PROPELLANTS EXPLOSIVES PYROTECHNICS
·
2023
·Vol. 48
·期 5
·e202200253
·
IF 1.8
Ting You,An Chen,Yimei Liao,Qiang Tian,Xiaohui Duan
To shed light on the structure-property relationship of a methylnitroguanidine (MeNQ)-nitroguanidine (NQ) eutectic, its thermal behavior and microstructure were studied by various techniques. The eutectic composition of MeNQ-NQ with the lowest melting temperature ( T m ) of 149.9 °C was at the mole ratio of 7 : 3, as determined by temperature-composition ( T-X ) and melting enthalpy-composition ( H-X ) diagrams. The MeNQ-NQ eutectic exhibited a homogeneous network structure composed of the plate-shaped MeNQ and acicular NQ enriched phases that resulted in a uniform melting around the T m observed by in situ variable temperature optical microscopy. The X-ray diffraction from MeNQ-NQ eutectic showed peaks that were shifted to low scattering angle, an indication of the expansion of its crystal lattice and the formation of solid solutions. Small-angle X-ray scattering from the sample showed a rough interface between the MeNQ- and NQ-enriched phases. Infrared spectral data showed absorption peaks due to −NH 2 and −CH 3 groups that were red shifted relative to the raw materials, an indication of hydrogen bond interactions between MeNQ and NQ molecules.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Fan Gao,Hao Wen,Sen Feng,Meng Li,Lingyun Zhu,Yongzhi Zhang,Yilong Xi,Xianling Xiang
The emerging contaminants metformin (MET) and its degradation product guanylurea (GUA) are released into aquatic environments through wastewater treatment plants (WWTPs). Thus, the environmental risks of wastewater with more treatments may be underestimated due to the lower effect concentration of GUA and the higher detected concentration of GUA in treated wastewater in comparison with MET. In this study, we aimed to investigate the combined toxicity mode of MET and GUA to Brachionus calyciflorus by simulating the degrees of wastewater treatments through adjustments to the ratio of MET and GUA in medium. The results showed that the 24 h-LC 50 of MET, GUA, their mixtures of equal concentrations and the mixtures of equal toxic units to B. calyciflorus were 907.44, 544.53, 1185.82 and 940.52 mg/L, respectively, demonstrating GUA is significantly more toxic than MET. An antagonistic interaction between MET and GUA was found in mixture toxicity assessments. Compared with the control, MET treatments only significantly affected the intrinsic rate of population increase of rotifers (r m ), while all life-table parameters were significantly affected by GUA. In addition, at medium and high concentrations (120 and 600 μmol/L), the net reproductive rate (R 0 ) and r m of rotifers under GUA were significantly lower than those under MET. Notably, increased proportion of GUA relative to MET in binary-mixture treatments resulted in increased survival risk and reduced fecundity of rotifers. Moreover, the responses of population dynamics to exposures of MET and GUA were mainly attributed to the reproduction of rotifer, indicating that an improved wastewater treatment process is necessary to protect aquatic ecosystems . The study highlights the importance of considering the combined toxicity of emerging contaminants and degradation product in environmental risk assessment , especially the unintentional transformations of parent compound in treated wastewater.
研究领域:
环境科学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Rongzhen Xie,Nannan Shen,Xijian Chen,Jie Li,Yaxing Wang,Chao Zhang,Chengliang Xiao,Zhifang Chai,Shuao Wang
99Tc is one of the most abundant radiotoxic isotopes in used nuclear fuel with a high fission yield and a long half-life. Effective removal of pertechnetate (TcO4–) from an aqueous solution is important for nuclear waste separation and remediation. Herein, we report a series of facilely obtained benzene-linked guanidiniums that could precipitate TcO4– and its nonradioactive surrogate ReO4– from a high-concentration acidic solution through self-assembly crystallization. The resulting perrhenate and pertechnetate solids exhibit exceptionally low aqueous solubility. The benzene-linked guanidiniums hold one of the highest TcO4– removal capacities (1279 mg g–1) among previously reported materials and possess a removal percentage of 59% for ReO4– in the presence of Cl– over 50 times. The crystallization mechanism was clearly illustrated by the single-crystal structures and density functional theory calculations, indicating that TcO4– is captured through a charge-assisted hydrogen bonding interaction and stabilized by π–π stacking layers. In addition, the removal process is easily recycled and no toxic organic reagents are introduced. This work provides a green approach to preliminarily separate TcO4– from high-level nuclear wastes.
