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1.
Cytokine ; 172: 156413, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37918054

RESUMEN

Given the clinical success of cytokine blockade in managing diverse inflammatory human conditions, this approach could be exploited for numerous refractory or uncontrolled inflammatory conditions by identifying novel targets for functional blockade. Interleukin (IL)-18, a pro-inflammatory cytokine, is relatively underestimated as a therapeutic target, despite accumulated evidence indicating the unique roles of IL-18 in acute and chronic inflammatory conditions, such as macrophage activation syndrome. Herein, we designed a new form of IL-18 blockade, i.e., APB-R3, a long-acting recombinant human IL-18BP linked to human albumin-binding Fab fragment, SL335, for extending half-life. We then explored the pharmacokinetics and pharmacodynamics of APB-R3. In addition to an extended serum half-life, APB-R3 alleviates liver inflammation and splenomegaly in a model of the macrophage activation syndrome induced in IL-18BP knockout mice. Moreover, APB-R3 substantially controlled skin inflammation in a model of atopic dermatitis. Thus, we report APB-R3 as a new potent IL-18 blocking agent that could be applied to treat IL-18-mediated inflammatory diseases.


Asunto(s)
Dermatitis Atópica , Síndrome de Activación Macrofágica , Ratones , Animales , Humanos , Dermatitis Atópica/tratamiento farmacológico , Interleucina-18/uso terapéutico , Albúmina Sérica Humana/uso terapéutico , Síndrome de Activación Macrofágica/tratamiento farmacológico , Citocinas/uso terapéutico , Factores Inmunológicos/uso terapéutico , Inflamación
2.
Medicina (Kaunas) ; 56(4)2020 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-32326179

RESUMEN

Background and objectives: Obese people have many foot-related disorders and plantar fasciitis (PF) is the most common disorder among them. However, research on the role of therapeutic exercises in PF is lacking and there is no evidence to suggest its benefits. As such, a further insight into therapeutic exercises is needed within this group. This case study investigated the effect of three-dimensional (3D) ankle exercises using a combined isotonic (CI) technique on function and balance in an obese subject with PF. Material and methods: The subject in this study was a 28-year-old obese woman who was diagnosed with PF by an orthopedic surgeon. A 3D ankle exercise program was commenced three times a week for 15 min over 4 weeks. The evaluations were conducted at five intervals: pre-test, and at 1, 2, 3 and 4 weeks from the initiation of the intervention. The tests were conducted in the following order: the patient-specific functional scale test (PSFS), an ultrasound of the plantar fascia, the heel pressure and balance test, the pressure pain threshold (PPT), and the 4-way ankle strength test. Results: The mean score of the PSFS test reduced by 70.55% after 4 weeks of the intervention. The thickness of the plantar fascia and heel pressure measured during single-leg standing decreased by 6.67% and 10.37%, respectively, after 4 weeks of the intervention. The anteroposterior and medial-lateral balance ability showed improvements of 8.29% and 8.61%, respectively, after 4 weeks of the intervention. The PPT improved by 38.01% after 4 weeks of the intervention. In the 4-way ankle strength test, dorsiflexion, plantar flexion, inversion, and eversion increased by 14.46%, 9.63%, 4.3% and 13.25%, respectively, after 4 weeks of the intervention. Conclusion: 3D ankle exercises utilizing the CI technique were shown to be effective in improving foot function, pressure pain, and muscle strength in dorsiflexion and inversion in an obese patient with PF.


