Deep Neural Network-Based Visual Feedback System for Nasopharyngeal Swab Sampling.

During the 2019 coronavirus disease pandemic, robotic-based systems for swab sampling were developed to reduce burdens on healthcare workers and their risk of infection. Teleoperated sampling systems are especially appreciated as they fundamentally prevent contact with suspected COVID-19 patients. However, the limited field of view of the installed cameras prevents the operator from recognizing the position and deformation of the swab inserted into the nasal cavity, which highly decreases the operating performance. To overcome this limitation, this study proposes a visual feedback system that monitors and reconstructs the shape of an NP swab using augmented reality (AR). The sampling device contained three load cells and measured the interaction force applied to the swab, while the shape information was captured using a motion-tracking program. These datasets were used to train a one-dimensional convolution neural network (1DCNN) model, which estimated the coordinates of three feature points of the swab in 2D X-Y plane. Based on these points, the virtual shape of the swab, reflecting the curvature of the actual one, was reconstructed and overlaid on the visual display. The accuracy of the 1DCNN model was evaluated on a 2D plane under ten different bending conditions. The results demonstrate that the x-values of the predicted points show errors of under 0.590 mm from P0, while those of P1 and P2 show a biased error of about -1.5 mm with constant standard deviations. For the y-values, the error of all feature points under positive bending is uniformly estimated with under 1 mm of difference, when the error under negative bending increases depending on the amount of deformation. Finally, experiments using a collaborative robot validate its ability to visualize the actual swab's position and deformation on the camera image of 2D and 3D phantoms.

A novel arthroscopic pre-curved cannula with both flexibility and high stiffness.

BACKGROUND: Curved surgical instruments are being developed to expand the workspace of straight surgical instruments. They are required to have a small diameter and high stiffness. METHODS: We developed a double-spring pre-curved cannula (DSPC) for electrocauterization, which has curved movements controlled solely by translational motion, and high stiffness via wire tension. It comprises a straight extension spring, pre-curved flat spring and braided high-modulus polyethylene line. A handheld device was designed for intuitive DSPC manipulation. The cannula has a 3.9 mm diameter and serves as a protective tube such that the electrode can safely reach the lesion. RESULTS: Experimental results demonstrate that the DSPC has ideal curvature and maximum stiffness of 1.38 N/mm. In a cadaveric study, the DSPC reached the inferior glenohumeral ligament, which conventional surgical instruments cannot access, and surgeons successfully performed electrocauterization. CONCLUSIONS: The designed DSPC is effective for future use in forceps, curettes and surgical robots.

An active endoscope with small sweep volume that preserves image orientation for arthroscopic surgery.

BACKGROUND: Microsurgery is generally performed in narrow spaces with limited movement. Endoscopes that allow for angle changes have been developed using elastic materials, but they require a large bending space. We propose a new endoscope with a small sweep volume for angle changes. METHODS: We fabricated a prototype with a thumb-operated joystick. The image sensor is attached to the tooltip. The image signal is input to a motor control board which computes inverse kinematics and transforms it into joint angle values. Each axis is positioned according to these values. RESULTS: The tooltip sweeping volume was 104 mm3 . Surgeons at the Asan Medical Center used our endoscope to obtain images of the biceps tendon and subscapularis joints of a cadaver. CONCLUSION: Currently, a low-resolution image sensor is attached to endoscope tooltips. In the future, we will develop a high-resolution image module equipped with an ultra-small complementary metal oxide semiconductor sensor.

Effects of body movement on yaw motion in bipedal running lizard by dynamic simulation.

Lizards run quickly and stably in a bipedal gait, with their bodies exhibiting a lateral S-shaped undulation. We investigate the relationship between a lizard's bipedal running and its body movement with the help of a dynamic simulation. In this study, a dynamic theoretical model of lizard is assumed as a three-link consisting of an anterior and posterior bodies, and a tail, with morphometrics based on Callisaurus draconoides. When a lizard runs straight in a stable bipedal gait, its pelvic rotation is periodically synchronized with its gait. This study shows that the S-shaped body undulation with the yaw motion is generated by minimizing the square of joint torque. Furthermore, we performed the biomechanical simulation to figure out the relationship between the lizard's lateral body undulation and the bipedal running locomotion. In the biomechanical simulation, all joint torques significantly vary by the waist and tail' motions at the same locomotion. Besides, when the waist and tail joint angles increase, the stride length and duration of the model also increase, and the stride frequency decreases at the same running speed. It means that the lizard's undulatory body movements increase its stride and help it run faster. In this study, we found the benefits of the lizard's undulatory body movement and figured out the relationship between the body movement and the locomotion by analyzing the dynamics. In the future works, we will analyze body movements under different environments with various simulators.

