CP2\mathbb{C}P^2 Skyrmion Crystals in an SU(3) Magnet with a Generalized Dzyaloshinskii-Moriya Interaction

We study $\mathbb{C}P^2$ Skyrmion crystals in the ferromagnetic SU(3) Heisenberg model with a generalization of the Dzyaloshinskii-Moriya interaction and Zeeman term as a stabilizing mechanism. The model possesses two different types of Skyrmion crystal with Skyrmions that can be interpreted as bound states of two half-Skyrmions or four quarter-Skyrmions.Comment: REVTeX: 6 pages, 4 figure

A Biomechanical Approach to Investigate the Applicability of the Lake-Thomas Theory in Porcine Aorta

Robot-assisted surgeries are procedures where a physician performs surgical maneuvers by operating a robot. One of the main limitations is the difficulty in transferring the surgeon’s multiple skills onto the robotic system. Such skills include the ability to estimate the maximum applicable force before damaging the tissue. To implement this skill onto a robotic system, a mathematical model for tissue damage must be developed. The objective of this study is to measure the fracture characteristic in porcine aorta, to then investigate whether an existing fracture model can be applied onto biological tissues. Due to the similarity in the mechanical response between biological tissues and polymeric materials, the model chosen for this study was the Lake-Thomas model. This is the first paper with the aim of validating this model with biological tissues. Two main findings are reported in this investigation. We found that porcine thoracic aorta tears in a specific way which is directly correlated to the tensile direction. The second finding is that an anisotropic linear relationship exists between the critical tearing energy and the elastic modulus, and the elastic modulus to the -0.5th power. These results are discussed based on the elastin and collagen fibers, as well as established mathematical equations describing polymer mechanic

Human Foveal Cone and Müller Cells Examined by Adaptive Optics Optical Coherence Tomography

Purpose: The purpose of this study was to image and investigate the foveal microstructure of human cone and Müller cells using adaptive optics-optical coherence tomography. Methods: Six healthy subjects underwent the prototype adaptive optics-optical coherence tomography imaging, which allowed an axial resolution of 3.4 µm and a transverse resolution of approximately 3 µm. The morphological features of the individual retinal cells observed in the foveola were qualitatively and quantitatively evaluated. Results: In the six healthy subjects, the image B-scans showed hyper-reflective dots that were densely packed in the outer nuclear layer. The mean number, diameter, and density of hyper-reflective dots in the foveola were 250.8 ± 59.6, 12.7 ± 59.6 µm, and 6966 ± 1833/mm², respectively. These qualitative and quantitative findings regarding the hyper-reflective dots were markedly consistent with the morphological features of the foveal cone cell nuclei. Additionally, the images showed the funnel-shaped hyporeflective bodies running vertically and obliquely between the inner and external limiting membranes, illustrating the cell morphology of the foveal Müller cells. Conclusions: Using adaptive optics, we succeeded in visualizing cross-sectional images of the individual cone and Müller cells of the human retina in vivo. Translational Relevance: Adaptive optics-optical coherence tomography would help to improve our understanding of the pathogenesis of macular diseases

In vivo tracking transplanted cardiomyocytes derived from human induced pluripotent stem cells using nuclear medicine imaging

Introduction: Transplantation of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) is a promising treatment for heart failure. Information on long-term cell engraftment after transplantation is clinically important. However, clinically applicable evaluation methods have not yet been established. Methods: In this study, to noninvasively assess transplanted cell engraftment, human SLC5A5, which encodes a sodium/iodide symporter (NIS) that transports radioactive tracers such as 125I, 18F-tetrafluoroborate (TFB), and 99mTc-pertechnetate (99mTcO4−), was transduced into human induced pluripotent stem cells (iPSCs), and nuclear medicine imaging was used to track engrafted human iPSC-CMs. Results: To evaluate the pluripotency of NIS-expressing human iPSCs, they were subcutaneously transplanted into immunodeficient rats. Teratomas were detected by 99mTcO4− single photon emission computed tomography (SPECT/CT) imaging. NIS expression and the uptake ability of 125I were maintained in purified human iPSC-CMs. NIS-expressing human iPSC-CMs transplanted into immunodeficient rats could be detected over time using 99mTcO4− SPECT/CT imaging. Unexpectedly, NIS expression affected cell proliferation of human iPSCs and iPSC-derived cells. Discussion: Such functionally designed iPSC-CMs have potential clinical applications as a noninvasive method of grafted cell evaluation, but further studies are needed to determine the effects of NIS transduction on cellular characteristics and functions

