Influence of stator vane number on performance of the axial-flow pump

Can Kang,Xiaojie Yu,Weifeng Gong,Changjiang Li,Qifeng Huang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5

The interplay of impeller and stator is investigated for an axial-flow pump. Three stator vane numbers of 5, 7 and 9 are devised tomatch the same impeller. The renormalization group k-ε turbulence model is used to simulate three-dimensional flows in three pumpswith different vane numbers. Axial velocity distributions at impeller outlet and stator outlet are comparatively analyzed. Experimentsassess operation performance of the three pumps. Vibration parameters and static pressure fluctuations are measured as well. It is indicatedthat the influence of vane number on both pump head and pump efficiency is insignificant. Large stator vane number contributes tothe improvement of the uniformity of axial velocity distribution at impeller outlet. At stator outlet, similar tendency is revealed. Severevibration occurs near the outlet bend of the pump, as is particularly remarkable at vane number of 9. For the three cases, blade passingfrequency and its harmonics are predominant in the frequency spectra of pressure fluctuations. As flow rate increases from 0.8Q to 1.0Q,high-frequency pressure fluctuations are suppressed considerably at vane number of 9, while the other two cases also manifest a declinein overall pressure fluctuation amplitude. The 7-vane case is the most preferable one among the three cases in terms of both pump performanceand pressure fluctuation between the impeller and the stator.

Shen-Kang protects against tacrolimus-induced renal injury

Long Ye Zhang,Jian Jin,Kang Luo,Shang Guo Piao,Hai Lan Zheng,Ji Zhe Jin,임선우,최범순,양철우,Can Li 대한내과학회 2019 The Korean Journal of Internal Medicine Vol.34 No.5

Background/Aims: Evidence suggests that Shen-Kang (SK), a traditional Chinese herbal medicine, protects against various types of renal injury. In this study, we evaluated whether SK treatment confers renoprotection in a rat model of chronic tacrolimus (TAC) nephropathy. Methods: Rats were treated daily with TAC (1.5 mg/kg, subcutaneously) and SK (450 mg/kg, intravenously) for 4 weeks. The effects of SK on TAC-induced renal injury were assessed by measuring renal function, urine albumin excretion, histopathology, inflammatory cell infiltration, expression of profibrotic (transforming growth factor β1 [TGF-β1] and TGF-β inducible gene-h3 [βig-h3]) and proinflammatory cytokines, oxidative stress, and apoptotic cell death. Results: Administration of SK preserved glomerular integrity (fractional mesangial area and Wilms tumor 1-positive glomeruli), attenuated tubulointerstitial fibrosis, and reduced the number of ectodermal dysplasia 1-positive cells, and this was paralleled by improved urine albumin excretion and renal dysfunction. At the molecular level, SK treatment suppressed expression of TGF-β1/Smad2/3, βig-h3, and proinflammatory cytokines. Oxidative stress and apoptotic cell death were significantly decreased with SK treatment, and apoptosis-related genes were regulated toward cell survival (active caspase-3 and the B-cell lymphoma-2/ Bcl2-associated X [Bcl-2/Bax] ratio). Conclusions: SK protects against TAC-induced renal injury.

Combined Effects of Losartan and Pravastatin on Interstitial Inflammation and Fibrosis in Chronic Cyclosporine-Induced Nephropathy

Li, Can,Sun, Bo Kyung,Lim, Sun Woo,Song, Joon Chang,Kang, Shin-Wook,Kim, Yu Seun,Kang, Duk Hee,Cha, Jung Ho,Kim, Jin,Yang, Chul Woo Lippincott Williams Wilkins, Inc. 2005 Transplantation Vol.79 No.11

