Assessment of differences in mechanical properties and thickness of temporal and occipital bones and correlation with age in Japanese forensic samples.

The mechanical properties and thickness of adult temporal and occipital bones were examined in modern Japanese forensic samples. Cranial bones were obtained from 293 Japanese corpses (179 men and 114 women). During autopsy, left temporal (LT), right temporal (RT), and occipital (O) bone samples were extracted from each skull. Sample thickness (ST) was measured using multidetector computed tomographic imaging. The fracture load (FL) of each sample was measured by a bending test, in which the flexural strength (FS) was calculated. The FL and ST values for O were significantly greater compared with those of the LT and RT bones. The temporal bones were thinner compared with other parts of the skull and at greater risk for fracture. There is a need to take precautions to prevent temporal bone fractures. There were no significant differences in any of the values between LT and RT, indicating bilateral symmetry of the temporal bones. There were significant negative correlations between age and the FL and FS values for all sites in both sexes, except for O in the male samples, suggesting that older individuals are at increased risk for fractures. No significant correlations were observed between age and ST values in any of the samples. There were significantly positive correlations between FL and ST values at all sites regardless of sex.

Statistical analysis of biomechanical properties and size of the sternum and its fracture risk in a Japanese sample.

OBJECTIVE: Sternal fractures can have life-threatening complications. To understand chest injury mechanisms, sufficient data regarding the mechanical properties and structure of the sternum are required. The aim of this study was to examine the mechanical properties and size of the sternum in a Japanese forensic sample. MATERIALS AND METHODS: Sterna were obtained from 120 Japanese dead bodies of known age and sex. The sample thickness (ST) and the sample width (SW) were measured using a computed tomographic image. Three-point-bending tests were conducted using a three-point-bending apparatus to assess the fracture load (FL) of the sample. Then, the flexural strength (FS) was calculated and the natural logarithm of FL (ln FL) and FS (ln FS) were also calculated. RESULTS: The values of ST, ln FL, and ln FS for male samples were significantly greater than those for female samples. Both ln FL and ln FS had significant negative correlations with age regardless of sex; the Pearson product-moment correlation coefficients were larger for female samples than for male samples. Although age was significantly negatively correlated with SW in female samples, there was no significant correlation between age and SW in male samples. No significant correlations were found between age and ST regardless of sex. CONCLUSION: This is the first study to present quantitative data on the biomechanical properties of the sternum. Because of the smaller sternal strength of elderly women, it is especially important for them to avoid the risk of sternal fractures.

Statistical analysis of the thickness and biomechanical properties of Japanese children's skulls.

OBJECTIVE: The structure and strength of a child's skull are important in accurately determining what and how external forces were applied when examining head injuries. The aims of this study were to measure skull thickness and strength in children, evaluate sex differences, and investigate the correlation between skull thickness and strength and age. MATERIALS AND METHODS: Skulls were obtained from 42 Japanese dead bodies under 20 years of age. During the autopsies, bone samples were taken from each skull. The length, width, and central thickness of the skulls were measured using calipers. Three-point bending tests were conducted, and bending load and displacement were recorded. Bending stress and bending strain were calculated, and Young's modulus, 0.2% proof stress, and maximum stress were obtained. RESULTS: In cases under 1.5 years old, 14 out of 46 male samples and 20 out of 40 female samples did not fracture during the three-point bending test, though no significant sex differences were detected. No significant differences in age, sample thickness, Young's modulus, 0.2% proof stress, or maximum stress were detected between the sexes. The sample thickness, Young's modulus, 0.2% proof stress, and maximum stress increased significantly and logarithmically with age (R2 = 0.761-0.899). Although age correlated with thickness, Young's modulus, and maximum stress more in females than in males, 0.2% proof stress correlated slightly better in males than in females. CONCLUSION: The skulls of preschool children, in particular, are thin, have low strength, and are at high risk of fracturing even with relatively small external forces. Unlike adults, no significant sex differences in skull thickness or strength were observed in children.

Assessing Handrail-Use Behavior during Stair Ascent or Descent Using Ambient Sensing Technology.

The increasing geriatric population across the world has necessitated the early detection of frailty through the analysis of daily-life behavioral patterns. This paper presents a system for ambient, automatic, and the continuous measurement and analysis of ascent and descent motions and long-term handrail-use behaviors of participants in their homes using an RGB-D camera. The system automatically stores information regarding the environment and three-dimensional skeletal coordinates of the participant only when they appear within the camera's angle of view. Daily stair ascent and descent motions were measured in two houses: one house with two participants in their 20s and two in their 50s, and another with two participants in their 70s. The recorded behaviors were analyzed in terms of the stair ascent/descent speed, handrail grasping points, and frequency determined using the decision tree algorithm. The participants in their 70s exhibited a decreased stair ascent/descent speed compared to other participants; those in their 50s and 70s exhibited increased handrail usage area and frequency. The outcomes of the study indicate the system's ability to accurately detect a decline in physical function through the continuous measurement of daily stair ascent and descent motions.

