Study on unsteady tip leakage vortex cavitation in an axial-flow pump using an improved filter-based model

Desheng Zhang,Lei Shi,Ruijie Zhao,Wei-dong Shi,Qiang Pan,B. P. M. (Bart) van Esch 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

The aim of the present investigation is to simulate and analyze the tip leakage flow structure and instantaneous evolution of tip vortex cavitation in a scaled axial-flow pump model. The improved filter-based turbulence model based on the density correction and a homogeneous cavitation model were used for implementing this work. The results show that when entering into the tip clearance, the backward flow separates from the blade tip near the pressure side, resulting in the generation of a corner vortex with high magnitude of turbulence kinetic energy. Then, at the exit of the tip clearance, the leakage jets would re-attach on the blade tip wall. Moreover, the maximum swirling strength method was employed in identifying the TLV core and a counter-rotating induced vortex near the end-wall successfully. The threedimensional cavitation patterns and in-plain cavitation structures obtained by the improved numerical method agree well with the experimental results. At the sheet cavitation trailing edge in the tip region, the perpendicular cavitation cloud induced by TLV sheds and migrates toward the pressure side of the neighboring blade. During its migration, it breaks down abruptly and generates a large number of smallscale cavities, leading to severe degradation of the pump performance, which is similar with the phenomenon observed by Tan et al. [35].

Carpooling Service for Large-Scale Taxicab Networks

Zhang, Desheng,He, Tian,Zhang, Fan,Lu, Mingming,Liu, Yunhuai,Lee, Haengju,Son, Sang H. Association for Computing Machinery 2016 ACM transactions on sensor networks Vol.12 No.3

<P>Carpooling has long held the promise of reducing gas consumption by decreasing mileage to deliver coriders. Although ad hoc carpools already exist in the real world through private arrangements, little research on the topic has been done. In this article, we present the first systematic work to design, implement, and evaluate a carpool service, called coRide, in a large-scale taxicab network intended to reduce total mileage for less gas consumption. Our coRide system consists of three components, a dispatching cloud server, passenger clients, and an onboard customized device, called TaxiBox. In the coRide design, in response to the delivery requests of passengers, dispatching cloud servers calculate cost-efficient carpool routes for taxicab drivers and thus lower fares for the individual passengers. To improve coRide's efficiency in mileage reduction, we formulate an NP-hard route calculation problem under different practical constraints. We then provide (1) an optimal algorithm using Linear Programming, (2) a 2-approximation algorithm with a polynomial complexity, and (3) its corresponding online version with a linear complexity. To encourage coRide's adoption, we present a win-win fare model as the incentive mechanism for passengers and drivers to participate. We test the performance of coRide by a comprehensive evaluation with a real-world trial implementation and a data-driven simulation with 14,000 taxi data from the Chinese city Shenzhen. The results show that compared with the ground truth, our service can reduce 33% of total mileage; with our win-win fare model, we can lower passenger fares by 49% and simultaneously increase driver profit by 76%.</P>

Alternative Biological Material for Tissue Engineering of the Vagina: Porcine-Derived Acellular Vaginal Matrix

Tian Yanpeng,Liu Yibin,Xiao Yanlai,Li Zhongkang,Zhang Mingle,Chen Liang,Li Zhen,Zhang Wangchao,Zhang Zhiqiang,Kong Desheng,Meng Li,Du Yanfang,Zhang Jingkun,Gao Jingui,Huang Xianghua 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.2

