Water-assisted laser desorption/ionization mass spectrometry for minimally invasive in vivo and real-time surface analysis using SpiderMass

Rapid, sensitive, precise and accurate analysis of samples in their native in vivo environment is critical to better decipher physiological and physiopathological mechanisms. SpiderMass is an ambient mass spectrometry (MS) system designed for mobile in vivo and real-time surface analyses of biological tissues. The system uses a fibered laser, which is tuned to excite the most intense vibrational band of water, resulting in a process termed water-assisted laser desorption/ionization (WALDI). The water molecules act as an endogenous matrix in a matrix-assisted laser desorption ionization (MALDI)-like scenario, leading to the desorption/ionization of biomolecules (lipids, metabolites and proteins). The ejected material is transferred to the mass spectrometer through an atmospheric interface and a transfer line that is several meters long. Here, we formulate a three-stage procedure that includes (i) a laser system setup coupled to a Waters Q-TOF or Thermo Fisher Q Exactive mass analyzer, (ii) analysis of specimens and (iii) data processing. We also describe the optimal setup for the analysis of cell cultures, fresh-frozen tissue sections and in vivo experiments on skin. With proper optimization, the system can be used for a variety of different targets and applications. The entire procedure takes 1–2 d for complex samples

Pathological and Test Cases For Reeb Analysis

After two decades in computational topology, it is clearly a computationally challenging area. Not only do we have the usual algorithmic and programming difficulties with establishing correctness, we also have a class of problems that are mathematically complex and notationally fragile. Effective development and deployment therefore requires an additional step - construction or selection of suitable test cases. Since we cannot test all possible inputs, our selection of test cases expresses our understanding of the task and of the problems involved. Moreover, the scale of the data sets we work with is such that, no matter how unlikely the behaviour mathematically, it is nearly guaranteed to occur at scale in every run. The test cases we choose are therefore tightly coupled with mathematically pathological cases, and need to be developed using the skills expressed most obviously in the constructing mathematical counterexamples. This paper is therefore a first attempt at reporting, classifying and analysing test cases previously used in computational topology, and the expression of a philosophy of how to test topological code

Une nouvelle voie d'abord pour la neurolyse endoscopique du nerf suprascapulaire à l'incisure spinoglénoïdale : étude cadavérique préliminaire

International audienceThe suprascapular nerve (SSN) can become compressed at its 2 scapular attachments: the suprascapular and the spinoglenoid notch. The objective of this study was to describe a new arthroscopic approach for SSN neurolysis at the spinoglenoid notch. Ten cadaver shoulders were used. Two were dissected to simulate the “classical” arthroscopic approach and to help in the creation of a new “direct medial retrospinal” approach. Eight other shoulders were used to validate this new approach, with control of the whole juxta-glenoid course of the SSN as criterion of success. The retrospinal posterior approach allowed the entire juxta-glenoid segment of the SSN to be explored in 6 cases out of 8. One exploration was incomplete, another not feasible. SSN neurolysis at the spinoglenoid notch was feasible in cadavers on a retrospinal approach. © 2017 Elsevier Masson SASIntroduction Le nerf suprascapulaire (NSS) peut être comprimé à ses 2 points de fixation scapulaire : incisure suprascapulaire et incisure spinoglénoïdale (ISG). L’objectif de ce travail est de décrire un nouvel abord endoscopique pour la neurolyse du NSS à l’ISG.Méthode Dix épaules ont été utilisées. Deux épaules ont été disséquées pour simuler le trajet des voies d’abord endoscopiques « classiques » et aider à la création d’une nouvelle voie dite « médiale rétrospinale directe ». Huit autres épaules ont permis de valider cette nouvelle voie avec comme critère de réussite le contrôle de la totalité du trajet juxtaglénoïdien du NSS.Résultats La voie postérieure rétrospinale a permis d’explorer tout le segment juxtaglénoïdien du NSS dans 6 cas sur 8. Une exploration a été incomplète, une autre non réalisable.Conclusion La neurolyse du NSS à l’ISG est possible sur cadavre par l’utilisation d’une voie rétrospinale

Topology Verification for Isosurface Extraction

The broad goals of verifiable visualization rely on correct algorithmic implementations. We extend a framework for verification of isosurfacing implementations to check topological properties. Specifically, we use stratified Morse theory and digital topology to design algorithms which verify topological invariants. Our extended framework reveals unexpected behavior and coding mistakes in popular publicly available isosurface codes

Learning from Failure – An Important Step in Innovation

There is a reluctance to publish “negative” data in many fields. However, there is so much to be learned from what did not work! Failure can be an important step in innovation. Health professional educators around the world strive to deliver effective SP-based interventions for their learners by leveraging on the strengths and opportunities whilst mitigating any challenges they face in their local context. The pandemic has created unprecedented pressure to “try something new” as we navigate the prevailing safe management measures and restrictions imposed at various levels (government, organizational, personal preference). Whilst many adaptations result in effective interventions, sometimes we learn more from the innovations that did not go quite as planned. The ability to see failure as a stepping-stone to success is a quality we should celebrate. The Association of SP Educators (ASPE) International Committee is charged with building member networks, identifying cultural differences in context and approach to SP simulation, and outlining needs of international SP programs. In this spirit, SP educators from the ASPE International Committee, representing several countries, will present examples of times they learned a great deal through trial and error. They will offer suggestions for adaptations of SP practice and describe lessons learned with reference to the ASPE Standards of Best Practice and with particular emphasis on ethical components, including safe work practices. Workshop Objectives Describe ways in which the COVID-19 pandemic has been a driver for change Explore examples of innovations and adaptations to practice Reflect on the value of failure as a steppingstone in innovation Planned Format Through a series of micro presentations interspersed with large and small group discussions, we will hear examples of lessons learned through innovation during a time of unprecedented change

Anisotropic Rectangular Metric For Polygonal Surface Remeshing

We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangleshaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity