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Physical assets reliability is always called into question whenever manufacturing throughput is constrained by equipment availability. The equipment unavailability is generally attributed to functional failure, and one of the ensuing remedial actions to get the machine back to working condition is to institute repairs on the equipment. The degree of repair is scrutinized to give credence to the status of manufacturing assets on the ground, and the measure is focused on how perfect the repair was. A case study was carried out on a manufacturing firm to explore the different types of repairs that were being carried out on the manufacturing physical assets, aimed at understanding the factors that led to the choice of the repair type(s). The main focus of the study was on the application of perfect repair on physical assets, and the factors that prevented the organization from sticking to commitments of always instituting perfect repairs. The repercussions of not being able to institute perfect repairs were also assessed, and the understanding of optional remedies to ease the risk of further functional failures was also considered

Functional failure of total ossicular replacement prostheses (TORP) is often due to secondary displacement, ranging from simple subluxation to prosthesis extrusion following recurrence of severe tympanic membrane retraction. Several surgical techniques have been proposed to stabilize a TORP, mostly using superimposed non-organic or resorbable heterologous materials. We describe a simple so-called "tumulus" surgical technique that limits prosthesis displacement and extrusion, regardless of the type of TORP, by using a few fragments of autologous cartilage that are always available and perfectly tolerated at no cost. Review of 31 cases treated by this technique did not reveal any cases of prosthesis displacement and only one case (3.2%) of prosthesis extrusion with audiometric results comparable to the best results reported in the literature.

Degenerative diseases of the spine, when not solvable with clinical treatments or with suitable stabilization systems, can be cured by means of the technique of arthrodesis through the interbody fusion of two or more vertebrae. The paper deals with the tests carried out on commercial and innovative cervical cages, used in the primary stabilization of the vertebrae, able to maintain the right distance and to assure the interbody fusion. Additive manufacturing (AM) is a powerful new tool offering the necessary competitiveness to the biomedical manufacturing companies, having the possibility to create materials with controlled porosity combined with solid parts, providing to the workpiece excellent capacity in the subsequent phases of osseointegration. Based on the knowledge developed either in the biomechanics of the spine or in the properties of biocompatibility and osseointegration of titanium alloys, MT Ortho has developed some models of cervical cage made from modern additive printing techniques with titanium alloy. Three different cervical cage made of different materials were subjected to static compression test: a commercial cervical intervertebral cage in PEEK and two cervical intervertebral cages in Ti alloy produced by the EBM process by MT Ortho. Tests on the innovative cage produced by EBM have shown encouraging results. From this first preliminary analysis its showed that the mechanical and functional failure of the innovative devices made in melted Ti alloy by EBM is achieved by load values greater than physiological ones of the cervical spine.

In DEMO, the ex-vessel Remote Maintenance Systems (RMS) are responsible for the replacement and transportation of the plasma facing components. The ex-vessel operations of transportation (e.g. blankets or divertors) are performed by cranes or by means of trolleys. The blankets are extracted and transported vertically by cranes along galleries from the reactor to the storage or maintenance areas. An alternative is the transportation in horizontal configuration by means of trolleys along the galleries. A failure may occur in any situation, interrupting the current nominal operation. The work identifies a functional breakdown structure for the ex-vessel RMS operations and develops a Functional Failure Modes, Effects and Criticality Analysis (FFMECA). The results of the different FFMECA studies lead to the conclusions in terms of the most critical failure scenarios and the pros and cons of the horizontal versus the vertical transportation of blankets. In case of failure, a recovery procedure shall be triggered. The results will help the design process to improve and thus reduce the criticality index of the identified failures.

Permeable pavements are often affected by pore clogging, which leads to their functional failure and reduced service life. However, the clogging mechanism and its impact on the permeability and complex pore microstructures in pervious pavement remains unclear. The aim of current study is to quantify the clogging behavior in pervious pavement materials (PPMs) and carry out investigations on the development of pore characteristics and permeability. Novel Polyurethane bound Pervious Mixture (PUPM) were adopted for comparative study in present research with conventional Porous Asphalt (PA). The Aachen Polishing Machine (APM) was selected to perfectly serve as a simulator for clogging process of pavement in the actual service condition. The permeability and pore microstructure of the pervious pavement material was then characterized by using the self-developed permeameter and X-ray Computed Tomography (CT) scanning respectively. The development of pore characteristics in terms of clogging was experimentally illustrated. The developed experiments and analysis can further strengthen the understanding of the clogging mechanism within the porous pavement material. The results can also serve for the optimization of the pervious pavement design in the engineering application.

