Frontiers in Pharmacology
·
2021
·
IF 5.811
Yu Kunzi,Liu Wei,Zhang Nanping,Cheng Xianlong,Zhou Shiyu,Zuo Tiantian,Kang Shuai,Wei Feng,Ma Shuangcheng
Maidong, the root tuber of Ophiopogon japonicus (Thunb.) Ker Gawl., is a commonly used herbal medicine in China. There are three quality grades of Maidong according to traditional opinion and modern research studies: superior quality (Zhe-Maidong), medium quality (Chuan-Maidong), and poorest quality (Chuan-Maidong with paclobutrazol, which is a kind of plant growth regulator). However, no efficient way to distinguish the three quality grades of Maidong exists; thus, the herbal markets and botanical pharmacies are flooded with Chuan-Maidong with paclobutrazol. To ensure the safety and quality of Maidong, a comparative microscopic study was performed on three quality grades of Maidong. The result was to establish a microscopic quantification method based on the area ratio between xylem and pith to distinguish the three quality grades of Maidong. Subsequently, Maidong from regional markets was evaluated by this method. In this study, we developed a novel quantification method to identify the three quality grades of Maidong, which could in turn make efforts on the quality improvement of Maidong. Our study is the first to demonstrate that microscopic technology could be used to distinguish different quality grades of a specific herbal medicine.
研究领域:
中药学
·
植物显微学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Shuai Chen,Wei Zhou,Yani Ding,Guangbo Zhao,Jihui Gao
Understanding the evolution of carbon structure in coal-assisted water electrolysis for hydrogen production (CAWE) is essential for seeking strategies to improve the rate of CAWE and getting more insight into the potential significance of CAWE. In this work, 13C nuclear magnetic resonance (NMR) is used to make out the evolution of carbon structure in CAWE. First, the electrolysis characteristics of three different-rank coals are revealed using electrochemical methods. Then, before and after electrolysis, the evolution of carbon structure is analyzed. The results show that CAWE is a process of reducing carbon and increasing oxygen, and the accumulation of oxygen-containing groups is mainly owing to the increase of oxygen aliphatic carbons and oxygen aromatic carbons. After CAWE, the aromatic cluster size decreases and increases for low-rank coals and high-rank coals, respectively.
研究领域:
能源科学
·
材料化学
✓ 已验证
DOI
高影响因子
iScience
·
2023
·
IF 5.8
Ye Zhao,Xueyong Yin,Yang Yu,Shihao Huang,Hao Feng,Shuang Wang,Yiming Cai,Ruofan Zhao,Shuai Gao,Ye Liu,Zhengxin Zhang,Xinyu Zhao,Ruonan Qiao,Jialin Yuan,Weichen Guan,Huiping Yang,Yun Shi,Haishui Shi
Huddling behavior, a typical social interaction among animals, has the benefits of obtaining social support and adapting environment. Huddling behavior is determined by social (social hierarchy), environmental factors (stress events), and the neuroendocrine system. Nevertheless, the huddling behavior of different social hierarchies and the underlying mechanisms have not been fully elucidated. In the present study, acute 2-methyl-2-thiazoline (2 MT) can induce huddling behavior and significantly increase serum levels of testosterone (T) in mice; and the increased T level was positively correlated with huddling behavior. Further, the T treatment significantly increased the huddling behavior in mice under 2 MT exposure condition. More interestingly, T can quickly promote dominant individuals to occupy safe positions when huddling together under predator odor. Collectively, T can rapidly regulate the individual's adaptive response to threats in a social rank-dependent manner, which provides a new perspective for the in-depth study of the influencing factors and underlying mechanisms of huddling behavior.