Current Status and Future Potential of Robotic Surgery for Gastrointestinal Cancer

　Robotic surgery has built on innovations in areas such as medical engineering and optical technology. Laparoscopic surgery has been successfully adapted for gastric, colon, and rectal cancer surgeries over the past two decades with numerous clinical trials showing oncological results comparable to those of open surgery. These trials have also shown that the laparoscopic approach shortens postoperative recovery time and decreases complication rates. Another advantage of minimally invasive techniques for the resection of gastric, colon, and rectal cancers is improved visualization of the surgical field. Despite the near absence of tactile feedback, robotic surgery has overcome many of the challenges inherent in laparoscopic surgery through features such as 3D vision, stable magnification, EndoWrist instruments, physiological tremor filtering, and motion scaling. Robotic surgery is not yet widely used in esophageal cancer surgery or in a pancreaticoduodenectomy for pancreatic cancer due to anatomical difficulties and the lack of a suitable approach.　Comparative studies of robotic and laparoscopic surgery have shown similar results in terms of perioperative management, oncologic evaluation, and functional outcomes. However, it is also true that the high cost and lack of tactile feedback in robotic surgery are major limitations in terms of current robotic technology becoming the worldwide standard for minimally invasive surgery. The future of robotic surgery will require cost reduction, the development of new platforms and technologies, the creation and validation of curricula and virtual simulators, and confirmation through appropriate randomized controlled clinical trials

The interplay of KRAS mutational status with tumor laterality in non-metastatic colorectal cancer: An international, multi-institutional study in patients with known KRAS, BRAF, and MSI status

Background: Although the prognostic relevance of KRAS status in metastatic colorectal cancer (CRC) depends on tumor laterality, this relationship is largely unknown in non-metastatic CRC. Methods: Patients who underwent resection for non-metastatic CRC between 2000 and 2018 were identified from institutional databases at six academic tertiary centers in Europe and Japan. The prognostic relevance of KRAS status in patients with right-sided (RS), left-sided (LS), and rectal cancers was assessed. Results: Of the 1093 eligible patients, 378 had right-sided tumors and 715 had left-sided tumors. Among patients with RS tumors, the 5-year overall (OS) and recurrence-free survival (RFS) for patients with KRASmut versus wild-type tumors was not shown to differ significantly (82.2% vs. 83.2% and 72.1% vs. 76.7%, respectively, all p >.05). Among those with LS tumors, KRAS mutation was associated with shorter 5-year OS and RFS on both the univariable (OS: 79.4% vs. 86.1%, p =.004; RFS: 68.8% vs. 77.3%, p =.005) and multivariable analysis (OS: HR: 1.52, p =.019; RFS: HR: 1.32, p =.05). Conclusions: KRAS mutation status was independently prognostic among patients with LS tumors, but this association failed to reach statistical significance in RS and rectal tumors. These findings confirm reports in metastatic CRC and underline the possible biologic importance of tumor location

Appendiceal mucinous neoplasm: a review of eleven surgical cases in our institution

