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Sample records for predict extubation failure

  1. Abnormal Breathing Patterns Predict Extubation Failure in Neurocritically Ill Patients

    PubMed Central

    Punj, Pragya; Nattanmai, Premkumar; George, Pravin

    2017-01-01

    In neurologically injured patients, predictors for extubation success are not well defined. Abnormal breathing patterns may result from the underlying neurological injury. We present three patients with abnormal breathing patterns highlighting failure of successful extubation as a result of these neurologically driven breathing patterns. Recognizing abnormal breathing patterns may be predictive of extubation failure and thus need to be considered as part of extubation readiness. PMID:28348899

  2. Etiology of extubation failure and the predictive value of the rapid shallow breathing index.

    PubMed

    Epstein, S K

    1995-08-01

    Failure of weaning from mechanical ventilation is thought to result from an imbalance between respiratory muscle capacity and respiratory demand. The ratio of respiratory rate to tidal volume (f/VT, rapid shallow breathing index) during spontaneous unsupported respiration increases when this imbalance exists, and may predict the success or failure of weaning from mechanical ventilation. Using f/VT, Yang and Tobin demonstrated a positive predictive value (PPV) of 0.78 (f/VT < or = 105 and weaning success) (1). To define the etiology of the 20% false-positive rate (FPR, f/VT < or = 105 and weaning failure), 94 patients who had an f/VT determined prior to extubation were studied prospectively. Of 84 patients with an f/VT < 100, 14 required reintubation within 72 h of extubation (FPR = 0.17, PPV = 0.83). Extubation in 13 of these 14 cases failed because of congestive heart failure, upper airway obstruction, aspiration, encephalopathy, or the development of a new pulmonary process. Only one patient needed reintubation solely because of the original respiratory process. Of 10 patients extubated with an f/VT > or = 100, four required reintubation, all because of the underlying respiratory process. This study confirms the high PPV for an f/VT < 100. The FPR of approximately 0.20 is best explained by extubation failure caused by processes for which f/VT is physiologically or temporally unlikely to predict success or failure. The negative predictive value (f/VT > or = 100 but extubation success) for f/VT may be lower than previously reported.

  3. Usefulness of full outline of unresponsiveness score to predict extubation failure in intubated critically-ill patients: A pilot study

    PubMed Central

    Said, Tarek; Chaari, Anis; Hakim, Karim Abdel; Hamama, Dalia; Casey, William Francis

    2016-01-01

    Objective: To assess the usefulness of the full outline of unresponsiveness (FOUR) score in predicting extubation failure in critically ill intubated patients admitted with disturbed level of conscious in comparison with the Glasgow coma scale (GCS). Patients and Methods: All intubated critically ill patients with a disturbed level of consciousness were assessed using both the FOUR score and the GCS. The FOUR score and the GCS were compared regarding their predictive value for successful extubation at 14 days after intubation as a primary outcome measure. The 28-day mortality and the neurological outcome at 3 months were used as secondary outcome measures. Results: Eighty-six patients were included in the study. Median age was 63 (50–77) years. Sex–ratio (M/F) was 1.46. On admission, median GCS was 7 (3–10) while median FOUR score was 8.5 (2.3–11). A GCS ≤ 7 predicted the extubation failure at 14 days after intubation with a sensitivity of 88.5% and specificity of 68.3%, whereas a FOUR score <10 predicted the same outcome with a sensitivity of 80.8% and a specificity of 81.7%. The areas under the curves was significantly higher with the FOUR score than with GCS (respectively 0.867 confidence interval [CI]: 95% [0790–0.944] and 0.832 CI: 95% [0.741–0.923]; P = 0.014). When calculated before extubation, FOUR score <12 predicted extubation failure with a sensitivity of 92.3% and a specificity of 85%, whereas a GCS <12 predicted the same outcome with a sensitivity of 73% and a specificity of 61.7%. Both scores had similar accuracy for predicting 28-day mortality and neurological outcome at 3 months. Conclusion: The FOUR score is superior to the GCS for the prediction of successful extubation of intubated critically ill patients. PMID:28149821

  4. Predictors of extubation failure and reintubation in newborn infants subjected to mechanical ventilation

    PubMed Central

    Costa, Ana Cristina de Oliveira; Schettino, Renata de Carvalho; Ferreira, Sandra Clecêncio

    2014-01-01

    Objective To identify risk factors for extubation failure and reintubation in newborn infants subjected to mechanical ventilation and to establish whether ventilation parameters and blood gas analysis behave as predictors of those outcomes. Methods Prospective study conducted at a neonatal intensive care unit from May to November 2011. A total of 176 infants of both genders subjected to mechanical ventilation were assessed after extubation. Extubation failure was defined as the need to resume mechanical ventilation within less than 72 hours. Reintubation was defined as the need to reintubate the infants any time after the first 72 hours. Results Based on the univariate analysis, the variables gestational age <28 weeks, birth weight <1,000g and low Apgar scores were associated with extubation failure and reintubation. Based on the multivariate analysis, the variables length of mechanical ventilation (days), potential of hydrogen (pH) and partial pressure of oxygen (pO2) remained associated with extubation failure, and the five-minute Apgar score and age at extubation were associated with reintubation. Conclusion Low five-minute Apgar scores, age at extubation, length of mechanical ventilation, acid-base disorders and hyperoxia exhibited associations with the investigated outcomes of extubation failure and reintubation. PMID:24770689

  5. Perioperative Predictors of Extubation Failure and the Effect on Clinical Outcome After Infratentorial Craniotomy.

    PubMed

    Cai, Ye-Hua; Wang, Hai-Tang; Zhou, Jian-Xin

    2016-07-12

    BACKGROUND The purpose of the study was to analyze the risk factors for failed extubation in subjects submitted to infratentorial craniotomy. MATERIAL AND METHODS Patients aged over 18 years who received infratentorial craniotomy for brain tumor resection were consecutively included in this study. Perioperative variables were collected and analyzed. Univariate analyses and multiple logistic regression were used to derive factors related to failed extubation. Patients had follow-up care until either out of hospital or death. RESULTS Throughout the course of the study, 2118 patients were eligible and 94 (4.4%) suffered from extubation failure at some point during their hospital stay. Five factors were recognized as independent risk factors for postoperative failed extubation: craniotomy history, preoperative lower cranial nerve dysfunction, tumor size, tumor position, and maximum change in blood pressure (BP) during the operation. Failed extubation was related to a higher incidence rate of pneumonia, mortality, unfavorable Glasgow Outcome Scale score, longer stay in the neuro-intensive care unit (ICU) and hospitalization, and higher hospitalization costs compared with successful extubation. CONCLUSIONS History of craniotomy, preoperative lower cranial nerve dysfunction, tumor size, tumor position, and maximum change in BP during the operation were independent risk factors related to postoperative failed extubation in patients submitted to infratentorial craniotomy. Extubation failure raises the incidences of postoperative pneumonia, mortality, and higher hospitalization costs, and prolongs neuro-ICU and postoperative length of stay.

  6. Can Machine Learning Methods Predict Extubation Outcome in Premature Infants as well as Clinicians?

    PubMed Central

    Mueller, Martina; Almeida, Jonas S.; Stanislaus, Romesh; Wagner, Carol L.

    2014-01-01

    Rationale Though treatment of the prematurely born infant breathing with assistance of a mechanical ventilator has much advanced in the past decades, predicting extubation outcome at a given point in time remains challenging. Numerous studies have been conducted to identify predictors for extubation outcome; however, the rate of infants failing extubation attempts has not declined. Objective To develop a decision-support tool for the prediction of extubation outcome in premature infants using a set of machine learning algorithms Methods A dataset assembled from 486 premature infants on mechanical ventilation was used to develop predictive models using machine learning algorithms such as artificial neural networks (ANN), support vector machine (SVM), naïve Bayesian classifier (NBC), boosted decision trees (BDT), and multivariable logistic regression (MLR). Performance of all models was evaluated using area under the curve (AUC). Results For some of the models (ANN, MLR and NBC) results were satisfactory (AUC: 0.63–0.76); however, two algorithms (SVM and BDT) showed poor performance with AUCs of ~0.5. Conclusion Clinician's predictions still outperform machine learning due to the complexity of the data and contextual information that may not be captured in clinical data used as input for the development of the machine learning algorithms. Inclusion of preprocessing steps in future studies may improve the performance of prediction models. PMID:25419493

  7. Prediction of extubation outcome: a randomised, controlled trial with automatic tube compensation vs. pressure support ventilation

    PubMed Central

    Cohen, Jonathan; Shapiro, Maury; Grozovski, Elad; Fox, Ben; Lev, Shaul; Singer, Pierre

    2009-01-01

    Introduction Tolerance of a spontaneous breathing trial is an evidence-based strategy to predict successful weaning from mechanical ventilation. Some patients may not tolerate the trial because of the respiratory load imposed by the endotracheal tube, so varying levels of respiratory support are widely used during the trial. Automatic tube compensation (ATC), specifically developed to overcome the imposed work of breathing because of artificial airways, appears ideally suited for the weaning process. We further evaluated the use of ATC in this setting. Methods In a prospective study, patients who had received mechanical ventilation for more than 24 hours and met defined criteria for a weaning trial, underwent a one-hour spontaneous breathing trial with either ATC (n = 87) or pressure support ventilation (PSV; n = 93). Those tolerating the trial were immediately extubated. The primary outcome measure was the ability to maintain spontaneous, unassisted breathing for more than 48 hours after extubation. In addition, we measured the frequency/tidal volume ratio (f/VT) both with (ATC-assisted) and without ATC (unassisted-f/VT) at the start of the breathing trial as a pretrial predictor of extubation outcome. Results There were no significant differences in any of the baseline characteristics between the two groups apart from a significantly higher Acute Physiology and Chronic Health Evaluation (APACHE) II score in the ATC group (p = 0.009). In the PSV group, 13 of 93 (14%) patients failed the breathing trial compared with only 6 of 87 (6%) in the ATC group; this observed 8% difference, however, did not reach statistical significance (p = 0.12). The rate of reintubation was not different between the groups (total group = 17.3%; ATC = 18.4% vs. PSV = 12.9%, p = 0.43). The percentage of patients who remained extubated for more than 48 hours was similar in both groups (ATC = 74.7% vs. PSV = 73.1%; p = 0.81). This represented a positive predictive value for PSV of 0.85 and

  8. Clinical prediction of weaning and extubation in Australian and New Zealand intensive care units.

    PubMed

    Rose, L; Presneill, J J

    2011-07-01

    Our objective was to describe, in Australian and New Zealand adult intensive care units, the relative frequency in which various clinical criteria were used to predict weaning and extubation, and the weaning methods employed. Participant intensivists at 55 intensive care units completed a self-administered questionnaire, using visual analogue scales (0 = not at all predictive, 10 = perfectly predictive, not used = null score) to record the perceived utility of 30 potential predictors. Survey response rate was 71% (164/230). Those variables thought most predictive of weaning readiness were respiratory rate (median score 8.0, interquartile range 7.0 to 8.6) effective cough (7.3, 5.9 to 8.2) and pressure support setting (7.2, 6.0 to 8.0). The most highly rated predictors of extubation success were effective cough (8.0, 7.0 to 9.0), respiratory rate (8.0, 7.0 to 8.5) and Glasgow Coma Score (7.9, 6.1 to 8.3). Variables perceived least predictive of weaning and extubation success were P0.1, Acute Physiological and Chronic Health Evaluation score II, mean arterial pressure, electrolytes and maximum inspiratory pressure (individual median scores < 5). Most popular clinical criteria were those perceived to have high predictive accuracy, both for weaning (respiratory rate 96%, pressure support setting 94% and Glasgow coma score 91%) and extubation readiness (respiratory rate 98%, effective cough 94% and Glasgow Coma Score 92%). Weaning mostly employed pressure support ventilation (55%), with less use of synchronised intermittent mandatory ventilation (32%) and spontaneous breathing trials (13%). Classic ventilatory performance predictors including respiratory rate and effective cough were reported to be of greater clinical utility than other more recently proposed measures.

  9. Lower Interbreath Interval Complexity Is Associated With Extubation Failure in Mechanically Ventilated Patients During Spontaneous Breathing Trials

    DTIC Science & Technology

    2010-06-01

    patient tolerated the SBT, then measurement of respiratory rate (RR), rapid shallow breathing index (RSBI), and negative inspiratory force ( NIF ) were...no deaths in either cohort during the study period. The characteristics of the two groups, along with RR, duration of IBI, NIF , and RSBI calculated... NIF , and RSBI did not differ between groups, and that all subjects who were extubated had weaning parameters predictive of success. To explore the

  10. Predictive Factors for Efficacy and Safety of Prophylactic Theophylline for Extubation in Infants with Apnea of Prematurity

    PubMed Central

    Orita, Yuji; Mitarai, Fumi; Ishitsuka, Yoichi; Irikura, Mitsuru; Shimodozono, Yoshihiro; Douchi, Tsutomu; Takeda, Yasuo; Irie, Tetsumi

    2016-01-01

    Purpose This study aimed to evaluate predictive factors involved in efficacy and safety in Japanese infants who received theophylline therapy to prevent apnea of prematurity (AOP) after weaning from mechanical ventilation. Methods We retrospectively reviewed the medical records of infants who were administered intravenous aminophylline (theophylline ethylenediamine) for AOP at the neonatal intensive care unit, Kagoshima University Hospital, Japan, between January 2009 and June 2013. Results A total of 100 infants were evaluated as two separate groups in terms of efficacy and safety of theophylline. Sixty-seven (67.0%) infants had effective theophylline therapy. Multivariate logistic regression analysis showed that gestational age at birth was significant, with an odds ratio of 0.59 (p < 0.001). Receiver operating characteristic analysis showed that the cut-off value was 31.1 weeks old for predicting the efficacy of theophylline (specificity, 66.7%; sensitivity, 86.6%; p < 0.001; area under the curve, 0.750; 95% confidence interval, 0.45–0.74). Adverse reactions were identified in 21 (21.0%) infants. Multivariate logistic regression analysis showed that the number of days of theophylline administration from birth was associated with an increased risk of adverse reactions after theophylline administration (p = 0.01). Conclusions Physicians need to be aware of the possibility that theophylline fails to produce therapeutic effects for extubation in infants aged less than 31.1 weeks old, and adverse reactions can easily develop when theophylline is administered soon after birth. PMID:27388444

  11. Data Driven Device Failure Prediction

    DTIC Science & Technology

    2016-09-15

    solution is to use statistical machine learning to predict failure. However, since failure is still a relatively rare event, obtaining labelled training...were successful in creating realistic failure conditions that are accurately identified by statistical learning models. iv Acknowledgments Nothing...Jordan v Table of Contents Page Abstract

  12. Detecting failure of climate predictions

    NASA Astrophysics Data System (ADS)

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-09-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  13. Detecting failure of climate predictions

    USGS Publications Warehouse

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-01-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty1, 2. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies3. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  14. All India Difficult Airway Association 2016 guidelines for the management of anticipated difficult extubation

    PubMed Central

    Kundra, Pankaj; Garg, Rakesh; Patwa, Apeksh; Ahmed, Syed Moied; Ramkumar, Venkateswaran; Shah, Amit; Divatia, Jigeeshu Vasishtha; Shetty, Sumalatha Radhakrishna; Raveendra, Ubaradka S; Doctor, Jeson R; Pawar, Dilip K; Singaravelu, Ramesh; Das, Sabyasachi; Myatra, Sheila Nainan

    2016-01-01

    Extubation has an important role in optimal patient recovery in the perioperative period. The All India Difficult Airway Association (AIDAA) reiterates that extubation is as important as intubation and requires proper planning. AIDAA has formulated an algorithm based on the current evidence, member survey and expert opinion to incorporate all patients of difficult extubation for a successful extubation. The algorithm is not designed for a routine extubation in a normal airway without any associated comorbidity. Extubation remains an elective procedure, and hence, patient assessment including concerns related to airway needs to be done and an extubation strategy must be planned before extubation. Extubation planning would broadly be dependent on preventing reflex responses (haemodynamic and cardiovascular), presence of difficult airway at initial airway management, delayed recovery after the surgical intervention or airway difficulty due to pre-existing diseases. At times, maintaining a patent airway may become difficult either due to direct handling during initial airway management or due to surgical intervention. This also mandates a careful planning before extubation to avoid extubation failure. Certain long-standing diseases such as goitre or presence of obesity and obstructive sleep apnoea may have increased chances of airway collapse. These patients require planned extubation strategies for extubation. This would avoid airway collapse leading to airway obstruction and its sequelae. AIDAA suggests that the extubation plan would be based on assessment of the airway. Patients requiring suppression of haemodynamic responses would require awake extubation with pharmacological attenuation or extubation under deep anaesthesia using supraglottic devices as bridge. Patients with difficult airway (before surgery or after surgical intervention) or delayed recovery or difficulty due to pre-existing diseases would require step-wise approach. Oxygen supplementation should

  15. Predicting Electronic Failure from Smoke

    SciTech Connect

    Tanaka, T.J.

    1999-01-15

    Smoke can cause electronic equipment to fail through increased leakage currents and shorts. Sandia National Laboratories is studying the increased leakage currents caused by smoke with varying characteristics. The objective is to develop models to predict the failure of electronic equipment exposed to smoke. This requires the collection of data on the conductivity of smoke and knowledge of critical electrical systems that control high-consequence operations. We have found that conductivity is a function of the type of fuel, how it is burned, and smoke density. Video recordings of highly biased dc circuits exposed in a test chamber show that during a fire, smoke is attracted to high voltages and can build fragile carbon bridges that conduct leakage currents. The movement of air breaks the bridges, so the conductivity decreases after the fire is extinguished and the test chamber is vented. During the fire, however, electronic equipment may not operate correctly, leading to problems for critical operations dependent on electronic control. The potential for electronic failure is highly dependent on the type of electrical circuit, and Sandia National Laboratories plans to include electrical circuit modeling in the failure models.

  16. Prediction of Failure at University--or Failure of Prediction?

    ERIC Educational Resources Information Center

    Nisbet, J.; Welsh, J.

    1976-01-01

    The validity of a procedure for identifying students at risk of failure on the basis of first term examination results was checked by following up 188 students at risk, from a total of 1902 in Aberdeen University Arts Faculty in session 1974-75. (Editor)

  17. Failure mode analysis to predict product reliability.

    NASA Technical Reports Server (NTRS)

    Zemanick, P. P.

    1972-01-01

    The failure mode analysis (FMA) is described as a design tool to predict and improve product reliability. The objectives of the failure mode analysis are presented as they influence component design, configuration selection, the product test program, the quality assurance plan, and engineering analysis priorities. The detailed mechanics of performing a failure mode analysis are discussed, including one suggested format. Some practical difficulties of implementation are indicated, drawn from experience with preparing FMAs on the nuclear rocket engine program.

  18. Managing tracheal extubation in infants with stridor and congenital neuraxial anomalies

    PubMed Central

    Saigal, Deepti; Ganjoo, Pragati; Sharma, Megha U.; Singh, Daljit

    2016-01-01

    Stridor is a serious complication of congenital neuraxial anomalies, which though, can get completely resolved with early neurosurgical correction of the anomaly. However, stridor relief may or may not be achieved soon after surgery. Persistent postoperative stridor can potentially cause extubation failure that may be difficult to handle in small children. There are no extubation guidelines for difficult pediatric airways as yet, and fewer appropriate airway-assist devices for routine use. Management of an infant with occipital encephalocele, hydrocephalus and bilateral abductor vocal cord palsy, who developed post-extubation respiratory distress due to stridor is discussed, together with the relevant tracheal extubation issues in such cases. PMID:28217159

  19. Uncertainties in container failure time predictions

    SciTech Connect

    Williford, R.E.

    1990-01-01

    Stochastic variations in the local chemical environment of a geologic waste repository can cause corresponding variations in container corrosion rates and failure times, and thus in radionuclide release rates. This paper addresses how well the future variations in repository chemistries must be known in order to predict container failure times that are bounded by a finite time period within the repository lifetime. Preliminary results indicate that a 5000 year scatter in predicted container failure times requires that repository chemistries be known to within {plus minus}10% over the repository lifetime. These are small uncertainties compared to current estimates. 9 refs., 3 figs.

  20. Prediction of Cascading Failures in Spatial Networks.

    PubMed

    Shunkun, Yang; Jiaquan, Zhang; Dan, Lu

    2016-01-01

    Cascading overload failures are widely found in large-scale parallel systems and remain a major threat to system reliability; therefore, they are of great concern to maintainers and managers of different systems. Accurate cascading failure prediction can provide useful information to help control networks. However, for a large, gradually growing network with increasing complexity, it is often impractical to explore the behavior of a single node from the perspective of failure propagation. Fortunately, overload failures that propagate through a network exhibit certain spatial-temporal correlations, which allows the study of a group of nodes that share common spatial and temporal characteristics. Therefore, in this study, we seek to predict the failure rates of nodes in a given group using machine-learning methods. We simulated overload failure propagations in a weighted lattice network that start with a center attack and predicted the failure percentages of different groups of nodes that are separated by a given distance. The experimental results of a feedforward neural network (FNN), a recurrent neural network (RNN) and support vector regression (SVR) all show that these different models can accurately predict the similar behavior of nodes in a given group during cascading overload propagation.

  1. Evaluating Risk Factors for Pediatric Post-extubation Upper Airway Obstruction Using a Physiology-based Tool

    PubMed Central

    Hotz, Justin; Morzov, Rica; Flink, Rutger; Kamerkar, Asavari; Ross, Patrick A.; Newth, Christopher J. L.

    2016-01-01

    Rationale: Subglottic edema is the most common cause of pediatric extubation failure, but few studies have confirmed risk factors or prevention strategies. This may be due to subjective assessment of stridor or inability to differentiate supraglottic from subglottic disease. Objectives: Objective 1 was to assess the utility of calibrated respiratory inductance plethysmography (RIP) and esophageal manometry to identify clinically significant post-extubation upper airway obstruction (UAO) and differentiate subglottic from supraglottic UAO. Objective 2 was to identify risk factors for subglottic UAO, stratified by cuffed versus uncuffed endotracheal tubes (ETTs). Methods: We conducted a single-center prospective study of children receiving mechanical ventilation. UAO was defined by inspiratory flow limitation (measured by RIP and esophageal manometry) and classified as subglottic or supraglottic based on airway maneuver response. Clinicians performed simultaneous blinded clinical UAO assessment at the bedside. Measurements and Main Results: A total of 409 children were included, 98 of whom had post-extubation UAO and 49 (12%) of whom were subglottic. The reintubation rate was 34 (8.3%) of 409, with 14 (41%) of these 34 attributable to subglottic UAO. Five minutes after extubation, RIP and esophageal manometry better identified patients who subsequently received UAO treatment than clinical UAO assessment (P < 0.006). Risk factors independently associated with subglottic UAO included low cuff leak volume or high preextubation leak pressure, poor sedation, and preexisting UAO (P < 0.04) for cuffed ETTs; and age (range, 1 mo to 5 yr) for uncuffed ETTs (P < 0.04). For uncuffed ETTs, the presence or absence of preextubation leak was not associated with subglottic UAO. Conclusions: RIP and esophageal manometry can objectively identify subglottic UAO after extubation. Using this technique, preextubation leak pressures or cuff leak volumes predict subglottic UAO in

  2. Extubation with or without spontaneous breathing trial.

    PubMed

    Wang, Jing; Ma, Yingmin; Fang, Qiuhong

    2013-12-01

    Purpose- To evaluate whether spontaneous breathing trials (SBTs) are necessary when extubating critical care patients. Methods- A prospective, randomized, double-blind study was performed in adult patients supported by mechanical ventilation for at least 48 hours in the general intensive care unit of a teaching hospital. Patients ready for weaning were randomly assigned to either the SBT group (extubation with an SBT) or the no-SBT group (extubation without an SBT). Patients in the SBT group who tolerated SBT underwent immediate extubation. Patients in the no-SBT group who met the weaning readiness criteria underwent extubation without an SBT. The primary outcome measure was a successful extubation or the ability to maintain spontaneous breathing for 48 hours after extubation. Results- A total of 139 adult patients were enrolled. No significant difference in the demographic, respiratory, and hemodynamic characteristics was indicated between the groups at the end of weaning readiness assessment. Successful extubation was achieved in 56 of 61 patients (91.8%) in the SBT group and 54 of 60 patients (90.0%) in the no-SBT group. In the SBT and no-SBT groups, 5 (8.2%) and 6 (10.0%) patients, respectively, needed reintubation; 7 (11.5%) and 9 (15.0%) patients, respectively, required noninvasive ventilation after extubation. In-hospital mortality did not differ significantly between the groups. Conclusion- Intensive care patients can be extubated successfully without an SBT.

  3. Methods, apparatus and system for notification of predictable memory failure

    DOEpatents

    Cher, Chen-Yong; Andrade Costa, Carlos H.; Park, Yoonho; Rosenburg, Bryan S.; Ryu, Kyung D.

    2017-01-03

    A method for providing notification of a predictable memory failure includes the steps of: obtaining information regarding at least one condition associated with a memory; calculating a memory failure probability as a function of the obtained information; calculating a failure probability threshold; and generating a signal when the memory failure probability exceeds the failure probability threshold, the signal being indicative of a predicted future memory failure.

  4. [Predictors of extubation failure in neurosurgical patients].

    PubMed

    León-Gutiérrez, Marco Antonio; Tanus-Hajj, Janet; Sánchez-Hurtado, Luis Alejandro

    2016-01-01

    Introducción: la información con respecto a los factores que afectan el éxito de la extubación en pacientes neuroquirúrgicos es limitada; por lo tanto, es necesario determinar los factores que inciden en esta condición. Métodos: estudio prospectivo, longitudinal, observacional y comparativo en pacientes neuroquirúrgicos con criterios para la extubación. En aquellos que presentaron fracaso se analizó el número de aspiraciones endotraqueales en las 24 horas previas a la extubación, la presencia del reflejo de tos, los días de estancia y de ventilación mecánica. Resultados: se incluyeron 70 pacientes en el estudio, de los cuales el 11.4 % presentó fracaso de la extubación y los factores asociados fueron la realización de 6 aspiraciones de secreciones endotraqueales 24 horas previas a la extubación (con una razón de riesgo [RR] = 1.88, intervalo de confianza [IC] al 95 % = 1.14-3.09, p 0.01), 7 días de ventilación mecánica (RR = 1.31, IC 95 % = 1.08-1.57, p 0.005) y 7.5 días de estancia (RR = 1.24, IC 95 % = 1.05-1.47, p 0.01). Conclusión: hacer seis o más aspiraciones de secreciones endotraqueales durante las 24 horas previas a la extubación es un factor de riesgo para el fracaso de la extubación de pacientes neuroquirúrgicos.

  5. Prediction for human motion tracking failures.

    PubMed

    Dockstader, Shiloh L; Imennov, Nikita S

    2006-02-01

    We propose a new and effective method of predicting tracking failures and apply it to the robust analysis of gait and human motion. We define a tracking failure as an event and describe its temporal characteristics using a hidden Markov model (HMM). We represent the human body using a three-dimensional, multicomponent structural model, where each component is designed to independently allow the extraction of certain gait variables. To enable a fault-tolerant tracking and feature extraction system, we introduce a single HMM for each element of the structural model, trained on previous examples of tracking failures. The algorithm derives vector observations for each Markov model using the time-varying noise covariance matrices of the structural model parameters. When transformed with a logarithmic function, the conditional output probability of each HMM is shown to have a causal relationship with imminent tracking failures. We demonstrate the effectiveness of the proposed approach on a variety of multiview video sequences of complex human motion.

  6. Progress in Predicting Rock-Slope Failures

    NASA Astrophysics Data System (ADS)

    Korup, O.

    2015-12-01

    Recent research on predicting landslides has seen a massive increase in statistical and computational methods that are largely adapted from the fields of machine learning and data mining. Judging from a sample of some 150 recent scientific papers, the gross majority of the reported success rates of these statistical methods are overwhelmingly high and promising at between 71% and 98%. Perhaps surprisingly, though, the death toll and damage from landslides has remained elevated in the early 21st century, so that reliably predicting the occurrence of rock-slope failures without overfitting our models remains challenging. Here I review some of the recent advances in this field, and show how novel results from landslide seismology and landslide sedimentology have promoted our ability of detecting large rock-slope failures in mountainous terrain. Several new detailed investigations of the internal nature of large rockslide deposits, for example, help to reduce the confusion potential with macroscopically similar moraine debris, or microscopically similar fault breccia. I further outline some of the limitations of empirical models that use rainfall intensity-duration thresholds for landslide early warning, and of multivariate methods concerned with mapping landslide susceptibility at the regional scale. I conclude by discussing the occurrence of 'black swans' such as long-runout rock-ice avalanches in size distributions of rock-slope failures, and their implications for quantitative hazard appraisals.

  7. Association between the rapid shallow breathing index and extubation success in patients with traumatic brain injury

    PubMed Central

    dos Reis, Helena França Correia; Almeida, Mônica Lajana Oliveira; da Silva, Mário Ferreira; Moreira, Julião Oliveira; Rocha, Mário de Seixas

    2013-01-01

    Objective To investigate the association between the rapid shallow breathing index and successful extubation in patients with traumatic brain injury. Methods This study was a prospective study conducted in patients with traumatic brain injury of both genders who underwent mechanical ventilation for at least two days and who passed a spontaneous breathing trial. The minute volume and respiratory rate were measured using a ventilometer, and the data were used to calculate the rapid shallow breathing index (respiratory rate/tidal volume). The dependent variable was the extubation outcome: reintubation after up to 48 hours (extubation failure) or not (extubation success). The independent variable was the rapid shallow breathing index measured after a successful spontaneous breathing trial. Results The sample comprised 119 individuals, including 111 (93.3%) males. The average age of the sample was 35.0±12.9 years old. The average duration of mechanical ventilation was 8.1±3.6 days. A total of 104 (87.4%) participants achieved successful extubation. No association was found between the rapid shallow breathing index and extubation success. Conclusion The rapid shallow breathing index was not associated with successful extubation in patients with traumatic brain injury. PMID:24213084

  8. Factors Influencing Progressive Failure Analysis Predictions for Laminated Composite Structure

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.

    2008-01-01

    Progressive failure material modeling methods used for structural analysis including failure initiation and material degradation are presented. Different failure initiation criteria and material degradation models are described that define progressive failure formulations. These progressive failure formulations are implemented in a user-defined material model for use with a nonlinear finite element analysis tool. The failure initiation criteria include the maximum stress criteria, maximum strain criteria, the Tsai-Wu failure polynomial, and the Hashin criteria. The material degradation model is based on the ply-discounting approach where the local material constitutive coefficients are degraded. Applications and extensions of the progressive failure analysis material model address two-dimensional plate and shell finite elements and three-dimensional solid finite elements. Implementation details are described in the present paper. Parametric studies for laminated composite structures are discussed to illustrate the features of the progressive failure modeling methods that have been implemented and to demonstrate their influence on progressive failure analysis predictions.

  9. Predicting Failure Progression and Failure Loads in Composite Open-Hole Tension Coupons

    NASA Technical Reports Server (NTRS)

    Arunkumar, Satyanarayana; Przekop, Adam

    2010-01-01

    Failure types and failure loads in carbon-epoxy [45n/90n/-45n/0n]ms laminate coupons with central circular holes subjected to tensile load are simulated using progressive failure analysis (PFA) methodology. The progressive failure methodology is implemented using VUMAT subroutine within the ABAQUS(TradeMark)/Explicit nonlinear finite element code. The degradation model adopted in the present PFA methodology uses an instantaneous complete stress reduction (COSTR) approach to simulate damage at a material point when failure occurs. In-plane modeling parameters such as element size and shape are held constant in the finite element models, irrespective of laminate thickness and hole size, to predict failure loads and failure progression. Comparison to published test data indicates that this methodology accurately simulates brittle, pull-out and delamination failure types. The sensitivity of the failure progression and the failure load to analytical loading rates and solvers precision is demonstrated.

  10. Failure strength prediction for adhesively bonded single lap joints

    NASA Astrophysics Data System (ADS)

    Rahman, Niat Mahmud

    For adhesively bonded joint, failure strength depends on many factors such as material properties (both adhesive and adherend), specimen geometries, test environments, surface preparation procedures, etc. Failure occurs inside constitutive materials or along joint interfaces. Based on location, adhesively bonded failure mode can be classified as adhesive failure mode, cohesive failure mode and adherend failure mode. Failure mode directly affects the failure strength of joint. For last eight decades, researchers have developed analytical, empirical or semi-empirical methods capable of predicting failure strength for adhesively bonded joints generating either cohesive failure or adherend failure. Applicability of most of the methods is limited to particular cases. In this research, different failure modes for single lap joints (SLJs) were generated experimentally using epoxy based paste adhesive. Based on experimental data and analytical study, simplified failure prediction methods were developed for each failure mode. For adhesive failure mode, it is observed that peel stress distributions concur along interface near crack initiation points. All SLJs for this test endured consistent surface treatments. Geometric parameters of the joints were varied to study their effect on failure strength. Peel stress distributions were calculated using finite analysis (FEA). Based on peel stress distribution near crack initiation point, a failure model is proposed. Numerous analytical, empirical and semi-empirical models are available for predicting failure strengths of SLJs generating cohesive failures. However, most of the methods in the literature failed to capture failure behavior of SLJs having thickness of adhesive layer as variable. Cohesive failure mode was generated experimentally using aluminum as adherend and epoxy adhesive considering thickness of adhesive layers as variable within SLJs. Comparative study was performed among various methods. It was observed that

  11. Predictability of steel containment response near failure

    SciTech Connect

    Costello, J.F.; Ludwigsen, J.S.; Luk, V.K.; Hessheimer, M.F.

    2000-01-06

    The Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission Office of Nuclear Regulatory Research, are co-sponsoring and jointly funding a Cooperative Containment Research Program at Sandia National Laboratories, Albuquerque, New Mexico, USA. As a part of this program, a steel containment vessel model and contact structure assembly was tested to failure with over pressurization at Sandia on December 11--12, 1996. The steel containment vessel model was a mixed-scale model (1:10 in geometry and 1:4 in shell thickness) of a steel containment for an improved Mark-II Boiling Water Reactor plant in Japan. The contact structure, which is a thick, bell-shaped steel shell separated at a nominally uniform distance from the model, provides a simplified representation of features of the concrete reactor shield building in the actual plant. The objective of the internal pressurization test was to provide measurement data of the structural response of the model up to its failure in order to validate analytical modeling, to find its pressure capacity, and to observe the failure model and mechanisms.

  12. Prediction of Technological Failures in Nuclear Power Plant Operation

    SciTech Connect

    Salnykov, A. A.

    2015-01-15

    A method for predicting operating technological failures in nuclear power plants which makes it possible to reduce the unloading of the generator unit during the onset and development of an anomalous engineering state of the equipment by detecting a change in state earlier and taking suitable measures. With the circulating water supply loop of a nuclear power plant as an example, scenarios and algorithms for predicting technological failures in the operation of equipment long before their actual occurrence are discussed.

  13. Computational Methods for Failure Analysis and Life Prediction

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler); Harris, Charles E. (Compiler); Housner, Jerrold M. (Compiler); Hopkins, Dale A. (Compiler)

    1993-01-01

    This conference publication contains the presentations and discussions from the joint UVA/NASA Workshop on Computational Methods for Failure Analysis and Life Prediction held at NASA Langley Research Center 14-15 Oct. 1992. The presentations focused on damage failure and life predictions of polymer-matrix composite structures. They covered some of the research activities at NASA Langley, NASA Lewis, Southwest Research Institute, industry, and universities. Both airframes and propulsion systems were considered.

  14. Reflex cough PEF as a predictor of successful extubation in neurological patients*

    PubMed Central

    Kutchak, Fernanda Machado; Debesaitys, Andressa Maciel; Rieder, Marcelo de Mello; Meneguzzi, Carla; Skueresky, Amanda Soares; Alberto, Luiz; Bianchin, Marino Muxfeldt

    2015-01-01

    Abstract Objective: To evaluate the use of reflex cough PEF as a predictor of successful extubation in neurological patients who were candidates for weaning from mechanical ventilation. Methods: This was a cross-sectional study of 135 patients receiving mechanical ventilation for more than 24 h in the ICU of Cristo Redentor Hospital, in the city of Porto Alegre, Brazil. Reflex cough PEF, the rapid shallow breathing index, MIP, and MEP were measured, as were ventilatory, hemodynamic, and clinical parameters. Results: The mean age of the patients was 47.8 ± 17 years. The extubation failure rate was 33.3%. A reflex cough PEF of < 80 L/min showed a relative risk of 3.6 (95% CI: 2.0-6.7), and the final Glasgow Coma Scale score showed a relative risk of 0.64 (95% CI: 0.51-0.83). For every 1-point increase in a Glasgow Coma Scale score of 8, there was a 36% reduction in the risk of extubation failure. Conclusions: Reflex cough PEF and the Glasgow Coma Scale score are independent predictors of extubation failure in neurological patients admitted to the ICU. PMID:26398756

  15. Two-parameter Failure Model Improves Time-independent and Time-dependent Failure Predictions

    SciTech Connect

    Huddleston, R L

    2004-01-27

    A new analytical model for predicting failure under a generalized, triaxial stress state was developed by the author and initially reported in 1984. The model was validated for predicting failure under elevated-temperature creep-rupture conditions. Biaxial data for three alloy steels, Types 304 and 316 stainless steels and Inconel 600, demonstrated two to three orders of magnitude reduction in the scatter of predicted versus observed creep-rupture times as compared to the classical failure models of Mises, Tresca, and Rankine. In 1990, the new model was incorporated into American Society of Mechanical Engineers (ASME) Code Case N47-29 for design of components operating under creep-rupture conditions. The current report provides additional validation of the model for predicting failure under time-independent conditions and also outlines a methodology for predicting failure under cyclic, time-dependent, creep-fatigue conditions. The later extension of the methodology may have the potential to improve failure predictions there as well. These results are relevant to most design applications, but they have special relevance to high-performance design applications such as components for high-pressure equipment, nuclear reactors, and jet engines.

  16. Successful Extubation Using Heliox BiPAP in Two Patients with Postextubation Stridor

    PubMed Central

    Punj, Pragya; Nattanmai, Premkumar; George, Pravin

    2017-01-01

    Postextubation stridor is associated with significant morbidity. It commonly results in extubation failure after established medical treatment fails, such as nebulized epinephrine and/or intravenous steroids. The role of heliox (i.e., combination of helium and oxygen) in managing patients with postextubation stridor has not been fully established. We report two cases of postextubation stridor successfully treated with heliox delivered with bilevel positive airway pressure (BiPAP) after failure of standard medical therapy. PMID:28373921

  17. Predicting Modes and Displacements of Seismic Rock Slope Failures

    NASA Astrophysics Data System (ADS)

    Gibson, M. D.; Wartman, J.; Keefer, D. K.; Maclaughlin, M.; Arnold, L.; Applegate, K. N.; Smith, S.; Adams, S.

    2013-12-01

    Seismically induced rock slope failures have resulted in billions of dollars of economic damage and enormous loss of life throughout the world. Accurate prediction of the triggering and run out of these failures is elusive for a variety of reasons, including knowledge of the physical modes of failure. Our research explores the potential failure modes of an idealized rigid rock block and expands the modes typically considered to include not only sliding but also toppling (pure forward rotation) and slumping (combined backward rotation and translation). The yield acceleration (or minimum inertial acceleration to cause block movement) for slumping, similar to toppling, is found to be lower than for pure translational sliding. These yield accelerations indicate the initial modes of rock block failure; however, they do not always predict the ultimate failure mode. To predict the final failure modes, the results of discrete element numerical analyses were compared to pseudo static yield acceleration to develop a seismic failure mode decision-making chart based on block geometry and interface friction. With regard to seismic displacement predictions, current simplified models predicting ultimate displacement of a mass under seismic conditions are limited to purely translating, sliding blocks (i.e. Newmark's sliding block method). Our modeling introduces additional simplified analyses to predict ultimate displacement in toppling and slumping modes as well. Important findings from these new methods are that the magnitude of seismically-induced displacement is dependent on the size of the block (or failure mass) and that as the yield acceleration decreases the seismically induced displacements increase. We plan to map these tools into analyses that evaluate rock slope systems with complex geology and geotechnical characteristics. It is envisioned that the decision chart, which predicts the initial and ultimate modes of failure based on block geometry and interface friction

  18. Product component genealogy modeling and field-failure prediction

    SciTech Connect

    King, Caleb; Hong, Yili; Meeker, William Q.

    2016-04-13

    Many industrial products consist of multiple components that are necessary for system operation. There is an abundance of literature on modeling the lifetime of such components through competing risks models. During the life-cycle of a product, it is common for there to be incremental design changes to improve reliability, to reduce costs, or due to changes in availability of certain part numbers. These changes can affect product reliability but are often ignored in system lifetime modeling. By incorporating this information about changes in part numbers over time (information that is readily available in most production databases), better accuracy can be achieved in predicting time to failure, thus yielding more accurate field-failure predictions. This paper presents methods for estimating parameters and predictions for this generational model and a comparison with existing methods through the use of simulation. Our results indicate that the generational model has important practical advantages and outperforms the existing methods in predicting field failures.

  19. Prediction failure of a wolf landscape model

    USGS Publications Warehouse

    Mech, L.D.

    2006-01-01

    I compared 101 wolf (Canis lupus) pack territories formed in Wisconsin during 1993-2004 to the logistic regression predictive model of Mladenoff et al. (1995, 1997, 1999). Of these, 60% were located in putative habitat suitabilities 50% remained unoccupied by known packs after 24 years of recolonization. This model was a poor predictor of wolf re-colonizing locations in Wisconsin, apparently because it failed to consider the adaptability of wolves. Such models should be used cautiously in wolf-management or restoration plans.

  20. Failure probability prediction of dielectric ceramics in multilayer capacitors

    SciTech Connect

    Wereszczak, A.A.; Breder, K.; Ferber, M.K.; Bridge, R.J.; Riester, L.; Kirkland, T.P.

    1998-11-01

    Dielectric ceramics in multilayer capacitors are subjected to manufacturing or service thermomechanical stresses which, if severe enough, will cause mechanical failure and perhaps subsequent loss of electrical function. Strength of monolithic ceramics is probabilistic in nature; however, probabilistic design of such electronic ceramic components generally has not been used by manufacturers and end-users of these components. To illustrate how probabilistic design may be utilized for small components, the present study demonstrates the applicability of an existing probabilistic life design computer code in the prediction of failure probability of a dielectric ceramic in an arbitrary multilayer capacitor. Issues involving the generation of representative strength and fatigue data for specimens at this small scale and the ultimate failure probability prediction of dielectric ceramics in multilayer capacitors are presented. Additionally, alternative means to generate a strength distribution as input for the probabilistic life design computer codes which are under consideration by the authors are discussed.

  1. Fracture mechanics parameters for failure prediction of composite resins.

    PubMed

    De Groot, R; Van Elst, H C; Peters, M C

    1988-06-01

    This study contains the first part of a research project in which the applicability of fracture mechanics parameters to predict failure of a restored tooth was investigated. Fracture mechanics parameters have been used in dental research before, but were restricted to comparative studies between various brands of composites. The critical values of the opening mode stress intensity factor (KI), its equivalents, the strain energy release rate (GI), and the J integral (JI), were measured with single-edge notched-bend (SENB) specimens of dental composite in a three-point bend test. The measured values of KIc for Silux (KIc = 0.99 +/- 0.03 MNm-3/2) and P-30 (KIc = 1.88 +/- 0.12 MNm-3/2), compared with values from the literature, show quantitative agreement. The J integral was computed by means of finite element analysis (FEA) on a two-dimensional model of the SENB specimens. The critical value of the J integral (measured with SENB specimens, notch depth-to-width ratio (a/W) = 1/2) was used to predict failure of specimens having an arbitrary geometry. In this study, failure was predicted for SENB specimens with notch depth-to-width ratio (a/W) = 1/4 and 3/4. The predicted deflection and load at failure correspond well with the measured deflection and load.

  2. Model-Biased, Data-Driven Adaptive Failure Prediction

    NASA Technical Reports Server (NTRS)

    Leen, Todd K.

    2004-01-01

    This final report, which contains a research summary and a viewgraph presentation, addresses clustering and data simulation techniques for failure prediction. The researchers applied their techniques to both helicopter gearbox anomaly detection and segmentation of Earth Observing System (EOS) satellite imagery.

  3. Failure prediction of thin beryllium sheets used in spacecraft structures

    NASA Astrophysics Data System (ADS)

    Roschke, Paul N.; Mascorro, Edward; Papados, Photios; Serna, Oscar R.

    1991-12-01

    The primary objective of this study is to develop a method for prediction of failure of thin beryllium sheets that undergo complex states of stress. Major components of the research include experimental evaluation of strength parameters for cross-rolled beryllium sheet, application of the Tsai-Wu failure criterion to plate bending problems, development of a high order failure criterion, application of the new criterion to a variety of structures, and incorporation of both failure criteria into a finite element code. A Tsai-Wu failure model for SR-200 sheet material is developed from available tensile data, experiments carried out by NASA on two circular plates, and compression and off-axis experiments performed in this study. The failure surface obtained from the resulting criterion forms an ellipsoid. By supplementing experimental data used in the the two-dimensional criterion and modifying previously suggested failure criteria, a multi-dimensional failure surface is proposed for thin beryllium structures. The new criterion for orthotropic material is represented by a failure surface in six-dimensional stress space. In order to determine coefficients of the governing equation, a number of uniaxial, biaxial, and triaxial experiments are required. Details of these experiments and a complementary ultrasonic investigation are described in detail. Finally, validity of the criterion and newly determined mechanical properties is established through experiments on structures composed of SR200 sheet material. These experiments include a plate-plug arrangement under a complex state of stress and a series of plates with an out-of-plane central point load. Both criteria have been incorporated into a general purpose finite element analysis code. Numerical simulation incrementally applied loads to a structural component that is being designed and checks each nodal point in the model for exceedance of a failure criterion. If stresses at all locations do not exceed the failure

  4. Failure prediction of thin beryllium sheets used in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Roschke, Paul N.; Mascorro, Edward; Papados, Photios; Serna, Oscar R.

    1991-01-01

    The primary objective of this study is to develop a method for prediction of failure of thin beryllium sheets that undergo complex states of stress. Major components of the research include experimental evaluation of strength parameters for cross-rolled beryllium sheet, application of the Tsai-Wu failure criterion to plate bending problems, development of a high order failure criterion, application of the new criterion to a variety of structures, and incorporation of both failure criteria into a finite element code. A Tsai-Wu failure model for SR-200 sheet material is developed from available tensile data, experiments carried out by NASA on two circular plates, and compression and off-axis experiments performed in this study. The failure surface obtained from the resulting criterion forms an ellipsoid. By supplementing experimental data used in the the two-dimensional criterion and modifying previously suggested failure criteria, a multi-dimensional failure surface is proposed for thin beryllium structures. The new criterion for orthotropic material is represented by a failure surface in six-dimensional stress space. In order to determine coefficients of the governing equation, a number of uniaxial, biaxial, and triaxial experiments are required. Details of these experiments and a complementary ultrasonic investigation are described in detail. Finally, validity of the criterion and newly determined mechanical properties is established through experiments on structures composed of SR200 sheet material. These experiments include a plate-plug arrangement under a complex state of stress and a series of plates with an out-of-plane central point load. Both criteria have been incorporated into a general purpose finite element analysis code. Numerical simulation incrementally applied loads to a structural component that is being designed and checks each nodal point in the model for exceedance of a failure criterion. If stresses at all locations do not exceed the failure

  5. Predicting the failure load of the distal radius.

    PubMed

    Muller, Monique E; Webber, Colin E; Bouxsein, Mary L

    2003-06-01

    The distal radius is an important site for the early detection of patients at risk for fracture. Since measuring bone strength in vivo is not possible, we evaluated which bone assessment method of the forearm would best predict failure load of the distal radius and computed a factor of risk for wrist fracture (Phi wrist). Thirty-eight cadaveric forearm specimens were measured by five different techniques to assess bone density, bone mineral content, geometry and trabecular structure at the distal forearm. The bone assessment techniques included dual-energy X-ray absorptiometry (DXA) of the radius, peripheral quantitative computed tomography (pQCT) of the 4% and 20% distal sites of the radius, DXA of the phalanges, digital X-ray radiogrammetry of the forearm (DXR-BMD), and quantitative ultrasound of the radius. The failure load of each excised radius was determined by simulating a fall on an outstretched hand. The pQCT measurements of polar stress-strain index and cortical content explained the greatest portion of variance in failure load (r2=0.82-0.85). Bone mineral content measures were generally better predictors of failure load (r2=0.53-0.85) than the corresponding volumetric or areal bone mineral density values (r2=0.22-0.69) measured by either pQCT or DXA. Multiple regression analysis showed that the addition of a bone geometry measure improved the ability of a bone density measure alone to predict failure load. There was high variability in the ability of different techniques and different variables within a given technique to predict failure load. Estimates of the factor of risk for wrist fracture (Phi wrist) revealed that the women in this study would have been likely to fracture their distal radius upon falling from a standing height (Phi wrist= 1.04), whereas the men would have likely withstood the impact without fracturing their wrist (Phi wrist= 0.79).

  6. Failure prediction of thin beryllium sheets used in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Roschke, Paul N.; Papados, Photios; Mascorro, Edward

    1991-01-01

    In an attempt to predict failure for cross-rolled beryllium sheet structures, high order macroscopic failure criteria are used. These require the knowledge of in-plane uniaxial and shear strengths. Test results are included for in-plane biaxial tension, uniaxial compression for two different material orientations, and shear. All beryllium specimens have the same chemical composition. In addition, all experimental work was performed in a controlled laboratory environment. Numerical simulation complements these tests. A brief bibliography supplements references listed in a previous report.

  7. Product component genealogy modeling and field-failure prediction

    DOE PAGES

    King, Caleb; Hong, Yili; Meeker, William Q.

    2016-04-13

    Many industrial products consist of multiple components that are necessary for system operation. There is an abundance of literature on modeling the lifetime of such components through competing risks models. During the life-cycle of a product, it is common for there to be incremental design changes to improve reliability, to reduce costs, or due to changes in availability of certain part numbers. These changes can affect product reliability but are often ignored in system lifetime modeling. By incorporating this information about changes in part numbers over time (information that is readily available in most production databases), better accuracy can bemore » achieved in predicting time to failure, thus yielding more accurate field-failure predictions. This paper presents methods for estimating parameters and predictions for this generational model and a comparison with existing methods through the use of simulation. Our results indicate that the generational model has important practical advantages and outperforms the existing methods in predicting field failures.« less

  8. Progressive Failure And Life Prediction of Ceramic and Textile Composites

    NASA Technical Reports Server (NTRS)

    Xue, David Y.; Shi, Yucheng; Katikala, Madhu; Johnston, William M., Jr.; Card, Michael F.

    1998-01-01

    An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions. Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. Comparisons were made with Graphite-Epoxy, C/SiC and Nicalon/CAS composite materials. For textile materials, comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension. Fatigue predictions were compared with test data obtained from plain weave C/SiC materials tested at AS&M. Computer codes were developed to perform the analysis. Composite Progressive Failure Analysis for Laminates is contained in the code CPFail. Micromechanics Analysis for Textile Composites is contained in the code MicroTex. Both codes were adapted to run as subroutines for the finite element code ABAQUS and CPFail-ABAQUS and MicroTex-ABAQUS. Graphic user interface (GUI) was developed to connect CPFail and MicroTex with ABAQUS.

  9. Relational Neural Evolution Approach to Bank Failure Prediction

    SciTech Connect

    Abudu, Bolanle; Markose, Sheri

    2007-12-26

    Relational neural networks as a concept offers a unique opportunity for improving classification accuracy by exploiting relational structure in data. The premise is that a relational classification technique, which uses information implicit in relationships, should classify more accurately than techniques that only examine objects in isolation. In this paper, we study the use of relational neural networks for predicting bank failure. Alongside classical financial ratios normally used as predictor variables, we introduced new relational variables for the network. The relational neural network structure, specified as a combination of feed forward and recurrent neural networks, is determined by bank data through neuro-evolution. We discuss empirical results comparing performance of the relational approach to standard propositional methods used for bank failure prediction.

  10. Relational Neural Evolution Approach to Bank Failure Prediction

    NASA Astrophysics Data System (ADS)

    Abudu, Bolanle; Markose, Sheri

    2007-12-01

    Relational neural networks as a concept offers a unique opportunity for improving classification accuracy by exploiting relational structure in data. The premise is that a relational classification technique, which uses information implicit in relationships, should classify more accurately than techniques that only examine objects in isolation. In this paper, we study the use of relational neural networks for predicting bank failure. Alongside classical financial ratios normally used as predictor variables, we introduced new relational variables for the network. The relational neural network structure, specified as a combination of feed forward and recurrent neural networks, is determined by bank data through neuro-evolution. We discuss empirical results comparing performance of the relational approach to standard propositional methods used for bank failure prediction.

  11. Predictive influence in the accelerated failure time model.

    PubMed

    Bedrick, Edward J; Exuzides, Alex; Johnson, Wesley O; Thurmond, Mark C

    2002-09-01

    We develop case deletion diagnostics for prediction of future observations in the accelerated failure time model. We view prediction to be an important inferential goal in a survival analysis and thus it is important to identify whether particular observations may be influencing the quality of predictions. We use the Kullback-Leibler divergence as a measure of the discrepancy between the estimated probability distributions for the full and the case-deleted samples. In particular, we focus on the effect of case deletion on estimated survival curves but where we regard the survival curve estimate as a vehicle for prediction. We also develop a diagnostic for assessing the effect of case deletion on inferences for the median time to failure. The estimated median can be used with both predictive and estimative purposes in mind. We also discuss the relationship between our suggested measures and the corresponding Cook distance measure, which was designed with the goal of assessing estimative influence. Several applications of the proposed diagnostics are presented.

  12. What is the optimal rate of failed extubation?

    PubMed Central

    2012-01-01

    Failed extubation (FE), defined as reintubation 48 or 72 hours after planned extubation, occurs in a significant percentage of patients and is associated with a substantial burden of morbidity and mortality. This commentary reviews the literature describing FE rates and the clinical consequences of FE and proposes an 'optimal' rate of FE as well as avenues for future research. PMID:22356725

  13. Out-of-bed extubation: a feasibility study

    PubMed Central

    Dexheimer Neto, Felippe Leopoldo; Vesz, Patrini Silveira; Cremonese, Rafael Viegas; Leães, Clarissa Garcia Soares; Raupp, Ana Carolina Tabajara; Rodrigues, Cristiano dos Santos; de Andrade, Juliana Mara Stormovski; Townsend, Raquel da Silva; Maccari, Juçara Gasparetto; Teixeira, Cassiano

    2014-01-01

    Objective In clinical intensive care practice, weaning from mechanical ventilation is accompanied by concurrent early patient mobilization. The aim of this study was to compare the success of extubation performed with patients seated in an armchair compared to extubation with patients in a supine position. Methods A retrospective study, observational and non-randomized was conducted in a mixed-gender, 23-bed intensive care unit. The primary study outcome was success of extubation, which was defined as the patient tolerating the removal of the endotracheal tube for at least 48 hours. The differences between the study groups were assessed using Student's t-test and chi-squared analysis. Results Ninety-one patients were included from December 2010 and June 2011. The study population had a mean age of 71 years ± 12 months, a mean APACHE II score of 21±7.6, and a mean length of mechanical ventilation of 2.6±2 days. Extubation was performed in 33 patients who were seated in an armchair (36%) and in 58 patients in a supine position (64%). There were no significant differences in age, mean APACHE II score or length of mechanical ventilation between the two groups, and a similar extubation success rate was observed (82%, seated group versus 85%, supine group, p>0.05). Furthermore, no significant differences were found between the two groups in terms of post-extubation distress, need for tracheostomy, duration of mechanical ventilation weaning, or intensive care unit stay. Conclusion Our results suggest that the clinical outcomes of patients extubated in a seated position are similar to those of patients extubated in a supine position. This new practice of seated extubation was not associated with adverse events and allowed extubation to occur simultaneously with early mobilization. PMID:25295820

  14. HDL Cholesterol Efflux Predicts Graft Failure in Renal Transplant Recipients

    PubMed Central

    Annema, Wijtske; Dikkers, Arne; Freark de Boer, Jan; Dullaart, Robin P. F.; Sanders, Jan-Stephan F.; Bakker, Stephan J. L.

    2016-01-01

    High-density lipoprotein (HDL) particles are involved in the protection against cardiovascular disease by promoting cholesterol efflux, in which accumulated cholesterol is removed from macrophage foam cells. We investigated whether HDL cholesterol efflux capacity is associated with cardiovascular mortality, all-cause mortality, and graft failure in a cohort of renal transplant recipients (n=495, median follow-up 7.0 years). Cholesterol efflux capacity at baseline was quantified using incubation of human macrophage foam cells with apolipoprotein B–depleted plasma. Baseline efflux capacity was not different in deceased patients and survivors (P=0.60 or P=0.50 for cardiovascular or all-cause mortality, respectively), whereas recipients developing graft failure had lower efflux capacity than those with functioning grafts (P<0.001). Kaplan–Meier analysis demonstrated a lower risk for graft failure (P=0.004) but not cardiovascular (P=0.30) or all-cause mortality (P=0.31) with increasing gender-stratified tertiles of efflux capacity. Cox regression analyses adjusted for age and gender showed that efflux capacity was not associated with cardiovascular mortality (hazard ratio [HR], 0.89; 95% confidence interval [95% CI], 0.67 to 1.19; P=0.43). Furthermore, the association between efflux capacity and all-cause mortality (HR, .79; 95% CI, 0.63 to 0.98; P=0.031) disappeared after further adjustment for potential confounders. However, efflux capacity at baseline significantly predicted graft failure (HR, 0.43; 95% CI, 0.29 to 0.64; P<0.001) independent of apolipoprotein A-I, HDL cholesterol, or creatinine clearance. In conclusion, this prospective study shows that cholesterol efflux capacity from macrophage foam cells is not associated with cardiovascular or all-cause mortality but is a strong predictor of graft failure independent of plasma HDL cholesterol levels in renal transplant recipients. PMID:26319244

  15. Prediction of long-term failure in Kevlar 49 composites

    SciTech Connect

    Gerstle, F.P. Jr.

    1982-01-01

    Creep rupture data in Kevlar 49 epoxy usually exhibit considerable scatter: the coefficient of variation (CV) about the mean failure time at a given stress exceeds 100%. Quasi-static strength data, in contrast, shows little scatter: <4% CV for pressure vessels and <10% for impregnated strands. In this paper analysis of existing creep rupture data on Kevlar epoxy vessels at four storage pressures has produced an interesting and useful result. It was found that a significant portion of the scatter in failure times for pressure vessels is due to spool-to-spool variation in the eight spools of Kevlar fibers used to wind the vessels. The order rank of mean times to failure was consistent over a pressure range from 3400 to 4300 psi, 68 to 86% of short term burst. Also, the coefficient of variation about the mean failure time for each spool was less than that for the total sample. The statistical inference that the sample is nonhomogeneous was supported by a nonparametric check using the Kruskal-Wallis test, and by a parametric analysis of variance. The order rank found in long-term tests did not unequivocally agree with static strength ranks; several spool sets were distinctly high or low. The implication is that, while static strengths are not valid predictors of long-term behavior, short term creep rupture tests at high stress definitely are. The material difference which causes the spool-to-spool variations has not yet been identified for all eight spools. However, it appears that Kevlar behavior at lower pressures may be predicted through the use of curves fitted to the data for each spool. A power law relating failure time to pressure, t = t/sub 0/(p/p/sub 0/)/sup m/, was found to fit the data reasonably well. The implication is that, both in composite vessel design and in creep rupture experiments, the pressure (or stress) level be carefully controlled.

  16. Rational temporal predictions can underlie apparent failures to delay gratification

    PubMed Central

    McGuire, Joseph T.; Kable, Joseph W.

    2013-01-01

    An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences and veridical judgments. Our account recognizes that decision makers generally face uncertainty regarding the time at which future outcomes will materialize. When timing is uncertain, the value of persistence depends crucially on the nature of a decision-maker’s prior temporal beliefs. Certain forms of temporal beliefs imply that a delay’s predicted remaining length increases as a function of time already waited. In this type of situation, the rational, utility-maximizing strategy is to persist for a limited amount of time and then give up. We show empirically that people’s explicit predictions of remaining delay lengths indeed increase as a function of elapsed time in several relevant domains, implying that temporal judgments offer a rational basis for limiting persistence. We then develop our framework into a simple working model and show how it accounts for individual differences in a laboratory task (the well-known “marshmallow test”). We conclude that delay-of-gratification failure, generally viewed as a manifestation of limited self-control capacity, can instead arise as an adaptive response to the perceived statistics of one’s environment. PMID:23458085

  17. Use of Biomarkers to Predict Readmission for Congestive Heart Failure.

    PubMed

    Sudharshan, Sangita; Novak, Eric; Hock, Karl; Scott, Mitchell G; Geltman, Edward M

    2017-02-01

    Acute decompensated heart failure (ADHF) is a major reason for repeated hospitalizations. Identifying those patients with ADHF at risk for readmission is critical so that preventive interventions can be implemented. Biomarkers such as B-type natriuretic peptide (BNP), high-sensitivity troponin I, and galectin-3 (Gal-3) assessed at discharge may be useful, although their role in predicting short-term readmission is not well defined in the literature. We enrolled and had follow-up data for 101 participants admitted to our facility from April 2013 to March 2015 with a primary diagnosis of ADHF. Gal-3, high-sensitivity troponin I, and BNP were obtained within 48 hours before hospital discharge after management of ADHF. Gal-3 was assessed using 2 commercially available assays. We compared subjects who were and were not readmitted. Discharge BNP was found to be a significant predictor of 30- and 60-day readmission (area under the curve [AUC] 0.69 [p = 0.046], AUC 0.7 [p = 0.005], respectively). The addition of Gal-3 to discharge BNP provided significantly improved prediction of 60-day readmission. Gal-3 alone was found to be a significant predictor of 60-day readmission in patients with preserved ejection fraction (AUC 0.85, p <0.001). The net reclassification improvement was 55.2 (p = 0.037). Using multivariate analysis, for every 100 pg/L BNP increase, the probability of readmission increased by approximately 10%, and for every 1-ng/ml Gal-3 increase, the probability further increased 8%. A statistically significant net reclassification improvement was not found on examination of 30-day readmission. In conclusion, measurement of both Gal-3 and BNP at hospital discharge provides significant prediction of hospital readmission within 60 days. When combined, the prediction of readmission is significantly improved.

  18. A mixture Weibull proportional hazard model for mechanical system failure prediction utilising lifetime and monitoring data

    NASA Astrophysics Data System (ADS)

    Zhang, Qing; Hua, Cheng; Xu, Guanghua

    2014-02-01

    As mechanical systems increase in complexity, it is becoming more and more common to observe multiple failure modes. The system failure can be regarded as the result of interaction and competition between different failure modes. It is therefore necessary to combine multiple failure modes when analysing the failure of an overall system. In this paper, a mixture Weibull proportional hazard model (MWPHM) is proposed to predict the failure of a mechanical system with multiple failure modes. The mixed model parameters are estimated by combining historical lifetime and monitoring data of all failure modes. In addition, the system failure probability density is obtained by proportionally mixing the failure probability density of multiple failure modes. Monitoring data are input into the MWPHM to estimate the system reliability and predict the system failure time. A simulated sample set is used to verify the ability of the MWPHM to model multiple failure modes. Finally, the MWPHM and the traditional Weibull proportional hazard model (WPHM) are applied to a high-pressure water descaling pump, which has two failure modes: sealing ring wear and thrust bearing damage. Results show that the MWPHM is greatly superior in system failure prediction to the WPHM.

  19. Flood Water Level Mapping and Prediction Due to Dam Failures

    NASA Astrophysics Data System (ADS)

    Musa, S.; Adnan, M. S.; Ahmad, N. A.; Ayob, S.

    2016-07-01

    Sembrong dam has undergone overflow failure. Flooding has been reported to hit the town, covering an area of up to Parit Raja, located in the district of Batu Pahat. This study aims to identify the areas that will be affected by flood in the event of a dam failure in Sembrong Dam, Kluang, Johor at a maximum level. To grasp the extent, the flood inundation maps have been generated by using the InfoWorks ICM and GIS software. By using these maps, information such as the depth and extent of floods can be identified the main ares flooded. The flood map was created starting with the collection of relevant data such as measuring the depth of the river and a maximum flow rate for Sembrong Dam. The data were obtained from the Drainage and Irrigation Department Malaysia and the Department of Survey and Mapping and HLA Associates Sdn. Bhd. Then, the data were analyzed according to the established Info Works ICM method. The results found that the flooded area were listed at Sri Lalang, Parit Sagil, Parit Sonto, Sri Paya, Parit Raja, Parit Sempadan, Talang Bunut, Asam Bubok, Tanjung Sembrong, Sungai Rambut and Parit Haji Talib. Flood depth obtained for the related area started from 0.5 m up to 1.2 m. As a conclusion, the flood emanating from this study include the area around the town of Ayer Hitam up to Parit Raja approximately of more than 20 km distance. This may give bad implication to residents around these areas. In future studies, other rivers such as Sungai Batu Pahat should be considered for this study to predict and reduce the yearly flood victims for this area.

  20. Factors influencing the predictive power of models for predicting mortality and/or heart failure hospitalization in patients with heart failure.

    PubMed

    Ouwerkerk, Wouter; Voors, Adriaan A; Zwinderman, Aeilko H

    2014-10-01

    The present paper systematically reviews and compares existing prediction models in order to establish the strongest variables, models, and model characteristics in patients with heart failure predicting outcome. To improve decision making accurately predicting mortality and heart-failure hospitalization in patients with heart failure can be important for selecting patients with a poorer prognosis or nonresponders to current therapy, to improve decision making. MEDLINE/PubMed was searched for papers dealing with heart failure prediction models. To identify similar models on the basis of their variables hierarchical cluster analysis was performed. Meta-analysis was used to estimate the mean predictive value of the variables and models; meta-regression was used to find characteristics that explain variation in discriminating values between models. We identified 117 models in 55 papers. These models used 249 different variables. The strongest predictors were blood urea nitrogen and sodium. Four subgroups of models were identified. Mortality was most accurately predicted by prospective registry-type studies using a large number of clinical predictor variables. Mean C-statistic of all models was 0.66 ± 0.0005, with 0.71 ± 0.001, 0.68 ± 0.001 and 0.63 ± 0.001 for models predicting mortality, heart failure hospitalization, or both, respectively. There was no significant difference in discriminating value of models between patients with chronic and acute heart failure. Prediction of mortality and in particular heart failure hospitalization in patients with heart failure remains only moderately successful. The strongest predictors were blood urea nitrogen and sodium. The highest C-statistic values were achieved in a clinical setting, predicting short-term mortality with the use of models derived from prospective cohort/registry studies with a large number of predictor variables.

  1. Predicting oligonucleotide-directed mutagenesis failures in protein engineering

    PubMed Central

    Wassman, Christopher D.; Tam, Phillip Y.; Lathrop, Richard H.; Weiss, Gregory A.

    2004-01-01

    Protein engineering uses oligonucleotide-directed mutagenesis to modify DNA sequences through a two-step process of hybridization and enzymatic synthesis. Inefficient reactions confound attempts to introduce mutations, especially for the construction of vast combinatorial protein libraries. This paper applied computational approaches to the problem of inefficient mutagenesis. Several results implicated oligonucleotide annealing to non-target sites, termed ‘cross-hybridization’, as a significant contributor to mutagenesis reaction failures. Test oligonucleotides demonstrated control over reaction outcomes. A novel cross-hybridization score, quickly computable for any plasmid and oligonucleotide mixture, directly correlated with yields of deleterious mutagenesis side products. Cross-hybridization was confirmed conclusively by partial incorporation of an oligonucleotide at a predicted cross-hybridization site, and by modification of putative template secondary structure to control cross-hybridization. Even in low concentrations, cross-hybridizing species in mixtures poisoned reactions. These results provide a basis for improved mutagenesis efficiencies and increased diversities of cognate protein libraries. PMID:15585664

  2. Residual paralysis at the time of tracheal extubation.

    PubMed

    Murphy, Glenn S; Szokol, Joseph W; Marymont, Jesse H; Franklin, Mark; Avram, Michael J; Vender, Jeffery S

    2005-06-01

    Respiratory and pharyngeal muscle function are impaired during minimal neuromuscular blockade. Tracheal extubation in the presence of residual paresis may contribute to adverse respiratory events. In this investigation, we assessed the incidence and severity of residual neuromuscular block at the time of tracheal extubation. One-hundred-twenty patients presenting for gynecologic or general surgical procedures were enrolled. Neuromuscular blockade was maintained with rocuronium (visual train-of-four [TOF] count of 2) and all subjects were reversed with neostigmine at a TOF count of 2-4. TOF ratios were quantified using acceleromyography immediately before tracheal extubation, after clinicians had determined that complete neuromuscular recovery had occurred using standard clinical criteria (5-s head lift or hand grip, eye opening on command, acceptable negative inspiratory force or vital capacity breath values) and peripheral nerve stimulation (no evidence of fade with TOF or tetanic stimulation). TOF ratios were measured again on arrival to the postanesthesia care unit. Immediately before tracheal extubation, the mean TOF ratio was 0.67 +/- 0.2; among the 120 patients, 70 (58%) had a TOF ratio <0.7 and 105 (88%) had a TOF ratio <0.9. Significantly fewer patients had TOF ratios <0.7 (9 subjects, 8%) and <0.9 (38 subjects, 32%) in the postanesthesia care unit compared with the operating room (P < 0.001). Our results suggest that complete recovery from neuromuscular blockade is rarely present at the time of tracheal extubation.

  3. Sedation with a remifentanil infusion to facilitate rapid awakening and tracheal extubation in an infant with a potentially compromised airway

    PubMed Central

    Naples, Jeffrey; Hall, Mark W; Tobias, Joseph D

    2016-01-01

    Sedation is generally required during endotracheal intubation and mechanical ventilation in infants and children. While there are many options for the provision of sedation, the most commonly used agents such as midazolam and fentanyl demonstrate a context-sensitive half-life, which may result in a prolonged effect when these agents are discontinued following a continuous infusion. We present a 20-month-old infant who required endotracheal intubation due to respiratory failure following seizures. At the referring hospital, multiple laryngoscopies were performed with the potential for airway trauma. To maximize rapid awakening and optimize respiratory function surrounding tracheal extubation, sedation was transitioned from fentanyl and midazolam to remifentanil for 18–24 hours prior to tracheal extubation. The unique pharmacokinetics of remifentanil are presented in this study, its use in this clinical scenario is discussed, and its potential applications in the pediatric intensive care unit setting are reviewed. PMID:27826208

  4. Predictive Surgical Reasons for Failure After Coracoid Process Transfers

    PubMed Central

    Gasbarro, Gregory; Giugale, Juan Marcelo; Walch, Gilles; Lin, Albert

    2016-01-01

    Background: Recurrent anterior shoulder instability after coracoid process transfers may be caused by trauma, sports injury, or technical failure of the index procedure. Surgical techniques vary with regard to graft orientation and positioning and number of screws utilized for fixation. Purpose: To identify surgical and patient-related factors associated with failure, defined as the need for revision surgery. We hypothesized that failures will occur more commonly with single-screw fixation and graft malposition. Study Design: Case series; Level of evidence, 4. Methods: Eighty-three patients (mean age, 24 years) who underwent an Eden-Hybinette operation as a revision procedure for recurrent anterior instability after primary coracoid process transfer between 1977 and 2010 were retrospectively reviewed. Preoperative medical records were queried for demographic data, failure event, and physical examination. Two fellowship-trained shoulder surgeons reviewed radiographs to identify for graft positioning, nonunion, and hardware failure. Descriptive analysis was used to assess reasons for failure. Results: Seventy-five percent of patients sustained a redislocation event after primary coracoid process transfer. Revisions were performed on average 50.3 months after the index procedure, most commonly on males, with two-thirds of recurrent instability occurring during sports. Among all patients, single-screw methods for fixation and inferior graft malposition during index bone block transfer were the most common. Hardware failure and graft nonunion were more frequent with the single-screw technique. Conclusion: In our series, recurrent anterior shoulder instability after primary coracoid process transfer was more likely to occur during sports in young, male patients. The most common technical errors leading to revision were placing the graft inferior to the 5-o’clock position on the glenoid face or relying on single-screw fixation. PMID:28210649

  5. Predicting failure: acoustic emission of berlinite under compression.

    PubMed

    Nataf, Guillaume F; Castillo-Villa, Pedro O; Sellappan, Pathikumar; Kriven, Waltraud M; Vives, Eduard; Planes, Antoni; Salje, Ekhard K H

    2014-07-09

    Acoustic emission has been measured and statistical characteristics analyzed during the stress-induced collapse of porous berlinite, AlPO4, containing up to 50 vol% porosity. Stress collapse occurs in a series of individual events (avalanches), and each avalanche leads to a jerk in sample compression with corresponding acoustic emission (AE) signals. The distribution of AE avalanche energies can be approximately described by a power law p(E)dE = E(-ε)dE (ε ~ 1.8) over a large stress interval. We observed several collapse mechanisms whereby less porous minerals show the superposition of independent jerks, which were not related to the major collapse at the failure stress. In highly porous berlinite (40% and 50%) an increase of energy emission occurred near the failure point. In contrast, the less porous samples did not show such an increase in energy emission. Instead, in the near vicinity of the main failure point they showed a reduction in the energy exponent to ~ 1.4, which is consistent with the value reported for compressed porous systems displaying critical behavior. This suggests that a critical avalanche regime with a lack of precursor events occurs. In this case, all preceding large events were 'false alarms' and unrelated to the main failure event. Our results identify a method to use pico-seismicity detection of foreshocks to warn of mine collapse before the main failure (the collapse) occurs, which can be applied to highly porous materials only.

