Search Results

You are looking at 11 - 20 of 21 items for

  • Author or Editor: Yun Wang x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

The hydrogenation of biomass-derived ethyl lactate was studied over several ruthenium catalysts (Ru/TiO2, Ru/SiO2, Ru/γ-Al2O3, Ru/NaY and Ru/C), with the intent of developing a simple and additive-free catalytic system. The catalytic performance is dependent on the nature of the support. Ru/SiO2 was found to be an efficient catalyst for the hydrogenation of ethyl lactate to 1,2-propanediol (1,2-PDO). Parametric studies show that the reaction temperature, hydrogen pressure and catalyst amount can significantly influence the catalytic performance. Under optimal reaction conditions (433 K, 5 MPa), high yield of 1,2-PDO (82.1%) was obtained without the introduction of any additives. Form a practical point of view, this study may open the way to a new approach for the production of 1,2-PDO.

Restricted access

Scutellaria barbata D. Don has been used as a traditional Chinese medicine for antitumor and anti-inflammatory. However, there were just a few investigations about S. barbata D. Don according to bioactivity-directed isolation and online identification for the chemical constituents. In this work, eight compounds were isolated from S. barbata D. Don. The three flavonoids indicated the cytotoxic activity against human leukemic Reh cell lines. In addition, the constituents of S. barbata D. Don were further characterized and identified by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). The UHPLC- Q-TOF-MS method was in negative ion mode. HPLC separation was performed on a Tosoh TSK gel ODS-100V (4.6 × 150 mm, 3.0 μm) column by gradient elution using water containing 0.3% formic acid and acetonitrile as mobile phase at a flow rate of 0.8 mL min−1. A total of 18 compounds, including 4 phenolic acids and 14 flavonoids were tentatively characterized and identified by means of the retention time, accurate mass, and characteristic fragment ions.

Open access

Abstract  

A chemical process for the separation of147Nd/147Pm from fission products of synthetic radioactive waste solution has been developed. The process includes: (1) denitration, (2) removal of high concentration of uranium by 30% TBP/kerosene extraction, (3) removal of95Nb,103Ru,137Cs and part of90Sr by 50% TBP/dodecane extraction, (4) separation of147Nd/147Pm from part of90Sr and95Zr by oxalic acid precipitation, and (5) removal of144Ce by mixture of 0.4M D2EHPA and 0.2M TBP extraction. Experimental results indicate that the recovery of147Nd/147Pm in the final separated solution is about 90%. The purification of147Nd and147Pm from some other rare earth elements, viz.153Sm,154Eu and144Ce was further investigated by using a Dowex 50W×8 ion-exchanger. Parameters of flow rate, eluent concentration and pH were examined. The results show that the recovery and radionuclide purity of147Nd plus147Pm under the present separation conditions are 77.8% and 98.6% for diethylenetriaminepentaacetic acid (DTPA) and 87.3% and 99.5% for nitrilotriacetic acid (NTA), respectively.

Restricted access

Abstract

Background and aims

Previous research has established risk factors for problematic smartphone use (PSU), but few studies to date have explored the structure of PSU symptoms. This study capitalizes on network analysis to identify the core symptoms of PSU in a large sample of students.

Methods

This research investigated 26,950 grade 4 students (male = 13,271) and 11,687 grade 8 students (male = 5,739) using the smartphone addiction proneness scale (SAPS). The collected data were analyzed using a network analysis method, which can provide centrality indexes to determine the core symptoms of PSU. The two networks from the different groups were compared using a permutation test.

Results

The results indicated that the core symptoms of students' problematic smartphone use were the loss of control and continued excessive use across the two samples.

Discussion and conclusions

These findings suggest that loss of control is a key feature of problematic smartphone use. The results also provide some evidence relevant to previous research from the perspective of network analysis and some suggestions for future treatment or prevention of students' problematic smartphone use.

Open access
Acta Chromatographica
Authors: Yun Wang, Jianhong Chen, Yutian Li, Puling Li, Javed Iqbal, Ying Chen, Yinlian Ma, and Cun Zhang

A reliable and rapid high-performance liquid chromatography coupled with diode array detector method (HPLC–DAD) was established and validated to determine eight gingerol simultaneously in the rhizomes of Zingiber offcinale Rosc. The separation of eight compounds (4-hydroxy-3-methoxy-benzenebutanol,3,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl) decane, 3,5-dihydroxy-1-(3,4-dimethoxyphenyl) decane, 6-gingerol, 8-gingerol, 6-shogaol, 5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1,4-decadien-3-one, and 10-gingerol) were performed on an Agilent TC(2) C18 (250 mm × 4.6 mm, 5 μm) at 30 °C using acetonitrile (A) and 1% formic acid aqueous solution (B) as the mobile phase with gradient elution (0–10 min, 20%–35% A; 10–28 min, 35%–55% A; 28–35 min, 55%–60% A; 35–55 min, 60%–70% A; 55.01–60 min, 100%–100% A). The detection wavelength was set at 280 nm, and the flow rate was 0.8 mL/min. Validation of the analytical method was performed by linearity, precision, and accuracy test. All compounds were quantified with good linear calibration curves (coefficient of determination R 2, >0.9999). The method showed good precision with overall coefficients of variation between 0.56% and 0.84%. The range of recovery was from 95.50% to 104.14% for the analytes. This method was successfully applied to quantify eight gingerols in Z. offcinale Rosc from different regions in China, so it can provide quality assessment for this medicine.

