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Providence, RI, United States

Suresh N.,RIC Inc
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference

The objective of this pilot study was to examine alterations in motor unit (MU) control properties, (i.e. MU recruitment and firing rate) after stroke utilizing a recently developed high-yield surface electromyogram (EMG) decomposition technique. Two stroke subjects participated in this study. A sensor array was used to record surface EMG signals from the first dorsal interosseous (FDI) muscle during voluntary isometric contraction at varying force levels. The recording was performed in both paretic and contralateral muscles using a matched force protocol. Single motor unit activity was extracted using the surface EMG decomposition software from Delsys Inc. The results from the two stroke subjects indicate a reduction in the mean motor unit firing rate and a compression of motor unit recruitment range in paretic muscle as compared with the contralateral muscles. These findings provide further evidence of spinal motoneuron involvement after a hemispheric brain lesion, and help us to understand the complex origins of stroke induced muscle weakness. Source

Salehghaffari S.,Northwestern University | Salehghaffari S.,RIC Inc
International Journal of Reliability and Safety

The aggregation rule is critical when a high degree of conflict between different sources of data or expert opinions exists. In this paper, we will present a new evidence aggregation rule that makes use of Ground Probability Assignment (GPA) developed by Yager along with a proposed Credibility Factor of Evidence (CFE). Observed experimental evidences on simulation responses or commonly used values of uncertain parameters are used for the CFE estimation. The new aggregation rule is adopted for uncertainty modelling of a large deformation process represented by the Taylor impact test for which Johnson-Cook and Zerilli-Armstrong plasticity models provide different answers. The uncertainty modelling procedure also accommodates both epistemic and aleatory uncertainty embedded in material constants of the adopted plasticity models. Results of uncertainty representation, propagation and quantification for Taylor impact tests of AISI 4340 Steel have shown that the suggested aggregation rule is very efficient in recognising key information or knowledge from different sources, which helps to reduce epistemic uncertainty. Copyright © 2013 Inderscience Enterprises Ltd. Source

The rate constant of the reaction Cl + CF 3CF=CH 2 (k 1) has been measured relative to several reference species using the relative rate technique with either gas chromatographic analysis with flame-ionization detection (GC/FID) or Fourier transform infrared (FTIR) analysis. Cl atoms were generated by UV irradiation of Cl 2/CF 3CF=CH 2/reference/N 2/O 2 mixtures. At 300-400 K in the presence of >20 Torr O 2, k 1 = 1.2 × 10 -11 e (+1100/RT) cm 3 molecule -1 s -1. In N 2 diluent, k 1 has a sharp negative temperature coefficient resulting from the relatively small exothermicity of the following reactions: (1a) Cl + CF 3CF=CH 2 ↔ CF 3CFClCH 2(•); (1b) Cl + CF 3CF=CH 2 ↔ CF 3CF(•)CH 2Cl (reaction 1), which were determined in these experiments to be ∼16.5 (±2.0) kcal mol -1. This low exothermicity causes reaction 1 to become significantly reversible even at ambient temperature. The rate constant ratio for the reaction of the chloroalkyl radicals formed in reaction 1 with Cl 2 (k 2) or O 2 (k 3) was measured to be k 2/k 3 = 0.4 e -(3000/RT) for 300-400 K. At 300 K, k 2/k 3 = 0.0026. The reversibility of reaction 1 combined with the small value of k 2/k 3 leads to a sensitive dependence of k 1 on the O 2 concentration. Products measured by GC/FID as a function of temperature are CF 3CFClCH 2Cl, CF 3COF, and CH 2Cl 2. The mechanism leading to these products is discussed. The rate constant for the reaction Cl + CF 3CFClCH 2Cl (k 11) was measured as a function of temperature (300-462 K) at 760 Torr to be k 11 = 8.2 × 10 -12 e -(4065/RT) cm 3 molecule -1 s -1. Rate constants relative to CH 4 for the reactions of Cl with the reference compounds CH 3Cl, CH 2Cl 2, and CHCl 3 were measured at 470 K to resolve a literature discrepancy. (R = 1.986 cal K -1 mol -1). © 2012 American Chemical Society. Source

Kaiser E.W.,University of Michigan | Wallington T.J.,RIC Inc
International Journal of Chemical Kinetics

The rate constant of the reaction Cl + CH 3OH (k 1) has been measured in 500-950 Torr of N 2 over the temperature range 291-475 K. The rate constant determination was carried out using the relative rate technique with C 2H 6 as the reference compound. Experiments were performed by irradiating mixtures of CH 3OH, C 2H 6, Cl 2, and N 2 with UV light from a fluorescent lamp whose intensity peaked near 360 nm. The resultant temperature-dependent rate expression is k 1 =8.6 (±1.3) × 10 -11 exp[-167 (±60)/T] cm 3 molecule -1 s -1. Error limits represent data scatter (2σ) in the current experiments and do not include error in the reference rate constant. © 2009 Wiley Periodicals, Inc. Source

RIC Inc | Date: 2012-06-29

A seal for a respiratory mask that includes a first end portion adapted to be coupled to a mask shell, a second end portion for sealing engagement with a face of a patient, and a sidewall extending between the first end portion and the second end portion. At least a portion of the second end portion includes a textured area having a predetermined pattern. The area of increased surface roughness provides the patient contacting portion of the seal with a silky feeling to maximize patient comfort and the effectiveness of the seal without impairing the sealing ability.

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