  6. Effect of various approximations on predicted progressive failure in plain weave composites

    NASA Technical Reports Server (NTRS)

    Whitcomb, John; Srirengan, Kanthikannan

    1995-01-01

    Three-dimensional finite element analysis was used to simulate progressive failure of a plain weave composite subjected to in-plane extension. The loading was parallel to one of the tow directions. The effects of various characteristics of the finite element model on predicted behavior were examined. The predicted behavior was found to be sensitive to quadrature order, mesh refinement, and the material degradation model. Also the sensitivity of the predictions to the tow waviness was studied. The predicted strength decreased considerably with increased waviness. More numerical studies and comparisons with experimental data are needed to establish reliable guidelines for accurate progressive failure prediction.

  7. Predicting Time Series Outputs and Time-to-Failure for an Aircraft Controller Using Bayesian Modeling

    NASA Technical Reports Server (NTRS)

    He, Yuning

    2015-01-01

    Safety of unmanned aerial systems (UAS) is paramount, but the large number of dynamically changing controller parameters makes it hard to determine if the system is currently stable, and the time before loss of control if not. We propose a hierarchical statistical model using Treed Gaussian Processes to predict (i) whether a flight will be stable (success) or become unstable (failure), (ii) the time-to-failure if unstable, and (iii) time series outputs for flight variables. We first classify the current flight input into success or failure types, and then use separate models for each class to predict the time-to-failure and time series outputs. As different inputs may cause failures at different times, we have to model variable length output curves. We use a basis representation for curves and learn the mappings from input to basis coefficients. We demonstrate the effectiveness of our prediction methods on a NASA neuro-adaptive flight control system.

  8. Method of Testing and Predicting Failures of Electronic Mechanical Systems

    NASA Technical Reports Server (NTRS)

    Iverson, David L.; Patterson-Hine, Frances A.

    1996-01-01

    A method employing a knowledge base of human expertise comprising a reliability model analysis implemented for diagnostic routines is disclosed. The reliability analysis comprises digraph models that determine target events created by hardware failures human actions, and other factors affecting the system operation. The reliability analysis contains a wealth of human expertise information that is used to build automatic diagnostic routines and which provides a knowledge base that can be used to solve other artificial intelligence problems.

  9. Experiences of patients with abnormal extubation of PICC tubes: a qualitative study

    PubMed Central

    Gao, Wei; Luan, Xiao-Rong; Sun, Yuan-Yuan; Zhang, Ming; Li, Kan; Li, Qiu-Huan; Zhang, Hong; Liu, De-Shan

    2015-01-01

    Objective: To explore the experiences of patients with abnormal extubation of PICC tubes. Methods: Using phenomenological research methods, 15 cases of patients with abnormal extubation of PICC tubes were enrolled in semi-structured interviews. Data were analyzed by Nancy’s phenomenological procedure. Results: After abnormal extubation, patients exhibited conflicting complicated mood which combined negative experience and positive experience. Negative experience was mainly for complaint, helpless, worry and fear. Positive experience was mainly for relief and peace of mind. Conclusions: Patients with abnormal extubation often possessed negative experience. So nursing staff should be suggested to communicate with patients before extubation in order to reduce the dispute between nurses and patients. At the same time, we should summarize and analyze the reasons and factors for abnormal extubation, and take targeted intervention measures in clinical to ensure the safety and effectiveness of PICC extubation. PMID:26770567

  10. The unrecognised difficult extubation: a call for vigilance.

    PubMed

    Antoine, J; Hussain, Z; El-Sayed, I; Apfel, C C

    2010-09-01

    Tracheal extubation remains a critical and often overlooked period of difficult airway management. A 66-year-old man, scheduled for C5-C7 anterior fusion, with an easy view of the vocal cords, presented with a sublaryngeal obstruction that required a reduced tracheal tube size. Despite correct tube placement, intra-operative ventilation remained difficult. At the end of surgery a pulsatile tracheal compression was fibreopticially observed above the carina. After discussion with the attending otolaryngologist, neuromuscular blockade was antagonised and the patient was able to maintain normal minute volumes while spontaneously ventilating. With the otolaryngologist present, and with the patient conscious, the trachea was successfully extubated over an airway exchange catheter. A subsequent CT scan revealed an impingement of the trachea by the innominate artery and a mildly ectatic ascending and descending aorta that, in conjunction with tracheomalacia and neuromuscular blockade, could explain the observed signs and symptoms.

  11. Developing a predictive risk model for first-line antiretroviral therapy failure in South Africa

    PubMed Central

    Rohr, Julia K; Ive, Prudence; Horsburgh, C Robert; Berhanu, Rebecca; Shearer, Kate; Maskew, Mhairi; Long, Lawrence; Sanne, Ian; Bassett, Jean; Ebrahim, Osman; Fox, Matthew P

    2016-01-01

    Introduction A substantial number of patients with HIV in South Africa have failed first-line antiretroviral therapy (ART). Although individual predictors of first-line ART failure have been identified, few studies in resource-limited settings have been large enough for predictive modelling. Understanding the absolute risk of first-line failure is useful for patient monitoring and for effectively targeting limited resources for second-line ART. We developed a predictive model to identify patients at the greatest risk of virologic failure on first-line ART, and to estimate the proportion of patients needing second-line ART over five years on treatment. Methods A cohort of patients aged ≥18 years from nine South African HIV clinics on first-line ART for at least six months were included. Viral load measurements and baseline predictors were obtained from medical records. We used stepwise selection of predictors in accelerated failure-time models to predict virologic failure on first-line ART (two consecutive viral load levels >1000 copies/mL). Multiple imputations were used to assign missing baseline variables. The final model was selected using internal-external cross-validation maximizing model calibration at five years on ART, and model discrimination, measured using Harrell's C-statistic. Model covariates were used to create a predictive score for risk group of ART failure. Results A total of 72,181 patients were included in the analysis, with an average of 21.5 months (IQR: 8.8–41.5) of follow-up time on first-line ART. The final predictive model had a Weibull distribution and the final predictors of virologic failure were men of all ages, young women, nevirapine use in first-line regimen, low baseline CD4 count, high mean corpuscular volume, low haemoglobin, history of TB and missed visits during the first six months on ART. About 24.4% of patients in the highest quintile and 9.4% of patients in the lowest quintile of risk were predicted to experience

  12. Multiscale Model Predicts Tissue-Level Failure From Collagen Fiber-Level Damage

    PubMed Central

    Hadi, Mohammad F.; Sander, Edward A.; Barocas, Victor H.

    2013-01-01

    Excessive tissue-level forces communicated to the microstructure and extracellular matrix of soft tissues can lead to damage and failure through poorly understood physical processes that are multiscale in nature. In this work, we propose a multiscale mechanical model for the failure of collagenous soft tissues that incorporates spatial heterogeneity in the microstructure and links the failure of discrete collagen fibers to the material response of the tissue. The model, which is based on experimental failure data derived from different collagen gel geometries, was able to predict the mechanical response and failure of type I collagen gels, and it demonstrated that a fiber-based rule (at the micrometer scale) for discrete failure can strongly shape the macroscale failure response of the gel (at the millimeter scale). The model may be a useful tool in predicting the macroscale failure conditions for soft tissues and engineered tissue analogs. In addition, the multiscale model provides a framework for the study of failure in complex fiber-based mechanical systems in general. PMID:22938372

  13. Real-time forecasting and predictability of catastrophic failure events: from rock failure to volcanoes and earthquakes

    NASA Astrophysics Data System (ADS)

    Main, I. G.; Bell, A. F.; Naylor, M.; Atkinson, M.; Filguera, R.; Meredith, P. G.; Brantut, N.

    2012-12-01

    Accurate prediction of catastrophic brittle failure in rocks and in the Earth presents a significant challenge on theoretical and practical grounds. The governing equations are not known precisely, but are known to produce highly non-linear behavior similar to those of near-critical dynamical systems, with a large and irreducible stochastic component due to material heterogeneity. In a laboratory setting mechanical, hydraulic and rock physical properties are known to change in systematic ways prior to catastrophic failure, often with significant non-Gaussian fluctuations about the mean signal at a given time, for example in the rate of remotely-sensed acoustic emissions. The effectiveness of such signals in real-time forecasting has never been tested before in a controlled laboratory setting, and previous work has often been qualitative in nature, and subject to retrospective selection bias, though it has often been invoked as a basis in forecasting natural hazard events such as volcanoes and earthquakes. Here we describe a collaborative experiment in real-time data assimilation to explore the limits of predictability of rock failure in a best-case scenario. Data are streamed from a remote rock deformation laboratory to a user-friendly portal, where several proposed physical/stochastic models can be analysed in parallel in real time, using a variety of statistical fitting techniques, including least squares regression, maximum likelihood fitting, Markov-chain Monte-Carlo and Bayesian analysis. The results are posted and regularly updated on the web site prior to catastrophic failure, to ensure a true and and verifiable prospective test of forecasting power. Preliminary tests on synthetic data with known non-Gaussian statistics shows how forecasting power is likely to evolve in the live experiments. In general the predicted failure time does converge on the real failure time, illustrating the bias associated with the 'benefit of hindsight' in retrospective analyses

  14. Peridynamics for failure and residual strength prediction of fiber-reinforced composites

    NASA Astrophysics Data System (ADS)

    Colavito, Kyle

    Peridynamics is a reformulation of classical continuum mechanics that utilizes integral equations in place of partial differential equations to remove the difficulty in handling discontinuities, such as cracks or interfaces, within a body. Damage is included within the constitutive model; initiation and propagation can occur without resorting to special crack growth criteria necessary in other commonly utilized approaches. Predicting damage and residual strengths of composite materials involves capturing complex, distinct and progressive failure modes. The peridynamic laminate theory correctly predicts the load redistribution in general laminate layups in the presence of complex failure modes through the use of multiple interaction types. This study presents two approaches to obtain the critical peridynamic failure parameters necessary to capture the residual strength of a composite structure. The validity of both approaches is first demonstrated by considering the residual strength of isotropic materials. The peridynamic theory is used to predict the crack growth and final failure load in both a diagonally loaded square plate with a center crack, as well as a four-point shear specimen subjected to asymmetric loading. This study also establishes the validity of each approach by considering composite laminate specimens in which each failure mode is isolated. Finally, the failure loads and final failure modes are predicted in a laminate with various hole diameters subjected to tensile and compressive loads.

  15. Multipulse laser-induced failure prediction for Mo metal mirrors

    NASA Astrophysics Data System (ADS)

    Becker, Michael F.; Ma, Chun C.; Walser, Rodger M.

    1991-06-01

    In combination with known thermomechanical fatigue data for Mo we have applied the Transient Photothermal Deflection (TPD) technique to develop a model f the N-on-i damage ofMo mirrors to predict their multipulse lifetimes. In laser-damage experiments to verify the model mechanically polished Mo mirrors were irradiated with 10 ns Nd:YAG laser pulses at 1064 nm at a 10 Hz rep rate. In the TPD experiments the approximately 600 jtm diameter Nd:YAG laser spot was probed off axis by a smaller HeNe laser beam whose deflection was detected by a fast bicell photodetector and amplifier. Digitized photodetector waveforms indicated that the surface angular deflection could be converted into surfae disp1zement. In addition thermal modelling of the vertical heat distribution enabled the peak surface-deflection signal to be converted into peak surfwe temperawre. The thermomechanical model was verified by both the experimental and model results. Conventional mechanical fatigue data for Mo were used to derive a predictive equation for the laser-accumulation lifetime of Mo mirrors. Experiments were performed with one to 1O'' pulses per site yielding laser-damage thresholds and accumulation curves. The accumulation behavior predicted from measurennts of mechanical fatigue was in excellent agreement with the measured behavior. It is possible that data on high-cycle ( mechanical fatigue can be used to predict the performance of optical surfaces at equally large values of N.

  16. TNF Receptor 1/2 Predict Heart Failure Risk in Type 2 Diabetes Mellitus Patients.

    PubMed

    Ping, Zhang; Aiqun, Ma; Jiwu, Li; Liang, Shao

    2017-04-06

    Inflammation plays an important role in heart failure and diabetes mellitus. Traditional serum markers have limited predictive value in heart failure and diabetes. TNFR1 and TNFR2 (TNFR1/2) have been proven to be strongly associated with heart failure and diabetes complications. This study aimed to assess the association of sTNFR1 and sTNFR2 levels and incidental HF risk in diabetes patients.We detected the mRNA, protein, and serum expression of TNFR1/2, their downstream signaling pathway protein NF-kB, and JNK expression and some traditional serum inflammatory markers in a heart failure group without diabetes mellitus or abnormal glucose tolerance (n = 84), a diabetes mellitus group without heart failure (n = 86), and a heart failure with diabetes mellitus group (n = 86).TNFR1/2 were significantly higher in patients with heart failure and diabetes mellitus based on mRNA expression to protein expression and serum expression. However, there were no differences in mRNA, protein, and serum levels of TNFR1/2 between the HF group and DM group. Furthermore, there were no differences between the groups in some traditional serum inflammatory markers.This study demonstrated higher expressions of TNFR, NF-kB, and JNK in patients with heart failure and diabetes mellitus. Compared with traditional serum markers, TNFR1 and TNFR2 are associated with heart failure risk in type 2 diabetes mellitus patients.

  17. Can success and failure be predicted for baccalaureate graduates on the computerized NCLEX-RN?

    PubMed

    Seldomridge, Lisa A; Dibartolo, Mary C

    2004-01-01

    The current shortage of nurses and declining national pass rate on the National Council Licensure Examination for Registered Nurses (NCLEX-RN) has heightened educators' interest in identifying students at risk for failure. A retrospective descriptive study was conducted at a rural, public baccalaureate nursing program to determine variables that best predict NCLEX-RN success and failure. Data collected from 1998 through 2002 (N = 186) included entry as native or transfer student, preadmission grade point average (GPA), GPA after completing one semester of nursing courses, cumulative GPA at graduation, grades earned in prerequisite and core nursing courses, test averages in beginning and advanced medical/surgical nursing courses, and performance on the National League for Nursing Comprehensive Achievement Test for Baccalaureate Students (NLNCATBS). Logistic regression analysis revealed that a combination of test average in advanced medical/surgical nursing and percentile score on the NLNCATBS predicted 94.7 percent of NCLEX-RN passes and 33.3 percent of failures. The combination of NLNCATBS score and pathophysiology grade predicted 93.3 percent of NCLEX-RN passes and 50 percent of failures. Although success could be accurately predicted across all models, predicting failure was far more difficult.

  18. Predicting the Failure Behavior of Textile Composite Laminates by Using a Multi-Scale Correlating Approach

    NASA Astrophysics Data System (ADS)

    Deng, Yan; Chen, Xiuhua; Wang, Hai

    2015-12-01

    This paper investigates the elastic and failure behavior of textile composite laminates by using an analytical multi-scale correlating approach. The analyses are performed under the four scale levels, i.e. the laminate scale, representative unit cell (RUC) scale, tow architecture scale and fiber/matrix scale levels. The correlation between different scales is derived based on the continuum mechanics and homogenization method from which the stress and strain fields in multiple scales can be obtained concurrently. Effective modulus and ultimate failure strengths of different textile composite (plain weave, twill weave and satin weave) laminates are predicted solely from the corresponding constituent properties, braid geometrical parameters and lay-up. The damage and failure mechanisms at the constituent level are also determined by the micromechanical failure criteria. All the predicted results compare favorably with available experimental data. Parametric studies are also performed to examine the effect of various mechanical and geometrical parameters on the resulting mechanical properties.

  19. A new method for failure prediction of SR-200 beryllium sheet structures

    NASA Technical Reports Server (NTRS)

    Papados, P. P.; Roschke, P. N.

    1994-01-01

    Contemporary applications of failure criteria frequently incorporate two-dimensional or simplified three-dimensional methodologies for prediction of stresses. Motivation behind the development of a new multi-dimensional failure criterion is due mainly to the lack of a sufficiently accurate mathematical tool that accounts for the behavior of brittle material with anisotropic properties. Such a criterion should be able to provide a reliable maximum load estimate so that design of the structure is not penalized in terms of excessive weight requirements. The failure criterion developed is represented by a fracture surface in a six-dimensional stress space. The criterion is applied for failure prediction of SR-200 beryllium sheet structures, a non-homogeneous orthotropic material used widely in space applications. Two experiments are used to verify the criterion.

  20. Probability of failure prediction for step-stress fatigue under sine or random stress

    NASA Technical Reports Server (NTRS)

    Lambert, R. G.

    1979-01-01

    A previously proposed cumulative fatigue damage law is extended to predict the probability of failure or fatigue life for structural materials with S-N fatigue curves represented as a scatterband of failure points. The proposed law applies to structures subjected to sinusoidal or random stresses and includes the effect of initial crack (i.e., flaw) sizes. The corrected cycle ratio damage function is shown to have physical significance.

  1. Methodology to predict the number of forced outages due to creep failure

    SciTech Connect

    Palermo, J.V. Jr.

    1996-12-31

    All alloy metals at a temperature above 950 degrees Fahrenheit experience creep damage. Creep failures in boiler tubes usually begin after 25 to 40 years of operation. Since creep damage is irreversible, the only remedy is to replace the tube sections. By predicting the number of failures per year, the utility can make the best economic decision concerning tube replacement. This paper describes a methodology to calculate the number of forced outages per yea due to creep failures. This methodology is particularly useful to utilities that have boilers that have at least 25 years of operation.

  2. Endothelial Cell Density to Predict Endothelial Graft Failure After Penetrating Keratoplasty

    PubMed Central

    Lass, Jonathan H.; Sugar, Alan; Benetz, Beth Ann; Beck, Roy W.; Dontchev, Mariya; Gal, Robin L.; Kollman, Craig; Gross, Robert; Heck, Ellen; Holland, Edward J.; Mannis, Mark J.; Raber, Irving; Stark, Walter; Stulting, R. Doyle

    2010-01-01

    Objective To determine whether preoperative and/or postoperative central endothelial cell density (ECD) and its rate of decline postoperatively are predictive of graft failure caused by endothelial decompensation following penetrating keratoplasty to treat a moderate-risk condition, principally, Fuchs dystrophy or pseudophakic corneal edema. Methods In a subset of Cornea Donor Study participants, a central reading center determined preoperative and postoperative ECD from available specular images for 17 grafts that failed because of endothelial decompensation and 483 grafts that did not fail. Results Preoperative ECD was not predictive of graft failure caused by endothelial decompensation (P = .91). However, the 6-month ECD was predictive of subsequent failure (P < .001). Among those that had not failed within the first 6 months, the 5-year cumulative incidence (±95% confidence interval) of failure was 13% (±12%) for the 33 participants with a 6-month ECD of less than 1700 cells/mm2 vs 2%(±3%) for the 137 participants with a 6-monthECDof 2500 cells/mm2 or higher. After 5 years’ follow-up, 40 of 277 participants (14%) with a clear graft had an ECD below 500 cells/mm2. Conclusions Preoperative ECD is unrelated to graft failure from endothelial decompensation, whereas there is a strong correlation of ECD at 6 months with graft failure from endothelial decompensation. A graft can remain clear after 5 years even when the ECD is below 500 cells/mm2. PMID:20065219

  3. An investigation of gear mesh failure prediction techniques. M.S. Thesis - Cleveland State Univ.

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James J.

    1989-01-01

    A study was performed in which several gear failure prediction methods were investigated and applied to experimental data from a gear fatigue test apparatus. The primary objective was to provide a baseline understanding of the prediction methods and to evaluate their diagnostic capabilities. The methods investigated use the signal average in both the time and frequency domain to detect gear failure. Data from eleven gear fatigue tests were recorded at periodic time intervals as the gears were run from initiation to failure. Four major failure modes, consisting of heavy wear, tooth breakage, single pits, and distributed pitting were observed among the failed gears. Results show that the prediction methods were able to detect only those gear failures which involved heavy wear or distributed pitting. None of the methods could predict fatigue cracks, which resulted in tooth breakage, or single pits. It is suspected that the fatigue cracks were not detected because of limitations in data acquisition rather than in methodology. Additionally, the frequency response between the gear shaft and the transducer was found to significantly affect the vibration signal. The specific frequencies affected were filtered out of the signal average prior to application of the methods.

  4. Feasibility of using adaptive logic networks to predict compressor unit failure

    SciTech Connect

    Armstrong, W.W.; Chungying Chu; Thomas, M.M.

    1995-12-31

    In this feasibility study, an adaptive logic network (ALN) was trained to predict failures of turbine-driven compressor units using a large database of measurements. No expert knowledge about compressor systems was involved. The predictions used only the statistical properties of the measurements and the indications of failure types. A fuzzy set was used to model measurements typical of normal operation. It was constrained by a requirement imposed during ALN training, that it should have a shape similar to a Gaussian density, more precisely, that its logarithm should be convex-up. Initial results obtained using this approach to knowledge discovery in the database were encouraging.

  5. Predicting age of ovarian failure after radiation to a field that includes the ovaries

    SciTech Connect

    Wallace, W. Hamish B. . E-mail: Hamish.Wallace@ed.ac.uk; Thomson, Angela B.; Saran, Frank; Kelsey, Tom W.

    2005-07-01

    Purpose: To predict the age at which ovarian failure is likely to develop after radiation to a field that includes the ovary in women treated for cancer. Methods and Materials: Modern computed tomography radiotherapy planning allows determination of the effective dose of radiation received by the ovaries. Together with our recent assessment of the radiosensitivity of the human oocyte, the effective surviving fraction of primordial oocytes can be determined and the age of ovarian failure, with 95% confidence limits, predicted for any given dose of radiotherapy. Results: The effective sterilizing dose (ESD: dose of fractionated radiotherapy [Gy] at which premature ovarian failure occurs immediately after treatment in 97.5% of patients) decreases with increasing age at treatment. ESD at birth is 20.3 Gy; at 10 years 18.4 Gy, at 20 years 16.5 Gy, and at 30 years 14.3 Gy. We have calculated 95% confidence limits for age at premature ovarian failure for estimated radiation doses to the ovary from 1 Gy to the ESD from birth to 50 years. Conclusions: We report the first model to reliably predict the age of ovarian failure after treatment with a known dose of radiotherapy. Clinical application of this model will enable physicians to counsel women on their reproductive potential following successful treatment.

  6. Prediction of Ductile Failure in the Stretch-Forming of AA2024 Sheets

    SciTech Connect

    Vallellano, C.; Guzman, C.; Garcia-Lomas, F. J.

    2007-05-17

    A number of ductile failure criteria are nowadays being used to predict the formability of aluminium alloy sheets. Generally speaking, integral criteria (e.g. those proposed by Cockcroft and Latham, Brozzo et al., Oyane et al Chaouadi et al., etc.) have been probed to work well when the principal strains are of opposite sign, i.e. in the left side of the Forming Limit Diagram (FLD). However, when tensile biaxial strains are present, as occurs in stretch-forming practice, their predictions are usually very poor and even non-conservatives. As an alternative, local criteria, such as the classical Tresca's and Bressan and Williams' criteria, have demonstrated a good capability to predict the failure in some automotive aluminum alloys under stretching. The present work analyses experimentally and numerically the failure in AA2024-T3 sheets subjected to biaxial stretching. A series of out-of-plane stretching tests have been simulated using ABAQUS. The experimental and the numerical FLD for different failure criteria are compared. The influence on the failure of the hydrostatic pressure and the normal stress to the fracture plane is also discussed.

  7. Multiple immune deviations predictive for IVF failure as possible markers for IVIG therapy.

    PubMed

    Chernyshov, Viktor P; Dons'koi, Boris V; Sudoma, Iryna O; Goncharova, Yana O

    2016-08-01

    Recently we have shown that immune deviations (ID) may predict IVF failure. Benefit from IVIG therapy was observed in 115 women with repeated IVF failure according to proposed multiple ID that appeared unfavorable for implantation and live birth. Group of 123 women with repeated IVF failure without IVIG therapy was compared with former group. Immune phenotype and NK activity of peripheral blood lymphocytes were studied by flow cytometry. Potentially predictive for IVF failure ID included elevated expression of CD56, CD158a in T lymphocytes, decreased levels of CD4T lymphocytes, up-regulated expression of HLA DR in CD8+ T cells and NK cells, elevated number of NK cells and increased NK cytotoxicity, increased or decreased expression of CD158a and CD8 in NK cells. Three or more ID may predict implantation failure to a greater degree than one or two ID. In women receiving IVIG in subgroups with 0-1 and 2 ID, there was no increase in implantation rate (IR) and live birth rate (LBR) after IVIG in comparison with patients with the same number of ID but without IVIG correction. After IVIG therapy decreased IR and LBR were restored in women with three or more immune deviations. Multiple immune deviations indicate IVF patients who may benefit from IVIG therapy. IVIG seems to convert "unfavorable" immune phenotype to "favorable" one.

  8. Time-dependent Predictive Values of Prognostic Biomarkers with Failure Time Outcome.

    PubMed

    Zheng, Yingye; Cai, Tianxi; Pepe, Margaret S; Levy, Wayne C

    2008-01-01

    In a prospective cohort study, information on clinical parameters, tests and molecular markers is often collected. Such information is useful to predict patient prognosis and to select patients for targeted therapy. We propose a new graphical approach, the positive predictive value (PPV) curve, to quantify the predictive accuracy of prognostic markers measured on a continuous scale with censored failure time outcome. The proposed method highlights the need to consider both predictive values and the marker distribution in the population when evaluating a marker, and it provides a common scale for comparing different markers. We consider both semiparametric and nonparametric based estimating procedures. In addition, we provide asymptotic distribution theory and resampling based procedures for making statistical inference. We illustrate our approach with numerical studies and datasets from the Seattle Heart Failure Study.

  9. Predicting Outcomes of Hospitalization for Heart Failure Using Logistic Regression and Knowledge Discovery Methods

    PubMed Central

    Phillips, Kirk T.; Street, W. Nick

    2005-01-01

    The purpose of this study is to determine the best prediction of heart failure outcomes, resulting from two methods -- standard epidemiologic analysis with logistic regression and knowledge discovery with supervised learning/data mining. Heart failure was chosen for this study as it exhibits higher prevalence and cost of treatment than most other hospitalized diseases. The prevalence of heart failure has exceeded 4 million cases in the U.S.. Findings of this study should be useful for the design of quality improvement initiatives, as particular aspects of patient comorbidity and treatment are found to be associated with mortality. This is also a proof of concept study, considering the feasibility of emerging health informatics methods of data mining in conjunction with or in lieu of traditional logistic regression methods of prediction. Findings may also support the design of decision support systems and quality improvement programming for other diseases. PMID:16779367

  10. Prediction of Brittle Failure for TBM Tunnels in Anisotropic Rock: A Case Study from Northern Norway

    NASA Astrophysics Data System (ADS)

    Dammyr, Øyvind

    2016-06-01

    Prediction of spalling and rock burst is especially important for hard rock TBM tunneling, because failure can have larger impact than in a drill and blast tunnel and ultimately threaten excavation feasibility. The majority of research on brittle failure has focused on rock types with isotropic behavior. This paper gives a review of existing theory and its application before a 3.5-m-diameter TBM tunnel in foliated granitic gneiss is used as a case to study brittle failure characteristics of anisotropic rock. Important aspects that should be considered in order to predict brittle failure in anisotropic rock are highlighted. Foliation is responsible for considerable strength anisotropy and is believed to influence the preferred side of v-shaped notch development in the investigated tunnel. Prediction methods such as the semi- empirical criterion, the Hoek- Brown brittle parameters, and the non-linear damage initiation and spalling limit method give reliable results; but only as long as the angle between compression axis and foliation in uniaxial compressive tests is relevant, dependent on the relation between tunnel trend/plunge, strike/dip of foliation, and tunnel boundary stresses. It is further demonstrated that local in situ stress variations, for example, due to the presence of discontinuities, can have profound impact on failure predictions. Other carefully documented case studies into the brittle failure nature of rock, in particular anisotropic rock, are encouraged in order to expand the existing and relatively small database. This will be valuable for future TBM planning and construction stages in highly stressed brittle anisotropic rock.

  11. A model for predicting embankment slope failures in clay-rich soils; A Louisiana example

    NASA Astrophysics Data System (ADS)

    Burns, S. F.

    2015-12-01

    A model for predicting embankment slope failures in clay-rich soils; A Louisiana example It is well known that smectite-rich soils significantly reduce the stability of slopes. The question is how much smectite in the soil causes slope failures. A study of over 100 sites in north and south Louisiana, USA, compared slopes that failed during a major El Nino winter (heavy rainfall) in 1982-1983 to similar slopes that did not fail. Soils in the slopes were tested for per cent clay, liquid limits, plasticity indices and semi-quantitative clay mineralogy. Slopes with the High Risk for failure (85-90% chance of failure in 8-15 years after construction) contained soils with a liquid limit > 54%, a plasticity index over 29%, and clay contents > 47%. Slopes with an Intermediate Risk (55-50% chance of failure in 8-15 years) contained soils with a liquid limit between 36-54%, plasticity index between 16-19%, and clay content between 32-47%. Slopes with a Low Risk chance of failure (< 5% chance of failure in 8-15 years after construction) contained soils with a liquid limit < 36%, a plasticity index < 16%, and a clay content < 32%. These data show that if one is constructing embankments and one wants to prevent slope failure of the 3:1 slopes, check the above soil characteristics before construction. If the soils fall into the Low Risk classification, construct the embankment normally. If the soils fall into the High Risk classification, one will need to use lime stabilization or heat treatments to prevent failures. Soils in the Intermediate Risk class will have to be evaluated on a case by case basis.

  12. Sonographical predictive markers of failure of induction of labour in term pregnancy.

    PubMed

    Brik, Maia; Mateos, Silvia; Fernandez-Buhigas, Irene; Garbayo, Paloma; Costa, Gloria; Santacruz, Belen

    2017-02-01

    Predictive markers of failure of induction of labour in term pregnancy were evaluated. A prospective study including 245 women attending induction of labour was performed. The inclusion criteria were singleton pregnancies, gestational age 37-42 weeks and the main outcomes were failure of induction, induction to delivery interval and mode of delivery. Women with a longer cervical length prior to induction (CLpi) had a higher rate of failure of induction (30.9 ± 6.8 vs. 23.9 ± 9.3, p < .001). BMI was higher and maternal height was lower in the group of caesarean section compared to vaginal delivery (33.1 ± 8 vs. 29.3 ± 4.6, 160 ± 5 vs. 164 ± 5, p < .001, respectively). A shorter CLpi correlated with a shorter induction to delivery interval (R Pearson .237, p < .001). In the regression analysis, for failure of induction the only independent predictor was the CL prior to induction. Therefore, the CLpi is an independent factor for prediction of failure of induction of labour.

  13. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    SciTech Connect

    Duffy, Stephen

    2013-09-09

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  14. [Failure Prediction of Power-Shift Steering Transmission Based on Oil Spectral Analysis with Wiener Process].

    PubMed

    Liu, Yong; Ma, Biao; Zheng, Chang-song; Xie, Shang-yu

    2015-09-01

    The most common methodology used in element concentration measurement and analyzing of wear particles is Atomic emission (AE) spectroscopy. As an indirect measuring method, the oil spectral data is introduced to indicate the performance degradation and the residual life prediction in the reliability evaluation of Power shift steering transmission (PSST). Stochastic methods especially the Wiener process is convenient in solving and analyzing the unitary degradation failure indicated by the oil spectral data. The oil data have been sampled in the real operating condition, and the data set has more than 50 samples taken from PSST. The mean values and time-dependent characteristics of three indicating elements are statistically obtained by the linear regression analysis. The model of the degradation and failure prediction has been proposed based on the Wiener process with the positive drift. For modeling and simulation the software R was used. Therefore, the trend curves of diffusion process with their First Hitting Time have been predicted. Through comparison, the time intervals of condition-based maintenance have been extended as 27 Mh (15.9%). This will save the cost of maintenances by eliminate the preventive maintained cycles. The advantage and novelty of the outcomes presented in the article are that the stochastic process might be applied for predicting the degradation failure occurrence and also for optimizing the maintenance intervals and the cost-benefit. As might be expected, the method can be extended to other cases of wear prediction and evaluation in complex mechanical system.

  15. Avionics equipment failure prediction based on genetic programming and grey model

    NASA Astrophysics Data System (ADS)

    Deng, Xiujian; Luo, Qiang; Zhao, Yiyang; Feng, Qi

    2017-01-01

    Avionics equipment failure prediction by conventional GM (Grey Model) may yield large forecasting errors. Combining GM (1, 1) model with genetic programming algorithm, a kind of GP-GM (1, 1) forecast model was established to minimize such errors. Forecasting sequence was calculated by means of GM (1, 1) model, then genetic programming algorithm was used to modify them further, and the degradation trend prediction of characteristic parameters of avionics equipment was realized. The validity of GP-GM (1, 1) prediction model was testified by tracking and forecasting the experiment data of avionics equipment in real environment.

  16. Predicting in vivo failure of rotary nickel-titanium endodontic instruments under cyclic fatigue.

    PubMed

    Stojanac, Igor; Drobac, Milan; Petrovic, Ljubomir; Atanackovic, Teodor

    2012-01-01

    The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress need not necessarily occur at the outer layer. On the basis of this observation, the Coffin-Manson relation was modified with parameters determined from this experiment. Results showed that the number of cycles to failure was influenced by the angle and radius of canal curvature and the size of instrument at the beginning of canal curvature. The resulting quantitative mathematical relation could be used to predict the lifespan of rotary Ni-Ti endodontic instruments under clinical conditions and thereby reduce the incidence of instrument failure in vivo.

  17. Prediction of failure envelopes of composite tubes subjected to biaxial loadings

    NASA Astrophysics Data System (ADS)

    Gargiulo, C.; Marchetti, M.; Rizzo, A.

    1996-09-01

    Practical cylindrical structures including pressure vessels, pipes, drive shafts and rochet motors are usually subjected to complex loads involving biaxial or triaxial stress systems. In particular, filamentary composite vessels are used in applications of Space Shuttle tankage, as well as for the storage of fluids in various commercial applications. The object of this work is to provide numerical and experiment data on the strength of filament wound carbon fibre reinforced epoxy resin thin tubes under biaxial loading conditions. Internal or external pressure and axial loads are applied simultaneously to produce a variety of biaxial stress conditions. The effects of the winding angle of the fibre reinforcements on the failure loads of the pipes have been examined. Finite elements and thin shell analysis have been applied to the problem using different failure criteria in order to predict the specimen's failure for a comparison with experimental results.

  18. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    PubMed

    Alani, Amir M; Faramarzi, Asaad

    2015-06-10

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  19. Predicting remaining life by fusing the physics of failure modeling with diagnostics

    NASA Astrophysics Data System (ADS)

    Kacprzynski, G. J.; Sarlashkar, A.; Roemer, M. J.; Hess, A.; Hardman, B.

    2004-03-01

    Technology that enables failure prediction of critical machine components (prognostics) has the potential to significantly reduce maintenance costs and increase availability and safety. This article summarizes a research effort funded through the U.S. Defense Advanced Research Projects Agency and Naval Air System Command aimed at enhancing prognostic accuracy through more advanced physics-of-failure modeling and intelligent utilization of relevant diagnostic information. H-60 helicopter gear is used as a case study to introduce both stochastic sub-zone crack initiation and three-dimensional fracture mechanics lifing models along with adaptive model updating techniques for tuning key failure mode variables at a local material/damage site based on fused vibration features. The overall prognostic scheme is aimed at minimizing inherent modeling and operational uncertainties via sensed system measurements that evolve as damage progresses.

  20. Control theory prediction of resolved Cheyne-Stokes respiration in heart failure.

    PubMed

    Sands, Scott A; Edwards, Bradley A; Kee, Kirk; Stuart-Andrews, Christopher; Skuza, Elizabeth M; Roebuck, Teanau; Turton, Anthony; Hamilton, Garun S; Naughton, Matthew T; Berger, Philip J

    2016-11-01

    Cheyne-Stokes respiration (CSR) foretells deleterious outcomes in patients with heart failure. Currently, the size of therapeutic intervention is not guided by the patient's underlying pathophysiology. In theory, the intervention needed to resolve CSR, as a control system instability (loop gain >1), can be predicted knowing the baseline loop gain and how much it falls with therapy.In 12 patients with heart failure, we administered an inspiratory carbon dioxide fraction of 1-3% during CSR (n=95 interventions) as a means to reduce loop gain. We estimated the loop gain on therapy (LGtherapy), using the baseline loop gain (using hyperpnoea length/cycle length) and its expected reduction (18% per 1% inspired carbon dioxide), and tested the specific hypothesis that LGtherapy predicts CSR persistence (LGtherapy >1) versus resolution (LGtherapy <1).As predicted, when LGtherapy >1.0, CSR continued during therapy in 23 out of 25 (92%) trials. A borderline loop gain zone (0.8predictive insight into CSR resolution in heart failure. Thus, we now have a means to calculate the size of interventions needed to ameliorate CSR on a patient-by-patient basis.

  1. Acute liver failure in Japan: definition, classification, and prediction of the outcome.

    PubMed

    Sugawara, Kayoko; Nakayama, Nobuaki; Mochida, Satoshi

    2012-08-01

    Acute liver failure is a clinical syndrome characterized by hepatic encephalopathy and a bleeding tendency due to severe impairment of liver function caused by massive or submassive liver necrosis. Viral hepatitis is the most important and frequent cause of acute liver failure in Japan. The diagnostic criteria for fulminant hepatitis, including that caused by viral infections, autoimmune hepatitis, and drug allergy induced-liver damage, were first established in 1981. Considering the discrepancies between the definition of fulminant hepatitis in Japan and the definitions of acute liver failure in the United States and Europe, the Intractable Hepato-Biliary Disease Study Group established the diagnostic criteria for "acute liver failure" for Japan in 2011, and performed a nationwide survey of patients seen in 2010 to clarify the demographic and clinical features and outcomes of these patients. According to the survey, the survival rates of patients receiving medical treatment alone were low, especially in those with hepatic encephalopathy, despite artificial liver support, consisting of plasma exchange and hemodiafiltration, being provided to almost all patients in Japan. Thus, liver transplantation is inevitable to rescue most patients with hepatic encephalopathy. The indications for liver transplantation had, until recently, been determined according to the guideline published by the Acute Liver Failure Study Group in 1996. Recently, however, the Intractable Hepato-Biliary Disease Study Group established a scoring system to predict the outcomes of acute liver failure patients. Algorithms for outcome prediction have also been developed based on data-mining analyses. These novel guidelines need further evaluation to determine their usefulness.

  2. Plasma Levels of sRAGE, Loss of Aeration and Weaning Failure in ICU Patients: A Prospective Observational Multicenter Study

    PubMed Central

    Jabaudon, Matthieu; Perbet, Sébastien; Pereira, Bruno; Soummer, Alexis; Roszyk, Laurence; Guérin, Renaud; Futier, Emmanuel; Lu, Qin; Bazin, Jean-Etienne; Sapin, Vincent; Rouby, Jean-Jacques; Constantin, Jean-Michel

    2013-01-01

    Rationale Postextubation distress after a successful spontaneous breathing trial (SBT) is associated with increased morbidity and mortality. Lung ultrasound determination of changes in lung aeration predicts weaning failure. It remains unknown whether this derecruitment is related to alveolar epithelial dysfunction or not. Objective To verify whether lung alveolar type I epithelial cell injury marker sRAGE (soluble form of the receptor for advanced glycation end-products) is predictive of postextubation distress and weaning failure or not, and to verify whether plasma sRAGE levels can be related to lung derecruitment during the process of weaning from mechanical ventilation or not. Interventions, Measurements 88 patients from 2 intensive care units were included in this observational prospective study. Plasma sRAGE levels were measured in duplicate by ELISA before, at the end of a 60-minute SBT, and 4 hours after extubation. To quantify lung aeration, a lung ultrasound score was calculated. Main Results 34% of extubated patients experienced postextubation distress. Patients with or without postextubation distress had comparable sRAGE levels before SBT, after SBT, and 4 hours after extubation. In patients with postextubation distress, sRAGE levels were not predictive of the need for mechanical ventilation. sRAGE levels were not associated with lung aeration as assessed by echography. Patients who succeeded SBT (86%) and those who failed (14%) had no differences in sRAGE levels, before (median 1111 vs 1021 pg/mL, p = 0,87) and at the end of SBT (1165 vs 1038 pg/mL, p = 0.74). Conclusions Plasma levels of sRAGE do not predict postextubation distress or SBT failure/success in patients weaning from mechanical ventilation. Lung aeration loss during a successful weaning trial predicts postextubation distress, but may not be evaluable by plasma levels of sRAGE, a marker of alveolar type I epithelial cell injury. Trial Registration ClinicalTrials.gov NCT01098773

  3. Cognitive Failure and Alexithymia and Predicting High–Risk Behaviors of Students With Learning Disabilities

    PubMed Central

    Abbasi, Moslem; Bagyan, Mohammad Javad; Dehghan, Hamidreza

    2014-01-01

    Background: One of the threatening health issues is prevalence of high-risk behaviors in various groups. Because of rapid social changes, it has been considered as of the most important problems of society by health organizations, administrative laws, and social policymakers. Objectives: The aim of this study was to determine the role of cognitive failure and alexithymia in predicting high-risk behaviors of students with learning disabilities. Patients and Methods: This was a correlational research including all 14-16 years old students during 2012-2013 school year in Arak, IR Iran. Eighty students with learning disabilities were sampled by simply random sampling. The data were collected by cognitive failures questionnaire, Toronto alexithymia scale, and high-risk behavior questionnaire. Results: The results showed that high-risk behaviors had significant positive correlations with difficulty identifying feelings (r = 0.321), difficulty describing feelings (r = 0.336), externally oriented thinking (r = 0.248), distractibility (0.292), memory distortion (r = 0.374), blunders (r = 0.335), and names amnesia (r = 0.275). Multiple regression analysis showed that cognitive failure and alexithymia predicted 32% of the total variance of high-risk behaviors. Conclusions: These findings demonstrated that cognitive failure and alexithymia had important roles in strengthening and appearance of high-risk behaviors in students with learning disabilities. Therefore, considering those problems, precautionary actions might be necessary. PMID:25032160

  4. A relation to predict the failure of materials and potential application to volcanic eruptions and landslides.

    PubMed

    Hao, Shengwang; Liu, Chao; Lu, Chunsheng; Elsworth, Derek

    2016-06-16

    A theoretical explanation of a time-to-failure relation is presented, with this relationship then used to describe the failure of materials. This provides the potential to predict timing (tf - t) immediately before failure by extrapolating the trajectory as it asymptotes to zero with no need to fit unknown exponents as previously proposed in critical power law behaviors. This generalized relation is verified by comparison with approaches to criticality for volcanic eruptions and creep failure. A new relation based on changes with stress is proposed as an alternative expression of Voight's relation, which is widely used to describe the accelerating precursory signals before material failure and broadly applied to volcanic eruptions, landslides and other phenomena. The new generalized relation reduces to Voight's relation if stress is limited to increase at a constant rate with time. This implies that the time-derivatives in Voight's analysis may be a subset of a more general expression connecting stress derivatives, and thus provides a potential method for forecasting these events.

  5. A relation to predict the failure of materials and potential application to volcanic eruptions and landslides

    PubMed Central

    Hao, Shengwang; Liu, Chao; Lu, Chunsheng; Elsworth, Derek

    2016-01-01

    A theoretical explanation of a time-to-failure relation is presented, with this relationship then used to describe the failure of materials. This provides the potential to predict timing (tf − t) immediately before failure by extrapolating the trajectory as it asymptotes to zero with no need to fit unknown exponents as previously proposed in critical power law behaviors. This generalized relation is verified by comparison with approaches to criticality for volcanic eruptions and creep failure. A new relation based on changes with stress is proposed as an alternative expression of Voight’s relation, which is widely used to describe the accelerating precursory signals before material failure and broadly applied to volcanic eruptions, landslides and other phenomena. The new generalized relation reduces to Voight’s relation if stress is limited to increase at a constant rate with time. This implies that the time-derivatives in Voight’s analysis may be a subset of a more general expression connecting stress derivatives, and thus provides a potential method for forecasting these events. PMID:27306851

  6. Distinguishing and predicting granular failure via multiscale evolution of contact cycle topologies

    NASA Astrophysics Data System (ADS)

    Pucilowski, Sebastian; Walker, David M.; Tordesillas, Antoinette

    2013-06-01

    We examine the spatial evolution of 3-cycle topologies in the contact networks of 2D and 3D granular media under load experiencing one of two modes of failure at the macroscopic scale: diffused or localised. These mesoscale structures encapsulate kinematical signatures of plastic deformation and thus their destruction or deaths provides a means of tracking or predicting macroscopic failure. A multiscale point pattern analysis quantifies the extent of spatial clustering of these structures within the material throughout loading. In samples undergoing failure through strain localisation, 3-cycle deaths exhibit evidence for spatial clustering well before peak shear stress and shear band nucleation. Detection occurs earlier in the loading history compared to more traditional soil mechanics measures, e.g., porosity maps and particle rotations. Moreover the region of strain localisation is delineated by the spatial distribution of the dying 3-cycle contact topologies. In samples undergoing diffuse failure, no evidence of localisation is detected over short strain intervals suggesting an optimal window size to capture key kinematics, with an aim towards using the spatial behaviour of mesoscopic 3-cycles as a tool to classify macroscopic failure modes.

  7. Prediction of Thromboembolic Events in Heart Failure Patients in Sinus Rhythm: The Hong Kong Heart Failure Registry

    PubMed Central

    Hai, Jo-Jo; Chan, Pak-Hei; Chan, Yap-Hang; Fong, Carol-Ho-Yi; Huang, Duo; Li, Wen-Hua; Yin, Li-Xue; Lau, Chu-Pak; Tse, Hung-Fat; Siu, Chung-Wah

    2016-01-01

    Aim Heart failure (HF) increases the risk of thromboembolic events (TE). Study in a Caucasian population has shown that the CHA2DS2-VASc score predicts TE among HF patients without atrial fibrillation. We sought to assess the usefulness of the CHA2DS2-VASc score in predicting TE in an Asian population and refine the scoring system to improve its predictability of TE among HF patients in sinus rhythm. Methods A total of 1,202 consecutive patients who were admitted to our institution for new-onset HF from 2005 to 2012 and without atrial fibrillation or anticoagulation were retrospectively reviewed. Results The mean age was 77.6 ± 12.2 years and 51.7% were female. After 36.2 ± 30.1 months, 113 (9.4%) developed TE. The annual incidence was 0.54%, 1.54%, 2.98% and 5.04% per year in those who had a CHA2DS2-VASc score of 1, 2–3, 4–5 and ≥6, respectively. In multivariate analysis, age ≥75 years [Hazard ratio (HR) 2.59, 95% confidence interval (CI) 1.23–5.46, p = 0.012), chronic ischemic heart disease (HR 1.54, 95% CI 1.02–2.31, p = 0.040) and chronic kidney disease (HR 1.66, 95% CI 1.09–2.53, p = 0.018) independently predicted TE. Incorporation of chronic ischemic heart disease and chronic kidney disease into the CHA2DS2-VASc score significantly increased the area under the Receiver Operating Curve from 0.57 (95% CI 0.54–0.59) to 0.61 (95% CI 0.55–0.66; p = 0.022). Conclusion The CHA2DS2-VASc score is useful for stratification of the risk of TE among HF patients in sinus rhythm. Incorporation of chronic ischemic heart disease and chronic kidney disease into the score modestly improves its predictive value. PMID:28036365

  8. Liver resection for cancer: New developments in prediction, prevention and management of postresectional liver failure.

    PubMed

    van Mierlo, Kim M C; Schaap, Frank G; Dejong, Cornelis H C; Olde Damink, Steven W M

    2016-12-01

    Hepatic failure is a feared complication that accounts for up to 75% of mortality after extensive liver resection. Despite improved perioperative care, the increasing complexity and extensiveness of surgical interventions, in combination with an expanding number of resections in patients with compromised liver function, still results in an incidence of postresectional liver failure (PLF) of 1-9%. Preventive measures aim to enhance future remnant liver size and function. Numerous non-invasive techniques to assess liver function and predict remnant liver volume are being developed, along with introduction of novel surgical strategies that augment growth of the future remnant liver. Detection of PLF is often too late and treatment is primarily symptomatic. Current therapeutic research focuses on ([bio]artificial) liver function support and regenerative medicine. In this review we discuss the current state and new developments in prediction, prevention and management of PLF, in light of novel insights into the aetiology of this complex syndrome.

  9. A simple nonlocal damage model for predicting failure of notched laminates

    NASA Technical Reports Server (NTRS)

    Kennedy, T. C.; Nahan, M. F.

    1995-01-01

    The ability to predict failure loads in notched composite laminates is a requirement in a variety of structural design circumstances. A complicating factor is the development of a zone of damaged material around the notch tip. The objective of this study was to develop a computational technique that simulates progressive damage growth around a notch in a manner that allows the prediction of failure over a wide range of notch sizes. This was accomplished through the use of a relatively simple, nonlocal damage model that incorporates strain-softening. This model was implemented in a two-dimensional finite element program. Calculations were performed for two different laminates with various notch sizes under tensile loading, and the calculations were found to correlate well with experimental results.

  10. Benefits of Immediate Extubation Following Free Tissue Transfer for Head and Neck Reconstruction.

    PubMed

    Tamplen, Matthew L; Ricceri, Santo; Hemmat, Shirin; Seth, Rahul; Ryan, William R; Knott, P Daniel

    2016-09-01

    Background Immediate postprocedure extubation (cessation of mechanical ventilation) after free tissue transfer for head and neck reconstruction may improve outcomes, reduce intensive care unit and hospital length of stay, and reduce overall cost compared with delayed extubation in the intensive care unit. Methods Medical records of 180 consecutive patients undergoing free tissue transfer for head and neck reconstruction were reviewed. Patients immediately extubated in the operating room (immediate group, N = 63) were compared with patients who were extubated in the intensive care unit (delayed group, N = 117) by univariate and multivariate analysis. Results Medical complication rates and intensive care unit length of stay were significantly higher in the delayed extubation group (55.5 vs. 12.7%, p < 0.001, and 4.4 vs. 2.9 days, p < 0.001, respectively). Although the rate of preoperative alcohol use was similar between the two groups, significantly fewer patients underwent treatment for alcohol withdrawal or agitation in the immediate extubation group (3.2 vs. 27.4%, p = 0.001). There were no significant differences in surgical complication rates. Conclusion Immediate postprocedure extubation is associated with shorter intensive care unit length of stay, reduced medical complications, and reduced incidence of treatment for agitation/alcohol withdrawal for patients undergoing free tissue transfer for head and neck reconstruction.

  11. Post-extubation stridor in Respiratory Syncytial Virus bronchiolitis: Is there a role for prophylactic dexamethasone?

    PubMed Central

    Kappen, Teus H.; Calis, Job C.; van Woensel, Job; Raymakers-Janssen, Paulien A. M.; Bont, Louis J.; Hennus, Marije P.

    2017-01-01

    Aim The purpose of this study was to determine the incidence of reintubation due to upper airway obstruction in a homogeneous group of ventilated infants with Respiratory Syncytial Virus bronchiolitis. Our secondary objective was to determine whether prophylactic administration of dexamethasone prior to extubation was associated with decreased risk of reintubation. Methods This retrospective observational study in two Pediatric Intensive Care Units in 2 university hospitals in The Netherlands included two hundred patients younger than 13 months admitted with respiratory insufficiency caused by Respiratory Syncytial Virus bronchiolitis, requiring invasive mechanical ventilation. A logistic regression analysis with propensity score method was used to adjust for possible confounding. Results Reintubation due to post-extubation stridor occurred in 17 (8.5%) of 200 patients. After propensity score matching, administration of dexamethasone prior to extubation was associated with a significantly (p = 0.0011) decreased risk of reintubation due to post-extubation stridor compared to patients not receiving prophylactic dexamethasone (absolute risk reduction 13%, 95% CI 5.3–21%). Conclusion Reintubation due to post-extubation stridor is an important complication of ventilation for Respiratory Syncytial Virus bronchiolitis. Dexamethasone administered prior to extubation probably reduces the risk of post-extubation stridor necessitating reintubation in these infants. The results of this study support initiation of a placebo-controlled trial to confirm the beneficial effect of prophylactic dexamethasone. PMID:28207796

  12. A cellular solid criterion for predicting the axial-shear failure properties of bovine trabecular bone.

    PubMed

    Fenech, C M; Keaveny, T M

    1999-08-01

    In a long-term effort to develop a complete multi-axial failure criterion for human trabecular bone, the overall goal of this study was to compare the ability of a simple cellular solid mechanistic criterion versus the Tsai-Wu, Principal Strain, and von Mises phenomenological criteria--all normalized to minimize effects of interspecimen heterogeneity of strength--to predict the on-axis axial-shear failure properties of bovine trabecular bone. The Cellular Solid criterion that was developed here assumed that vertical trabeculae failed due to a linear superposition of axial compression/tension and bending stresses, induced by the apparent level axial and shear loading, respectively. Twenty-seven bovine tibial trabecular bone specimens were destructively tested on-axis without end artifacts, loaded either in combined tension-torsion (n = 10), compression-torsion (n = 11), or uniaxially (n = 6). For compression-shear, the mean (+/- S.D.) percentage errors between measured values and criterion predictions were 7.7 +/- 12.6 percent, 19.7 +/- 23.2 percent, 22.8 +/- 18.9 percent, and 82.4 +/- 64.5 percent for the Cellular Solid, Tsai-Wu, Principal Strain, and von Mises criteria, respectively; corresponding mean errors for tension-shear were -5.2 +/- 11.8 percent, 14.3 +/- 12.5 percent, 6.9 +/- 7.6 percent, and 57.7 +/- 46.3 percent. Statistical analysis indicated that the Cellular Solid criterion was the best performer for compression-shear, and performed as well as the Principal Strain criterion for tension-shear. These data should substantially improve the ability to predict axial-shear failure of dense trabecular bone. More importantly, the results firmly establish the importance of cellular solid analysis for understanding and predicting the multiaxial failure behavior of trabecular bone.

  13. Effect and clinical prediction of worsening renal function in acute decompensated heart failure.

    PubMed

    Breidthardt, Tobias; Socrates, Thenral; Noveanu, Markus; Klima, Theresia; Heinisch, Corinna; Reichlin, Tobias; Potocki, Mihael; Nowak, Albina; Tschung, Christopher; Arenja, Nisha; Bingisser, Roland; Mueller, Christian

    2011-03-01

    We aimed to establish the prevalence and effect of worsening renal function (WRF) on survival among patients with acute decompensated heart failure. Furthermore, we sought to establish a risk score for the prediction of WRF and externally validate the previously established Forman risk score. A total of 657 consecutive patients with acute decompensated heart failure presenting to the emergency department and undergoing serial creatinine measurements were enrolled. The potential of the clinical parameters at admission to predict WRF was assessed as the primary end point. The secondary end point was all-cause mortality at 360 days. Of the 657 patients, 136 (21%) developed WRF, and 220 patients had died during the first year. WRF was more common in the nonsurvivors (30% vs 41%, p = 0.03). Multivariate regression analysis found WRF to independently predict mortality (hazard ratio 1.92, p <0.01). In a single parameter model, previously diagnosed chronic kidney disease was the only independent predictor of WRF and achieved an area under the receiver operating characteristic curve of 0.60. After the inclusion of the blood gas analysis parameters into the model history of chronic kidney disease (hazard ratio 2.13, p = 0.03), outpatient diuretics (hazard ratio 5.75, p <0.01), and bicarbonate (hazard ratio 0.91, p <0.01) were all predictive of WRF. A risk score was developed using these predictors. On receiver operating characteristic curve analysis, the Forman and Basel prediction rules achieved an area under the curve of 0.65 and 0.71, respectively. In conclusion, WRF was common in patients with acute decompensated heart failure and was linked to significantly worse outcomes. However, the clinical parameters failed to adequately predict its occurrence, making a tailored therapy approach impossible.

  14. Hybrid neural intelligent system to predict business failure in small-to-medium-size enterprises.

    PubMed

    Borrajo, M Lourdes; Baruque, Bruno; Corchado, Emilio; Bajo, Javier; Corchado, Juan M

    2011-08-01

    During the last years there has been a growing need of developing innovative tools that can help small to medium sized enterprises to predict business failure as well as financial crisis. In this study we present a novel hybrid intelligent system aimed at monitoring the modus operandi of the companies and predicting possible failures. This system is implemented by means of a neural-based multi-agent system that models the different actors of the companies as agents. The core of the multi-agent system is a type of agent that incorporates a case-based reasoning system and automates the business control process and failure prediction. The stages of the case-based reasoning system are implemented by means of web services: the retrieval stage uses an innovative weighted voting summarization of self-organizing maps ensembles-based method and the reuse stage is implemented by means of a radial basis function neural network. An initial prototype was developed and the results obtained related to small and medium enterprises in a real scenario are presented.

  15. Tension Strength, Failure Prediction and Damage Mechanisms in 2D Triaxial Braided Composites with Notch

    NASA Technical Reports Server (NTRS)

    Norman, Timothy L.; Anglin, Colin

    1995-01-01

    The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to 2D triaxial braided textile composite materials. Four different fiber architectures were considered; braid angle, yarn and braider size, percentage of longitudinal yarns and braider angle varied. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yarn cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch strain between textile and tape equivalents could be detected for small braid angle, but the correlations were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

  16. Baroreflex sensitivity might predict responders to milrinone in patients with heart failure.

    PubMed

    Kishi, Takuya; Sunagawa, Kenji

    2010-01-01

    The phosphodiesterase III inhibitor milrinone (MIL) is considered to be effective for "wet and cold" heart failure. In some cases, however, the inotropic effects of milrinone are insufficient. A previous study suggested that baroreflex sensitivity (BRS) predicts the cases in which MIL increases left ventricular dp/dt. The aim of this study was to determine whether BRS measured using the spontaneous sequence method predicts the MIL responders. Twenty-four patients with "wet and cold" heart failure whose systolic blood pressure > 100 mmHg were enrolled. At 2 hours MIL improved dys-pnea, general fatigue, urine volume, and tricuspid regurgitant pressure gradient in 13 patients (responders; R group), whereas it failed to improve in 11 patients (nonresponders; NR group). BRS in the R group was significantly higher than that in the NR group prior to the MIL infusion. At 2 hours after the MIL infusion, BRS was further increased in the R group, but did not increase in the NR group. The sensitivity and specificity of BRS at a cut-off level of 5 ms/mmHg for the prediction of R group were 0.94 and 0.93, respectively. BRS might be useful for identifying potential responders to milrinone in patients with blood pressure-preserved "wet and cold" heart failure.

  17. Failure of Tube Models to Predict the Linear Rheology of Star/Linear Blends

    NASA Astrophysics Data System (ADS)

    Hall, Ryan; Desai, Priyanka; Kang, Beomgoo; Katzarova, Maria; Huang, Qifan; Lee, Sanghoon; Chang, Taihyun; Venerus, David; Mays, Jimmy; Schieber, Jay; Larson, Ronald

    We compare predictions of two of the most advanced versions of the tube model, namely the Hierarchical model by Wang et al. (J. Rheol. 54:223, 2010) and the BOB (branch-on-branch) model by Das et al. (J. Rheol. 50:207-234, 2006), against linear viscoelastic data on blends of monodisperse star and monodisperse linear polybutadiene polymers. The star was carefully synthesized/characterized by temperature gradient interaction chromatography, and rheological data in the high frequency region were obtained through time-temperature superposition. We found massive failures of both the Hierarchical and BOB models to predict the terminal relaxation behavior of the star/linear blends, despite their success in predicting the rheology of the pure star and pure linear. This failure occurred regardless of the choices made concerning constraint release, such as assuming arm retraction in fat or skinny tubes, or allowing for disentanglement relaxation to cut off the constraint release Rouse process at long times. The failures call into question whether constraint release can be described as a combination of constraint release Rouse processes and dynamic tube dilation within a canonical tube model of entanglement interactions.

  18. A Predictive Safety Management System Software Package Based on the Continuous Hazard Tracking and Failure Prediction Methodology

    NASA Technical Reports Server (NTRS)

    Quintana, Rolando

    2003-01-01

    The goal of this research was to integrate a previously validated and reliable safety model, called Continuous Hazard Tracking and Failure Prediction Methodology (CHTFPM), into a software application. This led to the development of a safety management information system (PSMIS). This means that the theory or principles of the CHTFPM were incorporated in a software package; hence, the PSMIS is referred to as CHTFPM management information system (CHTFPM MIS). The purpose of the PSMIS is to reduce the time and manpower required to perform predictive studies as well as to facilitate the handling of enormous quantities of information in this type of studies. The CHTFPM theory encompasses the philosophy of looking at the concept of safety engineering from a new perspective: from a proactive, than a reactive, viewpoint. That is, corrective measures are taken before a problem instead of after it happened. That is why the CHTFPM is a predictive safety because it foresees or anticipates accidents, system failures and unacceptable risks; therefore, corrective action can be taken in order to prevent all these unwanted issues. Consequently, safety and reliability of systems or processes can be further improved by taking proactive and timely corrective actions.

  19. Development of A Tabulated Thermo-Viscoplastic Material Model with Regularized Failure for Dynamic Ductile Failure Prediction of Structures under Impact Loading

    NASA Astrophysics Data System (ADS)

    Buyuk, Murat

    It is important to understand the dynamic failure behavior of structures subjected to impact loading in order to improve the survivability. Materials under impact are utterly affected by large deformations, high strain-rates, temperature softening and varying stress-states, which finally may lead to failure. It is shown that the impact characteristics are prone to change with several independent factors such as; impact speed, material thickness, and shape and orientation of the impacting object. Validated numerical simulations of impact tests reveal that the failure on ductile metals occur at certain locations of the failure locus that is constructed on a space as a function of all three stress invariants, which indicates that the failure depends profoundly on the state-of-stress. It is shown that existing material models are not always successful enough to cover the whole range of the failure locus and predict the failure. Therefore, it is a common practice to use different sets of material model parameters tuned or calibrated to cover a specific region of the failure loci in an ad hoc manner for practical reasons to match particular test results. Even in that case, specially tuned material properties are not capable of predicting these limited cases if differences in the mesh size and pattern need to be considered. In this dissertation a new, generic, thermo-elastic/viscoplastic material model with regularized failure is introduced. The new material model is implemented into a non-linear, explicit dynamics finite element code, LS-DYNA. A von Mises type isotropic, isochoric plasticity is utilized, where isotropic hardening, strain-rate hardening and temperature softening is considered. The model takes adiabatic heating and softening into account due to the plastic work. The constitutive relation is coupled with a new regularized accumulated failure law that is specifically developed to cover a large extent of the failure locus as a function of state

  20. Predicting Ductility and Failure Modes of TRIP Steels under Different Loading Conditions

    SciTech Connect

    Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2010-06-12

    We study the ultimate ductility and failure modes of a TRIP (TRansformation-Induced Plasticity) 800 steel under different loading conditions with an advanced micromechanics-based finite element analysis. The representative volume element (RVE) for the TRIP800 under examination is developed based on an actual microstructure obtained from scanning electron microscopy (SEM). The evolution of retained austenite during deformation process and the mechanical properties of the constituent phases of the TRIP800 steel are obtained from the synchrotron-based in-situ high-energy X-ray diffraction (HEXRD) experiments and a self-consistent (SC) model. The ductile failure of the TRIP800 under different loading conditions is predicted in the form of plastic strain localization without any prescribed failure criteria for the individual phases. Comparisons of the computational results with experimental measurements suggest that the microstructure-based finite element analysis can well capture the overall macroscopic behavior of the TRIP800 steel under different loading conditions. The methodology described in this study may be extended for studying the ultimate ductile failure mechanisms of TRIP steels as well as the effects of the various processing parameters on the macroscopic behaviors of TRIP steels.

  1. The Effect of Delamination on Damage Path and Failure Load Prediction for Notched Composite Laminates

    NASA Technical Reports Server (NTRS)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Chunchu, Prasad B.

    2007-01-01

    The influence of delamination on the progressing damage path and initial failure load in composite laminates is investigated. Results are presented from a numerical and an experimental study of center-notched tensile-loaded coupons. The numerical study includes two approaches. The first approach considers only intralaminar (fiber breakage and matrix cracking) damage modes in calculating the progression of the damage path. In the second approach, the model is extended to consider the effect of interlaminar (delamination) damage modes in addition to the intralaminar damage modes. The intralaminar damage is modeled using progressive damage analysis (PDA) methodology implemented with the VUMAT subroutine in the ABAQUS finite element code. The interlaminar damage mode has been simulated using cohesive elements in ABAQUS. In the experimental study, 2-3 specimens each of two different stacking sequences of center-notched laminates are tensile loaded. The numerical results from the two different modeling approaches are compared with each other and the experimentally observed results for both laminate types. The comparisons reveal that the second modeling approach, where the delamination damage mode is included together with the intralaminar damage modes, better simulates the experimentally observed damage modes and damage paths, which were characterized by splitting failures perpendicular to the notch tips in one or more layers. Additionally, the inclusion of the delamination mode resulted in a better prediction of the loads at which the failure took place, which were higher than those predicted by the first modeling approach which did not include delaminations.

  2. Predicting in vivo failure of pseudoelastic NiTi devices under low cycle, high amplitude fatigue.

    PubMed

    Young, Jeremy M; Van Vliet, Krystyn J

    2005-01-15

    Due to the large reversible strains achievable through the stress-induced austenite-martensite phase transformation in NiTi alloys, NiTi has replaced stainless steel in the majority of large-strain biomedical applications such as root canal enlargement. However, the pseudoelasticity of NiTi is currently overshadowed by the short fatigue life of NiTi wires used in this low cycle (200-2000 rpm), high amplitude (epsilon(a) > 2.5%) application, resulting in in vivo fracture or premature retirement of otherwise reusable NiTi-based wire devices. In this study, the failure of pseudoelastic 55.8 wt % Ni-Ti wire is investigated experimentally, as a function of experimental parameters that include the clinically relevant regime. The effects of radius of curvature, angle of curvature, wire diameter, strain amplitude, cyclic frequency, volume under strain, and specific heat of the surrounding environmental fluid are considered systematically. These data indicate that the lifetime or cycles to failure N(f) of a rotating NiTi wire can be predicted via a modified Coffin-Manson relation that is a strong function of both strain amplitude and volume under strain, and a weaker function of frequency and fluid specific heat. The resulting quantitative relation can be used to predict useful device lifetime under clinically relevant conditions and thereby reduce incidences of in vivo failure.

  3. No site unseen: predicting the failure to control problematic Internet use among young adults.

    PubMed

    Yamada, Tetsuhiro; Moshier, Samantha J; Otto, Michael W

    2016-11-01

    Problematic Internet use has been associated with the neglect of valued activities such as work, exercise, social activities, and relationships. In the present study, we expanded the understanding of problematic Internet use by identifying an important predictor of the inability to curb Internet use despite the desire to do so. Specifically, in a college student sample reporting a mean of 27.8 h of recreational Internet use in the past week, we investigated the role of distress intolerance (DI)-an individual difference variable that refers to the inability of an individual to tolerate emotional discomfort and to engage in goal-directed behavior when distressed-to predict the failure to meet personal restrictions on Internet use. Consistent with hypotheses, DI emerged as a significant predictor of the failure to meet self-control goals in both bivariate and multivariate models, indicating that DI offers unique prediction of self-control failure with problematic Internet use. Given that DI is a modifiable trait, these results encourage consideration of DI-focused early intervention strategies.

  4. A Triaxial Failure Diagram to predict the forming limit of 3D sheet metal parts subjected to multiaxial stresses

    NASA Astrophysics Data System (ADS)

    Rastellini, F.; Socorro, G.; Forgas, A.; Onate, E.

    2016-08-01

    Accurate prediction of failure and forming limits is essential when modelling sheet metal forming processes. Since traditional Forming Limit Curves (FLCs) are not valid for materials subjected to triaxial loading, a new failure criterion is proposed in this paper based on the stress triaxility and the effective plastic strain accumulated during the history of material loading. Formability zones are identified inside the proposed Triaxial Failure Diagram (TFD). FLCs may be mapped into the TFD defining a new Triaxial Failure Curve, or it can be defined by triaxial failure experiments. Several TFD examples are validated and constrasted showing acceptable accuracy in the numerical prediction of forming failure/limit of 3D thick sheet parts.

  5. An endometrial gene expression signature accurately predicts recurrent implantation failure after IVF

    PubMed Central

    Koot, Yvonne E. M.; van Hooff, Sander R.; Boomsma, Carolien M.; van Leenen, Dik; Groot Koerkamp, Marian J. A.; Goddijn, Mariëtte; Eijkemans, Marinus J. C.; Fauser, Bart C. J. M.; Holstege, Frank C. P.; Macklon, Nick S.

    2016-01-01

    The primary limiting factor for effective IVF treatment is successful embryo implantation. Recurrent implantation failure (RIF) is a condition whereby couples fail to achieve pregnancy despite consecutive embryo transfers. Here we describe the collection of gene expression profiles from mid-luteal phase endometrial biopsies (n = 115) from women experiencing RIF and healthy controls. Using a signature discovery set (n = 81) we identify a signature containing 303 genes predictive of RIF. Independent validation in 34 samples shows that the gene signature predicts RIF with 100% positive predictive value (PPV). The strength of the RIF associated expression signature also stratifies RIF patients into distinct groups with different subsequent implantation success rates. Exploration of the expression changes suggests that RIF is primarily associated with reduced cellular proliferation. The gene signature will be of value in counselling and guiding further treatment of women who fail to conceive upon IVF and suggests new avenues for developing intervention. PMID:26797113

  6. NASA Langley developments in response calculations needed for failure and life prediction

    NASA Astrophysics Data System (ADS)

    Housner, Jerrold M.

    1993-10-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  7. NASA Langley developments in response calculations needed for failure and life prediction

    NASA Technical Reports Server (NTRS)

    Housner, Jerrold M.

    1993-01-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  8. Risk Analysis of the Space Shuttle: Pre-Challenger Bayeisan Prediction of Failure

    SciTech Connect

    Dana L. Kelly

    2008-02-01

    Dalal et al performed a statistical analysis of field and nozzle O-ring data collected prior to the ill-fated launch of the Challenger in January 1986. The purpose of their analysis was to show how statistical analysis could be used to provide information to decisionmakers prior to the launch, information that could have been expected to lead to a decision to abort the launch due to the low temperatures (~30o F.) present at the launch pad on the morning of the scheduled launch. Dalal et al. performed a frequentist analysis of the O-ring data, and found that a logistic regression model provided a relatively good fit to the past data. In the second portion of their paper, Dalal et al. propagated parameter uncertainties through the fitted logistic regression model in order to estimate the probability of shuttle failure due to O-ring failure at the estimated launch temperature of ~30o F. Because their analysis was frequentist in nature, probability distributions representing epistemic uncertainty in the input parameters were not available, and the authors had to resort to an approximate approach based on bootstrap confidence intervals. In this paper, we will re-evaluate the analyses of Dalal et al. from a Bayesian perspective. Markov chain Monte Carlo (MCMC) sampling will be used to sample from the joint posterior distribution of the model parameters, and to sample from the posterior predictive distributions at the estimated launch temperature, a temperature that had not been observed in prior launches of the space shuttle. Uncertainties, which are represented by probability distributions in the Bayesian approach, are propagated through the model to obtain a probability distribution for O-ring failure, and subsequently for shuttle failure as a result of O-ring failure. No approximations are required in the Bayesian approach and the resulting distributions can be input to a decision analysis to obtain expected utility for the decision to launch.

  9. Does extubation result in haemodynamic instability in patients following coronary artery bypass grafts?

    PubMed

    Walthall, H; Ray, S; Robson, D

    2001-10-01

    Coronary heart disease and its management continue to be at the centre of Government health policy. The present political climate demands clinical effectiveness and best practice should be established, while maintaining the philosophy of cost-effectiveness and resource management. These directives have led practitioners to question the care of patients following coronary artery bypass surgery, in particular the role of mechanical ventilation and the subsequent act of extubation. A retrospective study of 89 patients who had coronary artery bypass grafts (emergency and elective) was undertaken, to establish if extubation had a significant effect on the haemodynamic status of patients with variable degrees of left ventricular function (19% with poor left ventricular function). The study found that extubation was achieved within a mean time of 4.97 hours following return from surgery. Extubation resulted in a significant increase in heart rate (P = 0.001), as well as a respiratory acidosis (pCO2: P = 0.000; pH: P = 0.000). However, the stability of the patient was not compromised, with neither mean arterial blood pressure (P = 0.825) nor oxygenation levels (P = 0.267) being significantly altered by extubation. On multivariate analysis, the act of extubation had no significant effect on any of the dependent variables. These results suggest that it is not extubation alone that has an impact on the haemodynamic stability of patients following coronary artery bypass grafts, but that this is indeed multifactorial. Therefore extubation is 'safe' practice for patients with varying degrees of left ventricular function following coronary artery bypass grafts. Limitations of the study are acknowledged.

