Towards Non-contact 3D Ultrasound for Wrist Imaging

Objective: The objective of this work is an attempt towards non-contact freehand 3D ultrasound imaging with minimal complexity added to the existing point of care ultrasound (POCUS) systems. Methods: This study proposes a novel approach of using a mechanical track for non-contact ultrasound (US) scanning. The approach thus restricts the probe motion to a linear plane, to simplify the acquisition and 3D reconstruction process. A pipeline for US 3D volume reconstruction employing an US research platform and a GPU-based edge device is developed. Results: The efficacy of the proposed approach is demonstrated through ex-vivo and in-vivo experiments. Conclusion: The proposed approach with the adjustable field of view capability, non-contact design, and low cost of deployment without significantly altering the existing setup would open doors for up gradation of traditional systems to a wide range of 3D US imaging applications. Significance: Ultrasound (US) imaging is a popular clinical imaging modality for the point-of-care bedside imaging, particularly of the wrist/knee in the pediatric population due to its non-invasive and radiation free nature. However, the limited views of tissue structures obtained with 2D US in such scenarios make the diagnosis challenging. To overcome this, 3D US imaging which uses 2D US images and their orientation/position to reconstruct 3D volumes was developed. The accurate position estimation of the US probe at low cost has always stood as a challenging task in 3D reconstruction. Additionally, US imaging involves contact, which causes difficulty to pediatric subjects while monitoring live fractures or open wounds. Towards overcoming these challenges, a novel framework is attempted in this work.Comment: 9 Pages, 11 figure

A Simplified 3D Ultrasound Freehand Imaging Framework Using 1D Linear Probe and Low-Cost Mechanical Track

Ultrasound imaging is the most popular medical imaging modality for point-of-care bedside imaging. However, 2D ultrasound imaging provides only limited views of the organ of interest, making diagnosis challenging. To overcome this, 3D ultrasound imaging was developed, which uses 2D ultrasound images and their orientation/position to reconstruct 3D volumes. The accurate position estimation of the ultrasound probe at low cost has always stood as a challenging task in 3D reconstruction. In this study, we propose a novel approach of using a mechanical track for ultrasound scanning, which restricts the probe motion to a linear plane, simplifying the acquisition and hence the reconstruction process. We also present an end-to-end pipeline for 3D ultrasound volume reconstruction and demonstrate its efficacy with an in-vitro tube phantom study and an ex-vivo bone experiment. The comparison between a sensorless freehand and the proposed mechanical track based acquisition is available online (shorturl.at/jqvX0).Comment: 4 pages, 4 figure

A study on adsorption of gases in the thin film nanocomposites

Separation of greenhouse gases through polymeric thin film by the selective transport of gas are immense advantages such as light weight, economical, high process flexibility and less space requirement. The thin film technology is used in post combustion process as well as pre combustion processes. This thin film mixed matrix composites (MMC) is prepared using inorganic nanofiller and polymer matrix. In this study, the effect of Lanthanum Oxide (La2O3) nanofiller on the N2 gas adsorption properties of polysulfone (PSf) composite is reported. The solvent evaporation technique is used for synthesizing the film composite. To complete the polymerization of the thin film, the film kept in oven at 90°C for 210 minutes. The morphology of the thin film composite is investigated by Field Emission Scanning Electron Microscope (FESEM) and the chemical structure of the composite is also confirmed through Fourier transform infrared spectroscopy (FT-IR). The performances of the thin film on adsorption are characterized by gas adsorption techniques in measurement of N2 gas. The La2O3 thin film composite significantly improved (31%) N2 gas adsorption when compared to the neat thin fil

Crystal structures of two stilbazole derivatives: bis{(E)-4-[4-(diethylamino)styryl]-1-methylpyridin-1-ium} tetraiodidocadmium(II) and (E)-4-[4-(diethylamino)styryl]-1-methylpyridin-1-ium 4-methoxybenzenesulfonate monohydrate

