An Accurate Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide and Its Use in Harmonization in China

Deng Yuhang,Zhang Chao,Wang Jing,Zeng Jie,Zhang Jiangtao,Zhang Tianjiao,Zhao Haijian,Zhou Weiyan,Zhang Chuanbao 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.4

Background: Serum C-peptide results from various routine methods used in China are highly variable, warranting well-performing methods to serve as an accuracy base to improve the harmonization of C-peptide measurements in China. We developed an accurate isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC–MS/MS) method for serum C-peptide measurement and explored its use in harmonization. Methods: After protein precipitation with ZnSO4 solution, C-peptide was extracted from serum samples by anion-exchange solid-phase extraction and quantified by ID-LC–MS/MS in positive ion mode. The precision and analytical recovery of the ID-LC–MS/MS method were assessed. Seventy-six serum samples were analyzed using the ID-LC–MS/MS method and six routine immunoassays. Ordinary linear regression (OLR) and Bland-Altman (BA) analyses were conducted to evaluate the relationship between the ID-LC–MS/MS method and routine immunoassays. Five serum pool samples assigned using the ID-LC–MS/MS method were used to recalibrate the routine assays. OLR and BA analyses were re-conducted after recalibration. Results: The within-run, between-run, and total precision for the ID-LC–MS/MS method at four concentrations were 1.0%–2.1%, 0.6%–1.2%, and 1.3%–2.2%, respectively. The analytical recoveries for the ID-LC–MS/MS method at three concentrations were 100.3%–100.7%, 100.4%–101.0%, and 99.6%–100.7%. The developed method and the immunoassays were strongly correlated, with all R2 >0.98. The comparability among the immunoassays was substantially improved after recalibration. Conclusions: The performance of the ID-LC–MS/MS method was carefully validated, and this method can be used to improve the harmonization of serum C-peptide measurements in China.

Photosensitive Al2O3 slurry with high solid content and low viscosity

Zhang Xu,Zhang Jingde,Tian Yuhang,Xiao Shikang,Li Jianzhang,Han Guifang 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3

Slurries with high solid content and low viscosity are highly necessary to lower the sintering shrinkage and avoid possible defects for ceramic components fabricated by vat photopolymerization technique. However, the viscosity of slurry dramati- cally arises with the increase of solid content, which severely affects the printing process and the quality of preformance. To solve this issue, a novel combined strategy of powder surface modification and selection of dispersant was proposed to significantly increase the solid load without too much increase in viscosity. The surface of Al 2O3 particles was modified by Silane A174 to improve its wettability with resins, and then the use of KOS 110 formed steric hindrance between particles achieving good dispersion. The synergistic effect of the modifier and dispersant was realized. Al 2O3 slurry with a high solid loading up to 65 vol% and low viscosity of 20.0 Pa·s at 30  s −1 was prepared for stereolithography-based DLP 3D printing, which had among the highest performance in photosensitive Al 2O3 slurries.

Modification on SAGD CPF Via Energy Integration

( Zhang Yuhang ),강춘형 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Process Integration (PI) is widespread used in various industries to help enhance energy efficiency and increase profitability. Pinch analysis is one of the most well-known PI approach which emerged in the last 20 years and has been developing so far. This paper explored modifications of heat exchanger networks in the SAGD oil sands extraction central process facilities by using pinch analysis. The retrofit resulted in 14.07% utilities saving. This corresponds to investment reduction of 12.18%.

Analysis of nonlinear vibration response of a functionally graded truncated conical shell with piezoelectric layers

Yuhang Zhang,Wenguang Liu,Zhipeng Lyu,Chao Liu,Lei Pang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

