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  1. Free, publicly-accessible full text available April 1, 2023
  2. Free, publicly-accessible full text available December 20, 2022
  3. Stephanidis C., Antona M. (Ed.)
    The objective of this study is to develop and use a virtual reality game as a tool to assess the effects of realistic stress on the behavioral and physiological responses of participants. The game is based on a popular Steam game called Keep Talking Nobody Explodes, where the players collaborate to defuse a bomb. Varying levels of difficulties in solving a puzzle and time pressures will result in different stress levels that can be measured in terms of errors, response times, and other physiological measurements. The game was developed using 3D programming tools including Blender and a virtual reality developmentmore »kit (VRTK). To measure response times accurately, we added LSL (Lab Stream Layer) Markers to collect and synchronize physiological signals, behavioral data, and the timing of game events. We recorded Electrocardiogram (ECG) data during gameplay to assess heart rate and heart-rate variability (HRV) that have been shown as reliable indicators of stress. Our empirical results showed that heart rate increased significantly while HRV reduced significantly when the participants under high stress, which are consistent with the prior mainstream stress research. This VR game framework is publicly available in GitHub and allows researchers to measure and synchronize other physiological signals such as electroencephalogram, electromyogram, and pupillometry.« less
  4. Measuring the organization of the cellular cytoskeleton and the surrounding extracellular matrix (ECM) is currently of wide interest as changes in both local and global alignment can highlight alterations in cellular functions and material properties of the extracellular environment. Different approaches have been developed to quantify these structures, typically based on fiber segmentation or on matrix representation and transformation of the image, each with its own advantages and disadvantages. Here we present AFT − Alignment by Fourier Transform , a workflow to quantify the alignment of fibrillar features in microscopy images exploiting 2D Fast Fourier Transforms (FFT). Using pre-existing datasetsmore »of cell and ECM images, we demonstrate our approach and compare and contrast this workflow with two other well-known ImageJ algorithms to quantify image feature alignment. These comparisons reveal that AFT has a number of advantages due to its grid-based FFT approach. 1) Flexibility in defining the window and neighborhood sizes allows for performing a parameter search to determine an optimal length scale to carry out alignment metrics. This approach can thus easily accommodate different image resolutions and biological systems. 2) The length scale of decay in alignment can be extracted by comparing neighborhood sizes, revealing the overall distance that features remain anisotropic. 3) The approach is ambivalent to the signal source, thus making it applicable for a wide range of imaging modalities and is dependent on fewer input parameters than segmentation methods. 4) Finally, compared to segmentation methods, this algorithm is computationally inexpensive, as high-resolution images can be evaluated in less than a second on a standard desktop computer. This makes it feasible to screen numerous experimental perturbations or examine large images over long length scales. Implementation is made available in both MATLAB and Python for wider accessibility, with example datasets for single images and batch processing. Additionally, we include an approach to automatically search parameters for optimum window and neighborhood sizes, as well as to measure the decay in alignment over progressively increasing length scales.« less
    Free, publicly-accessible full text available October 14, 2022
  5. Genetic essentialism of race is the belief that racial groups have different underlying genetic essences which cause them to differ physically, cognitively, or behaviorally. Apparently no published studies have explored if belief in genetic essentialism of race among adolescents differs after many weeks of formal instruction about different domains of genetics knowledge. Nor have any studies explored if such differences reflect a coherent change in students’ racial schemas. We use a quasi-experimental design (N = 254 students in 7th-12th grade) to explore these gaps. Over the course of three months, we compared students who learned from a curriculum on multifactorialmore »inheritance and genetic ancestry to students who learned from their business as usual (BAU) genetics curriculum that discussed Mendelian and molecular genetics without any reference to race, multifactorial genetics, or genetic ancestry. Relative to the BAU condition, classrooms that learned from the multifactorial genetics and ancestry curriculum grew significantly more in their knowledge of multifactorial genetics and decreased significantly more in their genetic essentialist perceptions, attributions, and beliefs. From a conceptual change perspective, these findings suggest that classrooms using a curriculum emphasizing genetic complexity are more likely to shift toward a coherent anti-essentialist understanding of racial difference.« less
  6. Abstract We measured hardness, modulus of elasticity, and, for the first time, loss tangent, energy of fracture, abrasion resistance, and impact resistance of zinc- and manganese-enriched materials from fangs, stings and other “tools” of an ant, spider, scorpion and nereid worm. The mechanical properties of the Zn- and Mn-materials tended to cluster together between plain and biomineralized “tool” materials, with the hardness reaching, and most abrasion resistance values exceeding, those of calcified salmon teeth and crab claws. Atom probe tomography indicated that Zn was distributed homogeneously on a nanometer scale and likely bound as individual atoms to more than ¼more »of the protein residues in ant mandibular teeth. This homogeneity appears to enable sharper, more precisely sculpted “tools” than materials with biomineral inclusions do, and also eliminates interfaces with the inclusions that could be susceptible to fracture. Based on contact mechanics and simplified models, we hypothesize that, relative to plain materials, the higher elastic modulus, hardness and abrasion resistance minimize temporary or permanent tool blunting, resulting in a roughly 2/3 reduction in the force, energy, and muscle mass required to initiate puncture of stiff materials, and even greater force reductions when the cumulative effects of abrasion are considered. We suggest that the sharpness-related force reductions lead to significant energy savings, and can also enable organisms, especially smaller ones, to puncture, cut, and grasp objects that would not be accessible with plain or biomineralized “tools”.« less
    Free, publicly-accessible full text available December 1, 2022
  7. Abstract The anomalous diffusion of resonant protons in parallel and perpendicular velocity space by kinetic Alfvén waves is discussed. The velocity diffusion coefficient is calculated by employing an autocorrelation function for proton trajectories. It is found that for protons resonant with the waves, the perpendicular diffusion coefficient decays away for a sufficiently long time, but parallel diffusion monotonically increases in time until it saturates at a certain level. This result indicates that a portion of resonant protons can undergo anomalous diffusion along the background magnetic field even if the intensity of the kinetic Alfvén wave is sufficiently low. The presentmore »findings imply that under suitable conditions, astrophysical charged-particle acceleration can take place in the parallel direction.« less
  8. Abstract

    Fatty acid biosynthesis (FAB) is an essential and highly conserved metabolic pathway. In bacteria, this process is mediated by an elaborate network of protein•protein interactions (PPIs) involving a small, dynamic acyl carrier protein that interacts with dozens of other partner proteins (PPs). These PPIs have remained poorly characterized due to their dynamic and transient nature. Using a combination of solution-phase NMR spectroscopy and protein-protein docking simulations, we report a comprehensive residue-by-residue comparison of the PPIs formed during FAB inEscherichia coli. This technique describes and compares the molecular basis of six discrete binding events responsible forE. coliFAB and offers insightsmore »into a method to characterize these events and those in related carrier protein-dependent pathways.

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