Browsing by Author "Pai, S."

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IMU-based segmental root mean square analysis of gait in individuals with cerebellar ataxia: a pilot cross-sectional study
(Nature Research, 2025) Mendonca, J.; Joshua, A.M.; Shetty, S.; Chemmangat, K.; Krishnan, S.; Kumar, K.V.; Misri, Z.; Pai, R.; Pai, S.
Cerebellar ataxia (CA) affects limb movement, balance, and gait. Subjective rating scales like Scale for the Assessment and Rating of Ataxia (SARA) may underestimate gait severity. Inertial measurement units (IMUs) offer an objective gait analysis. Impaired trunk control might compromise gait performance and stability in individuals with ataxia. This study quantified trunk kinematics and gait parameters using Root Mean Square (RMS) values, comparing CA to healthy individuals. Ten CA cases and twenty healthy controls were recruited. Six IMU sensors positioned at anatomical landmarks recorded data via two ESP32 microcontrollers using Wi-Fi. Participants walked a 10-meter path at a self-selected pace. RMS mean linear and angular velocity and angular deviation were calculated. Individuals with CA showed decreased mediolateral linear acceleration at the left shoulder (p = 0.001) and an increased vertical linear acceleration at the right ankle (p = 0.015), left shoulder (p = 0.028), and back (p = 0.019). Total angular velocity was lower at the right shoulder (p = 0.017), left shoulder (p = 0.005), back (p = 0.002), and both ankles (right: p = 0.001; left: p = 0.001). The correlation between IMU-derived features and SARA-gait score in the CA group was not statistically significant (all p > 0.05), except for the right shoulder’s mediolateral angular velocity (p = 0.046). Both ankle segments’ angular deviations (right: p = 0.001; left: p = 0.006) were reduced. The CA group revealed reduced RMS linear and angular velocities. IMU-based trunk and gait analysis provides a more objective method that would help in planning targeted rehabilitation treatments. Trial registration: The study was approved by the Institutional Ethics Committee (IEC), Kasturba Medical College, Mangalore, Manipal Academy of Higher Education (IEC KMC MLR 12/2023/483) on 21st December 2023 and the Clinical Trial Registration (CTRI/2024/07/070614) on July 15th, 2024. © The Author(s) 2025.
Microstructural, electrochemical and immersion based corrosion analysis in milling induced magnesium alloy AZ91
(Russian Association of Corrosion Engineers, 2024) Marakini, V.; Pai, S.; Achar, B.; Sahoo, B.; Bhat K, U.; Devadiga, R.; Rao, S.; Swamy, M.; Mesta, R.
Present work discusses the effect of face milling operations on the corrosion characteristics of AZ91 alloy. A full factorial L27 design of experiment is prepared and face milling is performed to identify the optimal conditions with lowest roughness. The optimal surface of the alloy obtained from face milling has been compared with the slightly polished surface of as-cast alloy using weight loss and electrochemical polarization testing methods using 3.5% NaCl solution. In weight loss method, the alloy surfaces are solution treated for various time intervals ranging from 0.5 to 72 hours, to study the effect of surface finish obtained from face milling in comparison to polishing (as-cast). Whereas, in polarization method, the tests are conducted for only 0.5 hour on both specimens and compared. The corrosion rates are found to be in direct relation to the surface roughness, as the low roughness surface from face milling showed comparatively low corrosion rate. The polarization curves justified the better corrosion resistance of milled surface when compared to polished surface. Further, FESEM micrograph comparison between the before and after polarization test surfaces showed the severity of corrosion attack in both tested surfaces. Furthermore, the elemental analysis using EDAX test on the before and after polarization test surfaces showed the presence of less oxygen in the milled surface compared to polished surface, which established the better corrosion resistance of milled surfaces which has low surface roughness. © 2024, Russian Association of Corrosion Engineers. All rights reserved.
Scaling up green synthesis of silver nanoparticles and their immobilization for water disinfection in a “Point of Use” fixed bed unit
(Elsevier Ltd, 2025) Pai, S.; Shetty K, V.
In the current study, the scale-up effect on the characteristics and water disinfection activity of silver nanoparticles (AgNPs) synthesized by a green synthesis method using the teak leaves extract in an agitated tank system, while scaling up from a base scale of 0.5 L to larger scales of 1 L and 5 L, is investigated. Four different scale-up criteria (constant power output (P/V), constant impeller pump rate (Q/V), constant maximum impeller speed, and constant impeller Reynolds number) were applied for scaling up, while maintaining the geometric similarity. The criterion of constant P/V resulted in disinfection potential and average particle sizes closer to those in the base scale and thus considered as the best scale-up criterion for the teak leaf extract-mediated AgNPs synthesis. The performance of the “Point of Use” fixed-bed water disinfection unit, consisting of a packed bed of Granular Activated Carbon (GAC) immobilized with AgNPs synthesized on a large scale (which was scaled up with the constant P/V criterion), was evaluated. The disinfection unit could successfully produce drinking water without losing the disinfection activity even after multiple uses. © 2025 Elsevier Ltd.