A follow-up study of the association between mobile phone use and symptoms of ill health

Objectives: The duration and frequency of mobile phone calls, and their relationship with various health effects, have been investigated in our previous cross-sectional study. This 2-year period follow-up study aimed to assess the changes in these variables of same subjects.Methods: The study population comprised 532 non-patient adult subjects sampled from the Korean Genome Epidemiology Study. The subjects underwent a medical examination at a hospital in 2012/2013 and revisited the same hospital in 2014/2015 to have the same examination for the characteristics of mobile phone use performed. In addition, to evaluate the effects on health, the Headache Impact Test-6 (HIT-6), Psychosocial Well-being Index-Short Form, Beck Depression Inventory, Korean-Instrumental Activities of Daily Living, Perceived Stress Scale, Pittsburgh Sleep Quality Index, and 12-item Short Form Health Survey were analyzed. For all these tests, the higher the score, the greater the effect on health. Variances between scores in all the indices in the baseline and follow-up surveys were calculated, and correlations of each index were analyzed.Results: The average duration per call and HIT-6 score of the subjects decreased significantly compared with those recorded two years ago. The results showed a slight but significant correlation between call duration changes and HIT-6 score changes for female subjects, but not for males. HIT-6 scores in the follow-up survey significantly decreased compared to those in the baseline survey, but long-time call users (subjects whose call duration was ≥5 minutes in both the baseline and follow-up surveys) had no statistically significant reduction in HIT-6 scores.Conclusions: This study suggests that increased call duration is a greater risk factor for increases in headache than any other type of adverse health effect, and that this effect can be chronic.

A follow-up study of the association between mobile phone use and symptoms of ill health

Objectives: The duration and frequency of mobile phone calls, and their relationship with various health effects, have been investigated in our previous cross-sectional study. This 2-year period follow-up study aimed to assess the changes in these variables of same subjects. Methods: The study population comprised 532 non-patient adult subjects sampled from the Korean Genome Epidemiology Study. The subjects underwent a medical examination at a hospital in 2012/2013 and revisited the same hospital in 2014/2015 to have the same examination for the characteristics of mobile phone use performed. In addition, to evaluate the effects on health, the Headache Impact Test-6 (HIT-6), Psychosocial Well-being Index-Short Form, Beck Depression Inventory, Korean-Instrumental Activities of Daily Living, Perceived Stress Scale, Pittsburgh Sleep Quality Index, and 12-item Short Form Health Survey were analyzed. For all these tests, the higher the score, the greater the effect on health. Variances between scores in all the indices in the baseline and follow-up surveys were calculated, and correlations of each index were analyzed. Results: The average duration per call and HIT-6 score of the subjects decreased significantly compared with those recorded two years ago. The results showed a slight but significant correlation between call duration changes and HIT-6 score changes for female subjects, but not for males. HIT-6 scores in the follow-up survey significantly decreased compared to those in the baseline survey, but long-time call users (subjects whose call duration was ≥5 minutes in both the baseline and follow-up surveys) had no statistically significant reduction in HIT-6 scores. Conclusions: This study suggests that increased call duration is a greater risk factor for increases in headache than any other type of adverse health effect, and that this effect can be chronic.

Development and prospect of dynamic dummy research / 医用生物力学

The dynamic dummy plays an important role in the research of protecting human beings from impact environment. To collect data from dummy in dangerous impact tests is the fundamental method used in developing protection equipment and systems in aerospace, automobile and other industries. The performances of a dummy depend on its simulation degree, as well as the quality and quantity of sampled signals. The dummy technology abroad is now indispensable in developing the protection of aviation ejection and rescue system, and also beneficial to automobile and other industries. China had no Chinese characterized dummy applied until the year of 2003 when the dynamic dummy was created in Institute of Aviation Medicine, and the dummy has equivalent high performance as that made by the United States and has been availably exerted in aviation. For evaluating the impact injuries on Chinese human beings, it is necessary to further develop Chinese characterized dummy series, and to establish the all-around criteria by strengthening application of digital virtual dummy in impact environment study.

