ADVANCED IMAGING AND ROBOTICS TECHNOLOGIES FOR MEDICAL APPLICATIONS

Due to the importance of surgery in the medical field, a large amount of research has been conducted in this area. Imaging and robotics technologies provide surgeons with the advanced eye and hand to perform their surgeries in a safer and more accurate manner. Recently medical images have been utilized in the operating room as well as in the diagnostic stage. If the image to patient registration is done with sufficient accuracy, medical images can be used as "a map" for guidance to the target lesion. However, the accuracy and reliability of the surgical navigation system should be sufficiently verified before applying it to the patient. Along with the development of medical imaging, various medical robots have also been developed. In particular, surgical robots have been researched in order to reach the goal of minimal invasiveness. The most important factors to consider are determining the demand, the strategy for their use in operating procedures, and how it aids patients. In addition to the above considerations, medical doctors and researchers should always think from the patient's point of view. In this article, the latest medical imaging and robotic technologies focusing on surgical applications are reviewed based upon the factors described in the above. © 2011 Copyright Taylor and Francis Group, LLC.1

Spectroscopy along Multiple, Lensed Sightlines through Outflowing Winds in the Quasar SDSS J1029+2623

We study the origin of absorption features on the blue side of the C IV broad emission line of the large-separation lensed quasar SDSS J1029+2623 at z_em ~ 2.197. The quasar images, produced by a foreground cluster of galaxies, have a maximum separation angle of ~ 22".5. The large angular separation suggests that the sight-lines to the quasar central source can go through different regions of outflowing winds from the accretion disk of the quasar, providing a unique opportunity to study the structure of outflows from the accretion disk, a key ingredient for the evolution of quasars as well as for galaxy formation and evolution. Based on medium- and high-resolution spectroscopy of the two brightest images conducted at the Subaru telescope, we find that each image has different intrinsic levels of absorptions, which can be attributed either to variability of absorption features over the time delay between the lensed images, ~ 774 days, or to the fine structure of quasar outflows probed by the multiple sight-lines toward the quasar. While both these scenarios are consistent with the current data, we argue that they can be distinguished with additional spectroscopic monitoring observations.Comment: 17 pages, including 7 figures; accepted for publication in the Astronomical Journa

Concept of Virtual Incision for Minimally Invasive Surgery

Minimally invasive surgery has been introduced to various surgical fields for its benefits such as smaller scars and less pain as compared to open surgery. Highly skilled surgical techniques are required for surgeons to conduct minimally invasive surgery with fewer ports, whereas minimally invasive surgery has a number of advantages for patients. Single-incision laparoscopic surgery (SILS), in which surgical instruments and a laparoscope are inserted through a single port, has better cosmetic results than conventional multi-incision surgery; moreover, the scar is invisible when the port is opened in navel. However, instrument collisions and visual defects often occur due to the limited space of the single opening. We propose a new surgical approach entitled “virtual incision” that enables surgeons to increase the number of openings virtually. Using our approach, we have developed two types of master-slave surgical robot systems for SILS—remote-operated and local-operated systems—which have operability close to that of multiple-incision surgery. Through evaluation of these systems, we demonstrated that the visual field and operability during virtual incision surgery are similar to those of conventional multi-incision surgery. Our surgical approach can be applied to not only single-incision surgery but also multi-incision surgery, and is very likely to improve operability

Line-of-sight structure of troughs identified in Subaru Hyper Suprime-Cam Year 3 weak lensing mass maps

We perform the weak lensing mass mapping analysis to identify troughs, which are defined as local minima in the mass map. Since weak lensing probes projected matter along the line-of-sight, these troughs can be produced by single voids or multiple voids projected along the line-of-sight. To scrutinise the origins of the weak lensing troughs, we systematically investigate the line-of-sight structure of troughs selected from the latest Subaru Hyper Suprime-Cam (HSC) Year 3 weak lensing data covering $433.48 \, \mathrm{deg}^2$. From a curved sky mass map constructed with the HSC data, we identify 15 troughs with the signal-to-noise ratio higher than $5.7$ and address their line-of-sight density structure utilizing redshift distributions of two galaxy samples, photometric luminous red galaxies observed by HSC and spectroscopic galaxies detected by Baryon Oscillation Spectroscopic Survey. While most of weak lensing signals due to the troughs are explained by multiple voids aligned along the line-of-sight, we find that two of the 15 troughs potentially originate from single voids at redshift $\sim 0.3$. The single void interpretation appears to be consistent with our three-dimensional mass mapping analysis. We argue that single voids can indeed reproduce observed weak lensing signals at the troughs if these voids are not spherical but are highly elongated along the line-of-sight direction.Comment: 14 pages, 12 figures, submitted to MNRA

Dark Quest. I. Fast and Accurate Emulation of Halo Clustering Statistics and Its Application to Galaxy Clustering

