Ergonomics evaluation through measurements of biomechanical parameters in real time has a great potential in reducing non-fatal occupational injuries, such as work-related musculoskeletal disorders. ...Assuming a correct posture guarantees the avoidance of high stress on the back and on the lower extremities, while an incorrect posture increases spinal stress. Here, we propose a solution for the recognition of postural patterns through wearable sensors and machine-learning algorithms fed with kinematic data. Twenty-six healthy subjects equipped with eight wireless inertial measurement units (IMUs) performed manual material handling tasks, such as lifting and releasing small loads, with two postural patterns: correctly and incorrectly. Measurements of kinematic parameters, such as the range of motion of lower limb and lumbosacral joints, along with the displacement of the trunk with respect to the pelvis, were estimated from IMU measurements through a biomechanical model. Statistical differences were found for all kinematic parameters between the correct and the incorrect postures (
< 0.01). Moreover, with the weight increase of load in the lifting task, changes in hip and trunk kinematics were observed (
< 0.01). To automatically identify the two postures, a supervised machine-learning algorithm, a support vector machine, was trained, and an accuracy of 99.4% (specificity of 100%) was reached by using the measurements of all kinematic parameters as features. Meanwhile, an accuracy of 76.9% (specificity of 76.9%) was reached by using the measurements of kinematic parameters related to the trunk body segment.
The estimation of the body's center of mass (CoM) trajectory is typically obtained using force platforms, or optoelectronic systems (OS), bounding the assessment inside a laboratory setting. The use ...of magneto-inertial measurement units (MIMUs) allows for more ecological evaluations, and previous studies proposed methods based on either a single sensor or a sensors' network. In this study, we compared the accuracy of two methods based on MIMUs. Body CoM was estimated during six postural tasks performed by 15 healthy subjects, using data collected by a single sensor on the pelvis (Strapdown Integration Method, SDI), and seven sensors on the pelvis and lower limbs (Biomechanical Model, BM). The accuracy of the two methods was compared in terms of RMSE and estimation of posturographic parameters, using an OS as reference. The RMSE of the SDI was lower in tasks with little or no oscillations, while the BM outperformed in tasks with greater CoM displacement. Moreover, higher correlation coefficients were obtained between the posturographic parameters obtained with the BM and the OS. Our findings showed that the estimation of CoM displacement based on MIMU was reasonably accurate, and the use of the inertial sensors network methods should be preferred to estimate the kinematic parameters.
In recent years, the use of inertial-based systems has been applied to remote rehabilitation, opening new perspectives for outpatient assessment. In this study, we assessed the accuracy and the ...concurrent validity of the angular measurements provided by an inertial-based device for rehabilitation with respect to the state-of-the-art system for motion tracking. Data were simultaneously collected with the two systems across a set of exercises for trunk and lower limbs, performed by 21 healthy participants. Additionally, the sensitivity of the inertial measurement unit (
)-based system to its malpositioning was assessed. Root mean square error (
) was used to explore the differences in the outputs of the two systems in terms of range of motion (
), and their agreement was assessed via Pearson's correlation coefficient (PCC) and Lin's concordance correlation coefficient (CCC). The results showed that the
-based system was able to assess upper-body and lower-limb kinematics with a mean error in general lower than 5° and that its measurements were moderately biased by its mispositioning. Although the system does not seem to be suitable for analysis requiring a high level of detail, the findings of this study support the application of the device in rehabilitation programs in unsupervised settings, providing reliable data to remotely monitor the progress of the rehabilitation pathway and change in patient's motor function.
Handling loads with a non-neutral posture induces overloading of the joint structures. Adopting incorrect postures during work can generate injuries. Ten healthy subjects were examined during lifting ...and repositioning different loads, while instrumented with a system of eight wearable Inertial Measurements Units. The tasks were performed in two conditions, safe and unsafe, when a load was lifted and then released. To detect differences between the two postures, kinematic parameters such as range of motion of joints and relative displacement between trunk and pelvis were estimated through a biomechanical model. Results demonstrated significant differences between the two postures for all kinematic parameters (p<0.05), except for medio-lateral component of the trunk-pelvis displacement. Only for the hip joints, a dependency on the increase in weight of the loads was found. Our results demonstrate feasibility of a solution for automatically detect incorrect and risky postures in load handling of workers.
Motion analysis is a fundamental methodology for examining upper-limb function. The objective of this study is to find a kinematic index for objectively evaluating the motor impairment caused by a ...stroke, during the execution of the Box and Block Test (BBT). We tracked trunk and upper limb motion during the test, using seven inertial measurement unit (IMU) sensors placed on trunk and upper limb of both sides. Two groups of subjects were considered. 14 healthy subjects, with a mean age of 47.9 ±18.3.10 stroke survivors, with a mean age of 53.6 ±19.8 and with different levels of motor disability (with an average value of 54.4 ±6.4 calculated with the Fugl-Meyer scale). Data acquired were processed through validated biomechanical models, dividing BBT task into three subphases: Reaching, Tranfser and Coming Back. Average hand velocity was calculated and compared among the dominant side of healthy subjects, the affected side, and the unaffected side of patients. The ANOVA test was used to study the differences between the two groups. As expected, the mean hand velocity of the affected side of the patients was found to be lower than both the dominant side of the control group and the unaffected side of patients (p<0.05). A correlation study was also conducted between mean velocity and the score that patients achieved in the BBT. For this study, however, the significance was not reached (p>0.1).
