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BACKGROUND: The sculpting craft must adopt awkward postures that lead to musculoskeletal disorders (MSDs). OBJECTIVE: This study investigated the prevalence of musculoskeletal discomfort (MD) and its associations with postural risk factors, demographics, and work characteristics among sculptors. They were determined the differences between MDs during the weeks of the study. METHODS: A longitudinal study was conducted; MD was investigated using the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ). Posture was assessed using the Rapid Upper Limb Assessment method (RULA). Multivariate logistic regression (MLR) models analyzed associations with different factors. ANOVA was used to test for differences in MD prevalence. RESULTS: The analysis included 585 responses by body region. The prevalence of MD was high in the lower and upper limbs among sculptors (67.6%), with the lower back, upper arm, neck, and knees being the four most affected regions. Gender (female) (OR = 2.15), marital status (married) (OR = 1.80), health risk (obesity), the dual of a secondary job (OR = 1.94), job stress (OR = 2.10), duration of work (OR = 2.01), and difficulty keeping up with work (OR = 2.00) were significant predictors contributing to the occurrence of MD in different body regions. Only shoulder MD prevalence showed significant differences between study weeks. CONCLUSIONS: Sculptors suffer from MD. Demographic and work characteristic factors influence MD prevalence. Postural training, improved adaptation of work organization, and intervention guidance on ergonomic risks may reduce the prevalence of MD and the risk of MSDs in this population.

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We investigated the possible adsorption of each of the main building blocks of spider silk: alanine, glycine, leucine, and proline. This knowledge could help develop new biocompatible materials and favors the creation of new biosensors. We used ab initio density functional theory methods to study the variations in the optical absorption, reflectivity, and band structure of a modified graphene surface interacting with these four molecules. Four modification cases were considered: graphene with vacancies at 5.55% and fluorine, nitrogen, or oxygen doping, also at 5.55%. We found that, among the cases considered, graphene with vacancies is the best candidate to develop optical biosensors to detect C=O amide and differentiate glycine and leucine from alanine and proline in the visible spectrum region. Finally, from the projected density of states, the main changes occur at deep energies. Thus, all modified graphene's electronic energy band structure undergoes only tiny changes when interacting with amino acids.

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Amaranth has many interesting features, both nutritional and otherwise, that make it attractive as a food crop. Plants grown in greenhouses have higher yields but lower nutritional value compared to those grown in open fields. This prompted an interest in studying viable elicitors for the production of amaranth. Small hydrogen peroxide (H2O2) concentrations for foliar spraying from 0 to 18 mM have been used in greenhouse amaranth cultivation. The objective of this work was to evaluate the effect of foliar application of H2O2 megadoses on growth parameters, total phenolic compounds, condensed tannins, anthocyanins, and the antioxidant capacity of leaves and seeds of amaranth grown in a greenhouse setting. The seed of the Amaranthus hypochondriacus L. species was used. The concentrations of H2O2 analyzed were 0, 125, 250 and 400 mM, with 11 applications throughout the growing cycle. The variable data were subjected to an analysis of variance (ANOVA), followed by a Tukey's post hoc test (95% CI, p < 0.05). The results on chlorophyll, growth parameters and proximal chemical analysis showed no statistical difference between the control group versus the treatment groups. A greater number of favorable changes in the different variables studied were observed with the 125 mM H2O2 treatment, including the increase in antioxidant capacity measured by FRAP. The seed showed a considerable increase in TFC with all treatments and responded better to the 250 mM H2O2 treatment in the case of DPPH (an increase of 30%) and TPC (an increase of 44%). A 28% increase in anthocyanin content was observed with the treatment of 400 mM H2O2. The use of H2O2 may be an appropriate strategy to enhance the production of antioxidant compounds in amaranth without affecting growth or its basic proximal chemical composition. More studies are required in this regard.

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BACKGROUND: The effects of performing occupational tasks that demand physical and mental efforts in combined and simultaneous approaches are unknown, especially when pushing force is analyzed as a physical effort and solving arithmetic problems as a mental effort. OBJECTIVE: In this study, physical and mental demands were simulated in a lab environment to assess the workload. METHODS: Using a push force dynamometer, the maximum push force strength of each participant was recorded, and the physical demand was simulated exerting the push force in low, medium, and high levels. Mental demands were simulated solving arithmetic tasks in low, medium, and high levels. Two experimental conditions were defined: (1) task with combined physical and mental workload (performing physical demands first and mental demands after) and (2) task in a simultaneous way (performing both demands at the same time. NASA-TLX Traditional and RAW were applied to assess the workload. RESULTS: The time to complete the tasks was significantly longer in the combined than the simultaneous approach, and performance was significantly higher in the combined than the simultaneous tasks. CONCLUSION: The combined approach obtained better results than simultaneous and Traditional NASA-TLX presented a significantly higher level of global workload index than RAW.

