The NIOSH Lifting Equation is widely used to evaluate manual material handling tasks by identifying lifting risk through load reduction multipliers based on task geometry. However, while it provides a means of classifying risk, it does not estimate spinal forces and therefore cannot quantify the biomechanical load experienced at the lumbar spine. In contrast, biomechanical simulations can estimate spinal compression with high fidelity, but they require motion capture systems and specialized software that are not practical for most workplace assessments. This study aimed to bridge these approaches by developing a family of mixed-effect statistical models that predict L4/L5 spinal compression forces using the geometric parameters of the NIOSH framework combined with posture-specific biomechanical descriptors at peak-loading poses extracted from digital simulations. Data were aggregated from multiple experimental lifting studies in which standardized NIOSH parameters and corresponding spinal compression forces were obtained through validated digital human modeling. Mixed-effects regression was used to establish the relationship between task geometry, joint posture, load weight, and spinal compression. The resulting predictive equation demonstrated strong agreement with simulation-derived forces and effectively captured the contributions of subject, task and body positioning to the spinal compression force across diverse lifting tasks. Importantly, the variance structure of the model’s coefficients allows the contribution of risk to be attributed either to task-related factors or to subject-specific movement behaviors, reinforcing the safety relevance of the framework. Horizontal reach, vertical hand height, and load magnitude emerged as dominant predictors, with trunk posture providing additional explanatory power. The model offers ergonomists a practical, biomechanics-informed tool that extends the descriptive capacity of the NIOSH framework by enabling direct estimation of spinal compression forces without the need for full biomechanical simulations.

Lumbar shear forces are increasingly recognized as critical contributors to lower-back injury risk, yet most ergonomic assessment tools—most notably the Revised NIOSH Lifting Equation (RNLE)—do not directly estimate shear loading. This study develops and evaluates a family of linear mixed-effects regression models that statistically predict L4/L5 lumbar shear force exposure using traditional NIOSH lifting parameters combined with posture descriptors extracted from digital human models. A harmonized dataset of 106 peak-shear lifting postures was compiled from five controlled laboratory studies, with lumbar shear forces obtained from validated biomechanical simulations implemented in the Siemens JACK (Siemens software, Plano, TX, USA) platform. Twelve model formulations were examined, varying in fixed-effect structure and hierarchical random effects, to quantify how load magnitude, hand location, sex, and joint posture relate to simulated task-level anterior–posterior shear exposure at the lumbar spine. Across all models, load magnitude and horizontal reach emerged as the strongest and most stable predictors of shear exposure, reflecting their direct mechanical influence on anterior spinal loading. Hip and knee flexion provided substantial additional explanatory power, highlighting the role of whole-body posture strategy in modulating shear demand. Upper-limb posture and coupling quality exhibited minimal or inconsistent effects once load geometry and lower-body posture were accounted for. Random-effects analyses demonstrated that meaningful variability arises from individual movement strategies and task conditions, underscoring the necessity of mixed-effects modeling for representing hierarchical structure in lifting data. Parsimonious models incorporating subject-level random intercepts produced the most stable and interpretable coefficients while maintaining strong goodness-of-fit. Overall, the findings extend the NIOSH framework by identifying posture-dependent determinants of lumbar shear exposure and by demonstrating that simulated shear loading can be reliably predicted using ergonomically accessible task descriptors. The proposed models are intended as statistical predictors of task-level shear exposure that complement—rather than replace—comprehensive biomechanical simulations. This work provides a quantitative foundation for integrating shear-aware metrics into ergonomic risk assessment practices, supporting posture-informed screening of manual material-handling tasks in field and sensor-based applications.

Helicopter pilots are exposed to a wide range of vibration frequencies, primarily generated by engine and rotor dynamics. These vibrations, particularly within the 0.5–80 Hz range, pose significant risks to pilot health, including musculoskeletal injuries and fatigue. To mitigate these effects, vibration isolators are employed, with passive and active isolation systems offering different advantages. This study investigates the initial design and performance of a novel metal additive manufactured vibration isolator, optimized for placement under the pilot's seat in a rotorcraft simulator. The isolator was designed with key structural parameters including stiffness, coil dimensions, and material properties while maintaining a lightweight and durable form, with a primary goal of validating the additive manufacturing of a metallic isolator. Experimental corroboration was conducted by incorporating modifications to the Gannon Biomechanics Flight Simulator test stand (GBFS), comparing the novel isolator to an elastomeric isolator. Results demonstrate the successful fabrication of the initial additive isolator design. The additive isolator displayed a similar performance to the rubber isolator after being installed in the GBFS, though limitations on the current test rig and sensing configuration did not allow accurate characterization of the transmissibility. This research sets the groundwork for further development of a novel additive isolator and test facility.