  10. Prediction of survival in patients with cardiogenic shock and multiorgan failure treated with biventricular assist device.

    PubMed

    Potapov, Evgenij V; Stepanenko, Alexander; Kukucka, Marian; Ba Fadhl, Faiz H; Qedra, Naser; Weng, Yuguo; Pasic, Miralem; Lehmkuhl, Hans B; Krabatsch, Thomas; Hetzer, Roland

    2010-01-01

    Mechanical circulatory support (MCS) is valuable in saving the lives of patients with severe cardiogenic shock. However, their survival is limited if multiorgan failure (MOF) proves to be irreversible. Although ventricular assist devices (VADs) have been shown to reverse end-organ failure in some patients, the pathophysiological mechanisms of end-organ failure and its regression are not fully understood, and clinical markers and thresholds for the "point of no return" are lacking. We investigated predictors of 30-day survival in patients supported with a biventricular assist device (BVAD). We studied 157 patients implanted with a Berlin Heart EXCOR BVAD between 1987 and 2006. Children younger than 10 years and cases with postcardiotomy syndrome and transplant failure were excluded from the analysis as well as patients with technical or bleeding problems requiring rethoracotomy. In total, 69 clinical, hemodynamic, echocardiographic, and laboratory parameters were evaluated. Most of the patients suffered from ischemic cardiomyopathy or acute myocardial infarction. In addition, the preoperative multiple organ dysfunction syndrome (MODS) and the sequential organ failure assessment (SOFA) scores were calculated. The patients were divided into two groups regarding procedural success: group I-survival >30 days or heart transplantation or weaning from device (n = 105) and group II-death on system <30 days after surgery (n = 52). The 30-day procedural success rate was 67%. The patients in group I had higher systolic blood pressure (96.7 vs. 90.1 mm Hg, p = 0.027), lower serum creatinine (1.96 vs. 2.4 mg/dl, p = 0.001), and higher arterial pH (7.43 vs. 7.37, p = 0.02). The multivariate analysis recognized age, body temperature, systolic blood pressure, MODS score, and higher arterial pH as significant predictors for 30-day mortality. Standard markers for severity of cardiogenic shock and MOF do not predict survival on BVAD. As expected, older patients are at higher risk for

  11. Prediction of success and failure of behavior modification as treatment for dental anxiety.

    PubMed

    Eli, I; Baht, R; Blacher, S

    2004-08-01

    Behavior modification techniques are effective in the treatment of extreme dental anxiety, but their success is by no means absolute. In the present article, the Corah Dental Anxiety Scale (DAS), the self-report symptom inventory SCL-90R and a questionnaire accessing subjects' daydreaming styles (the Short Imaginal Process Inventory) were used to develop possible predictive measures for success and failure of behavior modification as a treatment for dental fear. The patients' level of distractibility and mind wandering, initial dental anxiety and somatization significantly predicted the success of therapy. The odds ratio indicated that the risk of therapy failure increased about 11 times with an increase of one scale of the Poor Attention Control Scale, about three times with an increase of one level of the mean DAS score, and 0.17 times with an increase of one level of somatization. The predictive value of the chosen scales was 80%. Thus, the use of these scales as part of an initial admittance process for patients who suffer from dental anxiety can enhance our ability to better recognize patients who are prone to fail behavior therapy as treatment for their problem, and enable their referral for other possible modes of treatment.

  12. Predicting failure using conditioning on damage history: Demonstration on percolation and hierarchical fiber bundles

    SciTech Connect

    Andersen, J.V.; Sornette, D.

    2005-11-01

    We formulate the problem of probabilistic predictions of global failure in the simplest possible model based on site percolation and on one of the simplest models of time-dependent rupture, a hierarchical fiber bundle model. We show that conditioning the predictions on the knowledge of the current degree of damage (occupancy density p or number and size of cracks) and on some information on the largest cluster improves significantly the prediction accuracy, in particular by allowing one to identify those realizations which have anomalously low or large clusters (cracks). We quantify the prediction gains using two measures, the relative specific information gain (which is the variation of entropy obtained by adding new information) and the root mean square of the prediction errors over a large ensemble of realizations. The bulk of our simulations have been obtained with the two-dimensional site percolation model on a lattice of size LxL=20x20 and hold true for other lattice sizes. For the hierarchical fiber bundle model, conditioning the measures of damage on the information of the location and size of the largest crack extends significantly the critical region and the prediction skills. These examples illustrate how ongoing damage can be used as a revelation of both the realization-dependent preexisting heterogeneity and the damage scenario undertaken by each specific sample.

  13. A standardized model for predicting flap failure using indocyanine green dye

    NASA Astrophysics Data System (ADS)

    Zimmermann, Terence M.; Moore, Lindsay S.; Warram, Jason M.; Greene, Benjamin J.; Nakhmani, Arie; Korb, Melissa L.; Rosenthal, Eben L.

    2016-03-01

    Techniques that provide a non-invasive method for evaluation of intraoperative skin flap perfusion are currently available but underutilized. We hypothesize that intraoperative vascular imaging can be used to reliably assess skin flap perfusion and elucidate areas of future necrosis by means of a standardized critical perfusion threshold. Five animal groups (negative controls, n=4; positive controls, n=5; chemotherapy group, n=5; radiation group, n=5; chemoradiation group, n=5) underwent pre-flap treatments two weeks prior to undergoing random pattern dorsal fasciocutaneous flaps with a length to width ratio of 2:1 (3 x 1.5 cm). Flap perfusion was assessed via laser-assisted indocyanine green dye angiography and compared to standard clinical assessment for predictive accuracy of flap necrosis. For estimating flap-failure, clinical prediction achieved a sensitivity of 79.3% and a specificity of 90.5%. When average flap perfusion was more than three standard deviations below the average flap perfusion for the negative control group at the time of the flap procedure (144.3+/-17.05 absolute perfusion units), laser-assisted indocyanine green dye angiography achieved a sensitivity of 81.1% and a specificity of 97.3%. When absolute perfusion units were seven standard deviations below the average flap perfusion for the negative control group, specificity of necrosis prediction was 100%. Quantitative absolute perfusion units can improve specificity for intraoperative prediction of viable tissue. Using this strategy, a positive predictive threshold of flap failure can be standardized for clinical use.

  14. A model for predicting high-temperature fatigue failure of a W/Cu composite

    NASA Technical Reports Server (NTRS)

    Verrilli, M. J.; Kim, Y.-S.; Gabb, T. P.

    1991-01-01

    The material studied, a tungsten-fiber-reinforced, copper-matrix composite, is a candidate material for rocket nozzle liner applications. It was shown that at high temperatures, fatigue cracks initiate and propagate inside the copper matrix through a process of initiation, growth, and coalescence of grain boundary cavities. The ductile tungsten fibers neck and rupture locally after the surrounding matrix fails, and complete failure of the composite then ensues. A simple fatigue life prediction model is presented for the tungsten/copper composite system.

  15. Progressive failure methodologies for predicting residual strength and life of laminated composites

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Allen, David H.; Obrien, T. Kevin

    1991-01-01

    Two progressive failure methodologies currently under development by the Mechanics of Materials Branch at NASA Langley Research Center are discussed. The damage tolerance/fail safety methodology developed by O'Brien is an engineering approach to ensuring adequate durability and damage tolerance by treating only delamination onset and the subsequent delamination accumulation through the laminate thickness. The continuum damage model developed by Allen and Harris employs continuum damage laws to predict laminate strength and life. The philosophy, mechanics framework, and current implementation status of each methodology are presented.

  16. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    PubMed Central

    Alani, Amir M.; Faramarzi, Asaad

    2015-01-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

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

    SciTech Connect

    Sakalaukus, Peter Joseph

    2015-08-01

    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.

  18. Slope Failure Prediction and Early Warning Awareness Education for Reducing Landslides Casualty in Malaysia

    NASA Astrophysics Data System (ADS)

    Koay, S. P.; Tay, L. T.; Fukuoka, H.; Koyama, T.; Sakai, N.; Jamaludin, S. B.; Lateh, H.

    2015-12-01

    Northeast monsoon causes heavy rain in east coast of Peninsular Malaysia from November to March, every year. During this monsoon period, besides the happening of flood along east coast, landslides also causes millions of Malaysian Ringgit economical losses. Hence, it is essential to study the prediction of slope failure to prevent the casualty of landslides happening. In our study, we introduce prediction method of the accumulated rainfall affecting the stability of the slope. If the curve, in the graph, which is presented by rainfall intensity versus accumulated rainfall, crosses over the critical line, the condition of the slope is considered in high risk where the data are calculated and sent from rain gauge in the site via internet. If the possibility of slope failure is going high, the alert message will be sent out to the authorities for decision making on road block or setting the warning light at the road side. Besides road block and warning light, we propose to disseminate short message, to pre-registered mobile phone user, to notify the public for easing the traffic jam and avoiding unnecessary public panic. Prediction is not enough to prevent the casualty. Early warning awareness of the public is very important to reduce the casualty of landslides happening. IT technology does not only play a main role in disseminating information, early warning awareness education, by using IT technology, should be conducted, in schools, to give early warning awareness on natural hazard since childhood. Knowing the pass history on landslides occurrence will gain experience on the landslides happening. Landslides historical events with coordinate information are stored in database. The public can browse these historical events via internet. By referring to such historical landslides events, the public may know where did landslides happen before and the possibility of slope failure occurrence again is considered high. Simulation of rainfall induced slope failure mechanism

  19. Can the theory of critical distances predict the failure of shape memory alloys?

    PubMed

    Kasiri, Saeid; Kelly, Daniel J; Taylor, David

    2011-06-01

    Components made from shape memory alloys (SMAs) such as nitinol often fail from stress concentrations and defects such as notches and cracks. It is shown here for the first time that these failures can be predicted using the theory of critical distances (TCDs), a method which has previously been used to study fracture and fatigue in other materials. The TCD uses the stress at a certain distance ahead of the notch to predict the failure of the material due to the stress concentration. The critical distance is believed to be a material property which is related to the microstructure of the material. The TCD is simply applied to a linear model of the material without the need to model the complication of its non-linear behaviour. The non-linear behaviour of the material at fracture is represented in the critical stress. The effect of notches and short cracks on the fracture of SMA NiTi was studied by analysing experimental data from the literature. Using a finite element model with elastic material behaviour, it is shown that the TCD can predict the effect of crack length and notch geometry on the critical stress and stress intensity for fracture, with prediction errors of less than 5%. The value of the critical distance obtained for this material was L = 90 μm; this may be related to its grain size. The effects of short cracks on stress intensity were studied. It was shown that the same value of the critical distance (L = 90 μm) could estimate the experimental data for both notches and short cracks.

  20. Diagnostic prediction of renal failure from blood serum analysis by FTIR spectrometry and chemometrics.

    PubMed

    Khanmohammadi, Mohammdreza; Ghasemi, Keyvan; Garmarudi, Amir Bagheri; Ramin, Mehdi

    2015-02-05

    A new diagnostic approach based on Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectrometry and classification algorithm has been introduced which provides a rapid, reliable, and easy way to perform blood test for the diagnosis of renal failure. Blood serum samples from 35 renal failure patients and 40 healthy persons were analyzed by ATR-FTIR spectrometry. The resulting data was processed by Quadratic Discriminant Analysis (QDA) and QDA combined with simple filtered method. Spectroscopic studies were performed in 900-2000cm(-)(1) spectral region with 3.85cm(-1) data space. Results showed 93.33% and 100% of accuracy for QDA and filter-QDA models, respectively. In the first step, 30 samples were applied to construct the model. In order to modify the capability of QDA in prediction of test samples, filter-based feature selection methods were applied. It was found that the filtered spectra coupled with QDA could correctly predict the test samples in most of the cases.

  1. Diagnostic prediction of renal failure from blood serum analysis by FTIR spectrometry and chemometrics

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Mohammdreza; Ghasemi, Keyvan; Garmarudi, Amir Bagheri; Ramin, Mehdi

    2015-02-01

    A new diagnostic approach based on Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectrometry and classification algorithm has been introduced which provides a rapid, reliable, and easy way to perform blood test for the diagnosis of renal failure. Blood serum samples from 35 renal failure patients and 40 healthy persons were analyzed by ATR-FTIR spectrometry. The resulting data was processed by Quadratic Discriminant Analysis (QDA) and QDA combined with simple filtered method. Spectroscopic studies were performed in 900-2000 cm-1 spectral region with 3.85 cm-1 data space. Results showed 93.33% and 100% of accuracy for QDA and filter-QDA models, respectively. In the first step, 30 samples were applied to construct the model. In order to modify the capability of QDA in prediction of test samples, filter-based feature selection methods were applied. It was found that the filtered spectra coupled with QDA could correctly predict the test samples in most of the cases.

  2. Application of a neural network as a potential aid in predicting NTF pump failure

    NASA Technical Reports Server (NTRS)

    Rogers, James L.; Hill, Jeffrey S.; Lamarsh, William J., II; Bradley, David E.

    1993-01-01

    The National Transonic Facility has three centrifugal multi-stage pumps to supply liquid nitrogen to the wind tunnel. Pump reliability is critical to facility operation and test capability. A highly desirable goal is to be able to detect a pump rotating component problem as early as possible during normal operation and avoid serious damage to other pump components. If a problem is detected before serious damage occurs, the repair cost and downtime could be reduced significantly. A neural network-based tool was developed for monitoring pump performance and aiding in predicting pump failure. Once trained, neural networks can rapidly process many combinations of input values other than those used for training to approximate previously unknown output values. This neural network was applied to establish relationships among the critical frequencies and aid in predicting failures. Training pairs were developed from frequency scans from typical tunnel operations. After training, various combinations of critical pump frequencies were propagated through the neural network. The approximated output was used to create a contour plot depicting the relationships of the input frequencies to the output pump frequency.

  3. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and facesheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  4. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. Fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a strength reduction of 10 percent due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  5. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas A.; Goyal, Vinay K.; Lundgren, Eric C.; Patel, Dhruv N.; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth N.

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  6. Methods for applying statistical penalties when predicting factors of safety using the Tsai-Wu failure criterion

    NASA Astrophysics Data System (ADS)

    Richardson, D. E.; Regl, R. R.; Iverson, M. P.; Phipps, B. E.

    1993-06-01

    Engineers are often required to estimate safety factors for structures using statistically based allowable stresses. Several approaches for making such estimations are possible. Commonly, the Tsai-Wu failure criterion is used for composite materials. If the quadratic failure criterion proposed by S.W. Tsai and E.M. Wu is used with statistically penalized allowable stress levels, unrealistic results are possible unless the penalties are assessed carefully. Some approaches used in calculating safety factors can predict that the statistically determined allowable stress levels are greater than mean failure levels. Other methods predict that, under severe conditions, the penalized failure surface does not circumscribe the origin (i.e., the unloaded state would not be allowed). It is therefore important that designers and analysts take care when choosing an approach for predicting safety factors using statistically penalized data.

  7. Rapid and Highly Accurate Prediction of Poor Loop Diuretic Natriuretic Response in Patients With Heart Failure

    PubMed Central

    Testani, Jeffrey M.; Hanberg, Jennifer S.; Cheng, Susan; Rao, Veena; Onyebeke, Chukwuma; Laur, Olga; Kula, Alexander; Chen, Michael; Wilson, F. Perry; Darlington, Andrew; Bellumkonda, Lavanya; Jacoby, Daniel; Tang, W. H. Wilson; Parikh, Chirag R.

    2015-01-01

    Background Removal of excess sodium and fluid is a primary therapeutic objective in acute decompensated heart failure (ADHF) and commonly monitored with fluid balance and weight loss. However, these parameters are frequently inaccurate or not collected and require a delay of several hours after diuretic administration before they are available. Accessible tools for rapid and accurate prediction of diuretic response are needed. Methods and Results Based on well-established renal physiologic principles an equation was derived to predict net sodium output using a spot urine sample obtained one or two hours following loop diuretic administration. This equation was then prospectively validated in 50 ADHF patients using meticulously obtained timed 6-hour urine collections to quantitate loop diuretic induced cumulative sodium output. Poor natriuretic response was defined as a cumulative sodium output of <50 mmol, a threshold that would result in a positive sodium balance with twice-daily diuretic dosing. Following a median dose of 3 mg (2–4 mg) of intravenous bumetanide, 40% of the population had a poor natriuretic response. The correlation between measured and predicted sodium output was excellent (r=0.91, p<0.0001). Poor natriuretic response could be accurately predicted with the sodium prediction equation (AUC=0.95, 95% CI 0.89–1.0, p<0.0001). Clinically recorded net fluid output had a weaker correlation (r=0.66, p<0.001) and lesser ability to predict poor natriuretic response (AUC=0.76, 95% CI 0.63–0.89, p=0.002). Conclusions In patients being treated for ADHF, poor natriuretic response can be predicted soon after diuretic administration with excellent accuracy using a spot urine sample. PMID:26721915

  8. Sufentanil infusion before extubation suppresses coughing on emergence without delaying extubation time and reduces postoperative analgesic requirement without increasing nausea and vomiting after desflurane anesthesia

    PubMed Central

    Lee, Jea Yeun; Lim, Byung Gun; Park, Hye Yoon

    2012-01-01

    Background Coughing, hypertension, tachycardia, and even laryngospasm can occur due to airway irritation during emergence from anesthesia. We investigated the effect of maintaining a sufentanil infusion during emergence from anesthesia by evaluating the incidence of cough and recovery profiles at extubation. Methods In total, eighty-four patients undergoing an elective laparoscopic hysterectomy were randomly divided into two sufentanil groups and a control group. During emergence, sufentanil was administered in the sufentanil groups at a rate of 0.2 µg/kg/hr (Group S1) or 0.3 µg/kg/hr (Group S2), and saline was administered to the control group. Cough score, hemodynamic changes, and recovery profiles, such as duration from skin closure to a bispectral index of 80, to eye opening at verbal command, to tracheal extubation and the total duration of study solution infusion, were recorded. The pain score, the total volume of administered patient-controlled analgesia (PCA), and the postoperative nausea and vomiting (PONV) score were evaluated 1, 6, and 24 hours after surgery. Results Groups S1 and S2 showed significantly lower cough scores and smaller hemodynamic changes on extubation compared to Group C. Recovery profiles showed no significant differences among the three groups. Pain score, PONV at 1 hour postoperatively, and the total volume of PCA administered at all evaluation times were significantly lower in Groups S1 and S2 than in the control group. However, pain score, and PONV at 6 hours and 24 hours postoperatively showed no significant differences. Conclusions A sufentanil infusion (0.2-0.3 µg/kg/hr) during emergence from desflurane anesthesia may suppress coughing on extubation in patients with body mass indexes (BMI) of 21-26 without delaying extubation time. It may also reduce the postoperative analgesic requirement without increasing PONV. PMID:22778885

  9. CrachFEM - A Comprehensive Approach For The Prediction Of Sheet Metal Failure

    SciTech Connect

    Dell, Harry; Gese, Helmut; Oberhofer, Gernot

    2007-05-17

    A correct prediction of a possible sheet metal failure is essential to sheet metal forming simulations. The use of the conventional forming limit curve (FLC) is the standard approach on industrial level for this problem. The FLC concept is limited to the case of linear strain paths, however. The initial FLC is no longer valid in the case of nonlinear strain paths. The algorithm Crach allows for a transient prediction of the forming limit for localized necking in the case of arbitrary strain paths. For high strength steels and aluminium sheets there is also a risk of fracture without prior localized necking. This paper presents a fracture model that accounts for ductile fracture (caused by void nucleation, void growth and void coalescence) and shear fracture (caused by shear band localization). For both types of fracture, stress state parameters are introduced which can be applied for the plane stress state and for the general 3D stress state. The fracture limits are defined by the equivalent plastic strain at fracture as a function of the stress state parameter based on different experiments with nearly constant stress state parameter. These fracture limit curves are a basis for an integral damage accumulation in the sheet metal forming simulation for arbitrary nonlinear strain paths. The model Crach for the prediction of localized necking and the two fracture models for ductile and shear fracture are combined in the comprehensive failure model CrachFEM. CrachFEM can be linked via a user material model MF GenYld to different explicit FEM codes.

  10. Postoperative Prostate-Specific Antigen Velocity Independently Predicts for Failure of Salvage Radiotherapy After Prostatectomy

    SciTech Connect

    King, Christopher R. Presti, Joseph C.; Brooks, James D.; Gill, Harcharan; Spiotto, Michael T.

    2008-04-01

    Purpose: Identification of patients most likely to benefit from salvage radiotherapy (RT) using postoperative (postop) prostate-specific antigen (PSA) kinetics. Methods and Materials: From 1984 to 2004, 81 patients who fit the following criteria formed the study population: undetectable PSA after radical prostatectomy (RP); pathologically negative nodes; biochemical relapse defined as a persistently detectable PSA; salvage RT; and two or more postop PSAs available before salvage RT. Salvage RT included the whole pelvic nodes in 55 patients and 4 months of total androgen suppression in 56 patients. The median follow-up was >5 years. All relapses were defined as a persistently detectable PSA. Kaplan-Meier and Cox proportional hazards multivariable analysis were performed for all clinical, pathological, and treatment factors predicting for biochemical relapse-free survival (bRFS). Results: There were 37 biochemical relapses observed after salvage RT. The 5-year bRFS after salvage RT for patients with postop prostate-specific antigen velocity {<=}1 vs. >1 ng/ml/yr was 59% vs. 29%, p = 0.002. In multivariate analysis, only postop PSAV (p = 0.0036), pre-RT PSA level {<=}1 (p = 0.037) and interval-to-relapse >10 months (p = 0.012) remained significant, whereas pelvic RT, hormone therapy, and RT dose showed a trend (p = {approx}0.06). PSAV, but not prostate-specific antigen doubling time, predicted successful salvage RT, suggesting an association of zero-order kinetics with locally recurrent disease. Conclusions: Postoperative PSA velocity independently predicts for the failure of salvage RT and can be considered in addition to high-risk features when selecting patients in need of systemic therapy following biochemical failure after RP. For well-selected patients, salvage RT can achieve high cure rates.

  11. The second Sandia Fracture Challenge. Predictions of ductile failure under quasi-static and moderate-rate dynamic loading

    DOE PAGES

    Boyce, B. L.; Kramer, S. L. B.; Bosiljevac, T. R.; ...

    2016-03-14

    Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the blind, quantitative predictive ability of simulation methods against a previously unseen failure problem. Instead of evaluating the predictions of a single simulation approach, the Sandia Fracture Challenge relied on numerous volunteer teams with expertise in computational mechanics to apply a broad range of computational methods, numerical algorithms, and constitutive modelsmore » to the challenge. This exercise is intended to evaluate the state of health of technologies available for failure prediction. In the first Sandia Fracture Challenge, a wide range of issues were raised in ductile failure modeling, including a lack of consistency in failure models, the importance of shear calibration data, and difficulties in quantifying the uncertainty of prediction [see Boyce et al. (Int J Fract 186:5–68, 2014) for details of these observations]. This second Sandia Fracture Challenge investigated the ductile rupture of a Ti–6Al–4V sheet under both quasi-static and modest-rate dynamic loading (failure in ~ 0.1 s). Like the previous challenge, the sheet had an unusual arrangement of notches and holes that added geometric complexity and fostered a competition between tensile- and shear-dominated failure modes. The teams were asked to predict the fracture path and quantitative far-field failure metrics such as the peak force and displacement to cause crack initiation. Fourteen teams contributed blind predictions, and the experimental outcomes were quantified in three independent test labs. In addition, shortcomings were revealed in this second challenge such as inconsistency in the application of appropriate boundary

  12. The second Sandia Fracture Challenge. Predictions of ductile failure under quasi-static and moderate-rate dynamic loading

    SciTech Connect

    Boyce, B. L.; Kramer, S. L. B.; Bosiljevac, T. R.; Corona, E.; Moore, J. A.; Elkhodary, K.; Simha, C. H. M.; Williams, B. W.; Cerrone, A. R.; Nonn, A.; Hochhalter, J. D.; Bomarito, G. F.; Warner, J. E.; Carter, B. J.; Warner, D. H.; Ingraffea, A. R.; Zhang, T.; Fang, X.; Lua, J.; Chiaruttini, V.; Mazière, M.; Feld-Payet, S.; Yastrebov, V. A.; Besson, J.; Chaboche, J. -L.; Lian, J.; Di, Y.; Wu, B.; Novokshanov, D.; Vajragupta, N.; Kucharczyk, P.; Brinnel, V.; Döbereiner, B.; Münstermann, S.; Neilsen, M. K.; Dion, K.; Karlson, K. N.; Foulk, J. W.; Brown, A. A.; Veilleux, M. G.; Bignell, J. L.; Sanborn, S. E.; Jones, C. A.; Mattie, P. D.; Pack, K.; Wierzbicki, T.; Chi, S. -W.; Lin, S. -P.; Mahdavi, A.; Predan, J.; Zadravec, J.; Gross, A. J.; Ravi-Chandar, K.; Xue, L.

    2016-03-14

    Ductile failure of structural metals is relevant to a wide range of engineering scenarios. Computational methods are employed to anticipate the critical conditions of failure, yet they sometimes provide inaccurate and misleading predictions. Challenge scenarios, such as the one presented in the current work, provide an opportunity to assess the blind, quantitative predictive ability of simulation methods against a previously unseen failure problem. Instead of evaluating the predictions of a single simulation approach, the Sandia Fracture Challenge relied on numerous volunteer teams with expertise in computational mechanics to apply a broad range of computational methods, numerical algorithms, and constitutive models to the challenge. This exercise is intended to evaluate the state of health of technologies available for failure prediction. In the first Sandia Fracture Challenge, a wide range of issues were raised in ductile failure modeling, including a lack of consistency in failure models, the importance of shear calibration data, and difficulties in quantifying the uncertainty of prediction [see Boyce et al. (Int J Fract 186:5–68, 2014) for details of these observations]. This second Sandia Fracture Challenge investigated the ductile rupture of a Ti–6Al–4V sheet under both quasi-static and modest-rate dynamic loading (failure in ~ 0.1 s). Like the previous challenge, the sheet had an unusual arrangement of notches and holes that added geometric complexity and fostered a competition between tensile- and shear-dominated failure modes. The teams were asked to predict the fracture path and quantitative far-field failure metrics such as the peak force and displacement to cause crack initiation. Fourteen teams contributed blind predictions, and the experimental outcomes were quantified in three independent test labs. In addition, shortcomings were revealed in this second challenge such as inconsistency in the application of appropriate boundary conditions, need

  13. In Nonagenarians, Acute Kidney Injury Predicts In-Hospital Mortality, while Heart Failure Predicts Hospital Length of Stay

    PubMed Central

    Chao, Chia-Ter; Lin, Yu-Feng; Tsai, Hung-Bin; Hsu, Nin-Chieh; Tseng, Chia-Lin; Ko, Wen-Je

    2013-01-01

    Background/Aims The elderly constitute an increasing proportion of admitted patients worldwide. We investigate the determinants of hospital length of stay and outcomes in patients aged 90 years and older. Methods We retrospectively analyzed all admitted patients aged >90 years from the general medical wards in a tertiary referral medical center between August 31, 2009 and August 31, 2012. Patients’ clinical characteristics, admission diagnosis, concomitant illnesses at admission, and discharge diagnosis were collected. Each patient was followed until discharge or death. Multivariate logistic regression analysis was utilized to study factors associated with longer hospital length of stay (>7 days) and in-hospital mortality. Results A total of 283 nonagenarian in-patients were recruited, with 118 (41.7%) hospitalized longer than one week. Nonagenarians admitted with pneumonia (p = 0.04) and those with lower Barthel Index (p = 0.012) were more likely to be hospitalized longer than one week. Multivariate logistic regression analysis revealed that patients with lower Barthel Index (odds ratio [OR] 0.98; p = 0.021) and those with heart failure (OR 3.05; p = 0.046) had hospital stays >7 days, while patients with lower Barthel Index (OR 0.93; p = 0.005), main admission nephrologic diagnosis (OR 4.83; p = 0.016) or acute kidney injury (OR 30.7; p = 0.007) had higher in-hospital mortality. Conclusion In nonagenarians, presence of heart failure at admission was associated with longer hospital length of stay, while acute kidney injury at admission predicted higher hospitalization mortality. Poorer functional status was associated with both prolonged admission and higher in-hospital mortality. PMID:24223127

  14. Model for end-stage liver disease predicts right ventricular failure in patients with left ventricular assist devices.

    PubMed

    Yost, Gardner L; Coyle, Laura; Bhat, Geetha; Tatooles, Antone J

    2016-03-01

    High rates of right ventricular failure continue to affect postoperative outcomes in patients implanted with left ventricular assist devices (LVADs). Development of right ventricular failure and implantation with right ventricular assist devices is known to be associated with significantly increased mortality. The model for end-stage liver disease (MELD) score is an effective means of evaluating liver dysfunction. We investigated the prognostic utility of postoperative MELD on post-LVAD implantation outcomes. MELD scores, demographic data, and outcomes including length of stay, survival, and postoperative right ventricular failure were collected for 256 patients implanted with continuous flow LVADs. Regression and Kaplan-Meier analyses were used to investigate the relationship between MELD and all outcomes. Increased MELD score was found to be an independent predictor of both right heart failure and necessity for RVAD implantation (OR 1.097, CI 1.040-1.158, p = 0.001; OR 1.121, CI 1.015, p = 0.024, respectively). Patients with RV failure and who underwent RVAD implantation had reduced postoperative survival compared to patients with RV dysfunction (no RV failure = 651.4 ± 609.8 days, RV failure = 392.6 ± 444.8 days, RVAD = 89.3 ± 72.8 days; p < 0.001). In conclusion, MELD can be used to reliably predict postoperative right heart failure and the necessity for RVAD implantation. Those patients with RV failure and RVADs experience significantly increased postoperative mortality compared to those without RV dysfunction.

  15. Predictions and Experimental Microstructural Characterization of High Strain Rate Failure Modes in Layered Aluminum Composites

    NASA Astrophysics Data System (ADS)

    Khanikar, Prasenjit

    Different aluminum alloys can be combined, as composites, for tailored dynamic applications. Most investigations pertaining to metallic alloy layered composites, however, have been based on quasi-static approaches. The dynamic failure of layered metallic composites, therefore, needs to be characterized in terms of strength, toughness, and fracture response. A dislocation-density based crystalline plasticity formulation, finite-element techniques, rational crystallographic orientation relations and a new fracture methodology were used to predict the failure modes associated with the high strain rate behavior of aluminum layered composites. Two alloy layers, a high strength alloy, aluminum 2195, and an aluminum alloy 2139, with high toughness, were modeled with representative microstructures that included precipitates, dispersed particles, and different grain boundary (GB) distributions. The new fracture methodology, based on an overlap method and phantom nodes, is used with a fracture criteria specialized for fracture on different cleavage planes. One of the objectives of this investigation, therefore, was to determine the optimal arrangements of the 2139 and 2195 aluminum alloys for a metallic layered composite that would combine strength, toughness and fracture resistance for high strain-rate applications. Different layer arrangements were investigated for high strain-rate applications, and the optimal arrangement was with the high toughness 2139 layer on the bottom, which provided extensive shear strain localization, and the high strength 2195 layer on the top for high strength resistance. The layer thickness of the bottom high toughness layer also affected the bending behavior of the roll-boned interface and the potential delamination of the layers. Shear strain localization, dynamic cracking and delamination were the mutually competing failure mechanisms for the layered metallic composite, and control of these failure modes can be optimized for high strain

  16. Central Venous Pressure After Coronary Artery Bypass Surgery: Does it Predict Postoperative Mortality or Renal Failure?

    PubMed Central

    Williams, Judson B.; Peterson, Eric D.; Wojdyla, Daniel; Ferguson, T. Bruce; Smith, Peter K.; Milano, Carmelo A.; Lopes, Renato D.

    2015-01-01

    Background While hemodynamic monitoring is often performed following coronary artery bypass grafting (CABG), the relationship between postoperative central venous pressure (CVP) measurement and clinical outcomes is unknown. Methods Detailed clinical data were analyzed from 2,390 randomly selected patients undergoing high risk CABG or CABG/valve at 55 hospitals participating in the Society of Thoracic Surgeons' National Cardiac Surgery Database from 2004 to 2005. Eligible patients underwent elective/urgent isolated CABG with an ejection fraction < 40%, or elective/urgent CABG at age ≥65 years with diabetes or a glomerular filtration rate 60 mL/min per 1.73 m2. Correlation between post-operative CVP and in-hospital / 30-day mortality and renal failure was assessed as a continuous variable, both unadjusted and after adjusting for important clinical factors using logistic regression modeling. Results Mean age was 72 years, 54% of patients had diabetes mellitus, 49% were urgent procedures, and mean cardiopulmonary bypass time was 105 minutes. Patients’ CVP 6 hours post-operation was strongly associated with in-hospital and 30 day mortality: odds ratio (OR) 1.5 (95% confidence interval [CI] 1.23, 1.87) for every 5 mmHg increase in CVP, p<0.0001. This association remained significant after risk-adjustment for cardiac index: adjusted OR 1.44 (95% CI 1.10, 1.89), p<0.01. A model adjusting for cardiac index also revealed increased incidence of mortality or renal failure: adjusted OR 1.5 (95% CI 1.28, 1.86) for every 5 mmHg increase in CVP, p<0.0001. Conclusion Patients’ central venous pressure at 6 hours following CABG surgery was highly predictive of operative mortality or renal failure, independent of cardiac index and other important clinical variables. Future studies will need to assess whether post-operative CVP can be used to guide intervention and improve outcomes. PMID:25035048

  17. A clinical score to predict acute renal failure after cardiac surgery.

    PubMed

    Thakar, Charuhas V; Arrigain, Susana; Worley, Sarah; Yared, Jean-Pierre; Paganini, Emil P

    2005-01-01

    The risk of mortality associated with acute renal failure (ARF) after open-heart surgery continues to be distressingly high. Accurate prediction of ARF provides an opportunity to develop strategies for early diagnosis and treatment. The aim of this study was to develop a clinical score to predict postoperative ARF by incorporating the effect of all of its major risk factors. A total of 33,217 patients underwent open-heart surgery at the Cleveland Clinic Foundation (1993 to 2002). The primary outcome was ARF that required dialysis. The scoring model was developed in a randomly selected test set (n = 15,838) and was validated on the remaining patients. Its predictive accuracy was compared by area under the receiver operating characteristic curve. The score ranges between 0 and 17 points. The ARF frequency at each score level in the validation set fell within the 95% confidence intervals (CI) of the corresponding frequency in the test set. Four risk categories of increasing severity (scores 0 to 2, 3 to 5, 6 to 8, and 9 to 13) were formed arbitrarily. The frequency of ARF across these categories in the test set ranged between 0.5 and 22.1%. The score was also valid in predicting ARF across all risk categories. The area under the receiver operating characteristic curve for the score in the test set was 0.81 (95% CI 0.78 to 0.83) and was similar to that in the validation set (0.82; 95% CI 0.80 to 0.85; P = 0.39). In conclusion, a score is valid and accurate in predicting ARF after open-heart surgery; along with increasing its clinical utility, the score can help in planning future clinical trials of ARF.

  18. The EST Model for Predicting Progressive Damage and Failure of Open Hole Bending Specimens

    NASA Technical Reports Server (NTRS)

    Joseph, Ashith P. K.; Waas, Anthony M.; Pineda, Evan J.

    2016-01-01

    Progressive damage and failure in open hole composite laminate coupons subjected to flexural loading is modeled using Enhanced Schapery Theory (EST). Previous studies have demonstrated that EST can accurately predict the strength of open hole coupons under remote tensile and compressive loading states. This homogenized modeling approach uses single composite shell elements to represent the entire laminate in the thickness direction and significantly reduces computational cost. Therefore, when delaminations are not of concern or are active in the post-peak regime, the version of EST presented here is a good engineering tool for predicting deformation response. Standard coupon level tests provides all the input data needed for the model and they are interpreted in conjunction with finite element (FE) based simulations. Open hole bending test results of three different IM7/8552 carbon fiber composite layups agree well with EST predictions. The model is able to accurately capture the curvature change and deformation localization in the specimen at and during the post catastrophic load drop event.

  19. A state-based approach to trend recognition and failure prediction for the Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Nelson, Kyle S.; Hadden, George D.

    1992-01-01

    A state-based reasoning approach to trend recognition and failure prediction for the Altitude Determination, and Control System (ADCS) of the Space Station Freedom (SSF) is described. The problem domain is characterized by features (e.g., trends and impending failures) that develop over a variety of time spans, anywhere from several minutes to several years. Our state-based reasoning approach, coupled with intelligent data screening, allows features to be tracked as they develop in a time-dependent manner. That is, each state machine has the ability to encode a time frame for the feature it detects. As features are detected, they are recorded and can be used as input to other state machines, creating a hierarchical feature recognition scheme. Furthermore, each machine can operate independently of the others, allowing simultaneous tracking of features. State-based reasoning was implemented in the trend recognition and the prognostic modules of a prototype Space Station Freedom Maintenance and Diagnostic System (SSFMDS) developed at Honeywell's Systems and Research Center.

  20. Failure Predictions for VHTR Core Components using a Probabilistic Contiuum Damage Mechanics Model

    SciTech Connect

    Fok, Alex

    2013-10-30

    The proposed work addresses the key research need for the development of constitutive models and overall failure models for graphite and high temperature structural materials, with the long-term goal being to maximize the design life of the Next Generation Nuclear Plant (NGNP). To this end, the capability of a Continuum Damage Mechanics (CDM) model, which has been used successfully for modeling fracture of virgin graphite, will be extended as a predictive and design tool for the core components of the very high- temperature reactor (VHTR). Specifically, irradiation and environmental effects pertinent to the VHTR will be incorporated into the model to allow fracture of graphite and ceramic components under in-reactor conditions to be modeled explicitly using the finite element method. The model uses a combined stress-based and fracture mechanics-based failure criterion, so it can simulate both the initiation and propagation of cracks. Modern imaging techniques, such as x-ray computed tomography and digital image correlation, will be used during material testing to help define the baseline material damage parameters. Monte Carlo analysis will be performed to address inherent variations in material properties, the aim being to reduce the arbitrariness and uncertainties associated with the current statistical approach. The results can potentially contribute to the current development of American Society of Mechanical Engineers (ASME) codes for the design and construction of VHTR core components.

  1. A co-training-based approach for prediction of remaining useful life utilizing both failure and suspension data

    NASA Astrophysics Data System (ADS)

    Hu, Chao; Youn, Byeng D.; Kim, Taejin; Wang, Pingfeng

    2015-10-01

    Traditional data-driven prognostics often requires some amount of failure data for the offline training in order to achieve good accuracy for the online prediction. Failure data refer to condition monitoring data collected from the very beginning of an engineered system's lifetime till the occurrence of its failure. However, in many engineered systems, failure data are fairly expensive and time-consuming to obtain while suspension data are readily available. Suspension data refer to condition monitoring data acquired from the very beginning of an engineered system's lifetime till planned inspection or maintenance when the system is taken out of service. In such cases, it becomes essentially critical to utilize suspension data which may carry rich information regarding the degradation trend and help achieve more accurate remaining useful life (RUL) prediction. To this end, this paper proposes a co-training-based data-driven prognostic approach, denoted by COPROG, which uses two data-driven algorithms with each predicting RULs of suspension units for the other. After a suspension unit is chosen and its RUL is predicted by an individual algorithm, it becomes a virtual failure unit that is added to the training data set of the other individual algorithm. Results obtained from two case studies suggest that COPROG gives more accurate RUL prediction, as compared to any individual algorithm with no use of suspension data, and that COPROG can effectively exploit suspension data to improve the prognostic accuracy.

  2. Failure behavior of internally pressurized flawed and unflawed steam generator tubing at high temperatures -- Experiments and comparison with model predictions

    SciTech Connect

    Majumdar, S.; Shack, W.J.; Diercks, D.R.; Mruk, K.; Franklin, J.; Knoblich, L.

    1998-03-01

    This report summarizes experimental work performed at Argonne National Laboratory on the failure of internally pressurized steam generator tubing at high temperatures ({le} 700 C). A model was developed for predicting failure of flawed and unflawed steam generator tubes under internal pressure and temperature histories postulated to occur during severe accidents. The model was validated by failure tests on specimens with part-through-wall axial and circumferential flaws of various lengths and depths, conducted under various constant and ramped internal pressure and temperature conditions. The failure temperatures predicted by the model for two temperature and pressure histories, calculated for severe accidents initiated by a station blackout, agree very well with tests performed on both flawed and unflawed specimens.

  3. Failure Mechanisms and Life Prediction of Thermal and Environmental Barrier Coatings under Thermal Gradients

    NASA Technical Reports Server (NTRS)

    Zju, Dongming; Ghosn, Louis J.; Miller, Robert A.

    2008-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) will play an increasingly important role in gas turbine engines because of their ability to further raise engine temperatures. However, the issue of coating durability is of major concern under high-heat-flux conditions. In particular, the accelerated coating delamination crack growth under the engine high heat-flux conditions is not well understood. In this paper, a laser heat flux technique is used to investigate the coating delamination crack propagation under realistic temperature-stress gradients and thermal cyclic conditions. The coating delamination mechanisms are investigated under various thermal loading conditions, and are correlated with coating dynamic fatigue, sintering and interfacial adhesion test results. A coating life prediction framework may be realized by examining the crack initiation and propagation driving forces for coating failure under high-heat-flux test conditions.

  4. Prediction of reliability on thermoelectric module through accelerated life test and Physics-of-failure

    NASA Astrophysics Data System (ADS)

    Choi, Hyoung-Seuk; Seo, Won-Seon; Choi, Duck-Kyun

    2011-09-01

    Thermoelectric cooling module (TEM) which is electric device has a mechanical stress because of temperature gradient in itself. It means that structure of TEM is vulnerable in an aspect of reliability but research on reliability of TEM was not performed a lot. Recently, the more the utilization of thermoelectric cooling devices grows, the more the needs for life prediction and improvement are increasing. In this paper, we investigated life distribution, shape parameter of the TEM through accelerated life test (ALT). And we discussed about how to enhance life of TEM through the Physics-of-failure. Experimental results of ALT showed that the thermoelectric cooling module follows the Weibull distribution, shape parameter of which is 3.6. The acceleration model is coffin Coffin-Manson and material constant is 1.8.

  5. Predicting treatment failure in severe sepsis and septic shock: looking for the Holy Grail

    PubMed Central

    2013-01-01

    Procalcitonin has been proposed as a specific biomarker of bacterial infections and has been related to the severity of sepsis. The prognostic ability of the initial concentrations of procalcitonin in sepsis is controversial. Some studies find higher initial concentrations in non-survivors but others find no differences. Prognostic assessment based on follow-up of procalcitonin levels may be better than evaluation of the initial levels of procalcitonin. The persistence of elevated procalcitonin levels is indicative of poor prognosis and is associated with mortality. Procalcitonin kinetics could be a tool for assessing the evolution of severe sepsis and sepsis shock. Procalcitonin should find its place as a biomarker for predicting treatment failure of severe sepsis and septic shock. PMID:24004571

  6. A Novel Method for the Prediction of Critical Inclusion Size Leading to Fatigue Failure

    NASA Astrophysics Data System (ADS)

    Saberifar, S.; Mashreghi, A. R.

    2012-06-01

    The fatigue behavior of two commercial 30MnVS6 steels with similar microstructure and mechanical properties containing inclusions of different sizes were studied in the 107 cycles fatigue regime. The scanning electron microscopy (SEM) investigations of the fracture surfaces revealed that the nonmetallic inclusions are the main sources of fatigue crack initiation. Calculated according to the Murakami's model, the stress intensity factors were found to be suitable for the assessment of fatigue behavior. In this article, a new method is proposed for the prediction of the critical inclusion size, using Murakami's model. According to this method, a critical stress intensity factor was determined for the estimation of the critical inclusion size causing the fatigue failure.

  7. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis

    PubMed Central

    Tangri, Navdeep; Grams, Morgan E.; Levey, Andrew S.; Coresh, Josef; Appel, Lawrence; Astor, Brad C.; Chodick, Gabriel; Collins, Allan J.; Djurdjev, Ognjenka; Elley, C. Raina; Evans, Marie; Garg, Amit X.; Hallan, Stein I.; Inker, Lesley; Ito, Sadayoshi; Jee, Sun Ha; Kovesdy, Csaba P.; Kronenberg, Florian; Lambers Heerspink, Hiddo J.; Marks, Angharad; Nadkarni, Girish N.; Navaneethan, Sankar D.; Nelson, Robert G.; Titze, Stephanie; Sarnak, Mark J.; Stengel, Benedicte; Woodward, Mark; Iseki, Kunitoshi

    2016-01-01

    Importance Identifying patients at risk of chronic kidney disease (CKD) progression may facilitate more optimal nephrology care. Kidney failure risk equations (KFREs) were previously developed and validated in two Canadian cohorts. Validation in other regions and in CKD populations not under the care of a nephrologist is needed. Objective To evaluate the accuracy of the KFREs across different geographic regions and patient populations through individual-participant data meta-analysis. Data Sources Thirty-one cohorts, including 721,357 participants with CKD Stages 3–5 in over 30 countries spanning 4 continents, were studied. These cohorts collected data from 1982 through 2014. Study Selection Cohorts participating in the CKD Prognosis Consortium with data on end-stage renal disease. Data Extraction and Synthesis Data were obtained and statistical analyses were performed between July 2012 and June 2015. Using the risk factors from the original KFREs, cohort-specific hazard ratios were estimated, and combined in meta-analysis to form new “pooled” KFREs. Original and pooled equation performance was compared, and the need for regional calibration factors was assessed. Main Outcome and Measure Kidney failure (treatment by dialysis or kidney transplantation). Results During a median follow-up of 4 years, 23,829 cases of kidney failure were observed. The original KFREs achieved excellent discrimination (ability to differentiate those who developed kidney failure from those who did not) across all cohorts (overall C statistic, 0.90 (95% CI 0.89–0.92) at 2 years and 0.88 (95% CI 0.86–0.90) at 5 years); discrimination in subgroups by age, race, and diabetes status was similar. There was no improvement with the pooled equations. Calibration (the difference between observed and predicted risk) was adequate in North American cohorts, but the original KFREs overestimated risk in some non-North American cohorts. Addition of a calibration factor that lowered the baseline

  8. Strength Evaluation and Failure Prediction of Short Carbon Fiber Reinforced Nylon Spur Gears by Finite Element Modeling

    NASA Astrophysics Data System (ADS)

    Hu, Zhong; Hossan, Mohammad Robiul

    2013-06-01

    In this paper, short carbon fiber reinforced nylon spur gear pairs, and steel and unreinforced nylon spur gear pairs have been selected for study and comparison. A 3D finite element model was developed to simulate the multi-axial stress-strain behaviors of the gear tooth. Failure prediction has been conducted based on the different failure criteria, including Tsai-Wu criterion. The tooth roots, where has stress concentration and the potential for failure, have been carefully investigated. The modeling results show that the short carbon fiber reinforced nylon gear fabricated by properly controlled injection molding processes can provide higher strength and better performance.

  9. To what extent can linear finite element models of human femora predict failure under stance and fall loading configurations?

    PubMed

    Schileo, Enrico; Balistreri, Luca; Grassi, Lorenzo; Cristofolini, Luca; Taddei, Fulvia

    2014-11-07

    Proximal femur strength estimates from computed tomography (CT)-based finite element (FE) models are finding clinical application. Published models reached a high in-vitro accuracy, yet many of them rely on nonlinear methodologies or internal best-fitting of parameters. The aim of the present study is to verify to what extent a linear FE modelling procedure, fully based on independently determined parameters, can predict the failure characteristics of the proximal femur in stance and sideways fall loading configurations. Fourteen fresh-frozen cadaver femora were CT-scanned. Seven femora were tested to failure in stance loading conditions, and seven in fall. Fracture was monitored with high-speed videos. Linear FE models were built from CT images according to a procedure already validated in the prediction of strains. An asymmetric maximum principal strain criterion (0.73% tensile, 1.04% compressive limit) was used to define a node-based risk factor (RF). FE-predicted failure load, mode (tensile/compressive) and location were determined from the first node reaching RF=1. FE-predicted and measured failure loads were highly correlated (R(2)=0.89, SEE=814N). In all specimens, FE models correctly identified the failure mode (tensile in stance, compressive in fall) and the femoral region where fracture started (supero-lateral neck aspect). The location of failure onset was accurately predicted in eight specimens. In summary, a simple FE model, adaptable in the future to multiple loads (e.g. including muscles), was highly correlated with experimental failure in two loading conditions on specimens ranging from normal to osteoporotic. Thus, it can be suitable for use in clinical studies.

  10. Diastolic Heart Failure Predicted by Left Atrial Expansion Index in Patients with Severe Diastolic Dysfunction

    PubMed Central

    Hsiao, Shih-Hung; Chiou, Kuan-Rau

    2016-01-01

    Background Left atrial (LA) echocardiographic parameters are increasingly used to predict clinically relevant cardiovascular events. The study aims to evaluate the LA expansion index (LAEI) for predicting diastolic heart failure (HF) in patients with severe left ventricular (LV) diastolic dysfunction. Methods This prospective study enrolled 162 patients (65% male) with preserved LV systolic function and severe diastolic dysfunction (132 grade 2 patients, 30 grade 3 patients). All patients had sinus rhythm at enrollment. The LAEI was calculated as (Volmax - Volmin) x 100% / Volmin, where Volmax was defined as maximal LA volume and Volmin was defined as minimal volume. The endpoint was hospitalization for HF withp reserved LV ejection fraction (HFpEF). Results The median follow-up duration was 2.9 years. Fifty-four patients had cardiovascular events, including 41 diastolic and 8 systolic HF hospitalizations. In these 54 patients, 13 in-hospital deaths and 5 sudden out-of-hospital deaths occurred. Multivariate analyses revealed that HFpEF was associated with LAEI.and atrial fibrillation during follow-up. For predicting HFpEF, the LAEI had a hazard ratio of 1.197per 10% decrease. In patients who had HFpEF events, the LAEI significantly (P< 0.0001) decreased from 69±18% to 39±11% during hospitalization. Although the LAEI improved during follow-up (53±13%), it did not return to baseline. Conclusions The LAEI predicts HFpEF in patients with severe diastolic dysfunction; it worsens during HFpEF events and partially recovers during followup. PMID:27622475

  11. Transvaginal ultrasonographic cervical measurement in predicting failed labor induction and cesarean delivery for failure to progress in nulliparous women.

    PubMed

    Park, Kyo Hoon

    2007-08-01

    The aim of this study was to evaluate the value of transvaginal sonographic cervical measurement in predicting failed labor induction and cesarean delivery for failure to progress in nulliparous women. One hundred and sixty-one women scheduled for labor induction underwent transvaginal ultrasonography and digital cervical examinations. Logistic regression demonstrated that cervical length and gestational age at induction, but not the Bishop score, significantly and independently predicted failed labor induction. According to the receiver operating characteristic curves analysis, the best cut-off value of cervical length for predicting failed labor induction was 28 mm, with a sensitivity of 62% and a specificity of 60%. In terms of the likelihood of a cesarean delivery for failure to progress as the outcome variable, logistic regression indicated that maternal height and birth weight, but not cervical length or Bishop score, were significantly and independently associated with an increased risk of cesarean delivery for failure to progress. Transvaginal sonographic measurements of cervical length thus independently predicted failed labor induction in nulliparous women. However, the relatively poor predictive performance of this test undermines its clinical usefulness as a predictor of failed labor induction. Moreover, cervical length appears to have a poor predictive value for the likelihood of a cesarean delivery for failure to progress.

  12. The failure analysis and lifetime prediction for the solder joint of the magnetic head

    NASA Astrophysics Data System (ADS)

    Xiao, Xianghui; Peng, Minfang; Cardoso, Jaime S.; Tang, Rongjun; Zhou, YingLiang

    2015-02-01

    Micro-solder joint (MSJ) lifetime prediction methodology and failure analysis (FA) are to assess reliability by fatigue model with a series of theoretical calculations, numerical simulation and experimental method. Due to shortened time of solder joints on high-temperature, high-frequency sampling error that is not allowed in productions may exist in various models, including round-off error. Combining intermetallic compound (IMC) growth theory and the FA technology for the magnetic head in actual production, this thesis puts forward a new growth model to predict life expectancy for solder joint of the magnetic head. And the impact of IMC, generating from interface reaction between slider (magnetic head, usually be called slider) and bonding pad, on mechanical performance during aging process is analyzed in it. By further researching on FA of solder ball bonding, thesis chooses AuSn4 growth model that affects least to solder joint mechanical property to indicate that the IMC methodology is suitable to forecast the solder lifetime. And the diffusion constant under work condition 60 °C is 0.015354; the solder lifetime t is 14.46 years.

  13. Biomarkers to Predict Reverse Remodeling and Myocardial Recovery in Heart Failure.

    PubMed

    Motiwala, Shweta R; Gaggin, Hanna K

    2016-10-01

    Left ventricular remodeling appears to be a critical link between cardiac injury and the development and progression of heart failure with reduced ejection fraction (HFrEF). Several drug and device therapies that modify and reverse the remodeling process in patients with HFrEF are closely associated with improvement in clinical outcomes. Reverse remodeling, including partial or complete recovery of systolic function and structure, is possible but its determinants are incompletely understood. Methods to predict reverse remodeling in response to therapy are not well defined. Though non-invasive imaging techniques remain the most widely used methods of assessing reverse remodeling, serum biomarkers are now being investigated as more specific, mechanistically driven, and clinically useful predictors of reverse remodeling. Biomarkers that reflect myocyte stretch and stress, myocyte injury and necrosis, inflammation and fibrosis, and extracellular matrix turnover may be particularly valuable for predicting pathophysiologic changes and prognosis in individual patients. Their use may ultimately allow improved application of precision medicine in chronic HF.

  14. The failure analysis and lifetime prediction for the solder joint of the magnetic head

    NASA Astrophysics Data System (ADS)

    Xiao, Xianghui; Peng, Minfang; Cardoso, Jaime S.; Tang, Rongjun; Zhou, YingLiang

    2014-09-01

    Micro-solder joint (MSJ) lifetime prediction methodology and failure analysis (FA) are to assess reliability by fatigue model with a series of theoretical calculations, numerical simulation and experimental method. Due to shortened time of solder joints on high-temperature, high-frequency sampling error that is not allowed in productions may exist in various models, including round-off error. Combining intermetallic compound (IMC) growth theory and the FA technology for the magnetic head in actual production, this thesis puts forward a new growth model to predict life expectancy for solder joint of the magnetic head. And the impact of IMC, generating from interface reaction between slider (magnetic head, usually be called slider) and bonding pad, on mechanical performance during aging process is analyzed in it. By further researching on FA of solder ball bonding, thesis chooses AuSn4 growth model that affects least to solder joint mechanical property to indicate that the IMC methodology is suitable to forecast the solder lifetime. And the diffusion constant under work condition 60 °C is 0.015354; the solder lifetime t is 14.46 years.

  15. Life Prediction and Classification of Failure Modes in Solid State Luminaires Using Bayesian Probabilistic Models

    SciTech Connect

    Lall, Pradeep; Wei, Junchao; Sakalaukus, Peter

    2014-05-27

    A new method has been developed for assessment of the onset of degradation in solid state luminaires to classify failure mechanisms by using metrics beyond lumen degradation that are currently used for identification of failure. Luminous Flux output, Correlated Color Temperature Data on Philips LED Lamps has been gathered under 85°C/85%RH till lamp failure. The acquired data has been used in conjunction with Bayesian Probabilistic Models to identify luminaires with onset of degradation much prior to failure through identification of decision boundaries between lamps with accrued damage and lamps beyond the failure threshold in the feature space. In addition luminaires with different failure modes have been classified separately from healthy pristine luminaires. It is expected that, the new test technique will allow the development of failure distributions without testing till L70 life for the manifestation of failure.

  16. Serum microRNA expression patterns that predict early treatment failure in prostate cancer patients

    PubMed Central

    Singh, Prashant K.; Preus, Leah; Hu, Qiang; Yan, Li; Long, Mark D.; Morrison, Carl D.; Nesline, Mary; Johnson, Candace S.; Koochekpour, Shahriar; Kohli, Manish; Liu, Song; Trump, Donald L.

    2014-01-01

    We aimed to identify microRNA (miRNA) expression patterns in the serum of prostate cancer (CaP) patients that predict the risk of early treatment failure following radical prostatectomy (RP). Microarray and Q-RT-PCR analyses identified 43 miRNAs as differentiating disease stages within 14 prostate cell lines and reflectedpublically available patient data. 34 of these miRNA were detectable in the serum of CaP patients. Association with time to biochemical progression was examined in a cohort of CaP patients following RP. A greater than two-fold increase in hazard of biochemical progression associated with altered expression of miR-103, miR-125b and miR-222 (p <.0008) in the serum of CaP patients. Prediction models based on penalized regression analyses showed that the levels of the miRNAs and PSA together were better at detecting false positives than models without miRNAs, for similar level of sensitivity. Analyses of publically available data revealed significant and reciprocal relationships between changes in CpG methylation and miRNA expression patterns suggesting a role for CpG methylation to regulate miRNA. Exploratory validation supported roles for miR-222 and miR-125b to predict progression risk in CaP. The current study established that expression patterns of serum-detectable miRNAs taken at the time of RP are prognostic for men who are at risk of experiencing subsequent early biochemical progression. These non-invasive approaches could be used to augment treatment decisions. PMID:24583788

  17. A Comprehensive Method for Predicting Fatal Liver Failure of Patients With Liver Cancer Resection

    PubMed Central

    Li, Jiangfa; Lei, Biao; Nie, Xingju; Lin, Linku; Tahir, Syed Abdul; Shi, Wuxiang; Jin, Junfei; He, Songqing

    2015-01-01

    Abstract There are many methods to assess liver function, but none of them has been verified as fully effective. The purpose of this study is to establish a comprehensive method evaluating perioperative liver reserve function (LRF) in patients with primary liver cancer (PLC). In this study, 310 PLC patients who underwent liver resection were included. The cohort was divided into a training set (n = 235) and a validation set (n = 75). The factors affecting postoperative liver dysfunction (POLD) during preoperative, intraoperative, and postoperative periods were confirmed by logistic regression analysis. The equation for calculating the preoperative liver functional evaluation index (PLFEI) was established; the cutoff value of PLFEI determined through analysis by receiver-operating characteristic curve was used to predict postoperative liver function. The data showed that body mass index, international normalized ratio, indocyanine green (ICG) retention rate at 15 minutes (ICGR15), ICG elimination rate, standard remnant liver volume (SRLV), operative bleeding volume (OBV), blood transfusion volume, and operative time were statistically different (all P < 0.05) between 2 groups of patients with and without POLD. The relationship among PLFEI, ICGR15, OBV, and SRLV is expressed as an equation of “PLFEI = 0.181 × ICGR15 + 0.001 × OBV − 0.008 × SRLV.” The cutoff value of PLFEI to predict POLD was −2.16 whose sensitivity and specificity were 90.3% and 73.5%, respectively. However, when predicting fatal liver failure (FLF), the cutoff value of PLFEI was switched to −1.97 whose sensitivity and specificity were 100% and 68.8%, respectively. PLFEI will be a more comprehensive, sensitive, and accurate index assessing perioperative LRF in liver cancer patients who receive liver resection. And keeping PLFEI <−1.97 is a safety margin for preventing FLF in PLC patients who underwent liver resection. PMID:25929924

  18. A comprehensive method for predicting fatal liver failure of patients with liver cancer resection.

    PubMed

    Li, Jiangfa; Lei, Biao; Nie, Xingju; Lin, Linku; Tahir, Syed Abdul; Shi, Wuxiang; Jin, Junfei; He, Songqing

    2015-05-01

    There are many methods to assess liver function, but none of them has been verified as fully effective. The purpose of this study is to establish a comprehensive method evaluating perioperative liver reserve function (LRF) in patients with primary liver cancer (PLC).In this study, 310 PLC patients who underwent liver resection were included. The cohort was divided into a training set (n = 235) and a validation set (n = 75). The factors affecting postoperative liver dysfunction (POLD) during preoperative, intraoperative, and postoperative periods were confirmed by logistic regression analysis. The equation for calculating the preoperative liver functional evaluation index (PLFEI) was established; the cutoff value of PLFEI determined through analysis by receiver-operating characteristic curve was used to predict postoperative liver function.The data showed that body mass index, international normalized ratio, indocyanine green (ICG) retention rate at 15 minutes (ICGR15), ICG elimination rate, standard remnant liver volume (SRLV), operative bleeding volume (OBV), blood transfusion volume, and operative time were statistically different (all P < 0.05) between 2 groups of patients with and without POLD. The relationship among PLFEI, ICGR15, OBV, and SRLV is expressed as an equation of "PLFEI = 0.181 × ICGR15 + 0.001 × OBV - 0.008 × SRLV." The cutoff value of PLFEI to predict POLD was -2.16 whose sensitivity and specificity were 90.3% and 73.5%, respectively. However, when predicting fatal liver failure (FLF), the cutoff value of PLFEI was switched to -1.97 whose sensitivity and specificity were 100% and 68.8%, respectively.PLFEI will be a more comprehensive, sensitive, and accurate index assessing perioperative LRF in liver cancer patients who receive liver resection. And keeping PLFEI <-1.97 is a safety margin for preventing FLF in PLC patients who underwent liver resection.

  19. Systemic Inflammatory Response and Serum Lipopolysaccharide Levels Predict Multiple Organ Failure and Death in Alcoholic Hepatitis

    PubMed Central

    Michelena, Javier; Altamirano, José; Abraldes, Juan G.; Affò, Silvia; Morales-Ibanez, Oriol; Sancho-Bru, Pau; Dominguez, Marlene; García-Pagán, Juan Carlos; Fernández, Javier; Arroyo, Vicente; Ginès, Pere; Louvet, Alexandre; Mathurin, Philippe; Mehal, Wajahat Z.; Caballería, Juan; Bataller, Ramón

    2015-01-01

    Alcoholic hepatitis (AH) frequently progresses to multiple organ failure (MOF) and death. However, the driving factors are largely unknown. At admission, patients with AH often show criteria of systemic inflammatory response syndrome (SIRS) even in the absence of an infection. We hypothesize that the presence of SIRS may predispose to MOF and death. To test this hypothesis, we studied a cohort including 162 patients with biopsy-proven AH. The presence of SIRS and infections was assessed in all patients, and multivariate analyses identified variables independently associated with MOF and 90-day mortality. At admission, 32 (19.8%) patients were diagnosed with a bacterial infection, while 75 (46.3%) fulfilled SIRS criteria; 58 patients (35.8%) developed MOF during hospitalization. Short-term mortality was significantly higher among patients who developed MOF (62.1% versus 3.8%, P <0.001). The presence of SIRS was a major predictor of MOF (odds ratio = 2.69, P=0.025) and strongly correlated with mortality. Importantly, the course of patients with SIRS with and without infection was similar in terms of MOF development and short-term mortality. Finally, we sought to identify serum markers that differentiate SIRS with and without infection. We studied serum levels of high-sensitivity C-reactive protein, procalcitonin, and lipopolysaccharide at admission. All of them predicted mortality. Procalcitonin, but not high-sensitivity C-reactive protein, serum levels identified those patients with SIRS and infection. Lipopolysaccharide serum levels predicted MOF and the response to prednisolone. Conclusion In the presence or absence of infections, SIRS is a major determinant of MOF and mortality in AH, and the mechanisms involved in the development of SIRS should be investigated; procalcitonin serum levels can help to identify patients with infection, and lipopolysaccharide levels may help to predict mortality and the response to steroids. PMID:25761863

  20. Prediction factors for failure to seek treatment following traumatic dental injuries to primary teeth.

    PubMed

    Firmino, Ramon Targino; Siqueira, Maria Betânia Lins Dantas; Vieira-Andrade, Raquel Gonçalves; Gomes, Genara Brum; Martins, Carolina Castro; Paiva, Saul Martins; Granville-Garcia, Ana Flávia

    2014-01-01

    The objective of this study was to evaluate prediction factors for failure to seek treatment following a traumatic dental injury (TDI) to primary teeth among preschool children in the city of Campina Grande, Brazil. A cross-sectional study was carried out involving 277 children 3 to 5 years of age, with TDI, enrolled in public and private preschools. Parents filled out a form addressing demographic data and whether or not they had sought treatment. Clinical examinations were performed by three dentists who had undergone a calibration exercise (Kappa: 0.85 to 0.90) for the evaluation of TDI. Bivariate and multivariate Poisson regression models were constructed (α=5%). Enamel fracture was the most prevalent type of TDI (48.7%) and the upper central incisors were the most affected teeth (88.4%). The frequency of seeking dental treatment was low (9.7%). The following variables were associated with failure to seek treatment following TDI: a household income greater than one minimum wage (PR=1.170; 95%CI 1.018-1.341), parents/caregivers' perception of a child's oral health as poor (PR=1.100; 95%CI 1.026-1.176), and the non-perception of TDI by parents/caregivers (PR=1.250; 95%CI 1.142-1.360). In the present study, the frequency of seeking treatment following TDI was low, and parents/caregivers with a higher income, a poor perception of their child's oral health and a lack of awareness regarding the trauma were more likely to fail to seek treatment following TDI to primary teeth.

  1. Urinary cadmium levels predict mortality of patients with acute heart failure

    PubMed Central

    Hsu, Ching-Wei; Weng, Cheng-Hao; Lee, Cheng-Chia; Lin-Tan, Dan-Tzu; Chu, Pao-Hsien; Chen, Kuan-Hsing; Yen, Tzung-Hai; Huang, Wen-Hung

    2017-01-01

    Background Acute heart failure (AHF) is a serious condition that is associated with increased mortality in critically ill patients. Previous studies indicated that environmental exposure to cadmium increases mortality of general populations. However, the relationship of cadmium exposure and mortality is unclear for AHF patients. Materials and methods A total of 153 patients with AHF in intensive care units (ICUs) met the inclusion criteria and were followed up for 6 months. Demographic data, AHF etiology, hematological and biochemical data, and hospital mortality were recorded. The scores of two predictive systems (Sequential Organ Failure Assessment [SOFA], Acute Physiology and Chronic Health Evaluation II [APACHE II]) for mortality in critically ill patients were calculated, and urinary cadmium levels were recorded. Results At the end of the follow-up period, the mortality rate was 24.8%. The survivors (n=115) had higher urinary cadmium levels on day 1 (D1UCd) of ICU admission than non-survivors (n=38). A multiple linear regression analysis revealed a positive correlation between D1UCd and acute kidney injury, but a negative correlation between D1UCd and the level of serum albumin. A multivariate Cox analysis indicated that D1UCd was an independent predictor of mortality in AHF patients. For each increment of 1 μg of D1UCd, the hazard ratio for ICU mortality was 1.20 (95% confidence interval [CI]: 1.09–1.32, P<0.001). The area under the receiver operating characteristic curve for D1UCd was 0.84 (95% CI: 0.78–0.91), better than the values for the SOFA and APACHE II systems. Conclusion The D1UCd may serve as a single predictor of hospital mortality for AHF patients in the ICU. Because of the high mortality and smaller sample size, more investigations are required to confirm these observations and elucidate the underlying mechanisms. PMID:28392700

  2. Systolic Strain Abnormalities to Predict Hospital Readmission in Patients With Heart Failure and Normal Ejection Fraction

    PubMed Central

    Borer, Steven M.; Kokkirala, Aravind; O'Sullivan, David M.; Silverman, David I.

    2011-01-01

    Background Despite intensive investigation, the pathogenesis of heart failure with normal ejection fraction (HFNEF) remains unclear. We hypothesized that subtle abnormalities of systolic function might play a role, and that abnormal systolic strain and strain rate would provide a marker for adverse outcomes. Methods Patients of new CHF and left ventricular ejection fraction > 50% were included. Exclusion criteria were recent myocardial infarction, severe valvular heart disease, severe left ventricular hypertrophy (septum >1.8 cm), or a technically insufficient echocardiogram. Average peak systolic strain and strain rate were measured using an off-line grey scale imaging technique. Systolic strain and strain rate for readmitted patients were compared with those who remained readmission-free. Results One hundred consecutive patients with a 1st admission for HFNEF from January 1, 2004 through December 31, 2007, inclusive, were analyzed. Fifty two patients were readmitted with a primary diagnosis of heart failure. Systolic strain and strain rates were reduced in both study groups compared to controls. However, systolic strain did not differ significantly between the two groups (-11.7% for those readmitted compared with -12.9% for those free from readmission, P = 0.198) and systolic strain rates also were similar (-1.05 s-1 versus -1.09 s-1, P = 0.545). E/e’ was significantly higher in readmitted patients compared with those who remained free from readmission (14.5 versus 11.0, P = 0.013). E/e’ (OR 1.189, 95% CI 1.026-1.378; P = 0.021) was found to be an independent predictor for HFNEF readmission. Conclusions Among patients with new onset HFNEF, SS and SR rates are reduced compared with patients free of HFNEF, but do not predict hospital readmission. Elevated E/e’ is a predictor of readmission in these patients.

  3. A Statistical Approach to Predict the Failure Enthalpy and Reliability of Irradiated PWR Fuel Rods During Reactivity-Initiated Accidents

    SciTech Connect

    Nam, Cheol; Jeong, Yong-Hwan; Jung, Youn-Ho

    2001-11-15

    During the last decade, the failure behavior of high-burnup fuel rods under a reactivity-initiated accident (RIA) condition has been a serious concern since fuel rod failures at low enthalpy have been observed. This has resulted in the reassessment of existing licensing criteria and failure-mode study. To address the issue, a statistics-based methodology is suggested to predict failure probability of irradiated fuel rods under an RIA. Based on RIA simulation results in the literature, a failure enthalpy correlation for an irradiated fuel rod is constructed as a function of oxide thickness, fuel burnup, and pulse width. Using the failure enthalpy correlation, a new concept of ''equivalent enthalpy'' is introduced to reflect the effects of the three primary factors as well as peak fuel enthalpy into a single damage parameter. Moreover, the failure distribution function with equivalent enthalpy is derived, applying a two-parameter Weibull statistical model. Finally, the sensitivity analysis is carried out to estimate the effects of burnup, corrosion, peak fuel enthalpy, pulse width, and cladding materials used.

  4. Trend recognition and failure prediction of the attitude determination and control system of the Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Nelson, Kyle S.; Hadden, George D.

    An approach to automated trend recognition and failure prediction in the health parameter data of spacecraft is described. The approach, State-Based Feature Recognition (SBER), combines intelligent data filtering with state machines to detect the presence of features (trends and impending failures) in the health parameter data of spacecraft. SBFR, when implemented in a space-based or ground-based monitoring system, can increase spacecraft autonomy and decrease technician workload. An implemented, prototype Space Station Freedom (SSF) Maintenance and Diagnostic System (SSFMDS) that demonstrates the applicability of SBFR to trend detection and failure prediction will be described. SBFR allows features to be tracked, using specialized state machines, as they develop in a time-independent manner, allowing both short term and long term features to be detected. Each state machine operates independently of the other machines, making simultaneous feature tracking possible.

  5. Pitfalls and Precautions When Using Predicted Failure Data for Quantitative Analysis of Safety Risk for Human Rated Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Hatfield, Glen S.; Hark, Frank; Stott, James

    2016-01-01

    Launch vehicle reliability analysis is largely dependent upon using predicted failure rates from data sources such as MIL-HDBK-217F. Reliability prediction methodologies based on component data do not take into account risks attributable to manufacturing, assembly, and process controls. These sources often dominate component level reliability or risk of failure probability. While consequences of failure is often understood in assessing risk, using predicted values in a risk model to estimate the probability of occurrence will likely underestimate the risk. Managers and decision makers often use the probability of occurrence in determining whether to accept the risk or require a design modification. Due to the absence of system level test and operational data inherent in aerospace applications, the actual risk threshold for acceptance may not be appropriately characterized for decision making purposes. This paper will establish a method and approach to identify the pitfalls and precautions of accepting risk based solely upon predicted failure data. This approach will provide a set of guidelines that may be useful to arrive at a more realistic quantification of risk prior to acceptance by a program.

