Tracking Cortical Surface Deformation Using Stereovision

We present a rapid-prototyping process to fabricate aspherical lens arrays based on surface deformation due to thermal expansion of PDMS. Using laser-structuring and molding in combination with an FEM-based shape optimization, we were able to design, fabricate and characterize different micro-lens arrays. This fabrication process can be used for almost any kind of arbitrary lens shape, which allows for a large design freedom for micro lenses.

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A Simple Method to Avoid Brain Shift during Neuronavigation: Technical Note

Arquivos Brasileiros de Neurocirurgia Brazilian Neurosurgery ◽

10.1055/s-0040-1716560 ◽

2020 ◽

Author(s):

Jair Leopoldo Raso

Keyword(s):

Dura Mater ◽

Brain Area ◽

Conventional Technique ◽

Technical Note ◽

Cortical Surface ◽

Brain Shift ◽

Simple Method ◽

Cortex Area ◽

Neuronavigation System ◽

The Brain

Abstract Introduction The precise identification of anatomical structures and lesions in the brain is the main objective of neuronavigation systems. Brain shift, displacement of the brain after opening the cisterns and draining cerebrospinal fluid, is one of the limitations of such systems. Objective To describe a simple method to avoid brain shift in craniotomies for subcortical lesions. Method We used the surgical technique hereby described in five patients with subcortical neoplasms. We performed the neuronavigation-guided craniotomies with the conventional technique. After opening the dura and exposing the cortical surface, we placed two or three arachnoid anchoring sutures to the dura mater, close to the edges of the exposed cortical surface. We placed these anchoring sutures under microscopy, using a 6–0 mononylon wire. With this technique, the cortex surface was kept close to the dura mater, minimizing its displacement during the approach to the subcortical lesion. In these five cases we operated, the cortical surface remained close to the dura, anchored by the arachnoid sutures. All the lesions were located with a good correlation between the handpiece tip inserted in the desired brain area and the display on the navigation system. Conclusion Arachnoid anchoring sutures to the dura mater on the edges of the cortex area exposed by craniotomy constitute a simple method to minimize brain displacement (brain-shift) in craniotomies for subcortical injuries, optimizing the use of the neuronavigation system.

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Analysis of surface deformation and driving forces in Lanzhou

Open Geosciences ◽

10.1515/geo-2020-0128 ◽

2020 ◽

Vol 12 (1) ◽

pp. 1127-1145

Author(s):

Wenhui Wang ◽

Yi He ◽

Lifeng Zhang ◽

Youdong Chen ◽

Lisha Qiu ◽

...

Keyword(s):

International Development ◽

Surface Deformation ◽

Driving Forces ◽

Influence Factors ◽

Chinese Government ◽

Single Factor ◽

Rapid Urbanization ◽

Temporal Characteristics ◽

Maximum Deformation ◽

Rate Of Increase

AbstractSurface deformation has become an important factor affecting urban development. Lanzhou is an important location in the Belt and Road Initiative, an international development policy implemented by the Chinese government. Because of rapid urbanization in Lanzhou, surface deformation occurs easily. However, the spatial-temporal characteristics of surface deformation and the interaction of driving forces behind surface deformation in Lanzhou are unclear. This paper uses small baseline subset InSAR (SBAS-InSAR) technology to obtain the spatial-temporal characteristics of surface deformation in Lanzhou based on 32 Sentinel-1A data from March 2015 to January 2017. We further employ a geographical detector (geo-detector) to analyze the driving forces (single-factor effects and multifactor interactions) of surface deformation. The results show that the central urban area of Lanzhou was stable, while there was surface deformation around Nanhuan road, Dongfanghong Square, Jiuzhou, Country Garden, Dachaiping, Yujiaping, Lanzhou North Freight Yard, and Liuquan Town. The maximum deformation rate was −26.50 mm year−1, and the maximum rate of increase was 9.80 mm year−1. The influence factors of surface deformation in Lanzhou was a complex superposition relationship among various influencing factors, not a result of the single factor. The interaction between the built-up area and land cover types was the most important factor behind surface deformation in Lanzhou. This paper provides the reference data and scientific foundation for disaster prevention in Lanzhou.

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