•A magnetic field sensor based on Fe-Ga alloy and Fiber Bragg Grating is developed.•The demagnetizing field is investigated and exploited to widen the detection range.•Full quadrant field detection ...is achieved by a permanent magnet bias system.•A prototype has been realized by a 3D printing technology.•The approach is suitable for field sensing based on other multifunctional materials.
A magnetic field sensor prototype is developed and tested in this work. The device exploits a Galfenol rod, i.e. a giant magnetostrictive Iron-Gallium alloy, integrated with a Fiber Bragg Grating. In particular, the full-scale range of the sensor can be modulated through the exploitation of the geometrically dependent effect of the demagnetizing field. Indeed, it pushes toward higher fields the magnetic saturation by producing a sort of magnetic shield in the material. As a consequence, the geometrical viewpoint is included into the frame of the entire design process, with the aim of investigate how it influences the detectability range and the performance of the sensor. Furthermore, a permanent magnet system providing a DC bias magnetic field has been designed and exploited to allow the device to be able to measure both negative and positive magnetic fields.
Laser-induced interstitial thermotherapy (LITT) has been recently applied to pancreas in animal models for ablation purpose. Assessment of thermal effects due to the laser-pancreatic tissue ...interaction is a critical factor in validating the procedure feasibility and safety. A mathematical model based on bioheat equation and its experimental assessment was developed. The LITT procedure was performed on 40 ex vivo porcine pancreases, with an Nd:YAG (1064 nm) energy of 1000 J and power from 1.5 up to 10 W conveyed by a quartz optical fiber with 300 μm diameter. Six fiber Bragg grating sensors have been utilized to measure temperature distribution as a function of time at fixed distances from the applicator tip within pancreas undergoing LITT. Simulations and experiments show temperature variations Δ T steeply decreasing with distance from the applicator at higher power values: at 6 W, Δ T >; 40°C at 5 mm and Δ T ≅ 5°C at 10 mm. Δ T nonlinearly increases with power close to the applicator. Ablated and coagulated tissue volumes have also been measured and experimental results agree with theoretical ones. Despite the absence of data in the current literature on pancreas optical parameters, the model allowed a quite good prediction of thermal effects. The prediction of LITT effects on pancreas is necessary to assess laser dosimetry.
Fiber Bragg gratings (FBGs) are known for their uses in applications ranging from civil engineering to medicine. A bare FBG is small and light; hence, it can be easily embedded into hosting ...materials. However, conventional fabrication methods are generally time-consuming with reproducibility issues. A more recent strategy has been proposed to develop novel FBG-based systems by encapsulating the grating within 3-D-printed structures. This process, known as 3-D printing, is characterized by several advantages like rapid prototyping, printing precision, and high customization. The possibility of quickly personalizing the 3-D-printed sensors by customizing the infill settings makes this technique very appealing for medical purposes, especially for developing smart systems. However, the influence of printing settings on the sensor response has not been yet systematically addressed. This work aimed at combining FBG with the most popular 3-D printing technique (the fused deposition modeling FDM) to develop four 3-D-printed sensors with different printing profiles. We chose two patterns (triangle and gyroid) and two infill densities (30% and 60%) to investigate their influence on the sensors’ response to strain, temperature, and relative humidity (RH), and on the hysteresis behavior. Then, we preliminary assess the sensor performance in a potential application scenario for FBG-based 3-D printing technology: the cardiorespiratory monitoring. The promising results confirm that our analysis can be considered the first effort to improve the knowledge about the influence of printing profiles on sensor performance and, consequently, pave the way to develop highly performant 3-D-printed sensors customized for specific applications.
