Direct Seamless Parametrization

2021 ◽  
Vol 40 (1) ◽  
pp. 1-14
Author(s):  
Zohar Levi
Keyword(s):  
Small Patch ◽  
Good Estimator ◽  
Local Estimation ◽  
Anisotropic Scaling ◽  
Separate Step ◽  
Feature Alignment

We present a method for seamless surface parametrization. Recent popular methods first generate a cross-field, where curvature is concentrated at singular vertices. Next, in a separate step, the surface is laid out in the domain subject to derived seamlessness constraints. This decoupling of the process into two independent problems, each with its own objective, leads to suboptimal results. In contrast, our method solves both problems together using domain variables. The key ingredient to the robustness of our method is a rounding strategy based on local estimation. The insight is that testing a small patch to decide between two likely possibilities is a good estimator. Most distortion measures can be used with our method, which get minimized consistently throughout the pipeline. Our method also enables feature alignment, as well as alignment to principle curvatures, and isotropic and anisotropic scaling.

High-voltage electron microscopy of patch-clamped membranes

1987 ◽  
Vol 45 ◽  
pp. 582-583
Author(s):  
F. Sachs ◽  
M. J. Song
Keyword(s):  
Electron Microscopy ◽  
Cell Membrane ◽  
Patch Clamp ◽  
High Voltage Electron Microscopy ◽  
Small Patch ◽  
Cellular Electrophysiology ◽  
Voltage Electron ◽  
Electron Microscopes ◽  
Patch Technique ◽  
Membrane Patch

Cellular electrophysiology has been revolutionized by the introduction of patch clamp techniques. The patch clamp records current from a small patch of the cell membrane which has been sucked into a glass pipette. The membrane patch, a few micons in diameter, is attached to the glass by a seal which is electrically, diffusionally and mechanically tight. Because of the tight electrical seal, the noise level is low enough to record the activity of single ion channels over a time scale extending from 10μs to days. However, although the patch technique is over ten years old, the patch structure is unknown. The patch is inside a glass pipette where it has been impossible to see with standard electron microscopes. We show here that at 1 Mev the glass pipette is transparent and the membrane within can be seen with a resolution of about 30 A.

VIII.—Note on the Martley Quartzite

1898 ◽  
Vol 5 (12) ◽  
pp. 562-564 ◽  
Author(s):  
Theodore Groom
Keyword(s):  
Small Patch

My attention has been drawn to a recent notice' by Mr. Colesof a quartzite at Martley. Since this area is included withinthe district of the Malvern and Abberley Hills, which I have beenengaged in studying for more than two years, a brief descriptionof the relations of the rocks, as determined by myself in Januaryof the present year, may not be out of place. The small patch of interesting rocks here is likely to become covered up as cultivation progresses; indeed, the exposure is evidently much less extensive than it was when Phillips described it in his memoir on the Malvern and Abberley Hills. Mr. Coles has, moreover, I think, hardly done justice to the remarkable section exposed here.

scholarly journals Development, characterization, and applications of multi-material stereolithography bioprinting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bagrat Grigoryan ◽  
Daniel W. Sazer ◽  
Amanda Avila ◽  
Jacob L. Albritton ◽  
Aparna Padhye ◽  
...  
Keyword(s):  
Material Selection ◽  
Cell Types ◽  
Fluorescent Tracers ◽  
Regional Feature ◽  
Multicellular Aggregates ◽  
Distinct Cell ◽  
Adenocarcinoma Cells ◽  
Mammalian Tissues ◽  
Heterotypic Interactions ◽  
Feature Alignment

AbstractAs a 3D bioprinting technique, hydrogel stereolithography has historically been limited in its ability to capture the spatial heterogeneity that permeates mammalian tissues and dictates structure–function relationships. This limitation stems directly from the difficulty of preventing unwanted material mixing when switching between different liquid bioinks. Accordingly, we present the development, characterization, and application of a multi-material stereolithography bioprinter that provides controlled material selection, yields precise regional feature alignment, and minimizes bioink mixing. Fluorescent tracers were first used to highlight the broad design freedoms afforded by this fabrication strategy, complemented by morphometric image analysis to validate architectural fidelity. To evaluate the bioactivity of printed gels, 344SQ lung adenocarcinoma cells were printed in a 3D core/shell architecture. These cells exhibited native phenotypic behavior as evidenced by apparent proliferation and formation of spherical multicellular aggregates. Cells were also printed as pre-formed multicellular aggregates, which appropriately developed invasive protrusions in response to hTGF-β1. Finally, we constructed a simplified model of intratumoral heterogeneity with two separate sub-populations of 344SQ cells, which together grew over 14 days to form a dense regional interface. Together, these studies highlight the potential of multi-material stereolithography to probe heterotypic interactions between distinct cell types in tissue-specific microenvironments.

Robust Feature Learning for Adversarial Defense via Hierarchical Feature Alignment

2020 ◽  
Author(s):  
Xiaoqin Zhang ◽  
Jinxin Wang ◽  
Tao Wang ◽  
Runhua Jiang ◽  
Jiawei Xu ◽  
...  
Keyword(s):  
Feature Learning ◽  
Feature Alignment
Sign in / Sign up

Export Citation Format

Share Document