Cutting characteristics of twist drill having cutting edges for drilling and reaming

Masato Okada,Naoki Asakawa,Yusuke Fujita,Makoto Nikawa 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.5

In this study, the cutting characteristics of a drill reamer, which has conventional twist drill cutting edges appended for reaming, wereinvestigated. A drill reamer has three types of cutting edges, whose roles are drilling, semi-finishing, and finishing. The cutting characteristicsof a conventional twist drill were compared to those of the drill reamer. The cutting characteristics were evaluated using the thrustforce, cutting torque, surface roughness, wear behavior of the cutting edges, and cutting edge temperature. The study used a workpiecemade of carbon steel. The temperature of the cutting edge for reaming reached a maximum value of approximately 420°C, even thoughthe depth of the cut was very small. The inner surface roughness with the drill reamer was superior to that with the conventional drill,even under dry and low-speed cutting conditions. The abrasive wear observed on the margin face of the cutting edge used for reaming.

Pneumovaginoscopy-assisted radical hysterectomy for early-stage cervical cancer: a novel bidirectional approach for tumor spillage prevention and R0 resection

Masato Kita,Yusuke Butsuhara,Yoji Hisamatsu,Takuya Yokoe,Hidetaka Okada 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.6

Objective: This study evaluated the feasibility and outcomes of pneumovaginoscopy-assisted radical hysterectomy (PVRH) for cervical cancer up to stage IIA using a bidirectional fasciaoriented and nerve-sparing surgical approach. Methods: This retrospective observational cohort study examined the operative outcomes and prognoses of patients who underwent PVRH (n=59) for up to stage IIA cervical cancer. The basic procedure was Kyoto B2 (Viper Type II nerve-sparing) radical hysterectomy and pelvic lymphadenectomy through simultaneous vaginal and abdominal (open or laparoscopic) approaches. In all cases, pneumovaginoscopy (PV) was used to create a vaginal cuff and dissect the paracolpium and paracervical endopelvic fascia to minimize nerve damage. Results: Thirty-eight (64.4%) patients had stage IB1 cancer. Seven (11.9%) had vaginal invasion (stage IIA1, n=4; IIA2, n=3). The abdominal approach was open in 38 cases and laparoscopic in 21. Adjuvant therapy was administered to 24 patients (41%); one patient received concurrent chemoradiotherapy for gastric-type adenocarcinoma. There were three (6.1%) intraoperative complications (CO2 gas embolism [n=1], sigmoid colon musculosa injury [n=1], and ureteral injury [n=1]) and 8 (14%) postoperative complications (lymphedema with cellulitis [n=4], vaginal cuff dehiscence [n=1], sub-ileus [n=1], symptomatic lymphocyst [n=l], and ureterovaginal fistula [n=1]). The median urination recovery period was 3 days. Microscopic R0 was achieved in all cases. The median follow-up was 44.5 (2–122) months, and no recurrence occurred. Conclusion: PVRH is a new fascia-oriented and nerve-sparing surgery for early-stage cervical cancer. Further, it has favorable operative outcomes and good prognoses, similar to those of adjacent pelvic surgery such as trans-anal total mesorectal excision and radical prostatectomy.

Recovery of Spermatogenesis Following Cancer Treatment with Cytotoxic Chemotherapy and Radiotherapy

Keisuke Okada,Masato Fujisawa 대한남성과학회 2019 The World Journal of Men's Health Vol.37 No.2

The survival rates of boys and men with cancer have increased due to advances in cancer treatments; however, maintenance of quality of life, including fertility preservation, remains a major issue. Fertile male patients who receive radiation and/or chemotherapy face temporary, long-term, or permanent gonadal damage, particularly with exposure to alkylating agents and whole-body irradiation, which sometimes induce critical germ cell damage. These cytotoxic treatments have a significant impact on a patient’s ability to have their own biological offspring, which is of particular concern to cancer patients of repro-ductive age. Therefore, various strategies are needed in order to preserve male fertility. Sperm cryopreservation is an effective method for preserving spermatozoa. Advances have also been achieved in pre-pubertal germ cell storage and research to generate differentiated male germ cells from various types of stem cells, including embryonic stem cells, induced pluripotent stem cells, and spermatogonial stem cells. These approaches offer hope to many patients in whom germ cell loss is associ-ated with sterility, but are still experimental and preliminary. This review examines the current understanding of the effects of chemotherapy and radiation on male fertility.

Perspective of Small-Molecule AdipoR Agonist for Type 2 Diabetes and Short Life in Obesity

Miki Okada-Iwabu,Masato Iwabu,Kohjiro Ueki,Toshimasa Yamauchi,Takashi Kadowaki 대한당뇨병학회 2015 Diabetes and Metabolism Journal Vol.39 No.5

Obesity associated with unhealthy diet and lack of exercise is shown to contribute to the onset and/or aggravation of the metabolic syndrome and diabetes, thus placing affected individuals at increased risk of cardiovascular disease and cancer. Plasma adiponectin levels are decreased in obesity, which causes insulin resistance and diabetes. Therefore, we identified adiponectin receptors (AdipoRs) as the therapeutic target. It was suggested that, similarly to caloric restriction and exercise, activation of the AdipoRs may have the potential not only to improve lifestyle-related diseases but to contribute to prolonged the shortened lifespan on a high caloric unhealthy diet. To this end, we have identified “AdipoRon” as an adiponectin receptor agonist. Indeed, AdipoRon ameliorated diabetes associated with obesity as well as to increase exercise endurance, thus prolonging shortened lifespan of obese mice fed on a high fat diet. Additionally, we have recently determined the crystal structures of the human AdipoRs. The seven-transmembrane helices of AdipoRs are structurally distinct from those of G-protein coupled receptors. It is expected that these findings will contribute not only to the elucidation of the AdipoR-related signal transduction but to the development and optimization of AdipoR-targeted therapeutics for obesity-related diseases such as diabetes.

