A New Postural Force Production Index to Assess Propulsion Effectiveness During Handcycling

The aim of this study was to propose a new index called Postural Force Production Index (PFPI) for evaluating the force production during handcycling. For a given posture, it assesses the force generation capacity in all Cartesian directions by linking the joint configuration to the effective force applied on the handgrips. Its purpose is to give insight into the force pattern of handcycling users, and could be used as ergonomic index. The PFPI is based on the force ellipsoid, which belongs to the class of manipulability indices and represents the overall force production capabilities at the hand in all Cartesian directions from unit joint torques. The kinematics and kinetics of the arm were recorded during a 1-min exercise test on a handcycle at 70 revolutions per minute performed by one paraplegic expert in handcycling. The PFPI values were compared with the Fraction Effective Force (FEF), which is classically associated with the effectiveness of force application. The results showed a correspondence in the propulsion cycle between FEF peaks and the most favorable postures to produce a force tangential to the crank rotation (PFPI). This preliminary study opens a promising way to study patterns of force production in the framework of handcycling movement analysis.

Download Full-text

Hydrogen Passivation Kinetics of Si Nanocrystals in SiO2

MRS Proceedings ◽

10.1557/proc-770-i4.6 ◽

2003 ◽

Vol 770 ◽

Author(s):

Andrew R. Wilkinson ◽

Robert G. Elliman

Keyword(s):

Reaction Kinetics ◽

Activation Energies ◽

Hydrogen Passivation ◽

Time Resolved ◽

Luminescence Efficiency ◽

Si Nanocrystals ◽

Preliminary Study ◽

Kinetics Of ◽

Insight Into

AbstractHydrogen passivation of non-radiative defects increases the luminescence intensity from silicon nanocrystals. In this study, photoluminescence (PL) and time-resolved PL were used to investigate the chemical kinetics of the hydrogen passivation process. Isochronal and isothermal annealing sequences were used to determine the reaction kinetics for the absorption and desorption of hydrogen, using the generalised consistent simple thermal (GST) model proposed by Stesmans for Pb defects at planar Si/SiO2 interfaces. This included determination of the activation energies and rate constants for the forward and reverse reactions as well as the associated spread in activation energies. The reaction kinetics determined from such measurements were found to be in excellent agreement with those for the passivation of Pb defects at planar Si/SiO2 interfaces, suggesting the nanocrystal emission process is also limited by such defects. These results provide useful model data as well as insight into the processing conditions needed to achieve optimum passivation in H2. As an extension to the work, a preliminary study into passivation by atomic hydrogen was pursued via a post-metallization Al anneal (alneal). A considerable gain in luminescence efficiency was achieved over the previously optimised passivation in H2.

Download Full-text

Kinematics and Kinetics of the Racket-Arm during the Soft-Tennis Smash under Match Conditions

Journal of Applied Biomechanics ◽

10.1123/jab.21.4.334 ◽

2005 ◽

Vol 21 (4) ◽

pp. 334-347 ◽

Cited By ~ 4

Author(s):

Hirofumi Ida ◽

Seiji Kusubori ◽

Motonobu Ishii

Keyword(s):

