125 research outputs found
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
Prevalence of Integrons and Antibiotic Resistance Pattern in Acinetobacter baumannii Isolated from Clinical Samples of Iranian Patients: A Systematic Review and Meta-analysis
Background: Acinetobacter baumannii is an important opportunistic nosocomial pathogen. Class 1 integrons in A. baumannii plays a significant role in antibiotic resistance. Therefore, this study aimed to investigate the prevalence of integrons and antibiotic resistance pattern in A. baumannii isolated from clinical samples of Iranian patients. Methods: The Medical Subject Headings (MeSH) and the keywords with the help of Boolean operators ("AND" or "OR") were used alone or in combination to conduct the search. The searching process was conducted in the Web of Science, PubMed, Cochrane Library, Scopus, and Google Scholar databases and, also Iranian databases. The search was restricted to relevant English and Persian cross-sectional publications reporting the prevalence of Int1 in A. baumannii isolated from clinical samples from 1 January 2000 to 31 December 2018. The data were analyzed using Comprehensive Meta-Analysis software. Regarding the heterogeneity of studies, the random effects model was used. Cochrane Q and I2 tests was used to evaluate statistical heterogeneity between the studies. Results: Fifteen studies were included in the analysis. The combined prevalence of class 1 integrons in A. baumannii was 55.2 (95 CI: 44.8-65.1). The pooled prevalence of MDR A. baumannii isolates was 68.1. The highest resistance belonged to Aztreonam, followed by Ciprofloxacin, and Ceftazidime with a resistance rate of 97.6, 92.8, and 91.6, respectively. Tobramycin was reported as an effective antibiotic. Conclusions: The present study reported an alarmingly high prevalence of class 1 Integrons, and MDR isolates of A. baumannii recovered from clinical samples that should be considered. © 2019 Mehran G., et al
Asymmetric Exclusion Processes with Disorder: Effect of Correlations
Multi-particle dynamics in one-dimensional asymmetric exclusion processes
with disorder is investigated theoretically by computational and analytical
methods. It is argued that the general phase diagram consists of three
non-equilibrium phases that are determined by the dynamic behavior at the
entrance, at the exit and at the slowest defect bond in the bulk of the system.
Specifically, we consider dynamics of asymmetric exclusion process with two
identical defect bonds as a function of distance between them. Two approximate
theoretical methods, that treat the system as a sequence of segments with exact
description of dynamics inside the segments and neglect correlations between
them, are presented. In addition, a numerical iterative procedure for
calculating dynamic properties of asymmetric exclusion systems is developed.
Our theoretical predictions are compared with extensive Monte Carlo computer
simulations. It is shown that correlations play an important role in the
particle dynamics. When two defect bonds are far away from each other the
strongest correlations are found at these bonds. However, bringing defect bonds
closer leads to the shift of correlations to the region between them.Comment: 11 pages, 15 eps figures, RevtexI
Comparison of two pain assessment tools, �facial expression� and �critical care pain observation tool� in intubated patients after cardiac surgery
Background: Critical-care patients are at higher risk of untreated pain, because they are often unable to communicate owing to altered mental status, tracheal intubation and sedation. Objectives: This study compared two pain assessment tools on tracheal intubated critically ill patients in a cardiac post-anesthesia care unit, who were unable to communicate verbally. The studied tools were �critical-care pain observation tool (CPOT)� and �facial expression (FE)�. Patients and Methods: This was a prospective study based on diagnostic test evaluation. A sample of 91 intubated patients was selected from cardiac post-anesthesia care unit. Collected data were demographic characteristics, vital signs, FE and CPOT tools� scale. Pain was assessed with CPOT and FE scores five times. The first assessment was performed in at least 3 hours after admission of patients to ICU. Then, the pain intensity was reassessed every 30 minutes. In addition, blood pressure, heart rate, respiratory rate and oxygen saturation were measured simultaneously. Results: At the first period, the frequency of �severe� pain intensity using the CPOT was 58.2 and with the FE tool was 67 (P = 0.001). Both tools demonstrated reduction in severity of pain on second and third assessment times. Significantly increasing level of pain and blood pressure due to nursing painful procedures (endo-tracheal suctioning, changing patient�s position, etc.), were obtained by CPOT in fourth assessment. FE was not able to detect such important findings (κ = 0.249). In the fifth step, pain intensity was reduced. The most agreement between the two tools was observed when the reported pain was �severe� (κ = 0.787, P < 0.001) and �mild� (κ = 0.851, P < 0.001). Conclusions: The sensitivity of CPOT was higher for detection and evaluation of pain in intubated postoperative patients compared with �Facial Expression�. Best agreement between these tools was observed in two extremes of pain intensity. © 2016, Iranian Society of Regional Anesthesia and Pain Medicine (ISRAPM)