Open access

Abstract

Background and aims

To understand the interaction between problematic smartphone use (PSU) and related influencing factors (individual variables, family environment, and school environment) and to determine the most influential factors affecting the use of smartphones by juveniles to implement effective interventions in the future.

Methods

A total of 3,442 children and adolescents (3,248 actual participants (males = 1,638, average age = 12.27 ± 2.36)) were included in the study. This study measured juveniles’ PSU and its influencing factors: individual variables (4 factors), family environments (13 factors), and school environments (5 factors). This study employed a network analysis approach for data assessment.

Results

This study found that there were several central influencing factors (such as self-control ability, loss of control, parent-child relationship, and peer attitudes towards smartphone use) and bridge factors (such as peer attitudes towards smartphone use, peer pressure for smartphone use, and fear of missing out).

Discussion and conclusions

Juveniles’ PSU included several core symptoms and critical influencing factors. Intervention based on these factors may be effective, timely, and inexpensive.

Open access
Journal of Radioanalytical and Nuclear Chemistry
Authors: Huan Meng, Zhen Chen, Gengmei Xing, Hui Yuan, Chunying Chen, Feng Zhao, Chengcheng Zhang, Yun Wang, and Yuliang Zhao

Abstract  

Recently, it was reported that the toxicity of copper particles increases with the decrease of the particle size on a mass basis. To understand this phenomenon, inductively coupled plasma mass spectrometry (ICP-MS) techniques and in vitro chemical studies were carried out to explore how they produce toxicity in vivo. The results suggest that when the sizes of particles become small and down to a nanoscale, copper becomes extremely reactive in a simulative intracorporeal environment. The nanosized copper particles consume the hydrogen ions in stomach more quickly than micron ones. These processes further convert the copper nanoparticles into cupric ions whose toxicity is very high in vivo.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: Zhen Chen, Huan Meng, Hui Yuan, Gengmei Xing, Chunying Chen, Feng Zhao, Yun Wang, Chengcheng Zhang, and Yuliang Zhao

Abstract  

Nanosized copper particles are widely used in fields of lubricants, polymers/plastic, metallic coating and ink. Recently, we found that copper particles in different sizes can lead to different toxicological effects. To clarify the target organs of copper particles of different sizes, the inductively coupled plasma mass spectroscopy (ICP-MS) was employed to evaluate the distribution of copper in different organs of mice after a single dose oral exposure. The results suggest that the main target organs for copper nanoparticles are kidney, liver and blood. Liver is the main damaged organ.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Xingfeng Li, Cheng Jin, Wei Liu, Jian Zhou, Weijun Kong, Bing Dai, Jiabo Wang, Dan Yan, Yanling Zhao, Yun Luo, and Xiaohe Xiao

Abstract

Using microcalorimetry, the characteristic metabolic heat flow power-time curves of S. aureus growth affected by Ursodesoxycholic acid and Hyodeoxycholic acid were measured at 37 °C. The thermal-kinetic parameters such as, growth rate constant k, the maximum power output (P m), the time corresponding to the maximum power output (t p), total heat-production Q t, half inhibitory concentration of the drugs (IC 50) were calculated from the growth curves. For both HDCA and UDCA, with the increasing of concentration, k, P m, and Q t decreased, meanwhile, kc fit a linear equation, t p was prolonged correspondingly. Principle component analysis, the results indicated t p might be the main parameter in evaluating the antibacterial activity of HDCA and UDCA in microcalorimetric method. Combining with t p and IC 50, the results revealed that the differences and trends of antibacterial activity of these bile acid derivatives were: HDCA > UDCA. Structure-activity relationship (SAR) analysis showed that the α-OH at C-3 and C-6 position at equal pace on the steroid nucleus enhanced the hydrophilicity of HDCA, which led to a stronger antibacterial effect than UDCA. In this study, a useful tool was provided to accurately evaluate the antibacterial effects of bile acid derivatives. The thermolysis curve recorded by microcalorimetry could provide a lot of kinetic and thermodynamic information for the study of growth process of living microbial, which could be helpful in the screening of high efficacy antibacterial agents.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors: Yong He, Rui Ding, Hang Liu, Xiao Wang, Jing-Li Xu, Man Feng, Yu-Rong Chen, Chuan-Min Qi, Cheng Peng, Zhao-Hui Zhu, Yong-Hong Dang, Ming Wang, and Yun-Chuan Ma

Abstract  

As degradation product of Antineoplaston A10 in vivo, phenylacetyl glutamine showed antitumor activities. According to literatures, we designed and radiosynthesized a phenylacetyl glutamine derivative, which was achieved under a mild reaction condition. Evaluations in vitro and in vivo were performed on tumor bearing mice. Excitingly, the radiochemical purity of (S)-2-((S)-2-(4-(3-fluoropropyl)benzamido)-3-phenylpropanamido)pentanedioic acid ([18F]FBPPA) was 98%, and besides the best radiochemical yield was up to 46%. T/Bl (Tumor/Blood) and T/M (Tumor/Muscle) ratios of [18F]FBPPA at 60 min post injection were 2.33 and 3.51. Meanwhile, it showed satisfied stability in vitro and in vivo, compared with 2-[18F]fluorodeoxyglucose ([18F]FDG). Although [18F]FBPPA deserved further studies to make optimizations on its structure, the results revealed it might become a potential PET imaging agent for detecting tumors.

Restricted access