•The first completely automated low damage and contamination free sectioning with coupled BIB–SEM for imaging beam sensitive materials.•Large area in hundreds of microns with high resolution in ...nanometres correlative microscopy and ability to focus on sites of interest for microstructural characterisation in three dimensions.•Automated SST with SE, EBSD and EDS analysis for broad range of applications, from biological to geological and metallurgical.•BIB is shown to have up to 5 times higher sputter rates compared to FIB techniques.
Here we describe the first automated fully integrated in-microscope broad ion beam (BIB) system. Ar+-BIB has several advantages over Ga+ focused ion beam (FIB) and Xe+ plasma-FIB (PFIB) methods inducing less beam damage, especially for ion beam sensitive materials. It can mill areas several orders of magnitude larger (up to millimetre scale), and is not confined to the edge of the sample with associated curtaining issues. BIB is shown to have sputter rates up to five times higher than comparable FIB techniques. This new coupled BIB–SEM system (commercial name ‘iPrep™II’) enables in-microscope surface polishing to remove contaminants or damage for two dimensional (2D) imaging, as well as automated serial section tomography (SST) by milling and imaging hundreds of slices, cost and time efficiently. The milled slice thickness can be controlled from a few nanometers up to a micrometre. A novel sample transfer, handling and interlock system allows automated and sequential BIB polishing, scanning electron microscopy (SEM) and analysis by secondary electron (SE) imaging, electron back scatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) for 3D microstructure analysis. Furthermore, insulating surfaces can be sputter coated after milling each slice to reduce charging during SEM analysis. The performance of the instrument is demonstrated through a series of case studies across the materials, earth and life sciences exploiting the imaging, crystallographic and chemical mapping capabilities. These include the study of butterfly defects in bearing steels, meta-stable intermetallic phases in bronze bearings, shale gas rock, aluminium plasma electrolytic oxide (PEO) coatings as well as liver and mouse brain tissues.
Aging and diabetes lead to protein glycation and cause dysfunction of collagen-containing tissues. The accompanying structural and functional changes of collagen significantly contribute to the ...development of various pathological malformations affecting the skin, blood vessels, and nerves, causing a number of complications, increasing disability risks and threat to life. In fact, no methods of non-invasive assessment of glycation and associated metabolic processes in biotissues or prediction of possible skin complications, e.g., ulcers, currently exist for endocrinologists and clinical diagnosis. In this publication, utilizing emerging photonics-based technology, innovative solutions in machine learning, and definitive physiological characteristics, we introduce a diagnostic approach capable of evaluating the skin complications of diabetes mellitus at the very earlier stage. The results of the feasibility studies, as well as the actual tests on patients with diabetes and healthy volunteers, clearly show the ability of the approach to differentiate diabetic and control groups. Furthermore, the developed in-house polarization-based hyperspectral imaging technique accomplished with the implementation of the artificial neural network provides new horizons in the study and diagnosis of age-related diseases.
Flexible 16 Antenna Array for Microwave Breast Cancer Detection Bahramiabarghouei, Hadi; Porter, Emily; Santorelli, Adam ...
IEEE transactions on biomedical engineering,
2015-Oct., 2015-Oct, 2015-10-00, 20151001, Letnik:
62, Številka:
10
Journal Article
Recenzirano
Radar-based microwave imaging has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues has been studied over a wide frequency band for ...this application. We design single- and dual-polarization antennas for wireless ultrawideband breast cancer detection systems using an inhomogeneous multilayer model of the human breast. Antennas made from flexible materials are more easily adapted to wearable applications. Miniaturized flexible monopole and spiral antennas on a 50-μm Kapton polyimide are designed, using a high-frequency structure simulator, to be in contact with biological breast tissues. The proposed antennas are designed to operate in a frequency range of 2-4 GHz (with reflection coefficient (S11) below -10 dB). Measurements show that the flexible antennas have good impedance matching when in different positions with different curvature around the breast. Our miniaturized flexible antennas are 20 mm × 20 mm. Furthermore, two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system. By using a reflector for the arrays, the penetration of the propagated electromagnetic waves from the antennas into the breast can be improved by factors of 3.3 and 2.6, respectively.
The ability to recover tissue deformation from visual features is fundamental for many robotic surgery applications. This has been a long-standing research topic in computer vision, however, is still ...unsolved due to complex dynamics of soft tissues when being manipulated by surgical instruments. The ambiguous pixel correspondence caused by homogeneous texture makes achieving dense and accurate tissue tracking even more challenging. In this paper, we propose a novel self-supervised framework to recover tissue deformations from stereo surgical videos. Our approach integrates semantics, cross-frame motion flow, and long-range temporal dependencies to enable the recovered deformations to represent actual tissue dynamics. Moreover, we incorporate diffeomorphic mapping to regularize the warping field to be physically realistic. To comprehensively evaluate our method, we collected stereo surgical video clips containing three types of tissue manipulation (i.e., pushing, dissection and retraction) from two different types of surgeries (i.e., hemicolectomy and mesorectal excision). Our method has achieved impressive results in capturing deformation in 3D mesh, and generalized well across manipulations and surgeries. It also outperforms current state-of-the-art methods on non-rigid registration and optical flow estimation. To the best of our knowledge, this is the first work on self-supervised learning for dense tissue deformation modeling from stereo surgical videos. Our code will be released.
