Assessment of the Trueness and Inter-Laboratory Precision of Routine Uric Acid Assays Using 4 Frozen Pooled Serum Samples Measured by the Japan Society of Clinical Chemistry’s HPLC Method

Yaping Jiang,Ou Liu,GuoBing Xu 대한진단검사의학회 2014 Annals of Laboratory Medicine Vol.34 No.2

Background: Reference procedures are required for evaluating the accuracy of routine analytical systems for uric acid (UA). External quality assessment (EQA) for UA has only been conducted with quality controls in China, and the results have not been published. This study was designed to investigate both the trueness and inter-laboratory precision of UA measurements among routine analytical systems using a candidate reference method. Methods: We performed the HPLC method recommended by the Japan Society of Clinical Chemistry (JSCC). Next, we evaluated its analytical performance and validated its true- ness. The performance of 4 routine analytical systems (5 instruments per system, n=20) for UA was assessed by using 4 frozen pooled serum samples measured by the HPLC method according to biologically relevant quality goals. Results: Within-run, between-run, inter-day, and total CV of the method were less than 0.3%, 0.4%, 1.8%, and 2.6%, respectively. The UA measurements were consistent with the target values of standard reference material (SRM) 909b, the sixth ring trial for Refer- ence Laboratories (RELA-2008) specimen, and national primary reference materials. The 4 frozen pooled serum samples were homogeneous, stable, and commutable. All routine systems achieved the desirable performance goal (total error <11.9%). Conclusions: We successfully reproduced the JSCC’s HPLC method, which was simple, specific, precise, and accurate. We recommend this method as a reference method for UA measurement in human serum. Four routine analytical systems for UA measurement had acceptable traceability, and their UA results showed good concordance.

Prediction of rolling bearing performance degradation based on sae and TCNattention models

Yaping Wang,Dekang Hou,Di Xu,Sheng Zhang,Chaonan Yang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

A single feature cannot show the operational state of a bearing during its entire life cycle. Therefore, a rolling bearing performance deterioration prediction method based on an SAE and the TCN-attention model is proposed. The SAE method is used to fuse the timedomain indicator and the frequency-domain indicator to construct the performance degradation characteristic indicator. The evaluation indices are used to comprehensively evaluate multiple performance degradation indices, and the fused feature indices together, to filter out the features that have a good overall performance. Attention is added to the TCN model, and the output state weight of the TCN model is calculated through a scoring function to increase the important information weight and the prediction accuracy. The appropriate network structure and parameter configuration are determined, and the rolling bearing performance degradation prediction model is established. A validation is performed using publicly available datasets from the University of Cincinnati and XJTU-SY. The results show that the method is more sensitive to the critical information part of the long time series than the other models. At the same time, the average absolute error and the root mean square error are minimized, the accuracy of the rolling bearing performance degradation prediction is high, and the model has a strong robustness and generalization abilities. Additionally, the model has practical engineering value for predicting the health status of equipment.

One-Step Synthesis and High Electrochemical Performance of Porous Fe3O4/Carbon Nanocomposites as Anodes for Lithium-Ion Batteries

Jianglin Xu,Yaping Zhu,Yan Sun,ANJIAN XIE 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

In this report, the porous Fe3O4/C nanocomposites were successfully synthesized by using ferrocene as raw material and dilute nitric acid as solvent via extremely convenient and low-cost one-step calcining method. The formation of porous structure resulted from the aggregation and assembly of numerous nanoparticles. The experimental results show that the crystallinities, morphologies and electrochemical performance of samples were affected by the calcining temperature and carbon content. As an anode for lithium-ion batteries (LIBs), the Fe3O4/C nanocomposites obtained at calcination temperature of 500 ℃ (Fe3O4/C-a500) exhibited remarkable initial specific discharge capacity of 1418 mA h g -1 and a reversible capacity retention of 721 mA h g -1 after 100 cycles at the current density of 100 mA g -1. The excellent properties can be attributed to the high theoretical capacity of Fe3O4, the high conductivity of carbon and especially the porous structure, which offered more sites for the storage and insertion of Li ions. Even at the current density of 1000 mA h g -1, the reversible capacity of Fe3O4/C-a500 can be up to 291 mA h g -1, indicating the prepared typical nanocomposite presented excellent electrochemical performances and lithium storage capacity, which may be a promising candidate as the anode material for LIBs.