Active Endoscope Preserving Image Orientation for Endonasal Skull Base Surgery.

Endonasal Skull Base Surgery has some advantages over conventional methods; however, some issues such as the need to replace the endoscope due to the fixed view, and possible invasiveness during insertion make the procedure difficult. To solve these problems, this paper proposes an active endoscope mechanism with several benefits. First, its variable direction of view can cover the wide ranges. Second, it provides a forward view, lessening the danger of damaging critical tissues while the endoscope is being inserted. Third, it can change the direction of view within a very small radius of 6.5 mm, so it can be used in a small cavity and work together with other surgical tools. We have designed the endoscope, which has 4 mm diameter. It is a simple tilting and rotation mechanism of 2-degree of freedom (DOF). It implements kinematics control to make it intuitive to operate. The image sensor attached to the distal end is fixed mechanically so that the image orientation is preserved in the direction of gravity. The experiments showed the user could intuitively control the endoscope with the master device and observe the target without swapping the endoscope. Future tests will examine clinical aspects and combination work with surgical instruments.

Tripodal oxazoline-based homochiral coordination cages with internal binding sites.

Homochiral coordination cages, which have two well-defined internal binding sites for ammonium and organoammonium ions, have been constructed by Pd(II)-mediated self-assembly of preorganized tripodal oxazolines containing pyridine pendant groups.

Artificial receptors that provides a preorganized hydrophobic environment: a biomimetic approach to dopamine recognition in water.

[structure: see text] The recognition of dopamine in water has been achieved with tripodal oxazoline-based artificial receptors, capable of providing a preorganized hydrophobic environment by rational design, which mimics a hydrophobic pocket predicted for a human D2 receptor. The receptors show an amphiphilic nature owing to the presence of hydrophilic sulfonate groups at the periphery of the tripodal oxazoline ligands, which seems to contribute in forming the preorganized hydrophobic environment. The artificial receptors recognized dopamine hydrochloride in water with reasonable selectivity among various organoammonium guests examined. The observed binding behavior of the receptors was explained by evoking guest inclusion in the preorganized hydrophobic pocket-like environment and not by simple ion-pairing interactions. The rationally predicted 1:1 inclusion binding mode was supported by binding studies such as with a reference receptor that cannot provide a similar binding pocket, Job and VT-NMR experiments, electrospray ionization mass analysis, and guest selectivity data. This study implies that an effective hydrophobic environment can be generated even from an acyclic, small molecular artificial receptor. Such a preorganized hydrophobic environment, as being utilized in biological systems, can be effectively used as a complementary binding force for the recognition of organoammonium guests such as dopamine hydrochloride in water.

Synthesis of cage-type molecules with pi-cavity and selective gas-phase cation complexation.

[structure: see text] Cage-type molecules composed of phenyl walls and caps were synthesized as hosts for the binding of ammonium and alkali metal cations through cation-pi interactions. The synthesis involved a key cyclization step, which was markedly dependent on the capping component. Binding studies by electrospray ionization mass spectrometry toward lithium, sodium, potassium, and ammonium cations showed that the cage-type molecules selectively form a 1:1 complex. A competitive binding study showed that cage 3c (R = Et, R' = OMe) has a preference toward lithium cation while cage 4b (R = Me, R' = OMe) has a similar preference toward both lithium and ammonium ion in the presence of others. This selectivity pattern was tentatively explained by the gate size of the cage-type compounds, not by their cavity size.

Breaking the C3-symmetry of chiral tripodal oxazolines: enantio-discrimination of chiral organoammonium ions.

[structure: see text] A phenylglycinol-derived tripodal oxazoline with C1-symmetry (C1-PhBTO) was synthesized, and its enantioselective recognition behavior toward alpha-chiral primary organoammonium ions was studied. The C1-PhBTO receptor showed higher selectivity with an opposite sense of enantio-discrimination compared to other C1-symmetric analogues examined but lower selectivity with the same sense of enantioselection compared to its C3-symmetric analogue. Binding studies indicated that the C1-symmetric receptors, particularly C1-PhBTO, interact with the guests in a 2:1 host-guest complex mode in stark contrast to its C3-symmetric analogues.

Hydrogenation of olefins in supercritical CO(2) catalyzed by palladium nanoparticles in a water-in-CO(2) microemulsion.

Nanometer-sized metallic palladium particles can be synthesized by hydrogen reduction of Pd2+ ions dissolved in the water core of a water-in-CO2 microemulsion. The Pd nanoparticles, stabilized by the micromeulsion and uniformly dispersed in the supercritical fluid phase, are effective catalysts for hydrogenation of olefins. Examples of rapid and efficient hydrogenation of water-soluble and CO2-soluble olefins catalyzed by the Pd nanoparticles in supercritical CO2 are given.