The title molecular salts, (C18H23N2)2[CdI4], (I), and C18H23N2+·C7H7O4S−·H2O, (II), are stilbazole, or 4-styrylpyridine, derivatives. The cation, (E)-4-[4-(diethylamino)styryl]-1-methylpyridin-1-ium, has a methyl group attached to pyridine ring and a diethyl amine group attached to the benzene ring. The asymmetric unit of salt (I), comprises one cationic molecule and half a CdI4 dianion. The Cd atom is situated on a twofold rotation axis and has a slightly distorted tetrahedral coordination sphere. In (II), the anion consists of a 4-methoxybenzenesulfonate and it crystallizes as a monohydrate. In both salts, the cations adopt an E configuration with respect to the C=C bond and the pyridine and benzene rings are inclined to each other by 10.7 (4)° in (I) and 4.6 (2)° in (II). In the crystals of both salts, the packing is consolidated by offset π–π stacking interactions involving the pyridinium and benzene rings, with centroid–centroid distances of 3.627 (4) Å in (I) and 3.614 (3) Å in (II). In the crystal of (II), a pair of 4-methoxybenzenesulfonate anions are bridged by Owater—H...Osulfonate hydrogen bonds, forming loops with an R24(8) motif. These four-membered units are then linked to the cations by a number of C—H...O hydrogen bonds, forming slabs lying parallel to the ab plane

Solvent casting-assisted synthesis of thermally responsive shape memory polymer and its composites

The present study illustrates a simple and universally applicable method of synthesizing a new thermal stimuli-responsive thermoplastic shape memory polymer (SMP) and its composites through solvent casting method followed by the hot-pressing technique using polymers like polyvinyl acetate, polysulfone and polystyrene. The process parameters have been optimized to get a uniform film without any phase separation. Polyaniline (PANI), Al2O3, TiO2 and their combinations with PANI such as Al2O3–TiO2, Al2O3–PANI, and TiO2–PANI have been used as fillers to obtain the shape memory polymer composites (SMPCs). Under the thermal stimulus, the shape recovery rate of the SMPC containing Al2O3–PANI hybrid filler was faster, having a quick response time (150 s) compared to the response time of the neat SMP (210 s). Moreover, the SMP containing Al2O3 + TiO2 filler exhibited a higher Young’s modulus (˃ 62%) compared to the neat SMP. The maximum stress of 37 MPa and 4.5% recoverable strain was observed in the SMP containing Al2O3 + TiO2 hybrid filler. Interestingly, no stored strain evolved upon cooling below Tg. The effect of physical aging on the mechanical and thermomechanical properties of SMP and its composites was studied. The synthesized SMP polymer is environmentally friendly and showed an excellent shape memory effect exhibiting a high Tg (~ 80 °C), self-healing property and good mechanical properties. Due to the multifunctional properties of the newly designed SMP and its composite, it may be a promising material for load-bearing applications

Tailored poly(ethylene) glycol dimethacrylate based shape memory polymer for orthopedic applications

Shape-memory polymers (SMPs) are stimuli-responsive materials known for their outstanding ability to be actuated from temporary shape into original shape. Because of this unique functionality SMPs are promising materials for diverse technological applications including smart biomedical devices. In this article, the work has been focused towards tailoring the SMP precursor and crosslinker wt% to obtain biocompatible acrylate based shape memory polymer with glass transition temperature (Tg) close to human body temperature. Methacrylate based shape memory polymer networks are synthesized via free radical polymerization by varying the wt% of t-butyl acrylate (tBA) and poly(ethylene glycol) dimethacrylate (PEGDMA) as crosslinker. The Tg is found to increase from 28 to 45 °C with increasing tBA amount. The SMP synthesized from 70 wt% of tBA and 30 wt% of PEGDMA possess Tg close to human body temperature and is tested for cytotoxicity with two different cell lineages, osteosarcoma (MG-63) cells, and human keratinocyte (HaCaT) cells. The synthesized SMP is found to be non-cytotoxic. Thus the investigated biocompatible shape memory polymer network can be a promising soft substrate for passive thermomechanical stimulation which can adapt and meet specific needs of in vitro or in vivo orthopedic Superior Labrum Anterior and Posterior (SLAP) medical devices