Archery has increasingly captivated attention in its use for rehabilitation and physical education due to its adaptability for various abilities. However, this repetitive sport carries some injury risk in the shoulder, elbow, and back during the draw and release phases. While research often explores factors affecting shooting performance, limited studies have examined the interplay between gender-specific biomechanics and bow-related variables on lumbar stress and shooting mechanics. This study addresses this gap by leveraging the Xsens MVN Awinda motion capture system and JACK Siemens ergonomic software to analyze full-body movements of archers with different experience levels, bow types, and target placements. Thirteen subjects participated in this investigation, each equipped with standard gear. We analyzed their posture throughout the shooting sequence and the forces acting on their lower back. This innovative approach streamlines data collection and eliminates the need for extensive prototyping. Our findings highlight natural biomechanical adaptations between males and females when using bows of varying draw weights. Males generally exhibited greater consistency and stability, while females showed increased variability, particularly with heavier bows. This research establishes a foundation for ergonomic and reproducible archery techniques, enabling individualized training and performance optimization strategies.

Poly-lactic acid (PLA) is a synthetic polymer that has gained popularity as a scaffold due to well-established manufacturing processes, predictable biomaterial properties, and sustained therapeutic release rates. However, its drawbacks include weak mechanical parameters and reduced medicinal delivery efficacy after PLA degradation. The development of synthetic polymers that can release antibiotics and other medicines remains a top research priority. This study proposes a novel approach to produce PLA by converting Brewer’s spent grain (BSG) into lactic acid by bacterial fermentation followed by lactide ring polymerization with a metal catalyst. The elution properties of the PLA polymer are evaluated using modified Kirby–Bauer assays involving the antimicrobial chemotherapeutical, trimethoprim (TMP). Molded PLA polymer disks are impregnated with a known killing concentration of TMP, and the PLA is evaluated as a drug vehicle against TMP-sensitive Escherichia coli. This approach provides a practical means of assessing the polymer’s ability to release antimicrobials, which could be beneficial in exploring new drug-eluting synthetic polymer strategies. Overall, this study highlights the potential of using BSG waste materials to produce valuable biomaterials of medical value with the promise of expanded versatility of synthetic PLA polymers in the field of drug-impregnated tissue grafts.

Archery ranks among the sports with a high incidence of upper extremity injuries, particularly affecting the drawing shoulder and elbow, as well as inducing stress on the lower back. This study seeks to bridge the gap by integrating real-time human motion with biomechanical software to enhance the ergonomics of archers. Thirteen participants were involved in four tasks, using different bows with varied draw weights and shooting distances. Through the application of advanced integrative technology, this study highlights the distinct postures adopted by both males and females, which indicate the biomechanical differences between genders. Additionally, an analysis of the correlation between exposed spinal forces and these adopted postures provides insights into injury risk assessment during the key archery movements. The findings of this study have the potential to significantly enhance the application of training methodologies and the design of assistive devices. These improvements are geared towards mitigating injury risks and enhancing the overall performance of archers.

Some infants are born prematurely or with medical conditions that require them to stay in neonatal intensive care units (NICUs). Typically, these infants spend most of their time in an incubator as it provides a safe and controlled environment. At times, these infants will need to be transported via helicopter from one hospital to another, which exposes their already fragile bodies to higher levels of vibration. Helicopters, while advantageous for medical transport, generate substantial vibration due to rotor dynamics. Current models of incubators lack specific design for reducing vibrations. This project proposes a functional vibration damper that can be integrated into existing neonatal incubators, aiming to enhance infant safety during air transport. ANSYS modeling identified low-density polyethylene foam as an effective material for vibration reduction. Flight simulation tests demonstrated the 2" polyethylene mattress reduced vibrations at low amplitudes and frequencies, but challenges arose at higher values. The prototype addresses the critical need for reducing vibrations in neonatal incubators during air transport. While successful in initial tests, further extensive testing is required for potential implementation in the medical industry.

