Modified Wettability of Micro-structured Steel Surfaces Fabricated by Elliptical Vibration Diamond Cutting

Jianguo Zhang,Andreas Rosenkranz,Junjie Zhang,Jiang Guo,Xiaoqing Li,Xiao Chen,Junfeng Xiao,Jianfeng Xu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.5

Hardened steel is an important material related to the development of modern industry branches. In order to satisfy the adhesion strength as well as the corrosion and wear resistance under extreme conditions, the modification of the wettability of hardened steel has become an important scientific topic. As micro/nano-structured surfaces play an essential role to induce advanced functional surfaces with wettability control, this contribution aims at presenting the feasibility of micro/nano sculpturing of hardened steels by elliptical vibration diamond cutting. The influence of the fabricated micro/nano structures on the resulting wettability is discussed and related to the contact line density as well as asperity heights. In this regard, it has been verified that a pitch value of 12 μm and structural height of 500 nm are the preferred structural parameters to increase the hydrophobicity of the textured steel specimens.

Attitude Control Design for Hypersonic Reentry Vehicles Subject to Control Direction Reversal via Sliding Mode Approach

Yixin Ding,Zongyi Guo,Yonglin Han,Jiaqi Wang,Jianguo Guo,Zequn Liu,Jinlong Zhao 한국항공우주학회 2024 International Journal of Aeronautical and Space Sc Vol.25 No.2

This paper investigates the control direction reversal issue for the attitude control design for hypersonic reentry vehicles, and proposes a novel sliding mode control law which addresses the control direction switching and strong robustness requirement simultaneously. Firstly, the disturbance observer is introduced to estimate the unmatched uncertainties in the attitude model of hypersonic reentry vehicles, and then a periodic function-involved sliding mode control is presented and the bounded stability of the closed-loop system is guaranteed via Lyapunov stability theory. The merits of the proposed method lie in that the closed-loop system is stable even under the unknown control direction reversal, and the unmatched uncertainties can be addressed by the disturbance observer. Finally, the simulation verifies the effectiveness and superiority of the proposed control.

Detection of Myocardial Metabolic Abnormalities by 18F-FDG PET/CT and Corresponding Pathological Changes in Beagles with Local Heart Irradiation

Rui Yan,Jianbo Song,Zhifang Wu,Min Guo,Jianzhong Liu,Jianguo Li,Xinzhong Hao,Sijin Li 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.4

To determine the efficacy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the detection of radiation-induced myocardial damage in beagles by comparing two pre-scan preparation protocols as well as to determine the correlation between abnormal myocardial FDG uptake and pathological findings. The anterior myocardium of 12 beagles received radiotherapy locally with a single X-ray dose of 20 Gy. 18F-FDG cardiac PET/CT was performed at baseline and 3 months after radiation. Twelve beagles underwent two protocols before PET/CT: 12 hours of fasting (12H-F), 12H-F followed by a high-fat diet (F-HFD). Regions of interest were drawn on the irradiation and the non-irradiation fields to obtain their maximal standardized uptake values (SUVmax). Then the ratio of the SUV of the irradiation to the non-irradiation fields (INR) was computed. Histopathological changes were identified by light and electron microscopy. Using the 12H-F protocol, the average INRs were 1.18 ± 0.10 and 1.41 ± 0.18 before and after irradiation, respectively (p = 0.021). Using the F-HFD protocol, the average INRs were 0.99 ± 0.15 and 2.54 ± 0.43, respectively (p < 0.001). High FDG uptake in irradiation field was detected in 33.3% (4/12) of 12H-F protocol and 83.3% (10/12) of F-HFD protocol in visual analysis, respectively (p = 0.031). The pathology of the irradiated myocardium showed obvious perivascular fibrosis and changes in mitochondrial vacuoles. High FDG uptake in an irradiated field may be related with radiation-induced myocardial damage resulting from microvascular damage and mitochondrial injury. An F-HFD preparation protocol used before obtaining PET/CT can improve the sensitivity of the detection of cardiotoxicity associated with radiotherapy.

