Jeffrey A

2015-01-01

Continuous-flow (CF) left ventricular assist devices (LVADs) have become the standard of care for patients with advanced heart failure refractory to optimal medical therapy. The goal of this study was to review our 7 year single institutional experience with CF LVADs. Mean age was 50.4 + 12.5 (17-69) years for bridge-to-transplantation (BTT) patients and 57.6 + 10.4 (31-81) years for destination therapy (DT) patients (p < 0.001). Overall, 38 patients (26%) were female and 58 (41%) were African American. Etiology of heart failure was ischemic in 54 patients (37%) and nonischemic in 93 patients (63%). Overall survival at 30 days, 6 months, 12 months, and 2 years was 93%, 89%, 84%, and 81%, respectively. Gastrointestinal bleeding (GIB) was the most common complication (24%), followed by stroke (18%), right ventricular (RV) failure (18%), ventilator-dependent respiratory failure (10%), reoperation for bleeding (10%), and driveline infection (9%). These data demonstrate excellent survival with low mortality for both BTT and DT patients on long-term LVAD support. However, for LVAD therapy to become the gold standard for long-term treatment of end-stage heart failure and a plausible alternative to heart transplantation, we need to continue to improve the incidence of frequent postoperative complications, such as RV failure, driveline infections, strokes, and GIB.

Comparison of a novel fixation device with standard suturing methods for spinal cord stimulators.

PubMed

Bowman, Richard G; Caraway, David; Bentley, Ishmael

2013-01-01

Spinal cord stimulation is a well-established treatment for chronic neuropathic pain of the trunk or limbs. Currently, the standard method of fixation is to affix the leads of the neuromodulation device to soft tissue, fascia or ligament, through the use of manually tying general suture. A novel semiautomated device is proposed that may be advantageous to the current standard. Comparison testing in an excised caprine spine and simulated bench top model was performed. Three tests were performed: 1) perpendicular pull from fascia of caprine spine; 2) axial pull from fascia of caprine spine; and 3) axial pull from Mylar film. Six samples of each configuration were tested for each scenario. Standard 2-0 Ethibond was compared with a novel semiautomated device (Anulex fiXate). Upon completion of testing statistical analysis was performed for each scenario. For perpendicular pull in the caprine spine, the failure load for standard suture was 8.95 lbs with a standard deviation of 1.39 whereas for fiXate the load was 15.93 lbs with a standard deviation of 2.09. For axial pull in the caprine spine, the failure load for standard suture was 6.79 lbs with a standard deviation of 1.55 whereas for fiXate the load was 12.31 lbs with a standard deviation of 4.26. For axial pull in Mylar film, the failure load for standard suture was 10.87 lbs with a standard deviation of 1.56 whereas for fiXate the load was 19.54 lbs with a standard deviation of 2.24. These data suggest a novel semiautomated device offers a method of fixation that may be utilized in lieu of standard suturing methods as a means of securing neuromodulation devices. Data suggest the novel semiautomated device in fact may provide a more secure fixation than standard suturing methods. © 2012 International Neuromodulation Society.

Investigation of short-circuit failure mechanisms of SiC MOSFETs by varying DC bus voltage

NASA Astrophysics Data System (ADS)

Namai, Masaki; An, Junjie; Yano, Hiroshi; Iwamuro, Noriyuki

2018-07-01

In this study, the experimental evaluation and numerical analysis of short-circuit mechanisms of 1200 V SiC planar and trench MOSFETs were conducted at various DC bus voltages from 400 to 800 V. Investigation of the impact of DC bus voltage on short-circuit capability yielded results that are extremely useful for many existing power electronics applications. Three failure mechanisms were identified in this study: thermal runaway, MOS channel current following device turn-off, and rupture of the gate oxide layer (gate oxide layer damage). The SiC MOSFETs experienced lattice temperatures exceeding 1000 K during the short-circuit transient; as Si insulated gate bipolar transistors (IGBTs) are not typically subject to such temperatures, the MOSFETs experienced distinct failure modes, and the mode experienced was significantly influenced by the DC bus voltage. In conclusion, suggestions regarding the SiC MOSFET design and operation methods that would enhance device robustness are proposed.

Recommendations for pacemaker implantation for the treatment of atrial tachyarrhythmias and resynchronisation therapy for heart failure: A report from the task force on pacemaker indications of the Dutch Working Group on Cardiac Pacing.

