The Relationship Between Biomechanical-Anthropometrical Parameters and the Force Exerted on the Head When Heading Free Kicks in Soccer

Background: Soccer is a contact sport in which the players are frequently faced with the risk of injury. It has been shown that the force exerted on the head during heading can be as much as 500–1200 Newton (N). Objectives: The main objective of this study was to determine whether there was any relationship between the force exerted on the head and several biomechanical and anthropometrical parameters related to heading free kicks. Patients and Methods: A total of 16 semi-professional soccer players with at least 5 years experience participated in this study. The mean age, height, and weight of the study participants were 21.36 ± 5.67, 178 ± 5.99 cm, and 70.55 ± 8.55 kg, respectively. To measure the force exerted on the heads of the players, a pressure gauge was installed on their foreheads. Each participant was asked to defend the ball using the heading technique three times. A camera with a sampling frequency of 150 frames per second was used to record the moment of impact between the ball and head during each heading event. For each participant and replicate, the ball and head velocity (m/s) as well as the angular body changes (degrees) were calculated using MATLAB and AutoCAD softwares, respectively. Descriptive statistics, including means and standard deviations were used to describe the data. Pearson correlation coefficient (alpha = 0.05) was used to examine potential relationships between the variables of interest. Results: Significant correlations existed between the force exerted on the head during heading, participant age, body mass, body fat percentage, and head perimeter (P < 0.05). Conclusions: The study revealed the significance of anthropometric variables related to heading, such as age and head perimeter. Therefore, it was concluded that these variables should be considered when teaching and practicing the heading technique with players of different ages and anthropometric sizes

The impact of the number of tears in patient-specific Stanford type B aortic dissecting aneurysm: CFD simulation

It is believed that the progression of Stanford type B aortic dissection is closely associated with vascular geometry and hemodynamic parameters. The hemodynamic differences owing to the presence of greater than two tears have not been explored. The focus of the present study is to investigate the impact of an additional re-entry tear on the flow, pressure and wall shear stress distribution in the dissected aorta. A 3D aorta model with one entry and one re-entry tear was generated from computed tomography (CT) angiographic images of a patient with Stanford Type B aortic dissection. To investigate the hemodynamic effect of more than two tear locations, an additional circular re-entry tear was added 24mm above the original re-entry tear. Our simulation results showed that the presence of an additional re-entry tear provided an extra return path for blood back to the true lumen during systole, and an extra outflow path into the false lumen during diastole. The presence of this additional path led to a decrease in the false lumen pressure, particularly at the distal region. Meanwhile, the presence of this additional tear causes no significant difference on the time average wall shear stress (TAWSS) distribution except at regions adjacent to re-entry tear 2. Moderate and concentrated TAWSS was observed at the bottom region of this additional tear which may lead to further extension of the tear distally

Calibration of multi-layered probes with low/high magnetic moments

We present a comprehensive method for visualisation and quantification of the magnetic stray field of magnetic force microscopy (MFM) probes, applied to the particular case of custom-made multi-layered probes with controllable high/low magnetic moment states. The probes consist of two decoupled magnetic layers separated by a non-magnetic interlayer, which results in four stable magnetic states: ±ferromagnetic (FM) and ±antiferromagnetic (A-FM). Direct visualisation of the stray field surrounding the probe apex using electron holography convincingly demonstrates a striking difference in the spatial distribution and strength of the magnetic flux in FM and A-FM states. In situ MFM studies of reference samples are used to determine the probe switching fields and spatial resolution. Furthermore, quantitative values of the probe magnetic moments are obtained by determining their real space tip transfer function (RSTTF). We also map the local Hall voltage in graphene Hall nanosensors induced by the probes in different states. The measured transport properties of nanosensors and RSTTF outcomes are introduced as an input in a numerical model of Hall devices to verify the probe magnetic moments. The modelling results fully match the experimental measurements, outlining an all-inclusive method for the calibration of complex magnetic probes with a controllable low/high magnetic moment

Evaluation of Survival Rate and Effective Factors in Acute Myocardial Infarction Patients in Emam Hospital (Year 2000)

Introduction: For the time being we have considered that the myocardial infarction is an increasing event in Islamic Republic of Iran and there are many procedures and methods which can help us to diminish the number of death from this ongoing event. The main aim of this research is to determine the survival rate in those patients who have had acute myocardial infarction and the association of it with different variables. Methods and Materials: The present research is a descriptive case-series study which evaluates the 100 cases of acute myocardial infarction who had been admitted in Tehran Emam Khomeini Hospital during the year 1999. Results: The mean age of patients was 57 years. The peak of attack rates was in spring and autumn. Investigating of the past history of these patients reviled that 41 percent had been smokers, 63.5 percent have had the history of previous ischemic heart disease, 41 percent have had hyper cholestrolemia, 34 percent had hypertension, 18 percent had diabetes mellitus, 9 percent had mitral rigurgitation and 9 percent had heart block. The Survival rate in our study has been calculated 68 percent in first 28 days of disease. Conclusion: In our study we concluded that there is significant correlation between survival rate and past history of hypertension, ischemic heart disease, tobacco smoking and clip classification

Calculation of probability of survival based on TRISS model in three hospitals in Tehran, 1996-97

Different aspects of the effect of trauma on the health status of populations have been studied annually 35 millions deaths, 3.5 millions disabilities and a sum of 500 billions $ cost. Evaluating different modes of prevention, a comprehensive study was carried out in the US during the 7th and 8th decades, introducing the TRISS method for the purpose of comparing the outcomes of trauma cases among multiple centers. This study has been carried out during 1996-97 in there hospitals of Tehran. After entering the hospital, all trauma cases were traced by trained interviewers until leaving the hospital. Based on the TRISS model, probability of survival was calculated for each patient and compared with the results of the MTOS study. Among 4863 cases evaluated, 300 (6.2%) deaths were observed, which is significantly more than the expected number (222 deaths, 2.7%) calculated under TRISS model. This difference may indicate a difference in the quality of trauma care

Effects of Inhalation Flow Rate on Particle Deposition and Flow Structure in a Model of Tracheobronchial Airway.

Due to the prevalence of respiratory diseases, effective drug delivery to the lungs is important for researchers. The main objective of current study is investigating the transfer and deposition of micron-sized particles (1-10 ?m) as well as airflow structure at different respiratory flow rates (i.e. 30, 60, and 90 L/min) in a realistic airway model according to the CT images of a 48-year-old healthy female. Computational fluid dynamics (CFD) is used for simulation of particle transport and deposition in an airway model that includes mouth-Throat zone, trachea region, and bronchial airways up to the fourth generation and the results were compared with available data in the literature. To investigate airflow structure, velocity contours with streamlines at different regions are obtained. Deposition fraction (DF) is used to present the results of particle deposition pattern. The results show that mouth-Throat region and trachea filters out largest inhaled aerosols, which lead to highest particle deposition fractions for these regions. In addition, increasing the inhalation flow rate, increases turbulence level and particles inertia which result in higher deposition fractions

Effect of laryngeal jet on dry powder inhaler aerosol deposition: A numerical simulation.

Although pulmonary drug delivery has been deeply investigated, the effect of the laryngeal jet on particle deposition during drug delivery with dry powder inhalers (DPI) has not been evaluated profoundly. In this study, the flow structure and particle deposition pattern of a DPI in two airway models, one with mouth-throat region including the larynx and the other one without it, are numerically investigated. The results revealed that the laryngeal jet has a considerable effect on particle deposition. The presence of laryngeal jet leads to 4-fold and 2-fold higher deposition efficiencies for inlet flow rates of 30 and 90 L/min, respectively