  6. DNA Methylation-Guided Prediction of Clinical Failure in High-Risk Prostate Cancer

    PubMed Central

    Joniau, Steven; Lerut, Evelyne; Laenen, Annouschka; Gevaert, Thomas; Gevaert, Olivier; Spahn, Martin; Kneitz, Burkhard; Gramme, Pierre; Helleputte, Thibault; Isebaert, Sofie; Haustermans, Karin; Bollen, Mathieu

    2015-01-01

    Background Prostate cancer (PCa) is a very heterogeneous disease with respect to clinical outcome. This study explored differential DNA methylation in a priori selected genes to diagnose PCa and predict clinical failure (CF) in high-risk patients. Methods A quantitative multiplex, methylation-specific PCR assay was developed to assess promoter methylation of the APC, CCND2, GSTP1, PTGS2 and RARB genes in formalin-fixed, paraffin-embedded tissue samples from 42 patients with benign prostatic hyperplasia and radical prostatectomy specimens of patients with high-risk PCa, encompassing training and validation cohorts of 147 and 71 patients, respectively. Log-rank tests, univariate and multivariate Cox models were used to investigate the prognostic value of the DNA methylation. Results Hypermethylation of APC, CCND2, GSTP1, PTGS2 and RARB was highly cancer-specific. However, only GSTP1 methylation was significantly associated with CF in both independent high-risk PCa cohorts. Importantly, trichotomization into low, moderate and high GSTP1 methylation level subgroups was highly predictive for CF. Patients with either a low or high GSTP1 methylation level, as compared to the moderate methylation groups, were at a higher risk for CF in both the training (Hazard ratio [HR], 3.65; 95% CI, 1.65 to 8.07) and validation sets (HR, 4.27; 95% CI, 1.03 to 17.72) as well as in the combined cohort (HR, 2.74; 95% CI, 1.42 to 5.27) in multivariate analysis. Conclusions Classification of primary high-risk tumors into three subtypes based on DNA methylation can be combined with clinico-pathological parameters for a more informative risk-stratification of these PCa patients. PMID:26086362

  7. Usefulness of Serum Triiodothyronine (T3) to Predict Outcomes in Patients Hospitalized With Acute Heart Failure.

    PubMed

    Rothberger, Gary D; Gadhvi, Sonya; Michelakis, Nickolaos; Kumar, Amit; Calixte, Rose; Shapiro, Lawrence E

    2017-02-15

    Thyroid hormone plays an important role in cardiac function. Low levels of serum triiodothyronine (T3) due to nonthyroidal illness syndrome may have adverse effects in heart failure (HF). This study was designed to assess the ability of T3 to predict in-hospital outcomes in patients with acute HF. In total, 137 patients without thyroid disease or treatment with drugs which affect TH levels, who were hospitalized with acute HF were prospectively enrolled and studied. TH levels were tested upon hospital admission, and outcomes were compared between patients with low (<2.3 pg/ml) and normal (≥2.3 pg/ml) free T3 levels as well as between those with low (<0.6 ng/ml) and normal (≥0.6 ng/ml) total T3 levels. Low free T3 correlated with an increased length of stay in the hospital (median 11 vs 7 days, p <0.001) and higher rates of intensive care unit admission (31.8% vs 16.9%, p = 0.047), with a trend toward increased need for invasive mechanical ventilation (9.0% vs 1.4%, p = 0.056). Low total T3 correlated with an increased length of stay in the hospital (median 11 vs 7 days, p <0.001) and increased need for invasive mechanical ventilation (9.8% vs 1.3%, p = 0.045). In conclusion, low T3 predicts worse hospital outcomes in patients with acute HF and can be useful in the risk stratification of these patients.

  8. GenSo-EWS: a novel neural-fuzzy based early warning system for predicting bank failures.

    PubMed

    Tung, W L; Quek, C; Cheng, P

    2004-05-01

    Bank failure prediction is an important issue for the regulators of the banking industries. The collapse and failure of a bank could trigger an adverse financial repercussion and generate negative impacts such as a massive bail out cost for the failing bank and loss of confidence from the investors and depositors. Very often, bank failures are due to financial distress. Hence, it is desirable to have an early warning system (EWS) that identifies potential bank failure or high-risk banks through the traits of financial distress. Various traditional statistical models have been employed to study bank failures [J Finance 1 (1975) 21; J Banking Finance 1 (1977) 249; J Banking Finance 10 (1986) 511; J Banking Finance 19 (1995) 1073]. However, these models do not have the capability to identify the characteristics of financial distress and thus function as black boxes. This paper proposes the use of a new neural fuzzy system [Foundations of neuro-fuzzy systems, 1997], namely the Generic Self-organising Fuzzy Neural Network (GenSoFNN) [IEEE Trans Neural Networks 13 (2002c) 1075] based on the compositional rule of inference (CRI) [Commun ACM 37 (1975) 77], as an alternative to predict banking failure. The CRI based GenSoFNN neural fuzzy network, henceforth denoted as GenSoFNN-CRI(S), functions as an EWS and is able to identify the inherent traits of financial distress based on financial covariates (features) derived from publicly available financial statements. The interaction between the selected features is captured in the form of highly intuitive IF-THEN fuzzy rules. Such easily comprehensible rules provide insights into the possible characteristics of financial distress and form the knowledge base for a highly desired EWS that aids bank regulation. The performance of the GenSoFNN-CRI(S) network is subsequently benchmarked against that of the Cox's proportional hazards model [J Banking Finance 10 (1986) 511; J Banking Finance 19 (1995) 1073], the multi

  9. Predicting time-to-failure in rock extrapolated from secondary creep

    NASA Astrophysics Data System (ADS)

    Hao, Sheng-Wang; Zhang, Bao-Ju; Tian, Ji-Feng; Elsworth, Derek

    2014-03-01

    Stress relaxation experiments are reported that culminate in energetic failure in rocks analogous to the loading cycle and subsequent localization or reactivation on brittle faults embedded in an elastic medium. Universally, rapid primary deformation arrests and transitions into a long secondary deformation phase that ultimately accelerates to catastrophic rupture. Primary deformation (u) conforms to Andrade's law as du/dt ~ (tc - t0)θ with a standard exponent of 2/3. In the long, and readily observable, secondary phase, the samples both deform and analogously shed load near linearly in time. This stress relaxation rate exhibits a robust power law dependency with time-to-rupture and exhibits the same 2/3 power law exponent observed in the primary phase. Similarly, the brittle strain energy released in the tertiary collapse scales with a normalized secondary stress relaxation rate. Together, these observations suggest a way to predict both the timing of rupture and its energetics from the observed stress (or strain) rate during the secondary relaxation stage.

  10. Circulating long non-coding RNAs NRON and MHRT as novel predictive biomarkers of heart failure.

    PubMed

    Xuan, Lina; Sun, Lihua; Zhang, Ying; Huang, Yuechao; Hou, Yan; Li, Qingqi; Guo, Ying; Feng, Bingbing; Cui, Lina; Wang, Xiaoxue; Wang, Zhiguo; Tian, Ye; Yu, Bo; Wang, Shu; Xu, Chaoqian; Zhang, Mingyu; Du, Zhimin; Lu, Yanjie; Yang, Bao Feng

    2017-03-14

    This study sought to evaluate the potential of circulating long non-coding RNAs (lncRNAs) as biomarkers for heart failure (HF). We measured the circulating levels of 13 individual lncRNAs which are known to be relevant to cardiovascular disease in the plasma samples from 72 HF patients and 60 non-HF control participants using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) methods. We found that out of the 13 lncRNAs tested, non-coding repressor of NFAT (NRON) and myosin heavy-chain-associated RNA transcripts (MHRT) had significantly higher plasma levels in HF than in non-HF subjects: 3.17 ± 0.30 versus 1.0 ± 0.07 for NRON (P < 0.0001) and 1.66 ± 0.14 versus 1.0 ± 0.12 for MHRT (P < 0.0001). The area under the ROC curve was 0.865 for NRON and 0.702 for MHRT. Univariate and multivariate analyses identified NRON and MHRT as independent predictors for HF. Spearman's rank correlation analysis showed that NRON was negatively correlated with HDL and positively correlated with LDH, whereas MHRT was positively correlated with AST and LDH. Hence, elevation of circulating NRON and MHRT predicts HF and may be considered as novel biomarkers of HF.

  11. Failure location prediction by finite element analysis for an additive manufactured mandible implant.

    PubMed

    Huo, Jinxing; Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-Michaél; Gamstedt, E Kristofer

    2015-09-01

    In order to reconstruct a patient with a bone defect in the mandible, a porous scaffold attached to a plate, both in a titanium alloy, was designed and manufactured using additive manufacturing. Regrettably, the implant fractured in vivo several months after surgery. The aim of this study was to investigate the failure of the implant and show a way of predicting the mechanical properties of the implant before surgery. All computed tomography data of the patient were preprocessed to remove metallic artefacts with metal deletion technique before mandible geometry reconstruction. The three-dimensional geometry of the patient's mandible was also reconstructed, and the implant was fixed to the bone model with screws in Mimics medical imaging software. A finite element model was established from the assembly of the mandible and the implant to study stresses developed during mastication. The stress distribution in the load-bearing plate was computed, and the location of main stress concentration in the plate was determined. Comparison between the fracture region and the location of the stress concentration shows that finite element analysis could serve as a tool for optimizing the design of mandible implants.

  12. Prediction of the Chemoreflex Gain by Common Clinical Variables in Heart Failure

    PubMed Central

    Mirizzi, Gianluca; Giannoni, Alberto; Ripoli, Andrea; Iudice, Giovanni; Bramanti, Francesca; Emdin, Michele; Passino, Claudio

    2016-01-01

    Background Peripheral and central chemoreflex sensitivity, assessed by the hypoxic or hypercapnic ventilatory response (HVR and HCVR, respectively), is enhanced in heart failure (HF) patients, is involved in the pathophysiology of the disease, and is under investigation as a potential therapeutic target. Chemoreflex sensitivity assessment is however demanding and, therefore, not easily applicable in the clinical setting. We aimed at evaluating whether common clinical variables, broadly obtained by routine clinical and instrumental evaluation, could predict increased HVR and HCVR. Methods and results 191 patients with systolic HF (left ventricular ejection fraction—LVEF—<50%) underwent chemoreflex assessment by rebreathing technique to assess HVR and HCVR. All patients underwent clinical and neurohormonal evaluation, comprising: echocardiogram, cardiopulmonary exercise test (CPET), daytime cardiorespiratory monitoring for breathing pattern evaluation. Regarding HVR, multivariate penalized logistic regression, Bayesian Model Averaging (BMA) logistic regression and random forest analysis identified, as predictors, the presence of periodic breathing and increased slope of the relation between ventilation and carbon dioxide production (VE/VCO2) during exercise. Again, the above-mentioned statistical tools identified as HCVR predictors plasma levels of N-terminal fragment of proBNP and VE/VCO2 slope. Conclusions In HF patients, the simple assessment of breathing pattern, alongside with ventilatory efficiency during exercise and natriuretic peptides levels identifies a subset of patients presenting with increased chemoreflex sensitivity to either hypoxia or hypercapnia. PMID:27099934

  13. Humidity sensor failure: a problem that should not be neglected by the numerical weather prediction community

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Tang, N.

    2014-07-01

    In this paper, a new issue that very low relative humidity observations exist in a deeper atmosphere layer in the low- and mid-troposphere is studied on the basis of the global radiosonde observations from December 2008 to November 2009, and the humidity retrieval productions from Formosa Satellite mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC, referred to as COSMIC hereafter) in the same period. Results show that these extremely dry relative humidity observations are considerable universal in the worldwide operational radiosonde data. Globally, the annual average occurrence probability of the extremely dry relative humidity is of 4.2%. These measurements usually occur between 20° and 40° latitudes in both Northern and Southern Hemispheres, and in the height from 700 to 450 hPa in the low- and mid-troposphere. Winter and spring are the favoured seasons for these extremely dry humidity observations, with the maximum ratio of 9.53% in the Northern Hemisphere and 16.82% in the Southern Hemisphere. The phenomenon is mainly related to the performance of the radiosonde humidity sensor and the cloud types traversed by the radiosonde balloon. These extremely low relative humidity observations are erroneous, which cannot represent the real atmospheric status, and are likely caused by the failure of humidity sensor. However, these observations have been archived as the formal data. It will affect the reliability of numerical weather prediction, the analysis of weather and climate, if the quality control procedure is not applied.

  14. TBCs for Gas Turbines under Thermomechanical Loadings: Failure Behaviour and Life Prediction

    NASA Astrophysics Data System (ADS)

    Beck, T.; Trunova, O.; Herzog, R.; Singheiser, L.

    2012-10-01

    The present contribution gives an overview about recent research on a thermal barrier coating (TBC) system consisted of (i) an intermetallic MCrAlY-alloy Bondcoat (BC) applied by vacuum plasma spraying (VPS) and (ii) an Yttria Stabilised Zirconia (YSZ) top coat air plasma sprayed (APS) at Forschungszentrum Juelich, Institute of Energy and Climate Research (IEK-1). The influence of high temperature dwell time, maximum and minimum temperature on crack growth kinetics during thermal cycling of such plasma sprayed TBCs is investigated using infrared pulse thermography (IT), acoustic emission (AE) analysis and scanning electron microscopy. Thermocyclic life in terms of accumulated time at maximum temperature decreases with increasing high temperature dwell time and increases with increasing minimum temperature. AE analysis proves that crack growth mainly occurs during cooling at temperatures below the ductile-to-brittle transition temperature of the BC. Superimposed mechanical load cycles accelerate delamination crack growth and, in case of sufficiently high mechanical loadings, result in premature fatigue failure of the substrate. A life prediction model based on TGO growth kinetics and a fracture mechanics approach has been developed which accounts for the influence of maximum and minimum temperature as well as of high temperature dwell time with good accuracy in an extremely wide parameter range.

  15. Relationship between pre-extubation positive endexpiratory pressure and oxygenation after coronary artery bypass grafting

    PubMed Central

    Lima, Reijane Oliveira; Borges, Daniel Lago; Costa, Marina de Albuquerque Gonçalves; Baldez, Thiago Eduardo Pereira; Silva, Mayara Gabrielle Barbosa e; Sousa, Felipe André Silva; Soares, Milena de Oliveira; Pinto, Jivago Gentil Moreira

    2015-01-01

    Introduction After removal of endotracheal tube and artificial ventilation, ventilatory support should be continued, offering oxygen supply to ensure an arterial oxygen saturation close to physiological. Objective The aim of this study was to investigate the effects of positive-end expiratory pressure before extubation on the oxygenation indices of patients undergoing coronary artery bypass grafting. Methods A randomized clinical trial with seventy-eight patients undergoing coronary artery bypass grafting divided into three groups and ventilated with different positive-end expiratory pressure levels prior to extubation: Group A, 5 cmH2O (n=32); Group B, 8 cmH2O (n=26); and Group C, 10 cmH2O (n=20). Oxygenation index data were obtained from arterial blood gas samples collected at 1, 3, and 6 h after extubation. Patients with chronic pulmonary disease and those who underwent off-pump, emergency, or combined surgeries were excluded. For statistical analysis, we used Shapiro-Wilk, G, Kruskal-Wallis, and analysis of variance tests and set the level of significance at P<0.05. Results Groups were homogenous with regard to demographic, clinical, and surgical variables. There were no statistically significant differences between groups in the first 6 h after extubation with regard to oxygenation indices and oxygen therapy utilization. Conclusion In this sample of patients undergoing coronary artery bypass grafting, the use of different positive-end expiratory pressure levels before extubation did not affect gas exchange or oxygen therapy utilization in the first 6 h after endotracheal tube removal. PMID:27163418

  16. Central venous catheter tip migration due to tracheal extubation: a prospective randomized study.

    PubMed

    Struck, Manuel F; Jünemann, Theresa; Reinhart, Konrad; Schummer, Wolfram

    2016-07-28

    Considerable numbers of patients undergo central venous catheterization (CVC) under mechanical ventilation. We hypothesized that the return of spontaneous breathing and tracheal extubation could be associated with distal CVC tip migration towards intracardiac positions due to decreasing intrathoracic pressures and subsequent readjustment of mediastinal organs. Patients scheduled for cardiac surgery were randomized for right or left internal jugular vein (IJV) CVC placement under general anesthesia and mechanical ventilation. CVC tips were positioned at the cavoatrial junction and measured at the time of placement, postoperatively under mechanical ventilation, and after tracheal extubation until 48 h after surgery. Measurement methods included intravascular electrocardiography (ECG) P-wave amplitude, transesophageal echocardiography, and chest radiography (CXR). Out of 70 patients, 60 were eligible for final statistical analysis (31 right and 29 left IJV CVC). According to ECG interpretation, CVC tip positions remained below the pericardiac reflection point in the distal superior vena cava over the course of the three measurement intervals. The ECG revealed significant proximal migration of CVC tips from the time of placement to the time of tracheal extubation (1.19 ± 0.55 vs. 0.62 ± 0.31 mV; P < 0.001). A CXR using CVC tip to carina distances revealed no significant tip migrations in the time between postoperative assessment and following tracheal extubation (5.1 ± 1.7 vs. 5.3 ± 1.5 cm; P = 0.196). In patients with CVCs positioned at the cavoatrial junction, tracheal extubation was not associated with significant postoperative CVC tip malposition, but tended to undergo proximal migration. This trend should be considered particularly in left-sided thoracocervical puncture approaches to avoid unfavorable CVC tip positions.

  17. Lamivudine Concentration in Hair and Prediction of Virologic Failure and Drug Resistance among HIV Patients Receiving Free ART in China

    PubMed Central

    Wang, Zhe; Wu, Jianjun; Zhang, Jiafeng; Ruan, Yuhua; Hsi, Jenny; Liao, Lingjie; Shao, Yiming; Xing, Hui

    2016-01-01

    Background The assessment of adherence to antiretroviral therapy (ART) is important in order to predict treatment outcomes. Lamivudine (3TC) is one of the most widely used NRTIs in China, but its concentrations in hair and association with virologic failure and drug resistance have not been studied. Methods We conducted a cross-sectional survey to investigate 3TC concentrations in hair as a predictor of virologic failure and drug resistance among HIV patients receiving free ART. We also compared the capacity of hair 3TC concentrations with self-reported adherence in predicting virologic responses. Hair 3TC concentrations were detected through the LC-MS/MS system. Results In patients without HIV drug resistance (HIVDR), with a threshold hair 3TC concentration of 260 ng/g, the sensitivity and specificity in predicting virologic suppression were 76.9% and 89.9%, respectively. Some factors, including CD4+ cell counts, initial treatment regimens with 3TC, and current regimens with second-line drugs, influenced the association between hair 3TC concentrations and virologic suppression. In patients who experienced virologic failure with HIVDR, with a threshold of 180 ng/g, the sensitivity and specificity were 70.0% and 74.4%, respectively. Hair 3TC concentrations had higher sensitivity and specificity in predicting virologic failure and drug resistance than self-reported adherence. Conclusions The hair 3TC concentration was a stronger indicator than self-reported adherence in predicting virologic failure and drug resistance in HIV patients receiving free ART. PMID:27119346

  18. Implementation of Predictive Data Mining Techniques for Identifying Risk Factors of Early AVF Failure in Hemodialysis Patients

    PubMed Central

    Rezapour, Mohammad; Khavanin Zadeh, Morteza; Sepehri, Mohammad Mehdi

    2013-01-01

    Arteriovenous fistula (AVF) is an important vascular access for hemodialysis (HD) treatment but has 20–60% rate of early failure. Detecting association between patient's parameters and early AVF failure is important for reducing its prevalence and relevant costs. Also predicting incidence of this complication in new patients is a beneficial controlling procedure. Patient safety and preservation of early AVF failure is the ultimate goal. Our research society is Hasheminejad Kidney Center (HKC) of Tehran, which is one of Iran's largest renal hospitals. We analyzed data of 193 HD patients using supervised techniques of data mining approach. There were 137 male (70.98%) and 56 female (29.02%) patients introduced into this study. The average of age for all the patients was 53.87 ± 17.47 years. Twenty eight patients had smoked and the number of diabetic patients and nondiabetics was 87 and 106, respectively. A significant relationship was found between “diabetes mellitus,” “smoking,” and “hypertension” with early AVF failure in this study. We have found that these mentioned risk factors have important roles in outcome of vascular surgery, versus other parameters such as “age.” Then we predicted this complication in future AVF surgeries and evaluated our designed prediction methods with accuracy rates of 61.66%–75.13%. PMID:23861725

  19. Predicting treatment failure in patients with community acquired pneumonia: a case-control study

    PubMed Central

    2014-01-01

    Introduction Treatment failure in community-acquired-pneumonia (CAP) patients is associated with a high mortality rate, and therefore are a matter of great concern in clinical management. Those patients have increased mortality and are a target population for randomized clinical trials. Methods A case–control study was performed in patients with CAP (non-failure cases vs. failure cases, discriminating by late and early failure). CRP, PCT, interleukin 1, 6, 8 and 10 and TNF were determined at days 1 and 3 of hospitalization. Results A total of 253 patients were included in this study where 83 patients presented treatment failure. Of these, 40 (48.2%) had early failure. A discriminative effect was found for a higher CURB-65 score among late failure patients (p = 0.004). A significant increase on day 1 of hospitalization in CRP (p < 0.001), PCT (p = 0.004), IL-6 (p < 0.001) and IL-8 (p = 0.02), and a decrease in IL-1 (p = 0.06) in patients with failure was observed compared with patients without failure. On day 3, only the increase in CRP (p < 0.001), PCT (p = 0.007) and IL-6 (p < 0.001) remained significant. Independent predictors for early failure were higher IL-6 levels on day 1 (OR = 1.78, IC = 1.2-2.6) and pleural effusion (OR = 2.25, IC = 1.0-5.3), and for late failure, higher PCT levels on day 3 (OR = 1.60, IC = 1.0-2.5), CURB-65 score ≥ 3 (OR = 1.43, IC = 1.0-2.0), and multilobar involvement (OR = 4.50, IC = 2.1-9.9). Conclusions There was a good correlation of IL-6 levels and CAP failure and IL-6 & PCT with late CAP failure. Pleural effusion and multilobar involvement were simple clinical predictors of early and late failure, respectively. Trial registration IRB Register: http://2009/5451. PMID:24996572

  20. Elevated troponin T on discharge predicts poor outcome of decompensated heart failure.

    PubMed

    Koide, Kimi; Yoshikawa, Tsutomu; Nagatomo, Yuji; Kohsaka, Shun; Anzai, Toshihisa; Meguro, Tomomi; Ogawa, Satoshi

    2010-05-01

    Persistent elevation of cardiac troponin T (cTnT) predicts an adverse clinical outcome in patients with chronic heart failure (HF), but the underlying mechanisms remain to be determined. We investigated the association between predischarge cTnT elevation and coexistent pathophysiology in patients with decompensated HF. Plasma cTnT levels were determined before discharge in 170 patients with decompensated HF. We divided the patients into a group that was positive for cTnT [cTnT(+) group, n = 40] and a group that was negative for cTnT [cTnT(-) group, n = 130]. Multivariate analysis showed that use of beta-blocker therapy (odds ratio [OR] = 0.236, P = 0.003), an elevated high-sensitivity C-reactive protein (hsCRP) level (OR = 3.731, P = 0.006), a high brain natriuretic peptide (BNP) level (OR = 3.570, P = 0.007), diabetes (OR = 3.090, P = 0.018), and anemia (OR = 2.330, P = 0.047) were independently associated with cTnT positivity. During a mean follow-up period of 441 days after discharge, total mortality (P < 0.001), cardiac death (P < 0.001), and exacerbation of HF requiring hospitalization (P = 0.007) were all more common in the cTnT(+) group than in the cTnT(-) group. Cox proportional hazards analysis showed that cTnT positivity was an independent predictor of total mortality (hazard ratio = 5.008, P = 0.004) in an age- and gender-matched model. Elevation of cTnT during convalescence was associated with lack of beta-blocker therapy, a high hsCRP level at discharge, a high BNP level at discharge, diabetes, and anemia, and a worse clinical outcome in patients with decompensated HF.

  1. Predicting Right Ventricular Failure in the Modern, Continuous Flow Left Ventricular Assist Device Era

    PubMed Central

    Atluri, Pavan; Goldstone, Andrew B.; Fairman, Alex S.; MacArthur, John W.; Shudo, Yasuhiro; Cohen, Jeffrey E.; Acker, Alexandra L.; Hiesinger, William; Howard, Jessica L.; Acker, Michael A.; Woo, Y. Joseph

    2014-01-01

    Background In the era of destination continuous flow left ventricular assist devices (LVAD), the decision of whether a patient will tolerate isolated LVAD support or will need biventricular support (BIVAD) can be challenging. Incorrect decision making with delayed right ventricular (RV) assist device implantation results in increased morbidity and mortality. Continuous flow LVADs have been shown to decrease pulmonary hyper-tension and improve RV function. We undertook this study to determine predictors in the continuous flow LVAD era that identify patients who are candidates for isolated LVAD therapy as opposed to biventricular support. Methods We reviewed demographic, hemodynamic, laboratory, and echocardiographic variables for 218 patients who underwent VAD implant from 2003 through 2011 (LVAD = 167, BIVAD = 51), during the era of continuous flow LVADs. Results Fifty preoperative risk factors were compared between patients who were successfully managed with an LVAD and those who required a BIVAD. Seventeen variables demonstrated statistical significance by univariate analysis. Multivariable logistic regression analysis identified central venous pressure >15 mmHg (OR 2.0, “C”), severe RV dysfunction (OR 3.7, “R”), preoperative intubation (OR 4.3, “I”), severe tricuspid regurgitation (OR 4.1, “T”), heart rate >100 (OR 2.0, Tachycardia - “T”) -CRITT as the major criteria predictive of the need for biventricular support. Utilizing these data, a highly sensitive and easy to use risk score for determining RV failure was generated that outperformed other established risk stratification tools. Conclusions We present a preoperative risk calculator to determine suitability of a patient for isolated LVAD support in the current continuous flow ventricular assist device era. PMID:23791165

  2. The Change in Body Weight During Hospitalization Predicts Mortality in Patients With Acute Decompensated Heart Failure

    PubMed Central

    Komaki, Tomo; Miura, Shin-ichiro; Arimura, Tadaaki; Shiga, Yuhei; Morii, Joji; Kuwano, Takashi; Imaizumi, Satoshi; Kitajima, Ken; Iwata, Atsushi; Morito, Natsumi; Yahiro, Eiji; Fujimi, Kanta; Matsunaga, Akira; Saku, Keijiro

    2017-01-01

    Background In our experience, the change in body weight (BW) during hospitalization varies greatly in patients with acute decompensated heart failure (HF). Since the clinical significance of a change in BW is not clear, we investigated whether a change in BW could predict mortality. Methods We retrospectively enrolled 130 patients (72 males; aged 68 ± 10 years) who were hospitalized due to acute decompensated HF and followed for 2 years after discharge. The change in the BW index during hospitalization (ΔBWI) was calculated as (BW at hospital admission minus BW at hospital discharge)/body surface area at hospital discharge. Results The patients were divided into quartiles according to ΔBWI, and the 2-year mortality rates in the quartiles with the lowest, second, third and highest ΔBWI were 18.8%, 12.1%, 3.1% and 9.1%, respectively. In a multivariate Cox proportional hazards analysis after adjusting for variables with a P value less than 0.05, ΔBWI was independently associated with 2-year mortality (P = 0.0002), and the quartile with the lowest ΔBWI had a higher relative risk (RR) for 2-year mortality than the quartile with the highest ΔBWI (RR: 7.46, 95% confidence interval: 1.03 - 53.99, P = 0.04). Conclusion In conclusion, ΔBWI was significantly associated with 2-year mortality after discharge, which indicates that ΔBWI might be a simple predictor of prognosis in acute decompensated HF. PMID:28179967

  3. The role of microstructure and phase distribution in the failure mechanisms and life prediction model for PSZ coatings

    NASA Technical Reports Server (NTRS)

    Sisson, R. D., Jr.; Sone, Ichiro; Biederman, R. R.

    1985-01-01

    Partially Stabilized Zirconia (PSZ) may become widely used for Thermal Barrier Coatings (TBC). Failure of these coatings can occur due to thermal fatigue in oxidizing atmospheres. The failure is due to the strains that develop due to thermal gradients, differences in thermal expansion coefficients, and oxidation of the bond coating. The role of microstructure and the cubic, tetragonal, and monoclinic phase distribution in the strain development and subsequent failure will be discussed. An X-ray diffraction technique for accurate determination of the fraction of each phase in PSZ will be applied to understanding the phase transformations and strain development. These results will be discussed in terms of developing a model for life prediction in PSZ coatings during thermal cycling.

  4. Predicting the Velocity and Azimuth of Fragments Generated by the Range Destruction or Random Failure of Rocket Casings and Tankage

    SciTech Connect

    Eck, Marshall B.; Mukunda, Meera

    1988-10-01

    The details of a predictive analytical modeling process as well as the development of normalized relations for momentum partition as a function of SRM burn time and initial geometry are discussed in this paper. Methods for applying similar modeling techniques to liquid-tankage-over-pressure failures are also discussed. These methods have been calibrated against observed SRM ascent failures and on-orbit tankage failures. Casing-quadrant sized fragments with velocities exceeding 100 m/s resulted from Titan 34D-SRM range destruct actions at 10 sec mission elapsed time (MET). Casing-quadrant sized fragments with velocities of approximately 200 m/s resulted from STS-SRM range destruct actions at 110 sec MET. Similar sized fragments for Ariane third stage and Delta second stage tankage were predicted to have maximum velocities of 260 m/s and 480 m/s respectively. Good agreement was found between the predictions and observations for five specific events and it was concluded that the methods developed have good potential for use in predicting the fragmentation process of a number of generically similar casing and tankage systems. There are three copies in the file, one of these is loose.

  5. Pitfalls and Precautions When Using Predicted Failure Data for Quantitative Analysis of Safety Risk for Human Rated Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Hatfield, Glen S.; Hark, Frank; Stott, James

    2016-01-01

    Launch vehicle reliability analysis is largely dependent upon using predicted failure rates from data sources such as MIL-HDBK-217F. Reliability prediction methodologies based on component data do not take into account system integration risks such as those attributable to manufacturing and assembly. These sources often dominate component level risk. While consequence of failure is often understood, using predicted values in a risk model to estimate the probability of occurrence may underestimate the actual risk. Managers and decision makers use the probability of occurrence to influence the determination whether to accept the risk or require a design modification. The actual risk threshold for acceptance may not be fully understood due to the absence of system level test data or operational data. This paper will establish a method and approach to identify the pitfalls and precautions of accepting risk based solely upon predicted failure data. This approach will provide a set of guidelines that may be useful to arrive at a more realistic quantification of risk prior to acceptance by a program.

  6. Patency of Femoral Tunneled Hemodialysis Catheters and Factors Predictive of Patency Failure

    SciTech Connect

    Burton, Kirsteen R.; Guo, Lancia L. Q.; Tan, Kong T.; Simons, Martin E.; Sniderman, Kenneth W.; Kachura, John R.; Beecroft, John R.; Rajan, Dheeraj K.

    2012-12-15

    Purpose: To determine the patency rates of and factors associated with increased risk of patency failure in patients with femoral vein tunneled hemodialysis catheters. Methods: All femoral tunneled catheter insertions from 1996 to 2006 were reviewed, during which time 123 catheters were inserted. Of these, 66 were exchanges. Patients with femoral catheter failure versus those with femoral catheter patency were compared. Confounding factors, such as demographic and procedural factors, were incorporated and assessed using univariate and multivariable Cox proportional hazards regression analyses. Results: Mean catheter primary patency failure time was 96.3 days (SE 17.9 days). Primary patency at 30, 60, 90, and 180 days was 53.8%, 45.4%, 32.1%, and 27.1% respectively. Crude rates of risk of catheter failure did not suggest a benefit for patients receiving catheters introduced from one side versus the other, but more cephalad location of catheter tip was associated with improved patency. Multivariate analysis showed that patients whose catheters were on the left side (p = 0.009), were of increasing age at the time of insertion (p = 0.002) and that those who had diabetes (p = 0.001) were at significantly greater risk of catheter failure. The catheter infection rate was 1.4/1000 catheter days. Conclusion: Patients who were of a more advanced age and had diabetes were at greater risk of femoral catheter failure, whereas those who received femoral catheters from the right side were less at risk of catheter failure.

  7. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion.

    PubMed

    Jackman, Timothy M; DelMonaco, Alex M; Morgan, Elise F

    2016-01-25

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (μCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7-T9, n=28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12-279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms.

  8. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion

    PubMed Central

    Jackman, Timothy M.; DelMonaco, Alex M.; Morgan, Elise F.

    2016-01-01

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (µCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7–T9, n = 28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12–279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms. PMID:26792288

  9. Two-phase damage theory and crustal rock failure: the theoretical `void' limit, and the prediction of experimental data

    NASA Astrophysics Data System (ADS)

    Ricard, Yanick; Bercovici, David

    2003-12-01

    Using a classical averaging approach, we derive a two-phase theory to describe the deformation of a porous material made of a matrix containing voids. The presence and evolution of surface energy at the interface between the solid matrix and voids is taken into account with non-equilibrium thermodynamic considerations that allow storage of deformational work as surface energy on growing or newly created voids. This treatment leads to a simple description of isotropic damage that can be applied to low-cohesion media such as sandstone. In particular, the theory yields two possible solutions wherein samples can either `break' by shear localization with dilation (i.e. void creation), or undergo shear-enhanced compaction (void collapse facilitated by deviatoric stress). For a given deviatoric stress and confining pressure, the dominant solution is that with the largest absolute value of the dilation rate, |Γ|, which thus predicts that shear-localization and dilation occur at low effective pressures, while shear-enhanced compaction occurs at larger effective pressure. Stress trajectories of constant |Γ| represent potential failure envelopes that are ogive- (Gothic-arch-) shaped curves, wherein the ascending branch represents failure by dilation and shear-localization, and the descending branch denotes shear-enhanced compactive failure. The theory further predicts that the onset of dilation preceding shear-localization and failure necessarily occurs at the transition from compactive to dilational states and thus along a line connecting the peaks of constant-|Γ| ogives. Finally, the theory implies that while shear-enhanced compaction first occurs with increasing deviatoric stress (at large effective pressure), dilation will occur at higher deviatoric stresses. All of these predictions in fact compare very successfully with various experimental data. Indeed, the theory leads to a normalization where all the data of failure envelopes and dilation thresholds collapse to a

  10. Health literacy and global cognitive function predict e-mail but not internet use in heart failure patients.

    PubMed

    Schprechman, Jared P; Gathright, Emily C; Goldstein, Carly M; Guerini, Kate A; Dolansky, Mary A; Redle, Joseph; Hughes, Joel W

    2013-01-01

    Background. The internet offers a potential for improving patient knowledge, and e-mail may be used in patient communication with providers. However, barriers to internet and e-mail use, such as low health literacy and cognitive impairment, may prevent patients from using technological resources. Purpose. We investigated whether health literacy, heart failure knowledge, and cognitive function were related to internet and e-mail use in older adults with heart failure (HF). Methods. Older adults (N = 119) with heart failure (69.84 ± 9.09 years) completed measures of health literacy, heart failure knowledge, cognitive functioning, and internet use in a cross-sectional study. Results. Internet and e-mail use were reported in 78.2% and 71.4% of this sample of patients with HF, respectively. Controlling for age and education, logistic regression analyses indicated that higher health literacy predicted e-mail (P < .05) but not internet use. Global cognitive function predicted e-mail (P < .05) but not internet use. Only 45% used the Internet to obtain information on HF and internet use was not associated with greater HF knowledge. Conclusions. The majority of HF patients use the internet and e-mail, but poor health literacy and cognitive impairment may prevent some patients from accessing these resources. Future studies that examine specific internet and email interventions to increase HF knowledge are needed.

  11. Deformation, Failure, and Fatigue Life of SiC/Ti-15-3 Laminates Accurately Predicted by MAC/GMC

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2002-01-01

    NASA Glenn Research Center's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) (ref.1) has been extended to enable fully coupled macro-micro deformation, failure, and fatigue life predictions for advanced metal matrix, ceramic matrix, and polymer matrix composites. Because of the multiaxial nature of the code's underlying micromechanics model, GMC--which allows the incorporation of complex local inelastic constitutive models--MAC/GMC finds its most important application in metal matrix composites, like the SiC/Ti-15-3 composite examined here. Furthermore, since GMC predicts the microscale fields within each constituent of the composite material, submodels for local effects such as fiber breakage, interfacial debonding, and matrix fatigue damage can and have been built into MAC/GMC. The present application of MAC/GMC highlights the combination of these features, which has enabled the accurate modeling of the deformation, failure, and life of titanium matrix composites.

  12. KLIC-score for predicting early failure in prosthetic joint infections treated with debridement, implant retention and antibiotics.

    PubMed

    Tornero, E; Morata, L; Martínez-Pastor, J C; Bori, G; Climent, C; García-Velez, D M; García-Ramiro, S; Bosch, J; Mensa, J; Soriano, A

    2015-08-01

    Debridement, irrigation and antibiotic treatment form the current approach in early prosthetic joint infection (PJI). Our aim was to design a score to predict patients with a higher risk of failure. From 1999 to 2014 early PJIs were prospectively collected and retrospectively reviewed. The primary end-point was early failure defined as: 1) the need for unscheduled surgery, 2) death-related infection within the first 60 days after debridement or 3) the need for suppressive antibiotic treatment. A score was built-up according to the logistic regression coefficients of variables available before debridement. A total of 222 patients met the inclusion criteria. The most frequently isolated microorganisms were coagulase-negative staphylococci (95 cases, 42.8%) and Staphylococcus aureus (81 cases, 36.5%). Treatment of 52 (23.4%) cases failed. Independent predictors of failure were: chronic renal failure (OR 5.92, 95% CI 1.47-23.85), liver cirrhosis (OR 4.46, 95% CI 1.15-17.24), revision surgery (OR 4.34, 95% CI 1.34-14.04) or femoral neck fracture (OR 4.39, 95% CI1.16-16.62) compared with primary arthroplasty, C reactive protein >11.5 mg/dL (OR 12.308, 95% CI 4.56-33.19), cemented prosthesis (OR 8.71, 95% CI 1.95-38.97) and when all intraoperative cultures were positive (OR 6.30, 95% CI 1.84-21.53). A score for predicting the risk of failure was designed using preoperative factors (KLIC-score: Kidney, Liver, Index surgery, Cemented prosthesis and C-reactive protein value) and it ranged between 0 and 9.5 points. Patients with scores of ≤2, >2-3.5, 4-5, >5-6.5 and ≥7 had failure rates of 4.5%, 19.4%, 55%, 71.4% and 100%, respectively. The KLIC-score was highly predictive of early failure after debridement. In the future, it would be necessary to validate our score using cohorts from other institutions.

  13. A longitudinal linear model of patient characteristics to predict failure to attend an inner-city chronic pain clinic

    PubMed Central

    Shaparin, N; White, RS; Andreae, MH; Hall, CB; Kaufman, AG

    2014-01-01

    Patients often fail to attend appointments in chronic pain clinics for unknown reasons. We hypothesized that certain patient characteristics predict failure to attend scheduled appointments pointing to systematic barriers to access chronic pain services for certain underserved populations. We collected retrospective data from a longitudinal observational cohort of patients at an academic pain clinic in Newark, New Jersey. To examine the effect of demographic factors on appointment status, we fit a marginal logistic regression using generalized estimating equations with exchangeable correlation. 1394 patients with 3488 total encounters between January 1, 2006 and December 31, 2009 were included. Spanish spoken as a primary language (alternatively Hispanic or other race) and living between five and ten miles from the clinic were associated with reduced odds of arriving for an appointment; making an appointment for a particular complaint such as cancer pain or back pain, an interventional pain procedure scheduled in connection with the appointment, unemployed status, and continuity of care (as measured by office visit number) were associated with increased odds of arriving. Spanish spoken as primary language and distance to the pain clinic predicted failure to attend a scheduled appointment in our cohort. If these constitute systematic barriers to access, they may be amendable to targeted interventions. Perspective We identified certain patient characteristics, specifically Spanish spoken as primary language and geographic distance from the clinic, that predict failure to attend an inner-city chronic pain clinic. These identified barriers to access chronic pain services may be modifiable by simple cost effective interventions. PMID:24747766

  14. Prediction of risk of diabetic retinopathy for all-cause mortality, stroke and heart failure

    PubMed Central

    Zhu, Xiao-Rong; Zhang, Yong-Peng; Bai, Lu; Zhang, Xue-Lian; Zhou, Jian-Bo; Yang, Jin-Kui

    2017-01-01

    Abstract To examine and quantify the potential relation between diabetic retinopathy (DR) and risk of all-cause mortality, stroke and heart failure (HF). The resources of meta-analysis of epidemiological observational studies were from Pub-med, EMBASE, CINAHL, Cochrane Library, conference, and proceedings. Random/fixed effects models were used to calculate pooled subgroup analysis stratified by different grades of DR was performed to explore the potential source of heterogeneity. Statistical manipulations were undertaken using program STATA. Of the included 25 studies, comprising 142,625 participants, 19 studies were concluded to find the relation of DR to all-cause mortality, 5 for stroke, and 3 for HF. Risk ratio (RR) for all-cause mortality with the presence of DR was 2.33 (95% CI 1.92–2.81) compared with diabetic individuals without DR. Evidences showed a higher risk of all-cause mortality associated with DR in patients with T2D or T1D (RR 2.25, 95% CI 1.91–2.65. RR 2.68, 95% CI 1.34–5.36). According to different grades of DR in patients with T2D, RR for all-cause mortality varied, the risk of nonproliferative diabetic retinopathy (NPDR) was 1.38 (1.11–1.70), while the risk of proliferative diabetic retinopathy (PDR) was 2.32 (1.75–3.06). There was no evidence of significant heterogeneity (Cochran Q test P = 0.29 vs 0.26, I2 = 19.6% vs 22.6%, respectively). Data from 5 studies in relation to DR and the risk of stroke showed that DR was significantly associated with increased risk of stroke (RR = 1.74, 95%CI: 1.35–2.24), compared with patients without DR. Furthermore, DR (as compared with individuals without DR) was associated with a marginal increased risk of HF in patients with diabetes mellitus (DM) (n = 3 studies; RR 2.24, 95% CI 0.98–5.14, P = 0.056). Our results showed that DR increased the risk of all-cause mortality, regardless of the different stages, compared with the diabetic individuals without DR. DR predicted

  15. Rapid and reliable smooth extubation – Comparison of fentanyl with dexmedetomidine: A randomized, double-blind clinical trial

    PubMed Central

    Rani, P.; Hemanth Kumar, V. R.; Ravishankar, M.; Sivashanmugam, T.; Sripriya, R.; Trilogasundary, M.

    2016-01-01

    Background: Fentanyl and dexmedetomidine have been tried to attenuate airway and circulatory reflexes during emergence and extubation individually but have not been compared with respect to the level of sedation to evolve a reliable technique for rapid and smooth extubation. Aim: To compare the effects of fentanyl and dexmedetomidine in attenuating airway and circulatory reflexes during emergence and extubation of the endotracheal tube. Setting and Design: This double-blind, randomized, controlled study was done in patients undergoing surgery under general anesthesia belonging to the American Society of Anesthesiologists physical status 1 or 2. Methodology: All patients received a standardized anesthetic protocol. Patients were randomized to receive either fentanyl 1 μg/kg or dexmedetomidine 0.75 μg/kg. Fifteen minutes before expected last surgical suture, isoflurane was cutoff and equal amount of test solution was given when train-of-four ratio was 0.3. The degree of sedation, airway, and circulatory responses at the time of suction and extubation were analyzed. Statistical Analysis Used: Chi-square test for nonparametric data and t-test for parametric data. Results: Heart rate (HR) was comparable in both the groups until endotracheal extubation. Later, there was rise in HR in fentanyl group. There was stastisticaly significant drop in blood pressure at 5 min after test drug administration in both the groups. Airway response for suctioning and extubation was better in dexmedetomidine group and it was associated with better sedation score than fentanyl group. Conclusion: Single dose of 0.75 μg/kg dexmedetomidine given 15 min before extubation provides smooth extubation when compared to fentanyl. PMID:27746558

  16. Predictive value of dobutamine echocardiography and positron emission tomography in identifying hibernating myocardium in patients with postischaemic heart failure

    PubMed Central

    Pagano, D; Bonser, R; Townend, J; Ordoubadi, F; Lorenzoni, R; Camici, P

    1998-01-01

    Objective—To compare the predictive value of dobutamine echocardiography (DE) and positron emission tomography (PET) in identifying reversible chronic left ventricular (LV) dysfunction (hibernating myocardium) in patients with coronary artery disease (CAD) and overt heart failure.
Patients—30 patients (four women) with CAD and heart failure undergoing coronary artery bypass grafting (CABG).
Methods—Myocardial viability was assessed with DE (5 and 10 µg/kg/min) and PET with [18F] 2-fluoro-2-deoxy-D-glucose (FDG) under hyperinsulinaemic euglycaemic clamp. Regional (echo) and global LV function (MUGA) were assessed at baseline and six months after CABG.
Results—192 of the 336 (57%) dysfunctional LV segments improved function following CABG (hibernating) and the LV ejection fraction (EF) increased from 23(7) to 32(9)% (p < 0.0001) (in 17 patients > 5%). DE and PET had similar positive predictive values (68% and 66%) in the identification of hibernating myocardium, but DE had a significantly lower negative predictive value than PET (54% v 96%; p < 0.0001). A significant linear correlation was found between the number of PET viable segments and the changes in EF following CABG (r = 0.65; p = 0.0001). Stepwise logistic regression identified the number of PET viable segments as an independent predictor of improvement in EF > 5%, whereas the number of DE viable segments, the baseline LVEF, and wall motion were not.
Conclusions—DE has a higher false negative rate than PET in identifying recoverable LV dysfunction in patients with severe postischaemic heart failure. The amount of PET viable myocardium correlates with the functional outcome following CABG.

 Keywords: dobutamine echocardiography;  positron emission tomography;  coronary artery disease;  heart failure;  hibernating myocardium PMID:9602663

  17. Predictive factors for renal failure and a control and treatment algorithm

    PubMed Central

    Cerqueira, Denise de Paula; Tavares, José Roberto; Machado, Regimar Carla

    2014-01-01

    Objectives to evaluate the renal function of patients in an intensive care unit, to identify the predisposing factors for the development of renal failure, and to develop an algorithm to help in the control of the disease. Method exploratory, descriptive, prospective study with a quantitative approach. Results a total of 30 patients (75.0%) were diagnosed with kidney failure and the main factors associated with this disease were: advanced age, systemic arterial hypertension, diabetes mellitus, lung diseases, and antibiotic use. Of these, 23 patients (76.6%) showed a reduction in creatinine clearance in the first 24 hours of hospitalization. Conclusion a decline in renal function was observed in a significant number of subjects, therefore, an algorithm was developed with the aim of helping in the control of renal failure in a practical and functional way. PMID:26107827

  18. On the development of life prediction methodologies for the failure of human teeth

    SciTech Connect

    Nalla, R.K.; Imbeni, V.; Kinney, J.H.; Marshall, S.J.; Ritchie, R.O.

    2002-09-18

    Human dentin is known to be susceptible to failure under cyclic loading. Surprisingly, there are few reports that quantify the effect of such loading, considering the fact that a typical tooth experiences a million or so loading cycles annually. In the present study, a systematic investigation is described of the effects of prolonged cyclic loading on human dentin in a simulated physiological environment. In vitro stress-life (S/N) data are discussed in the context of possible mechanisms of fatigue damage and failure.

  19. A comparative study of early and late extubation following transoral odontoidectomy and posterior fixation

    PubMed Central

    Marda, Manish; Pandia, Mihir Prakash; Rath, Girija Prasad; Kale, Shashank Sharad; Dash, Harihara

    2016-01-01

    Background and Aims: Elective ventilation is the usual practice after transoral odontoidectomy (TOO) and posterior fixation. This practice of elective ventilation is not based on any evidence. The primary objective of our study was to find out the difference in oxygenation and ventilation in patients extubated early compared to those extubated late after TOO and posterior fixation. The secondary objectives were to compare the length of Intensive Care Unit (ICU)/hospital stay and pulmonary complications between the two groups. Material and Methods: After TOO and posterior fixation, patients were either extubated in the operating room (Group E) or extubated next day (Group D). The oxygenation (PaO2:FiO2 ratio) and ventilation (PaCO2) of the two groups before surgery, at 30 min and at 6/12/24 and 48 h after extubation were compared. Complications, durations of ICU and hospital stay were noted. Results: The base-line PaO2:FiO2 and PaCO2 was comparable between the groups. No significant change in the PaO2:FiO2 was noted in the postoperative period in either group as compared to the preoperative values. Except for at 12 h after surgery, there was no significant difference between the two groups at various time intervals. No significant change in the PaCO2 level was seen during the study period in either group. PaCO2 measured at 30 min after surgery was more in Group E (37.5 ± 3.2 mmHg in Group E vs. 34.6 ± 2.9 mmHg in Group D), otherwise there was no significant difference between the two groups at various time intervals. One patient in Group E (7.1%) and two patients in Group D (13%) developed postoperative respiratory complication, but the difference was not statistically significant. The mean ICU stay (Group D = 42 ± 25 h vs. Group E = 25.1 ± 16.9 h) and mean hospital stay (Group D = 9.9 ± 4 days vs. Group E = 7.6 ± 2.2 days) were longer in Group D patients. Conclusion: Ventilation and oxygenation in the postoperative period in patients undergoing TOO and

  20. Seismic energy data analysis of Merapi volcano to test the eruption time prediction using materials failure forecast method (FFM)

    NASA Astrophysics Data System (ADS)

    Anggraeni, Novia Antika

    2015-04-01

    The test of eruption time prediction is an effort to prepare volcanic disaster mitigation, especially in the volcano's inhabited slope area, such as Merapi Volcano. The test can be conducted by observing the increase of volcanic activity, such as seismicity degree, deformation and SO2 gas emission. One of methods that can be used to predict the time of eruption is Materials Failure Forecast Method (FFM). Materials Failure Forecast Method (FFM) is a predictive method to determine the time of volcanic eruption which was introduced by Voight (1988). This method requires an increase in the rate of change, or acceleration of the observed volcanic activity parameters. The parameter used in this study is the seismic energy value of Merapi Volcano from 1990 - 2012. The data was plotted in form of graphs of seismic energy rate inverse versus time with FFM graphical technique approach uses simple linear regression. The data quality control used to increase the time precision employs the data correlation coefficient value of the seismic energy rate inverse versus time. From the results of graph analysis, the precision of prediction time toward the real time of eruption vary between -2.86 up to 5.49 days.

  1. Seismic energy data analysis of Merapi volcano to test the eruption time prediction using materials failure forecast method (FFM)

    SciTech Connect

    Anggraeni, Novia Antika

    2015-04-24

    The test of eruption time prediction is an effort to prepare volcanic disaster mitigation, especially in the volcano’s inhabited slope area, such as Merapi Volcano. The test can be conducted by observing the increase of volcanic activity, such as seismicity degree, deformation and SO2 gas emission. One of methods that can be used to predict the time of eruption is Materials Failure Forecast Method (FFM). Materials Failure Forecast Method (FFM) is a predictive method to determine the time of volcanic eruption which was introduced by Voight (1988). This method requires an increase in the rate of change, or acceleration of the observed volcanic activity parameters. The parameter used in this study is the seismic energy value of Merapi Volcano from 1990 – 2012. The data was plotted in form of graphs of seismic energy rate inverse versus time with FFM graphical technique approach uses simple linear regression. The data quality control used to increase the time precision employs the data correlation coefficient value of the seismic energy rate inverse versus time. From the results of graph analysis, the precision of prediction time toward the real time of eruption vary between −2.86 up to 5.49 days.

  2. Homocysteine as a predictive biomarker in early diagnosis of renal failure susceptibility and prognostic diagnosis for end stages renal disease.

    PubMed

    Amin, Hatem K; El-Sayed, Mohamed-I Kotb; Leheta, Ola F

    2016-09-01

    Glomerular filtration rate and/or creatinine are not accurate methods for renal failure prediction. This study tested homocysteine (Hcy) as a predictive and prognostic marker for end stage renal disease (ESRD). In total, 176 subjects were recruited and divided into: healthy normal group (108 subjects); mild-to-moderate impaired renal function group (21 patients); severe impaired renal function group (7 patients); and chronic renal failure group (40 patients) who were on regular hemodialysis. Blood samples were collected, and serum was separated for analysis of total Hcy, creatinine, high sensitive C-reactive protein (CRP), serum albumin, and calcium. Data showed that Hcy level was significantly increased from normal-to-mild impairment then significantly decreases from mild impairment until the patient reaches severe impairment while showing significant elevation in the last stage of chronic renal disease. Creatinine level was increased in all stages of kidney impairment in comparison with control. CRP level was showing significant elevation in the last stage. A significant decrease in both albumin and calcium was occurred in all stages of renal impairment. We conclude Hcy in combination with CRP, creatinine, albumin, and calcium can be used as a prognostic marker for ESRD and an early diagnostic marker for the risk of renal failure.

  3. Predictive failure analysis: planning for the worst so that it never happens!

    PubMed

    Hipple, Jack

    2008-01-01

    This article reviews an alternative approach to failure analysis involving a deliberate saboteurial approach rather than a checklist approach to disaster and emergency preparedness. This process is in the form of an algorithm that is easily applied to any planning situation.

  4. An Evolutionary Algorithm for Feature Subset Selection in Hard Disk Drive Failure Prediction

    ERIC Educational Resources Information Center

    Bhasin, Harpreet

    2011-01-01

    Hard disk drives are used in everyday life to store critical data. Although they are reliable, failure of a hard disk drive can be catastrophic, especially in applications like medicine, banking, air traffic control systems, missile guidance systems, computer numerical controlled machines, and more. The use of Self-Monitoring, Analysis and…

  5. Risk Prediction Models of Locoregional Failure After Radical Cystectomy for Urothelial Carcinoma: External Validation in a Cohort of Korean Patients

    SciTech Connect

    Ku, Ja Hyeon; Kim, Myong; Jeong, Chang Wook; Kwak, Cheol; Kim, Hyeon Hoe

    2014-08-01

    Purpose: To evaluate the predictive accuracy and general applicability of the locoregional failure model in a different cohort of patients treated with radical cystectomy. Methods and Materials: A total of 398 patients were included in the analysis. Death and isolated distant metastasis were considered competing events, and patients without any events were censored at the time of last follow-up. The model included the 3 variables pT classification, the number of lymph nodes identified, and margin status, as follows: low risk (≤pT2), intermediate risk (≥pT3 with ≥10 nodes removed and negative margins), and high risk (≥pT3 with <10 nodes removed or positive margins). Results: The bootstrap-corrected concordance index of the model 5 years after radical cystectomy was 66.2%. When the risk stratification was applied to the validation cohort, the 5-year locoregional failure estimates were 8.3%, 21.2%, and 46.3% for the low-risk, intermediate-risk, and high-risk groups, respectively. The risk of locoregional failure differed significantly between the low-risk and intermediate-risk groups (subhazard ratio [SHR], 2.63; 95% confidence interval [CI], 1.35-5.11; P<.001) and between the low-risk and high-risk groups (SHR, 4.28; 95% CI, 2.17-8.45; P<.001). Although decision curves were appropriately affected by the incidence of the competing risk, decisions about the value of the models are not likely to be affected because the model remains of value over a wide range of threshold probabilities. Conclusions: The model is not completely accurate, but it demonstrates a modest level of discrimination, adequate calibration, and meaningful net benefit gain for prediction of locoregional failure after radical cystectomy.

  6. Predicting failure of specimens with either surface cracks or corner cracks at holes

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.

    1976-01-01

    A previously developed fracture criterion was applied to fracture data for surface-cracked specimens subjected to remote tensile loading and for specimens with a corner crack (or cracks) emanating from a circular hole subjected to either remote tensile loading or pin loading in the hole. The failure stresses calculated from this criterion were consistent with experimental failure stresses for both surface and corner cracks for a wide range of crack shapes and crack sizes in specimens of aluminum alloy, titanium alloy, and steel. Empirical equations for the elastic stress-intensity factors for a surface crack and for a corner crack (or cracks) emanating from a circular hole in a finite-thickness and finite-width specimen were also developed.

  7. Robust Multivariate Evaluation and Failure Prediction of Inhomogeneous Solids Based on Inverse Analysis

    DTIC Science & Technology

    2005-12-31

    Measurements of elastic-plastic anisotropic properties of thermally sprayed coatings using nano-indenters and inverse analysis technique...Proceedings of International Thermal Spray Conference. T. Nakamura and Z. Wang (2003), ‘Dynamic Failure Behavior of Elastic-Plastic Graded Materials...Materials, IMRE, Singapore, January 2006. ‘Nonlinear Properties in Plasma Sprayed Coatings and Relation to Process/Materials’, Consortium on Thermal Spray

  8. A literature review and guidance for nurse-led patient extubation in the recovery room/post anaesthetic care unit: endotracheal tubes.

    PubMed

    Dawkins, Sarah

    2011-10-01

    A review of current literature highlighted the lack of national or local guidelines for post anaesthetic care unit (PACU) practitioners/recovery room nurses to extubate their own patients. This article documents the findings of a systematic literature review and gives simple diagrammatic representations from a comprehensive flow chart that has been developed to assist nurses in the extubation process. A knowledge and skills competency validated training package was developed locally with the anaesthetic department to train practitioners to undertake endotracheal extubation safely.

  9. Serum sodium based modification of the MELD does not improve prediction of outcome in acute liver failure

    PubMed Central

    2013-01-01

    Background Acute liver failure (ALF) is a devastating clinical syndrome with a high mortality rate. The MELD score has been implied as a prognostic tool in ALF. Hyponatremia is associated with lethal outcome in ALF. Inclusion of serum sodium (Na) into the MELD score was found to improve its predictive value in cirrhotic patients. Therefore the aim of this study was to determine whether inclusion of serum Na improves the predictive value of MELD in ALF compared to established criteria. Methods In a prospective single center study (11/2006–12/2010), we recruited 108 consecutive ALF patients (64% females / 36% males), who met the criteria defined by the “Acute Liver Failure Study Group Germany”. Upon admission, clinical and laboratory data were collected, King’s College Criteria (KCC), Model of End Stage Liver Disease score (MELD), and serum sodium based modifications like the MELD-Na score and the United Kingdom Model of End Stage Liver Disease score (UKELD) were calculated and area under the receiver operating characteristic curve analyses were performed regarding the prediction of spontaneous recovery (SR) or non-spontaneous recovery (NSR; death or transplantation). Results Serum bilirubin was of no prognostic value in ALF, and Na also failed to predict NSR in ALF. The classical MELD score was superior to sodium-based modifications and KCC. Conclusions We validated the prognostic value of MELD-Na and UKELD in ALF. Classic MELD score calculations performed superior to KCC in the prediction of NSR. Serum Na and Na-based modifications of MELD did not further improve its prognostic value. PMID:23551795

  10. A Novel Risk Stratification to Predict Local-Regional Failures in Urothelial Carcinoma of the Bladder After Radical Cystectomy

    SciTech Connect

    Baumann, Brian C.; Guzzo, Thomas J.; He Jiwei; Keefe, Stephen M.; Tucker, Kai; Bekelman, Justin E.; Hwang, Wei-Ting; Vaughn, David J.; Malkowicz, S. Bruce; Christodouleas, John P.

    2013-01-01

    Purpose: Local-regional failures (LF) following radical cystectomy (RC) plus pelvic lymph node dissection (PLND) with or without chemotherapy for invasive urothelial bladder carcinoma are more common than previously reported. Adjuvant radiation therapy (RT) could reduce LF but currently has no defined role because of previously reported morbidity. Modern techniques with improved normal tissue sparing have rekindled interest in RT. We assessed the risk of LF and determined those factors that predict recurrence to facilitate patient selection for future adjuvant RT trials. Methods and Materials: From 1990-2008, 442 patients with urothelial bladder carcinoma at University of Pennsylvania were prospectively followed after RC plus PLND with or without chemotherapy with routine pelvic computed tomography (CT) or magnetic resonance imaging (MRI). One hundred thirty (29%) patients received chemotherapy. LF was any pelvic failure detected before or within 3 months of distant failure. Competing risk analyses identified factors predicting increased LF risk. Results: On univariate analysis, pathologic stage {>=}pT3, <10 nodes removed, positive margins, positive nodes, hydronephrosis, lymphovascular invasion, and mixed histology significantly predicted LF; node density was marginally predictive, but use of chemotherapy, number of positive nodes, type of surgical diversion, age, gender, race, smoking history, and body mass index were not. On multivariate analysis, only stage {>=}pT3 and <10 nodes removed were significant independent LF predictors with hazard ratios of 3.17 and 2.37, respectively (P<.01). Analysis identified 3 patient subgroups with significantly different LF risks: low-risk ({<=}pT2), intermediate-risk ({>=}pT3 and {>=}10 nodes removed), and high-risk ({>=}pT3 and <10 nodes) with 5-year LF rates of 8%, 23%, and 42%, respectively (P<.01). Conclusions: This series using routine CT and MRI surveillance to detect LF confirms that such failures are relatively common

  11. Prediction of ppm level electrical failure by using physical variation analysis

    NASA Astrophysics Data System (ADS)

    Hou, Hsin-Ming; Kung, Ji-Fu; Hsu, Y.-B.; Yamazaki, Y.; Maruyama, Kotaro; Toyoshima, Yuya; Chen, Chu-en

    2016-03-01

    their spatial correlation distance. For local variations (LV) there is no correlation, whereas for global variations (GV) the correlation distance is very large [7]-[9]. This is the first time to certificate the validation of spatial distribution from the affordable bias contour big data fundamental infrastructures. And then apply statistical techniques to dig out the variation sources. The GV come from systematic issue, which could be compensated by adaptive LT condition or OPC correction. But LV comes from random issue, which being considered as intrinsic problem such as structure, material, tool capability… etc. In this paper studying, we can find out the advanced technology node SRAM contact CD local variation (LV) dominates in total variation, about 70%. It often plays significant in-line real time catching WP-DPMO role of the product yield loss, especially for wafer edge is the worst loss within wafer distribution and causes serious reliability concern. The major root cause of variations comes from the PR material induced burr defect (LV), the second one comes from GV enhanced wafer edge short opportunity, which being attributed to three factors, first one factor is wafer edge CD deliberated enlargement for yield improvement as shown in Fig. 10. Second factor is overlaps/AA shifts due to tool capability dealing with incoming wafer's war page issue and optical periphery layout dependent working pitch issue as shown in Fig. 9 (1)., the last factor comes from wafer edge burr enhanced by wafer edge larger Photo Resistance (PR) spin centrifugal force. After implementing KPIs such as GV related AA/CD indexes as shown in Fig. 9 (1) and 10, respectively, and LV related burr index as shown in Fig. 11., we can construct the parts per million (PPM) level short probability model via multi-variables regression, canonical correlation analysis and logistic transformation. The model provides prediction of PPM level electrical failure by using in-line real time physical

  12. Dynamic failure properties of the porcine medial collateral ligament-bone complex for predicting injury in automotive collisions.

    PubMed

    Peck, Louis; Billiar, Kristen; Ray, Malcolm

    2010-03-09

    The goal of this study was to model the dynamic failure properties of ligaments and their attachment sites to facilitate the development of more realistic dynamic finite element models of the human lower extremities for use in automotive collision simulations. Porcine medial collateral ligaments were chosen as a test model due to their similarities in size and geometry with human ligaments. Each porcine medial collateral ligament-bone complex (n = 12) was held in a custom test fixture placed in a drop tower to apply an axial impulsive impact load, applying strain rates ranging from 0.005 s(-1) to 145 s(-1). The data from the impact tests were analyzed using nonlinear regression to construct model equations for predicting the failure load of ligament-bone complexes subjected to specific strain rates as calculated from finite element knee, thigh, and hip impact simulations. The majority of the ligaments tested failed by tibial avulsion (75%) while the remaining ligaments failed via mid-substance tearing. The failure load ranged from 384 N to 1184 N and was found to increase with the applied strain rate and the product of ligament length and cross-sectional area. The findings of this study indicate the force required to rupture the porcine MCL increases with the applied bone-to-bone strain rate in the range expected from high speed frontal automotive collisions.

  13. Ambulatory heart rate range predicts mode-specific mortality and hospitalisation in chronic heart failure

    PubMed Central

    Cubbon, Richard M; Ruff, Naomi; Groves, David; Eleuteri, Antonio; Denby, Christine; Kearney, Lorraine; Ali, Noman; Walker, Andrew M N; Jamil, Haqeel; Gierula, John; Gale, Chris P; Batin, Phillip D; Nolan, James; Shah, Ajay M; Fox, Keith A A; Sapsford, Robert J; Witte, Klaus K; Kearney, Mark T

    2016-01-01

    Objective We aimed to define the prognostic value of the heart rate range during a 24 h period in patients with chronic heart failure (CHF). Methods Prospective observational cohort study of 791 patients with CHF associated with left ventricular systolic dysfunction. Mode-specific mortality and hospitalisation were linked with ambulatory heart rate range (AHRR; calculated as maximum minus minimum heart rate using 24 h Holter monitor data, including paced and non-sinus complexes) in univariate and multivariate analyses. Findings were then corroborated in a validation cohort of 408 patients with CHF with preserved or reduced left ventricular ejection fraction. Results After a mean 4.1 years of follow-up, increasing AHRR was associated with reduced risk of all-cause, sudden, non-cardiovascular and progressive heart failure death in univariate analyses. After accounting for characteristics that differed between groups above and below median AHRR using multivariate analysis, AHRR remained strongly associated with all-cause mortality (HR 0.991/bpm increase in AHRR (95% CI 0.999 to 0.982); p=0.046). AHRR was not associated with the risk of any non-elective hospitalisation, but was associated with heart-failure-related hospitalisation. AHRR was modestly associated with the SD of normal-to-normal beats (R2=0.2; p<0.001) and with peak exercise-test heart rate (R2=0.33; p<0.001). Analysis of the validation cohort revealed AHRR to be associated with all-cause and mode-specific death as described in the derivation cohort. Conclusions AHRR is a novel and readily available prognosticator in patients with CHF, which may reflect autonomic tone and exercise capacity. PMID:26674986

  14. A model to predict failure of irradiated U–Mo dispersion fuel

    SciTech Connect

    Burkes, Douglas E.; Senor, David J.; Casella, Andrew M.

    2016-12-01

    Numerous global programs are focused on the continued development of existing and new research and test reactor fuels to achieve maximum attainable uranium loadings to support the conversion of a number of the world’s remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Some of these programs are focused on development and qualification of a fuel design that consists of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix as one option for reactor conversion. The current paper extends a failure model originally developed for UO2-stainless steel dispersion fuels and used currently available thermal-mechanical property information for the materials of interest in the current proposed design. A number of fabrication and irradiation parameters were investigated to understand the conditions at which failure of the matrix, classified as pore formation in the matrix, might occur. The results compared well with experimental observations published as part of the Reduced Enrichment for Research and Test Reactors (RERTR)-6 and -7 mini-plate experiments. Fission rate, a function of the 235U enrichment, appeared to be the most influential parameter in premature failure, mainly as a result of increased interaction layer formation and operational temperature, which coincidentally decreased the yield strength of the matrix and caused more rapid fission gas production and recoil into the surrounding matrix material. Addition of silicon to the matrix appeared effective at reducing the rate of interaction layer formation and can extend the performance of a fuel plate under a certain set of irradiation conditions, primarily moderate heat flux and burnup. Increasing the dispersed fuel particle diameter may also be effective, but only when combined with other parameters, e.g., lower enrichment and increased Si concentration. The model may serve as a valuable tool in initial experimental design.

  15. Finite element analysis predicts experimental failure patterns in vertebral bodies loaded via intervertebral discs up to large deformation.

    PubMed

    Clouthier, Allison L; Hosseini, Hadi S; Maquer, Ghislain; Zysset, Philippe K

    2015-06-01

    Vertebral compression fractures are becoming increasingly common. Patient-specific nonlinear finite element (FE) models have shown promise in predicting yield strength and damage pattern but have not been experimentally validated for clinically relevant vertebral fractures, which involve loading through intervertebral discs with varying degrees of degeneration up to large compressive strains. Therefore, stepwise axial compression was applied in vitro on segments and performed in silico on their FE equivalents using a nonlocal damage-plastic model including densification at large compression for bone and a time-independent hyperelastic model for the disc. The ability of the nonlinear FE models to predict the failure pattern in large compression was evaluated for three boundary conditions: healthy and degenerated intervertebral discs and embedded endplates. Bone compaction and fracture patterns were predicted using the local volume change as an indicator and the best correspondence was obtained for the healthy intervertebral discs. These preliminary results show that nonlinear finite element models enable prediction of bone localisation and compaction. To the best of our knowledge, this is the first study to predict the collapse of osteoporotic vertebral bodies up to large compression using realistic loading via the intervertebral discs.

  16. Crisis Management of Accidental Extubation in a Prone-Positioned Patient with Klippel-Feil Syndrome.

    PubMed

    Spond, Matthew; Burns, Tyler; Rosenbaum, Thea; Lienhart, Kristen

    2016-06-15

    We present the case of an accidental extubation in a prone-positioned patient with a challenging airway because of Klippel-Feil syndrome and previous cervical spine fusions. The surgical procedure was well underway when this occurred, which added substantially to the difficulties produced by this event. We herein highlight the corrective steps we took in our case. We also recommend the need for a comprehensive preoperative briefing with all operating room personnel together with an action plan for how to prevent this particular scenario.

  17. Predicting the occurrence of mixed mode failure associated with hydraulic fracturing, part 2 water saturated tests

    SciTech Connect

    Bauer, Stephen J.; Broome, Scott Thomas; Choens, Charles; Barrow, Perry Carl

    2015-09-14

    Seven water-saturated triaxial extension experiments were conducted on four sedimentary rocks. This experimental condition was hypothesized more representative of that existing for downhole hydrofracture and thus it may improve our understanding of the phenomena. In all tests the pore pressure was 10 MPa and confirming pressure was adjusted to achieve tensile and transitional failure mode conditions. Using previous work in this LDRD for comparison, the law of effective stress is demonstrated in extension using this sample geometry. In three of the four lithologies, no apparent chemo-mechanical effect of water is apparent, and in the fourth lithology test results indicate some chemo-mechanical effect of water.

  18. What Predicts Children's Fixed and Growth Intelligence Mind-Sets? Not Their Parents' Views of Intelligence but Their Parents' Views of Failure.

    PubMed

    Haimovitz, Kyla; Dweck, Carol S

    2016-06-01

    Children's intelligence mind-sets (i.e., their beliefs about whether intelligence is fixed or malleable) robustly influence their motivation and learning. Yet, surprisingly, research has not linked parents' intelligence mind-sets to their children's. We tested the hypothesis that a different belief of parents-their failure mind-sets-may be more visible to children and therefore more prominent in shaping their beliefs. In Study 1, we found that parents can view failure as debilitating or enhancing, and that these failure mind-sets predict parenting practices and, in turn, children's intelligence mind-sets. Study 2 probed more deeply into how parents display failure mind-sets. In Study 3a, we found that children can indeed accurately perceive their parents' failure mind-sets but not their parents' intelligence mind-sets. Study 3b showed that children's perceptions of their parents' failure mind-sets also predicted their own intelligence mind-sets. Finally, Study 4 showed a causal effect of parents' failure mind-sets on their responses to their children's hypothetical failure. Overall, parents who see failure as debilitating focus on their children's performance and ability rather than on their children's learning, and their children, in turn, tend to believe that intelligence is fixed rather than malleable.

  19. Embedding measurement within existing computerized data systems: scaling clinical laboratory and medical records heart failure data to predict ICU admission.

    PubMed

    Fisher, William P; Burton, Elizabeth C

    2010-01-01

    This study employs existing data sources to develop a new measure of intensive care unit (ICU) admission risk for heart failure patients. Outcome measures were constructed from laboratory, accounting, and medical record data for 973 adult inpatients with primary or secondary heart failure. Several scoring interpretations of the laboratory indicators were evaluated relative to their measurement and predictive properties. Cases were restricted to tests within first lab draw that included at least 15 indicators. After optimizing the original clinical observations, a satisfactory heart failure severity scale was calibrated on a 0-1000 continuum. Patients with unadjusted CHF severity measures of 550 or less were 2.7 times more likely to be admitted to the ICU than those with higher measures. Patients with low HF severity measures (550 or less) adjusted for demographic and diagnostic risk factors are about six times more likely to be admitted to the ICU than those with higher adjusted measures. A nomogram facilitates routine clinical application. Existing computerized data systems could be programmed to automatically structure clinical laboratory reports using the results of studies like this one to reduce data volume with no loss of information, make laboratory results more meaningful to clinical end users, improve the quality of care, reduce errors and unneeded tests, prevent unnecessary ICU admissions, lower costs, and improve patient satisfaction. Existing data typically examined piecemeal form a coherent scale measuring heart failure severity sensitive to increased likelihood of ICU admission. Marked improvements in ROC curves were found for the aggregate measures relative to individual clinical indicators.

  20. Circulating Adiponectin Levels Following Treatment Can Predict Late Clinical Outcomes in Chronic Heart Failure

    PubMed Central

    Yu, Ho-Ping; Jen, Hsu-Lung; Yin, Wei-Hsian; Wei, Jeng

    2017-01-01

    Background Circulating adiponectin concentration increases in patients with chronic heart failure (HF). We sought to explore the prognostic value of temporal changes in adiponectin concentration following treatment for chronic HF. Methods Serum adiponectin levels were measured at baseline and after a 3-month anti-failure treatment in 124 patients with symptomatic chronic systolic HF. Major adverse cardiac events (MACE) including death, heart transplantation, or hospitalization with worsening HF during a median follow-up period of 752 days were determined. Results Univariate and multivariate analysis showed that high levels of adiponectin after a 3-month treatment were associated with a 3.8-fold increased risk of MACE (p = 0.03), independent of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. Moreover, the combining of circulating levels of adiponectin with NT-proBNP provided independent and additional prognostic value in identifying high risk patients with MACE during follow-up. Conclusions Changes in adiponectin and NT-proBNP over time provide prognostic information. When adiponectin is used in conjunction with NT-proBNP in chronic HF, the prognostic value may be better than if each biomarker is used separately. PMID:28344417

  1. Predicting outflow induced by moraine failure in glacial lakes: the Lake Palcacocha case from an uncertainty perspective

    NASA Astrophysics Data System (ADS)

    Rivas, D. S.; Somos-Valenzuela, M. A.; Hodges, B. R.; McKinney, D. C.

