Nikkiso (Japan)

Cavitation is not only a cause of decreased suction performance of centrifugal pumps, but also a source of noise, so it requires suitable handling. In a previous study, noise, and cavitation in a centrifugal pump with low solidity inducer were experimentally analyzed to clarify the relationship. However, it is not clear whether a specific trend exists between pump operation and noise, even for more complex internal flows, since the blades of this inducer have a simple, nearly flat shape. In this study, a centrifugal pump with a low solidity fan type inducer with blades composed of multiple airfoils was used as a test model. Experiments were conducted using the pump to measure pump performance and noise under various pump operating conditions, including cavitating conditions. In addition, paint erosion tests were conducted under each operating condition to investigate the area where cavitation bubbles collapse on the inducer blade, which is one of the causes of the noise. The analysis of these results showed that specific trends exist between pump operation and noise, even when an inducer with complex geometry is attached.

The purpose of this review is to summarize the status of wire arc additive manufacturing (WAAM) in industrial parts and identify future research topics. First, a literature review of the results of studies on WAAM for industrial parts was conducted to summarize the current literature. Based on the study results obtained through the literature review, the main current issues are summarized. It was found that studies on WAAM have been conducted for a variety of industries, but not for all industries where arc welding, the basis of WAAM, is used. In addition, many studies have been conducted on steel, whereas no studies have been conducted on titanium or multi-materials. The study concluded that an effective means of expanding the industrial use of WAAM is to treat the uncovered topics.

The influence of inducer blades’ geometry on the propagation of cavitation instabilities was examined using three and four-bladed inducer, to develop the design criteria that can operate stably over a wide operation range. In industrial centrifugal pumps used for transporting liquefied natural gas at low flow rates and low NPSH, the self-excited oscillations caused by cavitation have been observed. In previous studies, both the effect of the number of inducer blades on pump performance and the effect of the blades’ outlet angle on cavitation instability phenomena were investigated. The main objective of this study was to investigate the effect of the configuration of blade number and outlet angle on the suppression of cavitation instability phenomena at low flow rates.

An evaluation was conducted on the fabrication of an axial flow impeller by a hybrid system of wire arc additive manufacturing and machining. First, a four-bladed stainless steel axial flow impeller was fabricated to measure the number of chips and fabrication time. Next, axial flow impellers with different numbers of blades were designed and compared with those fabricated only by machining from a round bar. In both cases, the number of chips was reduced by approximately 80% by using this system. On the other hand, the increase in the number of blades reduced the difference in fabrication time, which was almost the same with six blades. In conclusion, the use of this system is an option from the viewpoint of reducing environmental impact; however, it is not necessarily advantageous in terms of fabrication time.

The role of the kidney as an excretory organ for exogenous and endogenous compounds is well recognized, but there is a wealth of data demonstrating that the kidney has significant metabolizing capacity for a variety of exogenous and endogenous compounds that in some cases surpass the liver. The induction of drug-metabolizing enzymes by some chemicals can cause drug-drug interactions and intraindividual variability in drug clearance. In this study, we evaluated the expression and induction of cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) isoforms in 3D-cultured primary human renal proximal tubule epithelial cells (RPTEC) to elucidate their utility as models of renal drug metabolism. CYP2B6, CYP2E1, CYP3A4, CYP3A5, and all detected UGTs (UGT1A1, UGT1A4, UGT1A6, UGT1A9, and UGT2B7) mRNA levels in 3D-RPTEC were significantly higher than those in 2D-RPTEC and HK-2 cells and were close to the levels in the human kidney cortex. CYP1B1 and CYP2J2 mRNA levels in 3D-RPTEC were comparable to those in 2D-RPTEC, HK-2 cells, and the human kidney cortex. Midazolam 1'-hydroxylation, trifluoperazine N-glucuronidation, serotonin O-glucuronidation, propofol O-glucuronidation, and morphine 3-glucuronidation in the 3D-RPTEC were significantly higher than the 2D-RPTEC and comparable to those in the HepaRG cells, although bupropion, ebastine, and calcitriol hydroxylations were not different between the 2D- and 3D-RPTEC. Treatment with ligands of the aryl hydrocarbon receptor and farnesoid X receptor induced CYP1A1 and UGT2B4 expression, respectively, in 3D-RPTEC compared with 2D-RPTEC. We provided information on the expression, activity, and induction abilities of P450s and UGTs in 3D-RPTEC as an in vitro human renal metabolism model. SIGNIFICANCE STATEMENT: This study demonstrated that the expression of cytochrome P450s (P450s) and UDP-glucuronosyltransferases (UGTs) in 3D-cultured primary human renal proximal tubule epithelial cells (3D-RPTEC) was higher than those in 2D-cultured primary human renal proximal tubule epithelial cells and HK-2 cells. The results were comparable to that in the human kidney cortex. 3D-RPTEC are useful for evaluating the induction of kidney P450s, UDP-glucuronosyltransferases, and human renal drug metabolism in cellulo.