We perform an ensemble of $N$-body simulations with $2048^3$ particles for 101 flat $w$CDM cosmological models sampled based on a maximin-distance Sliced Latin Hypercube Design. By using the halo catalogs extracted at multiple redshifts in the range of $z=[0,1.48]$, we develop Dark Emulator, which enables fast and accurate computations of the halo mass function, halo-matter cross-correlation, and halo auto-correlation as a function of halo masses, redshift, separations and cosmological models, based on the Principal Component Analysis and the Gaussian Process Regression for the large-dimensional input and output data vector. We assess the performance of the emulator using a validation set of $N$-body simulations that are not used in training the emulator. We show that, for typical halos hosting CMASS galaxies in the Sloan Digital Sky Survey, the emulator predicts the halo-matter cross correlation, relevant for galaxy-galaxy weak lensing, with an accuracy better than $2\%$ and the halo auto-correlation, relevant for galaxy clustering correlation, with an accuracy better than $4\%$. We give several demonstrations of the emulator. It can be used to study properties of halo mass density profiles such as the mass-concentration relation and splashback radius for different cosmologies. The emulator outputs can be combined with an analytical prescription of halo-galaxy connection such as the halo occupation distribution at the equation level, instead of using the mock catalogs, to make accurate predictions of galaxy clustering statistics such as the galaxy-galaxy weak lensing and the projected correlation function for any model within the $w$CDM cosmologies, in a few CPU seconds.Comment: 46 pages, 47 figures; version accepted for publication in Ap

A Comprehensive Study on Galaxies at z~9-17 Found in the Early JWST Data: UV Luminosity Functions and Cosmic Star-Formation History at the Pre-Reionization Epoch

We conduct a comprehensive study on dropout galaxy candidates at $z\sim 9-17$ using the first 90 arcmin$^2$ JWST/NIRCam images taken by the early release observations (ERO) and early release science (ERS) programs. With the JWST simulation images, we find that a number of foreground interlopers are selected with a weak photo-$z$ determination ($\Delta \chi^2>4$). We thus carefully apply a secure photo-$z$ selection criterion ($\Delta \chi^2>9$) and conventional color criteria with confirmations of the ERO NIRSpec spectroscopic redshifts, and obtain a total of 25 dropout galaxies at $z\sim 9-17$, including two candidates at $z_\mathrm{phot}=16.45_{-0.32}^{+0.09}$ and $16.66_{-0.34}^{+1.86}$. We perform thorough comparisons of dropout galaxies found in our work with recent JWST studies, and conclude that our galaxy sample is reliable enough for statistical analyses. We derive the UV luminosity functions at $z\sim 9-17$, and confirm that our UV luminosity functions at $z\sim 9$ and $12$ agree with those determined by previous HST and JWST studies. The cosmic star-formation rate density decreases from $z\sim 9$ to $12$, and perhaps to $17$, but the densities at $z\sim12-17$ are higher than the constant star formation efficiency model. Interestingly, there are six bright galaxy candidates at $z\sim 11-17$ with $M_{\rm UV}<-19.5$ whose stellar masses are very high, $10^{8-9} M_\odot$. Because a majority ($\sim 70\%$) of these galaxies shows no signatures of AGNs in their morphologies, the high cosmic star-formation rate densities and the existence of these stellar massive galaxies are explained by no suppression of star-formation by the UV background radiation at the pre-reionization epoch or an efficient UV radiation production by Population III-like star formation.Comment: 36 pages, 19 figures. Submitted to ApJS. Comments welcom

Function of Epirubicin-Conjugated Polymeric Micelles in Sonodynamic Therapy

The combinatory use of high-intensity focused ultrasound (HIFU) and epirubicin (EPI)-conjugated polymeric micellar nanoparticles (NC-6300) is thought to be a less invasive and more efficient method of cancer therapy. To investigate the mechanism underlying the combination effect, we examined the effect of trigger-pulsed HIFU (TP-HIFU) and NC-6300 from the perspective of reactive oxygen species (ROS) generation, which is considered the primary function of sonodynamic therapy (SDT), and changes in drug characteristics. TP-HIFU is an effective sequence for generating hydroxyl radicals to kill cancer cells. EPI was susceptible to degradation by TP-HIFU through the production of hydroxyl radicals. In contrast, EPI degradation of NC-6300 was suppressed by the hydrophilic shell of the micelles. NC-6300 also exhibited a sonosensitizer function, which promoted the generation of superoxide anions by TP-HIFU irradiation. The amount of ROS produced by TP-HIFU reached a level that caused structural changes to the cellular membrane. In conclusion, drug-conjugated micellar nanoparticles are more desirable for SDT because of accelerated ROS production and drug protection from ROS. Furthermore, a combination of NC-6300 and TP-HIFU is useful for minimally invasive cancer therapy with cooperative effects of HIFU-derived features, antitumor activity of EPI, and increased ROS generation to cause damage to cancer cells