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BACKGROUND: Today's work environments have high cognitive demands, and mental workload is one of the main causes of work stress, human errors, and accidents. While several mental workload studies have compared the mental workload perceived by groups of experienced participants to that perceived by novice groups, no comparisons have been made between the same individuals performing the same tasks at different times. OBJECTIVE: This work aims to compare NASA Task Load Index (NASA-TLX) to Workload Profile (WP) in terms of their sensitivity. The comparison considers the impact of experience and task differentiation in the same individual once a degree of experience has been developed in the execution of the same tasks. It also considers the acceptability and intrusivity of the techniques. METHODS: The sample consisted of 30 participants who performed four tasks in two sessions. The first session was performed when participants had no experience; the second session was performed after a time of practice. Mental workload was assessed after each session. Statistical methods were used to compare the results. RESULTS: The NASA-TLX proved to be more sensitive to experience, while the WP showed greater sensitivity to task differentiation. In addition, while both techniques featured a similar degree of intrusivity, the NASA-TLX received greater acceptability. CONCLUSION: The acceptability of WP is low due to the high complexity of its dimensions and clarifying explanations of these may be necessary to increase acceptability. Future research proposals should be expanded to consider mental workload when designing work environments in current manufacturing environments.

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A study was undertaken in which the handgrip strength in three arm positions above the shoulder was measured to compare handgrip strength when arm support is used and when it is not used. Grip forces were generated in pairs of flexion angles, corresponding to shoulder and elbow at 90°-90°, 135°-45° and 160°-20°. Thirty-two participants completed the present study; 23 men and nine women with a median age of 23.1 (SD ±3.6) years. A manual handgrip dynamometer (0-90 kg) and an adjustable angle arm support (AAAS) were used during the data collection. Two-way analysis of variance (ANOVA) for repeated measurements indicates a significant effect of the AAAS factor on the handgrip strength, as well as on the AAAS × angle interaction. However, there is no significant effect of the angle factor on the AAAS × angle interaction.

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Using structural relaxation calculations and first-principles molecular dynamics (FPMD), we performed numerical simulations to explore the interaction of a 2D MoS2 surface and a platinum atom, calculating the optical properties of the resulting material. We explored three initial positions for the interaction of the Pt atom and the pristine MoS2 surface, plus another position between Pt and the MoS2 surface with a sulfur vacancy VS. The surface absorbed the Pt atom in all cases considered, with absorption energies ranging from -2.77 eV to -5.83 eV. We calculated the optical properties and band structure of the two cases with the largest absorption energies (-3.45 eV and -5.83 eV). The pristine MoS2 is a semiconductor with a gap of around 1.80 eV. With the adsorption of the Pt atom (the -3.45 eV case), the material reduces its band gap to 0.95 eV. Additionally, the optical absorption in the visible range is greatly increased. The energy band structure of the 2D MoS2 with a sulfur vacancy VS shows a band gap of 0.74 eV, with consequent changes in its optical properties. After the adsorption of Pt atoms in the VS vacancy, the material has a band gap of 1.06 eV. In this case, the optical absorption in the visible range increases by about eight times. The reflectivity in the infrared range gets roughly doubled for both situations of the Pt-absorbed atom considered. Finally, we performed two FPMD runs at 300 K to test the stability of the cases with the lowest and highest absorption energies observed, confirming the qualitative results obtained with the structural relaxations.

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Using DFT simulations, we studied the interaction of a semifullerene C30 and a defected graphene layer. We obtained the C30 chemisorbs on the surface. We also found the adsorbed C30 chemisorbs, Li, Ti, or Pt, on its concave part. Thus, the resulting system (C30-graphene) is a graphene layer decorated with a metal-doped C30. The adsorption of the molecules depends on the shape of the base of the semifullerene and the dopant metal. The CO molecule adsorbed without dissociation in all cases. When the bottom is a pentagon, the adsorption occurs only with Ti as the dopant. It also adsorbs for a hexagon as the bottom with Pt as the dopant. The carbon dioxide molecule adsorbs in the two cases of base shape but only when lithium is the dopant. The adsorption occurs without dissociation. The ozone molecule adsorbs on both surfaces. When Ti or Pt are dopants, we found that the O3 molecule always dissociates into an oxygen molecule and an oxygen atom. When Li is the dopant, the O3 molecule adsorbs without dissociation. Methane did not adsorb in any case. Calculating the recovery time at 300 K, we found that the system may be a sensor in several instances.

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We performed ab initio numerical simulations with the density functional theory to investigate the variations in the band structure, optical absorption, and the reflectivity of vacancy-graphene doped with nitrogen, oxygen, and fluorine for different densities. We considered the density values 0.78%, 1.02%, 1.39%, 2.00%, 3.12%, 5.55%, and 12.5% for the vacancies and doping. In the infrared and visible ranges for all cases, vacancies included, there is a substantial increment in the absorption and reflectivity concerning graphene. The most significant changes are for fluorine and oxygen at a concentration of 12.5%.

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