1,579 research outputs found
Effect of Sex and Lateral Ankle Sprain History on Dorsiflexion Range Of Motion Asymmetry During the Weight Bearing Lunge Test
© 2024 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International License (CC BY-NC), https://creativecommons.org/licenses/by-nc/4.0/Background Reduced dorsiflexion range of motion (DFROM) which is commonly seen following lateral ankle sprain (LAS) has the potential to influence lower extremity biomechanics which have been linked to increased injury risk in the female athlete. Current research on the effect of sex and LAS history on DFROM is limited. Hypothesis/Purpose This study had three aims 1) to determine the effect of sex, leg dominance and LAS history on DFROM, 2) to determine the effect of sex and LAS history on magnitude of DFROM symmetry and 3) to examine the association of sex on direction (whether dominant or non-dominant limb had the higher DFROM) of symmetry. Study Design Cross-Sectional Study Methods DFROM was measured bilaterally in 105 recreational athletes all participating in multidirectional sports using the tape measurement method during the weight bearing lunge test (WBLT). A mean of three measurements was used for analysis. A 3-way mixed ANOVA was carried out to determine the interaction between sex, LAS history and leg dominance on DFROM and a 2-way ANOVA for the effect of sex and LAS history on asymmetry. A chi-square test was used to determine the association of sex and direction of asymmetry. Results The results indicate no significant effect of sex, LAS history, and leg dominance on DFROM (p=0.65). Main effects were significant for sex and LAS on DFROM. The mean asymmetry for all participants was reported as 12.25±14.76cm. No significant effect of sex and LAS history on magnitude of asymmetry was reported. There was a significant association of sex and direction of asymmetry (χ2(1) = 11.26, p = 0.00). Sixty-five-point two percent of males were shown to have higher DFROM of their non-dominant limb compared to 75% of females who were higher in their dominant limb. Conclusion Findings from this study suggest that DFROM is affected by sex and LAS history. While females have increased DFROM compared to males, those with LAS history are more likely to have a decreased DFROM on the involved side. The results also indicate that interlimb asymmetries in DFROM are present in athletes, therefore practitioners should exercise caution when using bilateral comparisons in injury and return to play assessments.Peer reviewe
Microfluidic Platform for the Elastic Characterization of Mouse Submandibular Glands by Atomic Force Microscopy
The ability to characterize the microscale mechanical properties of biological materials has the potential for great utility in the field of tissue engineering. The development and morphogenesis of mammalian tissues are known to be guided in part by mechanical stimuli received from the local environment, and tissues frequently develop to match the physical characteristics (i.e., elasticity) of their environment. Quantification of these material properties at the microscale may provide valuable information to guide researchers. Presented here is a microfluidic platform for the non-destructive ex vivo microscale mechanical characterization of mammalian tissue samples by atomic force microscopy (AFM). The device was designed to physically hold a tissue sample in a dynamically controllable fluid environment while allowing access by an AFM probe operating in force spectroscopy mode to perform mechanical testing. Results of measurements performed on mouse submandibular gland samples demonstrate the ability of the analysis platform to quantify sample elasticity at the microscale, and observe chemically-induced changes in elasticity
Morphological Biosignatures and the Search for Life on Mars
This report provides a rationale for the advances in instrumentation and understanding needed to assess claims of ancient and extraterrestrial life made on the basis of morphological biosignatures. Morphological biosignatures consist of bona fide microbial fossils as well as microbially influenced sedimentary structures. To be recognized as evidence of life, microbial fossils must contain chemical and structural attributes uniquely indicative of microbial cells or cellular or extracellular processes. When combined with various research strategies, high-resolution instruments can reveal such attributes and elucidate how morphological fossils form and become altered, thereby improving the ability to recognize them in the geological record on Earth or other planets. Also, before fossilized microbially influenced sedimentary structures can provide evidence of life, criteria to distinguish their biogenic from non-biogenic attributes must be established. This topic can be advanced by developing process-based models. A database of images and spectroscopic data that distinguish the suite of bona fide morphological biosignatures from their abiotic mimics will avoid detection of false-positives for life. The use of high-resolution imaging and spectroscopic instruments, in conjunction with an improved knowledge base of the attributes that demonstrate life, will maximize our ability to recognize and assess the biogenicity of extraterrestrial and ancient terrestrial life
Arrival directions of cosmic rays of E .4 EeV
The anisotropy of cosmic rays observed by the Utah Fly's Eye detector has been studied. Emphasis has been placed on examining distributions of events in galactic coordinates. No statistically significant departure from isotropy has been observed for energies greater than 0.4 EeV (1 EeV = 10 to the 18th power eV). Results of the standard harmonic analysis in right ascension are also presented
Microstructural origin for the piezoelectricity evolution in (K0.5Na0.5)NbO3-based lead-free ceramics
Chemically modified (K0.5Na0.5)NbO3 compositions with finely tuned polymorphic phase boundaries (PPBs) have shown excellent piezoelectric properties. The evolution of the domain morphology and crystal structure under applied electric fields of a model material, 0.948(K0.5Na0.5)NbO3-0.052LiSbO3, was directly visualized using in situ transmission electron microscopy. The in situ observations correlate extremely well with measurements of the electromechanical response on bulk samples. It is found that the origin of the excellent piezoelectric performance in this lead-free composition is due to a tilted monoclinic phase that emerges from the PPB when poling fields greater than 14 kV/cm are applied. 2013 AIP Publishing LLC
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