For designing and evaluating the dialyzer and investigating the optimal therapeutic conditions, in vitro studies bring us many useful findings. In hemodialysis, however, the membrane fouling due to protein molecules reduces solute removal performance. Therefore, we investigated a method for replicating the fouling in dialyzers in aqueous experiments. After the albumin solution was circulated in the test circuit with a dialyzer, a glutaraldehyde solution was pumped into the dialyzer to immobilize albumin on the hollow fiber membrane. Under various immobilization conditions, the permeability of creatinine and vitamin B12 was evaluated by dialysis experiments. The creatinine clearance after immobilization of albumin was decreased, suggesting pore plugging by our fouling replication method. The glutaraldehyde crosslinked albumin molecules that adhered them to the membrane firmly. Moreover, the degree of fouling may be controlled by changing the concentration of albumin solution and the volume of glutaraldehyde solution used for immobilization. Our fouling replication method was applied to three types of polyester polymer alloy (PEPA) dialyzers and one polysulfone (PSf) dialyzer. This method enables to evaluate the permeability of various dialyzers with fouling in vitro that will be of great help in collecting data for designing dialyzers.

To determine the prevalence of sleep-related disorders, poor sleeping, and factors associated with poor sleep quality among inhabitants of Parakou, Benin. This was a cross-sectional study conducted from April-August 2018on 930 randomly selected adults (age ≥ 18 years). Using the Pittsburg Sleep Quality Index, the Insomnia Severity Index, and the EpworthSleepiness Scale, subjects were questioned on their sleep, on parasomnias, and onmovement-related sleep disorders. Overall, the prevalence of insomnia was 22% (95% CI, 19.1-24.4) and severe insomnia was 0.8%. The prevalence of excessive daytime sleepiness was 15% (95% CI, 12.5-17.0). Daily nightmares (2%) and rhythmic movements (6%) were those most commonly reported among parasomnias and movement-related sleep disorders. No major differences were found between men and women. The prevalence of poor sleeping (PSQI > 5) was 39% (95%CI, 36.3-42.5). Adjusted analyses showed a higher risk of poor sleeping in those aged 45-54 years (aOR = 1.78, p = 0.032) or ≥ 55 years (aOR = 3.61, p < 0.001), those overweight or obese (aOR = 1.53, p = 0.007), those underweight (aOR = 2.90, p = 0.030), and among females (aOR = 1.84, p < 0.001). Being divorced was associated with a lower risk of poor sleeping (aOR = 0.18, p = 0.036). Poor sleepers were more commonly found among those who had excessive daytime sleepiness (65% versus 36%, p < 0.001) and insomnia (86% versus 27%, p < 0.001). Sleep-related disorders were common in Parakou city, Benin, with four out of ten persons having poor sleep quality. There is a need to improve the management of sleep-related disorders and promote better sleep practices for the community.

Recently, intensive care physicians have focused on continuous hemodiafiltration with a cytokine-adsorbing hemofilter in the treatment of sepsis. We aimed to establish extracorporeal circulation in a rat sepsis model to evaluate the cytokine removal properties of mini-modules using two types of membrane materials. Rats were divided into polyester polymer alloy (PEPA) and cellulose triacetate (CTA) groups as membrane materials of mini-modules. One hour after 0.1mg/kg of lipopolysaccharide administration, continuous hemofiltration (CHF) was started in each group. Plasma interleukin-6 (IL-6), an important mediator of sepsis, was measured over time during hemofiltration. The peak IL-6 concentration in PEPA group was approximately 13,000pg/mL, in comparison to approximately 31,000pg/mL in CTA group. IL-6 clearance in PEPA group was much more than CTA group. Since IL-6 was not detected in the filtrate in PEPA group, it was considered that IL-6 was adsorbed to the membrane. In conclusion, our results suggest that CHF with PEPA hemofilter can be suitable for removing IL-6 from the blood stream efficiently.