Asunto(s)
Terapia por Ejercicio/métodos , Fascitis Plantar/terapia , Obesidad/complicaciones , Adulto , Tobillo/fisiopatología , Fascitis Plantar/complicaciones , Femenino , Humanos , Contracción Isotónica/fisiología , Rango del Movimiento Articular
3.
Eur Neurol ; 79(3-4): 214-220, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29614498

RESUMEN

BACKGROUND: Stroke is the second leading cause of death worldwide and remains an important health burden both for the individuals and for the national healthcare systems. Potentially modifiable risk factors for stroke include hypertension, cardiac disease, diabetes, and dysregulation of glucose metabolism, atrial fibrillation, and lifestyle factors. OBJECTS: We aimed to derive a model equation for developing a stroke pre-diagnosis algorithm with the potentially modifiable risk factors. METHODS: We used logistic regression for model derivation, together with data from the database of the Korea National Health Insurance Service (NHIS). We reviewed the NHIS records of 500,000 enrollees. For the regression analysis, data regarding 367 stroke patients were selected. The control group consisted of 500 patients followed up for 2 consecutive years and with no history of stroke. RESULTS: We developed a logistic regression model based on information regarding several well-known modifiable risk factors. The developed model could correctly discriminate between normal subjects and stroke patients in 65% of cases. CONCLUSION: The model developed in the present study can be applied in the clinical setting to estimate the probability of stroke in a year and thus improve the stroke prevention strategies in high-risk patients. The approach used to develop the stroke prevention algorithm can be applied for developing similar models for the pre-diagnosis of other diseases.


Asunto(s)
Algoritmos , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/prevención & control , Anciano , Bases de Datos Factuales , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Programas Nacionales de Salud , Análisis de Regresión , República de Corea , Factores de Riesgo , Accidente Cerebrovascular/etiología
4.
Ergonomics ; 59(7): 890-900, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26472250

RESUMEN

The objective of this study was to identify three-dimensional finger joint angles for various hand postures and object properties. Finger joint angles were measured using a VICON system for 10 participants while they pinched objects with two, three, four and five fingers and grasped them with five fingers. The objects were cylinders and square pillars with diameters of 2, 4, 6 and 8 cm and weights of 400, 800, 1400 and 1800 g. Hand posture and object size more significantly affected the joint flexion angles than did object shape and weight. Object shape affected only the metacarpophalangeal (MCP) joint angle of the index finger and the flexion angle of the MCP joint of the little finger. Larger flexion angles resulted when the hand posture was grasping with five fingers. The joint angle increased linearly as the object size decreased. This report provides fundamental information about the specific joint angles of the thumb and fingers. Practitioner Summary: Three-dimensional finger joint angles are of special interest in ergonomics because of their importance in handheld devices and musculoskeletal hand disorders. In this study, the finger joint angles corresponding to various hand postures and objects with different properties were determined.


Asunto(s)
Articulaciones de los Dedos/fisiología , Articulación Metacarpofalángica/fisiología , Postura , Adolescente , Adulto , Fenómenos Biomecánicos , Diseño de Equipo , Ergonomía , Humanos , Imagenología Tridimensional , Masculino , Adulto Joven
5.
Int J Occup Saf Ergon ; 21(1): 30-8, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26327260

RESUMEN

The purpose of this study was to compare and quantify the angle difference among marker attachment methods for kinematic evaluation. For static evaluation, a hand mock-up was designed and used in single trials of different marker attachment methods. The mean absolute angle difference between the marker attachment methods and hand mock-up was not statistically significant. For dynamic evaluation, the gripping task began when a participant gripped a cylinder. The main effect of the marker set (p < .049) was significant. Thus, the use of one marker per joint is recommended for static evaluation because it causes less discomfort when a patient moves his/her hand and because utilizing the same marker placements for each subject is easy. For dynamic evaluation, the use of three markers per segment or a cluster marker is recommended because they are less affected by skin movement.