研究领域:
化学
·
环境科学
·
核能工程
✓ 已验证
DOI
PubMed
高影响因子
Solar RRL
·
2022
·Vol. 6
·期 7
·2101103
·
IF 9.173
Yao Li,Siqi Li,Yan Li,Xiangnan Sun,Xinding Lv,Yan-Zhen Zheng,Meilan Huang,Xia Tao
The substitution of a portion of methylammonium (MA) for guanidinium (GA) has been verified to be able to enhance the stability of MA-based devices. However, high-dose guanidinium cation will introduce localized distortions to the perovskite lattice structure and destroy the microstructure of the perovskite films, impairing the stability and reproducibility of perovskite solar cells (PSCs) eventually. Herein, for the first time, the NH 4 Br-assisted all-atmospheric two-step process is adopted to fabricate GA-rich (20%) perovskite films. The NH 4 Br induces the formation of the intermediate phase NH 4 PbI 3 and alleviates the disorder of the octahedron caused by the big GA. Consequently, the modified perovskite film shows increased tolerance for the roughness fluctuation and reduced risk of forming voids and pinholes. The fabricated compact GA-rich perovskite films behave extremely well in photovoltaic performance when assembled as carbon-based perovskite solar cells, delivering a high power conversion efficiency (PCE) of 16.19% and stability against moisture and sunlight. Especially, the unencapsulated devices in ambient air sustain 95.1%, 91.8%, and 95.7% of their initial PCEs after 2400 h of storage, after 1000 h of 65 °C heat environment, and after 800 h of sunlight illumination, respectively.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Xiaoye Bi,Dong Xue,Yunpeng Wang,Chencheng Lv,Zexiong Li,Tao Zhao
This research aims to develop a durable and formaldehyde-free flame retardant treatment for cotton fabrics. Phosphorous acid (PA) is employed in conjunction with urea and guanidine carbonate to chemically bond the flame retardant to the cellulose fibers of the fabric. The treated fabrics are evaluated for their flame resistance, comfort, breathability, aesthetics, fire performance, carbon residue, limiting oxygen index, thermal stability, combustion behavior, and fabric properties. The results demonstrate successful grafting of PA onto cotton fabrics, leading to enhanced flame resistance while maintaining the desired fabric characteristics. The treated fabrics exhibit improved fire performance with increased carbon residue from 4.03% to 28.19% and higher LOI values from 18.0% to 43.5%. Moreover, the thermal stability of the fabric is enhanced, resulting in altered combustion behavior characterized by reduced the total heat release from 11.1 kJ/g to 0.1 kJ/g. Importantly, the flame-retardant treatment does not significantly impact the wettability or stiffness of the fabric. This study presents a simple and effective approach to produce highly efficient fire-resistant cotton fabrics, holding promise for various applications where fire safety is a concern.
研究领域:
材料科学
·
纺织工程
·
消防安全
✓ 已验证
产品关联
DOI
高影响因子
PROCESS BIOCHEMISTRY
·
2019
·
IF 2.883
Yu-Xia Wang,Wei-Chao Su,Qin Wang,Yu-Feng Lin,Yuan Zhou,Long-Fang Lin,Su Ren,Yan-Ting Li,Qing-Xi Chen,Yan Shi
In this study, the antityrosinase and antioxidant activities of four guanidine compounds (GCs), including guanylthiourea (GT), guanidine thiocyanate (GTC), phenylguanidine (PG), and phenethyldiguanide (PTDG), were investigated. The results showed that the GCs reduced the monophenolase and diphenolase activities of tyrosinase. The IC 50 values of GT, GTC, PG, and PTDG were 0.27, 3.53, 6.68, and 5.18 mM for monophenolase and 0.23, 3.24, 3.97 and 2.50 mM for diphenolase, respectively. The inhibition of diphenolase activity was reversible for the four GCs. The inhibition types of GT and PTDG were competitive, while those of GTC and PG were mixed. FRAP, ABTS, DPPH, and DNA damage protection assays revealed that only GT possessed significant antioxidant activity. Furthermore, GT was found to decrease the melanin content and expression of TYR, MITF and DCT in both B16F10 cells and zebrafish. Overall, our results indicated that GT can inhibit tyrosinase activity in vitro , which suggests that these GCs are potential candidates for novel small-molecule tyrosinase inhibitors and that GT could have broader application prospects.