Características mecánicas dinámicas de la tibia aislada de perro sometida a prueba de impacto / Dynamic mechanical characteristics of the isolated dog tibia, subjected to impact test

El propósito del presente trabajo es brindar información acerca de las propiedades biomecánicas y morfológicas de la tibia de perro sometida a cargas dinámicas. Los objetivos fueron evaluar la resistencia de la tibia frente al impacto mediante el Método de Ensayo Charpy, relacionar la misma con el área total, el área cortical y el área de la cavidad medular del hueso, comparándola entre talla, edad y sexo diferente. La importancia clínica, ortopédica y quirúrgica que reviste la región de la pierna del perro fundamenta esta investigación. Se utilizaron tibias de perro en condiciones aisladas, extraídas postmortem de 30 animales mestizos adultos jóvenes provenientes del servicio de zoonosis de la ciudad de Río Cuarto. Se determinó en la tibia derecha e izquierda: peso y longitud total del hueso, diámetros cráneo-caudal y latero-medial en la mitad de la diáfisis. A la tibia izquierda se le practicó osteotomía transversal en la mitad de su diáfisis. En la superficie de sección se midió: espesor de la cortical, diámetro medular y se obtuvo el área de sección total, área cortical y área medular. La tibia derecha fue sometida al Método de Ensayo Charpy. Se realizó el análisis estadístico correspondiente. La resistencia del hueso presentó una correlación de r=0,70 (p= 0,000019); r=0,67 (p=0,000059) y r=0,29 (p=0,12) con respecto a las áreas cortical, total y medular respectivamente. La morfología tiene influencia sobre las propiedades biomecánicas del hueso. A medida que aumenta el área cortical aumenta la energía de impacto absorbida. En cambio, a mayor área de cavidad medular la energía de impacto absorbida aumenta pero en menor magnitud. Existen diferencias estadísticamente significativas (p=0,0168) entre la talla del animal y la resistencia de la tibia. La edad (p=0,73) y el sexo (p=0,18) no presentaron influencias significativas sobre las propiedades biomecánicas de la tibia.

The purpose of this work is to provide information about biomechanical and morphological properties of the dog tibia bone subject to dynamic loads. The objectives were: evaluate the resistance of the tibia subject impact used Charpy test Method; linking it with total area, cortical area and bone marrow cavity; and compare it with weight, age and sex categories. The clinical, orthopedical and surgical relevance of the dog leg region is the basis for this research. Dog tibia were used in isolated conditions, removed postmortem from 30 adult animals defined raceless, from the zoonoses service of the city of Río Cuarto. Weight and total bone length, cranial-caudal and lateral-medial diameter in the middle of the diaphysis, were determined in the left and right tibia. The left tibia was osteotomized transversely in the middle of the diaphysis. On the surface section we measured: cortical thickness, diameter of the bone marrow cavity, and obtained the total section area, cortical area and medullary area. The right tibia was subjected to Charpy test method. Statistical analysis was performed accordingly. The bone strength showed a correlation of r=0.70 (p= 0.000019); r=0.67 (p=0.000059) and r=0.29 (p=0.12) with respect to the cortical area, total area and medullary area respectively. The morphology has influence on the biomechanical properties of bone, with increasing cortical area increases the impact energy absorbed. In contrast, a greater area of the medullary cavity of impact energy absorbed increases but to a lesser magnitude. There were statistically significant differences (p=0.0168) of size on the strength of the tibia. Age (p=0.7343) and sex (p=0.1898) had no significant influence on the biomechanical properties of the tibia.

Effect of fiber reinforcement on impact strength of heat polymerized polymethyl methacrylate denture base resin: in vitro study and SEM analysis

PURPOSE: The aim of this in-vitro investigation was to describe the effect of reinforcement with different fibers on impact strength of heat polymerized polymethyl methacrylate (PMMA) denture base resin and to analyze the effect of surface treatment of the fibers on the impact strength. MATERIALS AND METHODS: The specimens were fabricated from the dies formed as per standard ASTM D4812. 2% by weight of glass, polyethylene and polypropylene fibers were incorporated in the PMMA resin. The Izod impact testing was performed on the unnotched specimens and the values obtained were analyzed using appropriate one way ANOVA, followed by unpaired t-test. Fractured ends of the samples were subjected to the SEM analysis. RESULTS: The polypropylene fibers with plasma treatment showed the highest impact strength (9.229 x 10(2) J/m) followed by the plasma treated polyethylene fibers (9.096 x 10(2) J/m), untreated polypropylene fibers (8.697 x 10(2) J/m), untreated polyethylene fibers (7.580 x 10(2) J/m), silane treated glass fibers (6.448 x 10(2) J/m) and untreated glass fibers (5.764 x 10(2) J/m). Also the surface treatment of all the fibers has shown the significant improvement in impact strength. Findings of the SEM analysis justified the improvement in impact strength after surface treatment. CONCLUSION: Reinforcement with the fiber is an effective method to increase the impact strength of PMMA denture base resin. The surface treatment of fibers further increases the impact strength significantly.