研究领域:
神经生物学
·
内分泌学
·
行为学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 137
·期 1
·47411
·
IF 1.901
Zhun Li,Chuanchuan Liu,Weihong Cao,Qiang Yao
To take the advantage of reactivity of five-membered cyclic phosphorus compounds, 1,2,3-tri-phenyl-1,3,2-diazaphospholidine-2-oxide (TPDPO) was explored as a reactive flame retardant for epoxy resins (EPs). Through model compounds, it has been established that TPDPO selectively reacts with the secondary hydroxyl group and is inert toward both aryl amino groups and epoxide groups. The result of Soxhlet extraction supports that TPDPO is permanently bonded to the cured EPs. At a loading of only 8 wt % (0.74 wt % phosphorus), TPDPO enables the cured epoxy to achieve a UL-94 V0 rating. The thermogravimetric analysis–Fourier transform infrared analyses of the gaseous products suggest that the excellent flame retardancy of EP–TPDPO is partly due to the enhanced dehydration process of the epoxy. Also an increased char yield and the formation of a coherent char layer contribute to the good fire performance of EP–TPDPO. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 47411.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Zhiyuan Tang,Xueyuan Yang,Kun Zhang,Kuanjun Fang
In cotton fabric inkjet printing, the spreading and penetration of the ink seriously damage printing resolution and color strength. In this study, hydroxypropyl methyl cellulose (HPMC) with varying viscosity grades (6, 30, 100, 400, and 4000 mPa·s) were used for fabric pretreatment to reduce the ink spreading and penetration. The results indicated that HPMC with a high viscosity grade enhanced the ability of pretreatment paste to form a continuous HPMC film on the fiber surface. A continuous film could greatly increase the hydrophobicity of the fabric, thereby restricting the spreading and penetration of ink. Meanwhile, ink migration was also limited by the paste connected to the fibers and the swelling of the film, which was more significant at higher HPMC viscosity grades. However, the increase of the HPMC viscosity grade was not conducive to dye fixation. Additionally, HPMC with a viscosity grade of 100 mPa·s was considered a reasonable choice, which could improve printing resolution and color strength in industrial applications. This research provides a new approach for optimizing pretreatment paste to achieve high-quality printed products.
研究领域:
纺织科学
·
材料科学
·
印刷技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 13
·51860
·
IF 3.125
Jia Chen,Li Rong,Wei Fang,Jiyan Liu,Xueqing Liu
A novel approach has been proposed to enhance the flame retardancy of ABS by a highly efficient intumescent flame retardant coating, which was prepared by aluminum- ethylene glycol methyl propionate cyclohexanediol phosphonate (EMPCP-Al), polyvinyl formal (PVFO) and melamine cyanurate with specific ratio. When the average thickness of coating achieved at 106 μm, the limit oxygen index value of ABS increased from 16.6% to 28.7%, its UL-94 rating reached V-0 level in the vertical burning test, and the peak value of heat release rate (PHRR) was decreased by 51.1% compared with that of pure ABS. TGA coupled with Fourier transform infrared spectroscopy was used to probe the degradation behavior of the flame retardant composites. In addition, the microscopic morphology and graphitization degree of the carbon layer which obtained after the thermal degradation of the flame retardant composites were investigated by scanning electron microscopy-energy dispersive X ray and Raman spectroscopy. Moreover, P element, N element and Al element in flame retardant coating exhibited benign synergistic flame retardancy in the gas phase and condensed phase. Furthermore, the flame retardant coating could effectively avoid the damage to intrinsic mechanical properties of ABS caused by high loading of flame retardant additives.