The nonlinear vibration response of a functionally graded materials (FGMs) truncated conical shell with piezoelectric layers is analyzed. The vibration amplitude is suppressed by the positive and inverse piezoelectric effects. And the bifurcation phenomenon is described to reveal the motion state of the conical shell. Firstly, a truncated conical shell composed of three layers is described. And the effective material properties of the FG layer are defined by the Voigt model and the power law distribution. Next, the electric potentials of piezoelectric layers are defined as cosine distribution along the thickness direction. Meanwhile, the constant gain negative velocity feedback algorithm is used to suppress the vibration amplitude by the electric potential produced by the sensor layer. Thereafter, considering the first-order shear deformation theory and the von Karman nonlinearity, the relationship between the strain and displacement is defined. And the corresponding energy of the conical shell is calculated. After that, the motion equations of the conical shell are derived based on the Hamilton principle. Again, the nonlinear single degree of freedom equation is derived by the Galerkin method and the static condensation method. In the end, the nonlinear vibration response of FGMs truncated conical shell with piezoelectric layers under the external excitation is analyzed via using the harmonic balance method and the Runge-Kutta method. The effects of various parameters, such as ceramic volume fraction exponent, external excitation’s amplitude, control gain and geometric parameters on the nonlinear vibration response of the system are evaluated by case studies. Results indicate that the control gain plays an important role on the suppression of the vibration amplitude. The ceramic volume fraction exponents are not sensitive to the nonlinear vibration response compared with other parameters. The bifurcation behavior is observed under different parameters. The FGMs truncated conical shell with piezoelectric layers has three types of motion state, such as periodic motion, multi-periodic motion, and chaos motion.

Compound control strategy for maximum power point tracking with flexible step-up converters for thin film photovoltaic module applications

Liu, Yuhang,Liu, Xiangxin,Zhang, Jianwei,Zhang, Yufeng,Liu, Guangchen The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.9

This paper proposes a novel maximum power point tracking (MPPT) algorithm for a thin-film photovoltaic (PV) module with a flexible step-up DC-DC converter. To improve the voltage rating for the thin film module, a switch-inductor zero voltage transition (SIZVT) boost converter is proposed. In addition, the proposed methodology uses a multistage variable step size (MVSS) with a power close-loop control strategy (PCLC) for MPPT. The corresponding performances are compared with the classical fixed step size (FSS) algorithm and the conventional variable step size (CVSS) algorithm. Simulation results in MATLAB/Simulink and experimental tests with a 240 W prototype validate the proposed algorithm under a variety of conditions.

Direct observation of the hysteretic Fermi level modulation in monolayer MoS2 field effect transistors

Yuhang Wang,Dongyong Li,Xubo Lai,Boyang Liu,Yibao Chen,Fengping Wang,Rongming Wang,Liuwan Zhang 한국물리학회 2020 Current Applied Physics Vol.20 No.2

The hysteresis in the transfer curve of MoS2 has significant impact on the device performance. However, the hysteresis mechanism is still not clear. Here, we investigate the hysteresis of the monolayer MoS2 by probing the local Fermi level variations as a function of the back gate voltage in different atmosphere using the Kelvin probe microscopy. While the Fermi level of the MoS2 in air is much lower than that in vacuum, both the MoS2 devices in vacuum and air show large Fermi level hysteresis. The Fermi level hysteresis direction is clock-wise, identical to that observed in the transfer curves. Both the hysteresis in Fermi level and transfer curve can be explained consistently by taking into account the charge trapping. Our findings confirm that carrier density modulation in MoS2 plays a vital role in the hysteresis, and provide insight into the hysteresis mechanism for the optimization of the device performance.

SET/PP2A signaling regulates macrophage positioning in hypoxic tumor regions by amplifying chemotactic responses

Zhang Shaolong,Zhou Jingping,Shang Pengzhao,Zhao Guomeng,Wang Anlei,Mao Jinlei,Tao Yuhang,Chen Ziyi,Wang Xuehao,Guo Changying 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Tumor-associated macrophages (TAMs) are one of the main cellular components in the tumor microenvironment (TME). In many types of solid tumors, TAMs tend to accumulate in hypoxic areas and are intimately related to poor patient prognosis. However, the underlying mechanisms by which TAMs infiltrate hypoxic tumor regions remain unclear. In this study, we report that genetic deletion of SE translocation (SET) in myeloid cells inhibited the entry of TAMs into the hypoxic tumor region and abated their proangiogenic and immunosuppressive functions, ultimately inhibiting tumor growth. Mechanistically, in response to hypoxic tumor supernatant stimulation, SET in macrophages shuttled between the nucleus and cytoplasm via the PKC-CK2α signaling axis. Cytoplasmic retention of SET increased ERK and P38 signaling by inhibiting PP2A, which promoted TAM migration into the hypoxic area and polarization toward the M2 phenotype. Therefore, we conclude that SET modulates tumor immunity by acting as a key regulator of macrophage positioning and function in the tumor.