Helium Cooled Pebble Bed (HCPB) blanket concept is one of the DEMO (Demonstration Power Plant) blanket concepts running for the final design selection. Concept relevant safety needs to be addressed at the early stage of the design. In this paper the preliminary safety studies for the current concept have been performed with respect to the FFMEA (Functional Failure Mode and Effect Analysis), the confinement strategy, identification of source terms, and selection of critical event sequences. © 2015 Elsevier B.V. All rights reserved.

Ischemia and reperfusion (I/R) are of fatal consequence for the affected organs, as they provoke a profound inflammatory reaction. This thoroughly destroys cells and tissues, inducing functional failure or even complete loss of organ function. Since I/R is primarily a vascular problem, the interaction between the endothelium and the surrounding environment is of great significance. The angiopoietins (ANG) and the TIE receptors are key players for the vascular homeostasis. This review summarizes biochemical and cellular mechanisms leading to I/R injury. After a brief introduction to the ANG/TIE system, a comprehensive overview of its role for the development of I/R syndrome is given. Finally, current therapeutic approaches to mitigate the consequences of I/R by modulating ANG/TIE signaling are reviewed in detail.

Background Male and female condom (FC) functional performance failure declines with user experience. With the recent availability of a wider range of FCs, it is important to know if women with experience in using one type of FC are more proficient in using another type, even if the FC design is quite different. Study design A randomized, noninferiority crossover clinical trial assessed the function of four FCs (FC2, Woman's Condom, Cupid and VA w.o.w) among 300 women in Durban, South Africa. FC functional failure (breakage, slippage, invagination and misdirection) by condom type and use period was investigated in women using five FCs of each type (20 FC uses in total). Results Of the 5364 condoms used during intercourse by 272 women, 200 clinical failures occurred in 195 condoms (190 condoms had one failure, and 5 had two failures). Total clinical failure was comparable across FC types. Of the 195 condoms in which failures occurred, the number of failures in the first condom use period was 103 (7.7%), decreasing to 43 events (3.2%) in the second, 33 (2.5%) in the third and 16 (1.2%) in the fourth. Only 2 failures were reported in the 20th use of an FC compared to 29 in the first use, irrespective of condom type. Conclusions FC failure rates decreased markedly after use of the first five condoms regardless of FC type and continued to fall across the next three use periods. Implications FC failure rates decrease over 20 uses, regardless of FC condom type used. The decrease is higher at the beginning of use, indicating that improvement is greatest after the first five uses.

Water pipes corrode as the endurance period elapses, or become deteriorated according to the buried environment, sometimes causing functional failure and problems with stable water supply. Stable and continuous water supply for consumers requires the risk assessment of water pipes. The safety factor has been used in many fields as a direct evaluation index that can express the state of a facility and is also used as a reference to judge the necessity of pipe renewal. In this study, the safety factor was calculated in order to establish the Probability of Failure model, by using result data such as the pipe property and ratio of residual stress from the technological inspection of waterworks.

Objective To evaluate multi-institutional outcomes of bulbar urethroplasty utilizing a standardized cystoscopic follow-up protocol. Methods Eight reconstructive surgeons prospectively enrolled urethral stricture patients in a multi-institutional study and performed postoperative cystoscopy at 3 and 12 months. Anatomic failure was defined as the inability to pass a flexible cystoscope without force. Functional failure was defined as the need for a secondary procedure. Men not compliant with the 12-month cystoscopy were called and asked if any interval secondary procedures had been performed. Patients with bothersome voiding complaints at cystoscopy were considered symptomatic. Results Of 213 men in study, 136 underwent excisional urethroplasty (excision and primary anastomosis [EPA]) and 77 underwent repair with buccal grafts. Cystoscopy compliance was 79.8% at 3 months and 54.4% at 12 months. Anatomic success rates were higher at 3 vs 12 months for EPA repairs (97.2% [106 of 109] vs 85.5% [65 of 76; P = .003] but not buccal repairs (85.5% [53 of 62] vs 77.5% [31 of 40]; P = .30). Functional success rates at a year were higher but statistically similar to anatomical success rates (EPA—90.3% [93 of 103]; P = .33; buccal—87% [47 of 54]; P = .22). Of the 20 anatomic recurrences, only 13 (65%) were symptomatic at the time of cystoscopic diagnosis. Conclusion Rates of success are lower when using the anatomic vs traditional definition. Of recurrences found by cystoscopy, only 65% were symptomatic. One-year patient cystoscopy compliance was poor and its ability to be used as the gold standard screening methodology for recurrence is questionable.