Asunto(s)
Mano/fisiología , Movimiento/fisiología , Adulto , Fenómenos Biomecánicos , Estatura , Índice de Masa Corporal , Fuerza de la Mano , Humanos , Masculino , Salud Laboral , Rango del Movimiento Articular
6.
Int J Occup Saf Ergon ; 20(1): 91-101, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24629871

RESUMEN

This study determined flexion and extension angles of resting fingers and wrist in terms of forearm posture (neutral, pronation and supination) and shoulder flexion (0°, 45°, 90° and 135°). The participants participated in 12 angle measurements for 16 finger joints and wrist. The finger joints flexed more in supination than in neutral posture and pronation and the thumb flexed more than the other fingers because of the gravity and skin tension. This phenomenon became more apparent as the shoulder flexed. The carpometacarpal joint had the largest flexion angle in the thumb joints, whereas the proximal interphalangeal joints had the largest flexion angles in the other finger joints. The resting posture of the wrist extended of ~16° in any forearm postures when the shoulder was at 0°. The results of this study could be useful for rehabilitation tool and product designs.


Asunto(s)
Articulaciones de los Dedos/fisiología , Rango del Movimiento Articular/fisiología , Muñeca/fisiología , Adulto , Fenómenos Biomecánicos , Femenino , Humanos , Masculino , Movimiento , Postura
7.
Int J Occup Saf Ergon ; 30(1): 20-32, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36508293

RESUMEN

We evaluated the research trends in ergonomics, industrial safety and health from the 1980s to the present. In the ergonomics area, keywords and abstracts from five journals were analyzed. For industrial safety and health, six journal databases were evaluated. A frequency analysis, a semantic network of keywords and a topic network of abstracts were conducted. The results of ergonomics showed that 'macro-ergonomics' and 'manual material handling' were the most popular topics, and 'ergonomic' and 'electromyography' were the most cited keywords. 'Posture' and 'biomechanics' were the most frequently used with high centrality. The results of industrial safety and health showed that 'job stress' and 'organizational safety' were the most popular topics, and 'occupational exposure' and 'occupational health' were the most cited keywords. 'Dust' and 'exposure' were frequently used with high centrality. The results would be helpful in understanding the trends of research efforts and foreseeing trends of future research.


Asunto(s)
Exposición Profesional , Salud Laboral , Estrés Laboral , Humanos , Web Semántica , Ergonomía/métodos
8.
Int J Occup Saf Ergon ; 30(1): 1-8, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36494891

RESUMEN

Among all industrial accident-induced diseases, musculoskeletal disorders (MSDs) are most prominently observed among nurses. The physical load of everyday tasks involved in nursing work was assessed in this study using a developed risk index, whereby the physical burden was evaluated using the exposure duration and work intensity levels. This survey targeted nine small, medium and large-sized hospitals in South Korea and categorized representative nursing tasks into six groups. The subtasks within these six categories (evaluated as high risk) included changing a patient's posture and assisting with walkers or wheelchairs, transporting/handling drug carts, bathing patients, replacing bedding, traction therapy, cardiopulmonary resuscitation and artificial manual breathing unit, and computer work. The risk index ratio was significantly different by task type for each task. We demonstrated that the risk index developed in this study can be used to evaluate MSDs in hospitals.


Asunto(s)
Enfermedades Musculoesqueléticas , Enfermedades Profesionales , Humanos , Enfermedades Musculoesqueléticas/epidemiología , Ergonomía , Encuestas y Cuestionarios , Accidentes de Trabajo , República de Corea/epidemiología , Enfermedades Profesionales/epidemiología , Factores de Riesgo
9.
Front Endocrinol (Lausanne) ; 14: 1132172, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36909328

RESUMEN

Introduction: Administration of follicle-stimulating hormone (FSH) has been recommended to stimulate spermatogenesis in infertile men with hypogonadotropic hypogonadism, whose sperm counts do not respond to human chorionic gonadotropin alone. However, FSH has a short serum half-life requiring frequent administration to maintain its therapeutic efficacy. To improve its pharmacokinetic properties, we developed a unique albumin-binder technology, termed "anti-serum albumin Fab-associated" (SAFA) technology. We tested the feasibility of applying SAFA technology to create long-acting FSH as a therapeutic candidate for patients with hypogonadotropic hypogonadism. Methods: SAFA-FSH was produced using a Chinese hamster ovary expression system. To confirm the biological function, the production of cyclic AMP and phosphorylation of ERK and CREB were measured in TM4-FSHR cells. The effect of gonadotropin-releasing hormone agonists on spermatogenesis in a hypogonadal rat model was investigated. Results: In in vitro experiments, SAFA-FSH treatment increased the production of cyclic AMP and increased the phosphorylation of ERK and CREB in a dose-dependent manner. In animal experiments, sperm production was not restored by human chorionic gonadotropin treatment alone, but was restored after additional recombinant FSH treatment thrice per week or once every 5 days. Sperm production was restored even after additional SAFA-FSH treatment at intervals of once every 5 or 10 days. Discussion: Long-acting FSH with bioactivity was successfully created using SAFA technology. These data support further development of SAFA-FSH in a clinical setting, potentially representing an important advancement in the treatment of patients with hypogonadotropic hypogonadism.


Asunto(s)
Hormona Folículo Estimulante , Hipogonadismo , Cricetinae , Humanos , Masculino , Ratas , Animales , Albúmina Sérica , Células CHO , Cricetulus , Semen , Hipogonadismo/tratamiento farmacológico , Gonadotropina Coriónica/uso terapéutico , Espermatogénesis , Hormona Folículo Estimulante Humana/uso terapéutico , Proteínas Recombinantes/uso terapéutico
10.
Ergonomics ; 55(8): 885-97, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22676050

RESUMEN

This study used the observation-based method showing images on computer to evaluate angle estimation errors of 8 body segments in 3 motion planes at up to 28 segment angles and 5 camera locations with respect to goniometric measurements. Thirty observers participated in evaluating segment angles. Forearm (9.9°) and thigh (9.5°) had smaller errors than hand (14.0°) and foot had the smallest error (8.7°) due to its narrow range of motion (ROM). Errors were small with camera locations perpendicular to motions in the planes, such as 90° camera location for the flexion and extension of arm (6.3°), forearm (7.9°), thigh (6.5°), and leg (8.1°) in the sagittal plane. Segments had small errors of 3.1°, 4.6°, and 3.8° at segment angles of -90°, 0° and 90°, respectively. Care should be taken when estimating angles by the observation-based method for a specific segment motion and viewing direction is suggested to be perpendicular to the motion plane. PRACTITIONER SUMMARY: Some companies may not allow many cameras or have obstacles for working posture evaluation in the workplace. These study results can be a guideline on proper selection of the number of cameras and their locations for a specific segment and its motion of interest to reduce visual segment angle estimation errors.


Asunto(s)
Movimiento/fisiología , Observación/métodos , Fotograbar/métodos , Postura , Rango del Movimiento Articular/fisiología , Precisión de la Medición Dimensional , Humanos , Modelos Lineales , Postura/fisiología , Adulto Joven
11.
Artículo en Inglés | MEDLINE | ID: mdl-35457574

RESUMEN

Compromised physical ability due to musculoskeletal impairment among spinal cord injury (SCI) patients is known to negatively affect their quality of life. It is essential to comprehensively understand the muscle strength of the upper extremity among patients with SCI to enhance muscle function and capacity to engage in an active lifestyle. The objective of this study was to evaluate the muscle strength of 15 upper extremity muscles among patients with SCI and compare the relative weakness of individual muscles to the control group. Seven male patients with SCI with ASIA impairment scale D and E and 33 males in the control group participated in this study. Each participant performed maximal voluntary contraction of individual muscles, and the electromyography data were recorded. The results showed that the majority of the upper extremity muscles (12 out of 15) showed considerable weakness (24 to 53%) relative to the control group. Furthermore, the relative strength (ranking) of individual muscles among 15 upper extremity muscles was different between patients with SCI and the control group. This information would be useful to the selective strengthening of specific muscles as an intensive rehabilitation effort and prevent overuse and adverse injuries due to excessive muscle training.


