gaussian mixture model (gmm)  (MathWorks Inc)

Journal: Nmr in Biomedicine

Article Title: Cluster Analysis of VERDICT MRI for Cancer Tissue Characterization in Neuroendocrine Tumors

doi: 10.1002/nbm.70050

Figure Lengend Snippet: Scatterplot of R against f IC for all tumor voxels ( n = 11,519) and subjects (A; left side). The black contours show the 2D Gaussian mixture model (GMM) fit with each voxel data point color‐coded based on the probability of belonging to each component (blue, green, and red). Contours of the three individual GMM components are shown as smaller plots (right side). R and f IC maps of tumor ROIs were used to generate color‐coded posterior probability maps of each GMM component (B; Subject 6 shown as example).

Article Snippet: A 2D Gaussian mixture model (GMM) was then fitted to the f IC and R values of all tumor voxels using an algorithm based on the MATLAB function fitgmdist with 20 random initializations to avoid local optima and a regularization value of 3.5 × 10 −3 to avoid overfitting ( mathworks.com/matlabcentral/fileexchange/71496‐identification‐of‐subregions‐in‐parameter‐maps‐by‐gmm ) [ ].

Techniques:

Journal: Nmr in Biomedicine

Article Title: Cluster Analysis of VERDICT MRI for Cancer Tissue Characterization in Neuroendocrine Tumors

doi: 10.1002/nbm.70050

Figure Lengend Snippet: Model fit output of the Gaussian mixture model (GMM) of three clusters fitted to R and f IC for all tumor voxels. The table shows cluster ID as defined by histological analysis (Figures 4 and 6 ), mean values of R and f IC ( μ ) for each cluster, and the cluster fraction indicating the percentage of tumor voxel data that is associated with each Gaussian component.

Article Snippet: A 2D Gaussian mixture model (GMM) was then fitted to the f IC and R values of all tumor voxels using an algorithm based on the MATLAB function fitgmdist with 20 random initializations to avoid local optima and a regularization value of 3.5 × 10 −3 to avoid overfitting ( mathworks.com/matlabcentral/fileexchange/71496‐identification‐of‐subregions‐in‐parameter‐maps‐by‐gmm ) [ ].

Techniques:

Journal: Nmr in Biomedicine

Article Title: Cluster Analysis of VERDICT MRI for Cancer Tissue Characterization in Neuroendocrine Tumors

doi: 10.1002/nbm.70050

Figure Lengend Snippet: Gaussian mixture model (GMM) probability maps from the VERDICT cluster analysis of R and f IC (left columns) and classification maps from the histology analysis (right columns). The colors in the histology classification maps represent different tissue types: necrotic (red), fibrotic (blue), and viable cancer cells (green). Black pixels indicate areas where no stain was present. The colors in the VERDICT cluster maps represent the probability of each voxel belonging to the GMM clusters, with colors chosen for each cluster to best match with the histology maps.

Article Snippet: A 2D Gaussian mixture model (GMM) was then fitted to the f IC and R values of all tumor voxels using an algorithm based on the MATLAB function fitgmdist with 20 random initializations to avoid local optima and a regularization value of 3.5 × 10 −3 to avoid overfitting ( mathworks.com/matlabcentral/fileexchange/71496‐identification‐of‐subregions‐in‐parameter‐maps‐by‐gmm ) [ ].

Techniques: Staining

Journal: Cell reports

Article Title: Molecular basis for the increased fusion activity of the Ebola virus glycoprotein epidemic variant A82V: Insights from simulations and experiments

doi: 10.1016/j.celrep.2025.115521

Figure Lengend Snippet: (A) Schematic of the smFRET assay in which pseudovirions formed with the HIV-1 core are immobilized to enable imaging with TIRF microscopy. (B) A GP CL monomer with the sites of fluorophore attachment indicated (donor, green; acceptor, red. PDB: 5JQ3 with glycan cap removed to reflect GP CL ). (C) Example smFRET trajectories from individual GP CL trimers on pseudovirions with A82 (top) or V82 (bottom) GP CL . The experimental trajectories are shown in blue, overlaid with the idealized trajectory resulting from fitting to the 5-state HMM (red). The prefusion conformation is indicated with a gray bar, along with the observed intermediate conformations. (D) FRET histograms for A82 GP CL smFRET trajectories acquired under the indicated conditions. Histograms reflect the average of three independent groups of trajectories; error bars represent the standard error. Overlaid on the histograms are four Gaussian distributions (gray) for the four non-zero FRET states, with means determined through HMM analysis of the individual smFRET trajectories. The sum of the Gaussians is highlighted by the red line. The 0.8-FRET prefusion conformation and the 0.05-FRET state are indicated. The 0-FRET state has been removed from the histograms to facilitate visualization of the 0.05-FRET state. N indicates the number of smFRET trajectories used to compile each histogram. (E) FRET histograms for V82 GP CL as in (D). (F) Violin plots displaying the occupancy distribution in the 0.8-FRET prefusion conformation for each GP CL population imaged under the given conditions. Horizontal lines indicate the population mean occupancies; the gray circles and whiskers indicate the medians and quantiles, respectively. p values were determined by one-way ANOVA and multiple comparison test (ns, p > 0.05). (G) Violin plots displaying the occupancy distribution in the 0.05-FRET state, displayed as in (F). Numeric data are presented in . (H and I) Histograms of dwell times in the 0.8-FRET prefusion conformation extracted from the HMM analysis of smFRET trajectories (blue circles) acquired for (H) A82 and (I) V82 GP CL , under the indicated conditions. Histograms are displayed with logarithmically spaced bins to assist in visualization of the two time constants. Histograms were fit to double exponential functions A fast e x p t / t fast + A slow e x p t / t slow , where A fast and A slow are amplitudes, and t fast and t slow are the corresponding time constants. Double exponential fits are overlaid in solid red lines with the individual exponentials in dashed red lines. The two time constants are indicated with 95% confidence intervals in parentheses. (J) The amplitudes, A fast and A slow , determined in the exponential fitting in (A) and (B). Bars reflect the fitted values with error bars indicating the 95% confidence intervals. p values are indicated (ns, p > 0.05), determined by one-way ANOVA and multiple comparison test.

Article Snippet: Projection of the simulations into the eigenspace formed by the first three principal components and subsequent clustering using Gaussian mixture models was performed in Matlab.

Techniques: Smfret Assay, Imaging, Microscopy, Glycoproteomics, Comparison