Strength Assessment of Rectangular Plates Subjected to Extreme Cyclic Load Reversals

The objective of this study is to investigate the strength of the rectangular plates subjected to cyclic load reversals with varying strain ranges. The finite element solution is implemented to estimate the load-carrying capacity. The influence of the initial imperfections, plate thicknesses and aspect ratio parameters have been accounted for. The cyclic response is predicted by using the material model assumed to follow the combined non-linear isotropic and kinematic strain hardening rules with Von Misses yield criterion accounting for the Bauschinger effect. It has been shown that the type of plastic formation during the cyclic load has a significant influence on the structural capacity and stiffness reduction. The initial imperfection has a significant impact on the ultimate load capacity reduction where the uni-modal initial imperfection type leads to a more stable load transition and plastic formation, reducing the structural capacity during the cyclic load exposure

Spectral domain optical coherence tomography in mouse models of retinal degeneration

Purpose: Spectral domain optical coherence tomography (SD-OCT) allows cross-sectional visualization of retinal structures in vivo. Here, we report the efficacy of a commercially available SD-OCT device to study mouse models of retinal degeneration. Methods: C57BL/6 and BALB/c wild type mice and three different mouse models of hereditary retinal degeneration (Rho(-/-), rd1, RPE65(-/-)) were investigated using confocal scanning laser ophthalmoscopy (cSLO) for en face visualization and SD-OCT for cross-sectional imaging of retinal structures. Histology was performed to correlate structural findings in SD-OCT with light microscopic data. Results: In C57BL/6 and BALB/c mice, cSLO and SD-OCT imaging provided structural details of frequently used control animals (central retinal thickness, CRTC57BL/6 = 237+/-2microm and CRTBALB/c = 211+/-10microm). RPE65-/- mice at 11 months of age showed a significant reduction of retinal thickness (CRTRPE65 = 193+/-2microm) with thinning of the outer nuclear layer. Rho-/- mice at P28 demonstrated degenerative changes mainly in the outer retinal layers (CRTRho = 193+/-2microm). Examining rd1 animals before and after the onset of retinal degeneration allowed to monitor disease progression (CRTrd1 P11 = 246+/-4microm, CRTrd1 P28 = 143+/-4microm). Correlation of CRT assessed by histology and SD-OCT was high (r(2) = 0.897). Conclusion: We demonstrated cross sectional visualization of retinal structures in wild type mice and mouse models for retinal degeneration in vivo using a commercially available SD-OCT device. This method will help to reduce numbers of animals needed per study by allowing longitudinal study designs and facilitate characterization of disease dynamics and evaluation of putative therapeutic effects following experimental interventions

Spectral domain optical coherence tomography in mouse models of retinal degeneration.

PURPOSE: Spectral domain optical coherence tomography (SD-OCT) allows cross-sectional visualization of retinal structures in vivo. Here, the authors report the efficacy of a commercially available SD-OCT device to study mouse models of retinal degeneration. METHODS: C57BL/6 and BALB/c wild-type mice and three different mouse models of hereditary retinal degeneration (Rho(-/-), rd1, RPE65(-/-)) were investigated using confocal scanning laser ophthalmoscopy (cSLO) for en face visualization and SD-OCT for cross-sectional imaging of retinal structures. Histology was performed to correlate structural findings in SD-OCT with light microscopic data. RESULTS: In C57BL/6 and BALB/c mice, cSLO and SD-OCT imaging provided structural details of frequently used control animals (central retinal thickness, CRT(C57BL/6) = 237 +/- 2 microm and CRT(BALB/c) = 211 +/- 10 microm). RPE65(-/-) mice at 11 months of age showed a significant reduction of retinal thickness (CRT(RPE65) = 193 +/- 2 microm) with thinning of the outer nuclear layer. Rho(-/-) mice at P28 demonstrated degenerative changes mainly in the outer retinal layers (CRT(Rho) = 193 +/- 2 microm). Examining rd1 animals before and after the onset of retinal degeneration allowed monitoring of disease progression (CRT(rd1 P11) = 246 +/- 4 microm, CRT(rd1 P28) = 143 +/- 4 microm). Correlation of CRT assessed by histology and SD-OCT was high (r(2) = 0.897). CONCLUSIONS: The authors demonstrated cross-sectional visualization of retinal structures in wild-type mice and mouse models for retinal degeneration in vivo using a commercially available SD-OCT device. This method will help to reduce numbers of animals needed per study by allowing longitudinal study designs and will facilitate characterization of disease dynamics and evaluation of putative therapeutic effects after experimental interventions

COVID-19 Among Patients With Inflammatory Rheumatic Diseases

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