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Metamaterial boat fenders with supreme shape recovery and energy absorption/dissipation via FFF 4D printing
In maritime transportation, a fender acts like a bumper to absorb the kinetic energy of a boat berthing against a jetty, pier wall, or other boats. They have high energy absorption and low reaction forces, preventing damage to boats and berthing structures. The aim of this paper is to introduce a novel conceptual design for a new class of lightweight boat-fendering systems with superior energy absorption/dissipation and shape recovery features. Different metamaterials with honeycomb, re-entrant, and re-entrant chiral auxetic patterns are designed in the form of boat fender panels, and their thermo-mechanical behaviors are analyzed experimentally and numerically. A finite element modeling (FEM) is developed to investigate the compressive behaviors of boat fenders. Some of designs are 4D printed by fused filament fabrication of shape memory polylactic acid polymers and then tested thermo-mechanically. A good correlation is observed between numerical and experimental results, supporting the FEM accuracy. Results reveal that proposed boat fenders have considerable energy absorption/dissipation along with the capability to fully recover plastic deformations by simply heating up. The excellent mechanical property recovery of the proposed boat-fendering system is also shown under cycling loadings. Due to the absence of similar conceptual designs, models, and results in the specialized literature, this paper is expected to be instrumental towards 4D printing novel boat fenders with supreme energy absorption/dissipation and shape recovery properties promoting sustainability
Relationship among temporary separation, attachment styles, and adjustment in first-grade Iranian children
If mothers work outside the home, some degree of mother-child separation will be experienced and mother-child attachment will be affected. In this study, regarding the attachment styles, sociobehavioral problems in first-grade children with experience of preschool and in those taught by their mothers at-home are compared. A casual-comparative method was used to compare children in the two groups. A total of 320 first-grade children participated in the study. The study measures included a separation anxiety test, an adaptive behavior scale, and a children�s symptom inventory. Data were analyzed using multivariate statistics. Secure attachment in the group with experience of preschool was significantly higher than that in the at-home group. None of the variables, including parents� education and father�s income, significantly affected attachment style. Neither father�s education, father�s income, or attachment significantly influenced adjustment. Father�s education significantly influenced children�s symptoms. Attachment style and hours of preschool attendance had no effect on Child Symptom Inventory scores. Associations among age at joining preschool, attachment style, and behavioral and adaptive problems in first-grade children were nonlinear and multivariate. By taking into account parents� awareness, sensitivity, and responsiveness, relative welfare, appropriate quality of child-care centers, and having fewer hours of preschool attendance, the risk factors for early parent-child separation and institutional care can be reduced. © 2016 Tahmasebi et al
Antibiotic resistance, biofilm formation, and biofilm-associated genes among Stenotrophomonas maltophilia clinical isolates
Objective: The purpose of the present study was to investigate the antimicrobial susceptibility pattern, biofilm production, and the presence of biofilm genes among the S. maltophilia clinical isolates. A total of 85 clinical isolates of S. maltophilia were collected from patients referred to several hospitals. Susceptibility to antibiotics was investigated by disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). By the crystal violet staining method, the capability of biofilm formation was examined. The genes associated with biofilm production were investigated by the PCR-sequencing techniques. Results: All isolates were resistant to doripenem, imipenem, and meropenem. Minocycline, trimethoprim/sulfamethoxazole and levofloxacin exhibited the highest susceptibility of 100, 97.65, and 95.29, respectively. The results of crystal violet staining assay showed that all isolates (100) form biofilm. Moreover, 24 (28.23), 32 (37.65), and 29 (34.12) of isolates were categorized as weak, moderate, and strong biofilm producers, respectively. Biofilm genes including rpfF, spgM and rmlA had an overall prevalence of 89.41 (76/85), 100 (85/85) and 84.71 (72/85), respectively. Rational prescribing of antibiotics and implementation of infection control protocols are necessary to prevent further infection and development of antimicrobial resistance. Combination strategies based on the appropriate antibiotics along with anti-biofilm agents can also be selected to eliminate biofilm-associated infections. © 2021, The Author(s)
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