Effects of unparticles on top spin correlation at the Large Hadron Collider

Arai, Masato,Okada, Nobuchika,Smolek, Karel American Physical Society 2009 PHYSICAL REVIEW D - Vol.79 No.7

Evaluation of machinability in milling by controlling chip thickness using NC simulation

Makoto Nikawa,Masato Okada,Hiroki Mori,Yasuhiro Fujii,Minoru Yamashita 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

In this study, the machinability of the machining method for controlling chip thickness during the cutting operation was evaluated using simulation based on NC data. A comparative three-dimensional cutting test with a ball end mill was performed using both original and modified NC data. The modified NC data was created for the purpose of controlling the chip thickness generated when cutting with a constant rotation value and changing the feed rate of the original NC data. The results indicated that the actual chip thickness exceeded that of the calculated value although the thickness fluctuation was suppressed. The results revealed that the maximum cutting force and the fluctuation range of cutting force were low, and tool wear after cutting was suppressed using the modified NC data. The application of the method to the cutting of complicated shapes with high removing volume led to reductions in the cutting time by 31 %.

Brief communication : Magnifying Endoscopy for Intestinal Follicular Lymphoma Is Helpful for Prompt Diagnosis

( Masaya Iwamuro ),( Masato Okuda ),( Eiichiro Yumoto ),( Seiyuu Suzuki ),( Atsuko Shirakawa ),( Katsuyoshi Takata ),( Tadashi Yoshino ),( Hiroyuki Okada ),( Kazuhide Yamamoto ) 대한간학회 2013 Gut and Liver Vol.7 No.2

The representative endoscopic features of primary intestinal follicular lymphoma are well known as small whitish polypoid nodules, but a magnified view has only been described in a few case reports. Herein, we report a case with intestinal follicular lymphoma in which magnifying endoscopy with narrow band imaging was helpful for prompt diagnosis. A 57-year-old Japanese woman underwent surveillance esophagogastroduodenoscopy. The endoscopic examination revealed confluent whitish granules in the duodenum, distinct from the nodules or polyps that are typical findings of intestinal follicular lymphoma. Magnifying endoscopy visualized whitish enlarged villi, and narrow band imaging emphasized an elongated and coiled vascular pattern. Based on these features, intestinal follicular lymphoma was highly suspected, and subsequent histological study confirmed the diagnosis. This case demonstrates that magnifying endoscopy with narrow band imaging was useful for the detection and prompt diagnosis of intestinal follicular lymphoma. The pathological features of intestinal follicular lymphoma are also discussed. (Gut Liver 2013;7:258-261)

Distinctive arterial collaterals caused by aortic occlusion in a patient with antiphospholipid syndrome

( Shunya Kaneshita ),( Masei Suda ),( Masato Okada ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.5

Retrograde intrarenal surgery: Past, present, and future

Takaaki Inoue,Shinsuke Okada,Shuzo Hamamoto,Masato Fujisawa 대한비뇨의학회 2021 Investigative and Clinical Urology Vol.62 No.2

With the recent technological advancements in endourology, retrograde intrarenal surgery has become a more popular procedure for treatment of urolithiasis. Furthermore, since the introduction of new laser systems and advanced flexible ureteroscopy with miniaturized ureteroscopes, the treatment indications for retrograde intrarenal surgery have expanded to include not only larger renal stones of >2 cm but also upper urinary tract urothelial carcinoma, ureteral stricture, and idiopathic renal hematuria. Clinicians must keep up with these trends and make good use of these technologies in the rapidly changing field of endourology. Simultaneously, we must consider the risk of various complications including thermal injury due to laser use, ureteral injury caused by the ureteral access sheath, and radiation exposure during retrograde intrarenal surgery with fluoroscopic guidance. This review focuses on the past, present, and future of retrograde intrarenal surgery and provides many topics and clinical options for urologists to consider.

Endomyocardial Biopsy and Magnetic Resonance Imaging of Acute Myocarditis with Adult-Onset Still’s Disease

Masahiro Yamazoe,Atsushi Mizuno,Yasuhiro Suyama,Yutaro Nishi,Koyu Suzuki,Koichiro Niwa,Masato Okada 대한심장학회 2014 Korean Circulation Journal Vol.44 No.6

A 36-year-old female with a high-grade fever and epigastric abdominal pain was prescribed antibiotics, but developed hypoxia and dyspnea. An echocardiography revealed diffuse hypokinesis and massive pericardial effusion, after which diagnostic cardiac catheterizationand an endomyocardial biopsy (EMB) were peformed to reveal fibrosis and infiltration of inflammation cells composed primarily of neutrophils. Clinical manifestation of a spiking fever, leukocytosis, elevated ferritin levels, skin rash and EMB findings led to a diagnosis of adultonsetStill’s disease (AOSD) with acute myocarditis. Pulse therapy of intravenous methylprednisolone was performed for three days, followedby a daily dose of prednisone (60 mg). After a course of steroid therapy for fever and pericardial effusion, and conducting a leftventricular ejection fraction, the patient showed improvement and was discharged asymptomatic within 32 days of admission. This studyis the first to report on a case of myocarditis in AOSD diagnosed by neutrophil infiltration in the myocardium.