研究领域:
药理学
·
生物化学
·
细胞生物学
·
分子生物学
✓ 已验证
产品关联
DOI
高影响因子
CHROMATOGRAPHIA
·
2022
·Vol. 86
·期 2
·185-197
·
IF 2.213
Lin Xinghua,Hao Gugu,Xu Guobin,Sun Fuzhou,Xin Libo,Wu Shuming,Wang Zhongqing,You Jinsong,Huang Fangfang,Song Xuezhi
An unknown peak with a relative retention time (RRT) of 1.47 was noticed in HPLC chromatograms for related substances of mirabegron extended-release tablets. The level of this unknown peak under the accelerated stability condition for 6 months was as high as 0.19%, which had a trend to exceed the identification threshold of 0.2% from ICH Q3B. The purpose of this study was to identify the RRT 1.47 impurity, and we studied its degradation mechanism to control its content to a lower level. The structure of the RRT 1.47 impurity was identified as a mirabegron dimer bridged by methylene via LC–MS and NMR. Investigation on compatibility of drug-excipients indicated that this impurity formed by Mannich reaction between mirabegron and residual formaldehyde in excipients polyethylene glycol (PEG), polyoxyethylene (PEO). Moreover, the determination of formaldehyde content in excipients further proved this speculation. There was a linear relationship between the amount of formaldehyde and the content of generated dimer impurity within a certain range. The reaction between mirabegron and formaldehyde at different temperatures demonstrated that the higher the temperature, the faster the reaction rate and the higher level of this impurity were generated. To understand the kinetics of the reaction, we calculated the rate of dimerization and also the activation energy of the process based on the stability data. During the development of pharmaceutical formulation on mirabegron or similar structure, appropriate excipients should be selected or the formaldehyde content in excipients could be controlled to avoid such reactions to improve the quality of the product.
研究领域:
药物化学
·
制药工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Shiyu Zhang,Runnan Zhang,Runlai Li,Zixuan Zhang,Yafei Li,Hao Deng,Junhui Zhao,Tianrun Gu,Mengying Long,Xiaoyao Wang,Sui Zhang,Zhongyi Jiang
Positively charged nanofiltration membranes hold great potential in Li + /Mg 2+ separation, but their application in alkaline solutions, such as alkaline salt-lake brines has not been reported. Herein, inspired by the arginine's unique structure and biological function, we explore superstrong basic triaminoguanidine (TG) molecule as aqueous monomer to fabricate positively charged polyamide nanofiltration membranes for Li + /Mg 2+ separation. With the Li + /Mg 2+ mass ratios of 1:50 and 1:120, at pH 9.6, the separation factors (S Li,Mg ) of membranes reach 31.8 and 20.9. Meanwhile, at pH 5.6, the S Li,Mg are 46.4 and 36.4, which are the ever-reported highest value and such high S Li,Mg can be well retained in the pH range of 5.6–8.6. The superior Li + /Mg 2+ selectivity stems from the superhigh protonation capacity of guanidine groups in a broad pH range.
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
RSC Advances
·
2017
·Vol. 7
·期 17
·10108-10117
·
IF 3.108
Shengsheng Zhang,Hai Zhang,Li Wang,Xiaofei Liu,Yuntang Wu
Insulin receptor (InsR) and GLUTs play a very important role in pathophysiological changes in terms of diabetes and insulin resistance, and metformin can regulate their expression and activity in order to alleviate insulin resistance. By reference to the molecular structure of metformin, chitosan biguanidine hydrochloride (CSGH) was synthesized by reacting chitosan (CS) with dicyandiamide under microwave irradiation and characterized by FT-IR, 13C NMR spectroscopy and XRD. The substitution degree (DS) of CSGH, measured by potentiometric titration method, varied in the range of 41.8% to 68.5%. After cytotoxicity testing of CSGH, nontoxic samples were selected. Then insulin resistance (IR) model using human hepatocarcinoma HepG2 cells was established, and the effect of CSGH on glucose consumption was investigated. Moreover, the expression of InsR and the signal protein glucose transporters-2 (GLUT2) were further investigated to study the mechanism. Results showed that CSGH samples with DS 43.2% and DS 52.7% were nontoxic and could improve the vitality, markedly promoting the glucose consumption of HepG2 cells. Besides, the effect of CSGH (DS 52.7%) on promoting glucose consumption was better than metformin and not dose-dependent. It is also found that CSGH could induce the expression of InsR protein and significantly inhibit the over-expression of GLUT2 transport protein, which was probably the mechanism of the therapeutic effect of CSGH on IR HepG2 cells.