    2015-06-01

    Moraine dam collapse is one of the causes of glacial lake outburst floods. Available models seek to predict both moraine breach formation and lake outflow. The models depend on hydraulic, erosion, and geotechnical parameters that are mostly unknown or uncertain. This paper estimates the outflow hydrograph caused by a potential erosive collapse of the moraine dam of Lake Palcacocha in Peru and quantifies the uncertainty of the results. The overall aim is to provide a simple yet hydraulically robust approach for calculating the expected outflow hydrographs that is useful for risk assessment studies. To estimate the peak outflow and failure time of the hydrograph, we assessed several available empirical equations based on lake and moraine geometries; each equation has defined confidence intervals for peak flow predictions. Complete outflow hydrographs for each peak flow condition were modeled using a hydraulic simulation model calibrated to match the peak flows estimated with the empirical equations. Failure time and peak flow differences between the simulations, and the corresponding empirical equations were used as error parameters. Along with an expected hydrograph, lower and upper bound hydrographs were calculated for Lake Palcacocha, representing the confidence interval of the results. The approach has several advantages: first, it is simple and robust. Second, it evaluates the capability of empirical equations to reproduce the conditions of the lake and moraine dam. Third, this approach accounts for uncertainty in the hydrographs estimations, which makes it appropriate for risk management studies.

  2. Predicting outflow induced by moraine failure in glacial lakes: the Lake Palcacocha case from an uncertainty perspective

    NASA Astrophysics Data System (ADS)

    Rivas, D. S.; Somos-Valenzuela, M. A.; McKinney, D. C.; Hodges, B. R.

    2014-09-01

    Moraine dam collapse is one of the causes of Glacier Lake Outburst Floods. Available models seek to predict both moraine breach formation and lake outflow. The models depend on hydraulic, erosion, and geotechnical parameters that are mostly unknown or uncertain. This paper estimates the outflow hydrograph caused by a potential collapse of the moraine dam of Lake Palcacocha in Peru and quantifies the uncertainty of the results. The overall aim is to provide a simple and robust method of calculation of the expected outflow hydrographs that is useful for risk assessment studies. To estimate the peak outflow and failure time of the hydrograph, we assessed several available empirical equations based on lake and moraine geometries; each equation has defined confidence intervals for peak flow predictions. Complete outflow hydrographs for each peak flow condition were modeled using a~hydraulic simulation model calibrated to meet the peak flows estimated with the empirical equations. Failure time and peak flow differences between the simulations and the corresponding empirical equations were used as error parameters. Along with an expected hydrograph, lower and upper bound hydrographs were calculated for Lake Palcacocha, representing the confidence interval of the results. The method has several advantages: first, it is simple and robust. Second, it evaluates the capability of empirical equations to reproduce the conditions of the lake and moraine dam. Third, this method accounts for uncertainty in the hydrographs estimations, which makes it appropriate for risk management studies.

  3. Does the Theory of Planned Behavior Predict Dietary Sodium Intake in Patients With Heart Failure?

    PubMed

    Wu, Jia-Rong; Lennie, Terry A; Dunbar, Sandra B; Pressler, Susan J; Moser, Debra K

    2016-10-18

    Sodium intake in heart failure (HF) is a crucial but poorly understood phenomenon. Theoretical models promote understanding and provide a context for rational appraisal of complex situations. The purpose of this study was to determine which factors were associated with sodium intake in HF patients using theory of planned behavior (TPB). In this study, patients' (N = 244) attitudes, subjective norms, and perceived behavioral control (tenets of the TPB) were assessed using the Dietary Sodium Restriction Questionnaire. Sodium intake was estimated objectively by 24-hr urinary sodium excretion (UNa). The average UNa was 3,811 mg. Subjective norms, gender, and New York Heart Association functional class were associated with sodium intake (p < .001). Thus, it is important for health care providers to clearly express their approval of following low-sodium diet to their HF patients, and include significant others in interventions to help patients develop/maintain a positive subjective norm to decrease sodium intake and reduce HF exacerbations.

  4. The Homeostatic Chemokine CCL21 Predicts Mortality and May Play a Pathogenic Role in Heart Failure

    PubMed Central

    Yndestad, Arne; Finsen, Alexandra Vanessa; Ueland, Thor; Husberg, Cathrine; Dahl, Christen P.; Øie, Erik; Vinge, Leif Erik; Sjaastad, Ivar; Sandanger, Øystein; Ranheim, Trine; Dickstein, Kenneth; Kjekshus, John; Damås, Jan Kristian; Fiane, Arnt E.; Hilfiker-Kleiner, Denise; Lipp, Martin; Gullestad, Lars; Christensen, Geir; Aukrust, Pål

    2012-01-01

    Background CCL19 and CCL21, acting through CCR7, are termed homeostatic chemokines. Based on their role in concerting immunological responses and their proposed involvement in tissue remodeling, we hypothesized that these chemokines could play a pathogenic role in heart failure (HF). Methodology/Principal Findings Our main findings were: (i) Serum levels of CCL19 and particularly CCL21 were markedly raised in patients with chronic HF (n = 150) as compared with healthy controls (n = 20). A CCL21 level above median was independently associated with all-cause mortality. (ii) In patients with HF following acute myocardial infarction (MI; n = 232), high versus low CCL21 levels 1 month post-MI were associated with cardiovascular mortality, even after adjustment for established risk factors. (iii). Explanted failing human LV tissue (n = 29) had markedly increased expression of CCL21 as compared with non-failing myocardium (n = 5). (iv) Our studies in CCR7−/− mice showed improved survival and attenuated increase in markers of myocardial dysfunction and wall stress in post-MI HF after 1 week, accompanied by increased myocardial expression of markers of regulatory T cells. (v) Six weeks post-MI, there was an increase in markers of myocardial dysfunction and wall stress in CCR7 deficient mice. Conclusions/Significance High serum levels of CCL21 are independently associated with mortality in chronic and acute post-MI HF. Our findings in CCR7 deficient mice may suggest that CCL21 is not only a marker, but also a mediator of myocardial failure. However, while short term inhibition of CCR7 may be beneficial following MI, a total lack of CCR7 during long-term follow-up could be harmful. PMID:22427939

  5. Tailor-made heart simulation predicts the effect of cardiac resynchronization therapy in a canine model of heart failure.

    PubMed

    Panthee, Nirmal; Okada, Jun-ichi; Washio, Takumi; Mochizuki, Youhei; Suzuki, Ryohei; Koyama, Hidekazu; Ono, Minoru; Hisada, Toshiaki; Sugiura, Seiryo

    2016-07-01

    Despite extensive studies on clinical indices for the selection of patient candidates for cardiac resynchronization therapy (CRT), approximately 30% of selected patients do not respond to this therapy. Herein, we examined whether CRT simulations based on individualized realistic three-dimensional heart models can predict the therapeutic effect of CRT in a canine model of heart failure with left bundle branch block. In four canine models of failing heart with dyssynchrony, individualized three-dimensional heart models reproducing the electromechanical activity of each animal were created based on the computer tomographic images. CRT simulations were performed for 25 patterns of three ventricular pacing lead positions. Lead positions producing the best and the worst therapeutic effects were selected in each model. The validity of predictions was tested in acute experiments in which hearts were paced from the sites identified by simulations. We found significant correlations between the experimentally observed improvement in ejection fraction (EF) and the predicted improvements in ejection fraction (P<0.01) or the maximum value of the derivative of left ventricular pressure (P<0.01). The optimal lead positions produced better outcomes compared with the worst positioning in all dogs studied, although there were significant variations in responses. Variations in ventricular wall thickness among the dogs may have contributed to these responses. Thus CRT simulations using the individualized three-dimensional heart models can predict acute hemodynamic improvement, and help determine the optimal positions of the pacing lead.

  6. Risk factors for post-extubation stridor in children: the role of orotracheal cannula

    PubMed Central

    Nascimento, Milena Siciliano; Prado, Cristiane; Troster, Eduardo Juan; Valério, Naiana; Alith, Marcela Batan; de Almeida, João Fernando Lourenço

    2015-01-01

    Objective To determine the risk factors associated with stridor, with special attention to the role of the cuffed orotracheal cannula. Methods Prospective analysis of all the intubated patients submitted to mechanical ventilator support from January 2008 to April 2011. The relevant factors for stridor collected were age, weight, size and type of airway tube, diagnosis, and duration of mechanical ventilation. The effects of variables on stridor were evaluated using uni- and multivariate logistic regression models. Results A total of 136 patients were included. Mean age was 1.4 year (3 days to 17 years). The mean duration of mechanical ventilation was 73.5 hours. Fifty-six patients (41.2%) presented with stridor after extubation. The total reintubation rate was 19.6% and 12.5 in patients with and without stridor, respectively. The duration of mechanical ventilation (>72 hours) was associated with a greater risk for stridor (odds ratio of 8.60; 95% confidence interval of 2.98-24.82; p<0.001). The presence of the cuffed orotracheal cannula was not associated with stridor (odds ratio of 98; 95% confidence interval of 0.46-2.06; p=0.953). Conclusion The main risk factor for stridor after extubation in our population was duration of mechanical ventilation. The presence of the cuffed orotracheal cannula was not associated with increased risk for stridor, reinforcing the use of the cuffed orotracheal cannula in children with respiratory distress. PMID:26061076

  7. Diffusional transport and predicting oxidative failure during cyclic oxidation of beta-NiAl alloys

    NASA Technical Reports Server (NTRS)

    Nesbitt, J. A.; Vinarcik, E. J.; Barrett, C. A.; Doychak, J.

    1992-01-01

    Nickel aluminides (NiAl) containing 40-50 at. percent Al and up to 0.1 at. percent Zr have been studied following cyclic oxidation at 1200, 1300, 1350 and 1400 C. The selective oxidation of aluminum resulted in the formation of protective Al2O3 scales on each alloy composition at each temperature. However, repeated cycling eventually resulted in the gradual formation of less protective NiAl2O4. The appearance of the NiAl2O4, signaling the end of the protective scale-forming capability of the alloy, was related to the presence of gamma-prime-(Ni3Al) which formed as a result of the loss of aluminum from the sample. A simple methodology is presented to predict the protective life of beta-NiAl alloys. This method predicts the oxidative lifetime due to aluminum depletion when the aluminum concentration decreases to a critical concentration. The time interval preceding NiAl2O4 formation (i.e., the lifetime based on protective Al2O3 formation) and predicted lifetimes are compared and discussed. Use of the method to predict the maximum use temperature for NiAl-Zr alloys is also discussed.

  8. Predictive value of daily living score in acute respiratory failure of COPD patients requiring invasive mechanical ventilation pilot study

    PubMed Central

    2012-01-01

    Background Mechanical ventilation (MV) is imperative in many forms of acute respiratory failure (ARF) in COPD patients. Previous studies have shown the difficulty to identify parameters predicting the outcome of COPD patients treated by invasive MV. Our hypothesis was that a non specialized score as the activities daily living (ADL) score may help to predict the outcome of these patients. Methods We studied the outcome of 25 COPD patients admitted to the intensive care unit for ARF requiring invasive MV. The patients were divided into those weaning success (group A n = 17, 68%) or failure (group B n = 8, 32%). We investigated the correlation between the ADL score and the outcome and mortality. Results The ADL score was higher in group A (5.1 ±1.1 vs 3.7 ± 0.7 in group B, p < 0.01). Weaning was achieved in 76.5% of the cases with an ADL score ≥ 4 and in 23.5% of the cases with an ADL score < 4 (p < 0.05). Pulmonary function test, arterial blood gases collected during period of clinical stability and at admission and nutritional status were similar in both groups. The mortality, at six months, was 36%. The ADL score was a significant predictor of 6-month mortality (80 with an ADL score <4, 20 with an ADL score ≥4, p < 0.01). Conclusion Our pilot study demonstrates that the ADL score is predictive of weaning success and mortality at 6 months, suggesting that the assessment of daily activities should be an important component of ARF management in COPD patients. PMID:23078114

  9. Combined In-Plane and Through-the-Thickness Analysis for Failure Prediction of Bolted Composite Joints

    NASA Technical Reports Server (NTRS)

    Kradinov, V.; Madenci, E.; Ambur, D. R.

    2004-01-01

    Although two-dimensional methods provide accurate predictions of contact stresses and bolt load distribution in bolted composite joints with multiple bolts, they fail to capture the effect of thickness on the strength prediction. Typically, the plies close to the interface of laminates are expected to be the most highly loaded, due to bolt deformation, and they are usually the first to fail. This study presents an analysis method to account for the variation of stresses in the thickness direction by augmenting a two-dimensional analysis with a one-dimensional through the thickness analysis. The two-dimensional in-plane solution method based on the combined complex potential and variational formulation satisfies the equilibrium equations exactly, and satisfies the boundary conditions and constraints by minimizing the total potential. Under general loading conditions, this method addresses multiple bolt configurations without requiring symmetry conditions while accounting for the contact phenomenon and the interaction among the bolts explicitly. The through-the-thickness analysis is based on the model utilizing a beam on an elastic foundation. The bolt, represented as a short beam while accounting for bending and shear deformations, rests on springs, where the spring coefficients represent the resistance of the composite laminate to bolt deformation. The combined in-plane and through-the-thickness analysis produces the bolt/hole displacement in the thickness direction, as well as the stress state in each ply. The initial ply failure predicted by applying the average stress criterion is followed by a simple progressive failure. Application of the model is demonstrated by considering single- and double-lap joints of metal plates bolted to composite laminates.

  10. DNA Repair Biomarker Profiling of Head & Neck Cancer: Ku80 Expression Predicts Locoregional Failure and Death Following Radiotherapy

    PubMed Central

    Moeller, Benjamin J.; Yordy, John S.; Williams, Michelle D.; Giri, Uma; Raju, Uma; Molkentine, David P.; Byers, Lauren A.; Heymach, John V.; Story, Michael D.; Lee, J. Jack; Sturgis, Erich M.; Weber, Randal S.; Garden, Adam S.; Ang, K. Kian; Schwartz, David L.

    2011-01-01

    Purpose Radiotherapy plays an integral role in the treatment of head and neck squamous cell carcinoma (HNSCC). Although proteins involved in DNA repair may predict HNSCC response to radiotherapy, none has been validated in this context. We examined whether differential expression of double-strand DNA break (DSB) repair proteins in HNSCC, the chief mediators of DNA repair following irradiation, predict for treatment outcomes. Experimental Design Archival HNSCC tumor specimens (n = 89) were assembled onto a tissue microarray and stained with antibodies raised against 38 biomarkers. The biomarker set was enriched for proteins involved in DSB repair, in addition to established mechanistic markers of radioresistance. Staining was correlated with treatment response and survival alongside established clinical and pathologic covariates. Results were validated in an independent intramural cohort (n = 34). Results Ku80, a key mediator of DSB repair, correlated most closely with clinical outcomes. Ku80 was overexpressed in half of all tumors, and its expression was independent of all other covariates examined. Ku80 overexpression was an independent predictor for both locoregional failure and mortality following radiotherapy (P < 0.01). The predictive power of Ku80 overexpression was confined largely to HPV-negative HNSCC, where it conferred a 9-fold greater risk of death at 2 years. Conclusions Ku80 overexpression is a common feature of HNSCC, and is a candidate DNA repair-related biomarker for radiation treatment failure and death, particularly in patients with high-risk HPV-negative disease. It is a promising, mechanistically rational biomarker to select individual HPV-negative HNSCC patients for strategies to intensify treatment. PMID:21349997

  11. Developing EHR-driven heart failure risk prediction models using CPXR(Log) with the probabilistic loss function.

    PubMed

    Taslimitehrani, Vahid; Dong, Guozhu; Pereira, Naveen L; Panahiazar, Maryam; Pathak, Jyotishman

    2016-04-01

    Computerized survival prediction in healthcare identifying the risk of disease mortality, helps healthcare providers to effectively manage their patients by providing appropriate treatment options. In this study, we propose to apply a classification algorithm, Contrast Pattern Aided Logistic Regression (CPXR(Log)) with the probabilistic loss function, to develop and validate prognostic risk models to predict 1, 2, and 5year survival in heart failure (HF) using data from electronic health records (EHRs) at Mayo Clinic. The CPXR(Log) constructs a pattern aided logistic regression model defined by several patterns and corresponding local logistic regression models. One of the models generated by CPXR(Log) achieved an AUC and accuracy of 0.94 and 0.91, respectively, and significantly outperformed prognostic models reported in prior studies. Data extracted from EHRs allowed incorporation of patient co-morbidities into our models which helped improve the performance of the CPXR(Log) models (15.9% AUC improvement), although did not improve the accuracy of the models built by other classifiers. We also propose a probabilistic loss function to determine the large error and small error instances. The new loss function used in the algorithm outperforms other functions used in the previous studies by 1% improvement in the AUC. This study revealed that using EHR data to build prediction models can be very challenging using existing classification methods due to the high dimensionality and complexity of EHR data. The risk models developed by CPXR(Log) also reveal that HF is a highly heterogeneous disease, i.e., different subgroups of HF patients require different types of considerations with their diagnosis and treatment. Our risk models provided two valuable insights for application of predictive modeling techniques in biomedicine: Logistic risk models often make systematic prediction errors, and it is prudent to use subgroup based prediction models such as those given by CPXR

  12. A study of the usefulness of the HESI Exit Exam in predicting NCLEX-RN failure.

    PubMed

    Spurlock, Darrell R; Hunt, Linda A

    2008-04-01

    Schools of nursing across the country are implementing progression policies that prohibit students from graduating or from taking the nursing licensure examination, sometimes based solely on a single predictive test score. In addition, little empirical evidence exists that supports progression policies as effective in increasing a school's NCLEX-RN pass rates. This article reports on a study conducted when one school did not achieve the results they expected after implementing a progression policy. With use of logistic regression, diagnostic indexes, and other methods, reasons for the disparity between expected and observed NCLEX-RN pass rates were examined. Results revealed that the Health Education Systems, Inc. (HESI) Exit Exam was not able to accurately predict NCLEX-RN outcomes for graduates and, further, that progression policies that allow retest after retest so as to achieve a minimum score on the HESI Exit Exam are not supported empirically. Conclusions and suggestions for schools using or considering progression policies are provided.

  13. The predictive value of plasma biomarkers in discharged heart failure patients: the role of plasma BNP.

    PubMed

    Beltrami, Matteo; Palazzuoli, Alberto; Ruocco, Gaetano; Aspromonte, Nadia

    2016-04-01

    To date, heart failure (HF) prognosis is still difficult: symptoms and signs are often non-specific, and poor sensitive indicators for HF severity. Brain natriuretic peptide (BNP) is now included in the current guidelines for HF diagnosis, management and risk assessment because of its high specificity and sensibility. BNP became a first-line exam in HF patients' evaluation at hospital admission together with clinical and chest X-ray. In discharged patients, the prognostic role of BNP is associated with decongestion and its significant reduction compared to admission level appears one of the best outcome predictors. In fact BNP measurement could identify patients with increased risk of adverse events and left ventricular remodeling. Although a single BNP value assay and the absolute value during hospitalization is related to the prognosis, especially at discharge. On the other hand, hormone levels could be influenced by several factors (i.e., renal dysfunction, anemia, age, liver insufficiency, Body Mass Index) independently from systemic and pulmonary congestion. Therefore, a new approach which considers a multimodality strategy including BNP assay among the traditional clinical examination and imaging studies should be routinely encouraged to better define cardiac dysfunction's etiology and severity, as well as to recognize patients at risk of adverse outcome.

  14. Predicting Honeybee Colony Failure: Using the BEEHAVE Model to Simulate Colony Responses to Pesticides.

    PubMed

    Rumkee, Jack C O; Becher, Matthias A; Thorbek, Pernille; Kennedy, Peter J; Osborne, Juliet L

    2015-11-03

    To simulate effects of pesticides on different honeybee (Apis mellifera L.) life stages, we used the BEEHAVE model to explore how increased mortalities of larvae, in-hive workers, and foragers, as well as reduced egg-laying rate, could impact colony dynamics over multiple years. Stresses were applied for 30 days, both as multiples of the modeled control mortality and as set percentage daily mortalities to assess the sensitivity of the modeled colony both to small fluctuations in mortality and periods of low to very high daily mortality. These stresses simulate stylized exposure of the different life stages to nectar and pollen contaminated with pesticide for 30 days. Increasing adult bee mortality had a much greater impact on colony survival than mortality of bee larvae or reduction in egg laying rate. Importantly, the seasonal timing of the imposed mortality affected the magnitude of the impact at colony level. In line with the LD50, we propose a new index of "lethal imposed stress": the LIS50 which indicates the level of stress on individuals that results in 50% colony mortality. This (or any LISx) is a comparative index for exploring the effects of different stressors at colony level in model simulations. While colony failure is not an acceptable protection goal, this index could be used to inform the setting of future regulatory protection goals.

  15. Predicting Honeybee Colony Failure: Using the BEEHAVE Model to Simulate Colony Responses to Pesticides

    PubMed Central

    2015-01-01

    To simulate effects of pesticides on different honeybee (Apis mellifera L.) life stages, we used the BEEHAVE model to explore how increased mortalities of larvae, in-hive workers, and foragers, as well as reduced egg-laying rate, could impact colony dynamics over multiple years. Stresses were applied for 30 days, both as multiples of the modeled control mortality and as set percentage daily mortalities to assess the sensitivity of the modeled colony both to small fluctuations in mortality and periods of low to very high daily mortality. These stresses simulate stylized exposure of the different life stages to nectar and pollen contaminated with pesticide for 30 days. Increasing adult bee mortality had a much greater impact on colony survival than mortality of bee larvae or reduction in egg laying rate. Importantly, the seasonal timing of the imposed mortality affected the magnitude of the impact at colony level. In line with the LD50, we propose a new index of “lethal imposed stress”: the LIS50 which indicates the level of stress on individuals that results in 50% colony mortality. This (or any LISx) is a comparative index for exploring the effects of different stressors at colony level in model simulations. While colony failure is not an acceptable protection goal, this index could be used to inform the setting of future regulatory protection goals. PMID:26444386

  16. The deterministic prediction of failure of low pressure steam turbine disks

    SciTech Connect

    Liu, Chun; Macdonald, D.D.

    1993-05-01

    Localized corrosion phenomena, including pitting corrosion, stress corrosion cracking, and corrosion fatigue, are the principal causes of corrosion-induced damage in electric power generating facilities and typically result in more than 50% of the unscheduled outages. Prediction of damage, so that repairs and inspections can be made during scheduled outages, could have an enormous impact on the economics of electric power generation. To date, prediction of corrosion damage has been made on the basis of empirical/statistical methods that have proven to be insufficiently robust and accurate to form the basis for the desired inspection/repair protocol. In this paper, we describe a deterministic method for predicting localized corrosion damage. We have used the method to illustrate how pitting corrosion initiates stress corrosion cracking (SCC) for low pressure steam turbine disks downstream of the Wilson line, where a thin condensed liquid layer exists on the steel disk surfaces. Our calculations show that the SCC initiation and propagation are sensitive to the oxygen content of the steam, the environment in the thin liquid condensed layer, and the stresses that the disk experiences in service.

  17. Telomere Length Assessment for Prediction of Organ Transplantation Outcome. Future or Failure: A Review of the Literature

    PubMed Central

    Kłoda, Karolina; Domański, Leszek; Mierzecki, Artur

    2017-01-01

    Telomeres are located at each end of eukaryotic chromosomes. Their functional role is genomic stability maintenance. The protective role of telomeres depends on various factors, including number of nucleotides repeats, telomere-binding proteins, and telomerase activity. Organ transplantation is the preferred replacement therapy in the case of chronic kidney disease and the only possibility of sustaining recipients’ life in the case of advanced liver failure. While the prevalence of acute rejection is constantly decreasing, prevention of transplanted organ long-term function loss is still challenging. It has been demonstrated that post-transplant stressors accelerate aging of the allografts manifested through telomere shortening. The aim of this paper was to evaluate the importance of telomere length assessment for prediction of organ transplantation outcome. Literature review included the 10 most important studies regarding linkage between allograft function and telomere erosion, including 2 of our own reports. Telomere length assessment is useful to predict organ transplantation outcome. The importance of telomere length as a prediction marker depends on the analyzed material. To obtain reliable results, both graft cells (donor material) and lymphocytes (recipient material) should be examined. In the case of kidney transplantation, assessment of telomere length in the early post-transplant period allows prediction of the long-term function of the transplanted organ. To increase the accuracy of transplantation outcome prediction, telomere length assessment should be combined with evaluation of other aging biomarkers, like CDKN2A (p16). Large-scale clinical studies regarding telomere length measurement, including genome wide association analysis introducing relevant genetic factors, are needed for the future. PMID:28076340

  18. Development of a Patient-Specific Finite Element Model for Predicting Implant Failure in Pelvic Ring Fracture Fixation

    PubMed Central

    Höch, Andreas; Peldschus, Steffen

    2017-01-01

    Introduction. The main purpose of this study is to develop an efficient technique for generating FE models of pelvic ring fractures that is capable of predicting possible failure regions of osteosynthesis with acceptable accuracy. Methods. Patient-specific FE models of two patients with osteoporotic pelvic fractures were generated. A validated FE model of an uninjured pelvis from our previous study was used as a master model. Then, fracture morphologies and implant positions defined by a trauma surgeon in the preoperative CT were manually introduced as 3D splines to the master model. Four loading cases were used as boundary conditions. Regions of high stresses in the models were compared with actual locations of implant breakages and loosening identified from follow-up X-rays. Results. Model predictions and the actual clinical outcomes matched well. For Patient A, zones of increased tension and maximum stress coincided well with the actual locations of implant loosening. For Patient B, the model predicted accurately the loosening of the implant in the anterior region. Conclusion. Since a significant reduction in time and labour was achieved in our mesh generation technique, it can be considered as a viable option to be implemented as a part of the clinical routine to aid presurgical planning and postsurgical management of pelvic ring fracture patients. PMID:28255332

  19. Development of a Patient-Specific Finite Element Model for Predicting Implant Failure in Pelvic Ring Fracture Fixation.

    PubMed

    Shim, Vickie; Höch, Andreas; Grunert, Ronny; Peldschus, Steffen; Böhme, Jörg

    2017-01-01

    Introduction. The main purpose of this study is to develop an efficient technique for generating FE models of pelvic ring fractures that is capable of predicting possible failure regions of osteosynthesis with acceptable accuracy. Methods. Patient-specific FE models of two patients with osteoporotic pelvic fractures were generated. A validated FE model of an uninjured pelvis from our previous study was used as a master model. Then, fracture morphologies and implant positions defined by a trauma surgeon in the preoperative CT were manually introduced as 3D splines to the master model. Four loading cases were used as boundary conditions. Regions of high stresses in the models were compared with actual locations of implant breakages and loosening identified from follow-up X-rays. Results. Model predictions and the actual clinical outcomes matched well. For Patient A, zones of increased tension and maximum stress coincided well with the actual locations of implant loosening. For Patient B, the model predicted accurately the loosening of the implant in the anterior region. Conclusion. Since a significant reduction in time and labour was achieved in our mesh generation technique, it can be considered as a viable option to be implemented as a part of the clinical routine to aid presurgical planning and postsurgical management of pelvic ring fracture patients.

  20. Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys

    SciTech Connect

    Farmer, J C

    2003-04-15

    DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption in crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with

  1. Fully Coupled Micro/Macro Deformation, Damage, and Failure Prediction for SiC/Ti-15-3 Laminates

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.; Lerch, Brad A.

    2001-01-01

    The deformation, failure, and low cycle fatigue life of SCS-6/Ti-15-3 composites are predicted using a coupled deformation and damage approach in the context of the analytical generalized method of cells (GMC) micromechanics model. The local effects of inelastic deformation, fiber breakage, fiber-matrix interfacial debonding, and fatigue damage are included as sub-models that operate on the micro scale for the individual composite phases. For the laminate analysis, lamination theory is employed as the global or structural scale model, while GMC is embedded to operate on the meso scale to simulate the behavior of the composite material within each laminate layer. While the analysis approach is quite complex and multifaceted, it is shown, through comparison with experimental data, to be quite accurate and realistic while remaining extremely efficient.

  2. Modeling of void coalescence initiation and its impact on the prediction of material failure

    NASA Astrophysics Data System (ADS)

    Msolli, Sabeur; Bettaieb, Mohamed Ben; Abed-Meraim, Farid

    2016-10-01

    In the present paper, Thomason's criterion is coupled with the well-known Gurson-Tvergaard-Needleman (GTN) damage model and used for the determination of the critical void volume fraction fc, which marks the initiation of the coalescence stage. The onset of void coalescence predicted by Thomason's criterion is compared to that obtained by using a predefined fc, which is usually fitted on the basis of experimental results, as originally proposed in the GTN model. Comparisons are made in terms of both single finite element simulations and numerical results of deep drawing of a cup.

  3. Worst-Case Prediction of Single-Particle-Induced Permanent Failures in Microelectronics.

    DTIC Science & Technology

    1981-07-01

    ATTN DAMA-RAX, SYS REVIEW & PIIKHAVN NATIONAL LAIROPATORY WASHINGTON, 15’ 20101 ANALYSIS UFC ASS’AIATED, UNIVERSITIES, IN ’ ATTN DAMA- CSS -D, R&D TEAM...CHART NA A l l I i I 666of ,IANIAktl 64 A, V൴ L UNCLASSIFIED 14 ) REPORT DOCUMENTATION PAGE BFRE COSTRUTINSOR Worst-Case Prediction of Single...Washington, DC 20305 IS*. oEcL ASSI F C ATIONOWNGRAING 16. DISTRIBUTION STATEMENT (of this Report ) Approved for public release, distribution unlimited. 17

  4. Post-Exercise Heart Rate Recovery Independently Predicts Clinical Outcome in Patients with Acute Decompensated Heart Failure

    PubMed Central

    Youn, Jong-Chan; Lee, Hye Sun; Choi, Suk-Won; Han, Seong-Woo; Ryu, Kyu-Hyung; Shin, Eui-Cheol; Kang, Seok-Min

    2016-01-01

    Background Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcome in patients with chronic heart failure. However, its relationship with the pro-inflammatory response and prognostic value in consecutive patients with acute decompensated heart failure (ADHF) has not been investigated. Methods We measured HRR and pro-inflammatory markers in 107 prospectively and consecutively enrolled, recovered ADHF patients (71 male, 59 ± 15 years, mean ejection fraction 28.9 ± 14.2%) during the pre-discharge period. The primary endpoint included cardiovascular (CV) events defined as CV mortality, cardiac transplantation, or rehospitalization due to HF aggravation. Results The CV events occurred in 30 (28.0%) patients (5 cardiovascular deaths and 7 cardiac transplantations) during the follow-up period (median 214 days, 11–812 days). When the patients with ADHF were grouped by HRR according to the Contal and O’Quigley’s method, low HRR was shown to be associated with significantly higher levels of serum monokine-induced by gamma interferon (MIG) and poor clinical outcome. Multivariate Cox regression analysis revealed that low HRR was an independent predictor of CV events in both enter method and stepwise method. The addition of HRR to a model significantly increased predictability for CV events across the entire follow-up period. Conclusion Impaired post-exercise HRR is associated with a pro-inflammatory response and independently predicts clinical outcome in patients with ADHF. These findings may explain the relationship between autonomic dysfunction and clinical outcome in terms of the inflammatory response in these patients. PMID:27135610

  5. A physically-based method for predicting peak discharge of floods caused by failure of natural and constructed earthen dams

    USGS Publications Warehouse

    Walder, J.S.; O'Connor, J. E.; Costa, J.E.; ,

    1997-01-01

    We analyse a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V.D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether < ??? 1 or < ??? 1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.We analyze a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V/D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a

  6. Right ventricular failure predicted from right bundle branch block: cardiac magnetic resonance imaging validation

    PubMed Central

    Arora, Sameer; Ahmad, Ali; Sood, Mike; El Sergany, Amaar; Sacchi, Terrence; Saul, Barry; Gaglani, Rahul; Heitner, John

    2016-01-01

    Background Right ventricular (RV) failure has proven to be independently associated with adverse outcomes. Electrocardiographic parameters assessing RV function are largely unknown, making echocardiography the first line for RV function assessment. It is however, limited by geometrical assumptions and is inferior to cardiac magnetic resonance imaging (CMRI) which is widely regarded as the most accurate tool for assessing RV function. Methods We seek to determine the correlation of ECG parameters of right bundle branch block (RBBB) with RV ejection fraction (EF) and RV dimensions using the CMRI. QRS duration, R amplitude and R’ duration were obtained from precordial lead V1; S duration and amplitude were obtained from lead I and AVL. RV systolic dysfunction was defined as RV EF <40%. RV systolic dysfunction group (mean EF of 24±10%) were compared with normal RV systolic function group which acted as control (mean EF of 48±8%). CMRI and ECG parameters were compared between the two groups. Rank correlations and scatter diagrams between individual CMRI parameters and ECG parameters were done using medcalc for windows, version 12.5. Sensitivity, specificity and area under the curve (AUC) were calculated. Results RV systolic dysfunction group was found to have larger RV end systolic volumes (90±42 vs. 59±40 mL, P=0.02). ECG evaluation of RV dysfunction group revealed longer R’ duration (103±22 vs. 84±18 msec, P=0.005) as compared to the control group. The specificity of R’ duration >100 msec to detect RV systolic dysfunction was found to be 93%. R’ duration was found to have an inverse correlation with RV EF (r=−0.49, P=0.007). Conclusions Larger RV end systolic volumes seen with RV dysfunction can affect the latter part of right bundle branch leading to prolonged R’ duration. We here found prolonged R’ duration in lead V1 to have a highly specific inverse correlation to RV systolic function. ECG can be used as an inexpensive tool for RV function

  7. Time Granularity Transformation of Time Series Data for Failure Prediction of Overhead Line

    NASA Astrophysics Data System (ADS)

    Ma, Yan; Zhu, Wenbing; Yao, Jinxia; Gu, Chao; Bai, Demeng; Wang, Kun

    2017-01-01

    In this paper, we give an approach of transforming time series data with different time granularities into the same plane, which is the basis of further association analysis. We focus on the application of overhead line tripping. First all the relative state variables with line tripping are collected into our big data platform. We collect line account, line fault, lightning, power load and meteorological data. Second we respectively pre-process the five kinds of data to guarantee the integrality of data and simplicity of analysis. We use a representation way combining the aggregated representation and trend extraction methods, which considers both short term variation and long term trend of time sequence. Last we use extensive experiments to demonstrate that the proposed time granularity transformation approach not only lets multiple variables analysed on the same plane, but also has a high prediction accuracy and low running time no matter for SVM or logistic regression algorithm.

  8. Predicting success or failure of immunotherapy for cancer: insights from a clinically applicable mathematical model.

    PubMed

    Babbs, Charles F

    2012-01-01

    The objective of this study was to create a clinically applicable mathematical model of immunotherapy for cancer and use it to explore differences between successful and unsuccessful treatment scenarios. The simplified predator-prey model includes four lumped parameters: tumor growth rate, g; immune cell killing efficiency, k; immune cell signaling factor, λ; and immune cell half-life decay, μ. The predator-prey equations as functions of time, t, for normalized tumor cell numbers, y, (the prey) and immunocyte numbers, ×, (the predators) are: dy/dt = gy - kx and dx/dt = λxy - μx. A parameter estimation procedure that capitalizes on available clinical data and the timing of clinically observable phenomena gives mid-range benchmarks for parameters representing the unstable equilibrium case in which the tumor neither grows nor shrinks. Departure from this equilibrium results in oscillations in tumor cell numbers and in many cases complete elimination of the tumor. Several paradoxical phenomena are predicted, including increasing tumor cell numbers prior to a population crash, apparent cure with late recurrence, one or more cycles of tumor growth prior to eventual tumor elimination, and improved tumor killing with initially weaker immune parameters or smaller initial populations of immune cells. The model and the parameter estimation techniques are easily adapted to various human cancers that evoke an immune response. They may help clinicians understand and predict certain strange and unexpected effects in the world of tumor immunity and lead to the design of clinical trials to test improved treatment protocols for patients.

  9. Effect of High-Flow Nasal Cannula versus Conventional Oxygen Therapy for Patients with Thoracoscopic Lobectomy after Extubation.

    PubMed

    Yu, Yuetian; Qian, Xiaozhe; Liu, Chunyan; Zhu, Cheng

    2017-01-01

    Objective. To investigate whether high-flow nasal cannula (HFNC) oxygen therapy is superior to conventional oxygen therapy for reducing hypoxemia and postoperative pulmonary complications (PPC) in patients with thoracoscopic lobectomy after extubation. Methods. Patients with intermediate to high risk for PPC were enrolled in this study. Subjects were randomly assigned to HFNC group (HFNCG) or conventional oxygen group (COG) following extubation. Arterial blood samples were collected after extubation at 1, 2, 6, 12, 24, 48, and 72 h. Patients with postoperative hypoxemia and PPC were recorded. Adverse events were also documented. Results. Totally 110 patients were randomly assigned to HFNCG (n = 56) and COG (n = 54). The occurrence rate of hypoxemia in COG was twice more than that in HFNCG (29.62% versus 12.51%, P < 0.05) and PaO2, PaO2/FiO2, and SaO2/FiO2 were significantly improved in HFNCG (P < 0.05) in the first 72 h following extubation. Respiratory rate and incidence of reintubation as well as needing noninvasive ventilation were also decreased in HFNCG (P < 0.05), whereas the incidence of pneumonia and atelectasis were similar (P > 0.05). Adverse effects as throat and nasal pain occurred more frequently in COG. Conclusions. HFNC application improves oxygenation and reduces the risk of reintubation following thoracoscopic lobectomy but cannot decrease the incidence of PPC.

  10. Effect of High-Flow Nasal Cannula versus Conventional Oxygen Therapy for Patients with Thoracoscopic Lobectomy after Extubation

    PubMed Central

    Yu, Yuetian; Qian, Xiaozhe; Liu, Chunyan

    2017-01-01

    Objective. To investigate whether high-flow nasal cannula (HFNC) oxygen therapy is superior to conventional oxygen therapy for reducing hypoxemia and postoperative pulmonary complications (PPC) in patients with thoracoscopic lobectomy after extubation. Methods. Patients with intermediate to high risk for PPC were enrolled in this study. Subjects were randomly assigned to HFNC group (HFNCG) or conventional oxygen group (COG) following extubation. Arterial blood samples were collected after extubation at 1, 2, 6, 12, 24, 48, and 72 h. Patients with postoperative hypoxemia and PPC were recorded. Adverse events were also documented. Results. Totally 110 patients were randomly assigned to HFNCG (n = 56) and COG (n = 54). The occurrence rate of hypoxemia in COG was twice more than that in HFNCG (29.62% versus 12.51%, P < 0.05) and PaO2, PaO2/FiO2, and SaO2/FiO2 were significantly improved in HFNCG (P < 0.05) in the first 72 h following extubation. Respiratory rate and incidence of reintubation as well as needing noninvasive ventilation were also decreased in HFNCG (P < 0.05), whereas the incidence of pneumonia and atelectasis were similar (P > 0.05). Adverse effects as throat and nasal pain occurred more frequently in COG. Conclusions. HFNC application improves oxygenation and reduces the risk of reintubation following thoracoscopic lobectomy but cannot decrease the incidence of PPC. PMID:28298878

  11. [Non-verbal communication of patients submitted to heart surgery: from awaking after anesthesia to extubation].

    PubMed

    Werlang, Sueli da Cruz; Azzolin, Karina; Moraes, Maria Antonieta; de Souza, Emiliane Nogueira

    2008-12-01

    Preoperative orientation is an essential tool for patient's communication after surgery. This study had the objective of evaluating non-verbal communication of patients submitted to cardiac surgery from the time of awaking from anesthesia until extubation, after having received preoperative orientation by nurses. A quantitative cross-sectional study was developed in a reference hospital of the state of Rio Grande do Sul, Brazil, from March to July 2006. Data were collected in the pre and post operative periods. A questionnaire to evaluate non-verbal communication on awaking from sedation was applied to a sample of 100 patients. Statistical analysis included Student, Wilcoxon, and Mann Whittney tests. Most of the patients responded satisfactorily to non-verbal communication strategies as instructed on the preoperative orientation. Thus, non-verbal communication based on preoperative orientation was helpful during the awaking period.

  12. Post Extubation Bronchospasm in an Undiagnosed Case of Ascariasis: Anaesthetic Challenges

    PubMed Central

    Gehlot, Ravindra; Kumari, Indira; Verma, Virendra; Bidwaikar, Aditya

    2017-01-01

    One of the most prevalent parasitic infestation is ascariasis which poses a great challenge to both the person being infested with and the treating medical team. We present here a case of round worm (Ascaris lumbricoides) infestation. A 40-year-old male, weighing 60 kg, diagnosed as perforation peritonitis, was scheduled for emergency exploratory laparotomy. The round worm was crawling out from duodenal perforation vent during laparotomy confirming the infestation. Patient later developed bronchospasm in post-extubation period and was managed accordingly. Surprisingly the patient expelled an adult worm in the next morning. This report highlights the importance of anticipating complications (i.e., airway obstruction, bronchospasm, etc.,) in an undiagnosed case of round worm infestation, especially if routine investigations were within normal limits. PMID:28384964

  13. Clinical skills: a care plan approach to nurse-led extubation.

    PubMed

    De, Diana

    Long-term mechanical ventilation (in patients who require mechanical ventilation for longer than 24 hours) has been associated with prolonged anxiety, chest infections and high mortality rates. Prolonged mechanical ventilation is also costly, as it tends to be carried out in critical care environments which require high levels of staffing. Therefore, it would appear to be of great benefit to patients, relatives and all multidisciplinary healthcare professionals concerned in delivering respiratory care if patient ventilation was kept as brief as possible. Current opinions seem to suggest that nurses can be the key players in reducing the time on a mechanical ventilator for patients and can take the lead on the extubation process of ventilatory weaning.

  14. Why achievement motivation predicts success in business but failure in politics: the importance of personal control.

    PubMed

    Winter, David G

    2010-12-01

    Several decades of research have established that implicit achievement motivation (n Achievement) is associated with success in business, particularly in entrepreneurial or sales roles. However, several political psychology studies have shown that achievement motivation is not associated with success in politics; rather, implicit power motivation often predicts political success. Having versus lacking control may be a key difference between business and politics. Case studies suggest that achievement-motivated U.S. presidents and other world leaders often become frustrated and thereby fail because of lack of control, whereas power-motivated presidents develop ways to work with this inherent feature of politics. A reevaluation of previous research suggests that, in fact, relationships between achievement motivation and business success only occur when control is high. The theme of control is also prominent in the development of achievement motivation. Cross-national data are also consistent with this analysis: In democratic industrialized countries, national levels of achievement motivation are associated with strong executive control. In countries with low opportunity for education (thus fewer opportunities to develop a sense of personal control), achievement motivation is associated with internal violence. Many of these manifestations of frustrated achievement motivation in politics resemble authoritarianism. This conclusion is tested by data from a longitudinal study of 113 male college students, showing that high initial achievement motivation combined with frustrated desires for control is related to increases in authoritarianism (F-scale scores) during the college years. Implications for the psychology of leadership and practical politics are discussed.

  15. Predictive value of advanced glycation end products for the development of post-infarction heart failure: a preliminary report

    PubMed Central

    2012-01-01

    Background Since post-infarction heart failure (HF) determines a great morbidity and mortality, and given the physiopathology implications of advanced glycation end products (AGE) in the genesis of myocardial dysfunction, it was intended to analyze the prognostic value of these molecules in order to predict post-infarction HF development. Methods A prospective clinical study in patients after first acute coronary syndrome was conducted. The follow-up period was consisted in 1 year. In 194 patients consecutively admitted in the coronary unit for myocardial infarct fluorescent AGE levels were measured. The association between glycaemic parameters and the development of post-infarction HF were analyzed in those patients. Finally, we identified the variables with independent predictor value by performing a multivariate analysis of Hazard ratio for Cox regression. Results Eleven out of 194 patients (5.6%) developed HF during follow-up (median: 1.0 years [0.8 - 1.5 years]). Even though basal glucose, fructosamine and glycated haemoglobin were significant predictive factors in the univariate analysis, after being adjusted by confounding variables and AGE they lost their statistical signification. Only AGE (Hazard Ratio 1.016, IC 95%: 1.006-1.026; p<0,001), together with NT-proBNP and the infarct extension were predictors for post-infarction HF development, where AGE levels over the median value 5-fold increased the risk of HF development during follow-up. Conclusions AGE are an independent marker of post-infarction HF development risk. PMID:22909322

  16. A physically-based method for predicting peak discharge of floods caused by failure of natural and constructed earthen dams

    USGS Publications Warehouse

    Walder, J.S.

    1997-01-01

    We analyse a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V/ D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether ?? > 1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.

  17. Failure of glutamate dehydrogenase system to predict oxygenation state of human skeletal muscle.

    PubMed

    Katz, A; Spencer, M K; Sahlin, K

    1990-07-01

    In a recent study, the total tissue contents of glutamate (Glu), ammonium (NH+4), and 2-oxoglutarate (2-OG) were used to estimate changes in the mitochondrial redox state ([NAD+]/[NADH]) of contracting skeletal muscle with intact circulation [Am. J. Physiol. 253 (Cell Physiol. 22): C263-C268, 1987]. These metabolites participate in the glutamate dehydrogenase (GDH) reaction, which, based on a number of assumptions, theoretically enables calculation of the mitochondrial redox state as follows (brackets indicate concentrations): [NAD+]/[NADH] = ([NH+4] [2-OG])/[( Glu]Kapp), where Kapp is the apparent equilibrium constant for GDH. The purpose of this study was to determine whether changes in the total tissue contents of Glu, NH+4, and 2-OG could be used to predict a reduction of the mitochondrial redox state in anoxic skeletal muscle. Anoxia was induced in the quadriceps femoris muscle by 10 min of circulatory occlusion (low metabolic rate) and isometric contraction to fatigue (high metabolic rate). The mean (+/- SE) value for the metabolite ratio ([NH+4][2-OG]/[Glu]) at rest was 6 +/- 3 mmol/kg dry wt (x 10(-4]. No significant change occurred after circulatory occlusion (4 +/- 2 x 10(-4); P greater than 0.05), whereas an almost 60-fold increase was observed after isometric contraction (P less than 0.05). Because the muscle was anoxic under both conditions, a significant decrease in the metabolite ratio should have occurred. These data demonstrate that changes in total tissue contents of Glu, NH+4, and 2-OG cannot be used to estimate changes in the redox and oxygenation state of mitochondria in intact human skeletal muscle.

  18. Metabolic Response on Post-therapy FDG-PET Predicts Patterns of Failure After Radiotherapy for Cervical Cancer

    SciTech Connect

    Schwarz, Julie K.; Siegel, Barry A.; Dehdashti, Farrokh; Grigsby, Perry W.

    2012-05-01

    Purpose: To determine the patterns of failure in patients with cervical cancer treated with definitive radiotherapy and evaluated for metabolic response with early posttherapy {sup 18}F-fluorodeoxyglucose positron emission tomography (FDG-PET). Methods and Materials: The records of 238 patients with cervical cancer were reviewed. All patients were treated with a combination of external radiotherapy and intracavitary brachytherapy. Two hundred and nineteen patients (92%) received concurrent chemotherapy. All patients underwent pretreatment FDG-PET, and posttherapy FDG-PET was performed within 8-16 weeks of the completion of radiotherapy. Posttherapy FDG-PET results were categorized as complete metabolic response (CMR), partial metabolic response (PMR), and progressive disease (PD). Failure patterns were categorized as none, isolated local failure (central pelvis {+-} pelvic lymph nodes), distant failure, or combined local plus distant failure. Results: Of the 91 patients (38%) who had a recurrence, 22 had isolated local failures, and 69 had distant failures (49 distant failures and 20 combined local plus distant failures). Of the 173 patients with a CMR, 40 (23%) experienced treatment failure. All 25 patients with PD experienced treatment failure, which was distant in 24 patients (96%). Among the 40 patients with PMR, no failure has been observed for 14 patients (35%). Of the 26 failures within the PMR group, 15 (58%) were limited to the pelvis. Differences in the patterns of failure between the three groups (CMR, PMR, PD) were statistically significant (chi-square test; p < 0.0001). Conclusions: The majority of failures after definitive radiotherapy for cervical cancer include distant failures, even in the setting of concurrent chemotherapy. PMR within the cervix or lymph nodes is more commonly associated with isolated local recurrence.

  19. Right atrial volume by cardiovascular magnetic resonance predicts mortality in patients with heart failure with reduced ejection fraction

    PubMed Central

    Ivanov, Alexander; Mohamed, Ambreen; Asfour, Ahmed; Ho, Jean; Khan, Saadat A.; Chen, Onn; Klem, Igor; Ramasubbu, Kumudha; Brener, Sorin J.; Heitner, John F.

    2017-01-01

    Background Right Atrial Volume Index (RAVI) measured by echocardiography is an independent predictor of morbidity in patients with heart failure (HF) with reduced ejection fraction (HFrEF). The aim of this study is to evaluate the predictive value of RAVI assessed by cardiac magnetic resonance (CMR) for all-cause mortality in patients with HFrEF and to assess its additive contribution to the validated Meta-Analysis Global Group in Chronic heart failure (MAGGIC) score. Methods and results We identified 243 patients (mean age 60 ± 15; 33% women) with left ventricular ejection fraction (LVEF) ≤ 35% measured by CMR. Right atrial volume was calculated based on area in two- and four -chamber views using validated equation, followed by indexing to body surface area. MAGGIC score was calculated using online calculator. During mean period of 2.4 years 33 patients (14%) died. The mean RAVI was 53 ± 26 ml/m2; significantly larger in patients with than without an event (78.7±29 ml/m2 vs. 48±22 ml/m2, p<0.001). RAVI (per ml/m2) was an independent predictor of mortality [HR = 1.03 (1.01–1.04), p = 0.001]. RAVI has a greater discriminatory ability than LVEF, left atrial volume index and right ventricular ejection fraction (RVEF) (C-statistic 0.8±0.08 vs 0.55±0.1, 0.62±0.11, 0.68±0.11, respectively, all p<0.02). The addition of RAVI to the MAGGIC score significantly improves risk stratification (integrated discrimination improvement 13%, and category-free net reclassification improvement 73%, both p<0.001). Conclusion RAVI by CMR is an independent predictor of mortality in patients with HFrEF. The addition of RAVI to MAGGIC score improves mortality risk stratification. PMID:28369148

  20. Point-of-Care, Ultraportable Echocardiography Predicts Diuretic Response in Patients Admitted with Acute Decompensated Heart Failure

    PubMed Central

    Krishnan, Dena K.; Pawlaczyk, Barbara; McCullough, Peter A.; Enright, Susan; Kunadi, Arvind; Vanhecke, Thomas E.

    2016-01-01

    BACKGROUND Routine management of patients with acute decompensated heart failure (ADHF) requires careful attentiveness to fluid status and diuretic treatment efficacy. New advances in ultrasound have made ultraportable echocardiography (UE) available to physicians for point-of-care use. The purpose of this study is to explore physiologic measures of intravascular fluid volume derived from UE and explore predictors of diuretic response in ADHF. METHODS Various echocardiography imaging measurements, particularly diameter and collapse of inferior vena cava (IVC), were collected from 77 patients admitted with a primary diagnosis of ADHF. Patients were divided into two groups based on whether or not they achieved a net negative fluid output of 3 L within 48 hours. The demographic information, serum laboratory markers, and physical characteristics of the subjects were obtained to correlate with daily ultrasound measurements. Univariate and multivariate analyses were used to compare diuretic “responders” to “nonresponders.” RESULTS A negative change in the IVC diameter at 48 hours was robust in prediction of diuretic response. For every 1 mm decrease in the IVC diameter at 48 hours, there was an odds ratio of 1.62 (95% CI: 1.20–2.19) for responding to diuretic therapy independent of other variables including baseline renal filtration function and blood B-type natriuretic peptide. CONCLUSION Assessment of central venous pressure as a proxy for passive renal congestion independently predicts initial diuretic response in ADHF. Future research is needed to further understand the individual variation in response to loop diuresis and to identify optimal treatment approaches that utilize anatomic and physiologic measures such as venous ultrasound. PMID:28008296

  1. Increased Platelet-to-Lymphocyte Ratios and Low Relative Lymphocyte Counts Predict Appropriate Shocks in Heart Failure Patients with ICDs

    PubMed Central

    Balci, Kevser Gülcihan; Balci, Mustafa Mücahit; Arslan, Ugur; Açar, Burak; Maden, Orhan; Selcuk, Hatice; Selcuk, Timur

    2016-01-01

    Background Platelet-to-lymphocyte ratio (PLR) and relative lymphocyte count (L%) are commonly available tests that can be obtained from complete blood count. The aim of this study was to investigate the association between appropriate defibrillator therapy and PLR, and whether decreased lymphocyte count may predict appropriate implantable cardioverter defibrillator (ICD) shocks in heart failure (HF) patients. Methods A total of 147 patients with ischemic or non-ischemic HF who underwent ICD implantation for primary prevention were enrolled in this study. Peripheral venous blood samples were drawn on the same day as ICD implantation. White blood cell counts with differentials, red blood cell indices, and platelet counts were calculated with an automated blood cell counter. All patients were evaluated according to the presence of appropriate ICD therapy. Results Baseline ejection fraction was significantly lower in the appropriate shock received group (p = 0.040). Median PLR was significantly higher and L% was significantly lower in the appropriate shock received group (p < 0.001). In both ischemic and non-ischemic HF groups, median L% was significantly lower in the appropriate shock received group (p < 0.001; p = 0.006, respectively). In multivariable logistic regression analysis, only L% showed a strong association with appropriate shock therapy (p < 0.001). Conclusions Higher PLRs are related to appropriate shocks in patients that received ICD with lower EF. Furthermore, decreased L% is independently associated with appropriate shocks in HF. PMID:27713602

  2. Application of the Sequential Organ Failure Assessment Score to predict outcome in critically ill dogs: preliminary results.

    PubMed

    Ripanti, D; Dino, G; Piovano, G; Farca, A

    2012-08-01

    In human medicine the Sequential Organ Failure Assessment (SOFA) score is one of the most commonly organ dysfunction scoring systems used to assess critically ill patients and to predict the outcome in Intensive Care Units (ICUs). It is composed of scores from six organ systems (respiratory, cardiovascular, hepatic, coagulation, renal, and neurological) graded according to the degree of the dysfunction. The aim of the current study was to describe the applicability of the SOFA score in assessing the outcome of critically ill dogs. A total of 45 dogs admitted to the ICU was enrolled. Among these, 40 dogs completed the study: 50 % survived and left the veterinary clinic. The SOFA score was computed for each dog every 24 hours for the first 3 days of ICU stay, starting on the day of admission. A statistically significant correlation between SOFA score and death or survival was found. Most of the dogs showing an increase of the SOFA score in the first 3 days of hospitalization died, whereas the dogs with a decrease of the score survived. These results suggest that the SOFA score system could be considered a useful indicator of prognosis in ICUs hospitalized dogs.

  3. Kansas City Cardiomyopathy Questionnaire Utility in Prediction of 30-Day Readmission Rate in Patients with Chronic Heart Failure

    PubMed Central

    Gui, Junhong; Zhu, Xiang; Malhotra, Divyanshu; Li, Shenjing; Virkram, Fnu; Chada, Aditya; Jiang, Haibing

    2016-01-01

    Background. Heart failure (HF) is one of the most common diagnoses associated with hospital readmission. We designed this prospective study to evaluate whether Kansas City Cardiomyopathy Questionnaire (KCCQ) score is associated with 30-day readmission in patients hospitalized with decompensated HF. Methods and Results. We enrolled 240 patients who met the study criteria. Forty-eight (20%) patients were readmitted for decompensated HF within thirty days of hospital discharge, and 192 (80%) patients were not readmitted. Compared to readmitted patients, nonreadmitted patients had a higher average KCCQ score (40.8 versus 32.6, P = 0.019) before discharge. Multivariate analyses showed that a high KCCQ score was associated with low HF readmission rate (adjusted OR = 0.566, P = 0.022). The c-statistic for the base model (age + gender) was 0.617. The combination of home medication and lab tests on the base model resulted in an integrated discrimination improvement (IDI) increase of 3.9%. On that basis, the KCQQ further increased IDI of 2.7%. Conclusions. The KCCQ score determined before hospital discharge was significantly associated with 30-day readmission rate in patients with HF, which may provide a clinically useful measure and could significantly improve readmission prediction reliability when combined with other clinical components. PMID:27872790

  4. Prediction of scuffing failure based on competitive kinetics of oxide formation and removal: Application to lubricated sliding of AISI 52100 steel on steel

    NASA Astrophysics Data System (ADS)

    Cutiongco, Eric C.; Chung, Yip-Wah

    1994-07-01

    A method for predicting scuffing failure based on the competitive kinetics of oxide formation and removal has been developed and applied to the sliding of AISI 52100 steel on steel with poly-alpha-olefin as the lubricant. Oxide formation rates were determining using static oxidation tests on coupons of 52100 steel covered with poly-alpha-olefin at temperatures of 140 C to 250 C. Oxide removal rates were determined at different combinations of initial average nominal contact pressures (950 MPa to 1578 MPa) and sliding velocities (0.4 m/s to 1.8 m/s) using a ball-on-disk vacuum tribotester. The nominal asperity flash temperatures generated during the wear tests were calculated and the temperatures corresponding to the intersection of the the Arrhenius plots of oxide formation and removal rates were determined and taken as the critical failure temperatures. The pressure-velocity failure transition diagram was constructed by plotting the critical failure temperatures along isotherms of average nominal asperity flash temperatures calculated at different combinations of contact stress and sliding speed. The predicted failure transition curve agreed well with experimental scuffing data.

  5. Individual Differences in Self-Regulatory Failure and Menstrual Dysfunction Predict Upper Respiratory Infection Symptoms and Antibody Response to Flu Immunization

    PubMed Central

    Strauman, Timothy J.; Coe, Christopher L.; McCrudden, Megan C.; Vieth, Angela Z.; Kwapil, Lori

    2008-01-01

    Prior research indicates that cognitive priming manipulations that activate personal goals acutely increase or decrease natural killer cell cytotoxicity depending on whether individuals see themselves as making or failing to make progress toward their goals. Those findings in a laboratory setting revealed a psychobiological pathway whereby experiences of failure can influence health, but did not assess the impact of chronic perceived success/failure in goal pursuit on actual health outcomes. Three new studies investigated whether individual differences in perceived failure to attain personal goals influenced the self-reported symptoms of upper respiratory infections (URIs) as well as antibody response to flu immunization. Based on pilot data in young women, it also was hypothesized that the occurrence of menstrual dysfunction might interact with goal pursuit failure to more specifically predict cold and flu symptoms and optimal responses to vaccination. Perceived failure to attain goals did predict the reporting of URI symptoms as well as antibody levels post-immunization, both alone and in combination with menstrual dysfunction. PMID:18294813

  6. Role of galectin-3 and plasma B type-natriuretic peptide in predicting prognosis in discharged chronic heart failure patients.

    PubMed

    Feola, Mauro; Testa, Marzia; Leto, Laura; Cardone, Marco; Sola, Mario; Rosso, Gian Luca

    2016-06-01

    Galectin-3 demonstrated to be a robust independent marker of cardiovascular mid-term (18-month) outcome in heart failure (HF) patients. The objective of this study was to analyze the value of a predischarged determination of plasma galectin-3 alone and with plasma brain natriuretic peptide (BNP) in predicting mid-term outcome in frequent-flyers (FF) HF (≥2 hospitalization for HF/year)/dead patients discharged after an acute decompensated HF (ADHF) episode.All FF chronic HF subjects discharged alive after an ADHF were enrolled. All patients underwent a determination of BNP and galectin-3, a 6-minute walk test, and an echocardiogram within 48 hours upon hospital discharge. Death by any cause, cardiac transplantation, and worsening HF requiring readmission to hospital were considered cardiovascular events.Eighty-three patients (67 males, age 73.2 ± 8.6 years old) were analyzed (mean follow-up 11.6 ± 5.2 months; range 4-22 months). During the follow-up 38 events (45.7%) were scheduled: (13 cardiac deaths, 35 rehospitalizations for ADHF). According to medical history, in 33 patients (39.8%) a definition of FF HF patients was performed (range 2-4 hospitalization/year). HF patients who suffered an event (FF or death) demonstrated more impaired ventricular function (P = 0.037), higher plasma BNP (P = 0.005), and Gal-3 at predischarge evaluation (P = 0.027). Choosing adequate cut-off points (BNP ≥ 500 pg/mL and Gal-3 ≥ 17.6 ng/mL), the Kaplan-Meier curves depicted the powerful stratification using BNP + Gal-3 in predicting clinical course at mid-term follow-up (log rank 5.65; P = 0.017).Adding Gal-3 to BNP, a single predischarge strategy testing seemed to obtain a satisfactorily predictive value in alive HF patients discharged after an ADHF episode.

  7. Plasma nevirapine concentrations predict virological and adherence failure in Kenyan HIV-1 infected patients with extensive antiretroviral treatment exposure.

    PubMed

    Kimulwo, Maureen J; Okendo, Javan; Aman, Rashid A; Ogutu, Bernhards R; Kokwaro, Gilbert O; Ochieng, Dorothy J; Muigai, Anne W T; Oloo, Florence A; Ochieng, Washingtone

    2017-01-01

    Treatment failure is a key challenge in the management of HIV-1 infection. We conducted a mixed-model survey of plasma nevirapine (NVP) concentrations (cNVP) and viral load in order to examine associations with treatment and adherence outcomes among Kenyan patients on prolonged antiretroviral therapy (ART). Blood plasma was collected at 1, 4 and 24 hours post-ART dosing from 58 subjects receiving NVP-containing ART and used to determine cNVP and viral load (VL). Median duration of treatment was 42 (range, 12-156) months, and 25 (43.1%) of the patients had virologic failure (VF). cNVP was significantly lower for VF than non- VF at 1hr (mean, 2,111ng/ml vs. 3,432ng/ml, p = 0.003) and at 4hr (mean 1,625ng/ml vs. 3,999ng/ml, p = 0.001) but not at 24hr post-ART dosing. Up to 53.4%, 24.1% and 22.4% of the subjects had good, fair and poor adherence respectively. cNVP levels peaked and were > = 3μg.ml at 4 hours in a majority of patients with good adherence and those without VF. Using a threshold of 3μg/ml for optimal therapeutic nevirapine level, 74% (43/58), 65.5% (38/58) and 86% (50/58) of all patients had sub-therapeutic cNVP at 1, 4 and 24 hours respectively. cNVP at 4 hours was associated with adherence (p = 0.05) and virologic VF (p = 0.002) in a chi-square test. These mean cNVP levels differed significantly in non-parametric tests between adherence categories at 1hr (p = 0.005) and 4hrs (p = 0.01) and between ART regimen categories at 1hr (p = 0.004) and 4hrs (p<0.0001). Moreover, cNVP levels correlated inversely with VL (p< = 0.006) and positively with adherence behavior. In multivariate tests, increased early peak NVP (cNVP4) was independently predictive of lower VL (p = 0.002), while delayed high NVP peak (cNVP24) was consistent with increased VL (p = 0.033). These data strongly assert the need to integrate plasma concentrations of NVP and that of other ART drugs into routine ART management of HIV-1 patients.

  8. Plasma nevirapine concentrations predict virological and adherence failure in Kenyan HIV-1 infected patients with extensive antiretroviral treatment exposure

    PubMed Central

    Kimulwo, Maureen J.; Okendo, Javan; Aman, Rashid A.; Ogutu, Bernhards R.; Kokwaro, Gilbert O.; Ochieng, Dorothy J.; Muigai, Anne W. T.; Oloo, Florence A.

    2017-01-01

    Treatment failure is a key challenge in the management of HIV-1 infection. We conducted a mixed-model survey of plasma nevirapine (NVP) concentrations (cNVP) and viral load in order to examine associations with treatment and adherence outcomes among Kenyan patients on prolonged antiretroviral therapy (ART). Blood plasma was collected at 1, 4 and 24 hours post-ART dosing from 58 subjects receiving NVP-containing ART and used to determine cNVP and viral load (VL). Median duration of treatment was 42 (range, 12–156) months, and 25 (43.1%) of the patients had virologic failure (VF). cNVP was significantly lower for VF than non- VF at 1hr (mean, 2,111ng/ml vs. 3,432ng/ml, p = 0.003) and at 4hr (mean 1,625ng/ml vs. 3,999ng/ml, p = 0.001) but not at 24hr post-ART dosing. Up to 53.4%, 24.1% and 22.4% of the subjects had good, fair and poor adherence respectively. cNVP levels peaked and were > = 3μg.ml at 4 hours in a majority of patients with good adherence and those without VF. Using a threshold of 3μg/ml for optimal therapeutic nevirapine level, 74% (43/58), 65.5% (38/58) and 86% (50/58) of all patients had sub-therapeutic cNVP at 1, 4 and 24 hours respectively. cNVP at 4 hours was associated with adherence (p = 0.05) and virologic VF (p = 0.002) in a chi-square test. These mean cNVP levels differed significantly in non-parametric tests between adherence categories at 1hr (p = 0.005) and 4hrs (p = 0.01) and between ART regimen categories at 1hr (p = 0.004) and 4hrs (p<0.0001). Moreover, cNVP levels correlated inversely with VL (p< = 0.006) and positively with adherence behavior. In multivariate tests, increased early peak NVP (cNVP4) was independently predictive of lower VL (p = 0.002), while delayed high NVP peak (cNVP24) was consistent with increased VL (p = 0.033). These data strongly assert the need to integrate plasma concentrations of NVP and that of other ART drugs into routine ART management of HIV-1 patients. PMID:28235021

  9. Using a multi-parameter monitoring methodology to predict failures in the cryogenic plant of the cold neutron source at Australia's OPAL reactor

    NASA Astrophysics Data System (ADS)

    Lu, Weijian; Thiering, Russell

    2012-06-01

    A 5 kW Brayton-cycle helium refrigeration plant provides cooling at 20 K to the Cold Neutron Source (CNS) at Australia's OPAL Reactor. During several years of operation to the present day, the plant has experienced an unusually high number of turbine and compressor failures. The root cause for some of the failures is known, but for others remains to be determined. All of the failures were catastrophic without any prior warning from standard industrial monitoring based on singular process variables such as temperature, pressure and vibration. The failures and the down time they caused have been very costly. As the operator of the plant, we have developed a multi-parameter monitoring (MPM) methodology to track the performance of the plant. The methodology utilises indicators obtained from a combination of process variables based on their thermodynamic relations. By studying the historical trends of appropriate indicators, especially during the past failures, we have found some indicators that would be able to improve our predictive capability so that we can avoid similar failures in the future.

  10. Predicting from Earlier Substance Abuse and Earlier Grade Point Average to Failure to Graduate from High School.

    ERIC Educational Resources Information Center

    Friedman, Alfred S.; And Others

    1985-01-01

    Examined failure to graduate from high school as a function of grade point average and substance abuse among Phildelphia high school students (N=427). Results of multiple regression analyses indicated that the gradepoint averages are more powerful predictors to eventual failure to graduate than are "Drug Severity Index" scores. (BL)

  11. Metabolic Rates of ATP Transfer Through Creatine Kinase (CK Flux) Predict Clinical Heart Failure Events and Death

    PubMed Central

    Bottomley, Paul A.; Panjrath, Gurusher S.; Lai, Shenghan; Hirsch, Glenn A.; Wu, Katherine; Najjar, Samer S.; Steinberg, Angela; Gerstenblith, Gary; Weiss, Robert G.

    2015-01-01

    Morbidity and mortality from heart failure (HF) are high, and current risk stratification approaches for predicting HF progression are imperfect. Adenosine triphosphate (ATP) is required for normal cardiac contraction, and abnormalities in creatine kinase (CK) energy metabolism, the primary myocardial energy reserve reaction, have been observed in experimental and clinical HF. However, the prognostic value of abnormalities in ATP production rates through CK in human HF has not been investigated. Fifty-eight HF patients with nonischemic cardiomyopathy underwent 31P magnetic resonance spectroscopy (MRS) to quantify cardiac high-energy phosphates and the rate of ATP synthesis through CK (CK flux) and were prospectively followed for a median of 4.7 years. Multiple-event analysis (MEA) was performed for HF-related events including all-cause and cardiac death, HF hospitalization, cardiac transplantation, and ventricular-assist device placement. Among baseline demographic, clinical, and metabolic parameters, MEA identified four independent predictors of HF events: New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF), African-American race, and CK flux. Reduced myocardial CK flux was a significant predictor of HF outcomes, even after correction for NYHA class, LVEF, and race. For each increase in CK flux of 1 μmol g−1 s−1, risk of HF-related composite outcomes decreased by 32 to 39%. These findings suggest that reduced CK flux may be a potential HF treatment target. Newer imaging strategies, including noninvasive 31P MRS that detect altered ATP kinetics, could thus complement risk stratification in HF and add value in conditions involving other tissues with high energy demands, including skeletal muscle and brain. PMID:24337482

  12. Additive clinical value of serum brain-derived neurotrophic factor for prediction of chronic heart failure outcome.

    PubMed

    Kadowaki, Shinpei; Shishido, Tetsuro; Honda, Yuki; Narumi, Taro; Otaki, Yoichiro; Kinoshita, Daisuke; Nishiyama, Satoshi; Takahashi, Hiroki; Arimoto, Takanori; Miyamoto, Takuya; Watanabe, Tetsu; Kubota, Isao

    2016-04-01

    The importance of the central nervous system in cardiovascular events has been recognized. Recently, brain-derived neurotrophic factor (BDNF), a member of the neurotrophic factor family, is involved in depression mechanisms and also in stress and anxiety. Because BDNF is reported about cardioprotective role, we elucidated whether BDNF is associated with cardiovascular events in patients with chronic heart failure (CHF). We examined serum BDNF levels in 134 patients with CHF and 23 control subjects. The patients were followed to register cardiac events for a median of 426 days. BDNF was significantly lower in CHF patients than in control subjects (25.8 ± 8.4 vs 14.7 ± 8.4, P < 0.0001). Serum BDNF was also lower in patients with cardiac events than in event-free patients (16.1 ± 8.0 vs 12.5 ± 8.5, P < 0.0001). The cutoff value of BDNF was determined by performing receiver operating characteristic curve analysis. Kaplan-Meier analysis demonstrated that patients with low levels of BDNF experienced higher rates of cardiac events than those with high levels of BDNF. Multivariate Cox hazard analysis demonstrated that low BDNF levels (≤12.4 ng/mL) were an independent prognostic factor for cardiac events (hazard ratio 2.932, 95 % confidence interval 1.622-5.301; P = 0.0004). Adding levels of BDNF to the model with BNP levels, age, and eGFR for the prediction of cardiac events yielded significant net reclassification improvement of 0.429 (P < 0.001) and an integrated discrimination improvement of 0.101 (P < 0.001). Low serum BDNF levels were found in patients with CHF, and these levels were found to be independently associated with an increased risk of cardiac events.

  13. Predicting Length of Stay among Patients Discharged from the Emergency Department—Using an Accelerated Failure Time Model

    PubMed Central

    Chen, Hsiu-Hsi; Chang, Shu-Hui; Tang, Petrus; Pan, Shin-Liang; Yen, Amy Ming-Fang; Chiu, Te-Fa

    2017-01-01

    Background Emergency department (ED) crowding continues to be an important health care issue in modern countries. Among the many crucial quality indicators for monitoring the throughput process, a patient’s length of stay (LOS) is considered the most important one since it is both the cause and the result of ED crowding. The aim of this study is to identify and quantify the influence of different patient-related or diagnostic activities-related factors on the ED LOS of discharged patients. Methods This is a retrospective electronic data analysis. All patients who were discharged from the ED of a tertiary teaching hospital in 2013 were included. A multivariate accelerated failure time model was used to analyze the influence of the collected covariates on patient LOS. Results A total of 106,206 patients were included for analysis with an overall medium ED LOS of 1.46 (interquartile range = 2.03) hours. Among them, 96% were discharged by a physician, 3.5% discharged against medical advice, 0.5% left without notice, and only 0.02% left without being seen by a physician. In the multivariate analysis, increased age (>80 vs <20, time ratio (TR) = 1.408, p<0.0001), higher acuity level (triage level I vs. level V, TR = 1.343, p<0.0001), transferred patients (TR = 1.350, p<0.0001), X-rays obtained (TR = 1.181, p<0.0001), CT scans obtained (TR = 1.515, p<0.0001), laboratory tests (TR = 2.654, p<0.0001), consultation provided (TR = 1.631, p<0.0001), observation provided (TR = 8.435, p<0.0001), critical condition declared (TR = 1.205, p<0.0001), day-shift arrival (TR = 1.223, p<0.0001), and an increased ED daily census (TR = 1.057, p<0.0001) lengthened the ED LOS with various effect sizes. On the other hand, male sex (TR = 0.982, p = 0.002), weekend arrival (TR = 0.928, p<0.0001), and adult non-trauma patients (compared with pediatric non-trauma, TR = 0.687, p<0.0001) were associated with shortened ED LOS. A prediction diagram was made accordingly and compared with the actual

  14. Heart Failure

    MedlinePlus

    ... version of this page please turn Javascript on. Heart Failure What is Heart Failure? In heart failure, the heart cannot pump enough ... failure often experience tiredness and shortness of breath. Heart Failure is Serious Heart failure is a serious and ...