PubMed

van Hemel, N M; Dijkman, B; de Voogt, W G; Beukema, W P; Bosker, H A; de Cock, C C; Jordaens, L J L M; van Gelder, I C; van Gelder, L M; van Mechelen, R; Ruiter, J H; Sedney, M I; Slegers, L C

2004-01-01

Today, new pacing algorithms and stimulation methods for the prevention and interruption of atrial tachyarrhythmias can be applied on patients who need bradycardia pacing for conventional reasons. In addition, biventricular pacing as additive treatment for patients with severe congestive heart failure due to ventricular systolic dysfunction and prolonged intraventricular conduction has shown to improve symptoms and reduce hospital admissions. These new pacing technologies and the optimising of the pacing programmes are complex, expensive and time-consuming. Based on many clinical studies the indications for these devices are beginning to emerge. To support the cardiologist's decision-making and to prevent waste of effort and resources, the 'ad hoc committee' has provided preliminary recommendations for implantable devices to treat atrial tachyarrhythmias and to extend the treatment of congestive heart failure respectively.

Automated Bone Screw Tightening to Adaptive Levels of Stripping Torque.

PubMed

Reynolds, Karen J; Mohtar, Aaron A; Cleek, Tammy M; Ryan, Melissa K; Hearn, Trevor C

2017-06-01

To use relationships between tightening parameters, related to bone quality, to develop an automated system that determines and controls the level of screw tightening. An algorithm relating current at head contact (IHC) to current at construct failure (Imax) was developed. The algorithm was used to trigger cessation of screw insertion at a predefined tightening level, in real time, between head contact and maximum current. The ability of the device to stop at the predefined level was assessed. The mean (±SD) current at which screw insertion ceased was calculated to be [51.47 ± 9.75% × (Imax - IHC)] + IHC, with no premature bone failures. A smart screwdriver was developed that uses the current from the motor driving the screw to predict the current at which the screw will strip the bone threads. The device was implemented and was able to achieve motor shut-off and cease tightening at a predefined threshold, with no premature bone failures.

Canary in the coal mine-Initial reports of thermal injury secondary to electronic cigarettes.

PubMed

Bauman, Zachary M; Roman, Jordan; Singer, Matthew; Vercruysse, Gary A

2017-05-01

The use of electronic cigarettes has become increasingly popular with claims suggesting healthier alternatives to tobacco cigarettes. However, research regarding the safety of such devices has been limited to an analysis of the inhaled vapor and the short and long-term effects on the body. A lesser recognized risk of electronic cigarette use is that of lithium-ion battery failure causing ignition, leading to severe thermal injury. Such incidents have been reported in the media but with inconsistencies from a lack of focus on the injuries sustained and a cause of ignition. The cases presented here are among the first recognized thermal injuries sustained from electronic cigarette lithium-ion battery failure, the potential rationale for these failures, and a need for increased awareness of the safety hazards of these devices. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

46 CFR 161.002-8 - Automatic fire detecting systems, general requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... detecting system shall consist of a power supply; a control unit on which are located visible and audible... control unit. Power failure alarm devices may be separately housed from the control unit and may be combined with other power failure alarm systems when specifically approved. (b) [Reserved] [21 FR 9032, Nov...

46 CFR 161.002-8 - Automatic fire detecting systems, general requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... detecting system shall consist of a power supply; a control unit on which are located visible and audible... control unit. Power failure alarm devices may be separately housed from the control unit and may be combined with other power failure alarm systems when specifically approved. (b) [Reserved] [21 FR 9032, Nov...

Chronic Heart Failure: Contemporary Diagnosis and Management

PubMed Central

Ramani, Gautam V.; Uber, Patricia A.; Mehra, Mandeep R.

2010-01-01

Chronic heart failure (CHF) remains the only cardiovascular disease with an increasing hospitalization burden and an ongoing drain on health care expenditures. The prevalence of CHF increases with advancing life span, with diastolic heart failure predominating in the elderly population. Primary prevention of coronary artery disease and risk factor management via aggressive blood pressure control are central in preventing new occurrences of left ventricular dysfunction. Optimal therapy for CHF involves identification and correction of potentially reversible precipitants, target-dose titration of medical therapy, and management of hospitalizations for decompensation. The etiological phenotype, absolute decrease in left ventricular ejection fraction and a widening of QRS duration on electrocardiography, is commonly used to identify patients at increased risk of progression of heart failure and sudden death who may benefit from prophylactic implantable cardioverter-defibrillator placement with or without cardiac resynchronization therapy. Patients who transition to advanced stages of disease despite optimal traditional medical and device therapy may be candidates for hemodynamically directed approaches such as a left ventricular assist device; in selected cases, listing for cardiac transplant may be warranted. PMID:20118395

The total artificial heart

PubMed Central

Cook, Jason A.; Shah, Keyur B.; Quader, Mohammed A.; Cooke, Richard H.; Kasirajan, Vigneshwar; Rao, Kris K.; Smallfield, Melissa C.; Tchoukina, Inna

2015-01-01

The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient’s native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review. PMID:26793338

FDIR Strategy Validation with the B Method

NASA Astrophysics Data System (ADS)

Sabatier, D.; Dellandrea, B.; Chemouil, D.