An increased focus on risk based maintenance (RBM) optimization has been prompted in the offshore oil and gas (O&G) production and process industry due to the currently existing regulations and guidelines on preventing the functional failure risk (FFR) of rotating equipment and instrumentation. The RBM optimization approach prioritizes functions based on the potential risk of a given functional failure. Then, the equipment and instrumentation connected to the different functions are assigned with appropriate maintenance routines according to the potential risk of corresponding functional failure. This manuscript focuses on mitigating the suboptimal prioritizations made in implementing petroleum safety authority (PSA) specified regulations and NORSOK standard Z008 specified guidelines. It is mandatory to follow these to prevent functional failures on offshore O&G production and process facilities (P&PFs) operational on the Norwegian Continental Shelf (NCS). This manuscript suggests a fuzzy inference system (FIS) to minimize the suboptimal prioritizations of functions in the FFR analysis using an illustrative tailor-made risk matrix. This risk matrix has been developed to be similar to currently existing tailor-made risk matrices that have derived from Z008 guidelines and which have been used for FFR in different P&PF owner organizations operational on the NCS. Membership functions and the rule base were developed utilizing Z008 guidelines, data, experience, intuition and intentions of maintenance engineers. A risk rank calculation has been performed using the suggested FIS. The results indicate how the proposed approach helps in simplifying and making a more reliable and uniform FFR estimation.

This study examined social capital as a means of accessing resources embedded in social ties and aimed to debate its character in the context of informal support in post-disaster recovery. The three following issues were examined: (1) How respondents obtain disaster resources from social capital (including the bonding and bridging types of social capital), (2) why certain individuals have less informal support (e.g., the relationship between informal support and dynamic social capital), and (3) the relationship between social capital and recovery satisfaction according to previous studies on cognitive social capital and satisfaction. A questionnaire was thus conducted on the island of Izu-Oshima after it incurred serious damage due to a typhoon (no. 26) that struck in 2013. This study's findings were as follows: (1) Bonding social capital support resulted in various and major forms of support during post-disaster recovery. Notably, neighbors and friends utilized the flow of information to find support. Bridging social capital complemented supplies and partial psychological support when bonding social capital experienced functional failure during the same disaster. (2) Those who increased contact through bonding social ties (e.g., neighbors, friends, and coworkers living in the same community) had higher various support rates after the disaster. (3) Those who accepted informal support and had higher levels of government trust had significantly positive results for recovery satisfaction.

Hip osteoarthritis is a chronic disease affecting the joint and surrounding musculature resulting in structural and functional failure of the joint and causing pain, disability, and reduced quality of life. This narrative review outlines the prevalence and burden of hip osteoarthritis followed by its natural history and risk factors. Considerations for diagnosis and assessment are then covered. An overview of the principles of hip osteoarthritis management is presented together with specific physiotherapy interventions and evidence for their effectiveness. It is important to note, however, that the bulk of research regarding conservative management relates to osteoarthritis at the knee or mixed osteoarthritis populations rather than hip osteoarthritis specifically, and that results cannot necessarily be generalised from the knee to the hip given differences in biomechanics, presentation, and risk factors. There is also a paucity of research in many areas. The recommendations of clinical guidelines are therefore emphasised. The review concludes with potential directions for research to advance the field.

A numerical/experimental study was conducted to investigate the failure pressure of filament wound composite tubes subjected to internal pressure. A progressive failure analysis was performed using ABAQUS (version 6.7) commercial software employing an alternative damage model implemented by the user subroutine (UMAT). Four thin-walled E-glass fiber epoxy tubes with different wind angles were produced and tested for the closed-end loading condition. Unlined tubes were initially tested to obtain the leakage failure and then lined with PVC tubes for burst failure pressure. The tests were conducted in a high pressure system specifically built for this work. Numerical and experimental results were compared and showed good correlation for all fiber wound orientations investigated.

Background The main purpose of the study was to report a comparative experience with primary and secondary esophagocoloplasty for caustic injuries. Secondary esophagocoloplasty is the main rescue option after graft loss, but data in the literature are scarce. Methods The operative characteristics, postoperative course, and functional outcomes of 21 secondary and of 246 primary esophagocoloplasty operations performed for caustic injuries between 1987 and 2006 were compared. Intraoperative events requiring significant changes in the planned operative strategy, such as graft ischemia or necrosis, were recorded. Statistical tests were performed in both cohorts to identify factors predictive of postoperative graft necrosis. Univariate analysis was performed to identify factors predictive of functional failure after secondary esophagocoloplasty. Results Operative mortality (5% vs 4%, p = 0.56), morbidity (62% vs 59%, p = 0.96), postoperative graft necrosis (14% vs 7%, p = 0.16), and functional success (68% vs 70%, p = 0.79) rates of the secondary and primary esophagocoloplasty operations were similar. Intraoperative graft ischemia at the time of secondary esophagocoloplasty was significantly associated with the risk of postoperative graft necrosis ( p = 0.015) and functional failure ( p = 0.046). At the time of primary esophagocoloplasty, intraoperative necrosis of the colon was the only independent predictive factor of postoperative graft necrosis ( p Conclusions Secondary esophagocoloplasty is a safe and reliable salvage option after primary graft loss in patients with caustic injuries. Delayed esophagocoloplasty should be considered if intraoperative colon necrosis occurs at the time of primary reconstruction.

A methodology of tsunami PSA was developed in this study. A tsunami PSA consists of tsunami hazard analysis, tsunami fragility analysis and system analysis. In the case of tsunami hazard analysis, evaluation of tsunami return period is a major task. For the evaluation of tsunami return period, numerical analysis and empirical method can be applied. In this study, tsunami return period was evaluated by empirical method using historical tsunami record and tidal gauge record. For the performing a tsunami fragility analysis, procedure of tsunami fragility analysis was established and target equipments and structures for investigation of tsunami fragility assessment were selected. A sample fragility calculation was performed for the equipment in Nuclear Power Plant. In the case of system analysis, accident sequence of tsunami event is developed by according to the tsunami run-up and draw down, and tsunami induced core damage frequency (CDF) is determined. For the application to the real Nuclear Power Plant, the Ulchin 56 NPP which located in east coast of Korean peninsula was selected. Through this study, whole tsunami PSA working procedure was established and example calculation was performed for one of real Nuclear Power Plant in Korea. But for more accurate tsunami PSA result, there are many researches needed for evaluation of hydrodynamic force, effect of debris, structural failure probability of break water structure and intake structure, functional failure criteria for offsite power.

In order to establish an effective ITER atmosphere detritiation system (DS), JAEA (Japan Atomic Energy Agency) has investigated the performance and the durability of the system at various incident/accident conditions in support of finalizing the DS conceptual design through the ITER design review. The current DS as the Safety Important Component (SIC) has been discussed and mainly consists of catalytic reactors, wet scrubber columns (SCs), and blowers. The functional failure of the DS designed with SC was evaluated using a database of failure experiences of various valves, controllers, and components. Regarding the tritium release into the biggest confinement sector of the Tokamak gallery, this design is improved by more than two orders of magnitude compared to the original DS designed with molecular sieves (MSs) dryer beds in the 2001 design report. This improvement is achieved mainly by the reduction of frequency of valve operation, like MS dryers requiring periodical regeneration, and by the standardized module arrangement of the DS with SC.

An item is subject to gradual degradation. The degradation can be represented by a measurable, non-negative and non-decreasing quantity. The item can be in one of three different states: normal (when the degradation quantity is smaller than a threshold of alarm or potential failure), functional failure (when the degradation quantity is larger than a functional failure threshold) and in-between or potential failure (when the degradation quantity is larger than the alarm threshold and smaller than the functional failure threshold). A sequential inspection scheme is implemented to determine the state of the item so as to prevent a functional failure. The paper presents a flexible degradation model and two cost models to optimize the alarm threshold and the sequential inspection scheme. The usefulness and appropriateness of the proposed models are illustrated by examples.

Passive systems are increasingly deployed in nuclear industry with an objective of increasing reliability and safety of operations with reduced cost. Methods for assessing the reliability of thermal–hydraulic passive systems, that is systems with moving working fluid, address the issues in natural buoyancy-driven flow that could result in a failure to meet the design safety limits under accident scenarios. This is referred as design functional reliability. This paper presents the results of functional reliability analysis carried out for the passive Safety Grade Decay Heat Removal System (SGDHRS) of Indian Prototype Fast Breeder Reactor (PFBR). The analysis is carried out based on the overall approach reported in the Reliability Methods for Passive System (RMPS, European Commission) project. Functional failure probability is calculated using Monte-Carlo method and also with method of moments.

Soft defect localization (SDL) is an analysis technique where changes in the pass/fail condition of a test are monitored while a laser is scanned across the device under test (DUT). This technique has proven its usefulness for quickly locating defects that are temperature, frequency, and/or voltage dependant, for example, scan logic soft fault. However, due to high sensibility at analogue circuits SDL meets great challenges. This work gives a new flow to analyze soft functional failure in advanced logic products using fault based analogue simulation and SDL. The paper will present one case study illustrating the application of analogue simulation based soft defect localization flow as an effective means to achieve fault isolation.

This paper presents a failure analysis of real industry case using FMECA method. The case study is conducted in a tyre manufacturing industry focusing on the machine components mechanism failures. Field failures record data are systematically analyzed to identify and classify the failure modes, effects and determined the criticality index on the subject under study. The details of step-by-step in applying FMECA according to the case study, the resultsand discussion have been presented accordingly. It is then concluded and proved that the FMECA method is beneficial to rank and prioritize failures systematically and thus help engineering team to perform the improvement project based on the right problem. Keywords : Failure analysis, Industry case study, Failure Mode Effect and Criticality Analysis (FMECA) 1. Introduction Every machine and process in daily manufacturing operations has it owns modes of failure. These modes of failures are where the state of termination of the ability of an item of any part, component, device, subsystem, functional unit, component or system that can be individually considered, to perform a required function takes in place as per definition by SS-EN 13306 [1]. In short, there are two types of failure which are the functional failure and the potential failure. A functional failure is the inability of an item or the component containing itto meet a specified performance standard meanwhile the potential failure is an identifiable physical condition which indicates a functional failure is imminent by referring to Nowlan and Heap [2].

International audience; Atomic force measurements were performed on supported pulmonary surfactant (PS) films to address the effect of cholesterol on the physical properties of lung surfactant films. We recently found that cholesterol in excess of a physiological proportion abolishes surfactant function, and is the reason that surfactant fails to lower the surface tension upon compression. In this study, we investigated how the loss of mechanical stability observed earlier is related to the local mechanical properties of the film by local force measurements. The presence of 20% of cholesterol in bovine lipid extract surfactant (BLES) resulted in a decrease of the observed adhesive interaction, and an increase in rigidity of the film. We discuss the implication the increased rigidity might have on the functional failure of PS.

The functional failure of an idle air control valve in a gasoline-fuelled automobile in India has been analyzed. It was found that the failure was related to the formation of deposits inside the idle air control valves. The deposit was found to contain both organic and inorganic constituents. The deposits were characterized using a variety of techniques including chemical analysis, optical microscopy, FTIR spectroscopy, GC–MS, X-ray diffraction and thermal analysis. The possible source of the deposit formation has been analyzed. It is inferred that the cause of deposit formation and the subsequent failure of the idle air control valve is because of the back flow and condensation of fuel vapor combined with contamination through extraneous dirt especially silica from the air intake system.

Microlamination involves the patterning, registration and bonding of thin layers of material, called laminae, to produce monolithic devices with embedded micro-scale features. In energy, chemical and biological systems miniaturization, microlamination can be used to produce bulk microfluidic devices for mobile, compact or point-of-use applications. Thermally-Enhanced Edge Registration (TEER) is a registration technique used in metallic microlamination to precisely align laminae during high-temperature bonding cycles. Shape variation, such as channel misalignment or fin buckling, incurred during the TEER registration step can lead to lower system performance or even functional failure. This paper investigates the allowable tolerance limits in TEER fixtures in order to minimize fin buckling while attaining precise alignment. A high-temperature buckling model is developed to predict the onset of fin buckling within a TEER fixture. The results of the model are validated empirically. Results indicate that within the tolerance limits, micrometer-scale channel-to-channel alignment can be achieved free of fin buckling. In addition, the general relationship between the critical point of buckling and the device configuration is discussed for broader application.

Background/Purpose: The purpose of this study was to review the authors' 25-year experience with redo pull-through procedures for Hirschsprung's disease including surgical technique and long-term outcome. Methods: From 1974 to now, over 325 patients with Hirschsprung's disease have been treated at C.S. Mott Children's Hospital. This includes 30 patients referred after an unsuccessful pull-through at another hospital and 2 patients with an unsuccessful pull-through from C.S. Mott. All redo pull-throughs (n = 19) were performed in these patients, and their clinical courses are reviewed. Results: Twelve patients required reoperation secondary to a mechanical problem with their first pull-through. The other 7 patients had evidence of residual segments of dilated colon leading to functional failure of their initial operation including 5 patients with documented aganglionic bowel present at the second pull-through. Ten of the patients requiring reoperation initially had an endorectal pull-through (ERPT), 5 had a Duhamel procedure, 3 had a Swenson procedure, and 1 had a Rehbein procedure. Choice of revision was an ERPT in 8 patients in whom an adequate rectal cuff could be developed. Additional redo procedures included a Duhamel in 8 patients and a Swenson in 3 patients. Follow-up ranges from 3 months to 23 years (mean, 13.8 years). There were no deaths in the series, and 1 patient required a third pull-through. All patients who are not neurologically impaired and are over age 3 are continent except one (94%). Stools per day range from 1 to 10 (mean, 3.2). Conclusions: Redo pull-through operations for Hirsch-sprung's disease appear to be as effective as primary procedures in terms of continence and stooling frequency. Distinct from other series, we found an ERPT to be the procedure of choice if an adequate rectal cuff was present. J Pediatr Surg 35:829-834. Copyright © 2000 by W.B. Saunders Company.

Objectives: Fascia lata allografts are commonly used in urogynecologic procedures. Functional failure of several grafts has occurred, and such failure has been recognized as a materials problem in 12 patients. Study Design: Twelve patients with failure of an initial urogynecologic procedure performed with irradiated and freeze-dried donor fascia lata grafts underwent reoperation. Portions of the implanted fascia lata grafts could be retrieved in 7 cases. Graft specimens underwent histologic processing followed by hematoxylin and eosin staining. Results: Histopathologic analyses of the retrieved material demonstrated several ongoing processes in the failed grafts. A few grafts showed areas of ideal remodeling. Most grafts, however, showed areas of disorganized remodeling and areas of graft degeneration. Evidence of immune reaction to the graft was observed in some cases. Conclusion: The high materials failure rate associated with the use of irradiated and freeze-dried donor fascia lata grafts suggests that such tissue should not be used for urogynecologic procedures. (Am J Obstet Gynecol 1999;181:1339-46.)

This study documents the functional failure of a concrete lined steel sewage pipe. Symptoms of the pipe failure are presented. Failure of the pipe system can be attributed to incompatibility between the mechanical behavior of the pipe and the methodology employed in its design. The underlying cause of the failure may be traced to a lack of sufficient backfill stiffness. In situ testing was used to evaluate the stiffness of the side backfill. The existing pipe–trench system condition was analysed numerically and a criterion developed for the consideration of the structural integrity of the pipeline.

As lifesaving devices, implantable cardioverter-defibrillators (ICDs) and leads used with ICD systems require the highest possible standards of reliability. Despite meticulous design, careful manufacturing, and rigorous testing, ICDs and leads have finite rates of failure. ICD leads are designed to transfer information to, and life-sustaining therapy from, the ICD in the hostile and mechanically stressful intravascular and cardiac environment of the human body. With the high-profile failure of multiple ICD lead models over the last several years, they now are considered a “weak link” in the ICD systems, just as pacemaker leads are in pacing systems. The result has been to undermine trust in ICD therapy. Recommendations for timely detection, characterization, communication, and correction of product lead performance issues were developed to provide a systematic approach to improve lead reliability. Definitions of ICD lead malfunction, performance, and reliability have been standardized to allow comparison of leads. Lead reliability represents the measure of freedom of a specific lead from structural or functional failure as a function of time. This time dependence of assessing lead performance represents 1 of many ongoing challenges. Manufacturer product performance reports and independent registries are significantly limited by underreporting of lead malfunction, insufficient patient follow-up, lack of uniform definitions, lack of returned product for fault analysis, and a passive monitoring system based on voluntary reporting. Multiple recommendations related to lead performance, communication, premarket evaluation, postmarket surveillance, lead advisories, and clinical management have been advanced. The responsibilities of the many stakeholders in addressing acknowledged limitations of ICD lead design, testing, manufacturing, surveillance, reporting, and improvement are clearly specified. Cooperation among manufacturers, regulatory agencies, physicians, and patients is critical to establish and maintain trust in all of these areas.