  15. Use of Dexmedetomidine for Prophylactic Analgesia and Sedation in Patients With Delayed Extubation After Craniotomy: A Randomized Controlled Trial

    PubMed Central

    Zhao, Li-Hong; Shi, Zhong-Hua; Chen, Guang-Qiang; Yin, Ning-Ning; Chen, Han; Yuan, Yuan; Cao, Wei; Xu, Ming; Hao, Jing-Jing

    2017-01-01

    Background: We conducted a randomized trial to evaluate the efficacy and safety of dexmedetomidine for prophylactic analgesia and sedation in patients with delayed extubation after craniotomy. Methods: From June 2012 to July 2014, 150 patients with delayed extubation after craniotomy were randomized 1:1 and were assigned to the dexmedetomidine group that received a continuous infusion of 0.6 μg/kg/h (10 μg/mL) or the control group that received a maintenance infusion of 0.9% sodium chloride for injection. The mean percentage of time under optimal sedation (SAS3-4), the percentage of patients who required rescue with propofol/fentanyl, and the total dose of propofol/fentanyl required throughout the course of drug infusion, as well as VAS, HR, MAP, and SpO2 were recorded. Results: The percentage of time under optimal sedation was significantly higher in the dexmedetomidine group than in the control group (98.4%±6.7% vs. 93.0%±16.2%, P=0.008). The VAS was significantly lower in the dexmedetomidine group than in the control group (1.0 vs. 4.0, P=0.000). The HR and mean BP were significantly lower in the dexmedetomidine group than in the control group at all 3 time points (before endotracheal suctioning, immediately after extubation, and 30 min after extubation). No significant difference in SpO2 was observed between the 2 groups. For hemodynamic adverse events, patients in the dexmedetomidine group were more likely to develop bradycardia (5.3% vs. 0%, P=0.043) but had a lower likelihood of tachycardia (2.7% vs. 18.7%, P=0.002). Conclusions: Dexmedetomidine may be an effective prophylactic agent to induce sedation and analgesia in patients with delayed extubation after craniotomy. The use of dexmedetomidine (0.6 μg/kg/h) infusion does not produce respiratory depression, but may increase the incidence of bradycardia. PMID:26641648

  16. Numerical Predictions of Damage and Failure in Carbon Fiber Reinforced Laminates Using a Thermodynamically-Based Work Potential Theory

    NASA Technical Reports Server (NTRS)

    Pineda, Evan Jorge; Waas, Anthony M.

    2013-01-01

    A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, referred to as enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Consistent characteristic lengths are introduced into the formulation to govern the evolution of the failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs are derived. The theory is implemented into a commercial finite element code. The model is verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared against the experimental results.

  17. Revisiting Unplanned Endotracheal Extubation and Disease Severity in Intensive Care Units.

    PubMed

    Chuang, Ming-Lung; Lee, Chai-Yuan; Chen, Yi-Fang; Huang, Shih-Feng; Lin, I-Feng

    2015-01-01

    Most reports regarding unplanned extubation (UE) are case-control studies with matching age and disease severity. To avoid diminishing differences in matched factors, this study with only matching duration of mechanical ventilation aimed to re-examine the risk factors and the factors governing outcomes of UE in intensive care units (ICUs). This case-control study was conducted on 1,775 subjects intubated for mechanical ventilation. Thirty-seven (2.1%) subjects with UE were identified, and 156 non-UE subjects were randomly selected as the control group. Demographic data, acute Physiological and Chronic Health Evaluation II (APACHE II) scores, and outcomes of UE were compared between the two groups. Logistic regression analysis was used to identify the risk factors of UE. Milder disease, younger age, and higher Glasgow Coma Scale (GCS) scores with more frequently being physically restrained (all p<0.05) were related to UE. Logistic regression revealed that APACHE II score (odds ratio (OR) 0.91, p<0.01), respiratory infection (OR 0.24, p<0.01), physical restraint (OR 5.36, p<0.001), and certain specific diseases (OR 3.79-5.62, p<0.05) were related to UE. The UE patients had a lower ICU mortality rate (p<0.01) and a trend of lower in-hospital mortality rate (p = 0.08). Cox regression analysis revealed that in-hospital mortality was associated with APACHE II score, age, shock, and oxygen used, all of which were co-linear, but not UE. The results showed that milder disease with higher GCS scores thereby requiring a higher use of physical restraints were related to UE. Disease severity but not UE was associated with in-hospital mortality.

  18. Effect of bispectral index versus end-tidal anesthetic gas concentration-guided protocol on time to tracheal extubation for halothane-based general anesthesia

    PubMed Central

    Jain, Neena; Mathur, Pooja Rawat; Khan, Shoyeb; Khare, Arvind; Mathur, Veena; Sethi, Surendra

    2016-01-01

    Background and Aims: Early extubation is a desirable goal after general anesthesia. Very few studies have compared the effect of bispectral index (BIS) monitoring versus standard end-tidal anesthetic gas (ETAG) concentration monitoring on tracheal extubation time for halothane-based anesthesia. The aim of this study was to compare the effect of BIS versus ETAG-guided anesthesia on time to tracheal extubation for halothane-based anesthesia in general surgical setting. Methods: This was a randomized, controlled double-blind study. Sixty patients with the American Society of Anesthesiologists physical status Class 1 or 2, receiving halothane-based general anesthesia were randomized to BIS-guided (n = 30) and ETAG-guided anesthesia (n = 30). Time to tracheal extubation was measured. In BIS group, BIS value was kept between 40 and 60 while in ETAG group; ETAG value was kept between 0.7 and 1.3 minimum alveolar concentration. The two groups were compared using Student's t-test, and P < 0.05 was considered statistically significant. Data were processed and analyzed using SPSS version 17 software. Results: Mean time to tracheal extubation was significantly longer in BIS group (9.63 ± 3.02 min) as compared to ETAG group (5.29 ± 1.51 min), mean difference 4.34 min with 95% confidence interval (3.106, 5.982) (P < 0.05). Conclusion: In our study, the extubation time was significantly longer in BIS-guided anesthesia as compared to ETAG-guided anesthesia. ETAG monitoring promotes earlier extubation of patients as compared to BIS monitoring during halothane anesthesia. PMID:27746557

  19. Factors predictive of treatment failure in staphylococcal prosthetic vascular graft infections: a prospective observational cohort study: impact of rifampin

    PubMed Central

    2014-01-01

    Background There exists considerable debate concerning management of prosthetic vascular graft infection (PVGI), especially in terms of antimicrobial treatment. This report studies factors associated with treatment failure in a cohort of patients with staphylococcal PVGI, along with the impact of rifampin (RIF). Methods All data on patients with PVGI between 2006 and 2010 were reviewed. Cure was defined as the absence of evidence of infection during the entire post-treatment follow-up for a minimum of one year. Failure was defined as any other outcome. Results 84 patients (72 M/12 F, median age 64.5 ± 11 y) with diabetes mellitus (n = 25), obesity (n = 48), coronary artery disease (n = 48), renal failure (n = 24) or COPD (n = 22) were treated for PVGI (median follow-up was 470 ± 469 d). PVGI was primarily intracavitary (n = 47). Staphylococcus aureus (n = 65; including 17 methicillin-resistant S. aureus) and coagulase-negative Staphylocococcus (n = 22) were identified. Surgical treatment was performed in 71 patients. In univariate analysis, significant risk factors associated with failure were renal failure (p = 0.04), aortic aneurysm (p = 0.03), fever (p = 0.009), aneurysm disruption (p = 0.02), septic shock in the peri-operative period (p = 0.005) and antibiotic treatment containing RIF (p = 0.03). In multivariate analysis, 2 variables were independently associated with failure:septic shock [OR 4.98: CI 95% 1.45-16.99; p=0.01] and antibiotic containing rifampin [OR: 0.32: CI95% 0.10-0.96; p=0.04]. Conclusion Results of the present study suggest that fever, septic shock and non-use of antibiotic treatment containing RIF are associated with poor outcome. PMID:24775563

  20. Predictive factors of early distant brain failure after gamma knife radiosurgery alone in patients with brain metastases of non-small-cell lung cancer.

    PubMed

    Na, Young Cheol; Jung, Hyun Ho; Kim, Hye Ryun; Cho, Byoung Chul; Chang, Jin Woo; Park, Yong Gou; Chang, Won Seok

    2017-04-01

    The objective of this study was to elucidate the predictive factors for early distant brain failure in patients with brain metastases of non-small-cell lung cancer (NSCLC) who were treated with gamma knife radiosurgery (GKRS) without previous whole-brain radiotherapy (WBRT) or surgery. We retrospectively reviewed clinical and imaging data of 459 patients with brain metastases of NSCLC who underwent GKRS from June 2008 to December 2013. The primary end-point was early distant brain failure, defined as the detection of newly developed metastatic lesions on magnetic resonance imaging (MRI) 3 months after GKRS. Factors such as tumor pathology subtype, concurrent systemic chemotherapy, epidermal growth factor receptor (EGFR) mutation status, use of EGFR tyrosine kinase inhibitors (TKIs), systemic disease status, presence of a metastatic lesion only in delayed MRI, and volume and number of metastases were analyzed. There were no statistically significant differences with respect to pathologic subtype, concurrent systemic chemotherapy, EGFR mutation, and early distant brain failure. Patients treated with EGFR-TKIs (p = 0.004), with a stable systemic disease status (p = 0.028) and 3 or fewer brain lesions (p = 0.000) experienced a significantly lower incidence of early distant brain failure. This study suggests that GKRS alone could be considered for patients treated with EGFR-TKIs who have a stable systemic disease status and 3 or fewer brain lesions. WBRT should be considered for other patients.

  1. Testing failure surface prediction methods and deposit reconstruction for the landslides cluster occurring during Talas Typhoon (Japan)

    NASA Astrophysics Data System (ADS)

    Jaboyedoff, Michel; Chigira, Masahiro; Arai, Noriyuki; Derron, Marc-Henri; Rudaz, Benjamin; Tsou, Ching-Ying

    2016-04-01

    Talas Typhoon hit Japan from 2 to 5 September 2011. It induced more than 70 deep-seated landslides in Kii peninsula. The hi-resolution topography of these landslides have been acquired by aerial 1 m LiDAR digital elevation models (DEM) before (pre-DEM) and after (post-DEM) the events (data from Nara prefectural Government and the Kinki Regional development Bureau of Ministry of Land, Infrastructure, Transportation, and Tourism). This extraordinary opportunity allows us to test methods to construct failure surface geometries, buried valley topographies and/or to rebuild deposits surfaces. We tested the sloping base local level method (SLBL) on 5 deep seated landslides which occurred during Typhoon Talas (Akatani, Kitamata, Nagatono, Shimizu and Akatani-East; see Chigira et al., 2013). The SLBL corresponds to a quadratic surface with a constant second derivative in all x-y directions. This curvature can be based on the knowledge of the length of the landslide and its maximum thickness. We used mainly hillshade DEM, slope maps and Coltop schemes to define the limits of landslides and to interpret their structures. Different attempts were performed to reconstruct the failure surface and deposits depending on a priori knowledge. Basically the morphological features extracted from the pre-DEM were used to delineate the limits of the landslides. The curvature of the failure surface was obtained by "expert" interpretations. The failure surfaces obtained using SLBL are in good agreement with the failure surface observed on the post-DEM. The results are improved when (1) they are adjusted to obtain similar estimate of the volume deduced by Chigira et al. (2013), and when (2) the contours of the landslides used comes from an interpretation of both post and pre-DEM. In order to obtain the expansion coefficient some of these landslide, the missing volume of the deposits (by river erosion) were calculated using inverse SLBL. The coefficient of expansion ranges from 13% to 30

  2. Prediction and Control of Network Cascade: Example of Power Grid or Networking Adaptability from WMD Disruption and Cascading Failures

    SciTech Connect

    Chertkov, Michael

    2012-07-24

    The goal of the DTRA project is to develop a mathematical framework that will provide the fundamental understanding of network survivability, algorithms for detecting/inferring pre-cursors of abnormal network behaviors, and methods for network adaptability and self-healing from cascading failures.

  3. Extended prediction rule to optimise early detection of heart failure in older persons with non-acute shortness of breath: a cross-sectional study

    PubMed Central

    van Riet, Evelien E S; Hoes, Arno W; Limburg, Alexander; Landman, Marcel A J; Kemperman, Hans; Rutten, Frans H

    2016-01-01

    Objectives There is a need for a practical tool to aid general practitioners in early detection of heart failure in the elderly with shortness of breath. In this study, such a screening rule was developed based on an existing rule for detecting heart failure in older persons with a diagnosis of chronic obstructive pulmonary disease. The original rule included a history of ischaemic heart disease, body mass index, laterally displaced apex beat, heart rate, elevated N-terminal pro B-type natriuretic peptide and an abnormal ECG. Design Cross-sectional data were used to validate, update and extend the original prediction rule according to a standardised state-of-the-art stepwise approach. Setting Primary care with 30 participating general practices. Participants Community-dwelling people aged ≥65 years with shortness of breath on exertion. Methods and results Validation of the existing screening rule in our population showed satisfying discrimination with a concordance statistic of 0.84 (range 0.80–0.85), but poor calibration. Performance measures were most improved by adding the predictors age >75 years, peripheral oedema and systolic murmur, resulting in a concordance statistic of 0.88 (range 0.85–0.90) and a net reclassification improvement of 31%. A risk score was computed, which showed high accuracy with a negative predictive value of 87% and a positive predictive value of 73%. Evaluating the improved rule in the derivation set and an independent set of patients with type 2 diabetes aged 60 years or older showed satisfying generalisability of the rule. Conclusions Our rule resulted in excellent prediction of heart failure in the large domain of the elderly with shortness of breath, and would help general practitioners to select those needing echocardiography. Trial registration number NCT01202006. PMID:26880668

  4. Drug Concentration Thresholds Predictive of Therapy Failure and Death in Children With Tuberculosis: Bread Crumb Trails in Random Forests

    PubMed Central

    Swaminathan, Soumya; Pasipanodya, Jotam G.; Ramachandran, Geetha; Hemanth Kumar, A. K.; Srivastava, Shashikant; Deshpande, Devyani; Nuermberger, Eric; Gumbo, Tawanda

    2016-01-01

    Background. The role of drug concentrations in clinical outcomes in children with tuberculosis is unclear. Target concentrations for dose optimization are unknown. Methods. Plasma drug concentrations measured in Indian children with tuberculosis were modeled using compartmental pharmacokinetic analyses. The children were followed until end of therapy to ascertain therapy failure or death. An ensemble of artificial intelligence algorithms, including random forests, was used to identify predictors of clinical outcome from among 30 clinical, laboratory, and pharmacokinetic variables. Results. Among the 143 children with known outcomes, there was high between-child variability of isoniazid, rifampin, and pyrazinamide concentrations: 110 (77%) completed therapy, 24 (17%) failed therapy, and 9 (6%) died. The main predictors of therapy failure or death were a pyrazinamide peak concentration <38.10 mg/L and rifampin peak concentration <3.01 mg/L. The relative risk of these poor outcomes below these peak concentration thresholds was 3.64 (95% confidence interval [CI], 2.28–5.83). Isoniazid had concentration-dependent antagonism with rifampin and pyrazinamide, with an adjusted odds ratio for therapy failure of 3.00 (95% CI, 2.08–4.33) in antagonism concentration range. In regard to death alone as an outcome, the same drug concentrations, plus z scores (indicators of malnutrition), and age <3 years, were highly ranked predictors. In children <3 years old, isoniazid 0- to 24-hour area under the concentration-time curve <11.95 mg/L × hour and/or rifampin peak <3.10 mg/L were the best predictors of therapy failure, with relative risk of 3.43 (95% CI, .99–11.82). Conclusions. We have identified new antibiotic target concentrations, which are potential biomarkers associated with treatment failure and death in children with tuberculosis. PMID:27742636

  5. Usefulness of Cardiac Sympathetic Nerve Imaging Using (123)Iodine-Metaiodobenzylguanidine Scintigraphy for Predicting Sudden Cardiac Death in Patients With Heart Failure.

    PubMed

    Kasama, Shu; Toyama, Takuji; Kurabayashi, Masahiko

    2016-01-01

    The autonomic nervous system plays an important role in the human heart. Activation of the cardiac sympathetic nervous system is a cardinal pathophysiological abnormality associated with the failing human heart. Myocardial imaging using (123)I-metaiodobenzylguanidine (MIBG), an analog of norepinephrine, can be used to investigate the activity of norepinephrine, the predominant neurotransmitter of the sympathetic nervous system. Many clinical trials have demonstrated that (123)I-MIBG scintigraphic parameters predict cardiac adverse events, especially sudden cardiac death, in patients with heart failure. In this review, we summarize results from published studies that have focused on the use of cardiac sympathetic nerve imaging using (123)I-MIBG scintigraphy for risk stratification of sudden cardiac death in patients with heart failure.

  6. PREDICTIVE MODELING OF HOSPITAL READMISSION RATES USING ELECTRONIC MEDICAL RECORD-WIDE MACHINE LEARNING: A CASE-STUDY USING MOUNT SINAI HEART FAILURE COHORT

    PubMed Central

    SHAMEER, KHADER; JOHNSON, KIPP W; YAHI, ALEXANDRE; MIOTTO, RICCARDO; LI, LI; RICKS, DORAN; JEBAKARAN, JEBAKUMAR; KOVATCH, PATRICIA; SENGUPTA, PARTHO P.; GELIJNS, ANNETINE; MOSKOVITZ, ALAN; DARROW, BRUCE; REICH, DAVID L; KASARSKIS, ANDREW; TATONETTI, NICHOLAS P.; PINNEY, SEAN; DUDLEY, JOEL T

    2016-01-01

    Reduction of preventable hospital readmissions that result from chronic or acute conditions like stroke, heart failure, myocardial infarction and pneumonia remains a significant challenge for improving the outcomes and decreasing the cost of healthcare delivery in the United States. Patient readmission rates are relatively high for conditions like heart failure (HF) despite the implementation of high-quality healthcare delivery operation guidelines created by regulatory authorities. Multiple predictive models are currently available to evaluate potential 30-day readmission rates of patients. Most of these models are hypothesis driven and repetitively assess the predictive abilities of the same set of biomarkers as predictive features. In this manuscript, we discuss our attempt to develop a data-driven, electronic-medical record-wide (EMR-wide) feature selection approach and subsequent machine learning to predict readmission probabilities. We have assessed a large repertoire of variables from electronic medical records of heart failure patients in a single center. The cohort included 1,068 patients with 178 patients were readmitted within a 30-day interval (16.66% readmission rate). A total of 4,205 variables were extracted from EMR including diagnosis codes (n=1,763), medications (n=1,028), laboratory measurements (n=846), surgical procedures (n=564) and vital signs (n=4). We designed a multistep modeling strategy using the Naïve Bayes algorithm. In the first step, we created individual models to classify the cases (readmitted) and controls (non-readmitted). In the second step, features contributing to predictive risk from independent models were combined into a composite model using a correlation-based feature selection (CFS) method. All models were trained and tested using a 5-fold cross-validation method, with 70% of the cohort used for training and the remaining 30% for testing. Compared to existing predictive models for HF readmission rates (AUCs in the range

  7. Predictive Factors for the Effect of Treatment by Noninvasive Ventilation in Patients with Respiratory Failure as a Result of Acute Exacerbation of the Chronic Obstructive Pulmonary Disease

    PubMed Central

    Pejkovska, Sava; Kaeva, Biserka Jovkovska; Goseva, Zlatica; Arsovski, Zoran; Janeva, Jelena Jovanovska; Zeynel, Sead

    2015-01-01

    BACKGROUND: Noninvasive mechanical ventilation (NIV) applies ventilator support through the patient’s upper airway using a mask. AIM: The aim of the study is to define factors that will point out an increased risk of NIV failure in patients with exacerbation of Chronic Obstructive Pulmonary Disease (COPD). PATIENTS AND METHODS: Patients over the age of 40, treated with NIV, were prospectively recruited. After data processing, the patients were divided into two groups: 1) successful NIV treatment group; 2) failed NIV treatment group. RESULTS: On admission arterial pH and Glasgow coma scale (GCS) levels were lower (pH: p < 0.05, GCS: p < 0.05), and Acute Physiology and Chronic Health Evaluation II (APACHE) score and PaCO2 were higher (p < 0.05) in the NIV failure group. Arterial pH was lower (p < 0.05) and PaCO2 and respiratory rate were higher (p < 0.05) after 1h, and arterial pH was lower (p < 0.05) and PaCO2 (p < 0.05), respiratory and heart rate were higher (p < 0.05) after 4h in the NIV failure group. CONCLUSION: Measurement and monitoring of certain parameters may be of value in terms of predicting the effectiveness of NIV treatment. PMID:27275303

  8. Donor preoperative oxygen delivery and post-extubation hypoxia impact donation after circulatory death hypoxic cholangiopathy

    PubMed Central

    Chirichella, Thomas J; Dunham, C Michael; Zimmerman, Michael A; Phelan, Elise M; Mandell, M Susan; Conzen, Kendra D; Kelley, Stephen E; Nydam, Trevor L; Bak, Thomas E; Kam, Igal; Wachs, Michael E

    2016-01-01

    .10). HC was independently associated with age, multi-pressor/red-cell transfusion status, arterial oxygen content, hypoxia score, and mean arterial pressure (r2 = 0.6197). The transplantation rate was greater for the later period with more liberal donor selection [era 2 (7.1/year)], compared to our early experience [era 1 (2.5/year)]. HC occurred in 63.0% during era 2 and in 29.4% during era 1 (P = 0.03). Era 2 donors had longer times for extubation-to-asystole (14.4 ± 4.7 m vs 9.3 ± 4.5 m, P = 0.001), ischemia (13.9 ± 5.9 m vs 9.7 ± 5.6 m, P = 0.03), and hypoxemia (16.0 ± 5.1 m vs 11.1 ± 6.7 m, P = 0.013) and a higher hypoxia score > 2.0 rate (73.1% vs 28.6%, P = 0.006). CONCLUSION: Easily measured donor indices, including a hypoxia score, provide an objective measure of DCD liver transplantation risk for recipient HC. Donor selection criteria influence HC rates. PMID:27022221

  9. Deterministic and probabilistic prediction of the distribution of inter-fiber failure test data of prestrained CFRP tubes composed of thin layers and loaded by radial pressure

    SciTech Connect

    Cuntze, R.G.

    1993-12-31

    The limit of usability of a CFRP (Carbon Fiber Reinforced Plastics) structure is often determined by initiation of Inter Fiber Failure (IFF) indicated by interfibre/matrix cracking. It will be shown how this crack initiation threshold can be delayed. The process used is prestraining in analogy to that of prestressed concrete inducing advantageous compression built in stresses/strains transverse to the fibres. As a certain structural example cylindrical tube specimens were wound, prestrained by hydraulic pressurization, and then loaded while monitoring acoustic emission. Crack counting followed the sectioning of the tube. The theoretical investigations aimed at both a deterministic and a probabilistic prediction of the IFF test results. Basis for the prediction are firstly all design parameters, mainly the material properties of the layers, secondly the classical laminate theory and an IFF-criterion and finally a program for probabilistic computations to treat the large set of the stochastic design parameters respectively uncertain basic variables. Included in the IFF-criterion applied had to be the so called Thin-layer Effect representing the decreasing sensitivity of an embedded layer to IFF with the decrease of it`s thickness. The probabilistic prediction of the test data distribution is compared with as well the deterministically predicted single value for the test mean as the corresponding measured test data distribution. They show a very satisfying agreement. The increase in crack-threshold level is shifted from {var_epsilon}{sub hoop} {approx} 0.75% (0% prestrain) to a higher design strain of 1.0% (0.4% prestrain). In case of 0.8% prestrain the design strain even becomes much higher then the operational strain of {approx} 1.15%. This value is normally defined is tensile failure strain e{sub {parallel}}{sup t} {approx} 1.7% in case of T8OO/epoxide composite divided by the usual design factor j{sub u} = 1.5.

  10. The study of homology between tumor progression genes and members of retroviridae as a tool to predict target-directed therapy failure

    PubMed Central

    Fernandes, Janaina

    2015-01-01

    Oncogenes are the primary candidates for target-directed therapy, given that they are involved directly in the progression and resistance of tumors. However, the appearance of point mutations can hinder the treatment of patients with these new molecules, raising costs and the need to development new analogs that target the novel mutations. Based on an analysis of homologies, the present study discusses the possibility of predicting the failure of a protein as a pharmacological target, due to its similarities with retrovirus sequences, which have extremely high mutation rates. This analysis was based on the molecular evidence available in the literature, and widely-used and well-established PSI-BLAST, with two iterations and maximum of 500 aligned sequences. The possibility of predicting which newly-discovered genes involved in tumor progression would likely result in the failure of targeted therapy, using free, simple and automated bioinformatics tools, could provide substantial savings in the time and financial resources needed for long-term drug development. PMID:25983693

  11. Assessment of predictive models for the failure of titanium and ferrous alloys due to hydrogen effects. Report for the period of June 16 to September 15, 1981

    SciTech Connect

    Archbold, T.F.; Bower, R.B.; Polonis, D.H.

    1982-04-01

    The 1977 version of the Simpson-Puls-Dutton model appears to be the most amenable with respect to utilizing known or readily estimated quantities. The Pardee-Paton model requires extensive calculations involving estimated quantities. Recent observations by Koike and Suzuki on vanadium support the general assumption that crack growth in hydride forming metals is determined by the rate of hydride formation, and their hydrogen atmosphere-displacive transformation model is of potential interest in explaining hydrogen embrittlement in ferrous alloys as well as hydride formers. The discontinuous nature of cracking due to hydrogen embrittlement appears to depend very strongly on localized stress intensities, thereby pointing to the role of microstructure in influencing crack initiation, fracture mode and crack path. The initiation of hydrogen induced failures over relatively short periods of time can be characterized with fair reliability using measurements of the threshold stress intensity. The experimental conditions for determining K/sub Th/ and ..delta..K/sub Th/ are designed to ensure plane strain conditions in most cases. Plane strain test conditions may be viewed as a conservative basis for predicting delayed failure. The physical configuration of nuclear waste canisters may involve elastic/plastic conditions rather than a state of plane strain, especially with thin-walled vessels. Under these conditions, alternative predictive tests may be considered, including COD and R-curve methods. The double cantilever beam technique employed by Boyer and Spurr on titanium alloys offers advantages for examining hydrogen induced delayed failure over long periods of time. 88 references. (DLC)

  12. Plasma Apolipoprotein A-V Predicts Long-term Survival in Chronic Hepatitis B Patients with Acute-on-Chronic Liver Failure

    PubMed Central

    Chen, En-Qiang; Wang, Meng-Lan; Zhang, Dong-Mei; Shi, Ying; Wu, Do-Bo; Yan, Li-Bo; Du, Ling-Yao; Zhou, Ling-Yun; Tang, Hong

    2017-01-01

    Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a life-threatening condition, and the lipid metabolism disorder is common in the development of this disease. This prospective observational study aimed to define the characteristics of plasma apolipoprotein A-V (apoA-V) in long-term outcome prediction of HBV-ACLF, and a total of 330 HBV-ACLF patients were included and followed for more than 12 months. In this cohort, the 4-week, 12-week, 24-week and 48-week cumulative mortality of HBV-ACLF was 18.2%(60/330), 50.9%(168/330), 59.7%(197/330) and 63.3%(209/330), respectively. As compared to survivors, the non-survivors had significantly lower concentrations of plasma apoA-V on admission. Plasma apoA-V concentrations were positively correlated with prothrombin time activity (PTA), and negatively correlated with interleukin-10, tumor necrosis factor-α, and iMELD scores. Though plasma apoA-V, PTA, total bilirubin(TBil) and blood urea nitrogen(BUN) were all independent factors to predict one-year outcomes of HBV-ACLF, plasma apoA-V had the highest prediction accuracy. And its optimal cutoff value for one-year survival prediction was 480.00 ng/mL, which had a positive predictive value of 84.68% and a negative predictive value of 92.23%. In summary, plasma apoA-V decreases significantly in non-survivors of HBV-ACLF, and it may be regarded as a new predictive marker for the prognosis of patients with HBV-ACLF. PMID:28358016

  13. Ratio of Systolic Blood Pressure to Right Atrial Pressure, a Novel Marker to Predict Morbidity and Mortality in Acute Systolic Heart Failure.

    PubMed

    Omar, Hesham R; Charnigo, Richard; Guglin, Maya

    2017-04-01

    Congestion is the main contributor to heart failure (HF) morbidity and mortality. We assessed the combined role of congestion and decreased forward flow in predicting morbidity and mortality in acute systolic HF. The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness trial data set was used to determine if the ratio of simultaneously measured systolic blood pressure (SBP)/right atrial pressure (RAP) on admission predicted HF rehospitalization and 6-month mortality. One hundred ninety-five patients (mean age 56.5 years, 75% men) who received pulmonary artery catheterization were studied. The RAP, SBP, and SBP/RAP had an area under the curve (AUC) of 0.593 (p = 0.0205), 0.585 (p = 0.0359), and 0.621 (p = 0.0026), respectively, in predicting HF rehospitalization. The SBP/RAP was a superior marker of HF rehospitalization compared with RAP alone (difference in AUC 0.0289, p = 0.0385). The optimal criterion of SBP/RAP <11 provided the highest combined sensitivity (77.1%) and specificity (50.9%) in predicting HF rehospitalization. The SBP/RAP had an AUC 0.622, p = 0.0108, and a cut-off value of SBP/RAP <8 had a sensitivity of 61.9% and specificity 64.1% in predicting mortality. Multivariate analysis showed that an SBP/RAP <11 independently predicted rehospitalization for HF (estimated odds ratio 3.318, 95% confidence interval 1.692 to 6.506, p = 0.0005) and an SBP/RAP <8 independently predicted mortality (estimated hazard ratio 2.025, 95% confidence interval 1.069 to 3.833, p = 0.030). In conclusion, SBP/RAP ratio is a marker that identifies a spectrum of complications after hospitalization of patients with decompensated systolic HF, starting with increased incidence of HF rehospitalization at SBP/RAP <11 to increased mortality with SBP/RAP <8.

  14. Leukemia-induced phenotypic and functional defects in natural killer cells predict failure to achieve remission in acute myeloid leukemia.

    PubMed

    Stringaris, Kate; Sekine, Takuya; Khoder, Ahmad; Alsuliman, Abdullah; Razzaghi, Bonnie; Sargeant, Ruhena; Pavlu, Jiri; Brisley, Gill; de Lavallade, Hugues; Sarvaria, Anushruthi; Marin, David; Mielke, Stephan; Apperley, Jane F; Shpall, Elizabeth J; Barrett, A John; Rezvani, Katayoun

    2014-05-01

    The majority of patients with acute myeloid leukemia will relapse, and older patients often fail to achieve remission with induction chemotherapy. We explored the possibility that leukemic suppression of innate immunity might contribute to treatment failure. Natural killer cell phenotype and function was measured in 32 consecutive acute myeloid leukemia patients at presentation, including 12 achieving complete remission. Compared to 15 healthy age-matched controls, natural killer cells from acute myeloid leukemia patients were abnormal at presentation, with downregulation of the activating receptor NKp46 (P=0.007) and upregulation of the inhibitory receptor NKG2A (P=0.04). Natural killer cells from acute myeloid leukemia patients had impaired effector function against autologous blasts and K562 targets, with significantly reduced CD107a degranulation, TNF-α and IFN-γ production. Failure to achieve remission was associated with NKG2A overexpression and reduced TNF-α production. These phenotypic and functional abnormalities were partially restored in the 12 patients achieving remission. In vitro co-incubation of acute myeloid leukemia blasts with natural killer cells from healthy donors induced significant impairment in natural killer cell TNF-α and IFN-γ production (P=0.02 and P=0.01, respectively) against K562 targets and a trend to reduced CD107a degranulation (P=0.07). Under transwell conditions, the inhibitory effect of AML blasts on NK cytotoxicity and effector function was still present, and this inhibitory effect was primarily mediated by IL-10. These results suggest that acute myeloid leukemia blasts induce long-lasting changes in natural killer cells, impairing their effector function and reducing the competence of the innate immune system, favoring leukemia survival.

  15. Cephalometric variables predicting the long-term success or failure of combined rapid maxillary expansion and facial mask therapy.

    PubMed

    Baccetti, Tiziano; Franchi, Lorenzo; McNamara, James A

    2004-07-01

    The aim of this study was to select a model of cephalometric variables to predict the results of early treatment of Class III malocclusion with rapid maxillary expansion and facemask therapy followed by comprehensive treatment with fixed appliances. Lateral cephalograms of 42 patients (20 boys, 22 girls) with Class III malocclusion were analyzed at the start of treatment (mean age 8 years 6 months +/- 2 years, at stage I in cervical vertebral maturation). All patients were reevaluated after a mean period of 6 years 6 months (at stage IV or V in cervical vertebral maturation) that included active treatment plus retention. At this time, the sample was divided into 2 groups according to occlusal criteria: a successful group (30 patients) and an unsuccessful group (12 patients). Discriminant analysis was applied to select pretreatment predictive variables of long-term treatment outcome. Stepwise variable selection of the cephalometric measurements at the first observation identified 3 predictive variables. Orthopedic treatment of Class III malocclusion might be unfavorable over the long term when a patient's pretreatment cephalometric records exhibit a long mandibular ramus (ie, increased posterior facial height), an acute cranial base angle, and a steep mandibular plane angle. On the basis of the equation generated by the multivariate statistical method, the outcome of interceptive orthopedic treatment for each new patient with Class III malocclusion can be predicted with a probability error of 16.7%.

  16. Percentage of Biopsy Cores Positive for Malignancy and Biochemical Failure Following Prostate Cancer Radiotherapy in 3,264 Men: Statistical Significance Without Predictive Performance

    SciTech Connect

    Williams, Scott G. Buyyounouski, Mark K.; Pickles, Tom; Kestin, Larry; Martinez, Alvaro; Hanlon, Alexandra L.; Duchesne, Gillian M.

    2008-03-15

    Purpose: To define and incorporate the impact of the percentage of positive biopsy cores (PPC) into a predictive model of prostate cancer radiotherapy biochemical outcome. Methods and Materials: The data of 3264 men with clinically localized prostate cancer treated with external beam radiotherapy at four institutions were retrospectively analyzed. Standard prognostic and treatment factors plus the number of biopsy cores collected and the number positive for malignancy by transrectal ultrasound-guided biopsy were available. The primary endpoint was biochemical failure (bF, Phoenix definition). Multivariate proportional hazards analyses were performed and expressed as a nomogram and the model's predictive ability assessed using the concordance index (c-index). Results: The cohort consisted of 21% low-, 51% intermediate-, and 28% high-risk cancer patients, and 30% had androgen deprivation with radiotherapy. The median PPC was 50% (interquartile range [IQR] 29-67%), and median follow-up was 51 months (IQR 29-71 months). Percentage of positive biopsy cores displayed an independent association with the risk of bF (p = 0.01), as did age, prostate-specific antigen value, Gleason score, clinical stage, androgen deprivation duration, and radiotherapy dose (p < 0.001 for all). Including PPC increased the c-index from 0.72 to 0.73 in the overall model. The influence of PPC varied significantly with radiotherapy dose and clinical stage (p = 0.02 for both interactions), with doses <66 Gy and palpable tumors showing the strongest relationship between PPC and bF. Intermediate-risk patients were poorly discriminated regardless of PPC inclusion (c-index 0.65 for both models). Conclusions: Outcome models incorporating PPC show only minor additional ability to predict biochemical failure beyond those containing standard prognostic factors.

  17. N-terminal pro b-type natriuretic peptide (NT-pro-BNP) –based score can predict in-hospital mortality in patients with heart failure

    PubMed Central

    Huang, Ya-Ting; Tseng, Yuan-Teng; Chu, Tung-Wei; Chen, John; Lai, Min-Yu; Tang, Woung-Ru; Shiao, Chih-Chung

    2016-01-01

    Serum N-terminal pro b-type natriuretic peptide (NT-pro-BNP) testing is recommended in the patients with heart failure (HF). We hypothesized that NT-pro-BNP, in combination with other clinical factors in terms of a novel NT-pro BNP-based score, may provide even better predictive power for in-hospital mortality among patients with HF. A retrospective study enrolled adult patients with hospitalization-requiring HF who fulfilled the predefined criteria during the period from January 2011 to December 2013. We proposed a novel scoring system consisting of several independent predictors including NT-pro-BNP for predicting in-hospital mortality, and then compared the prognosis-predictive power of the novel NT-pro BNP-based score with other prognosis-predictive scores. A total of 269 patients were enrolled in the current study. Factors such as “serum NT-pro-BNP level above 8100 mg/dl,” “age above 79 years,” “without taking angiotensin converting enzyme inhibitors/angiotensin receptor blocker,” “without taking beta-blocker,” “without taking loop diuretics,” “with mechanical ventilator support,” “with non-invasive ventilator support,” “with vasopressors use,” and “experience of cardio-pulmonary resuscitation” were found as independent predictors. A novel NT-pro BNP-based score composed of these risk factors was proposed with excellent predictability for in-hospital mortality. The proposed novel NT-pro BNP-based score was extremely effective in predicting in-hospital mortality in HF patients. PMID:27411951

  18. Factors predictive of the short- and long-term efficacy of growth hormone treatment in prepubertal children with chronic renal failure. The German Study Group for Growth Hormone Treatment in Chronic Renal Failure.

    PubMed

    Haffner, D; Wühl, E; Schaefer, F; Nissel, R; Tönshoff, B; Mehls, O

    1998-10-01

    To evaluate the growth-stimulating effects of short- and long-term treatment with recombinant human growth hormone (rhGH) in growth-retarded children with chronic renal failure (CRF), 103 prepubertal children with CRF on conservative treatment (n = 74) or dialysis (n = 29) were treated with rhGH for up to 5 yr. rhGH treatment persistently increased standardized height (+ 1.6 SD scores) and predicted adult height (+7.7 cm, Tanner method) during the first 3 treatment years (P < 0.001 versus baseline), followed by percentile parallel growth during continued treatment. Both standardized height and predicted adult height were significantly more increased in conservatively treated than in dialyzed children (P < 0.001). Age, GFR, target height, and prestudy growth rate were identified as independent predictors of the response to rhGH treatment during the first and second treatment year. GFR and target height were positively correlated with the change in height SD score and the change in absolute or age-standardized height velocity. Age affected the growth response depending on which outcome measure was used: Although the first-year change in height SD score was inversely correlated with age, the change in absolute height velocity was independent of age, and the change in standardized height velocity was positively correlated with age. The growth response during the first treatment year positively predicted the long-term response. In conclusion, the short- and long-term growth response to rhGH treatment in prepubertal growth-retarded children with CRF is significantly affected by age, GFR, target height, and the pretreatment growth rate. Therefore, rhGH should be preferably started at a young age, and early in the course of CRF.

  19. Markers of beta cell failure predict poor glycemic response to GLP-1 receptor agonist therapy in type 2 diabetes

    PubMed Central

    Jones, Angus G; McDonald, Timothy J; Shields, Beverley M; Hill, Anita V; Hyde, Christopher J; Knight, Bridget A; Hattersley, Andrew T

    2016-01-01

    Objective To assess whether clinical characteristics and simple biomarkers of beta cell failure are associated with individual variation in glycemic response to GLP-1 receptor agonist therapy in patients with type 2 diabetes. Research Design and Methods We prospectively studied 620 participants with type 2 diabetes and HbA1c ≥58mmol/mol (7.5%) commencing GLP-1 receptor agonist therapy as part of their usual diabetes care and assessed response to therapy over 6 months. We assessed the association between baseline clinical measurements associated with beta cell failure and glycemic response (HbA1c change 0 to 6 months, primary outcome) with change in weight (0 to 6 months) as a secondary outcome using linear regression and ANOVA with adjustment for baseline HbA1c and co-treatment change. Results Reduced glycemic response to GLP-1R agonists was associated with longer duration diabetes, insulin co-treatment, lower fasting C-peptide, lower post meal urine C-peptide creatinine ratio and positive GAD or IA2 islet autoantibodies (p≤0.01 for all). Participants with positive autoantibodies or severe insulin deficiency (fasting C-peptide ≤0.25nmol/L) had markedly reduced glycemic response to GLP-1RA therapy (autoantibodies: mean HbA1c change -5.2 vs -15.2 mmol/mol (-0.5 vs -1.4%), p=0.005 C-peptide <0.25nmol/L: mean change -2.1 vs -15.3mmol/mol (-0.2 vs -1.4%), p=0.002). These markers were predominantly present in insulin treated participants and were not associated with weight change. Conclusions Clinical markers of low beta cell function are associated with reduced glycemic response to GLP-1R agonist therapy. C-peptide and islet autoantibodies represent potential biomarkers for the stratification of GLP-1R agonist therapy in insulin treated diabetes. PMID:26242184

  20. Associations Between Prolonged Intubation and Developing Post-extubation Dysphagia and Aspiration Pneumonia in Non-neurologic Critically Ill Patients

    PubMed Central

    Kim, Min Jung; Park, Young Sook; Song, You Hong

    2015-01-01

    Objective To identify the associations between the duration of endotracheal intubation and developing post-extubational supraglottic and infraglottic aspiration (PEA) and subsequent aspiration pneumonia. Methods This was a retrospective observational study from January 2009 to November 2014 of all adult patients who had non-neurologic critical illness, required endotracheal intubation and were referred for videofluoroscopic swallowing study. Demographic information, intensive care unit (ICU) admission diagnosis, severity of critical illness, duration of endotracheal intubation, length of stay in ICU, presence of PEA and severity of dysphagia were reviewed. Results Seventy-four patients were enrolled and their PEA frequency was 59%. Patients with PEA had significantly longer endotracheal intubation durations than did those without (median [interquartile range]: 15 [9-21] vs. 10 [6-15] days; p=0.02). In multivariate logistic regression analysis, the endotracheal intubation duration was significantly associated with PEA (odds ratio, 1.09; 95% confidence interval [CI], 1.01-1.18; p=0.04). Spearman correlation analysis of intubation duration and dysphagia severity showed a positive linear association (r=0.282, p=0.02). The areas under the receiver operating characteristic curves (AUCs) of endotracheal intubation duration for developing PEA and aspiration pneumonia were 0.665 (95% CI, 0.542-0.788; p=0.02) and 0.727 (95% CI, 0.614-0.840; p=0.001), respectively. Conclusion In non-neurologic critically ill patients, the duration of endotracheal intubation was independently associated with PEA development. Additionally, the duration was positively correlated with dysphagia severity and may be helpful for identifying patients who require a swallowing evaluation after extubation. PMID:26605174

  1. Generalized energy failure criterion.

    PubMed

    Qu, R T; Zhang, Z J; Zhang, P; Liu, Z Q; Zhang, Z F

    2016-03-21

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the "generalized energy criterion", as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components.

  2. Generalized energy failure criterion

    PubMed Central

    Qu, R. T.; Zhang, Z. J.; Zhang, P.; Liu, Z. Q.; Zhang, Z. F.

    2016-01-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the “generalized energy criterion”, as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components. PMID:26996781

  3. Minimizing the cost of translocation failure with decision-tree models that predict species' behavioral response in translocation sites.

    PubMed

    Ebrahimi, Mehregan; Ebrahimie, Esmaeil; Bull, C Michael

    2015-08-01

    The high number of failures is one reason why translocation is often not recommended. Considering how behavior changes during translocations may improve translocation success. To derive decision-tree models for species' translocation, we used data on the short-term responses of an endangered Australian skink in 5 simulated translocations with different release conditions. We used 4 different decision-tree algorithms (decision tree, decision-tree parallel, decision stump, and random forest) with 4 different criteria (gain ratio, information gain, gini index, and accuracy) to investigate how environmental and behavioral parameters may affect the success of a translocation. We assumed behavioral changes that increased dispersal away from a release site would reduce translocation success. The trees became more complex when we included all behavioral parameters as attributes, but these trees yielded more detailed information about why and how dispersal occurred. According to these complex trees, there were positive associations between some behavioral parameters, such as fight and dispersal, that showed there was a higher chance, for example, of dispersal among lizards that fought than among those that did not fight. Decision trees based on parameters related to release conditions were easier to understand and could be used by managers to make translocation decisions under different circumstances.

  4. On colloid retention in saturated porous media in the presence of energy barriers: The failure of α, and opportunities to predict η

    NASA Astrophysics Data System (ADS)

    Johnson, William P.; Tong, Meiping; Li, Xiqing

    2007-12-01

    This contribution reviews recent findings that illuminate the processes governing colloid retention in porous media under environmentally relevant conditions. In the environment, colloids act as conveyors of contaminants, or even as contaminants themselves; however, despite decades of research, we are unable to accurately predict the retention of colloids in granular aquifer media under environmental conditions, where repulsion exists between colloids and surfaces. This failure cannot be blamed solely on the complexities of the subsurface, since colloid filtration theory (CFT) works well in the absence of colloid-collector repulsion despite its idealization of porous media as consisting of spherical grains completely surrounded by fluid envelopes. Rather, the failure of CFT stems from failure to incorporate the correct mechanisms of retention when repulsion exists. Recent observations implicate wedging in grain-to-grain contacts and retention in secondary energy minima as dominant mechanisms of colloid retention in the presence of an energy barrier. Mechanistic simulations in unit cells containing grain-to-grain contacts corroborate these mechanisms of colloid retention. The resulting concept for colloid retention in the presence of an energy barrier involves translation of colloids across the collector surfaces until they become wedged within grain-to-grain contacts, or are retained via secondary energy minima (without attachment) in zones where the balance of fluid drag, diffusion, gravitational, and colloid-collector interaction forces allow retention. The above findings highlight the pore domain geometry as a dominant governor of colloid retention in so far as the geometry gives rise to grain-to-grain contacts and zones of relatively low fluid drag.

  5. Usefulness of early diastolic mitral annular velocity to predict plasma levels of brain natriuretic peptide and transient heart failure development after device closure of atrial septal defect.

    PubMed

    Masutani, Satoshi; Taketazu, Mio; Mihara, Chihiro; Mimura, Yuko; Ishido, Hirotaka; Matsunaga, Tamotsu; Kobayashi, Toshiki; Senzaki, Hideaki

    2009-12-15

    Device closure of atrial septal defect (ASD) is sometimes followed by elevation of plasma brain natriuretic peptide (BNP), a marker of heart failure, and progression to heart failure. This study tested the hypothesis that the underlying diastolic dysfunction, assessed on tissue Doppler images (TDI) before device closure, can predict BNP level after ASD closure. The study subjects were 39 consecutive patients (age 27.5 +/- 16.3 years, range 5 to 63) who underwent device closure for ASD. Echocardiographic evaluation using TDI and 2-dimensional and pulse wave Doppler were performed, together with plasma BNP measurement 1 day before and 2 days after ASD closure. Before ASD closure, an age-dependent decrease was noted in left ventricular relaxation, assessed by early diastolic mitral annular velocity. ASD closure resulted in a decrease in early diastolic mitral annular velocity (from 14.7 to 12.3 cm/s, p <0.05) despite an increase in the left ventricular dimension (84% to 92% vs normal, p <0.05). These changes were associated with a parallel increase in BNP (17.9 to 48.4 pg/ml, p <0.05). Stepwise multivariate linear regression identified early diastolic mitral annular velocity before ASD closure and age as independent predictors of BNP levels after ASD closure (p <0.05). Consistent with this result, 2 patients with the lowest early diastolic mitral annular velocity developed exertional dyspnea after the procedure. In conclusion, our results indicate that TDI measurements could be useful to detect underlying diastolic dysfunction that can potentially cause heart failure after ASD closure and emphasize the importance of ASD closure at a young age before impairment of left ventricular relaxation.

  6. The clustering-based case-based reasoning for imbalanced business failure prediction: a hybrid approach through integrating unsupervised process with supervised process

    NASA Astrophysics Data System (ADS)

    Li, Hui; Yu, Jun-Ling; Yu, Le-An; Sun, Jie

    2014-05-01

    Case-based reasoning (CBR) is one of the main forecasting methods in business forecasting, which performs well in prediction and holds the ability of giving explanations for the results. In business failure prediction (BFP), the number of failed enterprises is relatively small, compared with the number of non-failed ones. However, the loss is huge when an enterprise fails. Therefore, it is necessary to develop methods (trained on imbalanced samples) which forecast well for this small proportion of failed enterprises and performs accurately on total accuracy meanwhile. Commonly used methods constructed on the assumption of balanced samples do not perform well in predicting minority samples on imbalanced samples consisting of the minority/failed enterprises and the majority/non-failed ones. This article develops a new method called clustering-based CBR (CBCBR), which integrates clustering analysis, an unsupervised process, with CBR, a supervised process, to enhance the efficiency of retrieving information from both minority and majority in CBR. In CBCBR, various case classes are firstly generated through hierarchical clustering inside stored experienced cases, and class centres are calculated out by integrating cases information in the same clustered class. When predicting the label of a target case, its nearest clustered case class is firstly retrieved by ranking similarities between the target case and each clustered case class centre. Then, nearest neighbours of the target case in the determined clustered case class are retrieved. Finally, labels of the nearest experienced cases are used in prediction. In the empirical experiment with two imbalanced samples from China, the performance of CBCBR was compared with the classical CBR, a support vector machine, a logistic regression and a multi-variant discriminate analysis. The results show that compared with the other four methods, CBCBR performed significantly better in terms of sensitivity for identifying the

  7. Early Indication of Decompensated Heart Failure in Patients on Home-Telemonitoring: A Comparison of Prediction Algorithms Based on Daily Weight and Noninvasive Transthoracic Bio-impedance

    PubMed Central

    Bonomi, Alberto G; Goode, Kevin M; Reiter, Harald; Habetha, Joerg; Amft, Oliver; Cleland, John GF

    2016-01-01

    Background Heart Failure (HF) is a common reason for hospitalization. Admissions might be prevented by early detection of and intervention for decompensation. Conventionally, changes in weight, a possible measure of fluid accumulation, have been used to detect deterioration. Transthoracic impedance may be a more sensitive and accurate measure of fluid accumulation. Objective In this study, we review previously proposed predictive algorithms using body weight and noninvasive transthoracic bio-impedance (NITTI) to predict HF decompensations. Methods We monitored 91 patients with chronic HF for an average of 10 months using a weight scale and a wearable bio-impedance vest. Three algorithms were tested using either simple rule-of-thumb differences (RoT), moving averages (MACD), or cumulative sums (CUSUM). Results Algorithms using NITTI in the 2 weeks preceding decompensation predicted events (P<.001); however, using weight alone did not. Cross-validation showed that NITTI improved sensitivity of all algorithms tested and that trend algorithms provided the best performance for either measurement (Weight-MACD: 33%, NITTI-CUSUM: 60%) in contrast to the simpler rules-of-thumb (Weight-RoT: 20%, NITTI-RoT: 33%) as proposed in HF guidelines. Conclusions NITTI measurements decrease before decompensations, and combined with trend algorithms, improve the detection of HF decompensation over current guideline rules; however, many alerts are not associated with clinically overt decompensation. PMID:26892844

  8. Plasma neutrophil gelatinase-associated lipocalin as a marker for the prediction of worsening renal function in children hospitalized for acute heart failure.

    PubMed

    Elsharawy, Sahar; Raslan, Lila; Morsy, Saed; Hassan, Basheir; Khalifa, Naglaa

    2016-01-01

    Acute heart failure (AHF) is frequently associated with worsening renal function in adult patients. Neutrophil gelatinase-associated lipocalin (NGAL) serves as an early marker for acute renal tubular injury. To assess the role of plasma NGAL in predicting worsening renal function (WRF) in children with AHF, we studied 30 children hospitalized for AHF; children with history of chronic renal disease or on nephrotoxic drugs were excluded. Twenty age- and sex-matched healthy children were included in the study as a control group. Echocardiographic examination was performed on admission. Blood urea nitrogen (BUN), serum creatinine, estimated glomerular filtration rate (eGFR) and plasma NGAL levels were measured on admission and 72 h later. Seventeen (56.6%) patients developed WRF within the three-day follow-up period. At presentation, plasma NGAL level was significantly elevated in children who developed WRF. Admission plasma NGAL level correlated with renal parameters (BUN, creatinine and eGFR) as well as with left ventricular systolic parameters (ejection fraction and fractional shortening). For prediction of WRF, admission plasma, NGAL level>27.5 μg/L had sensitivity and specificity of 90% and 68%, respectively. The area under the receiver-operator curve was higher for NGAL (0.869) than for BUN (0.569) or eGFR (0.684). We conclude that admission plasma NGAL level can predict WRF in children hospitalized for AHF.

  9. Fatigue life prediction using multiaxial energy calculations with the mean stress effect to predict failure of linear and nonlinear elastic solids

    NASA Astrophysics Data System (ADS)

    Nagode, Marko; Šeruga, Domen

    An approach is presented that enables the calculation of elastic strain energy in linear and nonlinear elastic solids during arbitrary thermomechanical load cycles. The approach uses the simple fact that the variation of both strain and complementary energies always forms a rectangular shape in stress-strain space, hence integration is no longer required to calculate the energy. Furthermore, the approach considers the mean stress effect so that predictions of fatigue damage are more realistically representative of real-life experimental observations. By doing so, a parameter has been proposed to adjust the mean stress effect. This parameter α is based on the well-known Smith-Watson-Topper energy criterion, but allows consideration of other arbitrary mean stress effects, e.g. the Bergmann type criterion. The approach has then been incorporated into a numerical method which can be applied to uniaxial and multiaxial, proportional and non-proportional loadings to predict fatigue damage. The end result of the method is the cyclic evolution of accumulated damage. Numerical examples show how the method presented in this paper could be applied to a nonlinear elastic material.

  10. Predictive value of plasma copeptin level for the risk and mortality of heart failure: a meta-analysis.

    PubMed

    Yan, Jian-Jun; Lu, Ying; Kuai, Zheng-Ping; Yong, Yong-Hong

    2017-02-28

    Epidemiologic studies are inconsistent regarding the association between plasma copeptin level and heart failure (HF). The aim of this study was to perform a meta-analysis to determine whether high level of copeptin is correlated with incidence of HF and mortality in patients with HF. We searched PUBMED and EMBASE databases for studies conducted from 1966 through May 2016 to identify studies reporting hazard ratio (HR) estimates with 95% confidence intervals (CIs) for the association between plasma copeptin level and HF. A random-effects model was used to combine study-specific risk estimates. A total of 13 studies were included in the meta-analysis, with five studies on the incidence of HF and eight studies on the mortality of patients with HF. For incidence of HF, the summary HR indicated a borderline positive association of high plasma copeptin level with HF risk (HR, 1.60; 95% CI, 0.90-2.85). Furthermore, an increase of 1 standard deviation in log copeptin level was associated with a 17% increase in the risk of incident HF (HR, 1.17; 95% CI, 1.02-1.33). For all-cause mortality of patients with HF, we also found a significant association between elevated plasma copeptin level and increased mortality of HF (HR, 1.76; 95% CI, 1.33-2.33). Our dose-response analysis indicated that an increment in copeptin level of 1 pmol/l was associated with a 3% increase in all-cause mortality (HR, 1.03; 95% CI, 1.01-1.05). In conclusion, our results suggest that elevated plasma copeptin level is associated with an increased risk of HF and all-cause mortality in patients with HF.

  11. Non-linear Equation using Plasma Brain Natriuretic Peptide Levels to Predict Cardiovascular Outcomes in Patients with Heart Failure

    PubMed Central

    Fukuda, Hiroki; Suwa, Hideaki; Nakano, Atsushi; Sakamoto, Mari; Imazu, Miki; Hasegawa, Takuya; Takahama, Hiroyuki; Amaki, Makoto; Kanzaki, Hideaki; Anzai, Toshihisa; Mochizuki, Naoki; Ishii, Akira; Asanuma, Hiroshi; Asakura, Masanori; Washio, Takashi; Kitakaze, Masafumi

    2016-01-01

    Brain natriuretic peptide (BNP) is the most effective predictor of outcomes in chronic heart failure (CHF). This study sought to determine the qualitative relationship between the BNP levels at discharge and on the day of cardiovascular events in CHF patients. We devised a mathematical probabilistic model between the BNP levels at discharge (y) and on the day (t) of cardiovascular events after discharge for 113 CHF patients (Protocol I). We then prospectively evaluated this model on another set of 60 CHF patients who were readmitted (Protocol II). P(t|y) was the probability of cardiovascular events occurring after >t, the probability on t was given as p(t|y) = −dP(t|y)/dt, and p(t|y) = pP(t|y) = αyβP(t|y), along with p = αyβ (α and β were constant); the solution was p(t|y) = αyβ exp(−αyβt). We fitted this equation to the data set of Protocol I using the maximum likelihood principle, and we obtained the model p(t|y) = 0.000485y0.24788 exp(−0.000485y0.24788t). The cardiovascular event-free rate was computed as P(t) = 1/60Σi=1,…,60 exp(−0.000485yi0.24788t), based on this model and the BNP levels yi in a data set of Protocol II. We confirmed no difference between this model-based result and the actual event-free rate. In conclusion, the BNP levels showed a non-linear relationship with the day of occurrence of cardiovascular events in CHF patients. PMID:27845390

  12. Non-linear Equation using Plasma Brain Natriuretic Peptide Levels to Predict Cardiovascular Outcomes in Patients with Heart Failure

    NASA Astrophysics Data System (ADS)

    Fukuda, Hiroki; Suwa, Hideaki; Nakano, Atsushi; Sakamoto, Mari; Imazu, Miki; Hasegawa, Takuya; Takahama, Hiroyuki; Amaki, Makoto; Kanzaki, Hideaki; Anzai, Toshihisa; Mochizuki, Naoki; Ishii, Akira; Asanuma, Hiroshi; Asakura, Masanori; Washio, Takashi; Kitakaze, Masafumi

    2016-11-01

    Brain natriuretic peptide (BNP) is the most effective predictor of outcomes in chronic heart failure (CHF). This study sought to determine the qualitative relationship between the BNP levels at discharge and on the day of cardiovascular events in CHF patients. We devised a mathematical probabilistic model between the BNP levels at discharge (y) and on the day (t) of cardiovascular events after discharge for 113 CHF patients (Protocol I). We then prospectively evaluated this model on another set of 60 CHF patients who were readmitted (Protocol II). P(t|y) was the probability of cardiovascular events occurring after >t, the probability on t was given as p(t|y) = ‑dP(t|y)/dt, and p(t|y) = pP(t|y) = αyβP(t|y), along with p = αyβ (α and β were constant); the solution was p(t|y) = αyβ exp(‑αyβt). We fitted this equation to the data set of Protocol I using the maximum likelihood principle, and we obtained the model p(t|y) = 0.000485y0.24788 exp(‑0.000485y0.24788t). The cardiovascular event-free rate was computed as P(t) = 1/60Σi=1,…,60 exp(‑0.000485yi0.24788t), based on this model and the BNP levels yi in a data set of Protocol II. We confirmed no difference between this model-based result and the actual event-free rate. In conclusion, the BNP levels showed a non-linear relationship with the day of occurrence of cardiovascular events in CHF patients.

  13. Asymptomatic Left Bundle Branch Block Predicts New-Onset Congestive Heart Failure and Death From Cardiovascular Diseases

    PubMed Central

    Azadani, Peyman N.; Soleimanirahbar, Ata; Marcus, Gregory M.; Haight, Thaddeus J.; Hollenberg, Milton; Olgin, Jeffrey E.; Lee, Byron K.

    2012-01-01

    Background Left bundle branch block (LBBB) has been proposed as a risk factor for cardiovascular morbidity and mortality. We sought to characterize the strength of these associations in a population without preexisting clinical heart disease. Methods The association between LBBB and new-onset congestive heart failure (CHF) or death from cardiovascular diseases was examined in 1,688 participants enrolled in the SPPARCS study who were free of known CHF or previous myocardial infarction. SPPARCS is a community-based cohort study in residents of Sonoma, California that are > 55 years. Medical history and 12-lead ECGs were obtained every 2 years for up to 6 years of follow-up. LBBB at enrollment or year 2 was considered “baseline” and assessed as a predictor of CHF and cardiovascular death ascertained at years 4 and 6. Results The prevalence of LBBB at baseline was 2.5% (n = 42). During 6 years of follow-up, 70 (4.8%) people developed new CHF. Incidence of CHF was higher in patients with LBBB than in participants without LBBB. This association persisted after controlling for potential confounders (odds ratio (OR): 2.85; 95% confidence interval (CI): 1.01 - 8.02; P = 0.047). A higher mortality from cardiovascular diseases was also found in participants with LBBB after adjusting for potential confounders (OR: 2.35, 95%CI: 1.02 - 5.41; P = 0.044). Conclusions LBBB in the absence of a clinically detectable heart disease is associated with new-onset CHF and death from cardiovascular diseases. Further study is warranted to determine if additional diagnostic testing or earlier treatment in patients with asymptomatic LBBB can decrease cardiovascular morbidity or mortality.

  14. Intrathoracic impedance vs daily weight monitoring for predicting worsening heart failure events: results of the Fluid Accumulation Status Trial (FAST).

    PubMed

    Abraham, William T; Compton, Steven; Haas, Garrie; Foreman, Blair; Canby, Robert C; Fishel, Robert; McRae, Scott; Toledo, Gloria B; Sarkar, Shantanu; Hettrick, Douglas A

    2011-01-01

    The relative sensitivity and unexplained detection rate of changes in intrathoracic impedance has not been compared with standard heart failure (HF) monitoring using daily weight changes. The Fluid Accumulation Status Trial (FAST) prospectively followed 156 HF patients with implanted cardioverter-defibrillator or cardiac resynchronization therapy defibrillator devices modified to record daily changes in intrathoracic impedance in a blinded fashion for 537±312 days. Daily impedance changes were used to calculate a fluid index that could be compared with a prespecified threshold. True positives were defined as adjudicated episodes of worsening HF occurring within 30 days of a fluid index above threshold or an acute weight gain. Unexplained detections were defined as threshold crossings or acute weight gains not associated with worsening HF. Impedance measurements were performed on >99% of follow-up days, compared with only 76% of days for weight measurements. Sixty-five HF events occurred during follow-up (0.32/patient-year). Forty HF events were detected by impedance but not weight, whereas 5 were detected by weight but not impedance. Sensitivity was greater (76% vs 23%; P<.0001) and unexplained detection rate was lower (1.9 vs 4.3/patient-year; P<.0001) for intrathoracic impedance monitoring at the threshold of 60Ω days compared with acute weight increases of 3 lbs in 1 day or 5 lbs in 3 days and also over a wide range of fluid index and weight thresholds. The sensitivity and unexplained detection rate of intrathoracic impedance monitoring was superior to that seen for acute weight changes. Intrathoracic impedance monitoring represents a useful adjunctive clinical tool for managing HF in patients with implanted devices.

  15. Use of Proton-Pump Inhibitors Predicts Heart Failure and Death in Patients with Coronary Artery Disease

    PubMed Central

    Pello Lázaro, Ana María; Cristóbal, Carmen; Franco-Peláez, Juan Antonio; Tarín, Nieves; Aceña, Álvaro; Carda, Rocío; Huelmos, Ana; Martín-Mariscal, María Luisa; Fuentes-Antras, Jesús; Martínez-Millá, Juan; Alonso, Joaquín; Lorenzo, Óscar; Egido, Jesús; López-Bescós, Lorenzo; Tuñón, José

    2017-01-01

    Objectives Proton-pump inhibitors (PPIs) seem to increase the incidence of cardiovascular events in patients with coronary artery disease (CAD), mainly in those using clopidogrel. We analysed the impact of PPIs on the prognosis of patients with stable CAD. Methods We followed 706 patients with CAD. Primary outcome was the combination of secondary outcomes. Secondary outcomes were 1) acute ischaemic events (any acute coronary syndrome, stroke, or transient ischaemic attack) and 2) heart failure (HF) or death. Results Patients on PPIs were older [62.0 (53.0–73.0) vs. 58.0 (50.0–70.0) years; p = 0.003] and had a more frequent history of stroke (4.9% vs. 1.1%; p = 0.004) than those from the non-PPI group, and presented no differences in any other clinical variable, including cardiovascular risk factors, ejection fraction, and therapy with aspirin and clopidogrel. Follow-up was 2.2±0.99 years. Seventy-eight patients met the primary outcome, 53 developed acute ischaemic events, and 33 HF or death. PPI use was an independent predictor of the primary outcome [hazard ratio (HR) = 2.281 (1.244–4.183); p = 0.008], along with hypertension, body-mass index, glomerular filtration rate, atrial fibrillation, and nitrate use. PPI use was also an independent predictor of HF/death [HR = 5.713 (1.628–20.043); p = 0.007], but not of acute ischaemic events. A propensity score showed similar results. Conclusions In patients with CAD, PPI use is independently associated with an increased incidence of HF and death but not with a high rate of acute ischaemic events. Further studies are needed to confirm these findings. PMID:28103324

  16. A micromechanical model to predict damage and failure in biological tissues. Application to the ligament-to-bone attachment in the human knee joint.

    PubMed

    Subit, D; Chabrand, P; Masson, C

    2009-02-09

    Computational models are developed in injury biomechanics to assess lesions in biological tissues based on mechanical measurements. The linear mechanics of fracture theory (LMFT) is a common approach to establish injuries based on thresholds (such as force or strain thresholds) which are straightforward to implement and computationally efficient. However, LMFT does not apply to non-linear heterogeneous materials and does not have the ability to predict failure onset. This paper proposes the cohesive zone model theory (CZMT) as an alternative. CZMT focuses on the development of behaviour laws for crack initiation and propagation at an interface that apply within a fibrous material or at the interface between materials. With the view of evaluating CZMT for biological tissues, the model developed by Raous et al. [1999. A consistent model coupling adhesion, friction and unilateral contact. Comput. Methods Appl. Mech. Eng., 177, 383-399] was applied to the ligament-to-bone interface in the human knee joint. This model accounts for adhesion, friction and damage at the interface and provides a smooth transition from total adhesion to complete failure through the intensity of adhesion variable. A 2D finite element model was developed to mimic previous experiments, and the model parameters were determined using a dichotomy method. The model showed good results by its ability to predict damage. The extension to a 3D geometry, with an inverse problem approach, is, however, required to better estimate the model parameters values. Although it is computationally costly, CZMT supplements the improvements achieved in microimaging techniques to support the development of micro/macro approaches in biomechanical modelling.

  17. Usefulness of two-dimensional echocardiographic parameters of the left side of the heart to predict right ventricular failure after left ventricular assist device implantation.

    PubMed

    Kato, Tomoko Sugiyama; Farr, Maryjane; Schulze, Paul Christian; Maurer, Mathew; Shahzad, Khurram; Iwata, Shinichi; Homma, Shunichi; Jorde, Ulrich; Takayama, Hiroo; Naka, Yoshifumi; Gillam, Linda; Mancini, Donna

    2012-01-15

    Right ventricular failure (RVF) after left ventricular assist device (LVAD) placement is associated with increased morbidity and mortality. Echocardiography is a primary imaging method in the assessment of cardiac function; however, visualization of the right-sided heart is often technically difficult in patients with heart failure. We aimed to create a simple and generally applicable scoring system based on "left-sided echocardiographic parameters" to provide complementary information for predicting RVF after LVAD surgery. We reviewed 111 consecutive patients undergoing LVAD surgery from 2007 through 2010. Echocardiograms within 5 days before surgery were analyzed. RVF was defined as an unexpected RV assist devices requirement, nitric oxide inhalation >48 hours, and/or inotropic support >14 days. Thirty-five patients (32%) developed RVF. LV end-diastolic dimension (LVEDD) was smaller, LV ejection fraction was greater, and the left atrial diameter/LVEDD ratio was greater (p < 0.05 for all comparisons) in patients with RVF than in those without RVF. An RVF score (LV echocardiographic RVF score) was determined as a sum of points based on receiver operator characteristics analysis: LVEDD >78, 79 to 70, and <70 mm; LV ejection fraction ≤19%, 19% to 33%, and >33%; and left atrial diameter/LVEDD <0.63, 0.63 to 0.68, and >0.68; each variable was associated with 0 and 1 point and 2 points, respectively. LV echocardiographic RVF score ≥3 was associated with RVF with a sensitivity of 88.6% and score ≥5 with a specificity of 80.3%. In conclusion, patients with relatively small LV size, preserved LV contraction, and dilated left atrium were at higher risk for RVF after LVAD surgery. In conclusion, LV echocardiographic RVF score provides a novel tool to predict RVF after LVAD surgery, which does not involve invasive or technically complicated procedures.

  18. WAIS-IV Digit Span variables: are they valuable for use in predicting TOMM and MSVT failure?

    PubMed

    Whitney, Kriscinda A; Shepard, Polly H; Davis, Jeremy J

    2013-01-01

    The Digit Span (DS) task in the Wechsler Adult Intelligence Scale-Fourth Edition differs substantially from earlier versions of the measure, with one of the major changes being the addition of a sequencing component. In the present investigation, the usefulness of the new sequencing task and other DS variables (i.e., DS Age-Scaled Score, DS Forward Total, DS Backward Total, and Reliable DS) was investigated with regard to the ability of these variables to predict negative response bias. Negative response bias was first defined and examined using below-cutoff performance on the Test of Memory Malingering (TOMM) (N = 99). Then, for comparison purposes, negative response bias was examined using below-cutoff performance on the Medical Symptom Validity Test (MSVT; N = 95). Study participants included primarily middle-aged outpatients at a Veterans Affairs medical center. Findings from this retrospective analysis showed that, regardless of whether the TOMM or the MSVT was used as the negative response bias criterion, of all the DS variables examined, DS Sequencing Total showed the best classification accuracy. Yet, due to its relatively low positive and negative predictive power, DS Sequencing Total is not recommended for use in isolation to identify negative response bias.

  19. A validated model for the prediction of rotor bar failure in squirrel-cage motors using instantaneous angular speed

    NASA Astrophysics Data System (ADS)

    Sasi, Ahmed Y. Ben; Gu, Fengshou; Li, Yuhua; Ball, Andrew D.

    2006-10-01

    Instantaneous angular speed (IAS)-based condition monitoring is an area in which significant progress has been achieved over the recent years. This condition monitoring technique is less known compared to the existing conventional methods. This paper presents model-predicted simulation and experimental results of broken rotor bar faults in a three-phase induction motor using IAS variations. The simulation was performed under normal, and a broken rotor bar fault. The present paper evaluates through simulating and measuring the IAS of an induction motor at broken rotor bar faults in both time and frequency domains. Experimental results show a good agreement with the model-predicted simulation results. Three vital key features were extracted from the angular speed variations. One feature is the modulating contour of pole pass frequency periods in time domain. The other two features are in frequency domain. The primary feature is the presence of the pole pass frequency component at the low-frequency region of the IAS spectrum. The secondary feature which are the multiple of pole pass frequency sideband components around the rotor speed frequency component. Experimental results confirm the validity of the simulation results for the proposed method. The IAS has demonstrated more sensitivity than current signature analysis in detecting the fault. This research also shows the power of angular speed features as a useful tool to detect broken rotor bar deteriorations using any economical transducer such as low-resolution rotary shaft encoders; which may well be already installed for process control purposes.

  20. Neural Network Prediction of Failure of Damaged Composite Pressure Vessels from Strain Field Data Acquired by a Computer Vision Method

    NASA Technical Reports Server (NTRS)

    Russell, Samuel S.; Lansing, Matthew D.

    1997-01-01

    This effort used a new and novel method of acquiring strains called Sub-pixel Digital Video Image Correlation (SDVIC) on impact damaged Kevlar/epoxy filament wound pressure vessels during a proof test. To predict the burst pressure, the hoop strain field distribution around the impact location from three vessels was used to train a neural network. The network was then tested on additional pressure vessels. Several variations on the network were tried. The best results were obtained using a single hidden layer. SDVIC is a fill-field non-contact computer vision technique which provides in-plane deformation and strain data over a load differential. This method was used to determine hoop and axial displacements, hoop and axial linear strains, the in-plane shear strains and rotations in the regions surrounding impact sites in filament wound pressure vessels (FWPV) during proof loading by internal pressurization. The relationship between these deformation measurement values and the remaining life of the pressure vessels, however, requires a complex theoretical model or numerical simulation. Both of these techniques are time consuming and complicated. Previous results using neural network methods had been successful in predicting the burst pressure for graphite/epoxy pressure vessels based upon acoustic emission (AE) measurements in similar tests. The neural network associates the character of the AE amplitude distribution, which depends upon the extent of impact damage, with the burst pressure. Similarly, higher amounts of impact damage are theorized to cause a higher amount of strain concentration in the damage effected zone at a given pressure and result in lower burst pressures. This relationship suggests that a neural network might be able to find an empirical relationship between the SDVIC strain field data and the burst pressure, analogous to the AE method, with greater speed and simplicity than theoretical or finite element modeling. The process of testing SDVIC

  1. PBSC mobilization in lymphoma patients: analysis of risk factors for collection failure and development of a predictive score based on the kinetics of circulating CD34+ cells and WBC after chemotherapy and G-CSF mobilization.

