Disturbance and recovery of trunk mechanical and neuromuscular behaviours following prolonged trunk flexion: influences of duration and external load on creep-induced effects

Trunk flexion results in adverse mechanical effects on the spine and is associated with a higher incidence of low back pain. To examine the effects of creep deformation on trunk behaviours, participants were exposed to full trunk flexion in several combinations of exposure duration and external load. Trunk mechanical and neuromuscular behaviours were obtained pre- and post-exposure and during recovery using sudden perturbations. Intrinsic trunk stiffness decreased with increasing flexion duration and in the presence of the external load. Recovery of intrinsic stiffness required more time than the exposure duration and was influenced by exposure duration. Reflexive trunk responses increased immediately following exposure but recovered quickly (～2.5 min). Alterations in reflexive trunk behaviour following creep deformation exposures may not provide adequate compensation to allow for complete recovery of concurrent reductions in intrinsic stiffness, which may increase the risk of injury due to spinal instability. STATEMENT OF RELEVANCE: An increased risk of low back injury may result from flexion-induced disturbances to trunk behaviours. Such effects, however, appear to depend on the type of flexion exposure, and have implications for the design of work involving trunk flexion.     

An overview of the welding technologies of CLAM steels for fusion application

China Low Activation Martensitic steel (CLAMs), a kind of RAFM steel with Chinese intellectual property rights, is considered as the primary structural material for the China-designed ITER test blanket module (TBM). As one of the key issues in the fabrication of the fusion reactor, the welding technologies of CLAMs are reviewed. Emphasis is placed on the weldability of CLAMs by different welding methods, and on the properties of as-welded and post-weld heat-treated joints. Recent highlights in research and development for the welding of CLAMs show that proper welding procedure could provide welds with adequate tensile strength but the welds exhibit lower impact toughness compared with the base metal. Post-weld heat treatment (PWHT) and the application of ultrasonic energy during TIG welding could dramatically improve impact toughness. Research also shows that welds in CLAMs have sufficient resistance to swelling under irradiation as well as suitable compatibility with liquid LiPb. The microstructure, mechanical and other physical properties of welds are significantly different from those of the base metal due to the complicated welding thermal cycle. The weld joint is the area most likely to fail one or more of the design requirements within the fusion reactor. Therefore significant additional research is necessary to ensure safe application of welded CLAM steel for fusion reactor construction.     

The continent ileostomy and the isolated ileal bladder

To study the mechanism of action by which droperidol exerts a negative chronotropic effect, 3 series of experiments were performed: a) on isolated right atria of rabbits, b) on the isolated vas deferens of guinea-pigs and c) by injecting the drug directly into the sinus node artery of anesthetized dogs. Isolated tissue results include: lack of cholinergic action or beta-adrenergic antagonism: a calcium ion flux interference could not be demonstrated. Alpha adrenergic antagonism of the drug (pA2) was ascertained in the vas deferens. Injections of droperidol in the sinus node artery caused a negative chrontropic effect proportional to the dose and arrest ensued with the largest dose followed by His escape rhythm. Droperidol could not inhibit isoproterenol or dopamine-induced tachycardia and showed similar negative chronotropism in vagotomized and atropinized dogs. Negative chronotropic effects of the drug appear to be caused by an exit blockade of sinus impulses.     

Immediate and delayed recall of words and pictures.

Examined free and serial recall of words and pictures associates in 3 experiments with 156 Ss. In immediate free recall, presentation of pictorial material increased only the secondary memory component of recall, relative to conditions involving presentation of verbal materials. No such facilitation occurred in immediate serial recall. In delayed recall tests, negative recency effects were obtained only for verbal materials, in both free and serial recall. Recency effects were either nonnegative or positive with pictures as to-be-remembered material. Results are discussed in terms of the locus of word-picture differences and the adequacy of verbal memory model explanations for them. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrochemical studies of ferrocene in a lithium ion conducting organic carbonate electrolyte

We carried out a detailed study of the kinetics of oxidation of ferrocene (Fc) to ferrocenium ion (Fc⁺) in the non-aqueous lithium ion conducting electrolyte composed of a solution of 1 M LiPF₆ in 1:1 EC:EMC solvent mixture. This study using cyclic (CV) and rotating disk electrode (RDE) voltammetry showed that the Fc⁰/Fc⁺ redox couple is reversible in this highly concentrated electrolyte. The ferrocene and ferrocenium ion diffusion coefficients (D) were calculated from these results. In addition, the electron transfer rate constant (k⁰) and the exchange current density for the oxidation of ferrocene were determined. A comparison of the kinetic data obtained from the two electrochemical techniques appears to show that the data from the RDE experiments are more reliable because they are collected under strict mass transport control. A Tafel slope of c.a. 79 mV/decade and a transfer coefficient α of 0.3 obtained from analysis of the RDE data for ferrocene oxidation suggest that the structure of the activated complex is closer to that of the oxidized specie due to strong interactions with the carbonate solvents. The experiments reported here are relevant to the study of redox reagents for the chemical overcharge protection of Li-ion batteries.     

A statistical, nonparametric methodology for document degradation model validation

Printing, photocopying, and scanning processes degrade the image quality of a document. Statistical models of these degradation processes are crucial for document image understanding research. In this paper, we present a statistical methodology that can be used to validate local degradation models. This method is based on a nonparametric, two-sample permutation test. Another standard statistical device, the power function, is then used to choose between algorithm variables such as distance functions. Since the validation and the power function procedures are independent of the model, they can be used to validate any other degradation model. A method for comparing any two models is also described. It uses p-values associated with the estimated models to select the model that is closer to the real world.