Injury Prevention Education for Changing a School Environment Using Photovoice.

According to a report by the Japan Sport Council, more than 1 million injuries occur in the school environment in Japan, which is a significant burden to society in terms of children's physical and psychological well-being as well as the costs of health care. Japanese people are becoming increasingly aware of school safety, but no effective safety education program has yet been established. In this study, we conducted a comprehensive safety education curriculum utilizing photovoice in a needs assessment of school safety and evaluated its use as a tool in student learning processes with regard to injury. The curriculum consists of two parts: (1) classroom lectures (three classes, 45 minutes each) and (2) a photovoice project (four classes, 45 minutes each). In total, 49 students participated in the education program, presenting 23 photovoice pictures. The use of photovoice enabled identification of locations of risk recognized by students and the associated photo R-map assisted students and teachers to deepen their learning about injury. We demonstrated four benefits of applying photovoice to school-based injury prevention education. These findings suggest that our photovoice-based injury prevention education program could positively impact children's research engagement by identifying school needs, and also empower them to affect social change.

Analysis of Relationship between Natural Standing Behavior of Elderly People and a Class of Standing Aids in a Living Space.

As the world's population ages, technology-based support for the elderly is becoming increasingly important. This study analyzes the relationship between natural standing behavior measured in a living space of elderly people and the classes of standing aids, as well as the physical and cognitive abilities contributing to household fall injury prevention. In total, 24 elderly standing behaviors from chairs, sofas, and nursing beds recorded in an RGB-D elderly behavior library were analyzed. The differences in standing behavior were analyzed by focusing on intrinsic and common standing aid characteristics among various seat types, including armrests of chairs or sofas and nursing bed handrails. The standing behaviors were categorized into two types: behaviors while leaning the trunk forward without using an armrest as a standing aid and those without leaning the trunk forward by using an arrest or handrail as a standing aid. The standing behavior clusters were distributed in a two-dimensional map based on the seat type rather than the physical or cognitive abilities. Therefore, to reduce the risk of falling, it would be necessary to implement a seat type that the elderly can unconsciously and naturally use as a standing aid even with impaired physical and cognitive abilities.

Understanding Parental Perceptions of Content-Specific Barriers to Preventing Unintentional Injuries in the Home.

BACKGROUND: Preventable injuries are the leading cause of death in children around the world, including in Japan. As children under the age of 5 years spend most of their time at home, home injury prevention is critical for child safety. The purpose of this study was to identify specific, focused, and precise barriers against injury prevention practice. METHODS: We conducted an online survey to examine the barriers faced by parents when taking actions to prevent home injuries. RESULTS: The results revealed common reasons why parents do not or cannot take a recommended action across injury types, and that the magnitude of importance for a specific barrier depends on the type of injury. CONCLUSIONS: Identifying content-specific barriers could help researchers and educators understand parents' needs, discuss what barriers are more important than others by injury type, and develop effective strategies based on the 3Es of injury prevention (enforcement, engineering, and education).

Study on the Causes, Types, and Mechanisms of Childhood Injuries-Age and Disease Specificity.

INTRODUCTION: To clarify the causes, types, and mechanisms of injuries in children, we collected injury cases and analyzed their causes. METHODS: During the 3-year period from 2013, we collected injury cases from three sources: nursery schools and kindergartens (A), emergency clinics of hospitals (B), and schools and a clinic for the developmentally disabled (C), using a format designed by Safe Kids Japan. RESULTS: In all, 383 cases were collected during the 3-year period. The causes of the injuries in group A were crashes, falls, and so on. The types of injuries were cuts, bruises, fractures, injuries of teeth, etc. Dislocations and abrasions were prominent in nursery school children (aged less than 3 years) and bone fractures were prominent in kindergarten children aged more than 3 years.Group B consisted of 144 cases. The most common causes of injuries were falls, traffic accidents, and so on, and the types of injuries were fractures, abrasions, sprains, etc. The incidence of fractures was particularly high and 50% of the accidents were bicycle accidents.Group C consisted of 41 cases. Although the age distribution was similar to that of group B, the types of accidents and injuries were similar to those of group A.The Bodygraphic Injury Surveillance System (BISS) analysis showed that groups A and C were similar, that is, injuries occurred mainly to the head, whereas in group B, the extremities were mainly affected. CONCLUSIONS: We analyzed the causes, types, and mechanisms of childhood injuries. The BISS may help to clarify the mechanisms of injuries in childhood.