Magnetic resonance fingerprinting (MRF) is a magnetic resonance imaging (MRI)-based method that can provide quantitative maps of multiple tissue properties simultaneously from a single rapid ...acquisition. Tissue property maps are generated by matching the complex signal evolutions collected at the scanner to a dictionary of signals derived using the Bloch equation simulations. However, in some circumstances, the process of dictionary generation and signal matching can be time-consuming, reducing the utility of this technique. Recently, several groups have proposed using machine learning to accelerate the extraction of quantitative maps from the MRF data. This article will provide an overview of current research that combines MRF and machine learning, as well as present original research demonstrating how machine learning can speed up dictionary generation for cardiac MRF (cMRF).
The origin of rigidity in disordered materials is an outstanding open problem in statistical physics. Previously, a class of 2D cellular models has been shown to undergo a rigidity transition ...controlled by a mechanical parameter that specifies cell shapes. Here, we generalize this model to 3D and find a rigidity transition that is similarly controlled by the preferred surface area S0: the model is solid-like below a dimensionless surface area of s 0 S 0 V ¯ 2 3 5.413 with V ¯ being the average cell volume, and fluid-like above this value. We demonstrate that, unlike jamming in soft spheres, residual stresses are necessary to create rigidity. These stresses occur precisely when cells are unable to obtain their desired geometry, and we conjecture that there is a well-defined minimal surface area possible for disordered cellular structures. We show that the behavior of this minimal surface induces a linear scaling of the shear modulus with the control parameter at the transition point, which is different from the scaling observed in particulate matter. The existence of such a minimal surface may be relevant for biological tissues and foams, and helps explain why cell shapes are a good structural order parameter for rigidity transitions in biological tissues.
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•An innovative optode comprising three parts for sensing Be2+ levels in environmental and biological matrices.•The optode composed of polyvinyl chloride base, dihydroxyphenyl-diazenyl ...ligand, and aliquat 336 as an extractant.•The application of reused polymer inclusion membrane (PIM) in the evaluation of Be2+ was examined.•The used instrument, visible spectrophotometry, is convenient and available in all quality control labs.•The optode instrument exhibits complete reversibility and can be easily restored using a NaF (0.5 mol/L) solution.
Beryllium (Be2+) is a type of alkaline earth-divalent metal that enters many strategic industries. The work environment limits concentrations of beryllium is in the range of 0.01 – 1.0 μg mL−1 (ppm), where concentrations exceeding 5.0 ppm of Be2+ lead to acute toxicity, causing pulmonary edema and chemical pneumonitis. Herein, Be2+ was measured selectively in situ down to ultralow concentration levels utilizing a fabricated sensitive polymer inclusion membrane (PIM) as an immobilizing non-plasticized colorimetric optical sensor (optode). The PIM-sensitive optode has been created using an encapsulation method with polyvinyl chloride (PVC) as a polymer base, an (E)-6-(4-((2,5-dihydroxyphenyl)diazenyl)phenyl)-2-oxo-4-phenyl-1,2-dihydropyridine-3-carbonitrile (DDP-OPDC) as a selective ligand, and Aliquat 336 as an enhancer extractant. The linear dynamic range of the various standard measurements ranged between 5.0 and 145 ng mL−1 with excellent sensitivity down to 1.6 ng mL−1. Moreover, the manufactured optode was reusable and had sustainable mechanical strength. The method has also successfully quantified Be2+ in the livers and muscles of bovine, chicken, and pork (recovery %; 98.0–––102.3 %) in addition to Be2+ analysis in contaminated tap, mineral, and well water (recovery %; in the range of 93.6–––103.3 %). With an assessment duration of 10 min at a maximum absorbance of 622 nm, the colorimetric evaluations of Be2+ in various samples (water and biological) were rapid, reliable, and reproducible. Furthermore, the obtained results by the developed optode matched excellently those obtained by the comparison atomic absorption spectrometry method.
A major challenge in image-guided laparoscopic surgery is that structures of interest often deform and go, even if only momentarily, out of view. Methods which rely on having an up-to-date impression ...of those structures, such as registration or localisation, are undermined in these circumstances. This is particularly true for soft-tissue structures that continually change shape - in registration, they must often be re-mapped. Furthermore, methods which require 'revisiting' of previously seen areas cannot in principle function reliably in dynamic contexts, drastically weakening their uptake in the operating room. We present a novel approach for learning to estimate the deformed states of previously seen soft tissue surfaces from currently observable regions, using a combined approach that includes a Graph Neural Network (GNN). The training data is based on stereo laparoscopic surgery videos, generated semi-automatically with minimal labelling effort. Trackable segments are first identified using a feature detection algorithm, from which surface meshes are produced using depth estimation and delaunay triangulation. We show the method can predict the displacements of previously visible soft tissue structures connected to currently visible regions with observed displacements, both on our own data and porcine data. Our innovative approach learns to compensate non-rigidity in abdominal endoscopic scenes directly from stereo laparoscopic videos through targeting a new problem formulation, and stands to benefit a variety of target applications in dynamic environments. Project page for this work: https://gitlab.com/nct_tso_public/seesaw-soft-tissue-deformation
Nowadays, dynamically developing optical (photonic) technologies play an ever-increasing role in medicine. Their adequate and effective implementation in diagnostics, surgery, and therapy needs ...reliable data on optical properties of human tissues, including skin. This paper presents an overview of recent results on the measurements and control of tissue optical properties. The issues reported comprise a brief review of optical properties of biological tissues and efficacy of optical clearing (OC) method in application to monitoring of diabetic complications and visualization of blood vessels and microcirculation using a number of optical imaging technologies, including spectroscopic, optical coherence tomography, and polarization- and speckle-based ones. Molecular modeling of immersion OC of skin and specific technique of OC of adipose tissue by its heating and photodynamic treatment are also discussed.
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