Metal Adsorbate-Induced Plasmon Damping in Gold Nanorods: The Difference Between Metals

Pengyu Xu,Xuxing Lu,Junwei Zhao,Yue Li,Sheng Chen,Junfei Xue,Weihui Ou,Song Han,YAPING DING,Weihai Ni 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.9

We presented a single particle study on the metal adsorbate-induced plasmon damping in Au nanorods (AuNRs) through adsorbing clusters of different metals including Pt, Au and Ag. AuNRs with different longitudinal surface plasmon resonance (LSPR) wavelength were measured and investigated individually. Linewidth broadening, plasmon shift and reduction of plasmonic resonance of single AuNRs were studied and compared between Pt, Au and Ag adsorbates. The measured linewidths perfectly match the theoretical predictions of the billiard model with increased scattering coefficients resulted from the metal adsorbates. The results indicate that the plasmon damping in case of Ag is significantly weaker than Pt and Au, which can be attributed to longer relaxation time of free electrons in Ag and therefore less loss of the oscillating plasmon electrons. In contrast to the red shift observed from Au and Pt, blue shift of the LSPR is observed in case of Ag. It suggests that plasmonic properties brought by the metal adsorbates can exert dramatic influence on the nanoparticle that is adsorbed with. We believe that our study not only provides important understanding on plasmon damping but pave the road for the fabrication of complex nanostructures with two or more metal elements.

The management of hydatidiform mole with lung nodule: a retrospective analysis in 53 patients

Xiao Li,Yaping Xu,Yuanyuan Liu,Xiaodong Cheng,Xinyu Wang,Weiguo Lu,Xing Xie 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.2

Objective: To investigate the significance of lung nodule in hydatidiform mole, we retrospectively compared the clinical outcomes of those patients treated with different strategies. Methods: The patients were divided into three groups: chemotherapy immediately once lung nodule was detected (group 1, n=17), delayed chemotherapy until human chorionic gonadotrophin (hCG) level met the diagnostic criteria for gestational trophoblastic neoplasia (GTN) (group 2, n=18), and hCG surveillance alone until hCG level was normalized spontaneously (group 3, n=18). The clinical parameters of these patients were collected and analyzed. Results: Totally 53 (4.0%) patients were included from 1,323 cases with molar pregnancy during past 16 years. Among them, the diameters of lung nodules were 0.3–2.5 cm. Chemotherapy cycles for achieving hCG normalization and the failure rate of first-line chemotherapy in group 1 were significantly increased than that in group 2 (5 vs. 3 cycles, p=0.000, 58.8% vs. 11.1%, p=0.005). The hCG level of all 18 cases in group 3 was normalized spontaneously within 6 months. Of those, lung nodules of 9 patients disappeared spontaneously, accounting for 25% (9/36) of patients who initially selected observation. The proportion of single nodule in group 3 was significantly higher than that in group 2 (10/18 vs. 2/18, p=0.012). Conclusion: Our results suggest that lung nodule alone is not an adequate indication of chemotherapy in molar pregnancy. hCG surveillance is safe for patients with lung nodule, especially with single nodule, as long as their hCG levels do not meet International Federation of Gynecology and Obstetrics diagnostic criteria for GTN.

