Exploring the Efficacy of a Set of Smart Devices for Postural Awareness for Workers in an Industrial Context: Protocol for a Single-Subject Experimental Design.

BACKGROUND: In manufacturing industries, tasks requiring poor posture, high repetition, and long duration commonly induce fatigue and lead to an increased risk of work-related musculoskeletal disorders. Smart devices assessing biomechanics and providing feedback to the worker for correction may be a successful way to increase postural awareness, reducing fatigue, and work-related musculoskeletal disorders. However, evidence in industrial settings is lacking. OBJECTIVE: This study protocol aims to explore the efficacy of a set of smart devices to detect malposture and increase postural awareness, reducing fatigue, and musculoskeletal disorders. METHODS: A longitudinal single-subject experimental design following the ABAB sequence will be developed in a manufacturing industry real context with 5 workers. A repetitive task of screw tightening of 5 screws in a standing position into a piece placed horizontally was selected. Workers will be assessed in 4 moments per shift (10 minutes after the beginning of the shift, 10 minutes before and after the break, and 10 minutes before the end of the shift) in 5 nonconsecutive days. The primary outcomes are fatigue, assessed by electromyography, and musculoskeletal symptoms assessed by the Nordic Musculoskeletal Questionnaire. Secondary outcomes include perceived effort (Borg perceived exertion scale); range of motion of the main joints in the upper body, speed, acceleration, and deceleration assessed by motion analysis; risk stratification of range of motion; and cycle duration in minutes. Structured visual analysis techniques will be conducted to observe the effects of the intervention. Results for each variable of interest will be compared among the different time points of the work shift and longitudinally considering each assessment day as a time point. RESULTS: Enrollment for the study will start in April 2023. Results are expected to be available still in the first semester of 2023. It is expected that the use of the smart system will reduce malposture, fatigue, and consequently, work-related musculoskeletal pain and disorders. CONCLUSIONS: This proposed study will explore a strategy to increase postural awareness in industrial manufacturing workers who do repetitive tasks, using smart wearables that provide real-time feedback about biomechanics. Results would showcase a novel approach for improving self-awareness of risk for work-related musculoskeletal disorders for these workers providing an evidence base support for the use of such devices. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/43637.

Antibacterial and hemostatic capacities of cellulose nanocrystalline-reinforced poly(vinyl alcohol) electrospun mats doped with Tiger 17 and pexiganan peptides for prospective wound healing applications.

Infection is a major issue in chronic wound care. Different dressings have been developed to prevent microbial propagation, but an effective, all-in-one (cytocompatible, antimicrobial and promoter of healing) solution is still to be uncovered. In this research, polyvinyl alcohol (PVA) nanofibrous mats reinforced with cellulose nanocrystal (CNC), at 10 and 20% v/v ratios, were produced by electrospinning, crosslinked with glutaraldehyde vapor and doped with specialized peptides. Crosslinking increased the mats' fiber diameters but maintained their bead-free morphology. Miscibility between polymers was confirmed by Fourier-transform infrared spectroscopy and thermal evaluations. Despite the incorporation of CNC having reduced the mats' mechanical performance, it improved the mats' surface energy and its structural stability over time. Pexiganan with an extra cysteine group was functionalized onto the mats via hydroxyl- polyethylene glycol 2-maleimide, while Tiger 17 was physisorbed to preserve its cyclic conformation. Antimicrobial assessments demonstrated the peptide-doped mat's effectiveness against Staphylococcus aureus and Pseudomonas aeruginosa; pexiganan contributed mostly for such outcome. Tiger 17 showed excellent capacity in accelerating clotting. Cytocompatibility evaluations attested to these mats' safety. C90/10 PVA/CNC mats were deemed the most effective from the tested group and, thus, a potentially effective option for chronic wound treatments.

Osteosynthesis Metal Plate System for Bone Fixation Using Bicortical Screws: Numerical-Experimental Characterization.

This study reports the numerical and experimental characterization of a standard immobilization system currently being used to treat simple oblique bone fractures of femoral diaphyses. The procedure focuses on the assessment of the mechanical behavior of a bone stabilized with a dynamic compression plate (DCP) in a neutralization function, associated to a lag screw, fastened with surgical screws. The non-linear behavior of cortical bone tissue was revealed through four-point bending tests, from which damage initiation and propagation occurred. Since screw loosening was visible during the loading process, damage parameters were measured experimentally in independent pull-out tests. A realistic numerical model of the DCP-femur setup was constructed, combining the evaluated damage parameters and contact pairs. A mixed-mode (I+II) trapezoidal damage law was employed to mimic the mechanical behavior of both the screw-bone interface and bone fractures. The numerical model replicated the global behavior observed experimentally, which was visible by the initial stiffness and the ability to preview the first loading peak, and bone crack satisfactorily.

Thermal, Mechanical and Chemical Analysis of Poly(vinyl alcohol) Multifilament and Braided Yarns.

Poly(vinyl alcohol) (PVA) in multifilament and braided yarns (BY) forms presents great potential for the design of numerous applications. However, such solutions fail to accomplish their requirements if the chemical and thermomechanical behaviour is not sufficiently known. Hence, a comprehensive characterisation of PVA multifilament and three BY architectures (6, 8, and 10 yarns) was performed involving the application of several techniques to evaluate the morphological, chemical, thermal, and mechanical features of those structures. Scanning electron microscopy (SEM) was used to reveal structural and morphological information. Differential thermal analysis (DTA) pointed out the glass transition temperature of PVA at 76 °C and the corresponding crystalline melting point at 210 °C. PVA BY exhibited higher tensile strength under monotonic quasi-static loading in comparison to their multifilament forms. Creep tests demonstrated that 6BY structures present the most deformable behaviour, while 8BY structures are the least deformable. Relaxation tests showed that 8BY architecture presents a more expressive variation of tensile stress, while 10BY offered the least. Dynamic mechanical analysis (DMA) revealed storage and loss moduli curves with similar transition peaks for the tested structures, except for the 10BY. Storage modulus is always four to six times higher than the loss modulus.