One of the biggest challenges facing the world agriculture is feeding a growing population in a sustainable way. Therefore, global food availability is under a severe strain exacerbated by climate ...changes and biological stresses. Moreover, the content of macro and micronutrients obtained from in plant-food sources strongly depends on the plant development. An attractive strategy to increase agricultural productivity is the growth monitoring of plants and edible parts by using wearable systems. However, most of these tools measure dimensional changes uniaxially while an accurate representation of the growth distribution requires multi-point strain measurement especially for plants that show an anisotropic development. Here, we present a stretchable multi-sensor wearable system highly adaptable to the curvilinear surface of leaves and fruits for multi-directional dimensional monitoring. The proposed sensor consists of six fiber Bragg gratings (FBGs) within a biomimetic flexible substrate with a flower design. FBGs with their miniaturized size, high metrological properties, and multiplexing capacities are well-suited to this purpose. A finite element model guides the optimal design and sensors positioning within the flower-shaped matrix to exhibit an adequate strain sensitivity and negligible crosstalk effects among the six sensing elements with a reduced encumbrance. A metrological characterization is first performed followed by the application of the proposed system for in-vivo detection of dimensional changes of a leaf and fruit in both indoor and outdoor scenarios.
Highlights • We provided first data of magnetic resonance (MR) thermometry on pancreas. • We tested the effectiveness of two T1 -wighted sequences for MR-based thermometry on liver, and afterward on ...pancreas. • Fiber Bragg Grating sensors (FBGs) were employed for reference temperature monitoring. • We investigated laser ablation (LA) on pancreas as possible novelty in clinical practice.
Laser interstitial thermotherapy (LITT) is employed to destroy tumors in organs, and its outcome strongly depends on the temperature distribution inside the treated tissue. The recent introduction of ...computed tomography (CT) scan thermometry, based on the CT number dependence of the tissue with temperature, overcomes the invasiveness of other techniques used to monitor temperature during LITT. The averaged CT number (ROI = 0.02 cm(2)) of an ex vivo swine pancreas is monitored during LITT (Nd:YAG laser power of 3 W, treatment time: 120 s) at different distances from the applicator (from 4 to 30 mm). The averaged CT number shows a clear decrease during treatment: it is highest at 4 mm from the applicator (mean variation in the whole treatment of -0.256 HU s(-1)) and negligible at 30 mm, since the highest temperature increase is present close to the applicator (i.e., 45 °C at 4 mm and 25 °C at 6 mm). To obtain the relationship between CT numbers and pancreas temperature, the reference temperature was measured by 12 fiber Bragg grating sensors. The CT number decreases as a function of temperature, showing a nonlinear trend with a mean thermal sensitivity of -0.50 HU °C(-1). Results here reported are the first assessment of pancreatic CT number dependence on temperature, at the best of our knowledge. Findings can be useful to further investigate CT scan thermometry during LITT on the pancreas.
Abstract
Objective
The objective of this study was to measure the impact of video education at the time of admission for delivery on intent and participation in skin-to-skin contact (SSC) ...immediately after birth.
Methods
This study was a randomized controlled trial of educational intervention in women (
N
= 240) of 18 years or older admitted in anticipation of normal spontaneous term delivery. Alternate patients were randomized into video (
N
= 120) and no video (
N
= 120) groups. Both groups received a survey about SSC. The video group watched an educational DVD and completed a postsurvey about SSC.
Results
During the preintervention survey, 89.2% of those in the video group compared with 83.3% of those in the no video group indicated that they planned to use SSC (
p
= 0.396). After the video, 98.3% planned to do SSC after delivery (
p
< 0.001). However, only 59.8% started SSC within 5 minutes of delivery in the video group and only 49.4% started SSC within 5 minutes of delivery in the no video group (
p
= 0.17).
Conclusion
Video education alters the intention and trends toward participation in SSC within 5 minutes of delivery. Despite the plans for SSC, however, there was no significant difference in rates between the two groups. These findings support that obstacles, other than prenatal education, may affect early SSC.
Key Points
Significant obstacles impact skin-to-skin rate.
Video education alters skin-to-skin intent.
Video education can improve skin-to-skin rate.
Education can happen at the time of delivery.
Video education can impact mothers and infants.
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