Time Pressure ◽

Swing Phase ◽

Joint Torque ◽

Elbow Extension ◽

Competitive Situation ◽

Match Play ◽

Joint Torques ◽

Tennis Serve ◽

Kinetics Of ◽

Kinematics And Kinetics

The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the soft-tennis smash during match rallies, and (b) assess the characteristics of this smash vs. the laboratory-simulated smash of our previous study. In the current study we recorded soft-tennis smash motions during match play of the 3rd East Asian Games. Racket-arm anatomical joint angular velocity and anatomical joint torque were calculated from 3-D coordinate data of 13 collected motions obtained using the direct linear transformation procedure. The results showed that most of the maximum values of the anatomical joint torques were qualitatively smaller than those of the tennis serve. Peak elbow extension, shoulder internal rotation, and elbow varus torques in match play were significantly greater than values reported for laboratory-simulated conditions. The greater forward swing torques did not result in significantly different racket head velocity, possibly because there was a significantly shorter forward swing phase in match conditions. In particular, a clear peak of the elbow extension torque during the forward swing phase was the most characteristic pattern in the smashes under match conditions, for it was 160% greater than laboratory-simulated conditions. These results supported our hypothesis that racket-arm kinematic and kinetic characteristics of the smash under match conditions differ from those under laboratory-simulated conditions. Possible explanations include the time-pressure conditions of the competitive situation in a match, and the Hawthorne effect (Hudson et al., 1986), both of which alter performance between match conditions and laboratory-simulated conditions.

Download Full-text

Kinetics of Accelerated Vulcanization—III N-Cyclohexyl-Benzothiazole-2-Sulfenamide Accelerated Sulfur Vulcanization of Rubbers

Rubber Chemistry and Technology ◽

10.5254/1.3539304 ◽

1969 ◽

Vol 42 (5) ◽

pp. 1366-1382 ◽

Cited By ~ 5

Author(s):

S. K. Bhatnagar ◽

S. Banerjee

Keyword(s):

Zinc Oxide ◽

Stearic Acid ◽

Zinc Sulfide ◽

Cross Link ◽

Influence Of Temperature ◽

Sulfur Vulcanization ◽

Preliminary Study ◽

Kinetics Of ◽

Link Formation ◽

Insight Into

Abstract Sulfenamide type of accelerators are well known for their outstanding processing safety combined with ultra-strong accelerating activity resulting in superior quality vulcanizates. Sulfenamides derived from different amines afford varying degrees of scorch delay and accelerating activity. Since there is no unanimity on the chemistry involved in this type of accelerated vulcanization, a preliminary study has been carried out to gain some insight into the mechanistic scheme. The present paper contains reports on the effects of varying concentrations of N-cyclohexyl-benzothiazole-2-sulfenamide (CBS) on the rate of free sulfur decrease and cross-link formation as well as zinc sulfide formation—whenever it occurs—both in the absence and presence of zinc oxide and of zinc oxide and stearic acid. The influence of temperature has also been investigated.

Download Full-text

Effects of body mass and sex on kinematics and kinetics of the lower extremity during stair ascent and descent in older adults

Sports Medicine and Health Science ◽

10.1016/j.smhs.2021.06.001 ◽

2021 ◽

Author(s):

Nok-Hin Law ◽

Jing Xian Li ◽

Nok-Yeung Law ◽

Daniel Varin ◽

Mario Lamontagne

Keyword(s):

Older Adults ◽

Lower Extremity ◽

Body Mass ◽

Stair Ascent ◽

Kinetics Of ◽

Kinematics And Kinetics

Download Full-text

Taking time with the tough-construction

Journal of Linguistics ◽

10.1017/s002222672100013x ◽

2021 ◽

pp. 1-36

Author(s):

JOHN GLUCKMAN

Keyword(s):

Movement Analysis ◽

Main Clause ◽

Syntactic Analysis ◽

English Syntax ◽

Insight Into ◽

The Way

I provide a syntactic analysis of the take-time construction (It took an hour to complete the test). The investigation provides insight into well-known issues concerning the related tough-construction. Using a battery of standard syntactic diagnostics, I conclude that the take-time construction and the tough-construction require a predication analysis of the antecedent-gap chain, not a movement analysis. I also conclude that the nonfinite clause is in a modificational relationship with the main clause predicate, not a selectional relationship. Broadly, this study expands the class of tough-constructions, illustrating crucial variation among predicates, and pointing the way to a unified analysis. The investigation also reveals undiscussed aspects of English syntax, including the fact that English has a high applicative position.

Download Full-text

Rapid systemic surge of IL-33 after severe human trauma: a prospective observational study

Molecular Medicine ◽

10.1186/s10020-021-00288-1 ◽

2021 ◽

Vol 27 (1) ◽

Author(s):

Olav Sundnes ◽

William Ottestad ◽

Camilla Schjalm ◽

Peter Lundbäck ◽

Lars la Cour Poulsen ◽

...