Middle Vault Changes After Humpectomy by Spare Roof Technique Versus Component Dorsal Hump Reduction.

Objectives: To compare the effect of two different humpectomy techniques in the internal nasal valve (INV) angle in human anatomic specimens. Methods: Seven human anatomic specimens (14 heminoses) were included. A strip of subdorsal septal cartilage was removed and, in each nose, the right side of the middle roof lied intact over and was sutured to the septal cartilage (spare roof technique [SRT]), whereas in the left side the upper lateral cartilage was folded and sutured to the septal cartilage (component dorsal hump reduction [CDHR]). The INV angle was measured pre- and postoperatively. Results: Mean age of the specimens was 69.86 (60-80) years. Five were female. CDHR resulted in a mean change of +1.71 ± 3.12° (p = 0.197), +0.62 ± 6.89° (p = 0.817) and +6.97 ± 6.84° (p = 0.036) after resection of 2, 4, and 6 mm of septal cartilage, respectively. SRT resulted in a mean change of +1.27 ± 2.37° (p = 0.207), +6.89 ± 1.19° (p < 0.001), and +12.55 ± 1.79° (p < 0.001) after resection of 2, 4, and 6 mm of septal cartilage, respectively. In SRT, the amount of septal cartilage resection presented a significant correlation with change in INV angle (r = 0.813, p < 0.001). Conclusions: In this human anatomic study, SRT significantly increased INV angle.

Spare Roof Technique Versus Component Dorsal Hump Reduction: A Randomized Prospective Study in 250 Primary Rhinoplasties, Aesthetic and Functional Outcomes.

BACKGROUND: Most Caucasian aesthetic rhinoplasty patients complain about having a noticeable hump in profile view. Taking the integrity of the middle vault into consideration, there are 2 ways to dehump a nose: the structured technique and the preservation technique. OBJECTIVES: The aim of this study was to compare the aesthetic and functional outcomes of 2 reduction rhinoplasty techniques. METHODS: We performed a prospective, randomized, interventional, and longitudinal study on 250 patients randomly divided into 2 groups: the component dorsal hump reduction group (CDRg) (n = 125) and the spare roof technique group (SRTg) (n = 125). We utilized the Utrecht Questionnaire for Outcome Assessment in Aesthetic Rhinoplasty. Patients answered the questionnaire before the surgery, and at 3 and 12 months after surgery. In addition, we utilized a visual analog scale (VAS) to score nasal patency for each side. RESULTS: Analyses of the preoperative and postoperative aesthetic VAS scores showed a significant improvement in both groups, from 3.66 to 7.00 (at 3 months) to 7.35 (at 12 months) in the CDRg, and from 3.81 to 8.14 (at 3 months) to 8.45 (at 12 months) in the SRTg. Analyses of postoperative means of aesthetic VAS scores showed a significant improvement in both groups over time. However, aesthetic improvement was higher in the SRTg than in the CDRg at both 3 (P < 0.001) and 12 months (P < 0.001) postsurgery. Analyses of the mean functional VAS scores showed a significant improvement with both techniques, with a better result for the SRTg. CONCLUSIONS: The SRT is a reliable technique that can help deliver consistently better aesthetic and functional results than CDR for reduction rhinoplasty in Caucasian patients with a dorsal hump.

Thermo-Mechanical Behaviour of Human Nasal Cartilage.

The aim of this study was to undergo a comprehensive analysis of the thermo-mechanical properties of nasal cartilages for the future design of a composite polymeric material to be used in human nose reconstruction surgery. A thermal and dynamic mechanical analysis (DMA) in tension and compression modes within the ranges 1 to 20 Hz and 30 °C to 250 °C was performed on human nasal cartilage. Differential scanning calorimetry (DSC), as well as characterization of the nasal septum (NS), upper lateral cartilages (ULC), and lower lateral cartilages (LLC) reveals the different nature of the binding water inside the studied specimens. Three peaks at 60-80 °C, 100-130 °C, and 200 °C were attributed to melting of the crystalline region of collagen matrix, water evaporation, and the strongly bound non-interstitial water in the cartilage and composite specimens, respectively. Thermogravimetric analysis (TGA) showed that the degradation of cartilage, composite, and subcutaneous tissue of the NS, ULC, and LLC take place in three thermal events (~37 °C, ~189 °C, and ~290 °C) showing that cartilage releases more water and more rapidly than the subcutaneous tissue. The water content of nasal cartilage was estimated to be 42 wt %. The results of the DMA analyses demonstrated that tensile mode is ruled by flow-independent behaviour produced by the time-dependent deformability of the solid cartilage matrix that is strongly frequency-dependent, showing an unstable crystalline region between 80-180 °C, an amorphous region at around 120 °C, and a clear glass transition point at 200 °C (780 kJ/mol). Instead, the unconfined compressive mode is clearly ruled by a flow-dependent process caused by the frictional force of the interstitial fluid that flows within the cartilage matrix resulting in higher stiffness (from 12 MPa at 1 Hz to 16 MPa at 20 Hz in storage modulus). The outcomes of this study will support the development of an artificial material to mimic the thermo-mechanical behaviour of the natural cartilage of the human nose.