Background: Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a severe congenital disorder characterized by vaginal hypoplasia caused by dysplasia of the Müllerian duct. Patients with MRKH syndrome often require nonsurgical or surgical treatment to achieve satisfactory vaginal length and sexual outcomes. The extracellular matrix has been successfully used for vaginal reconstruction. Methods: In this study, we developed a new biological material derived from porcine vagina (acellular vaginal matrix, AVM) to reconstruct the vagina in Bama miniature pigs. The histological characteristics and efficacy of acellularization of AVM were evaluated, and AVM was subsequently transplanted into Bama miniature pigs to reconstruct the vaginas. Results: Macroscopic analysis showed that the neovaginas functioned well in all Bama miniature pigs with AVM implants. Histological analysis and electrophysiological evidence indicated that morphological and functional recovery was restored in normal vaginal tissues. Scanning electron microscopy showed that the neovaginas had mucosal folds characteristics of normal vagina. No significant differences were observed in the expression of CK14, HSP47, and α-actin between the neovaginas and normal vaginal tissues. However, the expression of estrogen receptor (ER) was significantly lower in the neovaginas than in normal vaginal tissues. In addition, AVM promoted the expression of β-catenin, c-Myc, and cyclin D1. These results suggest that AVM might promotes vaginal regeneration by activating the β-catenin/c-Myc/cyclin D1 pathway. Conclusion: This study reveals that porcine-derived AVM has potential application for vaginal regeneration. Background: Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a severe congenital disorder characterized by vaginal hypoplasia caused by dysplasia of the Müllerian duct. Patients with MRKH syndrome often require nonsurgical or surgical treatment to achieve satisfactory vaginal length and sexual outcomes. The extracellular matrix has been successfully used for vaginal reconstruction. Methods: In this study, we developed a new biological material derived from porcine vagina (acellular vaginal matrix, AVM) to reconstruct the vagina in Bama miniature pigs. The histological characteristics and efficacy of acellularization of AVM were evaluated, and AVM was subsequently transplanted into Bama miniature pigs to reconstruct the vaginas. Results: Macroscopic analysis showed that the neovaginas functioned well in all Bama miniature pigs with AVM implants. Histological analysis and electrophysiological evidence indicated that morphological and functional recovery was restored in normal vaginal tissues. Scanning electron microscopy showed that the neovaginas had mucosal folds characteristics of normal vagina. No significant differences were observed in the expression of CK14, HSP47, and α-actin between the neovaginas and normal vaginal tissues. However, the expression of estrogen receptor (ER) was significantly lower in the neovaginas than in normal vaginal tissues. In addition, AVM promoted the expression of β-catenin, c-Myc, and cyclin D1. These results suggest that AVM might promotes vaginal regeneration by activating the β-catenin/c-Myc/cyclin D1 pathway. Conclusion: This study reveals that porcine-derived AVM has potential application for vaginal regeneration.

Comparative study of tip leakage vortex trajectory and cavitation in an axial flow pump with various tip clearances

Xi Shen,Desheng Zhang,Bin Xu,Haoran Wu,Peng Wang,Weidong Shi 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

In order to analyze the effect of blade tip-gap size on the tip leakage vortex (TLV) dynamics and TLV-induced cavitation, a scaled axial flow pump model was created and numerically studied by the combination of an improved SST k-ω turbulence model and a homogeneous cavitation model. The trajectories of TLV core was obtained by using the swirling strength method at different tip-gap sizes vary significantly. The scale of TLV increases as the tip-gap size increases, and the starting point of TLV is sliding further downstream along the blade chord. The angle between the blade suction surface and the TLV also presented an increasing trend with the tip-gap size. The statistics of the velocity normal to the tip chord, as well as the turbulent kinetic energy (KTE) distributions were employed to illustrate a more disordered flow field, which was generated in the tip clearance in a larger amount of leaking flow due to the increased tip-gap size. The in-plain static pressure and vapor volume fraction distributions at different blade chord sections, coupled with three-dimensional cavitation patterns among three tip gaps, are further analyzed to verify the wandering motion of TLV, which shows good agreement with the visualization experiment. Considering the adverse effect of the TLV cavitation, a small tip gap is recommended for improving the axial flow pump performance.

Detection of Spinal Muscular Atrophy Using a Duplexed Real-Time PCR Approach With Locked Nucleic Acid-Modified Primers

Pan Jianyan,Zhang Chunhua,Teng Yanling,Zeng Sijing,Chen Siyi,Liang Desheng,Li Zhuo,Wu Lingqian 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1

Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder mainly caused by homozygous deletions that include exon 7 of the survival motor neuron 1 (SMN1) gene. A nearby paralog gene, SMN2, obstructs the specific detection of SMN1. We optimized a duplexed real-time PCR approach using locked nucleic acid (LNA)-modified primers to specifically detect SMN1. Methods: An LNA-modified primer pair with 3´ ends targeting SMN1 specific sites c.835-44g and c.840C was designed, and its specificity was examined by real-time PCR and Sanger Sequencing. A duplexed real-time PCR approach for amplifying SMN1 and control gene albumin (ALB) was developed. A randomized double-blind trial with 97 fresh peripheral blood samples and 25 dried blood spots (DBS) was conducted to evaluate the clinical efficacy of the duplexed approach. This new approach was then used to screen 753 newborn DBS. Results: The LNA-modified primers exhibited enhanced specificity and 6.8% increased efficiency for SMN1 amplification, compared with conventional primers. After stabilizing the SMN1 test by optimizing the duplexed real-time PCR approach, a clinical trial validated that the sensitivity and specificity of our new approach for detecting SMA patients and carriers was 100%. Using this new approach, 15 of the screened 753 newborns were identified as carriers via DBS, while the rest were identified as normal individuals. These data reveal a carrier rate of 1.99% in Hunan province, South Central China. Conclusions: We have developed a novel, specific SMN1 detection approach utilizing real-time PCR with LNA-modified primers, which could be applied to both prenatal carrier and newborn screening.