Effect of fiber reinforcement on impact strength of heat polymerized polymethyl methacrylate denture base resin: in vitro study and SEM analysis

PURPOSE: The aim of this in-vitro investigation was to describe the effect of reinforcement with different fibers on impact strength of heat polymerized polymethyl methacrylate (PMMA) denture base resin and to analyze the effect of surface treatment of the fibers on the impact strength. MATERIALS AND METHODS: The specimens were fabricated from the dies formed as per standard ASTM D4812. 2% by weight of glass, polyethylene and polypropylene fibers were incorporated in the PMMA resin. The Izod impact testing was performed on the unnotched specimens and the values obtained were analyzed using appropriate one way ANOVA, followed by unpaired t-test. Fractured ends of the samples were subjected to the SEM analysis. RESULTS: The polypropylene fibers with plasma treatment showed the highest impact strength (9.229 x 10(2) J/m) followed by the plasma treated polyethylene fibers (9.096 x 10(2) J/m), untreated polypropylene fibers (8.697 x 10(2) J/m), untreated polyethylene fibers (7.580 x 10(2) J/m), silane treated glass fibers (6.448 x 10(2) J/m) and untreated glass fibers (5.764 x 10(2) J/m). Also the surface treatment of all the fibers has shown the significant improvement in impact strength. Findings of the SEM analysis justified the improvement in impact strength after surface treatment. CONCLUSION: Reinforcement with the fiber is an effective method to increase the impact strength of PMMA denture base resin. The surface treatment of fibers further increases the impact strength significantly.

Características mecánicas dinámicas del fémur aislado de perro, sometido a prueba de impacto / Dynamic mechanical characteristics of the isolated dog femur, subjected to impact test

El presente trabajo tiene el propósito de brindar información acerca del comportamiento biomecánico del fémur de perro sometido a cargas dinámicas. El objetivo es evaluar la resistencia del fémur frente al impacto, mediante el Método de Ensayo Charpy, relacionando dicha resistencia con las áreas: total, cortical y cavidad medular del hueso, comparándola entre edad y sexo diferentes. Se utilizaron fémur de perro en condiciones aisladas, extraídos postmortem de 30 animales mestizos adultos, provenientes del servicio de zoonosis de la ciudad de Río Cuarto. Se determinó en los fémures derecho e izquierdo: peso y longitud total del hueso, diámetro cráneo-caudal y latero-medial en la mitad de la diáfisis. El fémur izquierdo fue osteotomizado transversalmente en la mitad de su diáfisis. En la superficie de sección se medió espesor de la cortical y diámetro medular. Se obtuvo el área de sección total, cortical y medular. El fémur del miembro pélvico derecho fue sometido al Método de Ensayo Charpy. Los resultados obtenidos fueron analizados estadísticamente encontrándose que el área cortical depende linealmente de la longitud del hueso (r=0,62, p= 0,00025); la resistencia del hueso depende de las áreas cortical (r=0,71, p= 0,000012) y área total (global) (r=0,63, p= 0,00021) y no del área medular (r=0,29, p= 0,12). El análisis exploratorio muestra que no existirían diferencias acerca de la influencia de la edad y el sexo sobre la resistencia del fémur. Tras estos resultados se puede inferir que a medida que aumenta el área cortical aumenta la energía de impacto absorbida.

This paper is intended to provide information about biomechanical behavior femur at impact using the Charpy test method relating the resistance in the following areas: total, cortical and medullary bone cavity, comparing these between different ages and sexes. Dog femors were used in isolated conditions, removed postmortem from 30 adult animals, defined raceless, from the zoonoses service of the city of Rio Cuarto. Weight, total bone length, cranio-caudal diameter and lateral medial half of the diaphysis, were determined in the left and right femur. The left femur was osteotomized transversely in the middle of the diaphysis. In the sectional area thickness of the cortical and medullary diameters were measured. We obtained the total sectional area, cortical and medullary. The femur of the right lower limb was subjected to the Charpy test method. Results were statistically analyzed and found that cortical area depends linearly on the length of the bone (r=0.62, p=0.00025), bone strength depends on the cortical areas (r=0.71, p=0.00012) and total (global) areas (r=0.63, p=0.00021) and not of the medullary area (r=0.29, p=0.12). Exploratory analysis showed that no difference existed regarding age and sex influence on the strength of the femur. Following these results we can infer that as cortical area increases, the impact energy absorbed also increases.