    PubMed

    Rossi, Giuseppe; Skert, Cristina; Morello, Enrico; Almici, Camillo; Arcaini, Luca; Basilico, Claudia; Cavalli, Lara; Botto, Barbara; Castelli, Andrea; Pica, Gianmatteo; Ripamonti, Francesco; Salvi, Flavia; Carella, Angelo M; Gaidano, Gianluca; Levis, Alessandro; Nosari, Annamaria; Russo, Domenico; Vitolo, Umberto

    2015-09-01

    Autologous stem cell transplantation (ASCT) is a potentially curative treatment of lymphoma, but peripheral blood stem cell (PBSC) mobilization fails in some patients. PBSC mobilizing agents have recently been proved to improve the PBSC yield after a prior mobilization failure. Predictive parameters of mobilization failure allowing for a preemptive, more cost-effective use of such agents during the first mobilization attempt are still poorly defined, particularly during mobilization with chemotherapy + granulocyte colony-stimulating factor (G-CSF). We performed a retrospective analysis of a series of lymphoma patients who were candidates for ASCT, to identify factors influencing PBSC mobilization outcome. Premobilization parameters-age, histology, disease status, mobilizing protocol, and previous treatments-as well as white blood cell (WBC) and PBSC kinetics, markers potentially able to predict failure during the ongoing mobilization attempt, were analyzed in 415 consecutive mobilization procedures in 388 patients. We used chemotherapy + G-CSF in 411 (99%) of mobilization attempts and PBSC collection failed (<2 × 10(6) CD34+ PBSC/kg) in 13%. Multivariable analysis showed that only a low CD34+ PBSC count and CD34+ PBSC/WBC ratio, together with the use of nonplatinum-containing chemotherapy, independently predicted mobilization failure. Using these three parameters, we established a scoring system to predict risk of failure during mobilization ranging from 2 to 90%, thus allowing a selective use of a preemptive mobilization policy.

  2. Low expression of CXCR1/2 on neutrophils predicts poor survival in patients with hepatitis B virus-related acute-on-chronic liver failure

    PubMed Central

    Xu, Ruonan; Bao, Chunmei; Huang, Huihuang; Lin, Fang; Yuan, Yue; Wang, Siyu; Jin, Lei; Yang, Tao; Shi, Ming; Zhang, Zheng; Wang, Fu-Sheng

    2016-01-01

    Polymorphonuclear neutrophils (PMNs) and proinflammatory cytokines have been implicated in the pathogenesis of acute-on-chronic liver failure (ACLF). But the utility of CXC chemokine receptor expression on PMNs as a biomarker for prediction of disease severity is still uncertain. In this study, we investigated the dynamic expression of CXCR1 and CXCR2 on neutrophils, and found that patients with hepatitis B virus-related ACLF displayed low expression of CXCR1 and CXCR2 on peripheral neutrophils compared with healthy subjects and patients with chronic hepatitis B. This expression pattern was correlated with disease severity. Additionally, increased production of IL-8 in peripheral blood was significantly associated with reduced CXCR1 and CXCR2 expression, as shown by the decreased CXCR1 and CXCR2 expression on neutrophils after treating neutrophils with plasma from ACLF patients. This effect could be overcomed through IL-8 blockage with an anti-IL-8 antibody. We also found that IL-8 production and neutrophil infiltration were coordinately increased in the liver tissue of HBV-ACLF patients, and this increase was associated with liver inflammation. Overall, increased production of IL-8 associated with neutrophils infiltration into the liver and decreased CXCR1/2 expression on peripheral neutrophils. CXCR1 and CXCR2 expression levels could be served as early markers to predict the severity of ACLF. PMID:27974825

  3. A predictive analytics approach to reducing 30-day avoidable readmissions among patients with heart failure, acute myocardial infarction, pneumonia, or COPD.

    PubMed

    Shams, Issac; Ajorlou, Saeede; Yang, Kai

    2015-03-01

    Hospital readmission has become a critical metric of quality and cost of healthcare. Medicare anticipates that nearly $17 billion is paid out on the 20 % of patients who are readmitted within 30 days of discharge. Although several interventions such as transition care management have been practiced in recent years, the effectiveness and sustainability depends on how well they can identify patients at high risk of rehospitalization. Based on the literature, most current risk prediction models fail to reach an acceptable accuracy level; none of them considers patient's history of readmission and impacts of patient attribute changes over time; and they often do not discriminate between planned and unnecessary readmissions. Tackling such drawbacks, we develop a new readmission metric based on administrative data that can identify potentially avoidable readmissions from all other types of readmission. We further propose a tree-based classification method to estimate the predicted probability of readmission that can directly incorporate patient's history of readmission and risk factors changes over time. The proposed methods are validated with 2011-12 Veterans Health Administration data from inpatients hospitalized for heart failure, acute myocardial infarction, pneumonia, or chronic obstructive pulmonary disease in the State of Michigan. Results shows improved discrimination power compared to the literature (c-statistics >80 %) and good calibration.

  4. Comparison of Proposed Modified and Original Sequential Organ Failure Assessment Scores in Predicting ICU Mortality: A Prospective, Observational, Follow-Up Study

    PubMed Central

    Gholipour Baradari, Afshin; Daneshiyan, Maryam; Aarabi, Mohsen; Talebiyan Kiakolaye, Yaser; Nouraei, Seyed Mahmood; Zamani Kiasari, Alieh; Habibi, Mohammad Reza; Emami Zeydi, Amir; Sadeghi, Faegheh

    2016-01-01

    Background. The sequential organ failure assessment (SOFA) score has been recommended to triage critically ill patients in the intensive care unit (ICU). This study aimed to compare the performance of our proposed MSOFA and original SOFA scores in predicting ICU mortality. Methods. This prospective observational study was conducted on 250 patients admitted to the ICU. Both tools scores were calculated at the beginning, 24 hours of ICU admission, and 48 hours of ICU admission. Diagnostic odds ratio and receiver operating characteristic (ROC) curve were used to compare the two scores. Results. MSOFA and SOFA predicted mortality similarly with an area under the ROC curve of 0.837, 0.992, and 0.977 for MSOFA 1, MSOFA 2, and MSOFA 3, respectively, and 0.857, 0.988, and 0.988 for SOFA 1, SOFA 2, and SOFA 3, respectively. The sensitivity and specificity of MSOFA 1 in cut-off point 8 were 82.9% and 68.4%, respectively, MSOFA 2 in cut-off point 9.5 were 94.7% and 97.1%, respectively, and MSOFA 3 in cut-off point of 9.3 were 97.4% and 93.1%, respectively. There was a significant positive correlation between the MSOFA 1 and the SOFA 1 (r: 0.942), 24 hours (r: 0.972), and 48 hours (r: 0.960). Conclusion. The proposed MSOFA and the SOFA scores had high diagnostic accuracy, sensitivity, and specificity for predicting mortality. PMID:28116220

  5. Usefulness of Combining Galectin-3 and BIVA Assessments in Predicting Short- and Long-Term Events in Patients Admitted for Acute Heart Failure

    PubMed Central

    De Berardinis, Benedetta; Magrini, Laura; Zampini, Giorgio; Zancla, Benedetta; Salerno, Gerardo; Cardelli, Patrizia; Di Stasio, Enrico; Gaggin, Hanna K.; Belcher, Arianna; Parry, Blair A.; Nagurney, John T.; Januzzi, James L.; Di Somma, Salvatore

    2014-01-01

    Introduction. Acute heart failure (AHF) is associated with a higher risk for the occurrence of rehospitalization and death. Galectin-3 (GAL3) is elevated in AHF patients and is an indicator in predicting short-term mortality. The total body water using bioimpedance vector analysis (BIVA) is able to identify mortality within AHF patients. The aim of this study was to evaluate the short- and long-term predictive value of GAL3, BIVA, and the combination of both in AHF patients in Emergency Department (ED). Methods. 205 ED patients with AHF were evaluated by testing for B type natriuretic peptide (BNP) and GAL3. The primary endpoint was death and rehospitalization at 30, 60, 90, and 180 days and 12 and 18 months. AHF patients were evaluated at the moment of ED arrival with clinical judgment and GAL3 and BIVA measurement. Results. GAL3 level was significantly higher in patients >71 years old, and with eGFR < 30 cc/min. The area under the curve (AUC) of GAL3 + BIVA, GAL3 and BIVA for death and rehospitalization both when considered in total and when considered serially for the follow-up period showed that the combination has a better prognostic value. Kaplan-Meier survival curve for GAL3 values >17.8 ng/mL shows significant survival difference. At multivariate Cox regression analysis GAL3 is an independent variable to predict death + rehospitalization with a value of 32.24 ng/mL at 30 days (P < 0.005). Conclusion. In patients admitted for AHF an early assessment of GAL3 and BIVA seems to be useful in identifying patients at high risk for death and rehospitalization at short and long term. Combining the biomarker and the device could be of great utility since they monitor the severity of two pathophysiological different mechanisms: heart fibrosis and fluid overload. PMID:25101304

  6. Improvement in Health-Related Quality of Life After Hospitalization Predicts Event-free Survival in Patients with Advanced Heart Failure

    PubMed Central

    Moser, Debra K.; Yamokoski, Laura; Sun, Jie Lena; Conway, Ginger A.; Hartman, Karen A.; Graziano, Judith A.; Grant, Jane; Sun, Jie-Lena; Binanay, Cynthia; Stevenson, Lynne W.

    2009-01-01

    Background Health-related quality of life (HRQOL) is a major clinical outcome for heart failure (HF) patients. We aimed to determine the frequency, durability, and prognostic significance of improved HRQOL after hospitalization for decompensated HF. Methods and Results We analyzed HRQOL, measured serially using the Minnesota Living with Heart Failure Questionnaire (MLHFQ), for 425 patients who survived to discharge in a multicenter randomized clinical trial of pulmonary artery catheter versus clinical assessment to guide therapy for patients with advanced HF. All patients enrolled had one or more prior HF hospitalizations or chronic high diuretic doses and one or more symptom and one sign of fluid overload at admission. Improvement, defined as a decrease of more than 5 points in MLHFQ total score, occurred in 68% of patients by 1 month and stabilized. The degree of 1 month improvement differed (P<0.0001 group × time interaction) between 6 month survivors and non-survivors. In a Cox regression model, after adjustment for traditional risk factors for HF morbidity and mortality, improvement in HRQOL by 1 month compared to worsening at one month or no change predicted time to subsequent event-free survival (P=0.013). Conclusions In patients hospitalized with severe HF decompensation, HRQOL is seriously impaired but improves substantially within 1 month for most patients and remains improved for 6 months. Patients for whom HRQOL does not improve by 1 month after hospital admission merit specific attention both to improve HRQOL and to address high risk for poor event-free survival. PMID:19879462

  7. Interval to Biochemical Failure Predicts Clinical Outcomes in Patients With High-Risk Prostate Cancer Treated by Combined-Modality Radiation Therapy

    SciTech Connect

    Shilkrut, Mark; McLaughlin, P. William; Merrick, Gregory S.; Vainshtein, Jeffrey M.; Feng, Felix Y.; Hamstra, Daniel A.

    2013-07-15

    Purpose: To validate the prognostic value of interval to biochemical failure (IBF) in patients with high-risk prostate cancer (HiRPCa) treated with combined-modality radiation therapy (CMRT) with or without androgen deprivation therapy (ADT). Methods and Materials: We conducted a retrospective review of HiRPCa (prostate-specific antigen >20 ng/mL, Gleason score [GS] 8-10, or clinical T stage T3-T4) treated with either dose-escalated external beam radiation therapy (EBRT) or CMRT. Interval to biochemical failure was classified as ≤18 or >18 months from the end of all therapy to the date of biochemical failure (BF). Kaplan-Meier methods and Cox proportional hazards regression were used to evaluate the prognostic value of IBF ≤18 months for distant metastasis (DM) and prostate cancer-specific mortality (PCSM). Results: Of 958 patients with a median follow-up of 63.2 months, 175 patients experienced BF. In those with BF, there were no differences in pretreatment clinical characteristics between the EBRT and CMRT groups, except for a higher proportion of patients with GS 8-10 in the CMRT group (70% vs 52%, P=.02). Median IBF after all therapy was 24.0 months (interquartile range 9.6-46.0) in the EBRT group and 18.9 months (interquartile range 9.2-34.5) in the CMRT group (P=.055). On univariate analysis, IBF ≤18 months was associated with increased risk of DM and PCSM in the entire cohort and the individual EBRT and CMRT groups. On multivariate analysis, only GS 9-10 and IBF ≤18 months, but not the radiation therapy regimen or ADT use, predicted DM (hazard ratio [HR] 3.7, P<.01, 95% confidence interval [CI] 1.4-10.3 for GS 9-10; HR 3.9, P<.0001, 95% CI 2.4-6.5 for IBF ≤18 months) and PCSM (HR 14.8, P<.009, 95% CI 2.0-110 for GS 9-10; HR 4.4, P<.0001, 95% CI 2.4-8.1 for IBF ≤18 months). Conclusions: Short IBF was highly prognostic for higher DM and PCSM in patients with HiRPCa. The prognostic value of IBF for DM and PCSM was not affected by the radiation

  8. The Therapeutic Outcomes of Mechanical Ventilation in Hematological Malignancy Patients with Respiratory Failure.

    PubMed

    Fujiwara, Yusuke; Yamaguchi, Hiroki; Kobayashi, Katsuya; Marumo, Atsushi; Omori, Ikuko; Yamanaka, Satoshi; Yui, Shunsuke; Fukunaga, Keiko; Ryotokuji, Takeshi; Hirakawa, Tsuneaki; Okabe, Masahiro; Wakita, Satoshi; Tamai, Hayato; Okamoto, Muneo; Nakayama, Kazutaka; Takeda, Shinhiro; Inokuchi, Koiti

    2016-01-01

    Objective In hematological malignancy patients, the complication of acute respiratory failure often reaches a degree of severity that necessitates mechanical ventilation. The objective of the present study was to investigate the therapeutic outcomes of mechanical ventilation in hematological malignancy patients with respiratory failure and to analyze the factors that are associated with successful treatment in order to identify the issues that should be addressed in the future. Methods The present study was a retrospective analysis of 71 hematological malignancy patients with non-cardiogenic acute respiratory failure who were treated with mechanical ventilation at Nippon Medical School Hospital between 2003 and 2014. Results Twenty-six patients (36.6%) were treated with mechanical ventilation in an intensive care unit (ICU). Non-invasive positive pressure ventilation (NPPV) was applied in 29 cases (40.8%). The rate of successful mechanical ventilation treatment with NPPV alone was 13.8%. The rate of endotracheal extubation was 17.7%. A univariate analysis revealed that the following factors were associated with the successful extubation of patients who received invasive mechanical ventilation: respiratory management in an ICU (p=0.012); remission of the hematological disease (p=0.011); female gender (p=0.048); low levels of accompanying non-respiratory organ failure (p=0.041); and the non-use of extracorporeal circulation (p=0.005). A subsequent multivariate analysis revealed that respiratory management in an ICU was the only variable associated with successful extubation (p=0.030). Conclusion The outcomes of hematological malignancy patients who receive mechanical ventilation treatment for respiratory failure are very poor. Respiratory management in an ICU environment may be useful in improving the therapeutic outcomes of such patients.

  9. A Brief Review of Non-invasive Monitoring of Respiratory Condition for Extubated Patients with or at Risk for Obstructive Sleep Apnea after Surgery.

    PubMed

    Zhang, Xuezheng; Kassem, Mahmoud Attia Mohamed; Zhou, Ying; Shabsigh, Muhammad; Wang, Quanguang; Xu, Xuzhong

    2017-01-01

    Obstructive sleep apnea (OSA) is one of the important risk factors contributing to postoperative airway complications. OSA alters the respiratory physiology and increases the sensitivity of muscle tone of the upper airway after surgery to residual anesthetic medication. In addition, the prevalence of OSA was reported to be much higher among surgical patients than the general population. Therefore, appropriate monitoring to detect early respiratory impairment in postoperative extubated patients with possible OSA is challenging. Based on the comprehensive clinical observation, several equipment have been used for monitoring the respiratory conditions of OSA patients after surgery, including the continuous pulse oximetry, capnography, photoplethysmography (PPG), and respiratory volume monitor (RVM). To date, there has been no consensus on the most suitable device as a recommended standard of care. In this review, we describe the advantages and disadvantages of some possible monitoring strategies under certain clinical conditions. According to the literature, the continuous pulse oximetry, with its high sensitivity, is still the most widely used device. It is also cost-effective and convenient to use but has low specificity and does not reflect ventilation. Capnography is the most widely used device for detection of hypoventilation, but it may not provide reliable data for extubated patients. Even normal capnography cannot exclude the existence of hypoxia. PPG shows the state of both ventilation and oxygenation, but its sensitivity needs further improvement. RVM provides real-time detection of hypoventilation, quantitative precise demonstration of respiratory rate, tidal volume, and MV for extubated patients, but no reflection of oxygenation. Altogether, the sole use of any of these devices is not ideal for monitoring of extubated patients with or at risk for OSA after surgery. However, we expect that the combined use of continuous pulse oximetry and RVM may be

  10. Effects of Lignocaine Administered Intravenously or Intratracheally on Airway and Hemodynamic Responses during Emergence and Extubation in Patients Undergoing Elective Craniotomies in Supine Position

    PubMed Central

    Shabnum, Tabasum; Ali, Zulfiqar; Naqash, Imtiaz Ahmad; Mir, Aabid Hussain; Azhar, Khan; Zahoor, Syed Amer; Mir, Abdul Waheed

    2017-01-01

    Introduction: Sympathoadrenergic responses during emergence and extubation can lead to an increase in heart rate (HR) and blood pressure whereas increased airway responses may lead to coughing and laryngospasm. The aim of our study was to compare the effects of lignocaine administered intravenously (IV) or intratracheally on airway and hemodynamic responses during emergence and extubation in patients undergoing elective craniotomies. Methodology: Sixty patients with physical status American Society of Anaesthesiologists Classes I and II aged 18–70 years, scheduled to undergo elective craniotomies were included. The patients were randomly divided into three groups of twenty patients; Group 1 receiving IV lignocaine and intratracheal placebo (IV group), Group 2 receiving intratracheal lignocaine and IV placebo (I/T group), and Group 3 receiving IV and intratracheal placebo (placebo group). The tolerance to the endotracheal tube was monitored, and number of episodes of cough was recorded during emergence and at the time of extubation. Hemodynamic parameters such as HR and blood pressure (systolic, diastolic, mean arterial pressure) were also recorded. Results: There was a decrease of HR in both IV and intratracheal groups in comparison with placebo group (P < 0.005). Rise in blood pressure (systolic blood pressure, diastolic blood pressure and mean arterial pressure) was comparable in both Groups 1 and 2 but was lower in comparison with placebo group (P < 0.005). Cough suppression was comparable in all the three groups. Grade III cough (15%) was documented only in placebo group. Conclusion: Both IV and intratracheal lignocaine are effective in attenuation of hemodynamic response if given within 20 min from skull pin removal to extubation. There was comparable cough suppression through intratracheal route and IV routes than the placebo group. PMID:28298788

  11. A Brief Review of Non-invasive Monitoring of Respiratory Condition for Extubated Patients with or at Risk for Obstructive Sleep Apnea after Surgery

    PubMed Central

    Zhang, Xuezheng; Kassem, Mahmoud Attia Mohamed; Zhou, Ying; Shabsigh, Muhammad; Wang, Quanguang; Xu, Xuzhong

    2017-01-01

    Obstructive sleep apnea (OSA) is one of the important risk factors contributing to postoperative airway complications. OSA alters the respiratory physiology and increases the sensitivity of muscle tone of the upper airway after surgery to residual anesthetic medication. In addition, the prevalence of OSA was reported to be much higher among surgical patients than the general population. Therefore, appropriate monitoring to detect early respiratory impairment in postoperative extubated patients with possible OSA is challenging. Based on the comprehensive clinical observation, several equipment have been used for monitoring the respiratory conditions of OSA patients after surgery, including the continuous pulse oximetry, capnography, photoplethysmography (PPG), and respiratory volume monitor (RVM). To date, there has been no consensus on the most suitable device as a recommended standard of care. In this review, we describe the advantages and disadvantages of some possible monitoring strategies under certain clinical conditions. According to the literature, the continuous pulse oximetry, with its high sensitivity, is still the most widely used device. It is also cost-effective and convenient to use but has low specificity and does not reflect ventilation. Capnography is the most widely used device for detection of hypoventilation, but it may not provide reliable data for extubated patients. Even normal capnography cannot exclude the existence of hypoxia. PPG shows the state of both ventilation and oxygenation, but its sensitivity needs further improvement. RVM provides real-time detection of hypoventilation, quantitative precise demonstration of respiratory rate, tidal volume, and MV for extubated patients, but no reflection of oxygenation. Altogether, the sole use of any of these devices is not ideal for monitoring of extubated patients with or at risk for OSA after surgery. However, we expect that the combined use of continuous pulse oximetry and RVM may be

  12. Serial measurement of NT-proBNP predicts adverse cardiovascular outcome in children with primary myocardial dysfunction and acute decompensated heart failure (ADHF)

    PubMed Central

    Medar, Shivanand; Hsu, Daphne T.; Ushay, H. Michael; Lamour, Jacqueline M.; Cohen, Hillel W; Killinger, James S.

    2015-01-01

    Introduction In children, elevated amino terminal pro B-type naturetic peptide (NT-proBNP) levels are associated with impaired heart function. The predictive value of serial monitoring of NT-proBNP levels in acute decompensated heart failure (ADHF) is unclear. Methods This prospective observational study enrolled patients ≤ 21 years with primary myocardial dysfunction and ADHF. NT-proBNP levels were obtained on enrollment (D0), day 2 (D2) and day 7 (D7). Clinical, laboratory and imaging data were collected on enrollment. CV outcome was defined as Heart Transplant (HTx), Ventricular Assist Device (VAD) placement, Extracorporeal Membrane Oxygenation or death at 1 year after admission. NT-proBNP levels and the percent change from D0 to D2 and D0 to D7 were calculated and compared between those with and without adverse cardiovascular (ACV) outcome. Results Sixteen consecutive patients were enrolled. ACV outcome occurred in 6 (37.5%, 4 HTx and 2 VAD). In patients with an ACV outcome, median NT-ProBNP levels at D7 were significantly higher (7,365 Vs. 1,196 pg/ml; p= 0.02) and the percent decline in NT-proBNP was significantly smaller (28% vs. 73%, p=0.02) compared to those without an ACV outcome. ROC curve analysis revealed that a less than 55% decline in NT-proBNP levels at D7 had a sensitivity and specificity of 83% and 90% respectively in predicting an ACV [AUC 0.86, CI (0.68,1.0), p=0.02]. Conclusions In conclusion, children with primary myocardial dysfunction and ADHF, a persistently elevated NT-proBNP and/or a lesser degree of decline in NT-proBNP during the first week of presentation were strongly associated with ACV outcome. Serial NT-proBNP monitoring may allow the early identification of children at risk for worse outcome. PMID:25856472

  13. Left Atrial Function Predicts Heart Failure Hospitalization in Subjects with Preserved Ejection Fraction and Coronary Heart Disease: Longitudinal Data from the Heart and Soul Study

    PubMed Central

    Welles, Christine C.; Ku, Ivy A.; Kwan, Damon M.; Whooley, Mary A.; Schiller, Nelson B.; Turakhia, Mintu P.

    2012-01-01

    Objectives We sought to determine whether left atrial (LA) dysfunction predicts heart failure (HF) hospitalization in subjects with preserved baseline ejection fraction (EF). Background Among patients with preserved EF, factors leading to HF are not fully understood. Cross-sectional studies have demonstrated LA dysfunction at the time of HF, but longitudinal data on antecedent atrial function are lacking. Methods We performed resting transthoracic echocardiography in 855 subjects with coronary heart disease and EF≥50%. Left atrial functional index (LAFI) was calculated as [(LA emptying fraction × left ventricular outflow tract-velocity time integral)/(indexed LA end systolic volume)], where LA emptying fraction was defined as (LA end systolic volume - LA end diastolic volume)/LA end systolic volume. We used Cox models to evaluate the association between LAFI and HF hospitalization. Results Over a median follow-up of 7.9 years, 106 participants (12.4%) were hospitalized for HF. Rates of HF hospitalization were inversely proportional to quartile of LAFI: Q1: 47 per 1000 person-years; Q2: 18.3; Q3: 9.6; and Q4: 5.3 (p<0.001). Each standard deviation decrease in LAFI was associated with a 2.6-fold increased hazard of adverse cardiovascular outcomes (unadjusted HR: 2.6, 95% CI 2.1–3.3, p<0.001), and the association persisted even after adjustment for clinical risk factors, NT-proBNP, and a wide range of echocardiographic parameters (adjusted HR: 1.5, 95% CI 1.0–2.1, p=0.05). Conclusions LA dysfunction independently predicts HF hospitalization in subjects with coronary heart disease and preserved baseline EF. LAFI may be useful for HF risk stratification, and LA dysfunction may be a potential therapeutic target. PMID:22322084

  14. Contribution of the long-term care insurance certificate for predicting 1-year all-cause readmission compared with validated risk scores in elderly patients with heart failure

    PubMed Central

    Takahashi, Kayo; Saito, Makoto; Inaba, Shinji; Morofuji, Toru; Aisu, Hiroe; Sumimoto, Takumi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Higaki, Jitsuo

    2016-01-01

    Objectives Readmission is a common and serious problem associated with heart failure (HF). Unfortunately, conventional risk models have limited predictive value for predicting readmission. The recipients of long-term care insurance (LTCI) are frail and have mental and physical impairments. We hypothesised that adjustment of the conventional risk score with an LTCI certificate enables a more accurate appreciation of readmission for HF. Methods We investigated 452 patients with HF who were followed up for 1 year to determine all-cause readmission. We obtained their clinical and socioeconomic data, including LTCI. The three clinical risk scores used in our evaluation were Keenan (2008), Krumholz (2000) and Charlson (1994). We used net reclassification improvement (NRI) to assess the incremental benefit. Results Patients with LTCI were significantly older, and had a higher prevalence of cerebrovascular disease and dementia than those without LTCI. One-year all-cause readmission (n=193, 43%) was significantly associated with all risk scores, receiving LTCI and the category of LTCI. Receiving LTCI was associated with readmission independent of all risk scores (HR, 1.59 to 1.63; all p<0.01). Adding LTCI to all risk scores led to a significantly improved reclassification, which was observed in the subgroup of patients with HF with preserved ejection fraction (≥50%) but not in the subgroup with reduced ejection fraction (<50%). Conclusions Possession of an LTCI certificate was independently associated with 1-year all-cause readmission after adjusting for validated clinical risk scores in patients with HF. Adding LTCI status significantly improved the model performance for readmission risk, particularly in patients with HF and preserved ejection fraction. PMID:27933194

  15. Respiratory Failure

    MedlinePlus

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  16. Heart Failure

    MedlinePlus

    Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Heart failure does not mean that your heart has stopped ... Tiredness and shortness of breath Common causes of heart failure are coronary artery disease, high blood pressure and ...

  17. Hybrid Microcircuit Failure Rate Prediction

    DTIC Science & Technology

    1978-04-01

    drawn. The problem with the metal platform package was a thermal mismatch between the metal package and the glass seal around the leads and was limited to...made generalizations for broad classifications of package types virtually impossible. Package seal perimeter, however, was found to be a significant...parameter for all types of packages. The new package term is a function of only the seal perimeter, temperature, and environment. f. The substrate

  18. The Usefulness of the Delta Neutrophil Index for Predicting Superimposed Pneumonia in Patients with Acute Decompensated Heart Failure in the Emergency Department

    PubMed Central

    Lee, Jong Wook; Kwon, Woocheol; Lee, Seok Jeong; Kang, Kyung Sik; Kim, Hyung Il; Kim, Oh Hyun; Cha, Kyoung-Chul; Kim, Hyun; Hwang, Sung Oh

    2016-01-01

    Background Although respiratory infections, such as pneumonia, have long been recognized as precipitators of exacerbation in patients with acute decompensated heart failure (ADHF), identifying signs of concomitant pneumonia in ADHF is a clinical diagnostic challenge. We evaluated the predictive value of the delta neutrophil index (DNI), a new indicator for immature granulocytes, for diagnosing superimposed pneumonia in patients presenting with ADHF in the emergency department (ED). Methods This was a retrospective and observational study of consecutive patients (>18 years old) diagnosed with an ADHF in the ED over a 7-month period. Patients were categorized into either the ADHF group or the ADHF with pneumonia group. DNI, serum white blood cell (WBC), C-reactive protein (CRP), and β-natriuretic peptide (BNP) were measured upon ED arrival. Results The ADHF with pneumonia group included 30 patients (20.4%). Median initial DNI, WBC, and CRP were significantly higher in the ADHF with pneumonia group [0% vs. 1.8%, p<0.001, 8,200 cells/mL vs. 10,470 cells/mL, p<0.001, and 0.56 mg/dL vs. 6.10 mg/dL, p<0.001]. Multiple logistic regression analyses showed that only initial DNI significantly predicted the presence of superimposed pneumonia in patients with ADHF. In the receiver operating characteristic curves for initial DNI, WBC, and CRP for differentiating superimposed pneumonia in ADHF patients, the area under curve (AUC) of DNI (0.916 [95% confidence interval 0.859–0.955]) was good. AUC of DNI was significantly higher than AUC of CRP and WBC [0.828 and 0.715] (DNI vs. CRP, p = 0.047 and DNI vs. WBC, p<0.001). Conclusions Initial DNI, which was measured upon ED arrival, was significantly higher in the ADHF with pneumonia group than in the ADHF group. The initial DNI’s ability of prediction for ADHF with superimposed pneumonia in the ED was good and it was better than those of serum WBC and CRP. Therefore, DNI may serve as a convenient and useful marker for early

  19. Establishment and Validation of ALPH-Q Score to Predict Mortality Risk in Patients With Acute-on-Chronic Hepatitis B Liver Failure

    PubMed Central

    Wu, Sheng-Jie; Yan, Hua-Dong; Zheng, Zai-Xing; Shi, Ke-Qing; Wu, Fa-Ling; Xie, Yao-Yao; Fan, Yu-Chen; Ye, Bo-Zhi; Huang, Wei-Jian; Chen, Yong-Ping; Zheng, Ming-Hua

    2015-01-01

    Abstract Currently, there are no robust models for predicting the outcome of acute-on-chronic hepatitis B liver failure (ACHBLF). We aimed to establish and validate a new prognostic scoring system, named ALPH-Q, that integrates electrocardiography parameters that may be used to predict short-term mortality of patients with ACHBLF. Two hundred fourteen patients were included in this study. The APLH-Q score was constructed by Cox proportional hazard regression analysis and was validated in an independent patient cohort. The area under the receiver-operating characteristic curve was used to compare the performance of different models, including APLH-Q, Child–Pugh score (CPS), model of end-stage liver disease (MELD), and a previously reported logistic regression model (LRM). The APLH-Q score was constructed with 5 independent risk factors, including age (HR = 1.034, 95% CI: 1.007–1.061), liver cirrhosis (HR = 2.753, 95% CI: 1.366–5.548), prothrombin time (HR = 1.031, 95% CI: 1.002–1.062), hepatic encephalopathy (HR = 2.703, 95% CI: 1.630–4.480), and QTc (HR = 1.008, 95% CI: 1.001–1.016). The performance of the ALPH-Q score was significantly better than that of MELD and CPS in both the training (0.896 vs 0.712, 0.896 vs 0.738, respectively, both P < 0.05) and validation cohorts (0.837 vs 0.689, 0.837 vs 0.585, respectively, both P < 0.05). Compared with LRM, APLH-Q also showed a better performance (0.896 vs 0.825, 0.837 vs 0.818, respectively). We have developed a novel APLH-Q score with greater performance than CPS, MELD, and LRM for predicting short-term mortality of patients with ACHBLF. PMID:25590846

  20. In-hospital percentage BNP reduction is highly predictive for adverse events in patients admitted for acute heart failure: the Italian RED Study

    PubMed Central

    2010-01-01

    Introduction Our aim was to evaluate the role of B-type natriuretic peptide (BNP) percentage variations at 24 hours and at discharge compared to its value at admission in order to demonstrate its predictive value for outcomes in patients with acute decompensated heart failure (ADHF). Methods This was a multicenter Italian (8 centers) observational study (Italian Research Emergency Department: RED). 287 patients with ADHF were studied through physical exams, lab tests, chest X Ray, electrocardiograms (ECGs) and BNP measurements, performed at admission, at 24 hours, and at discharge. Follow up was performed 180 days after hospital discharge. Logistic regression analysis was used to estimate odds ratios (OR) for the various subgroups created. For all comparisons, a P value < 0.05 was considered statistically significant. Results BNP median (interquartile range (IQR)) value at admission was 822 (412 - 1390) pg\\mL; at 24 hours was 593 (270 - 1953) and at discharge was 325 (160 - 725). A BNP reduction of >46% at discharge had an area under curve (AUC) of 0.70 (P < 0.001) for predicting future adverse events. There were 78 events through follow up and in 58 of these patients the BNP level at discharge was >300 pg/mL. A BNP reduction of 25.9% after 24 hours had an AUC at ROC curve of 0.64 for predicting adverse events (P < 0.001). The odds ratio of the patients whose BNP level at discharge was <300 pg/mL and whose percentage decrease at discharge was <46% compared to the group whose BNP level at discharge was <300 pg/mL and whose percentage decrease at discharge was >46% was 4.775 (95% confidence interval (CI) 1.76 - 12.83, P < 0.002). The odds ratio of the patients whose BNP level at discharge was >300 pg/mL and whose percentage decrease at discharge was <46% compared to the group whose BNP level at discharge was <300 pg/mL and whose percentage decrease at discharge was >46% was 9.614 (CI 4.51 - 20.47, P < 0.001). Conclusions A reduction of BNP >46% at hospital discharge

  1. 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.

  2. Usefulness of non-invasive measurement of cardiac output during sub-maximal exercise to predict outcome in patients with chronic heart failure.

    PubMed

    Goda, Ayumi; Lang, Chim C; Williams, Paula; Jones, Margaret; Farr, Mary Jane; Mancini, Donna M

    2009-12-01

    Peak oxygen consumption (Vo(2)) is a powerful prognostic predictor of survival in patients with chronic heart failure (CHF) because it provides an indirect assessment of a patient's ability to increase cardiac output (CO). However, many patients with CHF who undergo cardiopulmonary exercise testing are unable to perform maximal exercise. New metabolic carts coupled with the inert gas rebreathing technique provide a noninvasive measurement of CO. Whether the noninvasive measurement of CO at a fixed submaximal workload can predict outcome is unknown. This study's population comprised 259 patients (mean age 54 +/- 14 years, mean left ventricular ejection fraction 27 +/- 14%) with CHF who underwent symptom-limited incremental cardiopulmonary exercise testing. Vo(2) and CO were measured at rest, at 25 W, and at peak exercise. Submaximal exercise was defined as <80% peak Vo(2). Among 259 patients, 145 had Vo(2) at 25 W <80% of peak. Vo(2) at 25 W averaged 9.3 +/- 1.8 ml/kg/min. This Vo(2) represented 62 +/- 11% of peak Vo(2), which averaged 15.4 +/- 4.4 ml/kg/min. Prospective follow-up averaged 521 +/- 337 days. In this cohort, there were 15 outcome events (death, urgent heart transplantation, or implantation of a left ventricular assist device as a bridge to transplantation). On univariate Cox hazard analysis, CO at 25 W (hazard ratio 0.64, 95% confidence interval 0.48 to 0.84, p = 0.002) was found to be significant predictor of events of outcome. In conclusion, CO at 25 W measured noninvasively during submaximal exercise may have potential value as a predictor of outcomes in patients with CHF.

  3. Predicting survival in heart failure case and control subjects by use of fully automated methods for deriving nonlinear and conventional indices of heart rate dynamics

    NASA Technical Reports Server (NTRS)

    Ho, K. K.; Moody, G. B.; Peng, C. K.; Mietus, J. E.; Larson, M. G.; Levy, D.; Goldberger, A. L.

    1997-01-01

    BACKGROUND: Despite much recent interest in quantification of heart rate variability (HRV), the prognostic value of conventional measures of HRV and of newer indices based on nonlinear dynamics is not universally accepted. METHODS AND RESULTS: We have designed algorithms for analyzing ambulatory ECG recordings and measuring HRV without human intervention, using robust methods for obtaining time-domain measures (mean and SD of heart rate), frequency-domain measures (power in the bands of 0.001 to 0.01 Hz [VLF], 0.01 to 0.15 Hz [LF], and 0.15 to 0.5 Hz [HF] and total spectral power [TP] over all three of these bands), and measures based on nonlinear dynamics (approximate entropy [ApEn], a measure of complexity, and detrended fluctuation analysis [DFA], a measure of long-term correlations). The study population consisted of chronic congestive heart failure (CHF) case patients and sex- and age-matched control subjects in the Framingham Heart Study. After exclusion of technically inadequate studies and those with atrial fibrillation, we used these algorithms to study HRV in 2-hour ambulatory ECG recordings of 69 participants (mean age, 71.7+/-8.1 years). By use of separate Cox proportional-hazards models, the conventional measures SD (P<.01), LF (P<.01), VLF (P<.05), and TP (P<.01) and the nonlinear measure DFA (P<.05) were predictors of survival over a mean follow-up period of 1.9 years; other measures, including ApEn (P>.3), were not. In multivariable models, DFA was of borderline predictive significance (P=.06) after adjustment for the diagnosis of CHF and SD. CONCLUSIONS: These results demonstrate that HRV analysis of ambulatory ECG recordings based on fully automated methods can have prognostic value in a population-based study and that nonlinear HRV indices may contribute prognostic value to complement traditional HRV measures.

  4. A Thermodynamically-Based Mesh Objective Work Potential Theory for Predicting Intralaminar Progressive Damage and Failure in Fiber-Reinforced Laminates

    NASA Technical Reports Server (NTRS)

    Pineda, Evan J.; Waas, Anthony M.

    2012-01-01

    A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Damage is considered to be the effect of any structural changes in a material that manifest as pre-peak non-linearity in the stress versus strain response. Conversely, failure is taken to be the effect of the evolution of any mechanisms that results in post-peak strain softening. It is assumed that matrix microdamage is the dominant damage mechanism in continuous fiber-reinforced polymer matrix laminates, and its evolution is controlled with a single ISV. Three additional ISVs are introduced to account for failure due to mode I transverse cracking, mode II transverse cracking, and mode I axial failure. Typically, failure evolution (i.e., post-peak strain softening) results in pathologically mesh dependent solutions within a finite element method (FEM) setting. Therefore, consistent character element lengths are introduced into the formulation of the evolution of the three failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs is derived. The theory is implemented into commercial FEM software. Objectivity of total energy dissipated during the failure process, with regards to refinements in the FEM mesh, is demonstrated. The model is also verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared to the experiments.

  5. Risk Analysis and Prediction of Floor Failure Mechanisms at Longwall Face in Parvadeh-I Coal Mine using Rock Engineering System (RES)

    NASA Astrophysics Data System (ADS)

    Aghababaei, Sajjad; Saeedi, Gholamreza; Jalalifar, Hossein

    2016-05-01

    The floor failure at longwall face decreases productivity and safety, increases operation costs, and causes other serious problems. In Parvadeh-I coal mine, the timber is used to prevent the puncture of powered support base into the floor. In this paper, a rock engineering system (RES)-based model is presented to evaluate the risk of floor failure mechanisms at the longwall face of E 2 and W 1 panels. The presented model is used to determine the most probable floor failure mechanism, effective factors, damaged regions and remedial actions. From the analyzed results, it is found that soft floor failure is dominant in the floor failure mechanism at Parvadeh-I coal mine. The average of vulnerability index (VI) for soft, buckling and compressive floor failure mechanisms was estimated equal to 52, 43 and 30 for both panels, respectively. By determining the critical VI for soft floor failure mechanism equal to 54, the percentage of regions with VIs beyond the critical VI in E 2 and W 1 panels is equal to 65.5 and 30, respectively. The percentage of damaged regions showed that the excess amount of used timber to prevent the puncture of weak floor below the powered support base is equal to 4,180,739 kg. RES outputs and analyzed results showed that setting and yielding load of powered supports, length of face, existent water at face, geometry of powered supports, changing the cutting pattern at longwall face and limiting the panels to damaged regions with supercritical VIs could be considered to control the soft floor failure in this mine. The results of this research could be used as a useful tool to identify the damaged regions prior to mining operation at longwall panel for the same conditions.

  6. A simple approach to modeling ductile failure.

    SciTech Connect

    Wellman, Gerald William

    2012-06-01

    Sandia National Laboratories has the need to predict the behavior of structures after the occurrence of an initial failure. In some cases determining the extent of failure, beyond initiation, is required, while in a few cases the initial failure is a design feature used to tailor the subsequent load paths. In either case, the ability to numerically simulate the initiation and propagation of failures is a highly desired capability. This document describes one approach to the simulation of failure initiation and propagation.

  7. Kidney Failure

    MedlinePlus

    ... Dialysis or Transplant Paying for Kidney Failure Treatment Contact Us Health Information Center Phone: 1-800-860- ... to share this content freely. October 2, 2013 Contact Us Health Information Center Phone: 1-800-860- ...

  8. Heart Failure

    MedlinePlus

    ... for people who can't tolerate ACE inhibitors. Beta blockers. This class of drugs not only slows your ... rhythms and lessen your chance of dying unexpectedly. Beta blockers may reduce signs and symptoms of heart failure, ...

  9. High flow nasal oxygen in acute respiratory failure.

    PubMed

    Ricard, J-D

    2012-07-01

    Use of high flow nasal cannula oxygen (HFNC) is increasingly popular in adult ICUs for patients with acute hypoxemic respiratory failure. This is the result of the successful long-term use of HFNC in the neonatal field and recent clinical data in adults indicating beneficial effects of HFNC over conventional facemask oxygen therapy. HFNC rapidly alleviates symptoms of respiratory distress and improves oxygenation by several mechanisms, including deadspace washout, reduction in oxygen dilution and in inspiratory nasopharyngeal resistance, a moderate positive airway pressure effect that may generate alveolar recruitment and an overall greater tolerance and comfort with the interface and the heated and humidified inspired gases. Indications of HFNC are broad, encompassing most if not all causes of acute hypoxemic respiratory failure. HFNC can also provide oxygen during invasive procedures, and be used to prevent or treat post-extubation respiratory failure. HFNC may also alleviate respiratory distress in patients at a palliative stage. Although observational studies suggest that HFNC might reduce the need for intubation in acute hypoxemic respiratory failure; such a reduction has not yet been demonstrated. Beyond this potential additional effect on outcome, the evidence already published argues in favor of the large use of HFNC as first line therapy for acute respiratory failure.

  10. The ratio of oleic-to-stearic acid in the prostate predicts biochemical failure after radical prostatectomy for localized prostate cancer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our study examined lifestyle-related factors that may influence the prognosis of clinically localized prostate cancer, we evaluated the relative impact of obesity and prostatic fatty acid concentrations at diagnosis on risk of biochemical failure following radical prostatectomy. Height and weight w...

  11. Heart failure

    PubMed Central

    2011-01-01

    Introduction Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of multidisciplinary interventions for heart failure? What are the effects of exercise in people with heart failure? What are the effects of drug treatments for heart failure? What are the effects of devices for treatment of heart failure? What are the effects of coronary revascularisation for treatment of heart failure? What are the effects of drug treatments in people at high risk of heart failure? What are the effects of treatments for diastolic heart failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 80 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: aldosterone receptor antagonists, amiodarone, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, anticoagulation, antiplatelet agents, beta-blockers, calcium

  12. Heart failure

    PubMed Central

    2010-01-01

    Introduction Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of non-drug treatments, and of drug and invasive treatments, for heart failure? What are the effects of angiotensin-converting enzyme inhibitors in people at high risk of heart failure? What are the effects of treatments for diastolic heart failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 85 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: aldosterone receptor antagonists, amiodarone, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, anticoagulation, antiplatelet agents, beta-blockers, calcium channel blockers, cardiac resynchronisation therapy, digoxin (in people already receiving diuretics and angiotensin-converting enzyme inhibitors), exercise, hydralazine plus isosorbide dinitrate, implantable cardiac

  13. Does Lymphovascular Invasion Predict Regional Nodal Failure in Breast Cancer Patients With Zero to Three Positive Lymph Nodes Treated With Conserving Surgery and Radiotherapy? Implications for Regional Radiation

    SciTech Connect

    Boutrus, Rimoun; Abi-Raad, Rita; Niemierko, Andrzej; Brachtel, Elena F.; Rizk, Levi; Kelada, Alexandra; Taghian, Alphonse G.

    2010-11-01

    Purpose: To examine the relationship between lymphovascular invasion (LVI) and regional nodal failure (RNF) in breast cancer patients with zero to three positive nodes treated with breast-conservation therapy (BCT). Methods and Materials: The records of 1,257 breast cancer patients with zero to three positive lymph nodes were reviewed. All patients were treated with BCT at Massachusetts General Hospital from 1980 to December 2003. Lymphovascular invasion was diagnosed by hematoxylin and eosin-stained sections and in some cases supported by immunohistochemical stains. Regional nodal failure was defined as recurrence in the ipsilateral supraclavicular, axillary, or internal mammary lymph nodes. Regional nodal failure was diagnosed by clinical and/or radiologic examination. Results: The median follow-up was 8 years (range, 0.1-21 years). Lymphovascular invasion was present in 211 patients (17%). In univariate analysis, patients with LVI had a higher rate of RNF (3.32% vs. 1.15%; p = 0.02). In multivariate analysis, only tumor size, grade, and local failure were significant predictors of RNF (p = 0.049, 0.013, and 0.0001, respectively), whereas LVI did not show a significant relationship with RNF (hazard ratio = 2.07; 95% CI, 0.8-5.5; p = 0.143). The presence of LVI in the T2/3 population did not increase the risk of RNF over that for those with no LVI (p = 0.15). In addition, patients with Grade 3 tumors and positive LVI did not have a higher risk of RNF than those without LVI (p = 0.96). Conclusion: These results suggest that LVI can not be used as a sole indicator for regional nodal irradiation in breast cancer patients with zero to three positive lymph nodes treated with BCT.

  14. [Heart failure and anemia].

    PubMed

    Reda, S; Motloch, L J; Hoppe, U C

    2013-09-01

    Chronic heart failure has an age-dependent prevalence of 2% and is therefore one of the most frequent diseases in western societies. A reduced hemoglobin concentration according to the definition of the World Health Organization is a common comorbidity affecting more than half of all heart failure patients. Elderly patients, patients suffering from renal impairment and women are more likely to develop anemia but a definitive etiology of anemia is only identified in the minority of cases. Anemia is associated with a poor clinical status and a greater risk of hospitalization and is a predictive factor for increased mortality. The incidence of anemia appears to increase with a poorer functional class. Intravenous iron therapy improves the exercise capacity in patients with systolic heart failure and iron deficiency and is currently being recommended for patients with persistent symptoms despite optimal medical and device therapy. However, erythropoietin-stimulating agents as a treatment for anemia in chronic heart failure have failed to improve clinical outcome in a large randomized trial. In patients with heart failure but with maintained ejection fraction, anemia is also associated with a poor prognosis. Specific therapeutic recommendations for these patients are still not available.

  15. Kidney (Renal) Failure

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Kidney Failure Kidney failure, also known as renal failure, ... evaluated? How is kidney failure treated? What is kidney (renal) failure? The kidneys are designed to maintain ...

  16. Early Failure of Frontline Rituximab-containing Chemoimmunotherapy in Diffuse Large B-Cell Lymphoma does not Predict Futility of Autologous Hematopoietic Cell Transplantation

    PubMed Central

    Hamadani, Mehdi; Hari, Parameswaran N.; Zhang, Ying; Carreras, Jeanette; Akpek, Görgün; Aljurf, Mahmoud D.; Ayala, Ernesto; Bachanova, Veronika; Chen, Andy I.; Chen, Yi-Bin; Costa, Luciano J.; Fenske, Timothy S.; Freytes, César O.; Ganguly, Siddhartha; Hertzberg, Mark S.; Holmberg, Leona A.; Inwards, David J.; Kamble, Rammurti T.; Kanfer, Edward J.; Lazarus, Hillard M.; Marks, David I.; Nishihori, Taiga; Olsson, Richard; Reddy, Nishitha M.; Rizzieri, David A.; Savani, Bipin N.; Solh, Melhem; Vose, Julie M.; Wirk, Baldeep; Maloney, David G.; Smith, Sonali M.; Montoto, Silvia; Saber, Wael

    2014-01-01

    The poor prognosis of diffuse large B-cell lymphoma (DLBCL) patients relapsing within 1-year of initial diagnosis after first-line rituximab-based chemoimmunotherapy has created controversy about the role of autologous transplantation (auto-HCT) in this setting. We compared auto-HCT outcomes of chemosensitive DLBCL patients between 2000 and 2011 in two cohorts based on time to relapse from diagnosis. The early rituximab failure (ERF) cohort consisted of patients with primary refractory disease or those with first relapse within 1-year of initial diagnosis. The ERF cohort was compared with those relapsing >1-year after initial diagnosis (Late Rituximab Failure [LRF] cohort). ERF and LRF cohorts included 300 and 216 patients, respectively. Non-relapse mortality (NRM), progression/relapse, progression-free survival (PFS) and overall survival (OS) of ERF vs. LRF cohorts at 3-years were 9% (95%CI 6–13) vs. 9% (95%CI 5–13), 47% (95%CI 41–52) vs. 39% (95%CI 33–46), 44% (95%CI 38–50) vs. 52% (95%CI 45–59) and 50% (95 CI 44–56) vs. 67% (95%CI 60–74), respectively. On multivariate analysis, ERF was not associated with higher NRM (relative risk (RR) 1.31, p=0.34). ERF cohort had a higher risk of treatment failure (progression/relapse or death) (RR 2.08, p<0.001) and overall mortality (RR 3.75, p<0.001) within the first 9 months post auto-HCT. Beyond this period, PFS and OS were not significantly different between ERF and LRF cohorts. Auto-HCT provides durable disease control to a sizeable subset of DLBCL despite ERF (3-year PFS 44%), and remains the standard-of-care in chemosensitive DLBCL regardless of the timing of disease relapse. PMID:25008330

  17. Toward full-chip prediction of yield-limiting contact patterning failure: correlation of simulated image parameters to advanced contact metrology metrics

    NASA Astrophysics Data System (ADS)

    Sturtevant, John L.; Chou, Dyiann

    2006-03-01

    Electrical failure due to incomplete contacts or vias has arisen as one of the primary modes of yield loss for 130 nm and below designs in manufacturing. Such failures are generally understood to arise from both random and systematic sources. The addition of redundant vias, where possible, has long been an accepted DFM practice for mitigating the impact of random defects. Incomplete vias are often characterized by having a diameter near the target dimension but a depth of less than 100% of target. As such, it is a difficult problem to diagnose and debug in-line, since bright and dark field optical inspection systems cannot typically distinguish between a closed, partially open and fully open contact. Advanced metrology systems have emerged in recent years to meet this challenge, but no perfect manufacturing solution has yet been identified for full field verification of all contacts. Voltage Contrast (VC) SEM metrology biases the wafer to directly measure electrical conductivity after fill / polish, and can therefore easily discern a lack of electrical connection to the underlying conductor caused by incomplete photo, etch, or fill processing. While an entire wafer can in principal be VC scanned, throughput limitations dictate very sparse sampling in manufacturing. SEM profile grading (PG) leverages the rich content of the secondary electron waveform to decipher information about the bottom of the contact. Several authors have demonstrated an excellent response of the Profile Grade to intentional defocus vectors. However, the SEM can only target discreet or single digit groupings of contacts, and therefore requires intelligent guidance to identify those contacts which are most prone to failure, enabling protection of the fab WIP. An a-priori knowledge of which specific contacts in a layout are most likely to fail would prove very useful for proactive inspection in manufacturing. Model based pre-manufacturing verification allows for such knowledge to be communicated

  18. Experimental aspects and mechanical modeling paradigms for the prediction of degradation and failure in nanocomposite materials subjected to fatigue loading conditions

    NASA Astrophysics Data System (ADS)

    Averett, Rodney D.

    2008-10-01

    The objective of the current research was to contribute to the area of mechanics of composite polymeric materials. This objective was reached by establishing a quantitative assessment of the fatigue strength and evolution of mechanical property changes during fatigue loading of nanocomposite fibers and films. Both experimental testing and mathematical modeling were used to gain a fundamental understanding of the fatigue behavior and material changes that occurred during fatigue loading. In addition, the objective of the study was to gain a qualitative and fundamental understanding of the failure mechanisms that occurred between the nanoagent and matrix in nanocomposite fibers. This objective was accomplished by examining scanning electron microscopy (SEM) fractographs. The results of this research can be used to better understand the behavior of nanocomposite materials in applications where degradation due to fatigue and instability of the composite under loading conditions may be a concern. These applications are typically encountered in automotive, aerospace, and civil engineering applications where fatigue and/or fracture are primary factors that contribute to failure.

  19. Progressive Failure Analysis Methodology for Laminated Composite Structures

    NASA Technical Reports Server (NTRS)

    Sleight, David W.

    1999-01-01

    A progressive failure analysis method has been developed for predicting the failure of laminated composite structures under geometrically nonlinear deformations. The progressive failure analysis uses C(exp 1) shell elements based on classical lamination theory to calculate the in-plane stresses. Several failure criteria, including the maximum strain criterion, Hashin's criterion, and Christensen's criterion, are used to predict the failure mechanisms and several options are available to degrade the material properties after failures. The progressive failure analysis method is implemented in the COMET finite element analysis code and can predict the damage and response of laminated composite structures from initial loading to final failure. The different failure criteria and material degradation methods are compared and assessed by performing analyses of several laminated composite structures. Results from the progressive failure method indicate good correlation with the existing test data except in structural applications where interlaminar stresses are important which may cause failure mechanisms such as debonding or delaminations.

  20. Heart Failure in South America

    PubMed Central

    Bocchi, Edimar Alcides

    2013-01-01

    Continued assessment of temporal trends in mortality and epidemiology of specific heart failure in South America is needed to provide a scientific basis for rational allocation of the limited health care resources, and strategies to reduce risk and predict the future burden of heart failure. The epidemiology of heart failure in South America was reviewed. Heart failure is the main cause of hospitalization based on available data from approximately 50% of the South American population. The main etiologies of heart failure are ischemic, idiopathic dilated cardiomyopathy, valvular, hypertensive and chagasic etiologies. In endemic areas, Chagas heart disease may be responsible by 41% of the HF cases. Also, heart failure presents high mortality especially in patients with Chagas etiology. Heart failure and etiologies associated with heart failure may be responsible for 6.3% of causes of deaths. Rheumatic fever is the leading cause of valvular heart disease. However, a tendency to reduction of HF mortality due to Chagas heart disease from 1985 to 2006, and reduction in mortality due to HF from 1999 to 2005 were observed in selected states in Brazil. The findings have important public health implications because the allocation of health care resources, and strategies to reduce risk of heart failure should also consider the control of neglected Chagas disease and rheumatic fever in South American countries. PMID:23597301

  1. Strategies of learning from failure.

    PubMed

    Edmondson, Amy C

    2011-04-01

    Many executives believe that all failure is bad (although it usually provides Lessons) and that Learning from it is pretty straightforward. The author, a professor at Harvard Business School, thinks both beliefs are misguided. In organizational life, she says, some failures are inevitable and some are even good. And successful learning from failure is not simple: It requires context-specific strategies. But first leaders must understand how the blame game gets in the way and work to create an organizational culture in which employees feel safe admitting or reporting on failure. Failures fall into three categories: preventable ones in predictable operations, which usually involve deviations from spec; unavoidable ones in complex systems, which may arise from unique combinations of needs, people, and problems; and intelligent ones at the frontier, where "good" failures occur quickly and on a small scale, providing the most valuable information. Strong leadership can build a learning culture-one in which failures large and small are consistently reported and deeply analyzed, and opportunities to experiment are proactively sought. Executives commonly and understandably worry that taking a sympathetic stance toward failure will create an "anything goes" work environment. They should instead recognize that failure is inevitable in today's complex work organizations.

  2. Peridynamic Modeling of Fracture and Failure of Materials

    DTIC Science & Technology

    2013-08-02

    failure loads approach the measured values. 4.3.2.1 Laminated plate with a center hole The quasi-isotropic AS4/3501-6 carbon/ epoxy composite ...both the failure progression and residual strength of monolithic and composite laminates. Predicting damage and residual strengths of composite ...demonstrated by predicting failure loads and final failure peridynamics, composites , progressive failure 42 Erdogan Madenci 52-250-1399

  3. An Investigation of the Effects of a Diagnostic Prescriptive Kindergarten Program on the Predicted Reading Levels of Children Identified as Potential Reading Failures. Final Report.

    ERIC Educational Resources Information Center

    Stank, Peggy L.; Hayes, Robert B.

    An experimental design with experimental and control groups was used to evaluate the effect of a diagnostic structured kindergarten program upon the predicted reading levels of low income area children. The effect was compared with the effect of the traditional kindergarten program. The effects of the two curricula upon the total group of children…

  4. PSA nadir as a predictive factor for biochemical disease-free survival and overall survival following whole-gland salvage HIFU following radiotherapy failure

    PubMed Central

    Shah, Taimur; Peters, Max; Kanthabalan, Abi; McCartan, Neil; Fatola, Yomi; van der Voort van Zyp, Jochem; van Vulpen, Marco; Freeman, Alex; Moore, Caroline M.; Arya, Manit; Emberton, Mark; Ahmed, Hashim U.

    2016-01-01

    Background Treatment options for radio-recurrent prostate cancer are either androgen deprivation therapy or salvage prostatectomy. Whole-gland HIFU might have a role in this setting. Methods An independent HIFU registry collated consecutive cases of HIFU. Between 2005 and 2012 we identified 50 men who underwent whole-gland HIFU following histological confirmation of localized disease following prior external beam radiotherapy (2005-2012). No upper threshold was applied for risk category, Prostate Specific Antigen (PSA), or Gleason grade either at presentation or at time of failure. Progression was defined as a composite with either biochemical failure (Phoenix criteria [PSA>nadir+2ng/mL]), start of systemic therapies or metastases. Results Median age (IQR), pre-treatment PSA (IQR), and Gleason score (range), were 68years (64-72), 5.9ng/mL (2.2-11.3), and 7 (6-9), respectively. Median follow-up was 64months (49-84). 24/50 (48%) avoided androgen deprivation therapies. 28/50 (56%) achieved a PSA-nadir <0.5ng/ml. 15/50 (30%) had a nadir ≥0.5ng/ml. 7/50 (14%) did not nadir (PSA non-responders). Actuarial 1, 3 and 5-year PFS was 72%, 40% and 31%, respectively. Actuarial 1, 3, and 5-year OS was 100%, 94% and 87%, respectively. When comparing patients with PSA nadir <0.5ng/ml, nadir ≥0.5 and non-responders a statistically significant difference in PFS was seen (p<0.0001). 3-year PFS in each group was 57%, 20% and 0%, respectively. 5-year overall survival was 96%, 100% and 38%, respectively. Early in the learning curve, between 2005-2007, 3/50 (6%) developed a fistula. Intervention for bladder outlet obstruction was needed in 27/50 (54%). Patient-reported outcome measures questionnaires showed incontinence (any pad-use) as 8/26 (31%). Conclusions In our series of high-risk patients, in whom 30-50% may have micro-metastases, disease control rates were promising in PSA-responders, however with significant morbidity. Additionally, post-HIFU PSA-nadir appears to be an

  5. Heart failure.

    PubMed

    Braunwald, Eugene

    2013-02-01

    Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches.

  6. Infant flow biphasic nasal continuous positive airway pressure (BP- NCPAP) vs. infant flow NCPAP for the facilitation of extubation in infants' ≤ 1,250 grams: a randomized controlled trial

    PubMed Central

    2012-01-01

    Abstract Background The use of mechanical ventilation is associated with lung injury in preterm infants and therefore the goal is to avoid or minimize its use. To date there is very little consensus on what is considered the "best non-invasive ventilation mode" to be used post-extubation. The objective of this study was to compare the effectiveness of biphasic nasal continuous positive airway pressure (BP-NCPAP) vs. NCPAP in facilitating sustained extubation in infants ≤ 1,250 grams. Methods We performed a randomized controlled trial of BP-NCPAP vs. NCPAP in infants ≤ 1,250 grams extubated for the first time following mechanical ventilation since birth. Infants were extubated using preset criteria or at the discretion of the attending neonatologist. The primary outcome was the incidence of sustained extubation for 7 days. Secondary outcomes included incidence of adverse events and short-term neonatal outcomes. Results Sixty-seven infants received BP-NCPAP and 69 NCPAP. Baseline characteristics were similar between groups. The trial was stopped early due to increased use of non-invasive ventilation from birth, falling short of our calculated sample size of 141 infants per group. The incidence of sustained extubation was not statistically different between the BP-NCPAP vs. NCPAP group (67% vs. 58%, P = 0.27). The incidence of adverse events and short-term neonatal outcomes were similar between the two groups (P > 0.05) except for retinopathy of prematurity which was noted to be higher (P = 0.02) in the BP-NCPAP group. Conclusions Biphasic NCPAP may be used to assist in weaning from mechanical ventilation. The effectiveness and safety of BP-NCPAP compared to NCPAP needs to be confirmed in a large multi-center trial as our study conclusions are limited by inadequate sample size. Clinical Trials Registration # NCT00308789 Source of support Grant # 06-06, Physicians Services Incorporated Foundation, Toronto, Canada. Summit technologies Inc. provided additional NCPAP

  7. Predicting drowsy driving in real-time situations: Using an advanced driving simulator, accelerated failure time model, and virtual location-based services.

    PubMed

    Wang, Junhua; Sun, Shuaiyi; Fang, Shouen; Fu, Ting; Stipancic, Joshua

    2017-02-01

    This paper aims to both identify the factors affecting driver drowsiness and to develop a real-time drowsy driving probability model based on virtual Location-Based Services (LBS) data obtained using a driving simulator. A driving simulation experiment was designed and conducted using 32 participant drivers. Collected data included the continuous driving time before detection of drowsiness and virtual LBS data related to temperature, time of day, lane width, average travel speed, driving time in heavy traffic, and driving time on different roadway types. Demographic information, such as nap habit, age, gender, and driving experience was also collected through questionnaires distributed to the participants. An Accelerated Failure Time (AFT) model was developed to estimate the driving time before detection of drowsiness. The results of the AFT model showed driving time before drowsiness was longer during the day than at night, and was longer at lower temperatures. Additionally, drivers who identified as having a nap habit were more vulnerable to drowsiness. Generally, higher average travel speeds were correlated to a higher risk of drowsy driving, as were longer periods of low-speed driving in traffic jam conditions. Considering different road types, drivers felt drowsy more quickly on freeways compared to other facilities. The proposed model provides a better understanding of how driver drowsiness is influenced by different environmental and demographic factors. The model can be used to provide real-time data for the LBS-based drowsy driving warning system, improving past methods based only on a fixed driving.

  8. Autoimmune premature ovarian failure

    PubMed Central

    2017-01-01

    Premature ovarian failure (POF), also termed as primary ovarian insufficiency (POI), is a highly heterogenous condition affecting 0.5-3.0% of women in childbearing age. These young women comprise quite a formidable group with unique physical and psychological needs that require special attention. Premature ovarian senescence (POS) in all of its forms evolves insidiously as a basically asymptomatic process, leading to complete loss of ovarian function, and POI/POF diagnoses are currently made at relatively late stages. Well-known and well-documented risk factors exist, and the presence or suspicion of autoimmune disorder should be regarded as an important one. Premature ovarian failure is to some degree predictable in its occurrence and should be considered while encountering young women with loss of menstrual regularity, especially when there is a concomitant dysfunction in the immune system. PMID:28250725

  9. Early measurement of CD34+ cells in peripheral blood after cyclophosphamide and granulocyte colony-stimulating factor treatment predicts later CD34+ mobilisation failure and is a possible criterion for guiding “on demand” use of plerixafor

    PubMed Central

    Milone, Giuseppe; Tripepi, Giovanni; Martino, Massimo; Ancora, Flavia; Bartolozzi, Benedetta; Spadaro, Andrea; Nozzoli, Chiara; La Fauci, Alessia; Amico, Irene; Leotta, Salvatore; Poidomani, Massimo; Irrera, Giuseppe; Iacopino, Pasquale; Saccardi, Riccardo; Guidi, Stefano; Bosi, Alberto

    2013-01-01

    Background Early identification of predictive factors of failure to mobilise CD34+ cells could enable rational use of plerixafor during first mobilisation, avoiding the need for a second mobilisation course. However, “on demand” administration of plerixafor needs to be driven by established parameters to avoid inappropriate use. Materials and methods To address this issue, we studied the value of the peripheral blood CD34+ count, measured early (on days +10, +11, +12 and +13), in predicting the mobilisation outcome in the ensuing days. We retrospectively collected data from three Italian centres on 233 patients affected by multiple myeloma or lymphoma who underwent a first or second attempt at mobilisation with cyclophosphamide 4 g/m2 and granulocyte colony-stimulating factor. To assess the diagnostic value of peripheral blood white blood cell and CD34+ cell counts with respect to “mobilisation failure”, we considered failed mobilisation as “disease” and the CD34+ cell count in peripheral blood, on a specific day, as a “diagnostic test”. For various thresholds, we measured sensitivity, false positive rate, specificity and positive predictive value (PPV) as well as the area under the receiver-operating characteristic curves (AUC). Results A CD34+ cell count <10×106/L on day 13 had high sensitivity (1.00) and high specificity (1.00) for predicting subsequent mobilisation failure, with an AUC of 1.0. However, good prediction was also obtained using a lower threshold (CD34+ cell count: <6×106/L) at an earlier time (day 12). The PPV of the day 13 threshold was 1.00 while that of the day 12 one was 0.87. Discussion We propose that patients with <6×106/L CD34+ cells in peripheral blood on day 12 and <10×106/L on day 13 following mobilisation with cyclophosphamide 4 g/m2 and granulocyte colony-stimulating factor are candidates for “on demand” use of plerixafor, making the administration of this expensive agent more efficient and avoiding its

  10. The cuff-leak test: what are we measuring?

    PubMed

    De Backer, Daniel

    2005-02-01

    Stridor is one of the most frequent causes of early extubation failure. The cuff-leak test may help to identify patients at risk to develop post-extubation laryngeal edema. However the discrimination power of the cuff-leak test is highly variable and can be use, at best, to detect patients at risk to develop edema but should not be used to postpone extubation as tracheal extubation can still be successful in many patients with a positive test. In this editorial, the author discuss the factors influencing the leak and hence its predictive value.

  11. Do uterine natural killer cell numbers in peri-implantation endometrium predict hypertensive disorder in pregnancy in women with a history of reproductive failure?

    PubMed

    Wong, Alice Wai Yee; Archer, Bethan; Mariee, Najat; Li, Tin Chiu; Laird, Susan M

    2014-12-01

    The aim of this study was to investigate whether or not increased uterine natural killer (uNK) cell numbers in the peri-implantation endometrium are associated with an increased risk of hypertensive disorders in a subsequent pregnancy. This is a retrospective study including 80 women with a history of unexplained recurrent miscarriage or recurrent implantation failure. Precisely timed endometrial biopsies were obtained from women 7-9 days after the luteinising hormone surge. uNK cells were immunostained for CD56+ and expressed as a percentage of total stromal cells. Patients were defined as having a high uNK cell count if the percentage of total stromal cells was more than 13.9%. Five out of 29 (17.2%) women in the high uNK cell count group and 5 out of 51 (9.8%) women in the normal uNK cell count group developed gestational hypertension. Pre-eclampsia was diagnosed in 2 (6.9%) patients in the high uNK cell count group and 1 (2.0%) patient from the normal uNK cell count group. There was no significant difference in the incidence of either gestational hypertension (P=0.483) and pre-eclampsia (P=0.296) between groups. The overall incidence of hypertensive disease in women with high uNK cell count (24.1%) was two times higher than women with normal uNK cell count (11.8%), but it was not statistically significant (P=0.208). An increased uNK cells count in the peri-implantation period in a cycle prior to conception did not appear to significantly increase the likelihood of hypertensive disease of pregnancy.

  12. WE-G-BRD-09: Prediction of Local Control/Failure by Using Feature Histogram Selection in Follow-Up T2-Weighted MR Image in Spinal Tumors After Stereotactic Body Radiation Therapy

    SciTech Connect

    Zhou, J; Harb, J; Jawad, M; Yee, S; Schulze, D; Liang, J; Grills D, Yan

    2014-06-15

    Purpose: In follow-up T2-weighted MR images of spinal tumor patients treated with stereotactic body radiation therapy (SBRT), high intensity features embedded in dark surroundings may suggest a local failure (LF). We investigated image intensity histogram in imaging features to predict LF and local control (LC). Methods: Sixty-seven spinal tumors were treated with SBRT at our institution with scheduled follow-up MR T2-weighted (TR 3200–6600ms; TE 75-132ms) imaging. The LF group included 10 tumors with 8.7 months median follow-up, while the LC group had 11 tumors with 24.1 months median follow-up. The follow-up images were fused to the planning CT. Image intensity histograms of the GTV were calculated. Voxels in greater than 90% (V90), 80% (V80), and peak (Vpeak) of the histogram were grouped into sub-ROIs to determine the best feature histogram. The intensity of each sub-ROI was evaluated using the mean T2-weighted signal ratio (intensity in sub-ROI / intensity in normal vertebrae). An ROC curve in predicting LF for each sub-ROI was calculated to determine the best feature histogram parameter for LF prediction. Results: Mean T2-weighted signal ratio in the LF group was significantly higher than that in the LC group for all sub-ROIs (1.1±0.4 vs. 0.7±0.2, 1.2±0.4 vs. 0.8±0.2, 1.4±0.5 vs. 0.8±0.2, for V90, V80, and Vpeak, p=0.02, 0.02, and 0.002, respectively). The corresponding areas-under-curve (AUC) of ROC were 0.78, 0.80, and 0.87, p=0.02, 0.03, 0.004, respectively. No correlation was found between T2-weighted signal ratio in Vpeak and follow-up time (Pearson's ρ=0.15). Conclusion: Increased T2-weighted signal can be used to identify local failure while decreased signal indicates local control after spinal SBRT. By choosing the best histogram parameter (here the Vpeak), the AUC of the ROC can be substantially improved, which implies reliable prediction of LC and LF. These results are being further studied and validated with large multi-institutional data.

  13. Usefulness of combining admission brain natriuretic peptide (BNP) plus hospital discharge bioelectrical impedance vector analysis (BIVA) in predicting 90 days cardiovascular mortality in patients with acute heart failure.

    PubMed

    Santarelli, Simona; Russo, Veronica; Lalle, Irene; De Berardinis, Benedetta; Navarin, Silvia; Magrini, Laura; Piccoli, Antonio; Codognotto, Marta; Castello, Luigi Maria; Avanzi, Gian Carlo; Villacorta, Humberto; Precht, Bernardo Luiz Campanário; de Araújo Porto, Pilar Barreto; Villacorta, Aline Sterque; Di Somma, Salvatore

    2016-12-16

    Heart failure is a disease characterized by high prevalence and mortality, and frequent rehospitalizations. The aim of this study is to investigate the prognostic power of combining brain natriuretic peptide (BNP) and congestion status detected by bioelectrical impedance vector analysis (BIVA) in acute heart failure patients. This is an observational, prospective, and a multicentre study. BNP assessment was measured upon hospital arrival, while BIVA analysis was obtained at the time of discharge. Cardiovascular deaths were evaluated at 90 days by a follow up phone call. 292 patients were enrolled. Compared to survivors, BNP was higher in the non-survivors group (mean value 838 vs 515 pg/ml, p < 0.001). At discharge, BIVA shows a statistically significant difference in hydration status between survivors and non-survivors [respectively, hydration index (HI) 85 vs 74, p < 0.001; reactance (Xc) 26.7 vs 37, p < 0.001; resistance (R) 445 vs 503, p < 0.01)]. Discharge BIVA shows a prognostic value in predicting cardiovascular death [HI: area under the curve (AUC) 0.715, 95% confidence interval (95% CI) 0.65-0.76; p < 0.004; Xc: AUC 0.712, 95% CI 0.655-0.76, p < 0.007; R: AUC 0.65, 95% CI 0.29-0.706, p < 0.0247]. The combination of BIVA with BNP gives a greater prognostic power for cardiovascular mortality [combined receiving operating characteristic (ROC): AUC 0.74; 95% CI 0.68-0.79; p < 0.001]. In acute heart failure patients, higher BNP levels upon hospital admission, and congestion detected by BIVA at discharge have a significant predictive value for 90 days cardiovascular mortality. The combined use of admission BNP and BIVA discharge seems to be a useful tool for increasing prognostic power in these patients.

  14. Postbuckling failure of composite plates with holes

    NASA Technical Reports Server (NTRS)

    Lee, H. H.; Hyer, M. W.

    1992-01-01

    This paper summarizes a study focused on understanding the failure mechanisms present in a plate with a centrally located circular hole loaded inplane into the postbuckling range of deflections. The study was numerical and experimental in nature and had as a goal the a priori prediction of failure using existing failure data from several sources, together with a stress analysis. The maximum stress failure criterion was used to predict failure and both intra- and interlaminar stresses were considered. Four laminates were considered. The phenomenon of modal interaction, or the jumping from one deformed configuration to another, is discussed. With this jumping, the plate configuration may change from one half-wave in the loading direction to two half-waves in the loading direction. The study concludes that the failure in (+/-45/0/90)2s and (+/-45/2(2))2s laminates is due to fiber compression failure and is predictable. The failure load is, for the most part, independent of response configuration. The (+/-45/0/(6))s laminate fails due to interlaminar shear along the simple support, while the response and failure of the (+/-45)4s laminate is governed to a large degree by material nonlinearities and progressive failure.

