The purposes of this study were to compare Young’s modulus values determined by shear wave ultrasound elastography (SWUE) with stiffness index obtained using a hand-held MyotonPRO device on the resting stiffness of gastrocnemius muscle belly and Achilles tendon; and to examine the test-retest reliability of those stiffness measurement using hand-held MyotonPRO. Twenty healthy volunteers participated in the study. The measurement values of muscle and tendon was determined in dominant legs. Each marker point was assessed using MyotonPRO and SWUE, respectively. Intra-operator reliability of MyotonPRO was established in 10 of the subjects. The correlation coefficients between the values of muscle and tendon stiffness indices determined by MyotonPRO and SWUE were calculated. Significant correlations were found for muscle and tendon stiffness and Young’s modulus ranged from 0.463 to 0.544 (all P < 0.05). The intra-operator reliability ranged from good to excellent (ICC(3,1) = 0.787~0.928). These results suggest that the resting stiffness of gastrocnemius muscle belly and Achilles tendon measured by MyotonPRO is related to the Young’s modulus of those quantified by SWUE. The MyotonPRO shows good intra-operator repeatability. Therefore, the present study shows that MyotonPRO can be used to assess mechanical properties of gastrocnemius muscle belly and Achilles tendon with a resting condition.
There is currently great interest in enzyme immobilization to enhance enzyme stability and reusability, and to aid in separation from the reaction mixture, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] but immobilized enzymes on commonly used inorganic and organic solid supports show low activities. This is a result of the leaching of the enzymes from the solid supports and the limited conformational transitions available to the enzymes for chemical interaction on the supports. [1][2][3][4] Enzymes encapsulated by a sol-gel/polymer [3][4][5][6][7][8][9][10] show good activity, but the wide pore-size distribution in sol-gel/polymers cannot be well controlled, and this adversely influences the diffusion of reactants and products during biocatalysis to the detriment of their practical application. [3,4,16] Recently, a number of successful examples of good enzyme activity resulting from enzyme immobilization in uniform mesopores of ordered mesostructured materials have been reported. [14][15][16][17] However, enzyme immobilization in mesopores is limited by the pore size of the mesostructured materials, so that bulky enzymes or enzyme aggregates larger than the mesopores cannot be immobilized. A general and facile approach for the encapsulation of enzymes of various sizes in ordered mesoporous silica is reported here, where the enzymes are entrapped in macroporous cages connected by uniform mesoporous channels. These encapsulated enzymes show good activity, long-term stability, and excellent recycling characteristics. The concept of "fish-in-net" encapsulation of enzymes in ordered mesoporous silica under mild conditions is illustrated in Figure 1. Tetraethylorthosilicate (TEOS) was first assembled from a triblock ethylene oxide (EO)/propylene oxide (PO) copolymer surfactant ( EO 20 PO 70 EO 20 , P123) in ethanol. After evaporation of the ethanol and addition of glycerol, preformed precursors with ordered mesostructured silica particles were obtained in the glycerol solution, which is a non-denaturing solvent for enzymes. The preformed precursors were mixed with the enzyme solution under stirring at 4°C. During the interaction between the enzymes and the preformed precursors, active enzymes (acting as the "fish") were gradually entrapped in the "net" formed by the polymerization and condensation of the ordered mesostructured silica particles. After removal of the glycerol and water by evacuation, the xerogels with encapsulated enzymes were washed with ethanol and water several times to remove polymer surfactants in the mesopores. In contrast to the "ship-in-a-bottle" technique, [18] the enzymes in this work were used as templates for the
Single-case experimental design (SCED) research plays an important role in establishing and confirming evidence-based practices. Due to multiple measures of a target behavior in such studies, missing information is common in their data. The expectation-maximization (EM) algorithm has been successfully applied to deal with missing data in between-subjects designs, but only in a handful of SCED studies. The present study extends the findings from Smith, Borckardt, and Nash (2012) and Velicer and Colby (2005b, Study 2) by systematically examining the performance of EM in a baseline-intervention (or AB) design under various missing rates, autocorrelations, intervention phase lengths, and magnitudes of effects, as well as two fitted models. Three indicators of an intervention effect (baseline slope, level shift, and slope change) were estimated. The estimates' relative bias, root-mean squared error, and relative bias of the estimated standard error were used to assess EM's performance. The findings revealed that autocorrelation impacted the estimates' qualities most profoundly. Autocorrelation interacted with missing rate in impacting the relative bias of the estimates, impacted the root-mean squared error nonlinearly, and interacted with the fitted model in impacting the relative bias of the estimated standard errors. A simpler model without autocorrelation can be used to estimate baseline slope and slope change in time-series data. EM is recommended as a principled method to handle missing data in SCED studies. Two decision trees are presented to assist researchers and practitioners in applying EM. Emerging research directions are identified for treating missing data in SCED studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.