2008-08-01

In a formation flying satellite system, the FDIR strategy (Failure Detection, Isolation and Recovery) is paramount. When a failure occurs, satellites should be able to take appropriate reconfiguration actions to obtain the best possible results given the failure, ranging from avoiding satellite-to-satellite collision to continuing the mission without disturbance if possible. To achieve this goal, each satellite in the formation has an implemented FDIR strategy that governs how it detects failures (from tests or by deduction) and how it reacts (reconfiguration using redundant equipments, avoidance manoeuvres, etc.). The goal is to protect the satellites first and the mission as much as possible. In a project initiated by the CNES, ClearSy experiments the B Method to validate the FDIR strategies developed by Thales Alenia Space, of the inter satellite positioning and communication devices that will be used for the SIMBOL-X (2 satellite configuration) and the PEGASE (3 satellite configuration) missions and potentially for other missions afterward. These radio frequency metrology sensor devices provide satellite positioning and inter satellite communication in formation flying. This article presents the results of this experience.

Failure of a vagus nerve stimulator following a nearby lightning strike.

PubMed

Terry, Garth E; Conry, Joan A; Taranto, Eleanor; Yaun, Amanda

2011-01-01

We recently reported our experience with implanted vagus nerve stimulators (VNS) in 62 children over a 7-year period. Here, we present a case of a VNS that successfully reduced the number and severity of seizures in a patient with an unusual seizure pattern, and failed to function shortly after a lightning storm. To our knowledge, the failure of VNS or any implantable electrical devices by lightning has not been reported in the literature. This mechanism of electrical interference, while unusual, may require more attention as these devices are expected to be used more frequently. Copyright © 2011 S. Karger AG, Basel.

Depression, psychological distress, and quality of life in patients with cardioverter defibrillator with or without cardiac resynchronization therapy.

PubMed

Knackstedt, Christian; Arndt, Marlies; Mischke, Karl; Marx, Nikolaus; Nieman, Fred; Kunert, Hanns Jürgen; Schauerte, Patrick; Norra, Christine

2014-05-01

Congestive heart failure is frequent and leads to reduced exercise capacity, reduced quality of life (QoL), and depression in many patients. Cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillators (ICD) offer therapeutic options and may have an impact on QoL and depression. This study was performed to evaluate physical and mental health in patients undergoing ICD or combined CRT/ICD-implantation (CRT-D). Echocardiography, spiroergometry, and psychometric questionnaires [Beck Depression Inventory, General World Health Organization Five Well-being Index (WHO-5), Brief Symptom Inventory and 36-item Short Form (SF-36)] were obtained in 39 patients (ICD: 17, CRT-D: 22) at baseline and 6-month follow-up (FU) after device implantation. CRT-D patients had a higher NYHA class and broader left bundle branch block than ICD patients at baseline. At FU, ejection fraction (EF), peak oxygen uptake, and NYHA class improved significantly in CRT-D patients but remained unchanged in ICD patients. Patients with CRT-D implantation showed higher levels of depressive symptoms, psychological distress, and impairment in QoL at baseline and FU compared to ICD patients. These impairments remained mostly unchanged in all patients after 6 months. Overall, these findings imply that there is a need for careful assessment and treatment of psychological distress and depression in ICD and CRT-D patients in the course of device implantation as psychological burden seems to persist irrespective of physical improvement.

Reliability and availability evaluation of Wireless Sensor Networks for industrial applications.

PubMed

Silva, Ivanovitch; Guedes, Luiz Affonso; Portugal, Paulo; Vasques, Francisco

2012-01-01

Wireless Sensor Networks (WSN) currently represent the best candidate to be adopted as the communication solution for the last mile connection in process control and monitoring applications in industrial environments. Most of these applications have stringent dependability (reliability and availability) requirements, as a system failure may result in economic losses, put people in danger or lead to environmental damages. Among the different type of faults that can lead to a system failure, permanent faults on network devices have a major impact. They can hamper communications over long periods of time and consequently disturb, or even disable, control algorithms. The lack of a structured approach enabling the evaluation of permanent faults, prevents system designers to optimize decisions that minimize these occurrences. In this work we propose a methodology based on an automatic generation of a fault tree to evaluate the reliability and availability of Wireless Sensor Networks, when permanent faults occur on network devices. The proposal supports any topology, different levels of redundancy, network reconfigurations, criticality of devices and arbitrary failure conditions. The proposed methodology is particularly suitable for the design and validation of Wireless Sensor Networks when trying to optimize its reliability and availability requirements.