RotationNet for Joint Object Categorization and Unsupervised Pose Estimation from Multi-View Images.

We propose a Convolutional Neural Network (CNN)-based model "RotationNet," which takes multi-view images of an object as input and jointly estimates its pose and object category. Unlike previous approaches that use known viewpoint labels for training, our method treats the viewpoint labels as latent variables, which are learned in an unsupervised manner during the training using an unaligned object dataset. RotationNet uses only a partial set of multi-view images for inference, and this property makes it useful in practical scenarios where only partial views are available. Moreover, our pose alignment strategy enables one to obtain view-specific feature representations shared across classes, which is important to maintain high accuracy in both object categorization and pose estimation. Effectiveness of RotationNet is demonstrated by its superior performance to the state-of-the-art methods of 3D object classification on 10- and 40-class ModelNet datasets. We also show that RotationNet, even trained without known poses, achieves comparable performance to the state-of-the-art methods on an object pose estimation dataset. Furthermore, our object ranking method based on classification by RotationNet achieved the first prize in two tracks of the 3D Shape Retrieval Contest (SHREC) 2017. Finally, we demonstrate the performance of real-world applications of RotationNet trained with our newly created multi-view image dataset using a moving USB camera.

Complete Republication: Fall Injury while the Parent Is Operating a Bicycle with an Infant in a Baby Carrier.

INTRODUCTION: Pediatric emergency physicians commonly experience cases of infantile trauma as a result of a child falling from the arms or the back of a parent while the parent is operating a bicycle. METHODS: 1. We conducted a retrospective case-series study which included children younger than 1 year who were injured after falling from the arms or the back of the parent while the latter was operating a bicycle. 2. We conducted a dynamics experiment by recreating the circumstances of the accident using dummies representing a 6-month-old infant being carried on the back of the mother. We assessed the score of the Head Injury Criterion (HIC) and the maximum impact load on the head of the dummy infant. RESULTS: 1. We found eight injured patients, two of whom required intensive care. One of the latter experienced neurological sequelae. 2. The HIC score and the maximum impact load varied from 7.7 to 17.0 and 2.26 to 3.47 times the reference values for 6-month-old infants, respectively. CONCLUSIONS: Our study revealed that a strong impact on an infant's head can result in severe head trauma due to the mechanics of the injury type studied. Preventive strategies for the safe transportation of infants are needed.

Optical investigations of the (dis)continuous metal-insulator transitions in strongly-coupled electron-lattice systems.

Optical properties of four model systems (Na-, K-, Rb- or Cs-doped quasi-two-dimensional X 1.95Al1.95Si2.05O8.00; X = Na, K, Rb, or Cs) used to study the metal-insulator transition (MIT) in a deformable lattice are investigated. The doping evolution of the optical absorption band(s) originating from small bipolarons show strong variations depending on the electron-lattice coupling strength [Formula: see text]. Despite the increasing number density of small (bi)polarons, the Na-system remains a stubborn (bi)polaronic insulator due to strong [Formula: see text], while the other three systems show closing of the respective mobility gaps giving way to conducting phases with differing properties. These interesting evolutions and dynamical properties are compared and discussed. We conjecture that the manifestation of anomalous electronic transport properties and Mooij correlations near the MIT or superconductor-insulator transition in systems with non-negligible electron-lattice coupling effects may be linked to the coexistence of competing polaronic phases and the dynamical intertwining of the deformable lattice and the random electronic potential.

Equivalent Circuit Model Viewed From Receiver Side in Human Body Communication.

Human body communication (HBC) is a signal transmission method that uses the human body as a part of the transmission path. The incoming signal through the receiver electrode can be modeled as a signal from a signal source, which consists of the equivalent signal source voltage and output impedance. These values are important parameters for analyzing the transmission characteristics of HBC as well as for designing the front-end circuit of the receiver. In this paper, an equivalent circuit model of signal transmission from a transmitter on the human body to an off-body receiver touched by a finger was constructed. The ground electrode of the transmitter was in contact with the human body. This is a different configuration compared to capacitive HBC configurations that leave the ground electrode floating. The relationship between the received signal voltage and the distance between the transmitter's electrodes, the size of the receiver ground, and the transmitter-receiver distance were evaluated. Results were analyzed by using the equivalent circuit model. The transmitter-receiver distance and the distance between the transmitter's electrodes were both independently related to the equivalent signal source voltage. The receiver ground size which was related to the capacitive coupling between the receiver ground and the human body was related to the equivalent output impedance.

