Ambient Mass Spectrometry Imaging by Water-Assisted Laser Desorption/Ionization for Ex Vivo and in Vivo Applications.

Water-assisted laser desorption/ionization mass spectrometry (WALDI-MS), also known as SpiderMass, is an emerging ambient ionization technique for in vivo and real-time analysis. It employs a remote infrared (IR) laser tuned to excite the most intense vibrational band (O-H) of water. The water molecules act as an endogenous matrix leading to the desorption/ionization of a variety of biomolecules from tissues, particularly metabolites and lipids. WALDI-MS was recently advanced into an imaging modality for ex vivo 2D sections and 3D in vivo real-time imaging. Here, we describe the methodological aspects for performing 2D and 3D imaging experiments with WALDI-MSI and the parameters for optimizing the image acquisition.

Robot-Assisted SpiderMass for In Vivo Real-Time Topography Mass Spectrometry Imaging.

Mass spectrometry imaging (MSI) has shown to bring invaluable information for biological and clinical applications. However, conventional MSI is generally performed ex vivo from tissue sections. Here, we developed a novel MS-based method for in vivo mass spectrometry imaging. By coupling the SpiderMass technology, that provides in vivo minimally invasive analysis-to a robotic arm of high accuracy, we demonstrate that images can be acquired from any surface by moving the laser probe above the surface. By equipping the robotic arm with a sensor, we are also able to both get the topography image of the sample surface and the molecular distribution, and then and plot back the molecular data, directly to the 3D topographical image without the need for image fusion. This is shown for the first time with the 3D topographic MS-based whole-body imaging of a mouse. Enabling fast in vivo MSI bridged to topography paves the way for surgical applications to excision margins.

Finite Element Method-Based Kinematics and Closed-Loop Control of Soft, Continuum Manipulators.

This article presents a modeling methodology and experimental validation for soft manipulators to obtain forward kinematic model (FKM) and inverse kinematic model (IKM) under quasi-static conditions (in the literature, these manipulators are usually classified as continuum robots. However, their main characteristic of interest in this article is that they create motion by deformation, as opposed to the classical use of articulations). It offers a way to obtain the kinematic characteristics of this type of soft robots that is suitable for offline path planning and position control. The modeling methodology presented relies on continuum mechanics, which does not provide analytic solutions in the general case. Our approach proposes a real-time numerical integration strategy based on finite element method with a numerical optimization based on Lagrange multipliers to obtain FKM and IKM. To reduce the dimension of the problem, at each step, a projection of the model to the constraint space (gathering actuators, sensors, and end-effector) is performed to obtain the smallest number possible of mathematical equations to be solved. This methodology is applied to obtain the kinematics of two different manipulators with complex structural geometry. An experimental comparison is also performed in one of the robots, between two other geometric approaches and the approach that is showcased in this article. A closed-loop controller based on a state estimator is proposed. The controller is experimentally validated and its robustness is evaluated using Lypunov stability method.

Discrete Takagi-Sugeno's fuzzy models: reduction of the number of LMI in fuzzy control techniques.

Conditions about the stabilization of Takagi-Sugeno fuzzy models can systematically be derived and solved usually using linear matrix inequality problems. Current research tries to lower any pessimism. However, often it leads to an important increase in the number of decision variables, and problems become unsolvable. In this correspondence, we choose to reduce the number of decision variables while not raising the conservatism in comparison with previous results. This correspondence deals with the discrete case, which is harder to solve. We supply results about the stabilization, the regulator problem, and also H( infinity) control.