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"Reactive stepping"

Tejal Kajrolkar, Tanvi Bhatt
Community-dwelling stroke survivors show a high incidence of falls with unexpected external perturbations during dynamic activities like walking. Previous evidence has demonstrated the importance of compensatory stepping to restore dynamic stability in response to perturbations in hemiparetic stroke survivors. However, these studies were limited to either stance perturbations or perturbation induced under the unaffected limb. This study aimed to compare the differences, if any, between the non-paretic and paretic sides in dynamic stability and protective stepping strategies when exposed to unexpected external perturbation during walking...
June 6, 2016: Journal of Biomechanics
Elizabeth L Inness, Avril Mansfield, Mark Bayley, William E McIlroy
BACKGROUND AND PURPOSE: Impaired features of reactive stepping, specifically delays in the early time to foot off (TFO) phase, are associated with increased fall rates after stroke. This study aimed to determine differences in, and determinants of, paretic and nonparetic limb TFO, and to determine whether both paretic and nonparetic TFO were associated with perturbation-evoked falls. METHODS: Retrospective chart review of 105 individuals with stroke was performed within an inpatient rehabilitation setting; each had received a standardized assessment of reactive balance control (in response to a perturbation) at time of discharge...
July 2016: Journal of Neurologic Physical Therapy: JNPT
Francesco Dose, Giuliano Taccola
OBJECTIVES: Explore the primary characteristics of afferent noisy stimuli, which optimally activate locomotor patterns at low intensity. MATERIALS AND METHODS: Intracellular and extracellular electrophysiological traces were derived from single motoneurons and from ventral roots, respectively. From these recordings, we obtained noisy stimulating protocols, delivered to a dorsal root (DR) of an isolated neonatal rat spinal cord, while recording fictive locomotion (FL) from ventral roots...
August 2016: Neuromodulation: Journal of the International Neuromodulation Society
Tyler B Weaver, Stephen N Robinovitch, Andrew C Laing, Yijian Yang
OBJECTIVES: To compare the fall characteristics of individuals with and without Parkinson's disease (PD) through the analysis of real-life falls captured on video. DESIGN: Observational cohort study. SETTING: Two long-term care facilities in British Columbia, Canada. PARTICIPANTS: Individuals living in long-term care (N=306; 16 with PD). MEASUREMENTS: Falls captured on video and analyzed (N=906; 71 in participants with PD)...
January 2016: Journal of the American Geriatrics Society
Yoshiro Okubo, Daniel Schoene, Stephen R Lord
OBJECTIVE: To examine the effects of stepping interventions on fall risk factors and fall incidence in older people. DATA SOURCE: Electronic databases (PubMed, EMBASE, CINAHL, Cochrane, CENTRAL) and reference lists of included articles from inception to March 2015. STUDY SELECTION: Randomised (RCT) or clinical controlled trials (CCT) of volitional and reactive stepping interventions that included older (minimum age 60) people providing data on falls or fall risk factors...
January 8, 2016: British Journal of Sports Medicine
Lin Li, Frank Abild-Pedersen, Jeff Greeley, Jens K Nørskov
We present calculated adsorption energies of oxygen on gold and platinum clusters with up to 923 atoms (3 nm diameter) using density functional theory. We find that surface tension of the clusters induces a compression, which weakens the bonding of adsorbates compared with the bonding on extended surfaces. The effect is largest for close-packed surfaces and almost nonexistent on the more reactive steps and edges. The effect is largest at low coverage and decreases, even changing sign, at higher coverages where the strain changes from compressive to tensile...
October 1, 2015: Journal of Physical Chemistry Letters
Ruopeng Sun, John B Shea
The present study investigated the attention allocation during reactive stepping using a continuous finger-tapping task. Ten healthy young subjects were recruited to participate in this study. Subjects were required to perform a rapid voluntary step with either left or right leg after hearing an auditory tone while tapping their right index finger on a handhold numeric keypad. Step initiation conditions included simple and choice reaction forward stepping with three variants of continuous tapping task that were: (1) single task--no concurrent finger-tapping task; (2) dual task easy--one-button tapping task; (3) dual task hard--four-button tapping task...
April 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Manjula Gandhi Selvaraj, Devi Shree Jayabal, Thenmozhi Srinivasan, Palanisamy Balasubramanie
A key differentiator in a competitive market place is customer satisfaction. As per Gartner 2012 report, only 75%-80% of IT projects are successful. Customer satisfaction should be considered as a part of business strategy. The associated project parameters should be proactively managed and the project outcome needs to be predicted by a technical manager. There is lot of focus on the end state and on minimizing defect leakage as much as possible. Focus should be on proactively managing and shifting left in the software life cycle engineering model...
2015: TheScientificWorldJournal
Prakruti Patel, Tanvi Bhatt
This study aimed to examine the effect of explicit cuing on reactive stepping with the paretic limb during slip-like perturbations in stroke survivors and to identify differences in postural stability and fall-risk while stepping with either limb. Eleven chronic hemiparetic stroke survivors received slip-like stance perturbations in no-cue (implicit, no instructions) and cued (explicit, instructions to step with paretic limb) conditions. Frequency of stepping with the paretic limb was recorded. Differences between non-paretic and paretic steps for falls, number of compensatory steps, relative center-of-mass position (X COM/BOS), and velocity (Ẋ(COM/BOS)), and vertical limb support (hip descent-Z hip) were analyzed...
November 2015: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Cuiyun Hu, Caifang Yu, Yanhua Liu, Xianhui Hou, Xiaoyun Liu, Yunfei Hu, Changwen Jin
Evolution of enzymes plays a crucial role in obtaining new biological functions for all life forms. Arsenate reductases (ArsC) are several families of arsenic detoxification enzymes that reduce arsenate to arsenite, which can subsequently be extruded from cells by specific transporters. Among these, the Synechocystis ArsC (SynArsC) is structurally homologous to the well characterized thioredoxin (Trx)-coupled ArsC family but requires the glutaredoxin (Grx) system for its reactivation, therefore classified as a unique Trx/Grx-hybrid family...
September 4, 2015: Journal of Biological Chemistry
Pooja Salot, Prakruti Patel, Tanvi Bhatt
BACKGROUND: An effective compensatory stepping response is the first line of defense for preventing a fall during sudden large external perturbations. The biomechanical factors that contribute to heightened fall risk in survivors of stroke, however, are not clearly understood. It is known that impending sensorimotor and balance deficits poststroke predispose these individuals to a risk of fall during sudden external perturbations. OBJECTIVE: The purpose of this study was to examine the mechanism of fall risk in survivors of chronic stroke when exposed to sudden, slip-like forward perturbations in stance...
March 2016: Physical Therapy
Mustafa Halawi, Naeem Khan, Neil Blake
Human herpesvirus 6B (HHV6B) infects over 90% of the population, and normally establishes a latent infection, where episodes of reactivation are asymptomatic. However, in immunocompromised patients HHV6B reactivation is associated with high morbidity and mortality. Cellular immunotherapy has been utilised against other herpesvirus in immunocompromised settings. However, limited information on the immune response against HHV6B has hampered the development of immunotherapy for HHV6B-driven disease. In this study, we have analysed the cellular immune response against four HHV6B antigens in a panel of 30 healthy donors...
June 2015: Immunity, Inflammation and Disease
Paul M Zimmerman
Reaction path finding and transition state (TS) searching are important tasks in computational chemistry. Methods that seek to optimize an evenly distributed set of structures to represent a chemical reaction path are known as double-ended string methods. Such methods can be highly reliable because the endpoints of the string are fixed, which effectively lowers the dimensionality of the reaction path search. String methods, however, require that the reactant and product structures are known beforehand, which limits their ability for systematic exploration of reactive steps...