Effect of the addition of diurethane dimethacrylate on the chemical and mechanical properties of tBA-PEGDMA acrylate based shape memory polymer network

There is a great demand for the synthesis of acrylate based thermoset shape memory polymer (SMP) associated with one monomer and one crosslinker such as tert-butyl acrylate (t-BA) with poly (ethylene glycol) dimethacrylate (PEGDMA). The present work describes the synthesis of a new thermoset SMP wherein a second monomer such as diurethane dimethacrylate (DUDMA) has been added to the existing tBA + PEGDMA SMP matrix. The synthesized thermoset shape memory polymer exhibited a glass transition temperature (Tg) of 55 °C, higher Young's Modulus of 3.23 GPa, transmittance of 95% and 100% shape recovery. The SMP exhibited response to both thermal and chemical stimuli. The shape recovery rate of the SMP network is 20 s compared to 24 s observed for SMP based on tBA + PEGDMA. The obtained SMP is very transparent and possesses higher stiffness (8 MPa) and hence may be suitable for biomedical shape memory lens and orthopedic application

Tailored poly(ethylene) glycol dimethacrylate based shape memory polymer for orthopedic applications

Shape-memory polymers (SMPs) are stimuli-responsive materials known for their outstanding ability to be actuated from temporary shape into original shape. Because of this unique functionality SMPs are promising materials for diverse technological applications including smart biomedical devices. In this article, the work has been focused towards tailoring the SMP precursor and crosslinker wt% to obtain biocompatible acrylate based shape memory polymer with glass transition temperature (Tg) close to human body temperature. Methacrylate based shape memory polymer networks are synthesized via free radical polymerization by varying the wt% of tbutyl acrylate (tBA) and poly(ethylene glycol) dimethacrylate (PEGDMA) as crosslinker. The Tg is found to increase from 28 to 45 °C with increasing tBA amount. The SMP synthesized from 70 wt% of tBA and 30 wt% of PEGDMA possess Tg close to human body temperature and is tested for cytotoxicity with two different cell lineages, osteosarcoma (MG-63) cells, and human keratinocyte (HaCaT) cells. The synthesized SMP is found to be non-cytotoxic. Thus the investigated biocompatible shape memory polymer network can be a promising soft substrate for passive thermomechanical stimulation which can adapt and meet specific needs of in vitro or in vivo orthopedic Superior Labrum Anterior and Posterior (SLAP) medical devices

A novel shape memory polymer composites with grafted hydroxyapatite nanoparticles for high strength and stiffness applications

Shape memory polymer (SMP) composites have evolved uniquely, employing nanoscale fillers, which add multifunctionality to the basic resin. In this work, the effect of inorganic, grafted hydroxyapatite (g-HAp) nanoparticles on the dynamic (mechanical), thermo-mechanical and microstructural properties of copolymer, based on diurethane dimethacrylate (DUDMA), (t-butyl acrylate (tBA), and crosslinker poly(ethylene glycol) dimethacrylate (PEGDMA), has been investigated. The agglomeration of nanofillers is limited by using PEG dimethacrylate monomer to graft HAp nanoparticles. Importantly, it is observed that mixing DUDMA in (tBA + PEGDMA) has improved the Young's Modulus of SMP composite to 5.4 GPa at RT (comparable to aircraft grade resin) with a glass transition temperature (Tg) of 55°C. Tensile stress is high as 51.46 MPa with improved strain at failure from 0.07% to 0.05%. The elongation strains of 4–8% are achieved, which provide the required strain compatibility to develop aerospace SMPs as well as SMP composites for structural and bio-medical applications