Timelike surfaces of constant mean curvature 1 in anti-de Sitter 3-space

It is shown that timelike surfaces of constant mean curvature 1 in anti-de Sitter 3-space can be constructed from a pair of Lorentz holomorphic and Lorentz antiholomorphic null curves in PSL(2,R) via Bryant type representation formulae. These formulae are used to investigate an explicit one-to-one correspondence, the so-called Lawson correspondence, between timelike surfaces of constant mean curvature 1 in anti-de Sitter 3-space and timelike minimal surfaces in Minkowski 3-space. The hyperbolic Gauss map of timelike surfaces in anti-de Sitter 3-space, which is a close analogue of the classical Gauss map is considered. It is discussed that the hyperbolic Gauss map plays an important role in the study of timelike surfaces of constant mean curvature 1 in anti-de Sitter 3-space. In particular, the relationship between the Lorentz holomorphicity of the hyperbolic Gauss map and timelike surfaces of constant mean curvature 1 in anti-de Sitter 3-space is studied.Comment: 47 pages, 24 figures, references revised, Annals of Global Analysis and Geometr

Cyclical and Patch-Like GDNF Distribution along the Basal Surface of Sertoli Cells in Mouse and Hamster Testes

BACKGROUND AND AIMS: In mammalian spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) is one of the major Sertoli cell-derived factors which regulates the maintenance of undifferentiated spermatogonia including spermatogonial stem cells (SSCs) through GDNF family receptor α1 (GFRα1). It remains unclear as to when, where and how GDNF molecules are produced and exposed to the GFRα1-positive spermatogonia in vivo. METHODOLOGY AND PRINCIPAL FINDINGS: Here we show the cyclical and patch-like distribution of immunoreactive GDNF-positive signals and their close co-localization with a subpopulation of GFRα1-positive spermatogonia along the basal surface of Sertoli cells in mice and hamsters. Anti-GDNF section immunostaining revealed that GDNF-positive signals are mainly cytoplasmic and observed specifically in the Sertoli cells in a species-specific as well as a seminiferous cycle- and spermatogenic activity-dependent manner. In contrast to the ubiquitous GDNF signals in mouse testes, high levels of its signals were cyclically observed in hamster testes prior to spermiation. Whole-mount anti-GDNF staining of the seminiferous tubules successfully visualized the cyclical and patch-like extracellular distribution of GDNF-positive granular deposits along the basal surface of Sertoli cells in both species. Double-staining of GDNF and GFRα1 demonstrated the close co-localization of GDNF deposits and a subpopulation of GFRα1-positive spermatogonia. In both species, GFRα1-positive cells showed a slender bipolar shape as well as a tendency for increased cell numbers in the GDNF-enriched area, as compared with those in the GDNF-low/negative area of the seminiferous tubules. CONCLUSION/SIGNIFICANCE: Our data provide direct evidence of regionally defined patch-like GDNF-positive signal site in which GFRα1-positive spermatogonia possibly interact with GDNF in the basal compartment of the seminiferous tubules

Modern management for brain metastasis patients using stereotactic radiosurgery: literature review and the authors’ gamma knife treatment experiences

Yoshinori Higuchi,1,* Masaaki Yamamoto,2,* Toru Serizawa,3 Hitoshi Aiyama,2 Yasunori Sato,4 Bierta E Barfod2 1Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba, Japan; 2Katsuta Hospital Mito Gamma House, Hitachi-Naka, Japan; 3Tokyo Gamma Unit Center, Tsukiji Neurological Clinic, Tokyo, Japan; 4Department of Global Clinical Research, Chiba University Graduate School of Medicine, Chiba, Japan *These authors contributed equally to this work Abstract: Historically, whole brain radiotherapy was administered to most patients with brain metastases. However, over the past three decades, stereotactic radiosurgery (SRS), targeted at individual cranial lesions, has been accepted widely. In this study, based on the authors’ experiences along with published data, recent trends in SRS for brain metastases are discussed. This article focuses on the following issues: 1) How many tumors can or should be treated with SRS? 2) Two-/three-staged SRS for relatively large tumors, 3) post- or preoperative SRS, and 4) repeat SRS. Keywords: brain metastases, radiotherapy, radiosurgery, gamma knif

Impact of technically qualified surgeons on laparoscopic colorectal resection outcomes : results of a propensity score-matching analysis

Background The Endoscopic Surgical Skill Qualification System (ESSQS) was introduced in Japan to improve the quality of laparoscopic surgery. This cohort study investigated the short- and long-term postoperative outcomes of colorectal cancer laparoscopic procedures performed by or with qualified surgeons compared with outcomes for unqualified surgeons. Methods All laparoscopic colorectal resections performed from 2010 to 2013 in 11 Japanese hospitals were reviewed retrospectively. The procedures were categorized as performed by surgeons with or without the ESSQS qualification and patients' clinical, pathological and surgical features were used to match subgroups using propensity scoring. Outcome measures included postoperative and long-term results. Results Overall, 1428 procedures were analysed; 586 procedures were performed with ESSQS-qualified surgeons and 842 were done by ESSQS-unqualified surgeons. Upon matching, two cohorts of 426 patients were selected for comparison of short-term results. A prevalence of rectal resection (50.3 versus 40.5 per cent; P < 0.001) and shorter duration of surgery (230 versus 238 min; P = 0.045) was reported for the ESSQS group. Intraoperative and postoperative complication and reoperation rates were significantly lower in the ESSQS group than in the non-ESSQS group (1.2 versus 3.6 per cent, P = 0.014; 4.6 versus 7.5 per cent, P = 0.025; 1.9 versus 3.9 per cent, P = 0.023, respectively). These findings were confirmed after propensity score matching. Cox regression analysis found that non-attendance of ESSQS-qualified surgeons (hazard ratio 12.30, 95 per cent c.i. 1.28 to 119.10; P = 0.038) was independently associated with local recurrence in patients with stage II disease. Conclusion Laparoscopic colorectal procedures performed with ESSQS-qualified surgeons showed improved postoperative results. Further studies are needed to investigate the impact of the qualification on long-term oncological outcomes

A Fundamental Study on the Effect of Visual Guidance to Inspectors Using Visual Indicator on Defect Detection in Visual Inspection Utilizing Peripheral Vision

Part 7: Industry 4.0 – Collaborative Cyber-physical Production and Human SystemsInternational audienceIn recent years, it is reported that a number of inspectors in the visual inspection process of industrial products utilized not only the central vision but also the peripheral vision. The visual inspection has been realized with both efficiency and accuracy. However, for the inspectors of many manufacturing industries to adopt this method, visual guidance is necessary for visual attention. Therefore, to obtain the fundamental knowledge for training of the visual inspection method, this study considers the effect of visual guidance on the defect detection performed by inspectors using visual indicators. Specifically, the presence or absence of visual guidance, defect location, and defect characteristics (luminance contrast between defect and inspection model and size) are designed as experimental factors. Further, the effect on inspection accuracy is evaluated with six subjects. As a result, it is clarified that the presence or absence of visual guidance does not affect the defect detection regardless of the defect location and defect characteristics. That is, the visual guidance is not an impediment to inspection accuracy; it is suggested that the visual guidance is an effective tool for the education and training of the visual inspection method utilizing peripheral vision