Osteogenic effect of magnesium oxychloride cement modified with phytic acid and loaded with strontium ranelate

Tingting Ma,Yijia Guan,Jinlun Feng,Yue Yang,Junying Chen,Wenjie Guo,Jianguo Liao,Yanru Zhang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Magnesium oxychloride cement has good mechanical properties, but poor water resistance. Methods Phytic acid, which can form chelate with Mg2+, was used to modify magnesium oxychloride cement, and the effects of phytic acid on the strength, in vitro degradation and biological activity of magnesium oxychloride cement were studied. Based on the preparation of phytic acid modified magnesium oxychloride cement with good water resistance and biological activity, osteoporosis treatment strontium ranelate was loaded on phytic acidmagnesium oxychloride cement, strontium ranelate/phytic acid-magnesium oxychloride cement was prepared. Results It was found that the compressive strength of 1.25 wt% phytic acid-magnesium oxychloride cement after soaking in SBF for 28 d could reach 40.5 ± 2.0 MPa, 13.33% higher than that of the control group (when phytic acid was 0 wt%), and the mass loss rate of all ages was lower than that of the control group. The water resistance of magnesium oxychloride cement was effectively improved by phytic acid. After loading with strontium ranelate, the water resistance of 1.25 wt% phytic acid-magnesium oxychloride cement was improved. Cell experiments showed that strontium ranelate could effectively promote cell proliferation and improve the expression of osteoblastrelated proteins. When strontium ranelate/phytic acid-magnesium oxychloride cement samples were implanted subcutaneously in rats for 4 w, no obvious inflammatory response was observed, and the material was tightly bound to the surrounding tissues. When bone cement was implanted into rat femur for 4 w, the bone cement was gradually wrapped and absorbed by new bone tissue, which grew from the outside to the inside, indicating that the bone cement containing strontium ranelate/phytic acid-magnesium oxychloride cement had excellent bone-forming ability. Conclusions In conclusion, the results indicated that strontium ranelate/phytic acid-magnesium oxychloride cement composite bone cement had a potential application prospect in clinical bone repair.

Use of Long-chain Alcohol in Extraction and Purification of Lincomycin from Fermentation Broth

Wu, Bin,Zhu, Jiawen,Chen, Kui,Ji, Lijun,Guo, Jianguo,Zhao, Jianxi 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.2

Low selectivity for lincomycin in butanol extraction process leads to relatively higher content of impurities. A novel process for extraction of lincomycin from fermentation broth was studied in this work. Mixture of n-octanol and n-decanol is used as extractant to replace n-butanol in extraction of lincomycin. Oprimal operation conditions for the process have been studied. Due to higher extraction selectivity for lincomycin A by long-chain alcohol, content of impurity(lincomycin B) in the final product is much lower than that in product by butanol process. Furthemore, the practicability for combination of long-chain alcohol and butanol in purification of linecomycin was investigated.

Design and analysis of mechanical flux‑weakening device of axial flux permanent magnet machines

Shaopeng Wang,Jiawei Lu,Bin Li,Chengcheng Liu,Youhua Wang,Gang Lei,Youguang Guo,Jianguo Zhu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

Due to the low inductance of an axial flux permanent magnet machine (AFPMM), the constant power speed regulation range is small. A new mechanical flux-weakening method for single-rotor single-stator AFPMMs is proposed in this paper. By installing a mechanical flux-weakening device on one side of the stator and rotating it certain angle, the speed regulation of the flux-weakening can be realized. The device is simple in structure, easy to operate, and can be operated in the process of machine operation. The validity of the device is verified by applying it to a machine. Finite-element software is used to calculate and analyze the performances of two machines with the device.

A prospective randomized multicenter trial for lymphadenectomy in early- stage ovarian cancer: LOVE study

Ting Deng,Kaijiang Liu,Liang Chen,Xiao-jun Chen,Hua Wen Li,Hongyan Guo,Huijiao Zhang,Libing Xiang,Xin Feng,Xiaoyu Wang,Hextan Y. S. Ngan,Jianguo Zhao,Dongling Zou,Qing Liu,Jihong Liu 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.3

