Search

Background: High-risk non-muscle invasive bladder cancer (NMIBC) is thought to be associated with a higher risk of recurrence and progression. A recent study revealed that a high De Ritis ratio was a risk factor in some solid malignancies. This study examined the importance of the De Ritis ratio as a prognostic marker in high-risk NMIBC. Materials and Methods: A total of 138 patients who were initially diagnosed with high-risk NMIBC between January 2012 to December 2016 were enrolled in this study. The criteria for the high-risk classification followed the EAU guidelines. The recurrence-free and progression-free survival of the higher and lower De Ritis ratio groups were compared. The cut-off value of the De Ritis ratio was set at 1.35, based on a receiver operator curve analysis. Results: The median observation period was 50.3 months. Among these patients, 32 (23.1%) patients developed recurrent disease and 15 (10.9%) patients showed progression. A multivariate analysis revealed that non-BCG treatment was an independent risk factor for recurrence, and a higher De Ritis ratio was an independent risk factor for cancer progression. Conclusions: The De Ritis ratio might be a risk factor for progression in high-risk NMIBC.

Malignant peritoneal mesothelioma is generally characterized by chief complaints such as abdominal mass and abdominal pain. We report a case of malignant peritoneal mesothelioma diagnosed as an inguinal mass. A 69-year-old man was referred to our hospital complaining of abdominal distension and swelling in the right inguinal region. Abdominal/pelvic contrast-enhanced computed tomography revealed a 22 cm tumor from the right inguinal canal to the peritoneal cavity and a large amount of ascites. Because imaging analyses revealed no metastasis, we planned tumor resection. We resected the tumor with the peritoneum and right testis and sampled some nodules in the mesentery. Histopathological examination of the tumor led to the diagnosis of epithelial malignant mesothelioma. Adhering to chemotherapy guidelines for pleural malignant mesothelioma, six courses of pemetrexed and cisplatin combination chemotherapy were performed. He is alive with no evidence of new local tumor or nodules in the mesentery 1 year postoperatively.

In recent times, interior permanent magnet synchronous motors (IPMSMs) with high efficiency have been used in various applications. However, IPMSMs generate torque ripple and acoustic noise due to a radial electromagnetic force. In particular, the acoustic noise needs to be suppressed in applications where low noise levels are required. In this paper, the suppression of the 6th‐ and 12th-order radial electromagnetic forces, which contribute significantly to acoustic noise, is discussed. The relationship among the armature current, the permanent magnet of the rotor, and the radial electromagnetic force of the IPMSM is clarified. Moreover, the compensation current required to suppress the 6th‐ and 12th-order radial electromagnetic forces is derived. In addition, a method to suppress the 6th‐ and 12th-order radial electromagnetic forces is proposed through the feedforward addition of the compensation voltage calculated from the compensation current to the voltage command of the drive system based on a sinusoidal current tracking control. By setting the gain of the sinusoidal current tracking control as low as possible, the voltage command produced by the current control system is maintained low, and a margin is provided for adding a compensation voltage to suppress the radial electromagnetic forces. The effectiveness of the proposed feedforward voltage compensation method is verified by the results of frequency analysis of the sound produced by an IPMSM. In addition, the superiority of the proposed sinusoidal current tracking control is confirmed by comparison with the frequency analysis of the sound produced by a $d-q$ axis current controlled motor.

To determine the effects of long-range transport of aerosols from an upwind area in East Asia to a downwind area in Japan, we chemically analyzed aerosols collected simultaneously on Tuoji Island (Shandong Province, China), Fukue Island (Nagasaki Prefecture, Japan), and Cape Hedo (Okinawa Prefecture, Japan). We focused on changes in the metallic composition of PM2.5 aerosols during long-range transport. The average mass concentrations of PM2.5 at the three sites decreased in the order Tuoji Island > Fukue Island ≈ Cape Hedo (48.3 ± 4.5, 13.9 ± 1.5, and 13.2 ± 0.9 μg/m3, respectively). The fraction of coarse particles in total suspended particles estimated by (1–PM2.5/TSP) was highest on Cape Hedo, indicating that the contribution of sea salts was increased by long-range transport of the aerosols over the ocean. Enrichment factor analysis revealed that at all three sites, Al, K, Ca, Mn, Fe, Co, Sr, and Ba originated from soil; whereas Cr, Ni, Cu, Zn, As, Mo, Ag, Cd, Sn, Sb, Tl, and P appeared to be of anthropogenic origin. Na was the most abundant element on Cape Hedo, indicating the addition of sea salts during aerosol transport. The V concentration was highest at Fukue Island, which was ascribed to V emission from ships. Sixty-one percent of the V on Fukue Island and 62% of the V on Cape Hedo were determined to have originated from ships, implicating of data obtained on dates during which backward trajectory analysis indicated that the same air mass passed over Tuoji Island, Fukue Island, and Cape Hedo in that order.

Hypogenesis or agenesis of right hepatic lobe is a rare abnormality and is generally associated with gallbladder and biliary tract abnormalities. Cases of biliary injury following cholecystectomy have been reported in patients with agenesis of right hepatic lobe because the anatomical anomalies complicate the surgical approach. We report a case of laparoscopic cholecystectomy in a patient with hypogenesis of right hepatic lobe. A 92-year-old male patient was admitted to our hospital with fever and right lower abdominal pain with suspected acute appendicitis. Abdominal computed tomography revealed gallstones with acute cholecystitis and hypogenesis of right hepatic lobe. He underwent laparoscopic cholecystectomy with the left semilateral decubitus position. The patient's postoperative course was uneventful. In conclusions, some patients with liver lobe hypoplasia do not present with the typical symptoms of acute cholecystitis due to dislocation of the gallbladder. The left semilateral decubitus position with modified placement of port sites is useful for laparoscopic cholecystectomy in patients with hypogenesis of right hepatic lobe.

In the electrolytic capacitorless inverter system, resonance occurs between the inductance on the grid side and the DC-link capacitor. Because of this resonance, the regulation of the input current harmonic may not be satisfied in some cases. In order to satisfy harmonic regulation, a method for controlling this input current by direct DC-link current control has been proposed using PWM modulation. In PWM modulation, the switching frequency depends on the carrier frequency. This paper proposes a control method that reduces the switching frequency and satisfies the harmonic regulation via model predictive direct current control (MPDCC). This paper is confirmed that the proposed method reduces harmonics of input current and switching frequency. The effectiveness of the proposed method is verified by numerical simulation.

SUMMARY This paper describes a soft-switching interleaved power factor correction (PFC) converter with a lossless snubber. AC–DC converters require a unity input power factor characteristic with highly efficient operation to prevent the inflow of harmonic current to the power source. The proposed PFC converter improves the input current ripple with interleave control. The converter realizes a high efficiency by the soft-switching operation of all switching devices without a large auxiliary resonant circuit. This paper introduces the soft-switching operation of the converter. In order to confirm the validity of the proposed converter, experiments with a prototype of the PFC converter have been performed. The experimental results indicate that the proposed converter can realize the soft-switching operation of all switching devices, a reduction in the input current ripple, a unity power factor of 98% or more, a sinusoidal input current, and constant output voltage control. The efficiency of the proposed PFC converter with a lossless snubber is higher than that without the lossless snubber. The results presented in this paper confirm the validity of the proposed converter.