Introduction: Archers face a notable annual risk of injury attributed to the repetitive strain exerted on their upper body muscles and joints. This groundbreaking study marks the first utilization of real-time motion tracking combined with ergonomic analysis in archery research, eliminating the need for extensive equipment setups and streamlining data collection. Methods: Thirteen participants were involved, undertaking four tasks with varying draw weights of bows and target positions. Results: The precise recording of human movements revealed distinctive postures adopted by both genders across different tasks. Furthermore, an assessment of exposed spinal force and its correlation with anatomical variables was conducted, providing valuable insights into injury risks during archery performances.

The utility of brewery spent grain (BSG), a byproduct of the beer production process, for the synthesis of polyhydroxyalkanoates (PHAs), is a significant advancement towards sustainable and cost-effective biopolymer production. This paper reviews the upcycling potential of BSG as a substrate for PHA production, utilizing various biotechnological approaches to convert this abundant waste material into high-value biodegradable polymers. Through a comprehensive review of recent studies, we highlight the biochemical composition of BSG and its suitability for microbial fermentation processes. This research delves into different methodologies for PHA production from BSG, including the use of mixed microbial cultures (MMCs) for the synthesis of volatile fatty acids (VFAs), a critical precursor in PHA production, and solid-state fermentation (SSF) techniques. We also examine the optimization of process parameters such as pH, temperature, and microbial concentration through the application of the Doehlert design, revealing the intricate relationships between these factors and their impact on VFA profiles and PHA yields. Additionally, this paper discusses challenges and future perspectives for enhancing the efficiency and economic viability of PHA production from BSG. By harnessing the untapped potential of BSG, this research contributes to the development of a circular economy model, emphasizing waste valorization and the creation of sustainable alternatives to conventional plastics.

Flight simulation is a growing interest in the military to reduce accidents involving the jets used in the air force. Reducing accidents not only saves the lives of the pilots, but also money as the jets will not be destroyed. A Stewart platform can be used as a moving component to be used in flight simulation to acclimatize the pilots to moving during flight without flying a real jet. In this paper the fidelity of the roll rotational direction and the effect the roll has on the lateral sway movement will be tested. A set path will be created and then followed by the platform with a range of 12 different frequencies. These trials are then plotted against the generated data to display the correlation between them. The fidelity of the gain and phase values are calculated and plotted to show proper fidelity. The results of the study show that the platform is within the fidelity requirements to be considered a flight simulator training device.

In this study, we are reporting the fabrication of a nanocellulose (NFC) paper-based food indicator for chicken breast spoilage detection by both visual color change observation and smartphone image analysis. The indicator consists of a nanocellulose paper (nanopaper) substrate and a pH-responsive dye, bromocresol green (BCG), that adsorbs on the nanopaper. The nanopaper is prepared through vacuum filtration and high-pressure compression. The nanopaper exhibits good optical transparency and strong mechanical strength. The color change from yellow to blue in the nanopaper indicator corresponding to an increase in the solution pH and chicken breast meat storage data were observed and analyzed, respectively. Further, we were able to use color differences determined by the RGB values from smartphone images to analyze the results, which indicates a simple, sensitive, and readily deployable approach toward the development of future smartphone-based food spoilage tests.

The paper presents a proposed design for an Active-assist Rehabilitation Device for Elbow (ARDEL) to increase elbow joint mobility in patients suffering from medical conditions such as stroke, lateral epicondylitis, and medial epicondylitis. The article highlights the importance of early rehabilitation intervention for stroke survivors to prevent permanent disabilities and deformities. The effectiveness of various elbow rehabilitation devices, including dynamic elbow braces, customized elbow braces, and robotic exoskeletons, has been discussed based on previous studies. The proposed ARDEL design is aimed at addressing the supervision requirement in active-assist exercises, which is widely used by therapists for elbow rehabilitation. The design uses a 3-D printed brace, which allows the patients to perform active-assist exercises with the assistance of the device. The article emphasizes the cost-effectiveness of the proposed design and its potential for widespread accessibility. The proposed design has the potential to improve the quality of life of patients suffering from elbow joint-related medical conditions.

