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Non-invasive Measurement of Vitreous Humor Stiffness in the Mouse using MR Elastography
19 June 2023
In vivo, non-invasive measurements of the stiffness (elastic modulus) of biological tissue can be performed with magnetic resonance elastography (MRE). Many studies have illustrated the versatility of MRE; stiffness estimates have been obtained from liver, muscle, breast, brain and heart. Tissue health or disease is often indicated by its stiffness. In many cases tissue health is determined through invasive biopsy, which can subject the patient to discomfort and various risks. Non-invasive procedures, such as palpation, are qualitative, suffer from patient-to-patient variability, and are impossible in deep tissue. Furthermore, these measurements often only provide results in localized regions. However, with the continued development of MRE equipment and protocols, regional non-invasive measures of stiffness are becoming feasible in most soft tissues. In this study we demonstrate the measurement of loss and storage modulus of vitreous humor of the mouse eye using MR elastography non-invasively, in vivo.
OPTITEC is a shining light of French photonics
19 June 2023
The south of France is home to a thriving optics and photonocs community. Belle Dumé talks to key players to find out the benefits of living and working in the land of light.
Pale Active Helicoptere APA air cosmos
19 June 2023
Onera is participating in all-out research to make helicopters quieter. Objective: noise 8 dB lower than ICAO standards.
MRI compliant micro-motors for medical and biomedical applications
19 June 2023
The performances offered by Magnetics Resonance Imaging (MRI) are widely recognized and used by practitioners. Mainly used for diagnostic issues, MRI becomes more and more an interventional tool in image-assisted classic or robotic surgery. However, constraints imposed by the MRI strong magnetic field and strong magnetic gradients in terms of material and architecture are often obstacles to MRI guided robotics. Designers have to deal with the few choices offered to them to build a robot which will be able to respond to severe specifications, in terms of space limitations, magnetic field sensitivity and image impact. Piezoelectric micro-motors are good candidates to fulfil these requirements in several fields of applications.
MSPA motors for rotary motions
19 June 2023
Modular Stepping Piezoelectric Actuators (MSPA) are inertial motors working under the stick-slip principle [1].
The advantages of rotary MSPA are unlimited stroke, torque at rest, high resolution, nonmagnetic and vacuum compatibility.
This paper presents the new MSPA developments regarding rotary motion at Cedrat Technologies for macro and
micro sizes MSPA. These progresses follow the previous technical investigations around noise reduction, miniaturization
at low voltage and the integration of MSPA modules [2]. In this paper two rotary piezo motors are presented: The first
one is a macro size MSPA based on APA40SM. It is developed to work under nuclear environment: operational temperature
up to 70 degrees, vacuum, 5 Tesla magnetic field and high radiation fields (3,5 kGy/hour gamma radiation power
and 500 Mn/(cm².second) neutron radiation power). The second is a micro size MSPA based on APA30uXS. This motor
is used for embedded application such as nonmagnetic shutter.
Nanometric linear piezo-actuator with integrated Strain Gages for high stability positioning
19 June 2023
Many applications require a mechanism capable of nanometric resolution position tuning, and with the ability to maintain perfectly this position for a long time (more than several days). For those applications, piezo-actuators are a perfect fit since they easily provide nanometric resolution. However, they require the use of a position sensor to be able to maintain stable position over time. Until now, the long-term stability of strain gages (SG) for position measurement was questionable. Using its extensive know-how of strain gages integration and new instrumentation equipment, Cedrat Technologies has managed to demonstrate the ability of a piezo-mechanism with integrated strain gages sensors to achieve nanometric position stability. This technology opens new possibilities for industrial, aeronautical, and space applications.