Asunto(s)
Calidad de Vida , Traumatismos de la Médula Espinal , Electromiografía/métodos , Femenino , Humanos , Masculino , Músculo Esquelético , Músculos , Extremidad Superior
12.
Ergonomics ; 54(11): 1072-80, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22026950

RESUMEN

The objective of this study was to evaluate individual finger force and contribution to a gripping force, the difference between actual and expected finger forces and subjective discomfort rating at 10 different submaximal voluntary contraction (%MVC) levels (10-100% in 10 increments). Seventy-two participants randomly exerted gripping force with a multi-finger force measurement system. The individual finger force, gripping force and discomfort increased as %MVC levels increased. The middle and ring fingers exerted more force and contributed to a gripping force more than the index and little fingers due to their larger mass fractions of the digit flexor muscles. It was apparent at <50% MVC; however, the index finger increased its contribution and exerted even more force than expected at more than 50% MVC. Subjective discomfort supported the results of the objective measures. This could explain the conflicting findings between index and ring fingers in previous finger contribution studies. STATEMENT OF RELEVANCE: Hand tool design is of special interest in ergonomics due to its association with musculoskeletal disorders in the hand. This study reveals a different contribution pattern of the fingers in submaximal voluntary contraction of gripping exertion.


Asunto(s)
Dedos/fisiología , Fuerza de la Mano/fisiología , Contracción Muscular/fisiología , Adulto , Ergonomía , Humanos , Masculino , Fuerza Muscular/fisiología , Adulto Joven
13.
J Occup Health ; 63(1): e12292, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34766414

RESUMEN

OBJECTIVE: The objective of this study was to predict postural discomfort based on the deep learning-based regression (multilayer perceptron [MLP] model). METHODS: A total of 95 participants performed 45 different static postures as a combination of 3 neck angles, 5 trunk angles, and 3 knee angles and rated the whole-body discomfort. Two different combinations of variables including model 1 (all variables: gender, height, weight, exercise, body segment angles) and model 2 (gender, body segment angles) were tested. The MLP regression and a conventional regression (quadratic regression) were both conducted, and the performance was compared. RESULTS: In the overall regression analysis, the quadratic regression showed better performance than the MLP regression. For the postural discomfort group-specific analysis, MLP regression showed greater performance than the quadratic regression especially in the high postural discomfort group. The MLP regression also showed better performance in predicting postural discomfort among individuals who had a variability of subjective rating among different postures compared to the quadratic regression. The deep learning for postural discomfort prediction would be useful for the efficient job risk assessment for various industries that involve prolonged static postures. CONCLUSIONS: The deep learning for postural discomfort prediction would be useful for the efficient job risk assessment for various industries that involve prolonged static postures. This information would be meaningful as basic research data to study in predicting psychophysical data in ergonomics.


Asunto(s)
Aprendizaje Profundo , Ergonomía , Dolor/diagnóstico , Postura , Adulto , Femenino , Humanos , Masculino , Valor Predictivo de las Pruebas , Análisis de Regresión , Medición de Riesgo/métodos
14.
PLoS One ; 16(2): e0246870, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33571318

RESUMEN

The objective of this study was to accurately predict the grip strength using a deep learning-based method (e.g., multi-layer perceptron [MLP] regression). The maximal grip strength with varying postures (upper arm, forearm, and lower body) of 164 young adults (100 males and 64 females) were collected. The data set was divided into a training set (90% of data) and a test set (10% of data). Different combinations of variables including demographic and anthropometric information of individual participants and postures was tested and compared to find the most predictive model. The MLP regression and 3 different polynomial regressions (linear, quadratic, and cubic) were conducted and the performance of regression was compared. The results showed that including all variables showed better performance than other combinations of variables. In general, MLP regression showed higher performance than polynomial regressions. Especially, MLP regression considering all variables achieved the highest performance of grip strength prediction (RMSE = 69.01N, R = 0.88, ICC = 0.92). This deep learning-based regression (MLP) would be useful to predict on-site- and individual-specific grip strength in the workspace to reduce the risk of musculoskeletal disorders in the upper extremity.