A C3 continuous double circumscribed corner rounding method for five-axis linear tool path with improved kinematics performance

Yan Guangwen,Zhang Desheng,Xu Jinting,Sun Yuwen 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.4

Corner rounding methods have been widely developed to pursue the smooth motions of machine tools. However, most corner rounding methods, which adopt the double inscribed transitions, still remain an inherent issue of retaining large curvatures of transition curves. Even for those double circumscribed transitions-based methods with relatively small curvatures, they also constrain excessively the transition lengths and are limited to a low-order continuity, deteriorating the feedrate and jerk of machine tools. For addressing these problems, a C3 continuous double circumscribed corner rounding (DCCR) method is proposed for five-axis linear tool path. In this method, the C3 continuous double circumscribed B-splines are specially designed to round the corners of tool position and tool orientation, whose transition lengths are analytically determined by jointly constraining the approximation errors, overlaps elimination, and parameter synchronization. Moreover, the excessive constrains of transition lengths imposed by traditional methods are alleviated by fully considering the effects of overlaps and parameter synchronization, and the jerk of rotary axes is also limited with a high-order continuity. Compared to the existing double inscribed corner rounding (DICR) and DCCR methods, experiment results demonstrate that our method can improve further the feedrate while limiting the jerk of machine tools.

PERFORMANCE ANALYSIS OF A NOVEL SELF-EXCITED, LIQUID-COOLED, AND BRIDGE INTEGRATED ELECTROMAGNETIC RETARDER FOR HEAVY VEHICLES WITH TRAILER

Wenguang Guo,Desheng Li,Lezhi Ye,Zhiwei Gao,Kai Zhang 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.5

To overcome the large power consumption, the braking torque heat recession, and installation difficulties for trailers of eddy current retarder (ECR), a novel self-excited, liquid-cooled, and bridge integrated retarder (SLB-EMR) is proposed in this paper. The structure and work principle of the SLB-EMR are described particularly. Based on the magnetic equivalent circuit (MEC) method, an analytical model of the eddy current braking torque considering magnetic flux leakage and end effect is established. The power generation and braking performance of the SLB-EMR are predicted by the finite element analysis (FEA). We carried out tests for the eddy current braking torque, the heat-fade of braking torque, the no-load loss torque, and natural characteristics of the SLB-EMR respectively. The test results showed that the eddy current braking torque reached 2592 N·m at 1000 r/min. The braking torque declined by 15.5 % after the braking 12 min continuously. The analytical model of eddy current braking torque, and FEA model of the generator and eddy current brake were verified by the test. Compared with the ECR, the SLB-EMR had no-power consumption and low head-fade.

FOXK1 regulates epithelial-mesenchymal transition and radiation sensitivity in nasopharyngeal carcinoma via the JAK/STAT3 signaling pathway

Duan Liqun,Huang Jinlong,Zhang Yong,Pi Guoliang,Ying Xiaofang,Zeng Fanyu,Hu Desheng,Ma Jia 한국유전학회 2023 Genes & Genomics Vol.45 No.6

Background Nasopharyngeal carcinoma (NPC) is the most common head and neck tumor in China. Forkhead box (FOX) proteins have 19 subfamilies, which can maintain cell metabolism, regulate cell cycle and cell growth, etc. FOXK1 is a member of the FOX family, and studies have found that FOXK1 is closely related to tumors. Objective This experiment aims to study the effects of FOXK1 interference on proliferation, apoptosis, invasion, epithelial-mesenchymal transition (EMT), and radiosensitivity, by regulating the Janus kinas/signal translator and activator of the transfer 3 (JAK/STAT3) pathway. Methods The expression of FOXK1 was detected via immunohistochemistry using clinical nasopharyngeal carcinoma tissues and adjacent tissues. The relationship between FOXK1 expression and tumor stage was subsequently evaluated. The colony formation rate was calculated through the colony formation experiment. Cell apoptosis and cell cycle distribution were detected using flow cytometry, while cell invasion was detected using the Transwell method. The number of cells in the nucleus of each group after 30 min, 4 h, and 24 h of radiotherapy with the 2 Gy dose was counted using immunofluorescence under γ-H2AX focal points of a laser confocal microscope. Results FOXK1 is clearly expressed in the patients’ cancer tissues. The expression of FOXK1 was significantly correlated with the patient’s sex. FOXK1 interference or Peficitinib can upregulate the apoptosis rate of 5-8 F and CNE-2 cells; increase the G2 phase of cells; and inhibit the invasion, migration, and EMT of cells. At the same time, FOXK1 interference can downregulate the protein expression of p-JAK1, p-JAK2, and p-STAT3 in cells. Interference from FOXK1 or Peficitinib alone can reduce the rate of cell colony formation under different radiation doses, and enhance the green fluorescence intensity of γ-H2AX in the nucleus after 4 and 24 h of the 2 Gy dose of radiotherapy. These results are optimal when FOXK1 interference and Peficitinib are used together. Conclusion FOXK1 interference in NPC cells can regulate EMT through the JAK/STAT3 signal pathway, enhance the radiosensitivity of cells, and thus inhibit tumor cell progression.