BACKGROUND:Hospital nurses and caregivers are reported to have the highest number of workplace injuries every year, which directly leads to missed days of work, a large amount of compensation costs, and staff shortage issues in the healthcare industry. Hence, this research study provides a new technique to evaluate the risk of injuries for healthcare workers using a combination of unobtrusive wearable devices and digital human technology. The seamless integration of JACK Siemens software and the Xsens motion tracking system was used to determine awkward postures adopted for patient transfer tasks. This technique allows for continuous monitoring of the healthcare worker's movement which can be obtained in the field.METHODS:Thirty-three participants underwent two common tasks: moving a patient manikin from a lying position to a sitting position in bed and transferring the manikin from a bed to a wheelchair. By identifying, in these daily repetitive patient-transfer tasks, potential inappropriate postures that can be conducive to excessive load on the lumbar spine, a real-time monitoring process can be devised to adjust them, accounting for the effect of fatigue. Experimental Result: From the results, we identified a significant difference in spinal forces exerted on the lower back between genders at different operational heights. Additionally, we revealed the main anthropometric variables (e.g., trunk and hip motions) that are having a large impact on potential lower back injury.CONCLUSIONS:These results will lead to implementation of training techniques and improvements in working environment design to effectively reduce the number of healthcare workers experiencing lower back pain, which can be conducive to fewer workers leaving the healthcare industry, better patient satisfaction and reduction of healthcare costs.

Poly-lactic acid (PLA) is a synthetic polymer that has gained popularity as a scaffold due to well-established manufacturing processes, predictable biomaterial properties, and sustained therapeutic release rates. However, it has some drawbacks such as weak mechanical parameters and reduced medicinal delivery efficacy after PLA degradation. The development of synthetic polymers that can release antibiotics and other medicines remains a top research priority. This study proposes a novel approach to produce PLA by converting Brewer’s spent grain (BSG) into lactic acid by bacterial fermentation followed by lactide ring polymerization with a metal catalyst. The elution properties of the PLA polymer are evaluated using modified Kirby-Bauer assays involving the antimicrobial chemotherapeutical, trimethoprim (TMP). Molded PLA polymer disks are impregnated with a known killing concentration of TMP, and the PLA is evaluated as a drug vehicle against TMP-sensitive Escherichia coli. This approach provides a practical means of assessing the polymer’s ability to release antimicrobials, which could be beneficial in exploring new drug-eluting synthetic polymer strategies. Overall, this study highlights the potential of using BSG waste materials to produce valuable biomaterials of medical value with the promise of expanded versatility of synthetic PLA polymers in the field of drug-impregnated tissue grafts.

Brewer's spent grain (BSG) is the largest waste generated from the brewing industry, accounting for similar to 39 million tons yearly. Currently, the material has limited use for feeding farm animals and presents minimal market value. There has been a growing interest in the potential recycling of BSG as a manufacturing material. In this study, we are reporting the preparation of a fully bio-based 3D printable biocomposite based on recycled BSG material. The biocomposite is composed of BSG fine particles that are blended with nanofibrillated cellulose (NFC) hydrogel. Cross-linking agent glutaraldehyde was used to improve the viscosity of the biocomposite. Our results showed the composite is a paste-like material and adaptable for 3D printing. Scanning electron microscopy (SEM) and mechanical testing were used to evaluate the surface morphology and mechanical resistance of biocomposite, respectively. A prototype for food spoilage monitoring based on the BSG-NFC biocomposite was demonstrated. It is expected that this fully bio-based composite will be a low-cost, recyclable, and sustainable 3D bio-printing material for biological applications.