Asunto(s)
Aprendizaje Profundo , Fuerza de la Mano/fisiología , Redes Neurales de la Computación , Algoritmos , Femenino , Humanos , Masculino , Adulto Joven
15.
Healthcare (Basel) ; 9(6)2021 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-34205155

RESUMEN

Obese people are prone to foot deformities such as flat feet. Foot management programs are important to prevent them. This study investigated the effects of two foot-ankle interventions on balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions in obese people with pes planus for four weeks. The experiment was designed as a randomized controlled trial. Twenty-four participants who met the inclusion criteria were selected, and they were randomly assigned to either a short foot group (SFG) or proprioceptive neuromuscular facilitation group (PNFG) according to foot-ankle intervention. Two interventions were commenced three times a week for 20 min over four weeks. The tests were conducted at two intervals: pre-intervention and at four weeks. The tests were conducted in the following order: the patient-specific functional scale test (PSFS), an ultrasound of the plantar fascia, the navicular drop test, balance test, and the four-way ankle strength test. Two groups showed significant differences in balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions between pre-test and post-test (p < 0.05). PNFG had significantly higher dorsiflexor and invertor strength than SFG (p < 0.05). SF and PNF interventions were effective to improve balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions in obese people with pes planus. Additionally, PNF intervention is more beneficial in increasing the dorsiflexor and invertor strength compared to SF intervention.

16.
Electrophoresis ; 31(18): 3053-60, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20725917

RESUMEN

The development of a simple, sensitive, and direct method for the total analysis of certain endocrine disruptors was performed by integrating preconcentration steps to a separation step on a microchip through the modification of the field-amplified sample stacking and field-amplified sample injection steps. To improve the preconcentration and separation performances, the preconcentration and separation buffers were modified with citrate-stabilized gold nanoparticles (AuNPs). For the detection of the separated samples, cellulose-dsDNA/AuNPs-modified carbon paste electrodes were used at the channel end. The experimental parameters affecting the analytical performances, such as the buffer concentration, water plug length, SDS concentration in the separation buffer, AuNPs concentration, preconcentration time, detection potential and electrode to channel distance, were examined. The detection limits of the test compounds were between 7.1 and 11.1 fM and that for 4-pentylphenol was 7.1 (±1.1) fM. Dynamic ranges were in the range from 0.15 to 600.0 pM. The experiments with real samples were performed to evaluate the reliability of the proposed method.


Asunto(s)
Electroforesis por Microchip/métodos , Disruptores Endocrinos/análisis , Oro/química , Nanopartículas del Metal/química , Fenoles/análisis , Carbono/química , Celulosa/química , ADN/química , Electrodos , Modelos Lineales , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Temperatura , Agua/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación
17.
Artículo en Inglés | MEDLINE | ID: mdl-33182760

RESUMEN

The objectives of this study were to evaluate the effect of gender and postures of the neck, trunk, and knee on overall postural discomfort, and to classify combined postures into different postural discomfort groups. A total of 95 participants (42 males and 53 females) performed 45 different static postures, which were a combination of 3 neck angles, 5 trunk angles, and 3 knee angles, and rated the perceived postural discomfort. Non-hierarchical K-means cluster analysis was employed to classify the 45 different combined postures into several postural discomfort groups. Postural discomfort was significantly affected by gender and postures of the neck, trunk, and knee (p < 0.001). Three clusters (high, medium, and low discomfort) were identified and the postural discomfort was significantly different between clusters (p < 0.001). The high discomfort group consisted of mostly males with high knee and trunk flexion angles and a moderate neck flexion angle. The low discomfort group was female-dominant with low neck and trunk flexion angles and a moderate knee flexion angle. The different flexibility (stiffness) of the joint motions between genders may affect the gender difference in postural discomfort. The knee and trunk postures were critical to the postural balance, which may affect the perception of whole-body discomfort. This result will be useful for developing and improving postural observation tools.