研究领域:
药物化学
·
细胞生物学
·
糖尿病研究
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CELLULAR AND MOLECULAR MEDICINE
·
2018
·Vol. 22
·期 5
·2774-2790
·
IF 4.302
Qiongli Su,Ting Tao,Lei Tang,Jun Deng,Kwame Oteng Darko,Sichun Zhou,Mei Peng,Shanping He,Qing Zeng,Alex F. Chen,Xiaoping Yang
Pyruvate kinase M2 (PKM2) regulates the final step of glycolysis levels that are correlated with the sensitivity of anticancer chemotherapeutic drugs. THP is one of the major drugs used in non-muscle-invasive bladder cancer instillation chemotherapy. However, low response ratio of THP (19.7%) treatment to human genitourinary tumours using collagen gel matrix has been observed. This study aims to investigate the effect of down-regulation of PKM2 on THP efficiency. Via inhibitor or siRNA, the effects of reduced PKM2 on the efficiency of THP were determined in 2 human and 1 murine bladder cancer cell lines, using MTT, cologenic and fluorescence approaches. Molecular mechanisms of PKM2 on THP sensitization were explored by probing p-AMPK and p-STAT3 levels via WB. Syngeneic orthotopic bladder tumour model was applied to evaluate this efficiency in vivo, analysed by Kaplan-Meier survival curves, body and bladder weights plus immunohistochemistric tumour biomarkers. PKM2 was overexpressed in bladder cancer cells and tissues, and down-regulation of PKM2 enhanced the sensitivity of THP in vitro. Activation of AMPK is essential for THP to exert anti-bladder cancer activities. On the other hand, down-regulating PKM2 activates AMPK and inhibits STAT3, correlated with THP sensitivity. Compared with THP alone (400 μmol L −1 , 50 μL), the combination with metformin (60 mmol L −1 , 50 μL) stopped growth of bladder cancer completely in vivo (combination group VS normal group P = .078). Down-regulating the expression of PKM2 enhances the anticancer efficiency of THP. This study provides a new insight for improving the chemotherapeutic effect of THP.
研究领域:
肿瘤学
·
药理学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Meng-Jie Tang,Yu-Tong Ye,Zhen-Zhen Li,Mi-Zhuan Li,Pan-Pan Chen,Qi-Le Zuo,Mian Li,Zhong-Xiu Chen
The effects of metformin on invertase activity and its inhibition on sucrose digestion were studied. The rapid unfolding kinetics of invertases, followed a two-state model with an inactive intermediate formation. The dynamic interaction between metformin and invertase caused the secondary structure of the enzyme to become less β-sheet, more α-helix, and random coiling oriented, which weakened the binding force between enzyme and its substrate. Metformin acted as a chaotrope and disrupted the hydrogen bonds of water, which facilitated the unfolding of invertase. However, some sugar alcohols, which promoted the H-bond formation of water, could repair the secondary structure of metformin-denatured invertase and therefore regulate the enzyme activity. This research enriches our understanding of the mechanism of enzyme unfolding induced by guanidine compounds. Moreover, because metformin and sugar substitutes are of concern to diabetes, this research also provides useful information for understanding the activity of the digestive enzyme that coexists with metformin and sugar alcohols.
研究领域:
生物化学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Haocheng Yang,Xuejie Guo,Rongrong Chen,Qi Liu,Jingyuan Liu,Jing Yu,Cunguo Lin,Jun Wang,Milin Zhang
In seawater, biofouling caused by marine organisms’ adhesion on the surface of adsorbent would lead to a significant decrease in adsorption property. Herein, a poly (guanidine-hexamethylenediamine-phytic acid) hybrid sponge (PGHPA-PDF-MF) was synthesized for integration of uranium uptake from seawater with antibiofouling property. The PGHPA-PDF-MF sponge exhibited the superhydrophilicity and retained nearly 29 kPa of compression stress after 1000 cycles. Noteworthy, the PGHPA-PDF-MF sponge showed obviously anti-algae growth behavior (88% cell death rate) due to its guanidine and phytic acid groups, as well as inhibit adhesion of algae ( Nitzschia ) and mussels ( Mytilus edulis ) by the co-effect of its function groups, 3D porous sponge structure and superhydrophilic surface. The saturated U-uptake amount of PGHPA-PDF-MF sponge was high as 531.9 mg/g at nearly seawater pH (~8.0). At 5th cycle, the sponge still had superior reusability and maintained a high removal amount (200.7 mg/g). The uranium uptake amount of PGHPA-PDA-MF sponge was 44.75 mg/g with 90.9% of removal efficiency in uranium and Nitzschia contained artificial seawater at 7 days. Furthermore, more than 80% of uranium removal rate for the PGHPA-PDF-MF sponge in natural seawater (Bohai, China) also showed its great potentiality for actual application.
研究领域:
材料科学
·
环境科学
✓ 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）