An examination of the self-referent executive processing model of test anxiety: control, emotional regulation, self-handicapping, and examination performance

According to the self-referent executive processing (S-REF) model, test anxiety develops from interactions between three systems: executive self-regulation processes, self-beliefs, and maladaptive situational interactions. Studies have tended to examine one system at a time, often in conjunction with how test anxiety relates to achievement outcomes. The aim of this study was to enable a more thorough test of the S-REF model by examining one key construct from each of these systems simultaneously. These were control (a self-belief construct), emotional regulation through suppression and reappraisal (an executive process), and self-handicapping (a maladaptive situational interaction). Relations were examined from control, emotional regulation, and self-handicapping to cognitive test anxiety (worry), and subsequent examination performance on a high-stakes test. Data were collected from 273 participants in their final year of secondary education. A structural equation model showed that higher control was indirectly related to better examination performance through lower worry, higher reappraisal was indirectly related to worse examination performance through higher worry, and higher self-handicapping was related to worse examination performance through lower control and higher worry. These findings suggest that increasing control and reducing self-handicapping would be key foci for test anxiety interventions to incorporate. © 2018 The Author(s

[[alternative]]The natural medications for wound healing - Curcumin, Aloe-Vera and Ginger - do not induce a significant effect on the migration kinematics of cultured fibroblasts

[[abstract]]Curcumin, Aloe-vera and Ginger are popular natural medications (NMs) for treating wounds, however, the mechanisms by which these NMs apparently accelerate wound healing remain largely unknown. From a biomechanical perspective, it is specifically unclear whether fibroblast motility improves in the presence of any of these NMs. Here we use our recently developed quantitative high-precision automated assay for cell migration (Topman et al., 2012b) which is based on image processing of time lapse micrographs to determine whether kinematic parameters e.g. the maximum and average migration rates of en mass fibroblast colonies are influenced by treating the cells with the above NMs. We found no evidence that Curcumin, Aloe-vera and Ginger directly influence the en mass fibroblast migration kinematics in vitro post infliction of localized mechanical damage to the cultures. However, due to the complexity of a wound healing process in vivo, these NMs may still influence the healing through other pathways

A new technique for studying directional cell migration in a hydrogel-based three-dimensional matrix for tissue engineering model systems

[[abstract]]Cell migration has a key role in biological processes e.g. malignancy, wound healing, immune response and morphogenesis. Studying migration and factors that influence it is beneficial e.g. for developing drugs to suppress metastasis, heal wounds faster or enhance the response to infection. Though the majority of the literature describes two-dimensional (2D) migration studies in culture dishes, a more realistic approach is to study migration in three-dimensional (3D) constructs. However, simple-to-implement, straight-forward standardized quantitative techniques for analysis of migration rates of cell colonies in 3D are still required in the field. Here, we describe a new model system for quantifying directional migration of colonies in a hyaluronic acid (oxi-HA) and adipic acid dihydrazide (ADH) hydrogel-based 3D matrix. We further demonstrate that our previously-reported image processing technique for measuring migration in 2D (Topman et al., 2011; 2012) is extendable for analyzing the rates of migration of cells that directionally migrate in the hydrogel and are fluorescently-stained with a 4’,6-diamidino-2-phenylindole (DAPI) nuclear stain. Together, the present experimental setup and image processing algorithm provide a standard test bench for measuring migration rates in a fully-automated, robust assay which is useful for high-throughput screening in large-scale drug evaluations, where effects on migration in a 3D matrix are sought

The influence of ischemic factors on the migration rates of cell types involved in cutaneous and subcutaneous pressure ulcers

