Risk for Clostridium difficile infection after allogeneic hematopoietic cell transplant remains elevated in the postengraftment period

BACKGROUND: Clostridium difficile infection (CDI) is a frequent cause of diarrhea among allogeneic hematopoietic cell transplant (HCT) recipients. It is unknown whether risk factors for CDI vary by time posttransplant. METHODS: We performed a 3-year prospective cohort study of CDI in allogeneic HCT recipients. Participants were enrolled during their transplant hospitalizations. Clinical assessments were performed weekly during hospitalizations and for 12 weeks posttransplant, and monthly for 30 months thereafter. Data were collected through patient interviews and chart review, and included CDI diagnosis, demographics, transplant characteristics, medications, infections, and outcomes. CDI cases were included if they occurred within 1 year of HCT and were stratified by time from transplant. Multivariable logistic regression was used to determine risk factors for CDI. RESULTS: One hundred eighty-seven allogeneic HCT recipients were enrolled, including 63 (34%) patients who developed CDI. 38 (60%) CDI cases occurred during the preengraftment period (days 0-30 post-HCT) and 25 (40%) postengraftment (day >30). Lack of any preexisting comorbid disease was significantly associated with lower risk of CDI preengraftment (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.1-0.9). Relapsed underlying disease (OR, 6.7; 95% CI, 1.3-33.1), receipt of any high-risk antimicrobials (OR, 11.8; 95% CI, 2.9-47.8), and graft-versus-host disease (OR, 7.8; 95% CI, 2.0-30.2) were significant independent risk factors for CDI postengraftment. CONCLUSIONS: A large portion of CDI cases occurred during the postengraftment period in allogeneic HCT recipients, suggesting that surveillance for CDI should continue beyond the transplant hospitalization and preengraftment period. Patients with continued high underlying severity of illness were at increased risk of CDI postengraftment

Linear active disturbance rejection control of waste heat recovery systems with organic Rankine cycles

In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power demand variations of grid and process disturbances. The effectiveness of this controller is verified via a simulation study, and the results demonstrate that the proposed strategy can provide satisfactory tracking performance and disturbance rejection

Validation of a multivariable relay-based PID autotuner with specified robustness

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Perioperative Pleural Drainage in Liver Transplantation: A Retrospective Analysis from a High-Volume Liver Transplant Center

BACKGROUND Pleural effusions represent a common complication after liver transplantation (LT) and chest drain (CD) placement is frequently necessary. MATERIAL AND METHODS In this retrospective cohort study, adult LT recipients between 2009 and 2016 were analyzed for pleural effusion formation and its treatment within the first 10 postoperative days. The aim of the study was to compare different settings of CD placement with regard to intervention-related complications. RESULTS Overall, 597 patients met the inclusion criteria, of which 361 patients (60.5%) received at least 1 CD within the study period. Patients with a MELD >25 were more frequently affected (75.7% versus 56.0%, P<0.001). Typically, CDs were placed in the intensive care unit (ICU) (66.8%) or in the operating room (14.1% during LT, 11.5% in the context of reoperations). In total, 97.0% of the patients received a right-sided CD, presumably caused by local irritations. Approximately one-third (35.4%) of ICU-patients required pre-interventional optimization of coagulation. Of the 361 patients receiving a CD, 15 patients (4.2%) suffered a post-interventional hemorrhage and 6 patients (1.4%) had a pneumothorax requiring further treatment. Less complications were observed when the CD was performed in the operating room compared to the ICU: 1 out 127 patients (0.8%) versus 20 out of 332 patients (6.0%); P=0.016. CONCLUSIONS CD placement occurring in the operating room was associated with fewer complications in contrast to placement occurring in the ICU. Planned CD placement in the course of surgery might be favorable in high-risk patients

Application of optimal control theory to the design of the NASA/JPL 70-meter antenna servos

The application of Linear Quadratic Gaussian (LQG) techniques to the design of the 70-m axis servos is described. Linear quadratic optimal control and Kalman filter theory are reviewed, and model development and verification are discussed. Families of optimal controller and Kalman filter gain vectors were generated by varying weight parameters. Performance specifications were used to select final gain vectors

MIMO PID Controller Tuning Method for Quadrotor Based on LQR/LQG Theory

In this work, a new pre-tuning multivariable PID (Proportional Integral Derivative) controllers method for quadrotors is put forward. A procedure based on LQR/LQG (Linear Quadratic Regulator/Gaussian) theory is proposed for attitude and altitude control, which suposes a considerable simplification of the design problem due to only one pretuning parameter being used. With the aim to analyze the performance and robustness of the proposed method, a non-linear mathematical model of the DJI-F450 quadrotor is employed, where rotors dynamics, together with sensors drift/bias properties and noise characteristics of low-cost commercial sensors typically used in this type of applications are considered. In order to estimate the state vector and compensate bias/drift effects in the measures, a combination of filtering and data fusion algorithms (Kalman filter and Madgwick algorithm for attitude estimation) are proposed and implemented. Performance and robustness analysis of the control system is carried out by employing numerical simulations, which take into account the presence of uncertainty in the plant model and external disturbances. The obtained results show the proposed controller design method for multivariable PID controller is robust with respect to: (a) parametric uncertainty in the plant model, (b) disturbances acting at the plant input, (c) sensors measurement and estimation errors

Environmental test chamber for the support of learning and teaching in intelligent control

The paper describes the utility of a low cost, 1 m2 by 2 m forced ventilation, micro-climate test chamber, for the support of research and teaching in mechatronics. Initially developed for the evaluation of a new ventilation rate controller, the fully instrumented chamber now provides numerous learning opportunities and individual projects for both undergraduate and postgraduate research students

Liver transplantation for alcoholic liver disease: a retrospective analysis of recidivism, survival and risk factors predisposing to alcohol relapse

Background and study aims : Alcoholic liver disease (ALD) is the second most common indication for liver transplantation. The aim of this study was to evaluate the alcohol relapse rate and long-term survival after liver transplantation for ALD and to identify risk factors predisposing to alcohol relapse. Patients and methods : Between 2000 and 2007, 108 patients transplanted for ALD in the Ghent University Hospital were included in this retrospective analysis. Relapse was defined as any drinking after transplantation, problem drinking as more than 2 units/day for women and 3 units/day for men. A wide range of variables was obtained from a questionnaire and medical records. Results : The mean follow-up was 55 months. Relapse was observed in 29%, 16% in problem drinking. The one-and five-year survival was 87% and 74% respectively. No significant difference in survival was found between non-relapsers, occasional drinkers and problem drinkers. The following risk factors were found to be significantly associated with relapse into problem drinking in an univariate analysis : a shorter pre-transplant abstinence period, the presence of a first degree relative with alcohol abuse and a higher number of prior attempts to quit. In multivariable analysis, the presence of a first degree relative with alcohol abuse was found associated with relapse into problem drinking. Conclusions : The presence of a first degree relative with alcohol abuse is a valuable pre-transplant variable evaluating an ALD patient's eligibility for liver transplantation. Other variables are also helpful to outline the broader context of the drinking behavior of the patient

A survey of fuzzy control for stabilized platforms

This paper focusses on the application of fuzzy control techniques (fuzzy type-1 and type-2) and their hybrid forms (Hybrid adaptive fuzzy controller and fuzzy-PID controller) in the area of stabilized platforms. It represents an attempt to cover the basic principles and concepts of fuzzy control in stabilization and position control, with an outline of a number of recent applications used in advanced control of stabilized platform. Overall, in this survey we will make some comparisons with the classical control techniques such us PID control to demonstrate the advantages and disadvantages of the application of fuzzy control techniques