Taylor-Couette flow in the narrow-gap limit.

A Cartesian representation of the Taylor-Couette system in the vanishing limit of the gap between coaxial cylinders is presented, where the ratio, [Formula: see text], of the angular velocities, [Formula: see text] and [Formula: see text], of the inner and the outer cylinders, respectively, affects its axisymmetric flow structures. Our numerical stability study finds remarkable agreement with previous studies for the critical Taylor number, [Formula: see text], for the onset of axisymmetric instability. The Taylor number [Formula: see text] can be expressed as [Formula: see text], where [Formula: see text] (the rotation number) and [Formula: see text] (the Reynolds number) in the Cartesian system are related to the average and the difference of [Formula: see text] and [Formula: see text]. The instability sets in the region [Formula: see text], while the product of [Formula: see text] and [Formula: see text] is kept finite. Furthermore, we developed a numerical code to calculate nonlinear axisymmetric flows. It is found that the mean flow distortion of the axisymmetric flow is antisymmetric across the gap when [Formula: see text], while a symmetric part of the mean flow distortion appears additionally when [Formula: see text]. Our analysis also shows that for a finite [Formula: see text] all flows with [Formula: see text] approach the [Formula: see text] axis, so that the plane Couette flow system is recovered in the vanishing gap limit. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (Part 2)'.

[Current Status and Future Prospect of Robotic Gastrectomy for Gastric Cancer].

Robotic gastrectomy had been firstly performed in Japan. The first case series in Japan had been reported by Prof. Uyama of Fujita Medical University in 2011, at which time the double bipolar method, the current standard procedure in Japan, had already been established. Subsequently, a prospective cohort study using laparoscopic gastrectomy as a historical control was conducted under advanced medical care to establish evidence of robotic gastrectomy. As a result, robotic gastrectomy was proven to be safer than laparoscopic gastrectomy, and was approved by health insurance. Furthermore, a survival analysis has showed that overall survival was significantly better in robotic gastrectomy than in laparoscopic gastrectomy, and additional cost for robotic surgery has been covered by insurance. The guidelines of the Japanese Gastric Cancer Association and the Japanese Society for Endoscopic Surgery weakly recommend the use of robotic surgery for cStage Ⅰ or cStage Ⅰ/Ⅱgastric cancer. In order to establish more solid evidence for robotic gastrectomy randomized controlled trials are currently being conducted. Future issues will be the establishment of evidence for robotic surgery and the safe introduction of new robots. Revision of facility standard should also be needed since the number of gastrectomy has been dramatically decreased in Japan.

[The Current Status and Future Perspective about Robotic Surgery for Gastric Cancer].

Robotic surgery using da Vinci®Surgical System which has the high resolution 3-dimensional images, the forceps with 7 degrees freedom, the function for prevention of tremors and motion scaling enables to perform meticulous operation circumventing the action of forceps movement which is the major problem in conventional laparoscopic surgery. In 2003, initial robotic gastrectomy for gastric cancer has been reported. Since then robotic gastrectomy has been developed mainly in Japan, Korea and Italy. From January 2012, we launched robotic gastrectomy at our institute as prospective clinical phase II trials to clarify the safety of robotic gastrectomy. The results of these trials have already been published and the safety of robotic gastrectomy was confirmed. In the several retrospective analyses, robotic gastrectomy has been reported to show longer operation time, less blood loss and lower morbidity compared with conventional laparoscopic surgery. However, the superiority of robotic gastrectomy to laparoscopic gastrectomy has not yet been demonstrated in terms of short- and long-term outcomes in a randomized controlled trial. Since robotic gastrectomy has been approved in Japanese health insurance system at April 2018, it is expected to rapidly expand throughout the country in the near future. Therefore, it is urgent matter to establish an evidence and educational program. In this article, the current status and future perspective about robotic surgery for gastric cancer are presented.

Three-dimensional traveling waves in a square duct.

A nonlinear streamwise traveling-wave solution is obtained by homotopy for square duct flow. For a particular symmetry of the perturbations, this wave comes into existence at about Re(b)=600 (based on half-duct width and bulk speed) for a streamwise wave number alpha=0.85 . The resulting four-vortex mean flow resembles the transitional flow structures observed in previous simulations.

Clinical features and prognoses of 23 patients with chronic granulomatous disease followed for 21 years by a single hospital in Japan.

In this paper, we examined the details of severe infections, treatment efficacies, and the prognoses of 23 Japanese patients with chronic granulomatous disease (CGD). We described the mean ages at diagnosis and follow-up, which were 2.8 years (range, 0.7-10 years) and 14.9 years (range, 0.2-28.4 years), respectively. There were three deaths, two from Aspergillus pneumonia and one from liver abscess. Eighteen of the 23 patients (78%) had a complete loss of gp91phox, and three had p22-phox and one had p67phox deficiencies. Aspergillus species were found in 45% of 174 severe infections. The mean height and weight of the 20 surviving patients were -0.8 +/- 1.3SD and -1.9 +/- 1.9SD below the means for age, respectively. Short stature and underweight (below the 10th percentile of the means) for age were seen in 22% and 17% of the patients, respectively. This growth retardation reflects the severity of the disease. At 20 years of age, there was 87% survival. Ongoing prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) or antifungal drugs was given in 16 and 11 patients, respectively. Interferon-gamma (IFN-gamma) was given once a week to 14 patients. Four patients underwent hematopoietic stem cell transplantation (HSCT) and are currently well. There were infections observed in three of 21 identified related carriers of X-linked CGD. A carrier with a liver abscess had 5% normal neutrophils during the acute phase of infection, which returned to 40% normal neutrophils after recovery. The high survival rate in this hospital results from regular follow-up and prophylaxis with TMP-SMX and anti-fungal drugs beginning at the time of diagnosis, along with treatment with weekly IFN-gamma.