  15. Stress-related increases in risk taking and attentional failures predict earlier relapse to smoking in young adults: A pilot investigation.

    PubMed

    Schepis, Ty S; Tapscott, Brian E; Krishnan-Sarin, Suchitra

    2016-04-01

    Substantial evidence links greater impulsivity and stress exposure to poorer smoking cessation outcomes. Results from adolescents also indicate that stress-related change in risk taking can impede cessation attempts. We investigated the effects of stress-related change in impulsivity, risk taking, attention and nicotine withdrawal, and craving in young adult smokers on time to smoking relapse in a relapse analogue paradigm. Twenty-six young adult smokers (50% women; mean age: 20.9 ± 1.8) were exposed to a stress imagery session followed by a contingency management-based relapse analogue paradigm. Participants smoked at least 5 cigarettes daily, with a mean baseline carbon monoxide (CO) level of 13.7 (± 5.1) ppm. Repeated measures analysis of variance (ANOVA) and paired t tests examined stress induction validity and Cox regressions of proportional hazards examined the effects of stress-related changes in nicotine withdrawal, nicotine craving, attention, impulsivity, and risk taking on time to relapse. While stress-related change in impulsivity, nicotine craving and withdrawal did not predict time to relapse (all ps > .10), greater stress-related increases in reaction time (RT) variability (p = .02) were predictive of shorter time to relapse, with trend-level findings for inattention and risk taking. Furthermore, changes in stress-related risk taking affected outcome in women more than in men, with a significant relationship between stress-related change in risk taking only in women (p = .026). Smoking cessation attempts in young adults may be adversely impacted by stress-related increases in risk taking and attentional disruption. Clinicians working with young adults attempting cessation may need to target these stress-related impairments by fostering more adaptive coping and resilience.

  16. Application of a model of plastic porous materials including void shape effects to the prediction of ductile failure under shear-dominated loadings

    NASA Astrophysics Data System (ADS)

    Morin, Léo; Leblond, Jean-Baptiste; Tvergaard, Viggo

    2016-09-01

    An extension of Gurson's famous model (Gurson, 1977) of porous plastic solids, incorporating void shape effects, has recently been proposed by Madou and Leblond (Madou and Leblond, 2012a, 2012b, 2013; Madou et al., 2013). In this extension the voids are no longer modelled as spherical but ellipsoidal with three different axes, and changes of the magnitude and orientation of these axes are accounted for. The aim of this paper is to show that the new model is able to predict softening due essentially to such changes, in the absence of significant void growth. This is done in two steps. First, a numerical implementation of the model is proposed and incorporated into the SYSTUS® and ABAQUS® finite element programmes (through some freely available UMAT (Leblond, 2015) in the second case). Second, the implementation in SYSTUS® is used to simulate previous "numerical experiments" of Tvergaard and coworkers (Tvergaard, 2008, 2009, 2012, 2015a; Dahl et al., 2012; Nielsen et al., 2012) involving the shear loading of elementary porous cells, where softening due to changes of the void shape and orientation was very apparent. It is found that with a simple, heuristic modelling of the phenomenon of mesoscopic strain localization, the model is indeed able to reproduce the results of these numerical experiments, in contrast to Gurson's model disregarding void shape effects.

  17. Light water reactor lower head failure analysis

    SciTech Connect

    Rempe, J.L.; Chavez, S.A.; Thinnes, G.L.

    1993-10-01

    This document presents the results from a US Nuclear Regulatory Commission-sponsored research program to investigate the mode and timing of vessel lower head failure. Major objectives of the analysis were to identify plausible failure mechanisms and to develop a method for determining which failure mode would occur first in different light water reactor designs and accident conditions. Failure mechanisms, such as tube ejection, tube rupture, global vessel failure, and localized vessel creep rupture, were studied. Newly developed models and existing models were applied to predict which failure mechanism would occur first in various severe accident scenarios. So that a broader range of conditions could be considered simultaneously, calculations relied heavily on models with closed-form or simplified numerical solution techniques. Finite element techniques-were employed for analytical model verification and examining more detailed phenomena. High-temperature creep and tensile data were obtained for predicting vessel and penetration structural response.

  18. Wind Turbine Failures - Tackling current Problems in Failure Data Analysis

    NASA Astrophysics Data System (ADS)

    Reder, M. D.; Gonzalez, E.; Melero, J. J.

    2016-09-01

    The wind industry has been growing significantly over the past decades, resulting in a remarkable increase in installed wind power capacity. Turbine technologies are rapidly evolving in terms of complexity and size, and there is an urgent need for cost effective operation and maintenance (O&M) strategies. Especially unplanned downtime represents one of the main cost drivers of a modern wind farm. Here, reliability and failure prediction models can enable operators to apply preventive O&M strategies rather than corrective actions. In order to develop these models, the failure rates and downtimes of wind turbine (WT) components have to be understood profoundly. This paper is focused on tackling three of the main issues related to WT failure analyses. These are, the non-uniform data treatment, the scarcity of available failure analyses, and the lack of investigation on alternative data sources. For this, a modernised form of an existing WT taxonomy is introduced. Additionally, an extensive analysis of historical failure and downtime data of more than 4300 turbines is presented. Finally, the possibilities to encounter the lack of available failure data by complementing historical databases with Supervisory Control and Data Acquisition (SCADA) alarms are evaluated.

  19. Predictive Performance of the Simplified Acute Physiology Score (SAPS) II and the Initial Sequential Organ Failure Assessment (SOFA) Score in Acutely Ill Intensive Care Patients: Post-Hoc Analyses of the SUP-ICU Inception Cohort Study

    PubMed Central

    Møller, Morten Hylander; Krag, Mette; Perner, Anders; Hjortrup, Peter Buhl

    2016-01-01

    Purpose Severity scores including the Simplified Acute Physiology Score (SAPS) II and the Sequential Organ Failure Assessment (SOFA) score are used in intensive care units (ICUs) to assess disease severity, predict mortality and in research. We aimed to assess the predictive performance of SAPS II and the initial SOFA score for in-hospital and 90-day mortality in a contemporary international cohort. Methods This was a post-hoc study of the Stress Ulcer Prophylaxis in the Intensive Care Unit (SUP-ICU) inception cohort study, which included acutely ill adults from ICUs across 11 countries (n = 1034). We compared the discrimination of SAPS II and initial SOFA scores, compared the discrimination of SAPS II in our cohort with the original cohort, assessed the calibration of SAPS II customised to our cohort, and compared the discrimination for 90-day mortality vs. in-hospital mortality for both scores. Discrimination was evaluated using areas under the receiver operating characteristics curves (AUROC). Calibration was evaluated using Hosmer-Lemeshow’s goodness-of-fit Ĉ-statistic. Results AUROC for in-hospital mortality was 0.80 (95% confidence interval (CI) 0.77–0.83) for SAPS II and 0.73 (95% CI 0.69–0.76) for initial SOFA score (P<0.001 for the comparison). Calibration of the customised SAPS II for predicting in-hospital mortality was adequate (P = 0.60). Discrimination of SAPS II was reduced compared with the original SAPS II validation sample (AUROC 0.80 vs. 0.86; P = 0.001). AUROC for 90-day mortality was 0.79 (95% CI 0.76–0.82; P = 0.74 for comparison with in-hospital mortality) for SAPS II and 0.71 (95% CI 0.68–0.75; P = 0.66 for comparison with in-hospital mortality) for the initial SOFA score. Conclusions The predictive performance of SAPS II was similar for in-hospital and 90-day mortality and superior to that of the initial SOFA score, but SAPS II’s performance has decreased over time. Use of a contemporary severity score with improved predictive

  20. Acute kidney failure

    MedlinePlus

    Kidney failure; Renal failure; Renal failure - acute; ARF; Kidney injury - acute ... There are many possible causes of kidney damage. They include: ... cholesterol (cholesterol emboli) Decreased blood flow due to very ...

  1. What Is Heart Failure?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Heart Failure? Heart failure is a condition in which the heart can' ... force. Some people have both problems. The term "heart failure" doesn't mean that your heart has stopped ...

  2. Heart failure - medicines

    MedlinePlus

    CHF - medicines; Congestive heart failure - medicines; Cardiomyopathy - medicines; HF - medicines ... You will need to take most of your heart failure medicines every day. Some medicines are taken ...

  3. Combination of high-sensitivity troponin I and N-terminal pro-B-type natriuretic peptide predicts future hospital admission for heart failure in high-risk hypertensive patients with preserved left ventricular ejection fraction.

    PubMed

    Okuyama, Ryunosuke; Ishii, Junnichi; Takahashi, Hiroshi; Kawai, Hideki; Muramatsu, Takashi; Harada, Masahide; Yamada, Akira; Motoyama, Sadako; Matsui, Shigeru; Naruse, Hiroyuki; Sarai, Masayoshi; Hasegawa, Midori; Watanabe, Eiichi; Suzuki, Atsushi; Hayashi, Mutsuharu; Izawa, Hideo; Yuzawa, Yukio; Ozaki, Yukio

    2017-02-02

    Additional risk stratification may provide more aggressive and focalized preventive treatment to high-risk hypertensive patients according to the Japanese hypertension guidelines. We prospectively investigated the predictive value of high-sensitivity troponin I (hsTnI), both independently and in combination with N-terminal pro-B-type natriuretic peptide (NT-proBNP), for incident heart failure (HF) in high-risk hypertensive patients with preserved left ventricular ejection fraction (LVEF). Baseline hsTnI and NT-proBNP levels and echocardiography data were obtained for 493 Japanese hypertensive outpatients (mean age, 68.5 years) with LVEF ≥ 50%, no symptomatic HF, and at least one of the following comorbidities: stage 3-4 chronic kidney disease, diabetes mellitus, and stable coronary artery disease. During a mean follow-up period of 86.1 months, 44 HF admissions occurred, including 31 for HF with preserved ejection fraction (HFpEF) and 13 for HF with reduced ejection fraction (HFrEF; LVEF <50%). Both hsTnI (p < 0.01) and NT-proBNP (p < 0.005) levels were significant independent predictors of HF admission. Furthermore, when the patients were stratified into 4 groups according to increased hsTnI (≥highest tertile value of 10.6 pg/ml) and/or increased NT-proBNP (≥highest tertile value of 239.7 pg/ml), the adjusted relative risks for patients with increased levels of both biomarkers versus neither biomarker were 13.5 for HF admission (p < 0.0001), 9.45 for HFpEF (p = 0.0009), and 23.2 for HFrEF (p = 0.003). Finally, the combined use of hsTnI and NT-proBNP enhanced the C-index (p < 0.05), net reclassification improvement (p = 0.0001), and integrated discrimination improvement (p < 0.05) to a greater extent than that of any single biomarker. The combination of hsTnI and NT-proBNP, which are individually independently predictive of HF admission, could improve predictions of incident HF in high-risk hypertensive patients but could

  4. Steam generator tube failures

    SciTech Connect

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  5. Advanced Heart Failure

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Advanced Heart Failure Updated:Feb 9,2017 When heart failure (HF) ... content was last reviewed on 04/06/2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  6. Predicting Failure Initiation in Structural Adhesive Joints

    DTIC Science & Technology

    2012-08-15

    Elastoplástico de Adhesivos – Modeling, characterization and simulation of the elastoplastic behavior of adhesives. Maestría en Ciencia de Materiales...adhesive and a 1018 steel”. Maestría en Ciencia de Materiales. Centro de Investigación en Materiales Avanzados S.C. May 2012.  Abstract: In the

  7. Predicting vibrational failure of flexible ducting

    NASA Technical Reports Server (NTRS)

    Henry, R. H.

    1971-01-01

    Technique applies to liquid or gas transfer through flexible ducting and proves valuable in high velocity fluid flow cases. Fluid mechanism responsible for free bellows vibrational excitation also causes flexible hose oscillation. Static pressure stress influences flexible ducting fatigue life and is considered separately.

  8. Predicting Failure of Optical Glass Fibers.

    DTIC Science & Technology

    1981-10-01

    doped fused silica core with a borosilicate cladding but each had a different poly- mer coating. The three polymer coatings were polyene /polythiol...experiment. From these results it is believed that the polyene /- polythiol ester coating results in a significantly higher fatigue resistance and the...fatigue resistance of the polyene /polythiol ester coating (N=34) and the low fatigue resistance of the urethane acrylate coating (N=18) are thus consistent

  9. Anticipating Failures: What Should Predictions Be About?

    DTIC Science & Technology

    2001-01-01

    C., Luckas, W. J., Taylor, J. H. & Barriere, M. T. (1996). A technique Jbr human error analysis (ATHEANA) ( NUREG /CR-6350). Washington, DC: US Nuclear...trees/time reliability correlation ( NUREG /CR-3010). Washington, DC.: USNRC. Hollnagel, E. (1993a). Human reliability analysis: Context and control

  10. Failure analyses of composite bolted joints

    NASA Technical Reports Server (NTRS)

    Wilson, D. W.; Gillespie, J. W.; York, J. L.; Pipes, R. B.

    1980-01-01

    The complex failure behavior exhibited by bolted joints of graphite epoxy (Hercules AS/3501) was investigated for the net tension, bearing and shearout failure modes using combined analytical and experimental techniques. Plane stress, linear elastic, finite element methods were employed to determine the two dimensional state of stress resulting from a loaded hole in a finite width, semiinfinite strip. The stresses predicted by the finite element method were verified by experiment to lend credence to the analysis. The influence of joint geometric parameters on the state of stress and resultant strength of the joint was also studied. The resulting functional relationships found to exist between bolted joint strength and the geometric parameters, were applied in the formulation of semiempirical strength models for the basic failure modes. A point stress failure criterion was successfully applied as the failure criterion for the net tension and shearout failure modes.

  11. The lived experience of NCLEX failure.

    PubMed

    Griffiths, Margaret J; Papastrat, Karen; Czekanski, Kathleen; Hagan, Kevin

    2004-07-01

    Educators help coach, focus, and prepare students for the National Council Licensure Examination (NCLEX), but often fall short in providing support when graduates are not successful. Most research to date has focused solely on predicting failure, with little to no attention given to interventions after failure. This study presents the voices of unsuccessful candidates, their responses to failure, their perspectives of the factors that contributed to their failure, and the changes they made that led to subsequent success. The results demonstrate common themes related to the failure experience, successful remediation strategies for retesting, and recommendations for faculty interventions during this vulnerable period. Nurse educators have a responsibility to identify, inform, and intervene with students who are at high risk of failing the NCLEX, and this responsibility is executed capably. However, the role extends beyond graduation. The responsibility to help nursing graduates transition from failure to licensure is the final step of successful undergraduate nursing education.

  12. Failure analysis of high performance ballistic fibers

    NASA Astrophysics Data System (ADS)

    Spatola, Jennifer S.

    High performance fibers have a high tensile strength and modulus, good wear resistance, and a low density, making them ideal for applications in ballistic impact resistance, such as body armor. However, the observed ballistic performance of these fibers is much lower than the predicted values. Since the predictions assume only tensile stress failure, it is safe to assume that the stress state is affecting fiber performance. The purpose of this research was to determine if there are failure mode changes in the fiber fracture when transversely loaded by indenters of different shapes. An experimental design mimicking transverse impact was used to determine any such effects. Three different indenters were used: round, FSP, and razor blade. The indenter height was changed to change the angle of failure tested. Five high performance fibers were examined: KevlarRTM KM2, SpectraRTM 130d, DyneemaRTM SK-62 and SK-76, and ZylonRTM 555. Failed fibers were analyzed using an SEM to determine failure mechanisms. The results show that the round and razor blade indenters produced a constant failure strain, as well as failure mechanisms independent of testing angle. The FSP indenter produced a decrease in failure strain as the angle increased. Fibrillation was the dominant failure mechanism at all angles for the round indenter, while through thickness shearing was the failure mechanism for the razor blade. The FSP indenter showed a transition from fibrillation at low angles to through thickness shearing at high angles, indicating that the round and razor blade indenters are extreme cases of the FSP indenter. The failure mechanisms observed with the FSP indenter at various angles correlated with the experimental strain data obtained during fiber testing. This indicates that geometry of the indenter tip in compression is a contributing factor in lowering the failure strain of the high performance fibers. TEM analysis of the fiber failure mechanisms was also attempted, though without

  13. Using Statistical Penalties In The Tsai-Wu Failure Criterion

    NASA Technical Reports Server (NTRS)

    Richardson, D. E.; Regl, R. R.; Iverson, M. P.; Phipps, B. E.

    1996-01-01

    Improved methods of applying statistical penalties when using Tsai-Wu failure criterion lead to more accurate predictions of failures of composite-material structural components under stress, and provide better safety factors for designing such components. Intended to ensure proper use of statistical penalties with respect to failure hypersurface.

  14. Nonlinear Temperature Dependent Failure Analysis of Finite Width Composite Laminates.

    DTIC Science & Technology

    1979-12-01

    tangent modulii obtained by Ramberg-Osgood parameters. It is shown that a’ring stresses and stresses due to tensile loading are significant as edge ... effect in all types of laminate studies. The tensor polynomial failure criterion is used to predict the initiation of failure. The mode of failure is

  15. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints

    NASA Technical Reports Server (NTRS)

    Flom, Yory

    2011-01-01

    Interaction equations were proposed earlier to predict failure in Albemet 162 brazed joints. Present study demonstrates that the same interaction equations can be used for lower bound estimate of the failure criterion in 304 stainless steel joints brazed with silver-based filler metals as well as for construction of the Failure Assessment Diagrams (FAD).

  16. Evaluation of a Progressive Failure Analysis Methodology for Laminated Composite Structures

    NASA Technical Reports Server (NTRS)

    Sleight, David W.; Knight, Norman F., Jr.; Wang, John T.

    1997-01-01

    A progressive failure analysis methodology has been developed for predicting the nonlinear response and failure of laminated composite structures. The progressive failure analysis uses C plate and shell elements based on classical lamination theory to calculate the in-plane stresses. Several failure criteria, including the maximum strain criterion, Hashin's criterion, and Christensen's criterion, are used to predict the failure mechanisms. The progressive failure analysis model is implemented into a general purpose finite element code and can predict the damage and response of laminated composite structures from initial loading to final failure.

  17. Recognition Failure: Another Case of Retrieval Failure

    ERIC Educational Resources Information Center

    Rabinowitz, Jan; And Others

    1977-01-01

    A theoretical explanation of the phenomenon of recognition failure and a presentation of seven experiments investigating performance. Recognition failure is reduced when a more stringent recognition criterion is used, essentially eliminated when the proper access test is used and significantly reduced when variability in recognition performance is…

  18. Post Buckling Progressive Failure Analysis of Composite Laminated Stiffened Panels

    NASA Astrophysics Data System (ADS)

    Anyfantis, Konstantinos N.; Tsouvalis, Nicholas G.

    2012-06-01

    The present work deals with the numerical prediction of the post buckling progressive and final failure response of stiffened composite panels based on structural nonlinear finite element methods. For this purpose, a progressive failure model (PFM) is developed and applied to predict the behaviour of an experimentally tested blade-stiffened panel found in the literature. Failure initiation and propagation is calculated, owing to the accumulation of the intralaminar failure modes induced in fibre reinforced composite materials. Hashin failure criteria have been employed in order to address the fiber and matrix failure modes in compression and tension. On the other hand, the Tsai-Wu failure criterion has been utilized for addressing shear failure. Failure detection is followed with the introduction of corresponding material degradation rules depending on the individual failure mechanisms. Failure initiation and failure propagation as well as the post buckling ultimate attained load have been numerically evaluated. Final failure behaviour of the simulated stiffened panel is due to sudden global failure, as concluded from comparisons between numerical and experimental results being in good agreement.

  19. Progressive Failure Analysis of Composite Stiffened Panels

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Yarrington, Phillip W.; Collier, Craig S.; Arnold, Steven M.

    2006-01-01

    A new progressive failure analysis capability for stiffened composite panels has been developed based on the combination of the HyperSizer stiffened panel design/analysis/optimization software with the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC). MAC/GMC discretizes a composite material s microstructure into a number of subvolumes and solves for the stress and strain state in each while providing the homogenized composite properties as well. As a result, local failure criteria may be employed to predict local subvolume failure and the effects of these local failures on the overall composite response. When combined with HyperSizer, MAC/GMC is employed to represent the ply level composite material response within the laminates that constitute a stiffened panel. The effects of local subvolume failures can then be tracked as loading on the stiffened panel progresses. Sample progressive failure results are presented at both the composite laminate and the composite stiffened panel levels. Deformation and failure model predictions are compared with experimental data from the World Wide Failure Exercise for AS4/3501-6 graphite/epoxy laminates.

  20. Failure in glass

    NASA Technical Reports Server (NTRS)

    Keeton, S. C.

    1972-01-01

    Review of state of the art concerning glass failure mechanisms and fatigue theories discusses brittle fracture in glass, fatigue mechanisms, fatigue behavior, environmental effects on failure rate, and aging.

  1. [Understanding heart failure].

    PubMed

    Boo, José Fernando Guadalajara

    2006-01-01

    Heart failure is a disease with several definitions. The term "heart failure" is used by has brougth about confusion in the terminology. For this reason, the value of the ejection fraction (< 0.40 or < 0.35) is used in most meganalyses on the treatment of heart failure, avoiding the term "heart failure" that is a confounding concept. In this paper we carefully analyze the meaning of contractility, ventricular function or performance, preload, afterload, heart failure, compensation mechanisms in heart failure, myocardial oxygen consumption, inadequate, adequate and inappropriate hypertrophy, systole, diastole, compliance, problems of relaxation, and diastolic dysfunction. Their definitions are supported by the original scientific descriptions in an attempt to clarify the concepts about ventricular function and heart failure and, in this way, use the same scientific language about the meaning of ventricular function, heart failure, and diastolic dysfunction.

  2. Failures in psychodynamic psychotherapy.

    PubMed

    Gold, Jerry; Stricker, George

    2011-11-01

    This article addresses the issue of failures in psychodynamic psychotherapy. Drawing on the clinical and research literatures, and utilizing our clinical experiences, we first describe and define criteria for success and failure in treatment. We then review five factors that can lead to failure: client factors, therapist factors, technical factors, relationship factors, and environmental factors. We illustrate our presentation with a case example, and conclude by discussing ways in which the likelihood of failures in psychodynamic treatment can be lowered.

  3. Ammonia tank failure

    SciTech Connect

    Sweat, M.E.

    1983-04-01

    An ammonia tank failure at Hawkeye Chemical of Clinton, Iowa is discussed. The tank was a double-wall, 27,000 metric-ton tank built in 1968 and commissioned in December 1969. The paper presented covers the cause of the failure, repair, and procedural changes made to prevent recurrence of the failure. (JMT)

  4. Heart Failure: A Primer.

    PubMed

    Lee, Christopher S; Auld, Jonathan

    2015-12-01

    Heart failure is a complex and multisystem clinical syndrome that results from impaired ventricular contractility and/or relaxation. Hypertension, diabetes mellitus, and coronary artery disease are common antecedents to heart failure. The main pathogenic mechanisms involved in heart failure include sympathetic nervous and renin-angiotensin-aldosterone system activation, as well as inflammation. A detailed history and physical examination and additional diagnostic tests may be needed to diagnose heart failure. Most treatment strategies target neurohormonal systems. Nonpharmacologic interventions and effective engagement in self-care are also important in overall heart failure management. Therapeutic strategies are geared toward prolonging life and optimizing quality of life.

  5. Forecasting the failure of heterogeneous magmas

    NASA Astrophysics Data System (ADS)

    Vasseur, J.; Wadsworth, F. B.; Lavallée, Y.; Bell, A. F.; Main, I. G.; Dingwell, D. B.

    2015-12-01

    Eruption prediction is a long-sought-after goal of volcanology. Yet applying existing techniques retrospectively (hindcasting), we fail to predict events more often than we success. As much of the seismicity associated with intermediate to silicic volcanic eruptions comes from the brittle response of the ascending magma itself, we clearly require a good understanding of the parameters that control the ability to forecast magma failure itself. Here, we present suites of controlled experiments at magmatic temperatures using a range of synthetic magmas to investigate the control of microstructures on the efficacy of forecast models for material failure. We find that the failure of magmas with very little microstructural heterogeneity - such as melts - is very challenging to predict; whereas, the failure of very heterogeneous magmas is always well-predicted. To shed further light on this issue, we provide a scaling law based on the relationship between the microstructural heterogeneity in a magma and the error in the prediction of its failure time. We propose this method be used to elucidate the variable success rate of predicting volcanic predictions. We discuss this scaling in the context of the birth, life and death of structural heterogeneity during magma ascent with specific emphasis on obsidian-forming eruptions such as Chaitèn, 2008. During such eruptions, the repetitive creation and destruction of fractures filled with granular magma, which are thought to be the in situ remnants of seismogenic fracturing itself, are expressions of the life-cycle of heterogeneity in an otherwise coherent, melt-rich magma. We conclude that the next generation of failure forecast tools available to monitoring teams should incorporate some acknowledgment of the magma microstructure and not be solely based on the geophysical signals prior to eruption.

  6. Failure Assessment Diagram for Titanium Brazed Joints

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Jones, Justin S.; Powell, Mollie M.; Puckett, David F.

    2011-01-01

    The interaction equation was used to predict failure in Ti-4V-6Al joints brazed with Al 1100 filler metal. The joints used in this study were geometrically similar to the joints in the brazed beryllium metering structure considered for the ATLAS telescope. This study confirmed that the interaction equation R(sub sigma) + R(sub Tau) = 1, where R(sub sigma) and R(sub Tau)are normal and shear stress ratios, can be used as conservative lower bound estimate of the failure criterion in ATLAS brazed joints as well as for construction of the Failure Assessment Diagram (FAD).

  7. Kidney Failure: What to Expect

    MedlinePlus

    ... Kidneys & How They Work Kidney Disease A-Z Kidney Failure What is kidney failure and how is it treated? Kidney failure ... Methods for Kidney Failure: Peritoneal Dialysis . Peritoneal dialysis Kidney Transplant A kidney transplant places a healthy kidney ...

  8. Early complications. Respiratory failure.

    PubMed

    Zwischenberger, J B; Alpard, S K; Bidani, A

    1999-08-01

    Pulmonary complications following thoracic surgery are common and associated with significant morbidity and mortality. Respiratory failure after pneumonectomy occurs in approximately 5% to 15% of cases and significantly increases patient mortality. Strategies for ventilator support are based on the nature of the underlying complication and the pathophysiology of respiratory failure. This article describes the cause and pathophysiology of respiratory failure and pulmonary embolus postpneumonectomy. Diagnosis, management, and innovative therapies are also reviewed.

  9. On the failure indices of quadratic failure criteria for optimal stacking sequence design of laminated plate

    NASA Astrophysics Data System (ADS)

    Kim, C. W.; Song, S. R.; Hwang, W.; Park, H. C.; Han, K. S.

    1994-01-01

    The quadratic failure criterion, which is intended to predict fracture, may be used as an object function for optimal stacking sequence design of laminated plate. However, calculations using a symmetric laminated plate demonstrate that Tsai-Wu theory may give incorrect optimum predictions under uniaxial loading.

  10. Failure to thrive.

    PubMed

    Krugman, Scott D; Dubowitz, Howard

    2003-09-01

    Failure to thrive is a condition commonly seen by primary care physicians. Prompt diagnosis and intervention are important for preventing malnutrition and developmental sequelae. Medical and social factors often contribute to failure to thrive. Either extreme of parental attention (neglect or hypervigilance) can lead to failure to thrive. About 25 percent of normal infants will shift to a lower growth percentile in the first two years of life and then follow that percentile; this should not be diagnosed as failure to thrive. Infants with Down syndrome, intrauterine growth retardation, or premature birth follow different growth patterns than normal infants. Many infants with failure to thrive are not identified unless careful attention is paid to plotting growth parameters at routine checkups. A thorough history is the best guide to establishing the etiology of the failure to thrive and directing further evaluation and management. All children with failure to thrive need additional calories for catch-up growth (typically 150 percent of the caloric requirement for their expected, not actual, weight). Few need laboratory evaluation. Hospitalization is rarely required and is indicated only for severe failure to thrive and for those whose safety is a concern. A multidisciplinary approach is recommended when failure to thrive persists despite intervention or when it is severe.

  11. The Predictable Failure of Educational Reform: Can We Change Course before It's Too Late? The Jossey-Bass Education Series and the Jossey-Bass Social and Behavioral Science Series.

    ERIC Educational Resources Information Center

    Sarason, Seymour B.

    Schools have been intractable to change and the attainment of goals set by reformers. A major failure has been the inability of reformers to confront this intractability. As a result, each new wave of reform learns nothing from earlier efforts and comes up with recommendations that have failed in the past. Nine chapters explore why reform efforts…

  12. Failure to Achieve a PSA Level {<=}1 ng/mL After Neoadjuvant LHRHA Therapy Predicts for Lower Biochemical Control Rate and Overall Survival in Localized Prostate Cancer Treated With Radiotherapy

    SciTech Connect

    Mitchell, Darren M. McAleese, Jonathan; Park, Richard M.; Stewart, David P.; Stranex, Stephen; Eakin, Ruth L.; Houston, Russell F.; O'Sullivan, Joe M.

    2007-12-01

    Purpose: To investigate whether failure to suppress the prostate-specific antigen (PSA) level to {<=}1 ng/mL after {>=}2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy in patients scheduled to undergo external beam radiotherapy for localized prostate carcinoma is associated with reduced biochemical failure-free survival. Methods and Materials: A retrospective case note review of consecutive patients with intermediate- or high-risk localized prostate cancer treated between January 2001 and December 2002 with neoadjuvant hormonal deprivation therapy, followed by concurrent hormonal therapy and radiotherapy was performed. Patient data were divided for analysis according to whether the PSA level in Week 1 of radiotherapy was {<=}1.0 ng/mL. Biochemical failure was determined using the American Society for Therapeutic Radiology and Oncology (Phoenix) definition. Results: A total of 119 patients were identified. The PSA level after neoadjuvant hormonal deprivation therapy was {<=}1 ng/mL in 67 patients and >1 ng/mL in 52. At a median follow-up of 49 months, the 4-year actuarial biochemical failure-free survival rate was 84% vs. 60% (p = 0.0016) in favor of the patients with a PSA level after neoadjuvant hormonal deprivation therapy of {<=}1 ng/mL. The overall survival rate was 94% vs. 77.5% (p = 0.0045), and the disease-specific survival rate at 4 years was 98.5% vs. 82.5%. Conclusions: The results of our study have shown that patients with a PSA level >1 ng/mL at the beginning of external beam radiotherapy after {>=}2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy have a significantly greater rate of biochemical failure and lower survival rate compared with those with a PSA level of {<=}1 ng/mL. Patients without adequate PSA suppression should be considered a higher risk group and considered for dose escalation or the use of novel treatments.

  13. Experience with renal failure during extracorporeal membrane oxygenation: treatment with continuous hemofiltration.

    PubMed

    Sell, L L; Cullen, M L; Whittlesey, G C; Lerner, G R; Klein, M D

    1987-07-01

    We use extracorporeal membrane oxygenation (ECMO) to treat respiratory and cardiac failure in children who are unresponsive to standard ventilator and pharmacologic management. All patients have cardiac and abdominal ultrasonography prior to ECMO to identify major structural anomalies and anatomically normal kidneys. Despite this, oliguric renal failure is seen in a number of patients. Acute renal failure (ARF) developed in two of the first 20 patients we placed on ECMO and both of these patients died. Six of the last 27 patients (22%) also developed ARF and were treated with continuous hemofiltration (CH) placed in-line with the extracorporeal circuit. The technique of CH removes plasma water and dissolved solutes while retaining proteins and cellular components of the intravascular space. The duration of CH ranged from 9 to 112 hours (mean 57.5 hours). Indications for CH were hypervolemia, hyperkalemia, and azotemia. The mean serum potassium prior to CH was 5.6 (range 4.3 to 7.0) compared with 4.5 after filtration. We filtered 5 to 10 mL/kg/h and replaced it with crystalloid chosen on the basis of serum and filtrate electrolytes. These six patients had a 33% mean weight gain prior to CH. We were able to remove as much as 2,200 g in the most edematous patient with significant improvement in cardiopulmonary status. Four of the patients on CH died of their primary pulmonary or cardiac disease without specific problems related to ARF. The other two patients were successfully weaned from ECMO, extubated, and have not needed further therapy for renal failure. We conclude that CH is useful in managing the complications of oliguric renal failure during ECMO.

  14. Heterogeneity: The key to failure forecasting

    PubMed Central

    Vasseur, Jérémie; Wadsworth, Fabian B.; Lavallée, Yan; Bell, Andrew F.; Main, Ian G.; Dingwell, Donald B.

    2015-01-01

    Elastic waves are generated when brittle materials are subjected to increasing strain. Their number and energy increase non-linearly, ending in a system-sized catastrophic failure event. Accelerating rates of geophysical signals (e.g., seismicity and deformation) preceding large-scale dynamic failure can serve as proxies for damage accumulation in the Failure Forecast Method (FFM). Here we test the hypothesis that the style and mechanisms of deformation, and the accuracy of the FFM, are both tightly controlled by the degree of microstructural heterogeneity of the material under stress. We generate a suite of synthetic samples with variable heterogeneity, controlled by the gas volume fraction. We experimentally demonstrate that the accuracy of failure prediction increases drastically with the degree of material heterogeneity. These results have significant implications in a broad range of material-based disciplines for which failure forecasting is of central importance. In particular, the FFM has been used with only variable success to forecast failure scenarios both in the field (volcanic eruptions and landslides) and in the laboratory (rock and magma failure). Our results show that this variability may be explained, and the reliability and accuracy of forecast quantified significantly improved, by accounting for material heterogeneity as a first-order control on forecasting power. PMID:26307196

  15. Mechanical failure of cavities in poroelastic media

    SciTech Connect

    Ozkan, G.; Ortoleva, P.

    1998-12-31

    The stress-induced failure of cavities in poroelastic media is investigated using an analytical solution of the elastic matrix inclusion problem of Eshelby and a rock failure criterion. The elastic properties of the porous matrix surrounding the cavity are modeled using a self-consistent version of the theory of Berryman while the cavity collapse criterion is based on a failure condition calibrated as a function of matrix mineralogy, grain size and porosity. The influence of the latter textural variables as well as pore fluid pressure and cavity shape and orientation relative to the far-field stress are evaluated. The region of failure on the cavity surface is identified. These results are applied to the prediction of vug stability in a sedimentary basin in the context of vuggy reservoir exploration and production.

  16. Living with Respiratory Failure

    MedlinePlus

    ... smoking. Emotional Issues and Support Living with respiratory failure may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can ... to living with respiratory failure. You can see how other people who have ...

  17. 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.

  18. Compression failure of angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Peel, Larry D.; Hyer, Michael W.; Shuart, Mark J.

    1991-01-01

    The present work deals with modes and mechanisms of failure in compression of angle-ply laminates. Experimental results were obtained from 42 angle-ply IM7/8551-7a specimens with a lay-up of ((plus or minus theta)/(plus or minus theta)) sub 6s where theta, the off-axis angle, ranged from 0 degrees to 90 degrees. The results showed four failure modes, these modes being a function of off-axis angle. Failure modes include fiber compression, inplane transverse tension, inplane shear, and inplane transverse compression. Excessive interlaminar shear strain was also considered as an important mode of failure. At low off-axis angles, experimentally observed values were considerably lower than published strengths. It was determined that laminate imperfections in the form of layer waviness could be a major factor in reducing compression strength. Previously developed linear buckling and geometrically nonlinear theories were used, with modifications and enhancements, to examine the influence of layer waviness on compression response. The wavy layer is described by a wave amplitude and a wave length. Linear elastic stress-strain response is assumed. The geometrically nonlinear theory, in conjunction with the maximum stress failure criterion, was used to predict compression failure and failure modes for the angle-ply laminates. A range of wave length and amplitudes were used. It was found that for 0 less than or equal to theta less than or equal to 15 degrees failure was most likely due to fiber compression. For 15 degrees less than theta less than or equal to 35 degrees, failure was most likely due to inplane transverse tension. For 35 degrees less than theta less than or equal to 70 degrees, failure was most likely due to inplane shear. For theta less than 70 degrees, failure was most likely due to inplane transverse compression. The fiber compression and transverse tension failure modes depended more heavily on wave length than on wave amplitude. Thus using a single

  19. Micromechanics-Based Progressive Failure Analysis of Composite Laminates Using Different Constituent Failure Theories

    NASA Technical Reports Server (NTRS)

    Moncada, Albert M.; Chattopadhyay, Aditi; Bednarcyk, Brett A.; Arnold, Steven M.

    2008-01-01

    Predicting failure in a composite can be done with ply level mechanisms and/or micro level mechanisms. This paper uses the Generalized Method of Cells and High-Fidelity Generalized Method of Cells micromechanics theories, coupled with classical lamination theory, as implemented within NASA's Micromechanics Analysis Code with Generalized Method of Cells. The code is able to implement different failure theories on the level of both the fiber and the matrix constituents within a laminate. A comparison is made among maximum stress, maximum strain, Tsai-Hill, and Tsai-Wu failure theories. To verify the failure theories the Worldwide Failure Exercise (WWFE) experiments have been used. The WWFE is a comprehensive study that covers a wide range of polymer matrix composite laminates. The numerical results indicate good correlation with the experimental results for most of the composite layups, but also point to the need for more accurate resin damage progression models.

  20. Acute Decompensated Heart Failure

    PubMed Central

    Joseph, Susan M.; Cedars, Ari M.; Ewald, Gregory A.; Geltman, Edward M.; Mann, Douglas L.

    2009-01-01

    Hospitalizations for acute decompensated heart failure are increasing in the United States. Moreover, the prevalence of heart failure is increasing consequent to an increased number of older individuals, as well as to improvement in therapies for coronary artery disease and sudden cardiac death that have enabled patients to live longer with cardiovascular disease. The main treatment goals in the hospitalized patient with heart failure are to restore euvolemia and to minimize adverse events. Common in-hospital treatments include intravenous diuretics, vasodilators, and inotropic agents. Novel pharmaceutical agents have shown promise in the treatment of acute decompensated heart failure and may simplify the treatment and reduce the morbidity associated with the disease. This review summarizes the contemporary management of patients with acute decompensated heart failure. PMID:20069075

  1. Heart Failure Epidemiology: European Perspective

    PubMed Central

    Guha, K; McDonagh, T

    2013-01-01

    Heart failure poses an increasing problem for global healthcare systems. The epidemiological data which has been accrued over the last thirty years has predominantly been accumulated from experience within North America and Europe. Initial large cohort, prospective longitudinal studies produced the first publications; however latterly the focus has shifted onto epidemiological data governing hospitalisation and mortality. The emphasis behind this shift has been the resource implications with regards to repetitive, costly and prolonged hospitalisation. The European experience in heart failure, though similar to North America has recently demonstrated differences in hospitalisation which may underlie the differences between healthcare system configuration. Heart failure however remains an increasing global problem and the endpoint of a variety of cardiovascular diseases. Allied with the fact of increasingly elderly populations and prior data demonstrating a steep rise in prevalent cases within more elderly populations, it is likely that the increasing burden of disease will continue to pose challenges for modern healthcare. Despite the predicted increase in the number of patients affected by heart failure, over the last thirty years, a clear management algorithm has evolved for the use of pharmacotherapies (neuro-hormonal antagonists), device based therapies (Implantable Cardioverting Defibrillator (ICD) and Cardiac Resynchronisation Therapy (CRT)) and mechanical therapies including left ventricular assist devices and cardiac transplantation. Though the management of such patients has been clearly delineated in national and international guidelines, the underuse of all available and appropriate therapies remains a significant problem. When comparing various epidemiological studies from different settings and timepoints, it should be remembered that rates of prevalence and incidence may vary depending upon the definition used, methods of accumulating information (with

  2. Failure of underground concrete structures subjected to blast loadings

    NASA Technical Reports Server (NTRS)

    Ross, C. A.; Nash, P. T.; Griner, G. R.

    1979-01-01

    The response and failure of two edges of free reinforced concrete slabs subjected to intermediate blast loadings are examined. The failure of the reinforced concrete structures is defined as a condition where actual separation or fracture of the reinforcing elements has occurred. Approximate theoretical methods using stationary and moving plastic hinge mechanisms with linearly varying and time dependent loadings are developed. Equations developed to predict deflection and failure of reinforced concrete beams are presented and compared with the experimental results.

  3. Buckling failures in insect exoskeletons.

    PubMed

    Parle, Eoin; Herbaj, Simona; Sheils, Fiona; Larmon, Hannah; Taylor, David

    2015-12-17

    Thin walled tubes are often used for load-bearing structures, in nature and in engineering, because they offer good resistance to bending and torsion at relatively low weight. However, when loaded in bending they are prone to failure by buckling. It is difficult to predict the loading conditions which cause buckling, especially for tubes whose cross sections are not simple shapes. Insights into buckling prevention might be gained by studying this phenomenon in the exoskeletons of insects and other arthropods. We investigated the leg segments (tibiae) of five different insects: the locust (Schistocerca gergaria), American cockroach (Periplaneta americana), death's head cockroach (Blaberus discoidalis), stick insect (Parapachymorpha zomproi) and bumblebee (Bombus terrestris audax). These were tested to failure in cantilever bending and modelled using finite element analysis (FEA). The tibiae of the locust and the cockroaches were found to be approximately circular in shape. Their buckling loads were well predicted by linear elastic FEA, and also by one of the analytical solutions available in the literature for elastic buckling. The legs of the stick insect are also circular in cross section but have several prominent longitudinal ridges. We hypothesised that these ridges might protect the legs against buckling but we found that this was not the case: the loads necessary for elastic buckling were not reached in practice because yield occurred in the material, causing plastic buckling. The legs of bees have a non-circular cross section due to a pollen-carrying feature (the corbicula). We found that this did not significantly affect their resistance to buckling. Our results imply that buckling is the dominant failure mode in the tibia of insects; it likely to be a significant consideration for other arthropods and any organisms with stiff exoskeletons. The interactions displayed here between material properties and cross sectional geometry may provide insights for the

  4. [Heart failure and comorbidities].

    PubMed

    Boully, Clémence; Hanon, Olivier

    2015-03-01

    Heart failure is a frequent disease in the elderly. Its clinical presentation is less typical and the prognosis more severe than in younger subjects because heart failure occurs in patients with multiple comorbidities. A comprehensive geriatric assessment should therefore be performed to detect the vulnerabilities and manage the comorbidities. The main diseases associated with heart failure are dementia, depression, malnutrition, atrial fibrillation, coronary artery disease, orthostatic hypotension, renal failure, anemia and iron deficiency. Comorbidities worsen heart failure and makes its treatment more difficult. The identification and treatment of comorbidities improve the prognosis in terms of mortality but especially in terms of quality of life. Caution with drugs is necessary because of pharmacokinetic or pharmacodynamic changes related to aging and the comorbidities. In this context, clinical and laboratory monitoring should be increased, mostly during an acute event (acute heart failure, infection, dehydration, fall, new therapy…). Therefore, the follow-up of elderly patients with heart failure requires a multidisciplinary approach that involves close cooperation between cardiologists, geriatricians, general practitioners, nurses, and pharmacists.

  5. A physically based failure criterion for laminated composites

    NASA Astrophysics Data System (ADS)

    Kroll, L.; Hufenbach, W.

    1999-07-01

    The stress and strain fields in laminated composites can be described realistically with the help of a refined theory of elasticity for anisotropic materials. In contrast, the respective failure characteristics cannot be predicted satisfactorily based on the commonly used failure criteria. The main disadvantage of these generalized failure criteria, such as the quadratic failure criteria of Sakharov, Azzi/Tsai, Tsai/Wu, etc., is that they combine fundamentally different fracture mechanisms of the homogenized UD layer in one approximation by an interpolation polynomial. A completely different method for the formulation of realistic failure criteria, taking into account the heterogeneous anisotropic material structure relevant to the fracture, is based on the Mohr hypothesis for brittle materials that in fact only the stresses in the fracture plane induce failure. This physically based failure criterion not only considers the decisive eifference between the fiber fracture and the interfiber fracture, but also characterizes further fracture types in the plane parallel to the fibers.

  6. Liver Failure in Pregnancy.

    PubMed

    Bacak, Stephen J; Thornburg, Loralei L

    2016-01-01

    Acute liver failure is a rare but life-threatening medical emergency in pregnancy whose true incidence remains unknown. Many cases of acute liver failure are caused by pregnancy-related conditions such as acute fatty liver of pregnancy and HELLP syndrome. However, acute deterioration in liver function can also be caused by drug overdose, viral infections, and an exacerbation of underlying chronic liver disease. This article provides an overview of the normal liver changes that occur during pregnancy, and summarizes the most common conditions and general management strategies of liver failure during pregnancy.

  7. Damage mechanics - failure modes

    SciTech Connect

    Krajcinovic, D.; Vujosevic, M.

    1996-12-31

    The present study summarizes the results of the DOE sponsored research program focused on the brittle failure of solids with disordered microstructure. The failure is related to the stochastic processes on the microstructural scale; namely, the nucleation and growth of microcracks. The intrinsic failure modes, such as the percolation, localization and creep rupture, are studied by emphasizing the effect of the micro-structural disorder. A rich spectrum of physical phenomena and new concepts that emerges from this research demonstrates the reasons behind the limitations of traditional, deterministic, and local continuum models.

  8. Heart failure - discharge

    MedlinePlus

    ... Heart failure - overview Heart pacemaker High blood pressure Implantable cardioverter-defibrillator Smoking - tips on how to quit ... ask your doctor How to read food labels Implantable cardioverter defibrillator - discharge Low-salt diet Mediterranean diet ...

  9. Heart failure overview

    MedlinePlus

    ... heart failure: Fast or difficult breathing Leg swelling (edema) Neck veins that stick out (are distended) Sounds ( ... pacemaker High blood pressure Implantable cardioverter-defibrillator Pulmonary edema Stable angina Ventricular assist device Patient Instructions ACE ...

  10. Failure to communicate.

    PubMed

    Fiesta, J

    1998-02-01

    When a medication error is coupled with a communication problem, a patient may experience significant injury. Cases involving communication breakdown, i.e, failure to communicate or listen, are discussed.

  11. Triac failure detector

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A failure detector is provided for detecting unidirectional failures in triacs, particularly as used in power factor controllers for induction motors. In a first embodiment, the triac voltage waveform is sensed and upon detection of an unbalanced signal, corresponding to failure of the triac in either the positive or negative direction, the triac is turned full on in both directions. In a second embodiment, a pair of pulsed signals are derived, the pulse durations of which are proportional to the phase difference between the load current and voltage for each half cycle, and the triac is turned full on responsive to a difference in pulse duration between the half cycle signals. An unidirectional open circuit detector is adapted to use a signal from either of the first and second embodiment to turn the triac off in response to an open circuit failure in either direction.

  12. Inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  13. Heart failure - tests

    MedlinePlus

    CHF - tests; Congestive heart failure - tests; Cardiomyopathy - tests; HF - tests ... An echocardiogram (Echo) is a test that uses sound waves to create a moving picture of the heart. The picture is much more detailed than a plain ...

  14. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Robert; Novack, Steven

    2015-01-01

    Space Launch System (SLS) Agenda: Objective; Key Definitions; Calculating Common Cause; Examples; Defense against Common Cause; Impact of varied Common Cause Failure (CCF) and abortability; Response Surface for various CCF Beta; Takeaways.

  15. Evaluation of ultrafiltration failure.

    PubMed

    Korbet, S M

    1998-07-01

    The evaluation of ultrafiltration failure is embarked upon when a patient has persistent problems with symptoms and signs of fluid overload. Fluid overload is a common problem in peritoneal dialysis (PD) patients and the risk of its occurrence increases with time on dialysis. Although often attributed to changes in peritoneal membrane function (membrane failure), there are a number of potential, and frequently more common factors that can contribute to the failure of adequate fluid removal in patients on PD. Many of the causes of ultrafiltration failure may be apparent after an initial informal evaluation. However, if after this the etiology remains unexplained, a systematic approach to the differential diagnosis of this problem can be utilized with the use of the peritoneal equilibration test. Once a diagnosis is confirmed, a logical therapeutic plan can be formulated.

  16. Living with Heart Failure

    MedlinePlus

    ... help you in the future. Follow Your Treatment Plan Treatment can relieve your symptoms and make daily ... or nurse about getting flu and pneumonia vaccines. Plan Ahead If you have heart failure, it's important ...

  17. What Causes Respiratory Failure?

    MedlinePlus

    ... Conditions Causing Respiratory Failure Figure A shows the location of the lungs, airways, diaphragm, rib cage, pulmonary arteries, brain, and spinal cord ... STATEMENT FOIA NO FEAR ACT OIG CONTACT US ...

  18. Genesis Failure Investigation Report

    NASA Technical Reports Server (NTRS)

    Klein, John

    2004-01-01

    The-Genesis mission to collect solar-wind samples and return them to Earth for detailed analysis proceeded successfully for 3.5 years. During reentry on September 8, 2004, a failure in the entry, descent and landing sequence resulted in a crash landing of the Genesis sample return capsule. This document describes the findings of the avionics sub-team that supported the accident investigation of the JPL Failure Review Board.

  19. Heart failure in pregnancy.

    PubMed

    Rutherford, John D

    2012-12-01

    With increasing maternal age and the presence of comorbid conditions such as hypertension, cardiovascular assessment and monitoring is the responsibility of all clinicians caring for pregnant patients. Furthermore, there are specific conditions, such as mitral stenosis, peripartum cardiomyopathy, and preeclampsia, that can be associated with heart failure and secondary maternal (and fetal) mortality and morbidity. The important causes of heart failure in pregnancy are discussed.

  20. Acute renal failure.

    PubMed

    Bellomo, Rinaldo

    2011-10-01

    Acute renal failure (now acute kidney injury) is a common complication of critical illness affecting between 30 and 60% of critically ill patients. The development of a consensus definition (RIFLE--risk, injury, failure, loss, end-stage system) has allowed standardization of reporting and epidemiological work. Multicenter multinational epidemiological studies indicate that sepsis is now the most common cause of acute renal failure in the intensive care unit (ICU) followed by cardiac surgery-associated acute kidney injury. Unfortunately, our understanding of the pathogenesis of acute renal failure in these settings remains limited. Because of such limited understanding, no reproducibly effective therapies have been developed. In addition the diagnosis of acute renal failure still rests upon the detection of changes in serum creatinine, which only occur if more than 50% of glomerular filtration is lost and are often delayed by more than 24 hours. Such diagnostic delays make the implementation of early therapy nearly impossible. In response to these difficulties, there has been a concerted effort to use proteomics to identify novel early biomarkers of acute renal failure. The identification and study of neutrophil gelatinase- associated lipocalin has been an important step in this field. Another area of active interest and investigation relates to the role of intravenous fluid resuscitation and fluid balance. Data from large observational studies and randomized, controlled trials consistently indicate that a positive fluid balance in patients with acute renal failure represents a major independent risk factor for mortality and provides no protection of renal function. The pendulum is clearly swinging away from a fluid-liberal approach to a fluid-conservative approach in these patients. Finally, there is a growing appreciation that acute renal failure may identify patients who are at increased risk of subsequent chronic renal dysfunction and mortality, opening the way

  1. Mechanistic fracture criteria for the failure of human cortical bone

    SciTech Connect

    Nalla, Ravi K.; Kinney, John H.; Ritchie, Robert O.

    2002-12-13

    A mechanistic understanding of fracture in human bone is critical to predicting fracture risk associated with age and disease. Despite extensive work, a mechanistic framework for describing how the underlying microstructure affects the failure mode in bone is lacking.

  2. On the failure and post-failure of fiber composites in compression

    NASA Astrophysics Data System (ADS)

    Vogler, Tracy John

    The failure and post-failure behavior of an AS4/PEEK composite in axial compression was studied through experiments and analysis. Compressive stresses cause shearing of the matrix in regions of fiber misaligned. Increasing stresses yield the matrix, resulting in fiber collapse and failure of the composite. The strength is strongly imperfection sensitive. After failure, deformation localizes into an inclined region of rotated fibers called a kink band. Compressive failure was investigated using 2-D and 3-D finite element models and three simpler models. When properly calibrated, their strength predictions are quite similar, especially for larger fiber misalignments. However, the FE models allow examination of post-failure events leading to kink band formation. The rate dependence of compressive strength was examined experimentally and with a modified version of a simple model. The addition of a far-field shear stress significantly reduces the compressive strength. Failure predictions from modified versions of the 2-D model and the simple models agree well with experimental data. Post-failure events are very similar to those observed for pure compression loading, except that failure can occur in a controlled manner for certain loading paths. It has been discovered that the kink bands formed during compressive failure can propagate axially in a steady-state manner at a constant stress level termed the propagation stress. This propagation stress, a new characteristic stress of the material, is approximately 40% of the compressive strength for AS4/PEEK. Steadystate propagation can give "ductility" to a material normally considered quite brittle. The propagation has been observed directly, revealing the mechanism of propagation as well as new details about fiber rotation in the band. A 3-D numerical model was developed which simulates the steady-state propagation. The propagation stress and deformation are predicted reasonably well. As a basis for modeling of failure and

  3. Failure Criteria for FRP Laminates in Plane Stress

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.; Camanho, Pedro P.

    2003-01-01

    A new set of six failure criteria for fiber reinforced polymer laminates is described. Derived from Dvorak's fracture mechanics analyses of cracked plies and from Puck's action plane concept, the physically-based criteria, denoted LaRC03, predict matrix and fiber failure accurately without requiring curve-fitting parameters. For matrix failure under transverse compression, the fracture plane is calculated by maximizing the Mohr-Coulomb effective stresses. A criterion for fiber kinking is obtained by calculating the fiber misalignment under load, and applying the matrix failure criterion in the coordinate frame of the misalignment. Fracture mechanics models of matrix cracks are used to develop a criterion for matrix in tension and to calculate the associated in-situ strengths. The LaRC03 criteria are applied to a few examples to predict failure load envelopes and to predict the failure mode for each region of the envelope. The analysis results are compared to the predictions using other available failure criteria and with experimental results. Predictions obtained with LaRC03 correlate well with the experimental results.

  4. Decompensated heart failure

    PubMed Central

    Mangini, Sandrigo; Pires, Philippe Vieira; Braga, Fabiana Goulart Marcondes; Bacal, Fernando

    2013-01-01

    ABSTRACT Heart failure is a disease with high incidence and prevalence in the population. The costs with hospitalization for decompensated heart failure reach approximately 60% of the total cost with heart failure treatment, and mortality during hospitalization varies according to the studied population, and could achieve values of 10%. In patients with decompensated heart failure, history and physical examination are of great value for the diagnosis of the syndrome, and also can help the physician to identify the beginning of symptoms, and give information about etiology, causes and prognosis of the disease. The initial objective of decompensated heart failure treatment is the hemodynamic and symptomatic improvement preservation and/or improvement of renal function, prevention of myocardial damage, modulation of the neurohormonal and/or inflammatory activation and control of comorbidities that can cause or contribute to progression of the syndrome. According to the clinical-hemodynamic profile, it is possible to establish a rational for the treatment of decompensated heart failure, individualizing the proceedings to be held, leading to reduction in the period of hospitalization and consequently reducing overall mortality. PMID:24136770

  5. Premature ovarian failure.

    PubMed

    Kalantaridou, S N; Davis, S R; Nelson, L M

    1998-12-01

    In 1% of women, premature ovarian failure develops by 40 years of age, a condition causing amenorrhea, infertility, sex steroid deficiency, and elevated gonadotropins. Early loss of ovarian function has significant psychosocial sequelae and major health implications. These young women have a nearly two-fold age-specific increase in mortality rate. Among women with spontaneous premature ovarian failure who have a normal karyotype, half have ovarian follicles remaining in the ovary that function intermittently. Indeed, pregnancies have occurred after the diagnosis of premature ovarian failure. Thus, premature ovarian failure should not be considered as a premature menopause. Young women with this disorder have a 5% to 10% chance for spontaneous pregnancy. Attempts at ovulation induction using various regimens fail to induce ovulation rates greater than those seen in untreated patients; however, oocyte donation for women desiring fertility is an option. Young women with premature ovarian failure need a thorough assessment, sex steroid replacement, and long-term surveillance to monitor therapy. Estrogen-progestin replacement therapy should be instituted as soon as the diagnosis is made. Androgen replacement should also be considered for women with low libido, persistent fatigue, and poor well-being despite taking adequate estrogen replacement. Women with premature ovarian failure should be followed up for the presence of associated autoimmune endocrine disorders such as hypothyroidism, adrenal insufficiency, and diabetes mellitus.

  6. Robustness of network controllability in cascading failure

    NASA Astrophysics Data System (ADS)

    Chen, Shi-Ming; Xu, Yun-Fei; Nie, Sen

    2017-04-01

    It is demonstrated that controlling complex networks in practice needs more inputs than that predicted by the structural controllability framework. Besides, considering the networks usually faces to the external or internal failure, we define parameters to evaluate the control cost and the variation of controllability after cascades, exploring the effect of number of control inputs on the controllability for random networks and scale-free networks in the process of cascading failure. For different topological networks, the results show that the robustness of controllability will be stronger through allocating different control inputs and edge capacity.

  7. Basic failure mechanisms in advanced composites

    NASA Technical Reports Server (NTRS)

    Mullin, J. V.; Mazzio, V. F.; Mehan, R. L.

    1972-01-01

    Failure mechanisms in carbon-epoxy composites are identified as a basis for more reliable prediction of the performance of these materials. The approach involves both the study of local fracture events in model specimens containing small groups of filaments and fractographic examination of high fiber content engineering composites. Emphasis is placed on the correlation of model specimen observations with gross fracture modes. The effects of fiber surface treatment, resin modification and fiber content are studied and acoustic emission methods are applied. Some effort is devoted to analysis of the failure process in composite/metal specimens.

  8. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Rob; Novack, Steven D.

    2015-01-01

    Common Cause Failures (CCFs) are a known and documented phenomenon that defeats system redundancy. CCFS are a set of dependent type of failures that can be caused by: system environments; manufacturing; transportation; storage; maintenance; and assembly, as examples. Since there are many factors that contribute to CCFs, the effects can be reduced, but they are difficult to eliminate entirely. Furthermore, failure databases sometimes fail to differentiate between independent and CCF (dependent) failure and data is limited, especially for launch vehicles. The Probabilistic Risk Assessment (PRA) of NASA's Safety and Mission Assurance Directorate at Marshall Space Flight Center (MFSC) is using generic data from the Nuclear Regulatory Commission's database of common cause failures at nuclear power plants to estimate CCF due to the lack of a more appropriate data source. There remains uncertainty in the actual magnitude of the common cause risk estimates for different systems at this stage of the design. Given the limited data about launch vehicle CCF and that launch vehicles are a highly redundant system by design, it is important to make design decisions to account for a range of values for independent and CCFs. When investigating the design of the one-out-of-two component redundant system for launch vehicles, a response surface was constructed to represent the impact of the independent failure rate versus a common cause beta factor effect on a system's failure probability. This presentation will define a CCF and review estimation calculations. It gives a summary of reduction methodologies and a review of examples of historical CCFs. Finally, it presents the response surface and discusses the results of the different CCFs on the reliability of a one-out-of-two system.

  9. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Rob; Novack, Steven D.

    2016-01-01

    Common Cause Failures (CCFs) are a known and documented phenomenon that defeats system redundancy. CCFS are a set of dependent type of failures that can be caused by: system environments; manufacturing; transportation; storage; maintenance; and assembly, as examples. Since there are many factors that contribute to CCFs, the effects can be reduced, but they are difficult to eliminate entirely. Furthermore, failure databases sometimes fail to differentiate between independent and CCF (dependent) failure and data is limited, especially for launch vehicles. The Probabilistic Risk Assessment (PRA) of NASA's Safety and Mission Assurance Directorate at Marshal Space Flight Center (MFSC) is using generic data from the Nuclear Regulatory Commission's database of common cause failures at nuclear power plants to estimate CCF due to the lack of a more appropriate data source. There remains uncertainty in the actual magnitude of the common cause risk estimates for different systems at this stage of the design. Given the limited data about launch vehicle CCF and that launch vehicles are a highly redundant system by design, it is important to make design decisions to account for a range of values for independent and CCFs. When investigating the design of the one-out-of-two component redundant system for launch vehicles, a response surface was constructed to represent the impact of the independent failure rate versus a common cause beta factor effect on a system's failure probability. This presentation will define a CCF and review estimation calculations. It gives a summary of reduction methodologies and a review of examples of historical CCFs. Finally, it presents the response surface and discusses the results of the different CCFs on the reliability of a one-out-of-two system.

  10. A Comparison of the Haider Tube-Guard® Endotracheal Tube Holder Versus Adhesive Tape to Determine if This Novel Device Can Reduce Endotracheal Tube Movement and Prevent Unplanned Extubation

    PubMed Central

    Buckley, Jack C.; Brown, Adam P.; Shin, John S.; Rogers, Kirsten M.

    2016-01-01

    a high extubation risk (endotracheal tube movement >4 cm) when the endotracheal tube was secured with tape versus 0% (0/30) when secured with the Haider Tube-Guard (P = 0.004). Six patients with taped endotracheal tubes required the traction to be aborted before 15 N of force was achieved to prevent potential extubation as the tape either separated from the face or stretched to allow excessive endotracheal tube movement. None of the patients appeared to sustain any injury from the Haider Tube-Guard device. CONCLUSIONS: The Haider Tube-Guard significantly reduced the mobility of the endotracheal tube when compared with adhesive tape and was well tolerated in our observations. PMID:26983051

  11. Static strength and failure mechanism of CFRP under biaxial loadings

    NASA Astrophysics Data System (ADS)

    Lee, C. S.; Hwang, W.; Park, H. C.; Han, K. S.

    1998-01-01

    Tests of cross-ply composite tubes were performed under combined axial and torsional loading up to failure. Strength properties and failure mechanisms were evaluated with reference to the biaxiality ratio of the loading. The scattering of the biaxial strength data was analyzed using the Weibull distribution. The axial contraction of carbon fiber-reinforced plastic (CFRP) tubes under biaxial loading was investigated theoretically and experimentally. Artificial neural networks were introduced to predict the failure strength using the algorithm of the error back-propagation. The prediction was also made by the Tsai-Wu theory using the experimental data and by the combined optimized tensor-polynomial theory. A comparison shows that the artificial neural network has the smallest root-mean square (RMS) error of the three prediction methods. The prediction of the axial contraction of the tubes correlates well with the results of a linear variable differential transformer (LVDT) of the testing machine. From the phenomenological analysis of the failure and the fractographic observations of the fracture surface, three types of failure modes and microscopic failure were investigated, depending on the biaxiality ratio, and the corresponding failure mechanisms are suggested.

  12. Weld failure detection

    DOEpatents

    Pennell, William E.; Sutton, Jr., Harry G.

    1981-01-01

    Method and apparatus for detecting failure in a welded connection, particrly applicable to not readily accessible welds such as those joining components within the reactor vessel of a nuclear reactor system. A preselected tag gas is sealed within a chamber which extends through selected portions of the base metal and weld deposit. In the event of a failure, such as development of a crack extending from the chamber to an outer surface, the tag gas is released. The environment about the welded area is directed to an analyzer which, in the event of presence of the tag gas, evidences the failure. A trigger gas can be included with the tag gas to actuate the analyzer.

  13. BIOASSAY VESSEL FAILURE ANALYSIS

    SciTech Connect

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  14. Basic failure mechanisms in advanced composites

    NASA Technical Reports Server (NTRS)

    Mullin, J. V.; Mazzio, V. F.; Mehan, R. L.

    1971-01-01

    Fundamental failure mechanisms in carbon-epoxy composites were studied for more reliable prediction of the performance of these materials. Single and multiple fiber specimens were tested under tensile loads, and the sequence of failure events was observed. Parameters such as resin crack sensitivity, fiber surface treatment and variations in fibers from batch to batch are being evaluated. The analysis of bulk composite fracture processes using acoustic emission techniques is being studied in order to correlate microscopic observations with bulk composite behavior. Control of the fracture process through matrix and interface modification is being attempted, and study of failure processes in composite/metal specimens is being conducted. Most of the studies involved DEN 438 epoxy novolac as the matrix, but some experiments are now underway using the higher temperature resin ERLA 4617.

  15. Regional Lymph Node Uptake of [18F]Fluorodeoxyglucose After Definitive Chemoradiation Therapy Predicts Local-Regional Failure of Locally Advanced Non-Small Cell Lung Cancer: Results of ACRIN 6668/RTOG 0235

    PubMed Central

    Markovina, Stephanie; Duan, Fenghai; Snyder, Bradley S.; Siegel, Barry A.; Machtay, Mitchell; Bradley, Jeffrey

    2015-01-01

    Purpose/Objective(s) ACRIN 6668/RTOG 0235 demonstrated that standardized uptake value (SUV) on post-treatment [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) correlates with survival in locally advanced non-small cell lung cancer (NSCLC). This secondary analysis determines if SUV of regional lymph nodes (RLNs) on post-treatment FDG-PET correlates with patient outcomes. Methods and Materials Included for analysis were patients treated with concurrent chemoradiation therapy using radiation doses ≥60 Gy, with identifiable FDG-avid RLNs (distinct from primary tumor) on pre-treatment FDG-PET, and post-treatment FDG-PET data. ACRIN Core Laboratory SUV measurements were used. Event time was calculated from the date of post-treatment FDG-PET. Local-regional failure was defined as failure within the treated RT volume and reported by the treating institution. Statistical analyses included Wilcoxon signed-rank test, Kaplan-Meier curves (log rank test), and Cox proportional hazards regression modeling. Results Of 234 trial-eligible patients, 139 (59%) had uptake in both primary tumor and RLNs on pre-treatment FDG-PET, and had SUV data from post-treatment FDG-PET. Maximum SUV was greater for primary tumor than for RLNs before treatment (p<0.001), but not different post-treatment (p=0.320). Post-treatment SUV of RLNs was not associated with overall survival. However, elevated post-treatment SUV of RLNs, both the absolute value and the percent residual activity compared to the pre-treatment SUV, were associated with inferior local-regional control (p<0.001). Conclusions High residual metabolic activity in RLNs on post-treatment FDG-PET is associated with worse local-regional control. Based on these data, future trials evaluating a radiotherapy boost should consider inclusion of both primary tumor and FDG-avid RLNs in the boost volume to maximize local-regional control. PMID:26461002

  16. Development of a clinical prediction rule to improve peripheral intravenous cannulae first attempt success in the emergency department and reduce post insertion failure rates: the Vascular Access Decisions in the Emergency Room (VADER) study protocol

    PubMed Central

    Carr, Peter J; Rippey, James C R; Cooke, Marie L; Bharat, Chrianna; Murray, Kevin; Higgins, Niall S; Foale, Aileen; Rickard, Claire M

    2016-01-01

    Introduction Peripheral intravenous cannula (PIVC) insertion is one of the most common clinical interventions performed in emergency care worldwide. However, factors associated with successful PIVC placement and maintenance are not well understood. This study seeks to determine the predictors of first time PIVC insertion success in emergency department (ED) and identify the rationale for removal of the ED inserted PIVC in patients admitted to the hospital ward. Reducing failed insertion attempts and improving peripheral intravenous cannulation practice could lead to better staff and patient experiences, as well as improving hospital efficiency. Methods and analysis We propose an observational cohort study of PIVC insertions in a patient population presenting to ED, with follow-up observation of the PIVC in subsequent admissions to the hospital ward. We will collect specific PIVC observational data such as; clinician factors, patient factors, device information and clinical practice variables. Trained researchers will gather ED PIVC insertion data to identify predictors of insertion success. In those admitted from the ED, we will determine the dwell time of the ED-inserted PIVC. Multivariate regression analyses will be used to identify factors associated with insertions success and PIVC failure and standard statistical validation techniques will be used to create and assess the effectiveness of a clinical predication rule. Ethics and dissemination The findings of our study will provide new evidence to improve insertion success rates in the ED setting and identify strategies to reduce premature device failure for patients admitted to hospital wards. Results will unravel a complexity of factors that contribute to unsuccessful PIVC attempts such as patient and clinician factors along with the products, technologies and infusates used. Trial registration number ACTRN12615000588594; Pre-results. PMID:26868942

  17. SCADA alarms processing for wind turbine component failure detection

    NASA Astrophysics Data System (ADS)

    Gonzalez, E.; Reder, M.; Melero, J. J.

    2016-09-01

    Wind turbine failure and downtime can often compromise the profitability of a wind farm due to their high impact on the operation and maintenance (O&M) costs. Early detection of failures can facilitate the changeover from corrective maintenance towards a predictive approach. This paper presents a cost-effective methodology to combine various alarm analysis techniques, using data from the Supervisory Control and Data Acquisition (SCADA) system, in order to detect component failures. The approach categorises the alarms according to a reviewed taxonomy, turning overwhelming data into valuable information to assess component status. Then, different alarms analysis techniques are applied for two purposes: the evaluation of the SCADA alarm system capability to detect failures, and the investigation of the relation between components faults being followed by failure occurrences in others. Various case studies are presented and discussed. The study highlights the relationship between faulty behaviour in different components and between failures and adverse environmental conditions.

  18. Congestive Heart Failure.

    PubMed

    Scott, Michael C; Winters, Michael E

    2015-08-01

    Patients with acute decompensated heart failure are usually critically ill and require immediate treatment. However, most are not volume overloaded. Emergency department (ED) management is based on rapid initiation of noninvasive positive-pressure ventilation and aggressive titration of nitrates. Afterload reduction with an angiotensin-converting enzyme inhibitor can be considered. A diuretic should not be administered before optimal preload and afterload reduction has been achieved. Short-term inotropic therapy can be considered in select patients with cardiogenic shock and acute decompensated heart failure (ADHF) who fail to respond to standard therapy.

  19. Failure detection and identification

    NASA Technical Reports Server (NTRS)

    Massoumnia, Mohammad-Ali; Verghese, George C.; Willsky, Alan S.

    1989-01-01

    Using the geometric concept of an unobservability subspace, a solution is given to the problem of detecting and identifying control system component failures in linear, time-invariant systems. Conditions are developed for the existence of a causal, linear, time-invariant processor that can detect and uniquely identify a component failure, first for the case where components can fail simultaneously, and then for the case where they fail only one at a time. Explicit design algorithms are provided when these conditions are satisfied. In addition to time-domain solvability conditions, frequency-domain interpretations of the results are given, and connections are drawn with results already available in the literature.

  20. Common Cause Failure Modes

    NASA Technical Reports Server (NTRS)

    Wetherholt, Jon; Heimann, Timothy J.; Anderson, Brenda

    2011-01-01

    High technology industries with high failure costs commonly use redundancy as a means to reduce risk. Redundant systems, whether similar or dissimilar, are susceptible to Common Cause Failures (CCF). CCF is not always considered in the design effort and, therefore, can be a major threat to success. There are several aspects to CCF which must be understood to perform an analysis which will find hidden issues that may negate redundancy. This paper will provide definition, types, a list of possible causes and some examples of CCF. Requirements and designs from NASA projects will be used in the paper as examples.

  1. Hypothyroid acute renal failure.

    PubMed

    Birewar, Sonali; Oppenheimer, Mark; Zawada, Edward T

    2004-03-01

    Muscular disorders and even hypothyroid myopathy with elevated muscle enzymes are commonly seen in hypothyroidism. In this paper, we report a case of acute renal failure in a 35-year old male patient with myalgia. His serum creatinine reached a level of 2.4 mg/dl. Later, his myalgia was found to be due to hypothyroidism with TSH of over 500 uiv/ml. With thyroid replacement therapy, myalgia and his serum creatinine stabilized and subsequently improved. Hypothyroidism, although rare, has been reported as a definite and authentic cause of rhabdomyolysis. As a result, hypothyroidism must be considered in patients presenting with acute renal failure and elevated muscle enzymes.

  2. Analysis of cascading failure in gene networks.

    PubMed

    Sun, Longxiao; Wang, Shudong; Li, Kaikai; Meng, Dazhi

    2012-01-01

    It is an important subject to research the functional mechanism of cancer-related genes make in formation and development of cancers. The modern methodology of data analysis plays a very important role for deducing the relationship between cancers and cancer-related genes and analyzing functional mechanism of genome. In this research, we construct mutual information networks using gene expression profiles of glioblast and renal in normal condition and cancer conditions. We investigate the relationship between structure and robustness in gene networks of the two tissues using a cascading failure model based on betweenness centrality. Define some important parameters such as the percentage of failure nodes of the network, the average size-ratio of cascading failure, and the cumulative probability of size-ratio of cascading failure to measure the robustness of the networks. By comparing control group and experiment groups, we find that the networks of experiment groups are more robust than that of control group. The gene that can cause large scale failure is called structural key gene. Some of them have been confirmed to be closely related to the formation and development of glioma and renal cancer respectively. Most of them are predicted to play important roles during the formation of glioma and renal cancer, maybe the oncogenes, suppressor genes, and other cancer candidate genes in the glioma and renal cancer cells. However, these studies provide little information about the detailed roles of identified cancer genes.

  3. Electrical overstress failure in silicon solar cells

    SciTech Connect

    Pease, R.L.; Barnum, J.R.; van Lint, V.A.J.; Vulliet, W.V.; Wrobel, T.F.

    1982-11-01

    A solar-cell electrical-overstress-failure model and the results of experimental measurements of threshold pulsed failure currents on four types of silicon solar cells are presented. The transient EMP field surrounding a lightning stroke has been identified as a potential threat to a p