Quantitative Characterization Method for Rock Surface Roughness with Different Scale Fluctuation

Yuhang Guo,Chuanqing Zhang,Hang Xiang,Guojian Cui,Fanzhen Meng,Hui Zhou 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.4

Quantitative characterization of the surface roughness plays a vital role in the field of rock mechanics. The objectives of this study were to propose a new index that can describe the various morphological characteristics with different scale fluctuation. The power spectral density (PSD) parameters and conventional statistical parameters were used to analyze the roughness of meso-scale grind surfaces, intermediate-scale synthesis surfaces, and macro-scale shear surfaces. The results showed that the PSD parameters (slope k, intercept b, spectral moment λ0, and spectral shape parameters ω1 and ω2) and conventional statistical parameters(RMS and Z2) have evident uniqueness and uniformity in characterizing the roughness with different scale fluctuation. It is necessary to appropriately use the correct parameters for classifying and quantifying the roughness. For this purpose, a new characterization index SLAwas proposed based on the spectral shape parameter ω1, spectral moment λ0, slope k, and angle fractal index C.

Commutability Assessment of Processed Human Plasma Samples for Normetanephrine and Metanephrine Measurements Based on the Candidate Reference Measurement Procedure

Deng Yuhang,Liu Qingxiang,Liu Zhenni,Zhao Haijian,Zhou Weiyan,Zhang Chuanbao 대한진단검사의학회 2022 Annals of Laboratory Medicine Vol.42 No.5

Background: To identify candidate external quality assessment (EQA) materials for normetanephrine and metanephrine measurements, we assessed the commutability of eight processed human plasma samples. The agreement between routine assays and the candidate reference measurement procedure (cRMP) was also evaluated. Methods: Fifty-three clinical samples and eight processed plasma samples were prepared. The processed samples included pooled and individual plasma samples spiked with pure normetanephrine and metanephrine and non-spiked pooled and individual plasma samples. The clinical and processed samples were subjected to four routine isotope dilution tandem mass spectrometry assays and cRMP. Commutability was assessed based on two approaches recommended by the CLSI and International Federation of Clinical Chemistry (IFCC). Passing–Bablok regression and Bland–Altman analysis were used to evaluate the agreement between the routine assays and cRMP. Results: The commutability results of the CLSI approach were better than those of the IFCC approach. For the CLSI approach, spiked individual plasma samples and spiked high-concentration pooled plasma samples were commutable for all routine assays for both analytes. The non-spiked pooled plasma sample was commutable for two out of four routine assays for metanephrine and three out of four routine assays for normetanephrine. The agreement between the routine assays and the cRMP was satisfactory, except for one routine assay showing significant bias. Conclusions: High-concentration spiked pooled plasma samples and spiked individual plasma samples are candidate EQA materials for normetanephrine and metanephrine measurements.

In Situ Formation of Pt–Au Nanoparticles on Magnetic Composites Carriers: Tuning Catalytic Activity by Incorporation of Different Metal Oxides

Zewu Zhang,Qiong Wu,Xiaohai Bu,Zusheng Hang,Zhangzhong Wang,Qikang Wang,Yuhang Ma 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.1

Supported Pt─Au bimetal nanocatalysts have been prepared by an in situ reduction method followed by calcination in air and reduction in H2 atmosphere. The catalysts exhibit a typical yolk-shell construction composed of a moveable magnetic Fe core and metal oxides shells decorated with Pt─Au nanoparticles. The structure of the bimetal nanocatalysts was characterized in detail by TEM, XRD, XPS, and N2 physical adsorption and the catalytic activity of the nanocatalysts was studied by the catalytic reduction of 4-nitrophenol to 4-nitrophenol. It is found that the bimetal nanocatalysts composed with the different metallic oxides (TiO2 and ZrO2) exhibited the comparable Pt─Au particles size (~10 nm). However, the content of Pt─Au nanoparticles was varied with the metallic oxides support. Pt─Au nanoparticles deposited uniformly on TiO2 with higher loadings, however the nanoparticles on ZrO2 exhibited remarkably lower content, which should be attributed to the abundant hydroxyl on TiO2 surface that served as the deposition site for Pt─Au nanoparticles. The result of the reduction reaction indicated that incorporation of TiO2 in the bimetal Pt─Au nanocatalyst could significantly improve the catalytic activity as compared with ZrO2 and m-SiO2. A possible mechanism was proposed to explain the synergistic effect in the supported Pt─Au bimetal nanocatalysts.