　虫垂原発粘液産生腫瘍は WHO 分類に基づき低異型度虫垂粘液性腫瘍（Low-grade appendiceal mucinous neoplasm，以下 LAMN）と粘液癌に分類される．当科にて2010年４月〜2018年11月までに外科的切除された11症例を集積検討した．　11症例の内訳は年齢が27～88歳（中央値61歳）で男女比は男７人，女４人であった．主訴は腹痛が６人で無症状が５人であった．病理診断での腫瘍最大径は３〜12 cm（平均5.9 cm）であった．術前より LAMN と疑われた症例は７例で，虫垂腺癌の術前診断に至った症例は１例であった．虫垂腫瘍との術前診断に至らなかった３症例のうち，虫垂炎の術前診断で虫垂切除術施行後に病理診断で判明したものが２例，十二指腸潰瘍穿孔で緊急手術を行った際に合併切除した虫垂組織より偶然発見されたものが１例であった．術式は虫垂切除のみが３例，回盲部切除が５例，右半結腸切除が３例であった．予定手術は６例で緊急手術が５例であった．最終病理診断（大腸癌取り扱い規約第９版に準拠）は LAMN が７例で虫垂腺癌が２例，粘液嚢胞が２例であった．術後入院期間は2〜47日（中央値12日）で，虫垂腫瘍切除に関連する術後合併症はなかった．LAMN は比較的稀な疾患であるが，腫瘍破裂により粘液が漏出することで腹膜偽粘液腫をきたす可能性がある．そのため，再発を引き起こさないためには①画像検査などでの術前診断（術中診断を含む），②術中に粘液漏出させない術式選択，③術後病理診断で判明した場合の追加治療の適否，についてその都度慎重に判断する必要がある．　LAMN は低悪性度腫瘍にも関わらず再発の危険性があるため，画像検査で疑った場合は再発防止を念頭においた術前評価と治療方針の策定が必要であり，切除後の厳重フォローも重要である．　Appendiceal mucinous neoplasm (AMN) is composed of mucinous adenocarcinoma and low-grade appendiceal mucinous neoplasm (LAMN) according to the fifth edition World Health Organization classification. Although AMN is relatively rare in clinical practice, we had eleven surgical cases of AMN from April 2010 to November 2018 and retrospectively review them in this report. The eleven cases consisted of seven men and four women, ages 27 - 88 years old (average: 65.5 y.o.). Six patients had abdominal pain upon their initial visit. Preoperative examinations made a presumptive diagnosis of LAMN in 7 cases and cancer of the appendix in 2 cases. In the other two cases, one was diagnosed after surgery for acute appendicitis, and the other was coincidently found in the appendiceal tissue that was resected during an emergent laparotomy for a perforated duodenal ulcer. Emergency operations were performed for 5 cases, whereas laparoscopic surgery was done in 4 of the cases. The following operative procedures were performed; 5 ileocecal resections, 3 right hemicolectomies, and 3 simple appendectomies. Pathological examinations concluded that 7 cases were LAMN, 2 were appendiceal adenocarcinoma, and the remaining 2 were hyperplastic mucocele. The length of hospital stay after surgery varied from 2 to 47 days (median: 12 days), with no apparent complications related to surgery in any cases. The most critical features of AMN are the potential to recur as pseudomyxoma peritonei, when the tumor is ruptured during surgery, or in case of tumor cells remaining at the resection stump. Since LAMN is specifically recognized to be low-grade malignant, several steps should be taken to minimize recurrence in addition to the standard postoperative follow-up on regular basis. These steps include assessing each preoperative state of disease adequately, selecting the most suitable procedure to reduce the risk of mucus leakage, and cautiously reviewing the necessity of additional resection based upon pathological determinations

Fracture energy of polymer gels with controlled network structures

We have investigated the fracture behaviors of tetra-arm polyethylene glycol (Tetra-PEG) gels with controlled network structures. Tetra-PEG gels were prepared by AB-type crosslink-coupling of mutually reactive tetra-arm prepolymers with different concentrations and molecular weights. This series of controlled network structures, for the first time, enabled us to quantitatively examine the Lake-Thomas model, which is the most popular model predicting fracture energies of elastomers. The experimental data showed good agreement with the Lake-Thomas model, and indicated a new molecular interpretation for the displacement length (L), the area around a crack tip within which the network strands are fully stretched. L corresponded to the three times of end-to-end distance of network strands, regardless of all parameters examined. We conclude that the Lake-Thomas model can quantitatively predict the fracture energy of polymer network without trapped entanglements, with the enhancement factor being near 3