Asunto(s)
Análisis por Conglomerados , Articulación de la Rodilla , Cuello , Dolor , Postura , Torso , Femenino , Humanos , Masculino , Dolor/clasificación , Equilibrio Postural , Rango del Movimiento Articular
18.
Work ; 65(3): 497-507, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32116269

RESUMEN

BACKGROUND: One-handed lifting commonly occurs in the industry. Specific guidelines of proper heights during one-handed lifting could be valuable information to design or to assess the risk of work environment. OBJECTIVE: The objective of this study was to determine the maximum acceptable height and comfortable height during one-handed vertical lifting by gender, participant height, hand, and object weight. METHODS: Based on the psychophysical method, 72 males and 50 females, divided into four different height groups, determined their maximum acceptable and comfortable heights by each hand (left and right) and various object weights (1 kg, 3 kg, 5 kg, and 8 kg). RESULTS: Males revealed significantly greater maximum acceptable heights (males: 157 cm; females: 135 cm) and higher comfortable heights (males: 104 cm; females: 96 cm) compared to females. The participants' heights, which hand was used to lift, and the object weight were significant factors in determining the maximum acceptable height for both males and females. The multiple linear regression model of the maximum acceptable height showed more robust predictive power (R2 = 0.55) compared to the comfortable height (R2 = 0.20) as a function of gender, participant height, hand, and object weight. CONCLUSIONS: Results suggest that gender, participant height, hand, and object weight are important variables to consider when determining the proper surface height of one-handed vertical lifting. Using the robust predictive model, an appropriate maximum acceptable height could be suggested based on the material handler's anthropometric information and object weight.


Asunto(s)
Ergonomía , Elevación , Adulto , Estatura , Femenino , Lateralidad Funcional , Mano , Humanos , Corea (Geográfico) , Masculino , Psicofísica , Factores Sexuales , Análisis y Desempeño de Tareas
19.
Saf Health Work ; 11(2): 222-227, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32596019

RESUMEN

BACKGROUND: This study investigated the effect of increased job stress, caused by musculoskeletal disease (MSD) among firefighters, on a firefighter's intention to leave the profession, henceforth referred to as "turnover intention," and verified the moderating effect of mindfulness on such a relationship. METHODS: A survey involving a total of 549 Korean male firefighters as participants was conducted herein, and the following results were obtained: the mediation effect of the MSD to turnover intention through job stress was confirmed, and the indirect effect of job stress was verified. RESULTS: We verified the moderated mediation effect of mindfulness on the relation:MSD, job stress, and turnover intention. The conditional indirect effect for middle and high levels of mindfulness is significant. CONCLUSION: The result of this study is supported by proofs of the relationship between a firefighter's MSD, job stress, and turnover intention, and these case studies reveal the moderated mediation effect of dispositional mindfulness.

20.
Int J Occup Saf Ergon ; 26(1): 91-100, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29889649

RESUMEN

Introduction. The objective of this study was to measure the effect of hand postures and object properties on nine forearm muscle activities and their contribution using surface electromyography. Methods. Ten male university students participated in the experiment. The objects used were cylindrical and rectangular, with lengths and weights of 2, 4, 6 and 8 cm and 400, 800, 1400 and 1800 g. The experimenter told the participant to pick up the object using a particular hand posture, lift the object to approximately shoulder height and maintain this posture for 3 s. Results. The hand posture, object size and object weight greatly influenced the muscle activities, but the object shape did not. Pinching with two or three fingers yielded the greatest muscle activities with the 8-cm, 1800-g object. The extensor pollicis longus and flexor pollicis longus muscles exhibited the highest submaximal voluntary contraction. Conclusion. This study provides basic information about the specific activities of the forearm muscles and the effects of the hand postures and object properties on those activities.


Asunto(s)
Electromiografía , Antebrazo/fisiología , Mano/fisiología , Adulto , Humanos , Masculino , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Postura/fisiología , Análisis y Desempeño de Tareas , Adulto Joven
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