BACKGROUND.: Statins and angiotensin II type I receptor blockers have synergistic effects on vascular smooth–muscle-cell proliferation and the progression of renal diseases. We evaluated whether combined treatment with losartan (LSRT) and pravastatin (PRVT) affords superior protection compared with their respective monotherapies in treating chronic cyclosporine (CsA)-induced nephropathy in rats. METHODS.: Rats maintained on a low salt diet were given vehicle, CsA (15 mg/kg), CsA and LSRT (10 mg/kg), CsA and PRVT (5 mg/kg), or a combination of CsA, LSRT, and PRVT for 28 days. Basic parameters (renal function, systolic blood pressure, serum high-sensitivity C-reactive protein [hs-CRP], and lipid profiles), histopathology (arteriolopathy, tubulointerstitial fibrosis, and inflammatory cell infiltration), and inflammatory and fibrotic factors (intrarenal CRP, angiotensin II, osteopontin, and transforming growth factor [TGF]-&bgr;1) were studied. RESULTS.: LSRT or PRVT treatment significantly attenuated the histopathologic changes induced by CsA, and combined treatment with LSRT and PRVT further decreased these parameters compared with giving each drug alone. Increased levels of angiotensin II, intrarenal CRP, osteopontin, and TGF-&bgr;1 in CsA-treated rat kidney were reduced by treatment with either LSRT or PRVT and were further decreased by the combination of the two drugs. There were no significant differences in systolic blood pressure or serum lipid parameters between groups. CONCLUSIONS.: Combined treatment with LSRT and PRVT provided synergistic effects in attenuating inflammatory and fibrotic processes in a rat model of chronic CsA-induced nephropathy, and this effect was independent of their hypolipidemic and hypotensive actions.

Ginsengenin derivatives synthesized from 20(R)-panaxotriol: Synthesis, characterization, and antitumor activity targeting HIF-1 pathway

Guo, Hong-Yan,Xing, Yue,Sun, Yu-Qiao,Liu, Can,Xu, Qian,Shang, Fan-Fan,Zhang, Run-Hui,Jin, Xue-Jun,Chen, Fener,Lee, Jung Joon,Kang, Dongzhou,Shen, Qing-Kun,Quan, Zhe-Shan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Ginseng possesses antitumor effects, and ginsenosides are considered to be one of its main active chemical components. Ginsenosides can further be hydrolyzed to generate secondary saponins, and 20(R)-panaxotriol is an important sapogenin of ginsenosides. We aimed to synthesize a new ginsengenin derivative from 20(R)-panaxotriol and investigate its antitumor activity in vivo and in vitro. Methods: Here, 20(R)-panaxotriol was selected as a precursor and was modified into its derivatives. The new products were characterized by ¹H-NMR, ¹³C-NMR and HR-MS and evaluated by molecular docking, MTT, luciferase reporter assay, western blotting, immunofluorescent staining, colony formation assay, EdU labeling and immunofluorescence, apoptosis assay, cells migration assay, transwell assay and in vivo antitumor activity assay. Results: The derivative with the best antitumor activity was identified as 6,12-dihydroxy-4,4,8,10,14-pentamethyl-17-(2,6,6-trimethyltetrahydro-2H-pyran-2-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(tert-butoxycarbonyl)glycinate (A11). The focus of this research was on the antitumor activity of the derivatives. The efficacy of the derivative A11 (IC₅₀ < 0.3 µM) was more than 100 times higher than that of 20(R)- panaxotriol (IC₅₀ > 30 µM). In addition, A11 inhibited the protein expression and nuclear accumulation of the hypoxia-inducible factor HIF-1α in HeLa cells under hypoxic conditions in a dose-dependent manner. Moreover, A11 dose-dependently inhibited the proliferation, migration, and invasion of HeLa cells, while promoting their apoptosis. Notably, the inhibition by A11 was more significant than that by 20(R)-panaxotriol (p < 0.01) in vivo. Conclusion: To our knowledge, this is the first study to report the production of derivative A11 from 20(R)-panaxotriol and its superior antitumor activity compared to its precursor. Moreover, derivative A11 can be used to further study and develop novel antitumor drugs.

Research on the Artificial Neural Network Unfolding Method for the Water-Pumping-Injection Multi-Homocentric Sphere Neutron Spectrometer

Kang Chang,Yi Cheng,Jian-Bo Yang,Yujie Qiao,Rui Li,Can Zhang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.6

This work aimed to study an algorithm for the unfolding spectrum acquired by using a water-pumping-injection multi-homocentric sphere neutron spectrometer. The readings of the water-pumping-injection multi-homocentric sphere neutron spectrometer under 32 different neutron sources, including $^{241}$Am-Be spontaneous, $^{238}$Pu Watt, and $^{232}$Th Maxwell fission, were obtained by using the FLUKA Monte Carlo code and were input as the neural network training values for constructing the method of back-propagation artificial neural network neutron spectrum unfolding (MBANSU). Two neutron readings that were Monte Carlo experimentally measured from $^{252}$Cf spontaneous and $^{245}$Cm Maxwell fission sources were used as the testing values for MBANSU. The calculated neutron energy spectrum was in good agreement with the ENDF energy spectrum, and the information entropy of the result spectrum approximated that of the ENDF spectrum. Results indicate that the established MBANSU algorithm has potential applications for unfolding spectra collected by using the water-pumping-injection multi-homocentric sphere neutron spectrometer.

