The Relationship Betweeen Dynamic and Chemical Factors on the Morphology in AOT-Water-Polymer Systems

Photopolymerization of reverse microemulsion demonstrates strong influences from dynamical and chemical factors on morphology of formed polymer systems. Upon polymerization the clear microemulsion with nanoscale structures transforms into opaque films with larger aggregates that scatter light. Studied here were microemulsions based on acrylate and on thiol-ene chemistries. The difference in the two reaction mechanisms results in the phase separation occurring at different stages of the material formation. Consequently, the morphology of the material demonstrates distinct dissimilarities in the two systems. In addition, the chemical structure of the monomers promotes these morphological differences. When the microemulsion is composed of acrylate and diacrylate monomers, the formed polymer has two different structures. Large sphere-shaped structures are formed from the aggregation of the nanometer-sized droplets in the microemulsion. The droplets, which are mainly filled with water, are large enough to scattering visible light and give the films their opacity. However, they are too small to be observable under an optical microscope. Secondly, some portion of the surfactant self-assembles into a bilayer structure connecting the larger pools of water. The structure of the film was evaluated by Small Angle Neutron Scattering and Ultra-Small Angle Neutron Scattering. In the case of microemulsions based on thiol-ene chemistry, the film\u27s morphology is considerably different. Large droplets with size varying from 2 to 100 um are visible in the films under the magnification of the optical microscope. In addition, the surfactant is more readily excluded from the polymer network than with acrylates; thus, the aggregates are filled not only with water but also with so-called aqueous phase composed of water and surfactant. The morphology of both systems is sensitive to the rate of the polymerization. The thiol-ene microemulsions were able to self-polymerize, which resulted in phase separation of the material. Resulting two layers were analyzed. The top layer contained mainly polymer. The lower stratum was water-rich with a small amount of polymer confined in droplets. This result proved that films formed through light induced reaction are frozen in a far-form-equilibrium state

Features of Extrinsic Plantar Muscles in Patients with Plantar Fasciitis by Ultrasound Imaging: A Retrospective Case Control Research

[Abstract] The present study aimed to compare by ultrasound imaging (USI) the tibial posterior (TP), medial gastrocnemius (MG) and soleus muscle in patients with and without plantar fasciitis (PF). A sample of 42 individuals was recruited and divided into two groups: PF and a healthy group. The thickness, cross-sectional area (CSA), echointensity and echovariation were assessed in both groups by USI. TP, soleus and MG variables did not report differences (p > 0.05) for thickness and CSA. For the echotexture parameters significant differences were found for MG echointensity (p = 0.002), MG echovariation (p = 0.002) and soleus echointensity (p = 0.012). Non-significant differences (p > 0.05) were reported for soleus echovariation, TP echointensity and TP echovariation variables. The thickness and CSA of the TP, GM and soleus muscle did not show significant differences between individuals with and without PF measured by USI. Muscle quality assessment reported an increase of the MG echointensity and echovariation, as well as a decrease of echointensity of the soleus muscle in the PF group with respect to the healthy group. Therefore, the evaluation of the structure and muscle quality of the extrinsic foot muscles may be beneficial for the diagnosis and monitoring the physical therapy interventions

Sports Performance Tests for Amputee Football Players: A Scoping Review

Background: This scoping review aims to identify sports performance tests for amputee football players and to critically analyze the methodological quality, validation data, reliability, and standardization of sport-specific tests to indicate the best-fitting tests. Methods: Electronic database searches were conducted between January 2019 and October 2021. Twelve articles met the inclusion criteria. Qualitative assessment of each study was conducted by STROBE checklist. Results: Twenty-nine sports performance tests were identified. No sports performance test fully met all three criteria associated with the qualitative assessment of tests. The critical appraisal of the articles demonstrates a gap in study design, settings, and main results description. Some inconsistencies were found in the methodological descriptions of tests assessing the same motor skill. A STROBE score of 13 points was considered a satisfactory score for the article (it was obtained by 8 of the 12 studies). The weakest point of the analyzed studies was the description of how the test group size was accessed and later obtained. Conclusions: No test was found that was simultaneously presented as valid, reliable, and standardized. The authors can recommend the use of the two-sports performance tests that are the closest to ideal: the L test and the YYIRT1

Neutron Scattering Study of the Structural Change Induced by Photopolymerization of AOT/D(2)O/Dodecyl Acrylate Inverse Microemulsions

