581 research outputs found
Decoupling Strain and Ligand Effects in Ternary Nanoparticles for Improved ORR Electrocatalysis
Ternary Pt–Au–M (M = 3d transition metal) nanoparticles show reduced OH adsorption energies and improved activity for the oxygen reduction reaction (ORR) compared to pure Pt nanoparticles, as obtained by density functional theory.</p
Anomalous cell sorting behavior in mixed monolayers discloses hidden system complexities
In tissue development, wound healing and aberrant cancer progression cell–cell interactions drive
mixing and segregation of cellular composites. However, the exact nature of these interactions is
unsettled. Here we study the dynamics of packed, heterogeneous cellular systems using wound
closure experiments. In contrast to previous cell sorting experiments, we find non-universal
sorting behavior. For example, monolayer tissue composites with two distinct cell types that show
low and high neighbor exchange rates (i.e., MCF-10A & MDA-MB-231) produce segregated
domains of each cell type, contrary to conventional expectation that the construct should stay
jammed in its initial configuration. On the other hand, tissue compounds where both cell types
exhibit high neighbor exchange rates (i.e., MDA-MB-231 & MDA-MB-436) produce highly mixed
arrangements despite their differences in intercellular adhesion strength. The anomalies allude to a
complex multi-parameter space underlying these sorting dynamics, which remains elusive in
simpler systems and theories merely focusing on bulk properties. Using cell tracking data, velocity
profiles, neighborhood volatility, and computational modeling, we classify asymmetric interfacial
dynamics. We indicate certain understudied facets, such as the effects of cell death & division,
mechanical hindrance, active nematic behavior, and laminar & turbulent flow as their potential
drivers. Our findings suggest that further analysis and an update of theoretical models, to capture
the diverse range of active boundary dynamics which potentially influence self-organization, is
warranted
Normal and abnormal tissue identification system and method for medical images such as digital mammograms
A system and method for analyzing a medical image to determine whether an abnormality is present, for example, in digital mammograms, includes the application of a wavelet expansion to a raw image to obtain subspace images of varying resolution. At least one subspace image is selected that has a resolution commensurate with a desired predetermined detection resolution range. A functional form of a probability distribution function is determined for each selected subspace image, and an optimal statistical normal image region test is determined for each selected subspace image. A threshold level for the probability distribution function is established from the optimal statistical normal image region test for each selected subspace image. A region size comprising at least one sector is defined, and an output image is created that includes a combination of all regions for each selected subspace image. Each region has a first value when the region intensity level is above the threshold and a second value when the region intensity level is below the threshold. This permits the localization of a potential abnormality within the image
Duchenne de boulogne: Electrodiagnosis of poliomyelitis
Duchenne de Boulogne was among the first to investigate neuromuscular diseases. He stimulated muscle and nerve with moistened surface electrodes, thereby avoiding tissue necrosis. Technique and self-designed equipment are discussed in his first major work de I'electrisation localisee . During his 30 years of practice, he examined several hundred patients with poliomyelitis. With electrodiagnostic evaluation, he focused on “electrocontractility,” the intensity of muscle contraction elicited by electrical stimulation. Based on his electrophysiologic findings, Duchenne suggested that the responsible lesion resided within the spinal cord. He used electrical stimulation for treatment and recognized prognostic features.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50146/1/880130111_ftp.pd
Normal epithelial and triple-negative breast cancer cells show the same invasion potential in rigid spatial confinement
The extra-cellular microenvironment has a fundamental role in tumor growth and progression,
strongly affecting the migration strategies adopted by single cancer cells during metastatic invasion. In
this study, we use a novel microfluidic device to investigate the ability of mesenchymal and epithelial
breast tumor cells to fluidize and migrate through narrowing microstructures upon chemoattractant
stimulation. We compare the migration behavior of two mesenchymal breast cancer cell lines and one
epithelial cell line, and find that the epithelial cells are able to migrate through the narrowest
microconstrictions as the more invasive mesenchymal cells. In addition, we demonstrate that
migration of epithelial cells through a highly compressive environment can occur in absence of a
chemoattractive stimulus, thus evidencing that they are just as prone to react to mechanical cues as
invasive cell
Normal volumes and microstructural integrity of deep gray matter structures in AQP4+ NMOSD
OBJECTIVE: To assess volumes and microstructural integrity of deep gray matter structures in a homogeneous cohort of patients with neuromyelitis optica spectrum disorder (NMOSD). METHODS: This was a cross-sectional study including 36 aquaporin-4 antibody-positive (AQP4 Ab-positive) Caucasian patients with NMOSD and healthy controls matched for age, sex, and education. Volumetry of deep gray matter structures (DGM; thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, nucleus accumbens) was performed using 2 independent automated methods. Microstructural integrity was assessed based on diffusion tensor imaging. RESULTS: Both volumetric analysis methods consistently revealed similar volumes of DGM structures in patients and controls without significant group differences. Moreover, no differences in DGM microstructural integrity were observed between groups. CONCLUSIONS: Deep gray matter structures are not affected in AQP4 Ab-positive Caucasian patients with NMOSD. NMOSD imaging studies should be interpreted with respect to Ab status, educational background, and ethnicity of included patients
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