Effects of operational parameters on performance of the air-powered needle-free injector

Yang Zhu,Can Kang,Wei Cai,Jing Liu,Chao Huang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

The needle-free injection is a new technique for treating subcutaneous drug delivery through penetrating the skin with a high-speed liquid drug jet. The present study aims to reveal fluid dynamics characteristics of the needle-free injection. The operational parameters such as the driving pressure, the nozzle diameter and the liquid volume were investigated for an air-powered needle-free injection system using experimental techniques. The results show that the peak stagnation pressure determines the penetration performance of the jet and is significantly affected by the driving pressure, nozzle diameter and liquid volume. Furthermore, the entire injection process of fluid in the gel can be defined as two phases of penetration and diffusion. Thus, the dispersion characteristics of fluid in different phases could be controlled by an effective combination of the nozzle diameter and liquid volume. Overall, the obtained conclusions provide a sound support for understanding the operation of the needle-free injector.

염소계 VOCs의 UV 광분해 연구

강인선(InSun Kang),Jinying Xi,Can Wang,Hong-Ying Hu 한국대기환경학회 2017 한국대기환경학회지 Vol.33 No.2

Flow Features of a Prefabricated Pumping Station Operating under High Flow Rate Conditions

Qing Li,Can Kang,Mingyi Li 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.2

A prefabricated pumping station catering to the delivery of medium with high flow rate is investigated. Two configurations of storage tanks are devised. Computational fluid dynamics (CFD) is utilized to acquire flow patterns in the pumping station as the pumps operate concurrently. Flow rate allocation and the disturbance of pump operation to ambient medium are depicted. It is demonstrated that both the serial and parallel configurations can fulfill the requirements of high flow rate. Flow rate differs over storage tanks and pumps as well, as is intensified with the serial configuration. The operation of the pumps arouses non-symmetric flow structures in the tank. In comparison, the parallel configuration is desirable in consideration of the uniformity of cross-sectional total pressure and velocity distributions in the outlet pipe of the prefabricated pumping station.

Investigation on the performance and flow characteristics of a liquid lead-bismuth pump

Yongchao Zhang,Can Kang,Yang Zhu,Hyoung Bum Kim 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

The liquid lead-bismuth pump is a core component of the main coolant circuit of the accelerator driven system. The pump performance has a significant effect on the safety and operational stability of the whole system. A liquid lead-bismuth pump was designed and the performance and flow characteristics of the pump were obtained numerically. Effects of transported medium on the performance of the pump and the forces acting on the hydraulic components were investigated. The results show that the operational performance of the pump is improved as the liquid medium of water is replaced with liquid lead-bismuth. The axial force acting on the impeller is dominated by the dynamic reverse force associated with flowing liquid lead-bismuth. Large-scale vortices formed at the bottom of the discharge chamber incur remarkable hydraulic loss. High risk of erosion exists at the outlet part of impeller blades and the inlet part of diffuser blades.

3-Hydroxy-3-methyl glutaryl coenzyme A reductase is required for ovarian development in the oriental fruit fly Bactrocera dorsalis (Hendel)

Wen-Jia Yang,Kang-Kang Xu,Wei Dou,Can Li,JinjunWang 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.3

3-Hydroxy-3-methyl glutaryl coenzyme A reductase (HMGR) is an important rate-limiting enzyme in the mevalonate pathway, which is critical for the synthesis of juvenile hormone and insect development. In this study, a full-length cDNA encoding HMGR (BdHMGR) was cloned from the oriental fruit fly, Bactrocera dorsalis (Hendel). The open reading frame of BdHMGR encoded 928 amino acids and shared a high degree of identity with other known HMGRs. The expression levels of BdHMGR were high during the early and lately pupal stages, and were low at the larval and mid pupal stages. In the adult stages, the highest level of BdHMGR was detected on day-10 of the adult lifecycle, and the expression levels in females were greater than those in males. The highest tissuespecific expression was in the ovary, followed by fat body and other tissues. Injection of double-stranded RNA (dsRNA) of BdHMGR into adult females significantly reduced BdHMGR transcript levels, and inhibited ovarian development and affected the expression of two yolk protein genes. After dissection, we found that one or two of the spheroids of ovaries from the BdHMGR dsRNA-injected flies were amorphous and reduced in size as compared with the controls. The results suggest that BdHMGR is required for ovarian development in B. dorsalis and may be a potential target for pest control.