[[abstract]]A pressure ulcer (PU) is a localized injury to the skin and/or to underlying tissues, typically over a weight-bearing bony prominence. PUs often develop in ischemic tissues. Other than being relevant to the etiology of PUs, ischemic factors such as glucose levels, acidity and temperature could potentially affect healing processes as well, particularly, the rate of damage repair. Using an in vitro cell culture model, the goal of the present study was to determine the influence of ischemic factors: low temperature (35 °C), low glucose (1 g/L) and acidic pH (6.7) on the migration rate of NIH3T3 fibroblasts, 3T3L1 preadipocytes and C2C12 myoblasts, which could all be affected by PUs. Cell migration into a local damage site, produced by crushing cells under a micro-indentor, was monitored over ~16 h under controlled temperature and pH conditions. We found that in the NIH3T3 cultures, acidosis significantly hindered the migration rate as well as delayed the times for onset and end of mass cell migration. The effects of temperature and glucose however were not significant. Additionally, under control conditions (temperature 37 °C, glucose 4.5 g/L, pH 7.6), migration rates and times differed significantly across the different cell types. The present findings motivate further studies related to the effects of pH levels on migration performances, particularly in PU where bacterial contamination-associated with an acidic environment-is involved

Sensitivity of Edge Detection Methods for Quantifying Cell Migration Assays

Quantitative imaging methods to analyze cell migration assays are not standardized. Here we present a suite of two-dimensional barrier assays describing the collective spreading of an initially-confined population of 3T3 fibroblast cells. To quantify the motility rate we apply two different automatic image detection methods to locate the position of the leading edge of the spreading population after [Image: see text], [Image: see text] and [Image: see text] hours. These results are compared with a manual edge detection method where we systematically vary the detection threshold. Our results indicate that the observed spreading rates are very sensitive to the choice of image analysis tools and we show that a standard measure of cell migration can vary by as much as 25% for the same experimental images depending on the details of the image analysis tools. Our results imply that it is very difficult, if not impossible, to meaningfully compare previously published measures of cell migration since previous results have been obtained using different image analysis techniques and the details of these techniques are not always reported. Using a mathematical model, we provide a physical interpretation of our edge detection results. The physical interpretation is important since edge detection algorithms alone do not specify any physical measure, or physical definition, of the leading edge of the spreading population. Our modeling indicates that variations in the image threshold parameter correspond to a consistent variation in the local cell density. This means that varying the threshold parameter is equivalent to varying the location of the leading edge in the range of approximately 1–5% of the maximum cell density

Molecular basis of binding and stability of curcumin in diamide-linked y-cyclodextrin dimers

Curcumin is a naturally occurring molecule with medicinal properties that is unstable in water, whose efficacy as a drug can potentially be enhanced by encapsulation inside a host molecule. In this work, the thermodynamics and mechanism of binding of curcumin to succinamide- and urea-linked γ-cyclodextrin (γ-CD) dimers in water are investigated by molecular dynamics simulations. The simulated binding constants of curcumin to succinamide- and urea-linked γ-CD dimers at 310 K are 11.3 × 10⁶ M ⁻¹ and 1.6 × 10⁶ M ⁻¹, respectively, matching well with previous experimental results of 8.7 × 10⁶ M ⁻¹ and 2.0 × 10⁶ M ⁻¹. The simulations reveal structural information about the encapsulation of curcumin inside the diamide-linked γ-CD dimers, with distinct qualitative differences observed for the two dimers. In particular, (1) the predominant orientation of curcumin inside the urea-linked γ-CD dimer is perpendicular to that in the succinamide-linked γ-CD dimer; (2) the magnitude of the angle between the planes of the cyclodextrins is larger for the succinamide-linked γ-CD dimer; and (3) curcumin exhibits greater configurational freedom inside the urea-linked γ-CD dimer. A consequence of some of these structural differences is that the dimer interior is more accessible to water in the succinamide-linked γ-CD dimer. These observations explain the higher stability and lower binding constant observed experimentally for curcumin in the urea-linked cyclodextrin γ-CD dimer compared with the succinamide-linked γ-CD dimer. More generally, the results demonstrate how stability and binding strength can be decoupled and thus separately optimized in host–guest systems used for drug delivery.Samuel J. Wallace, Tak W. Kee, and David M. Huan