Reliability and Availability Evaluation of Wireless Sensor Networks for Industrial Applications

PubMed Central

Silva, Ivanovitch; Guedes, Luiz Affonso; Portugal, Paulo; Vasques, Francisco

2012-01-01

Wireless Sensor Networks (WSN) currently represent the best candidate to be adopted as the communication solution for the last mile connection in process control and monitoring applications in industrial environments. Most of these applications have stringent dependability (reliability and availability) requirements, as a system failure may result in economic losses, put people in danger or lead to environmental damages. Among the different type of faults that can lead to a system failure, permanent faults on network devices have a major impact. They can hamper communications over long periods of time and consequently disturb, or even disable, control algorithms. The lack of a structured approach enabling the evaluation of permanent faults, prevents system designers to optimize decisions that minimize these occurrences. In this work we propose a methodology based on an automatic generation of a fault tree to evaluate the reliability and availability of Wireless Sensor Networks, when permanent faults occur on network devices. The proposal supports any topology, different levels of redundancy, network reconfigurations, criticality of devices and arbitrary failure conditions. The proposed methodology is particularly suitable for the design and validation of Wireless Sensor Networks when trying to optimize its reliability and availability requirements. PMID:22368497

On the Mechanical Properties and Microstructure of Nitinol forBiomedical Stent Applications

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

Robertson, Scott W.

2006-01-01

This dissertation was motivated by the alarming number of biomedical device failures reported in the literature, coupled with the growing trend towards the use of Nitinol for endovascular stents. The research is aimed at addressing two of the primary failure modes in Nitinol endovascular stents: fatigue-crack growth and overload fracture. The small dimensions of stents, coupled with their complex geometries and variability among manufacturers, make it virtually impossible to determine generic material constants associated with specific devices. Instead, the research utilizes a hybrid of standard test techniques (fracture mechanics and x-ray micro-diffraction) and custom-designed testing apparatus for the determination ofmore » the fracture properties of specimens that are suitable representations of self-expanding Nitinol stents. Specifically, the role of texture (crystallographic alignment of atoms) and the austenite-to-martensite phase transformation on the propagation of cracks in Nitinol was evaluated under simulated body conditions and over a multitude of stresses and strains. The results determined through this research were then used to create conservative safe operating and inspection criteria to be used by the biomedical community for the determination of specific device vulnerability to failure by fracture and/or fatigue.« less

Use-related risk analysis for medical devices based on improved FMEA.

PubMed

Liu, Long; Shuai, Ma; Wang, Zhu; Li, Ping

2012-01-01

In order to effectively analyze and control use-related risk of medical devices, quantitative methodologies must be applied. Failure Mode and Effects Analysis (FMEA) is a proactive technique for error detection and risk reduction. In this article, an improved FMEA based on Fuzzy Mathematics and Grey Relational Theory is developed to better carry out user-related risk analysis for medical devices. As an example, the analysis process using this improved FMEA method for a certain medical device (C-arm X-ray machine) is described.

Atomtronics: Material and Device Physics of Quantum Gases

DTIC Science & Technology

matter physics to electrical engineering. Our projects title Atomtronics: Material and device physics of quantum gases illustrates the chasm we bridged...starting from therich and fundamental physics already revealed with cold atoms systems, then leading to an understanding of the functional materials

Left Ventricular Assist Device as a Bridge to Recovery for Patients With Advanced Heart Failure.