Differences in biomechanical properties and thickness among frontal and parietal bones in a Japanese sample.

The aim of this study was to assess the mechanical properties and thickness of adult frontal and parietal bones. The heads of 114 Japanese cadavers (78 male cadavers and 36 female cadavers) of known age and sex were used. A total of 912 cranial samples, 8 from each skull, were collected. Samples were imaged using multidetector computed tomography to measure sample thickness. The fracture load of each sample was measured using a bending test with calculation of flexural strength. Statistical analyses demonstrated no significant bilateral difference in either the mechanical properties or thickness of frontal or parietal bones. The mechanical properties and thicknesses of frontal bones were significantly greater than those of parietal bones regardless of sex. Therefore, the skull may have a great ability to resist frontal impacts compared with parietal impacts. In female samples, parietal bones were found to have a more uniform structure when compared with male samples. Male parietal bones were found to be thicker at medial sites than at lateral sites. This study also revealed parietal bones at lateral sites in female samples were thicker than in male samples. No strong association was observed between age and flexural strength of frontal or parietal bones. However, the fracture load was negatively correlated with age most likely due to the reduction of thickness.

Statistical analysis of biomechanical properties of the adult sagittal suture using a bending method in a Japanese forensic sample.

This study examined the mechanical properties of the adult sagittal suture compared with surrounding parietal bones using bending tests and investigated the association between the mechanical properties of the suture and age. We used the heads of 116 Japanese cadavers (76 male cadavers and 40 female cadavers) of known age and sex. A total of 1160 cranial samples, 10 from each skull, were collected. The samples were imaged using multidetector computed tomography, and the sample thickness at the center of each sample (ST) was measured. The failure stress of each sample (FS) was measured by a bending test, and the ratio of failure stress to the square of sample thickness (FS/ST(2)) was calculated. Statistical analyses revealed that the FS and FS/ST(2) values were significantly lower at all suture sites than at all bone sites regardless of sex. There were not significant but slight positive correlations between age and FS and FS/ST(2) values at any suture site in male samples. In female samples, age had significant positive correlations with FS and FS/ST(2) values at the middle suture sites, whereas there were not significant but slight positive correlations between age and FS and FS/ST(2) values at the edges of the suture. Statistical analyses also demonstrated that FS and FS/ST(2) values were significantly greater in male samples than in female samples at the middle suture sites. These findings suggest that the bending strength of the adult sagittal suture is significantly lower than that of surrounding parietal bones. Therefore, avoiding direct impact on cranial sutures may be important for preventing skull fractures and severe complications that can cause death. The results of this study also revealed that the bending strength of the middle sagittal suture significantly increases with age in only female samples, whereas the bending strength is significantly higher in male samples than in female samples at the middle suture sites, indicating the possibility of sex difference in the bony interdigitation of the sutures during childhood.

Effects of the freezing and thawing process on biomechanical properties of the human skull.

The aim of this study was to determine if biomechanical investigations of skull samples are reliable after skulls have been subjected to a freezing and thawing process. The skulls were obtained from 105 Japanese cadavers (66 males, 39 females) of known age that were autopsied in our department between October 2012 and June 2013. We obtained bone specimens from eight sites (four bilaterally symmetrical pairs) of each skull and measured the mass of each specimen. They were then classified into three groups (A, B, C) based on the duration of freezing of the experimental samples. The left-side samples were subjected to frozen storage (experimental group). The corresponding right-side samples were their controls. Bending tests were performed on the controls immediately after they were obtained. The experimental samples were preserved by refrigeration at -20 °C for 1 day (group A), 1 month (group B), or 3 months (group C). Following refrigeration, these samples were placed at 37 °C to thaw for 1 h and then were subjected to bending tests using a three-point-bending apparatus attached to a Handy force gauge. The device recorded the fracture load automatically when the specimen fractured. Statistical analyses revealed that there were no significant differences in sample fracture loads between the frozen preserved/thawed samples and the unfrozen controls for each of the cryopreservation intervals. We eliminated any possible sample mass bias by using controls from the same skull in each case. The results suggest that the freezing/thawing process has little effect on the mechanical properties of human skulls. Thus, frozen storage for up to 3 months is a good method for preserving human skulls.

Statistical analysis of biomechanical properties of the adult skull and age-related structural changes by sex in a Japanese forensic sample.