Genistein inhibit the proliferation induced by zearalenone in MCF-7 cells

Wang, Dingfa,Ma, Qingshan,Zhang, Niya,Qi, Desheng The Korean Society of Toxicogenomics and Toxicopro 2010 Molecular & cellular toxicology Vol.6 No.1

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin and exists widely in the moldy feeds and food. Genistein (GEN) is a natural isoflavone phytoestrogen. ZEA has adverse effects on animal's reproduction performance and immunologic function, also can induce the proliferation of MCF-7 cells. However, the interactive effect of ZEA and GEN on proliferation and cell cycle in MCF-7 cells is remain poorly understood. Here, the interactive effect of ZEA and GEN on proliferation and cell cycle in MCF-7 cells were determined through MTT assay and flow cytometry, respectively. Results demonstrated that ZEA(10 and 20 nM) could stimulate the proliferation of MCF-7 cells and significantly increase S phase distribution (P< 0.05). RT-PCR analysis revealed that ZEA could significantly increase estrogen receptor (ER) $\alpha$ mRNA expression (P < 0.05), while GEN (16 and $32\;{\mu}M$) could inhibit proliferation and lessen S phase distribution of MCF-7 cells (P < 0.05) which were induced by ZEA. In the co-administration treatments of GEN and ZEA, $ER\alpha$ mRNA expression decreased, bcl-2 decreased and bax increased at both mRNA and protein levels compared to those with ZEA alone. These results showed that the proliferative activity of ZEA could be repressed by GEN through regulating the expression of ER, bax and bcl-2 in MCF-7 cells.

Catalytic synthesis and enhanced Curie temperature of ε-Fe₃N@C nanostructure synthesized in a tetraethylenepentamine solution

Li, Yong,Pan, Desheng,Li, Da,Feng, Yang,Choi, C.J.,Liu, Wei,Zhang, Zhidong Elsevier 2018 Journal of magnetism and magnetic materials Vol.465 No.-

<P><B>Abstract</B></P> <P>ε-Fe<SUB>3</SUB>N@C nanocrystals without oxidation are one-pot synthesized by using the iron(II) acetylacetonate and tetraethylenepentamine (TEPA) as Fe and N precursors under a low temperature (533 K) in the presence of a small quantity of Pt atoms as the co-catalyst. The ε-Fe<SUB>3</SUB>N@C nanoparticles with a core-shell structure are nearly spherical and have a wide particle size distribution of 100–500 nm in diameter. Fe nanoparticles obtained by reduction of Fe<SUP>2+</SUP> with TEPA are an effective catalyzer for decomposing TEPA to produce N and C atoms at a temperature much lower than the boiling point of TEPA. The diffusion of N atoms into Fe nanoparticles for the formation of ε-Fe<SUB>3</SUB>N@C is proposed, based on the results obtained by kinetically controlling the synthetic temperature and surfactants. The ε-Fe<SUB>3</SUB>N@C nanoparticles have an excellent saturation magnetization of 135.5 emu/g at room temperature. A significantly enhanced Curie temperature (T<SUB>C</SUB>) of 614 K is reached in the present ε-Fe<SUB>3</SUB>N@C nanoparticles, which is much higher than the T<SUB>C</SUB> values in the previously reported ε-Fe<SUB>3</SUB>N<SUB>x</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Tetraethylenepentamine is proposed as a new N source to synthesize Fe nitride. </LI> <LI> Core-shelled ε-Fe<SUB>3</SUB>N@C nanoparticles are one-pot synthesized at 260 °C. </LI> <LI> Curie temperature of ε-Fe<SUB>3</SUB>N is significantly enhanced to 614 K. </LI> <LI> ε-Fe<SUB>3</SUB>N@C shows a high saturation magnetization of 135.5 emu/g at 300 K. </LI> </UL> </P>