April 5, 2015: Journal of Computational Chemistry
Darren R Hocking, Claudine M Kraan, David E Godler, Quang M Bui, Xin Li, John L Bradshaw, Nellie Georgiou-Karistianis, Sylvia A Metcalfe, Alison D Archibald, Erin Turbitt, Joanne Fielding, Julian Trollor, Jonathan Cohen, Kim M Cornish
Recent studies in young adult females with the fragile X mental retardation 1 (FMR1) gene premutation (PM) have shown subtle but significant impairments in executive control and postural stability. Less is known about the influence of age and FMR1 gene expression on executive control and postural stability in females with the PM. Here, we examined the attentional demands of reactive stepping using a well-validated measure of choice stepping reaction time under dual-task interference. We explored the interrelationships between step initiation times during a concurrent verbal fluency task and specific impairments in executive control previously reported in females with the PM...
March 2015: Neurobiology of Aging
Rui Pedro Galvao, Anita Kasina, Robert S McNeill, Jordan E Harbin, Oded Foreman, Roel G W Verhaak, Akiko Nishiyama, C Ryan Miller, Hui Zong
How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared with their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma...
October 7, 2014: Proceedings of the National Academy of Sciences of the United States of America
Digna de Kam, Jorik Nonnekes, Lars B Oude Nijhuis, Alexander C H Geurts, Bastiaan R Bloem, Vivian Weerdesteyn
In this study, we investigated the effect of dopaminergic medication on reactive stepping responses to forward and backward balance perturbations in patients with moderately severe Parkinson's disease (PD). Twelve PD patients, Hoehn and Yahr stage ranging from 2 to 3, and 15 healthy controls were exposed to multidirectional translational stance perturbations on a moveable platform. Perturbations were unpredictable in terms of amplitude, timing and direction. Patients were tested in the medication ON and OFF (at least 12 h of dopaminergic medication withdrawal) state on two separate days...
December 2014: Journal of Neurology
Elizabeth L Inness, Avril Mansfield, Bimal Lakhani, Mark Bayley, William E McIlroy
BACKGROUND: Individuals with stroke are at increased risk for falls soon after hospital discharge. The ability to react to a balance perturbation, specifically with a rapid step, is critical to maintain balance and prevent falls. OBJECTIVE: The purpose of the study was to determine the prevalence of impaired reactive stepping responses in an ambulatory group of patients with stroke who were preparing for discharge from inpatient rehabilitation and the relationship to patient performance on commonly used clinical measures of balance, mobility, and lower limb impairment...
December 2014: Physical Therapy
Christopher P Carty, Neil J Cronin, Deanne Nicholson, Glen A Lichtwark, Peter M Mills, Graham Kerr, Andrew G Cresswell, Rod S Barrett
BACKGROUND: a fall occurs when an individual experiences a loss of balance from which they are unable to recover. Assessment of balance recovery ability in older adults may therefore help to identify individuals at risk of falls. The purpose of this 12-month prospective study was to assess whether the ability to recover from a forward loss of balance with a single step across a range of lean magnitudes was predictive of falls. METHODS: two hundred and one community-dwelling older adults, aged 65-90 years, underwent baseline testing of sensori-motor function and balance recovery ability followed by 12-month prospective falls evaluation...
January 2015: Age and Ageing
S Criado, A T Soltermann, N A García
The effect of the substitution pattern on the kinetics of the Type II (O2((1)Δg)-mediated) dye-sensitized photooxidation of a series of nine tyrosine derivatives was investigated. Overall (kt) and reactive (kr) rate constants for the interaction of the excited oxygen species with the amino acid derivatives were determined. A parallel study on solvent and pH effects was carried out.The presence of different substituents in nuclear positions or in the amino acid side chain greatly affect the photooxidation rates...
December 1995: Amino Acids
Arlan da Silva Gonçalves, Tanos Celmar Costa França, Melissa Soares Caetano, Teodorico Castro Ramalho
The present work describes a simple integrated Quantum Mechanics/Molecular Mechanics method developed to study the reactivation steps by pralidoxime (2-PAM) of acetylcholinesterase (AChE) inhibited by the neurotoxic agent Tabun. The method was tested on an AChE model and showed to be able to corroborate most of the results obtained before, through a more complex and time-consuming methodology, proving to be suitable to this kind of mechanistic study at a lower computational cost.
2014: Journal of Biomolecular Structure & Dynamics
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