Validity and Reliability Assessment of Korean Headache Impact Test-6 (HIT-6)

BACKGROUND: Quality-of-life measurement represents an important tool for evaluating the management and impact of headache on individuals and society. The Headache Impact Test-6 (HIT-6) is a simple instrument developed to assess headache-related disability in Western countries. The objective of this study was to determine the reliability and validity of the Korean HIT-6. METHODS: Participants were recruited from patients who visited the Neurology Clinic of Hallym University Sacred Heart Hospital due to headache. The survey included the SF-36 and HIT-6. Headache diagnosis was assigned using ICHD-II after completing a semistructured diagnostic interview. RESULTS: A total of 43 patients were recruited, who were aged 35.2+/-13.6 years (mean+/-SD). Thirty-three and three were diagnosed as having migraine and probable migraine, respectively. Eight and two were diagnosed with tension-type and probable tension-type headache, respectively. There was a negative correlation between the total SF-36 and HIT-6 scores (Spearman's correlation coefficient=-0.64, p<0.01). Similar significant negative correlations were also observed between SF-36 physical health summary and HIT-6 scores (Spearman's correlation coefficient=-0.54, p<0.01), and between SF-36 mental summary and HIT-6 scores (Spearman's correlation coefficient=-0.60, p<0.01). The Cronbach's alpha of HIT-6 was 0.85. CONCLUSIONS: The Korean HIT-6 is a valid and reliable instrument for assessing headache-related quality of life.

Headache Impact Test-6 (HIT-6) Scores for Migraine Patients: Their Relation to Disability as Measured from a Headache Diary

BACKGROUND AND PURPOSE: Complete information on migraine-related disabilities facilitate the making of appropriate treatment decisions. Although the accessibility and ease of use of the Headache Impact Test-6 (HIT-6) make it a very promising instrument, there are few data available for comparing HIT-6 scores with the actual amount of disability. METHODS: To determine whether the disability measured using the HIT-6 questionnaire realistically reflects the amount of disability as extracted from a headache diary, which would help when deciding a management plan, 130 patients with migraine without aura were instructed to complete a headache diary on the days on which headache occurred. Each diary booklet also contained questions on the resulting disability, and comprised five items originating from the Migraine Disability Assessment Scale. After submitting their diaries, the participants completed the HIT-6 for the same time period. RESULTS: Disability as recorded in diaries was present for a mean of 2.7 days per month, and its duration differed significantly with HIT-6 score: 0.9, 2.6, and 4.6 days per month for littleto-no impact, moderate impact, and severe impact, respectively. The summed disability score from diaries was also related to the HIT-6 score. Headache frequency was the only headache characteristic that contributed significantly to the HIT-6 score. CONCLUSIONS:This study demonstrates that the HIT-6 could be useful for assessing headache-related disability in migraine patients, especially given that the questionnaire is both simple and ease of use.

The Effect of a Chitosan Coating of Dental Implant on the shock Absorption under Impact Test

With the object of providing a temporary artificial periodonal ligament-like membrane around the dental implant, 10 Branemark type implants were coated with commercially available chitosan(Fluka Co., Buchs, Switzerland) which has a molecular weight of 70,000 and 80% deacetylation degree. Once this bioactive hydrophillic polymer(chitosan) contacts with blood or wound fluids, it becomes swollen and penetrates into the adjacent cancellous bone. Thus the interface between implant and surrounding bone is completely filled with chitosan. This tight junction in early healing phase enhances primary stability. The chitosan coated dental implants were implanted into the fresh patella bones from porcine knees, since the thickness of cortical bone is relatively even and their cancellous structure is homogenous. To test the shock absorbing effect, 1mm delta-rogette strain gage was installed behind the implant. The results showed 1. the principal strain peak value directed to the impact of coated implant was 0.064 0.018(p<0.05) and that of uncoated implant was 0.095(0.032 p<0.05). 2. the peak time delay of coated implant was 0.056sec(0.011 p<0.05) and that of uncoated implant was 0.024sec(0.009 p<0.05). It can be reasoned from this results that the chitosan coating has a shock absorbing effect comparable with a temporary artificial periodontal ligament.