The purpose of this research was to investigate the biomechanical properties of the adult human skull and the structural changes that occur with age in both sexes. The heads of 94 Japanese cadavers (54 male cadavers, 40 female cadavers) autopsied in our department were used in this research. A total of 376 cranial samples, four from each skull, were collected. Sample fracture load was measured by a bending test. A statistically significant negative correlation between the sample fracture load and cadaver age was found. This indicates that the stiffness of cranial bones in Japanese individuals decreases with age, and the risk of skull fracture thus probably increases with age. Prior to the bending test, the sample mass, the sample thickness, the ratio of the sample thickness to cadaver stature (ST/CS), and the sample density were measured and calculated. Significant negative correlations between cadaver age and sample thickness, ST/CS, and the sample density were observed only among the female samples. Computerized tomographic (CT) images of 358 cranial samples were available. The computed tomography value (CT value) of cancellous bone which refers to a quantitative scale for describing radiodensity, cancellous bone thickness and cortical bone thickness were measured and calculated. Significant negative correlation between cadaver age and the CT value or cortical bone thickness was observed only among the female samples. These findings suggest that the skull is substantially affected by decreased bone metabolism resulting from osteoporosis. Therefore, osteoporosis prevention and treatment may increase cranial stiffness and reinforce the skull structure, leading to a decrease in the risk of skull fractures.

Development of childhood fall motion database and browser based on behavior measurements.

This paper describes the development of a fall motion database and a browser designed to facilitate investigations into fall-related injury risk. First, child-related daily activities were collected at a "sensor home", which is a model of a normal living environment equipped with an embedded video-surveillance system and within which child test subjects were equipped with wearable acceleration-gyro sensors. As of this report, measurements have been conducted for 19 children (months age: mean=23.8, standard deviation=10.5), and data has been obtained on 105 fall incidents. During our research, falls were detected from the accumulated sensor data using a detection algorithm developed by the authors, and then video clips of detected falls were extracted from the recorded video streams automatically. The extracted video clips were then used for fall motion analysis. A computer vision (CV) algorithm, which was developed to automate fall motion analysis, facilitates accumulation of fall motion data into the abovementioned database, and the associated database browser allows users to perform conditional searches of fall data by inputting search conditions, such as child attributes and specific fall situations. Before this study, there was no database which contains child's actual fall motion data, and it has the potential to facilitate injury risk reduction related to falls in daily living environments.

Performance Improvement of a Return Channel in a Multistage Centrifugal Compressor Using Multiobjective Optimization.

The effect of the design parameters of a return channel on the performance of a multistage centrifugal compressor was numerically investigated, and the shape of the return channel was optimized using a multiobjective optimization method based on a genetic algorithm to improve the performance of the centrifugal compressor. The results of sensitivity analysis using Latin hypercube sampling suggested that the inlet-to-outlet area ratio of the return vane affected the total pressure loss in the return channel, and that the inlet-to-outlet radius ratio of the return vane affected the outlet flow angle from the return vane. Moreover, this analysis suggested that the number of return vanes affected both the loss and the flow angle at the outlet. As a result of optimization, the number of return vane was increased from 14 to 22 and the area ratio was decreased from 0.71 to 0.66. The radius ratio was also decreased from 2.1 to 2.0. Performance tests on a centrifugal compressor with two return channels (the original design and optimized design) were carried out using two-stage test apparatus. The measured flow distribution exhibited a swirl flow in the center region and a reversed swirl flow near the hub and shroud sides. The exit flow of the optimized design was more uniform than that of the original design. For the optimized design, the overall two-stage efficiency and pressure coefficient were increased by 0.7% and 1.5%, respectively. Moreover, the second-stage efficiency and pressure coefficient were respectively increased by 1.0% and 3.2%. It is considered that the increase in the second-stage efficiency was caused by the increased uniformity of the flow, and the rise in the pressure coefficient was caused by a decrease in the residual swirl flow. It was thus concluded from the numerical and experimental results that the optimized return channel improved the performance of the multistage centrifugal compressor.

A concept of needs-oriented design and evaluation of assistive robots based on ICF.

In the robotics community, a great number of assistive robots for elderly and handicapped people have been developed in the past few decades. However, very few of them became commercially available. It is often claimed that the major problems for the commercialization of robotic technologies are the "cost" and the "safety." However we believe that the mismatch of "needs in daily lives" and "seeds in the technologies" is also a major problem. In this paper, we describe our novel ideas on the development of assistive robots which fit the real needs of users based on ICF (International Classification of Functioning, Disability and Health), which is a part of the WHO Family of International Classifications for describing whole activities of a person in daily lives. By utilizing ICF, the development process of assistive robots - analyzing and discovering needs in daily lives, designing robots and evaluating the products - will be achieved in an objective manner.