Occipital White Matter Volumes Predict Visual Motor Outcome in Preterm Infants with Retinopathy of Prematurity (ROP)

Although very low birth weight preterm (VLBW) infants with grade 3,4 retinopathy of prematurity (ROP) are at high risk for unfavorable visual outcomes, the middle school vision motor integration (VMI) skills and cognitive outcome scores of these children remain largely unknown. Data for 323 very VLBW survivors of the Multicenter Randomized Indomethacin IVH Prevention Trial (BW 600 1250 g) were analyzed to test the hypothesis that grades 3, 4 ROP would be an important predictor of cognitive and VMI skills. 3 subgroups were evaluated: ROP negative (N = 163), ROP grades 1,2 (N = 137) and ROP grades 3,4 (N = 23) were evaluated prospectively at 12 years of age with a neurocognitive battery. High-resolution volumetric MRI scans were quantified for 40 of the study subjects, and occipital brain volumes were correlated with Beery VMI scores. Children with ROP 3-4 had ↑ vision impairment and lower test scores. Whole brain volumes were significantly less for children with any grade of ROP (p = 0.02), occipital white matter volumes tended to be less for the same study subjects (p = 0.08) and both total occipital brain volumes and occipital white matter volumes were significantly correlated with Beery VMI scores (r=0.610, p = 0.009 and r = 0.652, p =0.005, respectively). Prematurely-born children with a history of grade 3-4 ROP continue to have ↑ vision impairment, special needs and lower performance on cognitive, language and visual motor integration scores at age 12 years. Both whole occipital brain volumes and occipital white matter volumes were predictive of VMI scores for children with ROP. (supp by NS 27116

DEVELOPMENT OF A HIGH-FIDELITY MODEL AND KALMAN FILTER BASED STATE ESTIMATOR FOR SIMULATION AND CONTROL OF NOX REDUCTION PERFORMANCE OF A SCR CATALYST ON A DPF

Reduction of emissions and improving the fuel consumption are two prime research areas in Diesel engine development. The present after-treatment systems being used for emissions control include diesel oxidation catalyst (DOC) for NO, HC and CO oxidation along with catalyzed particulate filters for PM (particulate matter) and selective catalytic reduction (SCR) for controlling NOx emissions. Recently an after-treatment system called SCR catalyst on a DPF capable of simultaneously reducing both NOx and PM emissions has been developed in order to reduce the overall size of the after-treatment system. The goal of this proposed research is to create a state estimator that is capable of estimating the internal states of temperature distribution, PM distribution, NH3 storage faction as well as pressure drop across the filter and outlet concentration of NO, NO2 and NH3 for different operating conditions. This would help in achieving an optimal urea dosing strategy during NOx reduction as well as an optimum fuel dosing strategy during active regeneration for the SCR catalyst on a DPF. The motivation for this research comes from the desire to quantify the interaction of SCR reactions and PM oxidation in the SCR catalyst on a DPF and to use the mathematical model created in the process to develop a state estimator that can provide optimal control and onboard diagnostics of combined SCR catalyst on a DPF devices. In the initial phase of the research a high-fidelity SCR-F model is being developed in MATLAB/Simulink which is capable of predicting the filtration efficiency, temperature distribution, PM distribution, pressure drop across the filter and outlet concentrations of NO, NO2 and NH3. This model will be calibrated using experimental data collected on a Cummins 2013 ISB SCRF®. After the validation of the SCR-F model, the high-fidelity SCR-F model developed will be used with an existing 1D SCR model to perform NOx reduction studies on a system consisting of SCRF® + SCR using experimental data. This step will be followed by development of a reduced order SCR-F model using a coarser mesh (e.g. 5x5 vs 10x10) and simplified governing equations which will also be used as the mathematical model for the state estimator. SCR-F state estimator will be developed to accurately predict the internal states of NH3 coverage fraction, temperature distribution, PM distribution and pressure drop across the SCR catalyst on the DPF. The estimator will be validated using experimental data

Development of a 2D SCR Catalyst on a Diesel Particulate Filter Model for Design and Control Applications to a Ultra Low NOx Aftertreatment System

This research focuses on modeling and control of PM and NOx in diesel engine exhaust using an SCR catalyst on a Diesel Particulate Filter (SCR-F). A 2D SCR-F model was developed that is capable of predicting internal states: 2D temperature, PM and NH3storage distributions and filtration efficiency, pressure drop, PM mass retained in the PM cake and substrate wall and outlet NO, NO2and NH3concentrations. The SCR-F model was used to simulate a DOC + SCR-F + DOC + SCR ultra-low NOx system that can achieve \u3e 99.5% NOx conversion efficiency. The model was calibrated with experimental data from a Johnson Matthey SCRF® with a Cummins 2013 ISB engine. The impact of SCR reactions on passive PM oxidation rate and PM loading on SCR reactions was determined. A comparison of the experimental and model data for different ammonia to NOx ratios, PM loading, and passive oxidation conditions is presented. A 2D SCR-F state estimator was developed by combining a simplified version of the 2D SCR-F model with pressure drop, outlet thermocouple and NOx sensormeasurements using an Extended Kalman Filter. The temperature, PM mass retained and NH3coverage fraction states were predicted which can be used to develop fuel dosing and urea dosing strategies for the SCR-F. A 2D SCR-F + 1D SCR system model was used to simulate the experimental data collected on a SCR-F + SCR system from a Cummins 2013 ISB engine. The NO2/NOxratioat the SCR-F and SCR inlet was found to be limiting factor for NOx conversion efficiency of this system. An ultra-low NOxsystem was developed with a DOC downstream of the SCR-F that maintains an optimum NO2/NOxratio of 0.5 at the downstream SCR inlet by using 2 urea injectors. This system was simulated with a combination of 1D DOC, 2D SCR-F, and 1D SCR models and it was found to be capable of \u3e 99.5% NOxconversion efficiency, a 90% increase in PM oxidation rate compared to an SCR-F + SCR system with 1 injector for typical engine operating conditions