The article by Barzokis is a well-argued, insightful thesis that challenges us to consider novel views of the aging and diseased brain. The particular strength of this article is that it should succeed in bringing to the forefront of our thinking an appreciation for the high degree of metabolic activity and concomitant energy cost associated with maintaining a heavily myelinated brain and how aging or aging with disease may impact on or be impacted by this process. White matter has a number of essential metabolic processes that are ongoing throughout life yet the vascular supply is less extensive than the gray matter. This relationship between demand for nutrient support and limited access to nutrients requires development of storage devices (e.g. high ferritin content of oligodendrocytes for iron storage) and increases the likelihood of functional failure following any event associated with compromise in nutrient delivery. The types of neurological events in which white matter involvement is seen are detailed in the Bartzokis article. However, frequently the white matter involvement is considered secondary or of less neurological consequence than accompanying gray matter damage. Perhaps, in view of the strong supporting data discussed in the Bartozkis article, the white matter involvement will be given greater consideration. As argued, continual degradation of white matter and fragmentation of myelin could result in continued or exacerbation of an inflammatory reaction that could prove resistant to therapeutic interventions that do not specifically target this region. The relationships to memory consolidation and myelination are particularly noteworthy in considering myelin deficits and cognitive function in Alzheimer’s disease (AD). Although the article was necessarily focused on white matter and hence white matter oligodendrocytes, the potential contribution of gray matter oligodendrocytes to myelin, cholesterol and iron metabolism are also relevant to the concepts set forth. The argument that oligodendrocytes have a high energy requirement and associated high iron requirement can be supported further than the studies referenced in the Bartzokis

This paper describes fragility evaluation results estimated by a seismic PRA procedure on the structural and functional failure of a building and equipment. The applicability of the response estimation method of the seismic PRA procedure is also discussed. The probability of failure is evaluated by a previously established PRA procedure and by Monte Carlo simulation. The response is calculated by five different methods in order to study the characteristics of simplified factors of the PRA procedure. According to the results, it is concluded that the proposed seismic PRA procedure gives adequate results when compared with the Monte Carlo simulation method. The PRA procedure can be used for a simplified evaluation method.

An evaluation methodology for seismic base isolated nuclear equipments is proposed. The evaluation can be classified into two steps. In the first step, the seismic functional failure probability during the lifetime of equipment without base isolation devices is quantified in order to decide the applicability of the base isolated structure. The second step is comparative and calculates the ratio of the seismic failure frequency of the equipment without base isolation devices to that with them in order to evaluate the effectiveness of the base isolated structure. The sample evaluation considers the case of high voltage type emergency transformer with ceramic tubes.

espanolIntroduccion: El ojo seco es una enfermedad en la que entre otras estructuras se afecta el epitelio corneal. El tratamiento de primera linea siguen siendo los sustitutivos lagrimales que buscan lograr una buena humidificacion y lubricacion del epitelio corneal de estos pacientes, evitando asi su progresivo deterioro funcional. El HP-Guar es un compuesto novedoso cuyos resultados sintomaticos en los pacientes con ojo seco estan siendo prometedores. Metodos: Presentamos un estudio prospectivo, enmascarado, pareado sobre 10 ojos izquierdos de 10 pacientes con ojo seco, a los que se les realizo medidas de la permeabilidad corneal mediante fluorofotometria con la instilacion de 40 microlitros de una solucion de fluoresceina sodica al 2%, antes y despues del tratamiento con HP-Guar. Se analizaron los resultados con el test de Wilcoxon para datos pareados. Resultados: Se observo tuvo una disminucion estadisticamente significativa de la permeabilidad corneal media del 45% tras tratamiento con HP-Guar (p= 0,002). Conclusiones: El HP-Guar constituye una nueva opcion terapeutica que ha demostrado fluotofotometricamente reducir la permeabilidad epitelial corneal tras su uso. EnglishIntroduction: The incidence of dry eye disease, which mainly affects the corneal epithelium, is rising. The main treatment is still the use of artificial tears capable of improving the humidification and lubrication of the corneal epithelium, and avoiding its progressive functional failure. HP-Guar is a new compound used for this purpose. Methods: We performed a prospective, masked and paired study on the left eye of 10 patients suffering from dry eye disease. Corneal permeability measurements were performed by fluorophotometry after instilling 40 µL of a solution of 2% sodium fluorescein, before and after treatment with the HP-Guar drops. The results were analysed using Wilcoxon test for paired data. Results: A mean decrease in corneal permeability of 45%, after the use of HP-Guar drops was found (p=0.002). Conclusions: HP-Guar provides a new therapeutic option significantly decreasing corneal epithelial permeability.