研究领域:
材料科学
·
阻燃技术
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2022
·
IF 5.204
Shuang-Lin Hu,Ying-Ming Li,Wen-Juan Hu,Jose Hobson,De-Yi Wang
Unsaturated polyester resin (UPR) composites with excellent flame retardancy and high mechanical property is a great challenge to its widely application. In present work, a highly efficient flame retardant (MA-DOPO) containing nitrogen, sulfur and phosphorus elements was designed via a nucleophilic substitution reaction of amino and aldehyde groups. For the UPR/MA-DOPO 15 composites, its tensile strength was 28.3 MPa, which was 19.9 % higher than that of neat UPR attributing to the formation of hydrogen bonds with UPR. It should be noted that tensile strength of UPR/MA-DOPO 20 composites reached the highest 39.6 MPa, showing a growth trend with the enhancement of incorporation amount of MA-DOPO. Meanwhile, the UPR/MA-DOPO 15 composites passed the UL-94 V-0 rating with a LOI of 27.0%, and the peak heat release rate (PHRR) and total heat release rate (THR) were reduced by 35.1% and 41.6% in cone calorimeter (CC) test comparing to that of neat UPR respectively. Moreover, the detailed flame-retarding mechanism of MA-DOPO was investigated by the thermogravimetric infrared spectroscopy (TG-IR), Raman spectrum, X-ray photoelectron spectroscopy (XPS) and pyrolysis-gas chromatography/mass spectrometry (PY-GC/MS), in which the releasement of inert gas in gas-phase and the catalytic carbonation in condensed phase jointly taking effect.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Tong-Yu Bai,Xiang-Xin Xiao,Guan-Qi Zheng,Qin Zhang,Zi-Ni Wang,Li Chen,Bo-Wen Liu,Yu-Zhong Wang
Polycarbonate is a widely used engineering plastic material, but its limited flame retardancy has restricted its application in high-end fields such as aviation and railways. In this study, we propose a novel copolymerization/macromolecular blending strategy to produce a high-performance, fire-safe polycarbonate composite. By copolymerizing with polydimethylsiloxane oligomer and blending with macromolecular polyarylate, the resulting PC-BPDMS 5 /PITR successfully achieved a UL-94 V-0 rating and a high limiting oxygen index value of 34.2%. The peak heat release and total smoke release were significantly reduced by 45.2% and 27.4%, respectively, compared to pure PC. SEM, Raman, and XPS analyses confirmed the condensed-phase dominated flame-retardant mechanism, attributed to the char-forming ability of the polyarylate and polydimethylsiloxane segments. Polydimethylsiloxane segments can decompose to produce small molecules such as methane, and the left structure with silicon, which undergo cross-linking reactions with the substrate during combustion to promote char formation. The polyaromatic ring structure of PITR can also participate in the formation of a dense and stable char layer. The excellent compatibility between the polyarylate and the PC matrix, combined with the superior flexibility of polydimethylsiloxane, allowed the composite to maintain mechanical properties comparable to pure PC. Additionally, the increased molar volume resulted in a low dielectric constant for PC-BPDMS 5 /PITR. This work presents a promising approach for the development of high-performance polycarbonate composites.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2015
·Vol. 26
·期 3
·255-265
·
IF 1.757
Xuan Zhou,Juan Li,Yonggang Wu
Aluminum hypophosphite (AHP) was introduced into polylactide/intumescent flame retardant (PLA/IFR) systems by melt blending. The flame retardant and thermal properties of the PLA composites were investigated. The results suggest that a synergistic effect exists between IFR and AHP on the char formation and anti-dripping behavior of PLA composites. The PLA/IFR composites containing 10 wt% IFR can pass the UL-94 V-0 rating but the test is accompanied by heavy melt dripping. For the PLA/AHP a UL-94 V-2 rating is obtained for the same loading of IFR. However, the composites containing 7 wt% IFR and 3 wt% AHP pass the UL-94 V-0 rating with modified dripping behavior. Moreover, the char from combustion of PLA/IFR is flexible but of poor quality. That for PLA/AHP is brittle with many cracks. In contrast, that for PLA/IFR/AHP is strong and compact. Thus it can resist the erosion due to heat and gas formation and protect the inside of the matrix. In addition, AHP causes the crosslinking among APP, which promotes the char formation and prevents the melt dripping. This is the main reason for the good flame retardant properties of PLA composites. Copyright © 2015 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
