Towards developing a coupled stability theory for haptic systems, we study the interaction of operators with time-delayed force feedback. In this work, we analyzed and validated experimentally the stability boundaries of an uncoupled system - without considering the human. We then designed an experiment in which the participants used a haptic device to interact with virtual elastic force fields in a stiffness discrimination task. We compared the performance and kinematics of users in uncoupled-unstable and uncoupled-stable conditions and characterized the stabilizing contribution of the users. We found that the users were able to perform the task regardless of the uncoupled-stability conditions. In addition, in uncoupled-unstable conditions, users maintained movement characteristics that were important for exploratory mediation, such as depth and duration of the movement, whereas other characteristics were not preserved. The results were reproduced in a simulation of the human controller that combined an inverse model and an optimal feedback controller. Adequate performance under the uncoupled-unstable yet coupled-stable conditions supports the potential benefit of designing for coupled stability of haptic systems. This could lead to the use of less conservative controllers than state-of-the-art solutions in haptic and teleoperation systems, and advance the fidelity of haptic feedback.
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http://dx.doi.org/10.1109/TOH.2022.3221919 | DOI Listing |
J Biol Chem
January 2025
Departments of Neurology, University of Michigan, Ann Arbor, MI 48109; Departments of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109; Neurology Service, VA Ann Arbor Healthcare System, Department of Veterans Affairs, Ann Arbor, MI 48105. Electronic address:
Stereotyped mutations in NOTCH3 drive CADASIL, the leading inherited cause of stroke and vascular dementia. The vast majority of these mutations result in alterations in the number of cysteines in the gene product. However, non-cysteine altering pathogenic mutations have also been identified, making it challenging to discriminate pathogenic from benign NOTCH3 sequence variants.
View Article and Find Full Text PDFDokl Biol Sci
January 2025
Research Center of Neurology, Moscow, Russia.
Characteristic patterns of UV-induced skin autofluorescence were determined for patients with Parkinson's disease (PD) and associated with dysmetabolic alterations, such as nonenzymatic protein glycation, an increase in extracellular matrix stiffness, impaired metabolism of tissue fluorophores, mitochondrial dysfunction, and accumulation of aberrant proteins. Key differences in skin autofluorescence spectra were for the first time observed in PD, making it possible to discriminate between PD patients and healthy persons or individuals without signs of chronic neurodegeneration. Namely, skin fluorescence related to the reflected signal upon excitation with UV light at 375 nm was lower in PD patients.
View Article and Find Full Text PDFIndian J Clin Biochem
January 2025
Department of Biochemistry, Velammal Medical College Hospital and Research Institute, Madurai, Tamil Nadu 632002 India.
Unlabelled: Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of chronic liver disease worldwide. There are conflicting reports on the association of serum ferritin levels and its utility in discriminating various stages of liver fibrosis in patients with NAFLD. This study is done to address the conflicts by analysing the National Health and Nutritional Examination Survey 2017-2020 (NHANES 2017-2020) data.
View Article and Find Full Text PDFJ Clin Hypertens (Greenwich)
January 2025
Department of Cardiovascular Medicine, Shanghai Key Laboratory of Hypertension, Shanghai Institute of Hypertension, State Key Laboratory of Medical Genomics, National Research Centre for Translational Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Prognostic significance of the timing in the cardiac cycle of the first (TP1) and second (TP2) systolic peak of the central aortic pulse wave is ill-defined. Incidence rates and standardized multivariable-adjusted hazard ratios (HRs) of adverse health outcomes associated with TP1 and TP2, estimated by the SphygmoCor software, were assessed in the International Database of Central Arterial Properties for Risk Stratification (IDCARS) (n = 5529). Model refinement was assessed by the integrated discrimination (ID) and net reclassification (NR) improvement.
View Article and Find Full Text PDFHepatology
February 2025
Department of Medicine III, Division of Gastroenterology and Hepatology, Medical University of Vienna, Vienna, Austria.
Background And Aims: Around 750,000 patients per year will be cured of HCV infection until 2030. Those with compensated advanced chronic liver disease remain at risk for hepatic decompensation and de novo HCC. Algorithms have been developed to stratify risk early after cure; however, data on long-term outcomes and the prognostic utility of these risk stratification algorithms at later time points are lacking.
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