Ray-based inversion accounting for scattering for biomedical ultrasound computed tomography

An efficient and accurate image reconstruction algorithm for ultrasound tomography in soft tissue is described and demonstrated, which can recover accurate sound speed distribution from acoustic time series measurements. The approach is based on a second-order iterative minimisation of the difference between the measurements and a model based on a ray-approximation to the heterogeneous Green's function. It overcomes the computational burden of full-wave solvers while avoiding the drawbacks of time-of-flight methods. Through the use of a second-order iterative minimisation scheme, applied stepwise from low to high frequencies, the effects of scattering are incorporated into the inversion

Developing an Indigenous, Entry-Level Master’s Degree Program in a Country with an Emerging OT Profession

In the Republic of Trinidad and Tobago the full range of physical, mental, psychological, and socially derived problems of occupational engagement exist. Occupational therapy is often a part of the health care team to address these challenges; however, the profession is at an emergent stage in the country. This paper describes a process used for the development of an indigenous entry-level master’s degree program in occupational therapy. The process was also supported and enhanced by the collaborative relationships among key stakeholders, including global partners. A qualitative design process was used to analyze the health care needs, barriers, and strategies that impact the sustainability of the proposed program. This included 47 survey respondents, 10 semi-structured interviews, and a focus group. The findings led to the development of curricular threads that informed the curricular framework of the program. The curricular framework will safeguard the sustainability of the program and the clinical relevance of its content and methods relative to the community the graduates will serve. Systematic review of curricular design and program outcomes is needed to enhance the intended learning experience of the occupational therapy students

A Fast and Accessible Methodology for Micro-Patterning Cells on Standard Culture Substrates Using Parafilm™ Inserts

Micropatterning techniques provide direct control over the spatial organization of cells at the sub-mm scale. Regulation of these spatial parameters is important for controlling cell fate and cell function. While micropatterning has proved a powerful technique for understanding the impact of cell organization on cell behaviour, current methods for micropatterning cells require complex, specialized equipment that is not readily accessible in most biological and bioengineering laboratories. In addition, currently available methods require significant protocol optimization to ensure reliable and reproducible patterning. The inaccessibility of current methods has severely limited the widespread use of micropatterning as a tool in both biology and tissue engineering laboratories. Here we present a simple, cheap, and fast method to micropattern mammalian cells into stripes and circular patterns using Parafilm™, a common material found in most biology and bioengineering laboratories. Our method does not require any specialized equipment and does not require significant method optimization to ensure reproducible patterning. Although our method is limited to simple patterns, these geometries are sufficient for addressing a wide range of biological problems. Specifically, we demonstrate i) that using our Parafilm™ insert method we can pattern and co-pattern ARPE-19 and MDCK epithelial cells into circular and stripe micropatterns in tissue culture polystyrene (TCPS) wells and on glass slides, ii) that we can contain cells in the desired patterns for more than one month and iii) that upon removal of the Parafilm™ insert we can release the cells from the containment pattern and allow cell migration outward from the original pattern. We also demonstrate that we can exploit this confinement release feature to conduct an epithelial cell wound healing assay. This novel micropatterning method provides a reliable and accessible tool with the flexibility to address a wide range of biological and engineering problems that require control over the spatial and temporal organization of cells

Measurement of the ultrasound attenuation and dispersion in 3D-printed photopolymer materials from 1 to 3.5 MHz

Over the past decade, the range of applications in biomedical ultrasound exploiting 3D printing has rapidly expanded. For wavefront shaping specifically, 3D printing has enabled a diverse range of new, low-cost approaches for controlling acoustic fields. These methods rely on accurate knowledge of the bulk acoustic properties of the materials; however, to date, robust knowledge of these parameters is lacking for many materials that are commonly used. In this work, the acoustic properties of eight 3D-printed photopolymer materials were characterised over a frequency range from 1 to 3.5 MHz. The properties measured were the frequency-dependent phase velocity and attenuation, group velocity, signal velocity, and mass density. The materials were fabricated using two separate techniques [PolyJet and stereolithograph (SLA)], and included Agilus30, FLXA9960, FLXA9995, Formlabs Clear, RGDA8625, RGDA8630, VeroClear, and VeroWhite. The range of measured density values across all eight materials was 1120–1180 kg · m−3, while the sound speed values were between 2020 to 2630 m · s−1, and attenuation values typically in the range 3–9 dB · MHz−1· cm−1

Disparities between research attention and burden in liver diseases: implications on uneven advances in pharmacological therapies in Europe and the USA

Effective oral therapies for hepatitis B and C have recently been developed, while there are no approved pharmacological therapies for alcoholic and non-alcoholic fatty liver diseases (ALD and NAFLD). We hypothesise that fewer advances in fatty liver diseases could be related to disparities in research attention

An accelerated version of alternating direction method of multipliers for TV minimization in EIT

Existing total variation (TV) solvers that have been applied in electrical impedance tomography (EIT) smooth the TV function in order to cope with its non-differentiability around the origin, and thus imposes some numerical errors on the solution. Furthermore, these solvers require storage of Hessian, and are thus very impractical for large-scale computations, especially 3D EIT. These shortcomings were addressed by TV solvers that are based on first-order optimization methods. However, the application of these solvers to EIT remains scarce. In this manuscript, we propose an accelerated version of a gradient-based TV solver based on augmented Lagrangian and alternating direction method of multipliers, referred to as TVAL3, and apply it to EIT. The results demonstrate the superiority of the accelerated algorithm over existing TV solvers in EIT with regard to both accuracy and speed

Refraction-corrected ray-based inversion for three-dimensional ultrasound tomography of the breast

Ultrasound tomography (UST) has seen a revival of interest in the past decade, especially for breast imaging, due to improvements in both ultrasound and computing hardware. In particular, three-dimensional UST, a fully tomographic method in which the medium to be imaged is surrounded by ultrasound transducers, has become feasible. This has led to renewed attention on UST image reconstruction algorithms. In this paper, a comprehensive derivation and study of a robust framework for large-scale bent-ray UST in 3D for a hemispherical detector array is presented. Two ray

Identification of a protein encoded in the EB-viral open reading frame BMRF2

Using monospecific rabbit sera against a peptide derived from a potential antigenic region of the Epstein-Barr viral amino acid sequence encoded in the open reading frame BMRF2 we could identify a protein-complex of 53/55 kDa in chemically induced B95-8, P3HR1 and Raji cell lines. This protein could be shown to be membrane-associated, as predicted by previous computer analysis of the secondary structure and hydrophilicity pattern, and may be a member of EBV-induced membrane proteins in lytically infected cells