It is a common clinical misconception to regard the spinal micturition reflex center as fundamentally overactive and dependent on cerebral inhibition. Initiation and cessation of micturition is simplistically viewed as a manifestation of voluntary withdrawal and resumption of inhibitory corticospinal "regulation''. This view is in conflict with basic neurophysiologic experimental data. Actually, the organization of the micturition reflex is extremely complex. It is affected by multiple sources of facilitative and inhibitory influence, peripheral as well as central. During the past half century, at least twelve reflexes involved in urine storage and coordinated micturition have been described by various neurologic investigators. In this article the integral reflexes are identified and described. A functional organization of the integral reflexes which includes a modern concept of their role in the physiology of urine storage and micturition is presented. It is implicit that overactivity or functional failure of any one or combination of the integral reflexes may cause a significant disorder of lower urinary tract function.

A total of 255 patients of 281 patients with side-to-side epididymovasostomy for post pathologic epididymal obstruction were followed from 1964 to 1983. The success rates were higher in patients with nontuberculous epididymitis than in those with tuberculous epididymitis. There were no significant differences among anastomotic levels of the epididymal incision. The success rates were 31% for patency and 12% for pregnancy in the 97 patients with macrosurgery and 37% for patency and 20% for pregnancy in the 158 with microsurgery. The causes of anatomic failure were scar formation at the anastomotic site and blockage of opening of the original epididymal tubule. The cause of functional failure was poor semen quality after epididymovasostomy.

Functional failure of venous valves is the central pathologic fault in varicose veins. Stripping of the saphenous vein has given good results; sclerotherapy is less successful but is useful in some situations.

The present experiments were conducted on isolated dog hearts to demonstrate that conduction disturbances can be induced in the bundle branches by transection of about 50 per cent of the cross-sectional area of the His bundle on the right or left side. The His bundle, the posterior and anterior divisions of left bundle, and the right bundle were exposed by careful dissection, and microelectrode techniques were used to record action potentials from the three bundle branches. Pacing stimuli were applied to the nonbranching portion of His bundle proximal and then distal to the site of transection to study the effect of such lesions on impulse conduction to the bundle branches. It was demonstrated that conduction to the bundle branches was not affected by such lesions in the His bundle at pacing rates slower than 100 per minute; however, conduction disturbances were rate-dependent and manifested at faster pacing rates. In nine out of all 16 experiments, partial or complete block occurred in all three bundle branches regardless of the side of the lesion. In the remaining seven experiments, they were observed in the bundle branch on the same side as the lesion. It was assumed that conduction disturbances of the bilateral bundle branches resulted from decremental conduction in the uncut portion of His at the level of lesion, and those of the ipsilateral branch from the functional failure of transverse crossover connections between the longitudinal His bundle fibers. The results indicate that localized lesions in the nonbranching portion of His bundle can indeed produce the pattern of bundle branch block under certain conditions.

The authors report a retrospective review of 407 eyes that received intravitreal liquid silicone between 1961 and 1984. Initial anatomical success was noted in 270 eyes (66.3%), while initial functional success was achieved in 103 eyes (25.3%). Ten years postoperatively, approximately half of the eyes with initial functional success still had functional vision (49.2%). These eyes had less advanced proliferative vitreoretinopathy and fewer inferior breaks than others. Recurrent retinal detachment rather than late complications was the predominant cause of functional failure in those eyes losing functional vision in less than ten years postoperatively. Late complications were common and frequently required therapeutic intervention. Intravitreal liquid silicone was of great benefit to many monocular patients, but of little benefit to the binocular patients in our series.

The achievement of correct vertical dimension is one of the most neglected steps in the preparation for complete den­ tures when compared with the highly improved methods of obtaining impres­ sions, centric relation or articulation. Nevertheless, the procedure to establish vertical dimension is as important as any other; an error in its determination may lead to esthetic and functional failure of the prosthesis and may also be an impor­ tant factor in alveolar resorption.

Eight patients were reviewed after intestinal cystoplasties had been performed for a variety of causes. Failure to establish an efficient voiding pattern in the immediate postoperative period was the principal cause of functional failure. Cystometrograms reveal different patterns for success and failure.