阻燃材料
✓ 已验证
产品关联
DOI
高影响因子
Processes
·
2024
·Vol. 12
·期 11
·2432
·
IF 2.8
Jinghui Li,Bochao Qu,Enlong Zhen,Shufen Ma,Yifei Liu
Multi-scale fractures in Northwest Oilfield are extremely developed. Fractures in both oil flow channels and water channels lead to the phenomenon of water channeling in the later stages of reservoir development, which may be affected by the bottom water cone. Gel plugging agents are widely used in the treatment of this phenomenon because of their low cost and high-water plugging efficiency. However, because there is often residual oil in small-scale fractures, the pressure law of different grades of differential fractures on gel is not clear, thus leading to low gel application efficiency and low oil recovery. There is still a lack of effective means through which to understand the regularity of shielding the remaining oil with gel strength and fractures of different grades. In this study, we conducted a novel analysis of the law of shielding oil production in fractured reservoirs. The gelling and rheological properties of anti-temperature gels (ATGs) with different strengths were studied. The plugging rate of oil phase was 96.39%, and that of water phase was 25.37%. ATG showed good oil–water selectivity. The influences of different grades of differential fractures on the production law of shielding the remaining oil were also studied, as well as the corresponding influence law chart. When the gel strength was in the range of 2.0–28.1 Pa and the fracture grade difference was 5–10, the recovery ratio was increased by 10.6–24%. The enhanced oil recovery can be quantitatively predicted by the scale of reservoir fractures and the strength of gel used. It has a certain guiding role for the field application of gel to efficiently shield residual oil in differential fractures.
研究领域:
石油工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Yuting Guan,Siyu Wang,Guanghua Lei,Zikang Hu,Hengye Chen,Huiwen Gu,Xiaoli Yin,Yuanbin She,Wanjun Long,Haiyan Fu
Enshi Yulu green tea (ESYL) is the most representative traditional steamed green tea in Enshi, Hubei. Different ESYL grades exhibit distinct flavors, tastes, and prices. In this study, a visual sensor based on 4-MPBA Au@AgNPs was developed for the rapid and accurate identification of ESYL grades. The recognition mechanism involved the binding of 4-MPBA Au@AgNPs with polyphenolic compounds in ESYL to form borate esters and the conversion of Ag + to Ag 0 , with the generated Ag 0 depositing on the surface of 4-MPBA Au@AgNPs. The results showed that the sensor can amplify the color differences of different grades of ESYL. The visual results were also validated by the partial least squares discriminant analysis model, demonstrating an enhancement in recognition accuracy from 68.2 % to 95.5 % compared to the original extraction solution. The colorimetric sensor developed in this study is expected to provide a new approach for traceability research of other foods.
研究领域:
食品科学
·
分析化学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 24
·13992-14003
·
IF 2.599
Xiao Fei,Wu Kun,Luo Fubin,Guo Yuyue,Zhang Shiheng,Du Xiangxiang,Zhu Qingqing,Lu Mangeng
In order to develop a highly efficient flame-retardant system, a phosphonate-based ionic liquid named 1-vinyl-3-(diethoxyphosphoryl)-propylimidazolium bromide (IL) was synthesized and introduced into epoxy resin (EP). With only 4 wt% loading, EP/IL composite passed UL-94 V-0 rating, and its limiting oxygen index value increased to 34.9% from 25.9% for neat epoxy resin. The char yield of EP/IL-2 (2 wt%) was improved by 58.3%, and its peak of heat release rate was reduced by 65% compared with that of neat EP. The reason is that the presence of IL promoted the forming of a compact and stable phosphorus-rich residual chars. Unlike traditional additive-type flame retardant, it is very interesting that the introduction of IL changed the color and transparency of EP few and enhanced mechanical property of neat EP remarkably. Owing to the excellent compatibility and steric effect between IL and EP matrix, tensile strength was increased to 108.6 MPa for EP/IL sample from 84.9 MPa for neat EP, indicating the outstanding reinforcement effect of IL on EP composites.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）