PubMed

Jakovljevic, Djordje G; Yacoub, Magdi H; Schueler, Stephan; MacGowan, Guy A; Velicki, Lazar; Seferovic, Petar M; Hothi, Sandeep; Tzeng, Bing-Hsiean; Brodie, David A; Birks, Emma; Tan, Lip-Bun

2017-04-18

Left ventricular assist devices (LVADs) have been used as an effective therapeutic option in patients with advanced heart failure, either as a bridge to transplantation, as destination therapy, or in some patients, as a bridge to recovery. This study evaluated whether patients undergoing an LVAD bridge-to-recovery protocol can achieve cardiac and physical functional capacities equivalent to those of healthy controls. Fifty-eight male patients-18 implanted with a continuous-flow LVAD, 16 patients with LVAD explanted (recovered patients), and 24 heart transplant candidates (HTx)-and 97 healthy controls performed a maximal graded cardiopulmonary exercise test with continuous measurements of respiratory gas exchange and noninvasive (rebreathing) hemodynamic data. Cardiac function was represented by peak exercise cardiac power output (mean arterial blood pressure × cardiac output) and functional capacity by peak exercise O 2 consumption. All patients demonstrated a significant exertional effort as demonstrated with the mean peak exercise respiratory exchange ratio >1.10. Peak exercise cardiac power output was significantly higher in healthy controls and explanted LVAD patients compared with other patients (healthy 5.35 ± 0.95 W; explanted 3.45 ± 0.72 W; LVAD implanted 2.37 ± 0.68 W; and HTx 1.31 ± 0.31 W; p < 0.05), as was peak O 2 consumption (healthy 36.4 ± 10.3 ml/kg/min; explanted 29.8 ± 5.9 ml/kg/min; implanted 20.5 ± 4.3 ml/kg/min; and HTx 12.0 ± 2.2 ml/kg/min; p < 0.05). In the LVAD explanted group, 38% of the patients achieved peak cardiac power output and 69% achieved peak O 2 consumption within the ranges of healthy controls. The authors have shown that a substantial number of patients who recovered sufficiently to allow explantation of their LVAD can even achieve cardiac and physical functional capacities nearly equivalent to those of healthy controls. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Valve system incorporating single failure protection logic

DOEpatents

Ryan, Rodger; Timmerman, Walter J. H.

1980-01-01

A valve system incorporating single failure protective logic. The system consists of a valve combination or composite valve which allows actuation or de-actuation of a device such as a hydraulic cylinder or other mechanism, integral with or separate from the valve assembly, by means of three independent input signals combined in a function commonly known as two-out-of-three logic. Using the input signals as independent and redundant actuation/de-actuation signals, a single signal failure, or failure of the corresponding valve or valve set, will neither prevent the desired action, nor cause the undesired action of the mechanism.

Remote management of heart failure using implantable electronic devices

PubMed Central

Morgan, John M.; Kitt, Sue; Gill, Jas; McComb, Janet M.; Ng, Ghulam Andre; Raftery, James; Roderick, Paul; Seed, Alison; Williams, Simon G.; Witte, Klaus K.; Wright, David Jay; Harris, Scott; Cowie, Martin R.

2017-01-01

Abstract Aims Remote management of heart failure using implantable electronic devices (REM-HF) aimed to assess the clinical and cost-effectiveness of remote monitoring (RM) of heart failure in patients with cardiac implanted electronic devices (CIEDs). Methods and results Between 29 September 2011 and 31 March 2014, we randomly assigned 1650 patients with heart failure and a CIED to active RM or usual care (UC). The active RM pathway included formalized remote follow-up protocols, and UC was standard practice in nine recruiting centres in England. The primary endpoint in the time to event analysis was the 1st event of death from any cause or unplanned hospitalization for cardiovascular reasons. Secondary endpoints included death from any cause, death from cardiovascular reasons, death from cardiovascular reasons and unplanned cardiovascular hospitalization, unplanned cardiovascular hospitalization, and unplanned hospitalization. REM-HF is registered with ISRCTN (96536028). The mean age of the population was 70 years (range 23–98); 86% were male. Patients were followed for a median of 2.8 years (range 0–4.3 years) completing on 31 January 2016. Patient adherence was high with a drop out of 4.3% over the course of the study. The incidence of the primary endpoint did not differ significantly between active RM and UC groups, which occurred in 42.4 and 40.8% of patients, respectively [hazard ratio 1.01; 95% confidence interval (CI) 0.87–1.18; P = 0.87]. There were no significant differences between the two groups with respect to any of the secondary endpoints or the time to the primary endpoint components. Conclusion Among patients with heart failure and a CIED, RM using weekly downloads and a formalized follow up approach does not improve outcomes. PMID:28575235

Assessing the Value-Added by the Environmental Testing Process with the Aide of Physics/Engineering of Failure Evaluations

NASA Technical Reports Server (NTRS)

Cornford, S.; Gibbel, M.

1997-01-01

NASA's Code QT Test Effectiveness Program is funding a series of applied research activities focused on utilizing the principles of physics and engineering of failure and those of engineering economics to assess and improve the value-added by the various validation and verification activities to organizations.