Background: The Lymphadenectomy in Ovarian Neoplasms (LION) study revealed that systemic lymphadenectomy did not bring survival benefit for advanced ovarian cancer patients with clinically normal lymph nodes and was associated with a higher incidence of operative complications. However, there is no consensus on whether lymphadenectomy has survival benefit or not in early epithelial ovarian cancer (EOC). Methods: We designed the LOVE study, a multicenter, randomized controlled, phase III trial to compare the efficacy and safety of comprehensive staging surgery with or without lymphadenectomy in stages IA-IIB EOC and fallopian tube carcinomas (FTC). The hypothesis is that the oncological outcomes provided by comprehensive staging surgery without lymphadenectomy are non-inferior to those of conventional completion staging surgery in early-stage EOC and FTC patients who have indications for post-operative adjuvant chemotherapy. Patients assigned to experimental group will undergo comprehensive staging surgery, but lymphadenectomy. Patients assigned to comparative group will undergo completion staging surgery including systematic pelvic and para-aortic lymphadenectomy. All subjects will receive 3–6 cycles of standard adjuvant chemotherapy. Major inclusion criteria are pathologic confirmed stage IA-IIB EOC or FTC, and patients have indications for adjuvant chemotherapy either confirmed by intraoperative fast frozen section or previous pathology after an incomplete staging surgery. Major exclusion criteria are non-epithelial tumors and low-grade serous carcinoma. Patients with severe rectum involvement which lead to partial rectum resection will be excluded. The sample size is 656 subjects. Primary endpoint is disease-free survival.

Applications of carbon-based materials in solid phase micro-extraction: a review

Jian Guo,Soo-Jin Park,Long-Yue Meng,Xinghua Jin 한국탄소학회 2017 Carbon Letters Vol.24 No.-

Static aerodynamic force coefficients for an arch bridge girder with two cross section

Jian Guo,Minjun Zhua 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.31 No.3

Aiming at the wind-resistant design of a sea-crossing arch bridge, the static aerodynamic coefficients of its girder (composed of stretches of π-shaped cross-section and box cross-section) were studied by using computational fluid dynamics (CFD) numerical simulation and wind tunnel test. Based on the comparison between numerical simulation, wind tunnel test and specification recommendation, a combined calculation method for the horizontal force coefficient of intermediate and small span bridges is proposed. The results show that the two-dimensional CFD numerical simulations of the individual cross sections are sufficient to meet the accuracy requirements of engineering practice.

Tristetraprolin Overexpression in Gastric Cancer Cells Suppresses PD-L1 Expression and Inhibits Tumor Progression by Enhancing Antitumor Immunity

Jian Guo,Huiheng Qu,Ting Shan,Yigang Chen,Ye Chen,Jiazeng Xia 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.7

The RNA-binding protein tristetraprolin (TTP) binds to adenosine- uridine AU-rich elements in the 3’-untranslated region of messenger RNAs and facilitates rapid degradation of the target mRNAs. Therefore, it regulates the expression of multiple cancer and immunity-associated transcripts. Furthermore, a lack of TTP in cancer cells influences cancer progression and predicts poor survival. Although the functions of TTP on cancer cells have previously been researched, the mechanism of TTP on the interaction between cancer cells with their microenvironment remains undiscovered. In this study, we admed to determine the role of cancer cell TTP during the interaction between tumor and immune cells, specifically regulatory T cells (Tregs). We evaluate the capability of TTP to modulate the antitumor immunity of GC and explored the underlying mechanism. The overexpression of TTP in GC cells dramatically increased peripheral blood mononuclear lymphocyte (PBML) -mediated cytotoxicity against GC cells. Increased cytotoxicity against TTP-overexpressed GC cells by PBMLs was determined by Treg development and infiltration. Surprisingly, we found the stabilization of programmed death-ligand 1 (PD-L1) mRNA was declining while TTP was elevated. The PDL1 protein level was reduced in TTP-abundant GC cells. PD-L1 gas been found to play a pivotal role in Treg development and functional maintenance in immune system. Taken together, our results suggest the overexpression of TTP in GC cells not only affects cell survival and apoptosis but also increases PBMLs -mediated cytotoxicity against GC cells to decelerate tumor progression. Moreover, we identified PD-L1 as a critical TTP-regulated factor that contributes to inhibiting antitumor immunity.