Excessive values of force on L5/S1 joint can cause work-related musculoskeletal disorders, such as low back pain. Currently, the reference solution for estimating such variables is the combination of ...optoelectronic system and force platform, used for calculating the bottom up inverse dynamics in laboratory settings. Here we propose and validate a novel, completely wearable solution, composed by twelve inertial measurement units and pressure insole sensors. We validate the wearable solution with respect to the output of the reference solution, with data collected simultaneously on a subject performing lifting and releasing tasks with two different loads. The results are encouraging towards the use of the wearable methodology, considering the great impact of such a solution in a real manufacturing scenario.
Individuals with patellofemoral pain syndrome present biomechanical alterations of lower limb kinematics and difficulties in postural control. Taping techniques like McConnell's were adopted to ...reduce pain and avert lower extremity injury, especially on the knee joint complex. Although the patellar taping appears to be an effective tool in reducing patellofemoral pain by stabilizing the patellofemoral joint, its immediate effects on balance, and trunk and lower limb kinematics are still not clear. The assessment of the immediate taping-induced biomechanical modifications on balance and kinematics could provide a deeper insight into the mechanical actions of the McConnell's. Nine healthy young adults (age: 29.1 ± 4.7 years) were equipped with eight wireless inertial measurement units placed on trunk and lower limbs. Participants were asked to perform the Star Excursion Balance Test (SEBT) and the Single Leg Squat (SLS) task in five different directions on a force plate. Kinematics of lumbosacral and lower limb joints, as well as balance indices such as spatiotemporal parameters of the center of pressure, were estimated with and without the McConnell taping. No mechanical effects were observed for spatiotemporal indices of the center of pressure and for all considered kinematic parameters, except for kinematics of the knee. Results demonstrated significant differences due to taping condition (p=0.01) for the knee joint in the SLS task. A similar trend was observed in SEBT. This interesting result highlights the instantaneous effect of McConnell taping on knee joint complex, without impairing any self-selected strategies adopted by healthy subjects.
Having thrived in Eurasia for 350,000 years Neandertals disappeared from the record around 40,000-37,000 years ago, after modern humans entered Europe. It was a complex process of population ...interactions that included cultural exchanges and admixture between Neandertals and dispersing groups of modern humans. In Europe Neandertals are always associated with the Mousterian while the Aurignacian is associated with modern humans only. The onset of the Aurignacian is preceded by "transitional" industries which show some similarities with the Mousterian but also contain modern tool forms. Information on these industries is often incomplete or disputed and this is true of the Uluzzian. We present the results of taphonomic, typological and technological analyses of two Uluzzian sites, Grotta La Fabbrica (Tuscany) and the newly discovered site of Colle Rotondo (Latium). Comparisons with Castelcivita and Grotta del Cavallo show that the Uluzzian is a coherent cultural unit lasting about five millennia, replaced by the Protoaurignacian before the eruption of the Campanian Ignimbrite. The lack of skeletal remains at our two sites and the controversy surrounding the stratigraphic position of modern human teeth at Cavallo makes it difficult to reach agreement about authorship of the Uluzzian, for which alternative hypotheses have been proposed. Pending the discovery of DNA or further human remains, these hypotheses can only be evaluated by archaeological arguments, i.e. evidence of continuities and discontinuities between the Uluzzian and the preceding and succeeding culture units in Italy. However, in the context of "transitional" industries with disputed dates for the arrival of modern humans in Europe, and considering the case of the Châtelperronian, an Upper Paleolithic industry made by Neandertals, typo-technology used as an indicator of hominin authorship has limited predictive value. We corroborate previous suggestions that the Middle-to-Upper Paleolithic transition occurred as steps of rapid changes and geographically uneven rates of spread.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A disintegrine and metalloproteinase 10 (ADAM10) is implicated in synaptic function through its interaction with postsynaptic receptors and adhesion molecules. Here, we report that levels of active ...ADAM10 are increased in Huntington's disease (HD) mouse cortices and striata and in human postmortem caudate. We show that, in the presence of polyglutamine-expanded (polyQ-expanded) huntingtin (HTT), ADAM10 accumulates at the postsynaptic densities (PSDs) and causes excessive cleavage of the synaptic protein N-cadherin (N-CAD). This aberrant phenotype is also detected in neurons from HD patients where it can be reverted by selective silencing of mutant HTT. Consistently, ex vivo delivery of an ADAM10 synthetic inhibitor reduces N-CAD proteolysis and corrects electrophysiological alterations in striatal medium-sized spiny neurons (MSNs) of 2 HD mouse models. Moreover, we show that heterozygous conditional deletion of ADAM10 or delivery of a competitive TAT-Pro-ADAM10709-729 peptide in R6/2 mice prevents N-CAD proteolysis and ameliorates cognitive deficits in the mice. Reduction in synapse loss was also found in R6/2 mice conditionally deleted for ADAM10. Taken together, these results point to a detrimental role of hyperactive ADAM10 at the HD synapse and provide preclinical evidence of the therapeutic potential of ADAM10 inhibition in HD.
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