Keyword(s):

High Resolution ◽

Prospective Observational Study ◽

Tissue Injury ◽

Trauma Patients ◽

Decoy Receptor ◽

Interleukin 33 ◽

Injured Patients ◽

First Time ◽

Kinetics Of ◽

Insight Into

Abstract Background Alarmins are considered proximal mediators of the immune response after tissue injury. Understanding their biology could pave the way for development of new therapeutic targets and biomarkers in human disease, including multiple trauma. In this study we explored high-resolution concentration kinetics of the alarmin interleukin-33 (IL-33) early after human trauma. Methods Plasma samples were serially collected from 136 trauma patients immediately after hospital admission, 2, 4, 6, and 8 h thereafter, and every morning in the ICU. Levels of IL-33 and its decoy receptor sST2 were measured by immunoassays. Results We observed a rapid and transient surge of IL-33 in a subset of critically injured patients. These patients had more widespread tissue injuries and a greater degree of early coagulopathy. IL-33 half-life (t1/2) was 1.4 h (95% CI 1.2–1.6). sST2 displayed a distinctly different pattern with low initial levels but massive increase at later time points. Conclusions We describe for the first time early high-resolution IL-33 concentration kinetics in individual patients after trauma and correlate systemic IL-33 release to clinical data. These findings provide insight into a potentially important axis of danger signaling in humans.

Download Full-text

Kinematics and kinetics of the bench-press and bench-pull exercises in a strength-trained sporting population

Sports Biomechanics ◽

10.1080/14763140903229484 ◽

2009 ◽

Vol 8 (3) ◽

pp. 245-254 ◽

Cited By ~ 17

Author(s):

Simon N. Pearson ◽

John B. Cronin ◽

Patria A. Hume ◽

David Slyfield

Keyword(s):

Bench Press ◽

Kinetics Of ◽

Kinematics And Kinetics

Download Full-text

Simulation of Folding Kinetics for Aligned RNAs

Genes ◽

10.3390/genes12030347 ◽

2021 ◽

Vol 12 (3) ◽

pp. 347

Author(s):

Jiabin Huang ◽

Björn Voß

Keyword(s):

Evolutionary Conservation ◽

Folding Kinetics ◽

New Approach ◽

Computational Approaches ◽

Reasonable Time ◽

Valuable Method ◽

Kinetics Of ◽

Insight Into ◽

Folding Space ◽

Standing Problem

Studying the folding kinetics of an RNA can provide insight into its function and is thus a valuable method for RNA analyses. Computational approaches to the simulation of folding kinetics suffer from the exponentially large folding space that needs to be evaluated. Here, we present a new approach that combines structure abstraction with evolutionary conservation to restrict the analysis to common parts of folding spaces of related RNAs. The resulting algorithm can recapitulate the folding kinetics known for single RNAs and is able to analyse even long RNAs in reasonable time. Our program RNAliHiKinetics is the first algorithm for the simulation of consensus folding kinetics and addresses a long-standing problem in a new and unique way.

Download Full-text

Atomic-level insight into reasonable design of metal-based catalysts for hydrogen oxidation in alkaline electrolytes

Energy & Environmental Science ◽

10.1039/d0ee03609a ◽

2021 ◽

Author(s):

Lulu An ◽

Xu Zhao ◽

Tonghui Zhao ◽

Deli Wang

Keyword(s):

Fuel Cell ◽

Anion Exchange ◽

Hydrogen Oxidation ◽

Anion Exchange Membrane ◽

Atomic Level ◽

Alkaline Electrolytes ◽

Exchange Membrane ◽

Kinetics Of ◽

Insight Into ◽

Hydrogen Utilization

Anion exchange membrane fuel cell (AEMFC) is becoming highly attractive for hydrogen utilization owing to the advantages of employing economic catalysts in alkaline electrolytes. Nevertheless, the kinetics of anodic hydrogen...

Download Full-text