Effect of counter ion concentration added with mixture of water and ethylene glycol on krafft temperature of sodium dodecyl sulfate

Surfactants are amphiphilic organic compounds having both hydrophobic and hydrophilic groups. Surfactants in solution form aggregates known as micelles. The minimum temperature at which surfactants forms micelles is known as Krafft temperature. The Krafft temperature of sodium dodecyl sulfate (SDS) was measured at various counter ion concentrations in two solvent systems, water and 10% ethylene glycol. The Krafft temperature of sodium dodecyl sulfate increased in both water and 10% ethylene glycol with increasing counter ion concentration. The Krafft temperature of sodium dodecyl sulfate in 10% ethylene glycol was higher than the Krafft temperature of sodium dodecyl sulfate in water, at the same counter ion concentration. Since the Krafft temperature of sodium dodecyl sulfate is higher in 10% ethylene glycol than in water at the same counter ion concentration, it has been concluded that the polarity of the solvent plays an important role in increasing the Krafft temperature of sodium dodecyl sulfate

A New Calibration Method for Current Probes

EMC engineers often use current probes to detect common mode currents. It is necessary to characterize the probes up to Giga Hertz frequencies. Existing calibration methods for current clamps suffer from the problem of not directly measuring the current within the current clamp. Instead they either reconstruct the current from measurements at other locations or they use assumptions regarding the geometry which allows them to use a current that is measured at a different location without applying a mathematical correction. The proposed method overcomes these disadvantages by directly measuring the current at the center of the current clamp. This paper also discusses some oftbe non ideal effects ofcurrent clamps

Numerical Modeling of ESD-Simulators

ESD generators are widely used for testing the robustness of electronic equipment against human electrostatic discharge via small metal pieces (e.g. key). Presently the IEC 61000-4-2 ESD standard is hotly discussed to improve test result reproducibility. This paper numerically analyzes an ESD simulator and relates its construction parameters to discharge current and field parameters. It uses FDTD method and models the relay (contact mode discharge) as a material with time dependent conductivity. The process is broken down into a charging phase and a stabilization phase until the electrostatic conditions are reached. Then the conductivity of the relay is changed and the discharge process is simulated. A self-developed code is used to simulate the model. The simulation discharge current, measured ESD simulator\u27s current and IEC reference discharge current are compared Some design choices of the generator are simulated

A New Test Setup and Method for the Calibration of Current Clamps

Current probes are widely used to measure the common mode currents in electromagnetic compatibility (EMC) applications. Often, it is necessary to characterize the ratio of measured voltage to the common mode currents up to gigahertz (GHz) frequencies. Existing calibration methods for current probes suffer from the problem of not directly measuring the current within the current clamp. Instead they either reconstruct the current from measurements at other locations or they use assumptions regarding the geometry which allows them to use a current that is measured at a different location without applying a mathematical correction. For example, by maintaining a 50-Ω transmission-line impedance the current can be determined with low uncertainty. The proposed method overcomes these disadvantages by directly measuring the current at the center of the current clamp. This way the mechanical dimensions of the test setup are not critical any more, i.e., one setup can be easily used to measure a large variety of clamps. The method is primarily applicable for current monitoring probes in the frequency domain

The PCB Level ESD Immunity Study by Using 3 Dimension ESD Scan System

The use of high-speed logic makes modern electronic systems highly susceptible to electrostatic discharge (ESD). Because of their wider bandwidth, faster digital devices are more susceptible to high frequency ESD transient fields. In the analysis of ESD problems, an exact knowledge of the affected PINs and nets is essential for an optimal solution. A three dimensional ESD scanning system, which has been developed to record the ESD susceptibility map for a printed circuit board, is presented, and the mechanisms that the ESD event couples into the digital devices is studied

Sarcomatoid carcinoma of the colon: a rare diagnosis

Report of a rare colon tumor treated successfully using conventional chemotherapy regimen.

Scalability of Multimedia Streaming Service: A Cross Layer Perspective

In this project, we realized a prototype of this architecture to validate the feasibility of the proposed method. According to the experiment, this method could provide efficient self-adaptive multimedia streaming services for varying bandwidth environment. Video streaming is gaining popularity among mobile users. The latest mobile devices, such as smart phones and tablets, are equipped with multiple wireless network interfaces. How to efficiently and cost-effectively utilize multiple links to improve video streaming quality needs investigation. In order to maintain high video streaming quality while reducing the wireless service cost, in this paper, the optimal video streaming process with multiple links is formulated as a Markov Decision Process (MOP). The reward function is designed to consider the quality of service (QoS) requirements for video traffic, such as the startup latency, playback fluency, average playback quality, playback smoothness and wireless service cost. To solve the MOP in real-time, we propose an adaptive, best-action search algorithm to obtain a sub-optimal solution. To evaluate the performance of the proposed adaptation algorithm, we implemented a test bed using the Android mobile phone and the Scalable Video Coding (SVC) codec. Experiment results demonstrate the feasibility and effectiveness of the proposed adaptation algorithm for mobile video streaming applications, which outperforms the existing state-of-the-art adaptation algorithms