Mechanical lifting energy consumption in work activities designed by means of the "revised NIOSH lifting equation"\u80\u9d

The aims of the present work were: to calculate lifting energy consumption (LEC) in work activities designed to have a growing lifting index (LI) by means of revised NIOSH lifting equation; to evaluate the relationship between LEC and forces at the L5-S1 joint. The kinematic and kinetic data of 20 workers were recorded during the execution of lifting tasks in three conditions. We computed kinetic, potential and mechanical energy and the corresponding LEC by considering three different centers of mass of: 1) the load (CoML); 2) the multi-segment upper body model and load together (CoMUpp+L); 3) the whole body and load together (CoMTot). We also estimated compression and shear forces. Results shows that LEC calculated for CoMUpp+L and CoMTot grew significantly with the LI and that all the lifting condition pairs are discriminated. The correlation analysis highlighted a relationship between LEC and forces that determine injuries at the L5-S1 joint

sEMG and Postural Analysis for Biomechanical Risk Assessment in a Banknotes Printing Process

The purpose of this paper is to assess the biomechanical overload risk of some tasks that are typical of the printing industry, by means of surface electromyography and postural analysis software. In the first task of manual loading, muscle activation percentage duration of the Bicepses and Tricepses were similar for similar duty cycles. The Erector Spinae muscles had higher %MVC sustained for a greater percentage of the duty cycle. In the second task of aeration and transfer, Bicepses were activated for most of the duty cycle with a low %MVC between 0 and 5%. Differently, Triceps and Erector Spinae muscles had muscle activations with higher %MVC and higher percentage duration. In the third task, the muscular activity achieved the highest values in the Bicepses, while the activity of the Erector Spinae and Triceps muscles was less significant. Finally, in the fourth task, the compressive force values at the L5/S1 level found by 3DSSPP software ranged from 1072 N to 1863 N. Still at the L5/S1 level, shear forces ranged from 263 N to 310 N. In the observed conditions, the used methods found no significant biomechanical overload risk in the studied tasks. The %MVC values within the cycle were all below the threshold proposed by ACGIH. The force values at level L5/S1 estimated with 3DSSPP software were also less than the 3400 N threshold limit value proposed by NIOSH for compressive forces and less than the 700 N limit proposed for shear forces by Gallagher in his review. One of the observed activities at a faster working pace could increase the biomechanical risk. This is the case of the manual loading of the offset printing machine. In fact, the sheet board with the sheets to be loaded was positioned frontally to the printing machine loading area, thus forcing the operator to a 180° rotation. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG

Selective reorienting response of the left hemisphere to invalid visual targets in the right side of space: relevance for the spatial neglect syndrome

In humans, damage in the right hemisphere often provokes the striking inability to attend the left side of space, i.e. left spatial neglect. For years the leading hypothesis for the higher epidemiological incidence of left over right spatial neglect has been that the right hemisphere can orient attention to both sides of space while the left hemisphere only to the right side. Because of this hemispheric specialization, patients with lesion in the left hemisphere do not usually suffer right spatial neglect. Though comprehensive and very influential, to date, this explanation only found clear support in a MEG investigation into stimulus driven shifts of auditory attention. In contrast, no evidence for the same hypothesis was ever gathered from studies of visual attention run with behavioral paradigms that have importantly influenced the interpretation and modeling of attentional deficits in left spatial neglect. Here we report the first fMRI evidence directly supporting this long-standing hypothesis on the hemispheric lateralisation of mechanisms regulating orienting of spatial attention in the human brain. By demonstrating that the left hemisphere selectively reorients attention to invalidly cued visual targets in the right side of space we provide a more comprehensive account for deficits of spatial attention suffered by right brain damaged patients with left unilateral neglect

Wearable Monitoring Devices for Biomechanical Risk Assessment at Work: Current Status and Future Challenges—A Systematic Review

Background: In order to reduce the risk of work-related musculoskeletal disorders (WMSDs) several methods have been developed, accepted by the international literature and used in the workplace. The purpose of this systematic review was to describe recent implementations of wearable sensors for quantitative instrumental-based biomechanical risk assessments in prevention of WMSDs. Methods: Articles written until 7 May 2018 were selected from PubMed, Scopus, Google Scholar and Web of Science using specific keywords. Results: Instrumental approaches based on inertial measurement units and sEMG sensors have been used for direct evaluations to classify lifting tasks into low and high risk categories. Wearable sensors have also been used for direct instrumental evaluations in handling of low loads at high frequency activities by using the local myoelectric manifestation of muscle fatigue estimation. In the field of the rating of standard methods, on-body wireless sensors network-based approaches for real-time ergonomic assessment in industrial manufacturing have been proposed. Conclusions: Few studies foresee the use of wearable technologies for biomechanical risk assessment although the requirement to obtain increasingly quantitative evaluations, the recent miniaturization process and the need to follow a constantly evolving manual handling scenario is prompting their use

Erratum: Alberto, R. et al., Wearable Monitoring Devices for Biomechanical Risk Assessment at Work: Current Status and Future Challenges—A Systematic Review. <em>Int. J. Environ. Res. Public Health</em> 2018, 15, 2001

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The response of the left ventral attentional system to invalid targets and its implication for the spatial neglect syndrome : a multivariate fMRI investigation

In humans, invalid visual targets that mismatch spatial expectations induced by attentional cues are considered to selectively engage a right hemispheric "reorienting" network that includes the temporal parietal junction (TPJ), the inferior frontal gyrus (IFG), and the medial frontal gyrus (MFG). However, recent findings suggest that this hemispheric dominance is not absolute and that it is rather observed because the TPJ and IFG areas in the left hemisphere are engaged both by invalid and valid cued targets. Because of this, the BOLD response of the left hemisphere to invalid targets is usually cancelled out by the standard "invalid versus valid" contrast used in functional magnetic resonance imaging investigations of spatial attention. Here, we used multivariate pattern recognition analysis (MVPA) to gain finer insight into the role played by the left TPJ and IFG in reorienting to invalid targets. We found that in left TPJ and IFG blood oxygen level-dependent (BOLD) responses to invalid and valid targets were associated to different patterns of neural activity, possibly reflecting the presence of functionally distinct neuronal populations. Pattern segregation was significant at group level, it was present in almost all of the participants to the study and was observed both for targets in the left and right side of space. A control whole-brain MVPA ("Searchlight" analysis) confirmed the results obtained in predefined regions of interest and highlighted that also other areas, that is, superior parietal and frontal-polar cortex, show different patterns of BOLD response to valid and invalid targets. These results confirm and expand previous evidence highlighting the involvement of the left hemisphere in reorienting of visual attention (Doricchi et al. 2010; Dragone et al. 2015). These findings suggest that asymmetrical reorienting deficits suffered by right brain damaged patients with left spatial neglect, who have severe impairments in contralesional reorienting and less severe impairments in ipsilesional reorienting, are due to preserved reorienting abilities in the intact left hemispher