Sustainable and eco-friendly biomaterials based on natural sources have increased dramatically, due to their recyclability, biodegradability, and biocompatibility.Cellulose is one of the most abundant natural biopolymers that can be produced from plants and microorganisms [1].Nanofibrillated cellulose (nanocellulose, NFC), the extracted form of the native cellulose, is composed of nanoscaled fibrils with a few micrometers in length and less than 100 nm in diameter [2].Owing to its biodegradability, biocompatibility, unique chemical binding capacity, and superior mechanical properties, NFC has attracted significant interest as an excellent alternative to petroleum-based polymer material for biomedical applications.In the current studies, we report the preparation of a biocompatible NFC-based surgery thread for dermal wound drug delivery application and the development of a low-cost and fully recyclable biocomposite for 3-D bioprinting manufacture, respectively.We prepared NFC surgery thread (nanothread) by extruding TEMPO-NFC (treated by 2,2,6,6-tetramethylpiperidine-1oxyl radical) hydrogel in an ethanol bath, followed by an air-drying process.Scanning electron microscopy (SEM) image showed that the as-fabricated nanothread has a mean diameter of ~120 µm and consists of well-aligned nanofibrils.The tensile strength test demonstrates the superior mechanical performance of the nanothread with a strength of 331 MPa and Young's modulus of 13.52 GPa, respectively.Due to its good water absorption capability, nanothread can absorb the physiological fluid and re-swell slowly.The capability to re-swelling provides an opportunity to release pre-loaded medicines in the nanothread, which can promote wound healing and prevent bacterial infection.We further incorporated fluorescent dye rhodamine 6G (R6G) to monitor the releasing profile.Our preliminary results showed that a non-linear releasing profile and the release of R6G can last for one week.The nanothread was loaded with gentamicin that showed very good antibacterial properties.Our previous studies showed that NFC based devices have good biocompatibility [3].We anticipate that the cell culture study will prove that the NFC thread can sustain cell growth as well and that the drug-loaded nanothread can be an effective strategy to promote skin wound healing.The abundant carboxylic groups and hydroxyl groups of the TEMPO-NFC nanofibril offer unique binding capacity with polysaccharides, proteins, surfactants, and plasticizers, which make the TEMPO-NFC an ideal adhesive material for 3-D bioprinting application [4].We are able to produce a novel low-cost, biodegradable and recyclable 3-D printing biocomposite that consists of NFC and brewer's spent grain (BSG).BSG is the major by-product waste from the brewing industry, consisting of 30% of non-cellulose polysaccharides [5].In a typical process, we blended NFC hydrogel with fine-grinded BSG particles.Our preliminary results show that the biocomposite is a sticky gel-like material and can further be stabilized by using glutaraldehyde, the rheology of which can be affected by BSG particle size and NFC ratio.A thermal stability test and tensile test will be conducted to evaluate the rheology and mechanical resistance.3-D printing of prototypes were demonstrated, including as an intelligent packaging indicator.We anticipate the biocomposite will be a low-cost, recyclable, and sustainable material that can be used for 3-D bioprinting manufacture.

A large percentage of musculoskeletal disorder cases occur in brewing companies. The aim of this research study is to evaluate the risk of injuries for workers in the local brewing industry by integrating the actual human motion, which was captured by the Xsens MVN Awinda motion tracking system, with the JACK Siemens ergonomics tools. This proposed fusion technology greatly overcomes the time-consuming issue in the traditionally full-body simulation and the posture sensitivity issue in the current digital human modelling (DHM) technology. In this study, the subjects performed a series of daily lifting tasks utilizing 72 kg kegs. The forces exerted on the lower back of brewery workers were fully analyzed. The maximum load applied on the hands for each of the tasks was also estimated to prevent workers from injuries. Additionally, the key factors that highly correlate to lower back injuries were emphasized. Due to the heavy load applied by the kegs, large spinal forces were exerted on the lower back of workers. Moreover, reducing trunk and hip flexion is also important to prevent workers from injuries. The results of this study can greatly improve the implementation of training techniques, environmental modifications, and assistive device design, which aim to eliminate injury risk and increase the productivity of workers within the breweries.

Flight simulators are training devices that are meant to assist the pilot in learning the mechanics and feel of flying an aircraft without actually leaving the ground. The Stewart platform is a six degree of freedom platform capable of simulation precise movements as well as vibrations. In this paper the fidelity of a Stewart platform will be tested in the surge direction as well as yaw rotation. The fidelity of the platform will be tested to ensure accuracy when being used as a flight simulator to train future pilots before they leave the ground in an aircraft to further prevent potential accidents. The movements for verification will be generated using MATLAB and used as an input to the platform which will collect the movements with a 6 axis inertial movement unit. The results show that the fidelity of the Stewart platform satisfies the standards to be used as a flight simulator training device.

COPYRIGHT © 2023 Piovesan and González. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Astronauts and spacecraft have had frequent run-ins with micrometeorites and other orbital debris. Moreover, hypervelocity impacts by micrometeoroids and orbital debris are significant hazards for spacecraft and satellites. Thermal protection and hypervelocity impact protection can be combined in a multi-layer insulation blanket. Materials like Kevlar, Twaron, and other aramid materials are used as fabric layers in the space shields. Other potential materials are Ultra High Molecular Weight Polyethylene (UHMWPE) or Dyneema and ceramic-based structures can be used as well. These materials, when used in layers can provide a good amount of protection from micrometeorites and space/orbital debris. This review paper focuses on impact testing and material characteristics done in previous studies regarding materials like Kevlar, Dyneema, and Ceramic materials. MMOD shielding capability is influenced by both, configuration, and material selection. Composites and materials with a high strength-to-weight ratio are used in the shields. Several layers like disrupt layer, standoff layer, and stopper layer are used to shield the spacecraft depending on the properties of the material used. The risk and probability of penetration due to hypervelocity impacts remain a big threat to space missions. The review also discusses experiments done on current systems related to MMOD shielding.