Flow Pattern and Switching Mechanism in a Wall Attachment Type Fluid Amplifier

An experimental investigation has been performed to determine the steady-state pattern and the switching mechanism of the airflow in a wall attachment type fluid amplifier. With the experimental results, it is shown that the jet flow is considerably affected by the splitter distance and the step height of the device, and switching action of the flow caused by a step control jet, i.e. the switching time and the critical velocity range of control jet, is determined. By using some simple assumptions, approximate calculation have been carried out to obtain the relations between the switching time and the step control jet flow, and are compared with the experimental results

The Effectiveness of Simultaneous Combination Therapy Using S-1 and Nedaplatin with Radiation for Five Cases of Maxillary Cancer

In our department, we provide treatment for malignant head and neck tumors with the goal of preserving organs and function. We report the treatment outcomes for five patients with maxillary cancer who underwent S-1 and nedaplatin treatment with concurrent radiation therapy (SN therapy) in our department from April 2005 to March 2009. The patients included one case classified as T2N0M0 and four cases classified as T4N0M0. All patients were male and were aged between 29 and 67 years with a mean age of 55.6 years. Among the five cases, four achieved cancer-free survival with preservation of all functions after undergoing treatment. In the remaining case, the tumor did not disappear but was locally controlled via superselective arterial injection and CyberKnife treatment; however, pulmonary metastasis occurred and the patient is surviving with cancer. SN therapy has allowed a reduction in the extent of surgery required and the preservation of organs and function. It will be necessary to study an increased number of cases in the future to determine the survival rate and the effectiveness of organ and function preservation in maxillary cancer patients after SN therapy

Low-grade Myofibroblastic Sarcoma at the Base of the Tongue

Low-grade myofibroblastic sarcoma (LGMS) represents a distinct atypical myofibroblastic tumor that occurs at several sites, primarily within the head and neck regions. A painless, enlarged mass is the most common clinical presentation, but a definitive diagnosis requires both histopathological and immunohistochemical analyses. Histologically, LGMS commonly presents as a cellular lesion composed of spindle-shaped tumor cells arranged primarily in fascicles with a diffusely infiltrative pattern. Immunohistochemically, LGMS shows positive staining for at least one myogenic marker, such as desmin or muscle actin. Here we report a case of LGMS in the base of the tongue. Our case showed positive immunostaining for desmin and vimentin, and was thus diagnosed as LGMS. The patient received surgery, but no chemotherapy or radiotherapy, and was completely without evidence of the disease 38 months after the surgery

A novel locally operated master-slave robot system for single-incision laparoscopic surgery

Purpose: Single-incision laparoscopic surgery (SILS) provides more cosmetic benefits than conventional laparoscopic surgery but presents operational difficulties. To overcome this technical problem, we have developed a locally operated master-slave robot system that provides operability and a visual field similar to conventional laparoscopic surgery. Material and methods: A surgeon grasps the master device with the left hand, which is placed above the abdominal wall, and holds a normal instrument with the right hand. A laparoscope, a slave robot, and the right-sided instrument are inserted through one incision. The slave robot is bent in the body cavity and its length, pose, and tip angle are changed by manipulating the master device; thus the surgeon has almost the same operability as with normal laparoscopic surgery. To evaluate our proposed system, we conducted a basic task and an ex vivo experiment. Results: In basic task experiments, the average object-passing task time was 9.50 sec (SILS cross), 22.25 sec (SILS parallel), and 7.23 sec (proposed SILS). The average number of instrument collisions was 3.67 (SILS cross), 14 (SILS parallel), and 0.33 (proposed SILS). In the ex vivo experiment, we confirmed the applicability of our system for single-port laparoscopic cholecystectomy. Conclusion: We demonstrated that our proposed robot system is useful for single-incision laparoscopic surgery.ArticleMINIMALLY INVASIVE THERAPY & ALLIED TECHNOLOGIES. 23(6):326-332 (2014)journal articl

Video Observations of Tiny Near-Earth Objects with Tomo-e Gozen

We report the results of video observations of tiny (diameter less than 100 m) near-Earth objects (NEOs) with Tomo-e Gozen on the Kiso 105 cm Schmidt telescope. A rotational period of a tiny asteroid reflects its dynamical history and physical properties since smaller objects are sensitive to the YORP effect. We carried out video observations of 60 tiny NEOs at 2 fps from 2018 to 2021 and successfully derived the rotational periods and axial ratios of 32 NEOs including 13 fast rotators with rotational periods less than 60 s. The fastest rotator found during our survey is 2020 HS7 with a rotational period of 2.99 s. We statistically confirmed that there is a certain number of tiny fast rotators in the NEO population, which have been missed with any previous surveys. We have discovered that the distribution of the tiny NEOs in a diameter and rotational period (D-P) diagram is truncated around a period of 10 s. The truncation with a flat-top shape is not explained well either by a realistic tensile strength of NEOs or suppression of YORP by meteoroid impacts. We propose that the dependence of the tangential YORP effect on the rotational period potentially explains the observed pattern in the D-P diagram.Comment: This article is published in PASJ as open access, published by OUP (https://doi.org/10.1093/pasj/psac043). 27 pages, 16 figure