Small-angle and ultrasmall-angle neutron scattering (SANS/USANS) measurements were used to determine the structural changes induced by photopolymerization of AOT/D2O/(dodecyl acrylate) inverse microemulsion systems. Scattering profiles were collected for the initial microemulsions and the films resulting from photopolymerization of the oil phase. The SANS data for the microemulsions were modeled as spherical, core−shell droplets. Upon polymerization, the clear mircoemulsions formed opaque films. From the SANS/USANS data of the films, it was apparent that this morphology was not preserved upon polymerization; however, it was clearly observed that the formulation of the microemulsion had a large impact on the structure within the films. The Guinier region in the USANS data (2.5 × 10−5 Å−1 ≤ Q ≤ 5.3 × 10−3 Å−1) from the films indicates that very large structures are formed. Simultaneously, a well-defined peak (0.15 Å−1 ≤ Q ≤ 0.25 Å−1) in the SANS data indicates that there are also much smaller structures formed. It is proposed that the low-Q scattering arises from aggregation of the nanometer-size water droplets in the microemulsion to form droplets large enough to scatter visible light, while the peak in the high-Q region results from bilayered structures formed by the surfactant

Using Ecological Momentary Assessment to Evaluate Current Physical Activity

Objective. The purpose of this study was to assess the value of ecological momentary assessment in evaluating physical activity among children, adolescents, and adults. It also determines whether ecological momentary assessment fulfills the criteria of validity, reliability, objectivity, norms, and standardization applied to the tools used for the evaluation of physical activity. Methods. The EBSCO-CINHAL, Medline, PsycINFO, PubMed, and SPORTDiscuss databases were reviewed in December 2012 for articles associated with EMA. Results. Of the 20 articles examined, half (10) used electronic methods for data collection, although various methods were used, ranging from pen and paper to smartphone applications. Ten studies used objective monitoring equipment. Nineteen studies were performed over 4 days. While the validity of the EMA method was discussed in 18 studies, only four found it to be objective. In all cases, the EMA procedures were precisely documented and confirmed to be feasible. Conclusions. Ecological momentary assessment is a valid, reliable, and feasible approach to evaluate activity and sedentary behavior. Researchers should be aware that while ecological momentary assessment offers many benefits, it simultaneously imposes many limitations which should be considered when studying physical activity

Humidity-Responsive Polymeric Films Based on AOT - Water Reverse Microemulsions

Hydrophobic polymer films, having an aqueous phase distributed throughout the matrix, were formed by polymerizing a solution of dodecyl acrylate and 1,6 hexanediol diacrylate containing nanometer-sized drops of water stabilized by sodium bis(2-ethylhexyl) sulfosuccinate (ACT). Photopolymerization-incluced aggregation of the water drops and/or phase separation occurred, as the initially clear solutions became opaque films. The polymerized films became clear, as the relative humidity was reduced. Clear films still contained 20-50% of the initial water. The transition from opaque to clear films was reversible provided that the film did not become completely dry and form cracks. (c) 2007 Wiley Periodicals, Inc

Green Synthesis and Characterization of Zinc Oxide Nanoparticles Using Larrea tridentata Extract and Their Impact on the In-Vitro Germination and Seedling Growth of Capsicum annuum

The application of green methods in the synthesis of nanoparticles using plants is a cost-effective and eco-friendly approach. Zinc oxide nanoparticles are of great importance due to their versatile properties. The conditions of synthesis strongly influence the characteristics and functionality of the nanoparticles. The present work studied the biological, green synthesis of zinc oxide nanoparticles (ZnONPs) in the presence of different concentrations of ethanolic extract of Larrea tridentata (10, 20, and 30 mg/mL). The time of the formation of nanoparticles was evaluated at different temperatures and pH values of the reaction medium. The formation of ZnONPs was confirmed by ultraviolet-visible (UV-Vis) and Fourier transform infrared spectroscopies (FT-IR), as well as scanning electron microscopy (SEM). X-ray diffraction analysis (XDR) determined the crystallographic structure of the nanoparticles. Obtained ZnONPs had a size range of 18 to 40 nm. The temperature, reaction time, and pH significantly influenced the nanoparticles’ morphology, size, and aggregation. The impact of chosen ZnONPs was tested on the germination of serrano chili seeds (Capsicum annuum). At 100 ppm, the nanoparticles improved germination percentage, vigor, and seedlings’ growth parameters