Effects of Antioxidant Tempol on Systematic Inflammation and Endothelial Apoptosis in Emphysematous Rats Exposed to Intermittent Hypoxia

Haiyan Zhao,Yaping Zhao,Xin Li,Leiqian Xu,Fangxin Jiang,Wanju Hou,Lixia Dong,Jie Cao 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.9

Purpose: Obstructive sleep apnea and chronic obstructive pulmonary disease are independent risk factors of cardiovascular disease(CVD), and their coexistence is known as overlap syndrome (OS). Endothelial dysfunction is the initial stage of CVD; however,underlying mechanisms linking OS and CVD are not well understood. The aim of this study was to explore whether OS canlead to more severe inflammation and endothelial apoptosis by promoting endothelial dysfunction, and to assess the interventioneffects of antioxidant tempol. Materials and Methods: Male Wistar rats (n=66) were exposed to normal oxygen [normal control (NC) group], intermittent hypoxia(IH group), cigarette smoke (CH group), as well as cigarette smoke and IH (OS group). Tempol intervention was assessed inOS group treated with tempol (OST group) or NaCl (OSN group). After an 8-week challenge, lung tissues, serum, and fresh bloodwere harvested for analysis of endothelial markers and apoptosis. Results: The levels of intracellular adhesion molecule-1, vascular cellular adhesion molecule-1, and apoptosis in circulating epithelialcells were the highest in OS group and the lowest in NC group. These levels were all greater in IH group than in CH group,and were lower in OST group than in OS and OSN groups (all p<0.001). Conclusion: Synergistic effects of IH with cigarette smoke-induced emphysema produce a greater inflammatory status and endothelialapoptosis. OS-related inflammation and endothelial cell apoptosis may play important roles in promoting cardiovasculardysfunction, and antioxidant tempol could achieve a partial protective effect.

A Deep Investigation of the Thermal Decomposition Process of Supported Silver Catalysts

Jiang, Jun,Xu, Tianhao,Li, Yaping,Lei, Xiaodong,Zhang, Hui,Evans, D.G.,Sun, Xiaoming,Duan, Xue Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

A deep understanding of the metallic silver catalysts formation process on oxide support and the formation mechanism is of great scientific and practical meaning for exploring better catalyst preparing procedures. Herein the thermal decomposition process of supported silver catalyst with silver oxalate as the silver precursor in the presence of ethylenediamine and ethanolamine is carefully investigated by employing a variety of characterization techniques including thermal analysis, in situ diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray diffraction. The formation mechanism of supported silver particles was revealed. Results showed that formation of metallic silver begins at about $100^{\circ}C$ and activation process is essentially complete below $145^{\circ}C$. Formation of silver was accompanied by decomposition of oxalate group and removal of organic amines. Catalytic performance tests using the epoxidation of ethylene as a probe reaction showed that rapid activation (for 5 minutes) at a relatively low temperature ($170^{\circ}C$) afforded materials with optimum catalytic performance, since higher activation temperatures and/or longer activation times resulted in sintering of the silver particles.

A Deep Investigation of the Thermal Decomposition Process of Supported Silver Catalysts

Jun Jiang,Tianhao Xu,Yaping Li,Xiaodong Lei,Hui Zhang,D. G. Evans,Xiaoming Sun,Xue Duan 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

A deep understanding of the metallic silver catalysts formation process on oxide support and the formation mechanism is of great scientific and practical meaning for exploring better catalyst preparing procedures. Herein the thermal decomposition process of supported silver catalyst with silver oxalate as the silver precursor in the presence of ethylenediamine and ethanolamine is carefully investigated by employing a variety of characterization techniques including thermal analysis, in situ diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray diffraction. The formation mechanism of supported silver particles was revealed. Results showed that formation of metallic silver begins at about 100 oC and activation process is essentially complete below 145 oC. Formation of silver was accompanied by decomposition of oxalate group and removal of organic amines. Catalytic performance tests using the epoxidation of ethylene as a probe reaction showed that rapid activation (for 5 minutes) at a relatively low temperature (170 oC) afforded materials with optimum catalytic performance, since higher activation temperatures and/or longer activation times resulted in sintering of the silver particles.