[Plasma creatinine and cystatin C ratio is useful for discriminate diagnosis of postrenal renal failure].

Acute renal failure (ARF) is an acute loss of kidney function that occurs over days to weeks and results in an inability to appropriately excrete nitrogenous wastes and creatinine (Cre). ARF is diagnosed by elevations of blood urea nitrogen and serum Cre level, which is classified as prerenal, intrinsic and postrenal according to their mechanisms. However, discriminate diagnosis of these types by blood biochemistry findings is difficult. Recently, cystatin C (Cys-C), a basic protein having isoelectric point 9.3 with a molecular weight of 13.3 kDa, is freely filtered at the level of the glomerulus and virtually all is reabsorbed and metabolized by the proximal tubular cells. Therefore, assuming constant cellular production, serum Cys-C level has the potential to be an excellent surrogate marker of glomerular filtration rate. Because Cre is electrically charged neutrally, there is a possibility that the permeation of Cys-C, which is positively charged, is diffluent from that of Cre through glomerular basement membrane due to the type of the renal failure. We determined blood concentrations of Cys-C and Cre in a patients with prerenal renal failure (17 patients), intrinsic renal failure (232 patients) and postrenal renal failure (13 patients) as compared with healthy subjects (n = 771). We found that patients with postrenal renal failure displayed significantly elevated Cre/Cys-C ratio (mean +/- standard deviation) (8.3 +/- 8.0, p < 0.001) as compared with healthy subjects (1.1 +/- 0.2), prerenal (0.6 +/- 0.2) and intrinsic (1.6 +/- 0.5). These findings suggest that measurement of Cys-C concentration and Cre/Cys-C ratio may be useful for the discriminate diagnosis of postrenal renal failure.

Transperitoneal rectus sheath block and transversus abdominis plane block for laparoscopic inguinal hernia repair: A novel approach.

INTRODUCTION: A laparoscopic approach for inguinal hernia repair is now considered the gold standard. Laparoscopic surgery is associated with a significant reduction in postoperative pain. Epidural analgesia cannot be used in patients with perioperative anticoagulant therapy because of complications such as epidural hematoma. As such, regional anesthetic techniques, such as ultrasound-guided rectus sheath block and transversus abdominis plane block, have become increasingly popular. However, even these anesthetic techniques have potential complications, such as rectus sheath hematoma, if vessels are damaged. We report the use of a transperitoneal laparoscopic approach for rectus sheath block and transversus abdominis plane block as a novel anesthetic procedure. MATERIAL AND SURGICAL TECHNIQUE: An 81-year-old woman with direct inguinal hernia underwent laparoscopic transabdominal preperitoneal inguinal repair. Epidural anesthesia was not performed because anticoagulant therapy was administered. A Peti-needle™ was delivered through the port, and levobupivacaine was injected though the peritoneum. Surgery was performed successfully, and the anesthetic technique did not affect completion of the operative procedure. The patient was discharged without any complications. DISCUSSION: This technique was feasible, and the procedure was performed safely. Our novel analgesia technique has potential use as a standard postoperative regimen in various laparoscopic surgeries. Additional prospective studies to compare it with other techniques are required.

Focal Segmental Glomerulosclerosis Secondary to Juxtaglomerular Cell Tumor during Pregnancy: A Case Report.

Juxtaglomerular cell tumor is a rare renal neoplasm. Secondary hypertension with juxtaglomerular cell tumor can be seen in females in their 20s and 30s. We present a case of juxtaglomerular cell tumor during pregnancy. A 32-year-old female was hospitalized for refractory hypertension and nephrotic syndrome in the 23rd gestational week. One year before admission, she had been diagnosed with hypertension; plasma renin activity at that time had been 2.3 ng/ml/h. Her blood pressure was uncontrolled during pregnancy, and proteinuria was detected in the 12th gestational week despite the administration of antihypertensive medications. Laboratory data showed proteinuria, hypokalemia, and hypoalbuminemia. In the 25th gestational week, she underwent surgical termination of the pregnancy because of congestive heart failure and acute renal injury. After the termination of the pregnancy and the delivery of a viable fetus, her hypertension and nephrotic syndrome were found to persist with a high plasma renin activity (13 ng/ml/h). Ultrasonography showed a 5.5-cm left renal cystic mass with a partially solid component at the lower renal pole. The left kidney with the renal mass was excised by laparoscopic nephrectomy. Plasma renin activity normalized the next day, with a decrease in blood pressure to 120-130/80-90 mm Hg; however, proteinuria remained at ≥3.5 g/day. On the basis of histopathological findings, the patient was diagnosed with a juxtaglomerular cell tumor and focal segmental glomerulosclerosis. Juxtaglomerular cell tumor is a rare renin-secreting tumor associated with refractory hypertension in young females and is a possible cause of hypertension during pregnancy.