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关键词： Anticancer   Chitosan   Ionic gelation   Methotrexate   Nanoparticles   Phytic acid  

摘要： Methotrexate-loaded phytic acid-chitosan nanoparticles were synthesized by ionic gelation assisted by high-intensity sonication. The nanoparticles were characterized by particle size, polydispersity index, zeta potential (ZP) and encapsulation efficiency. Their physical stability was evaluated at 4 degrees C and 40 degrees C, whereas the in-vitro methotrexate release was assessed at pH 7.4. The data were heuristically fit to first-order, Higuchi, Peppas-Sahlin and Korsmeyer-Peppas models of release kinetics. Anticancer activity was evaluated using the 3-(4,5-di-methylthiazol-2-yl) 2,5 diphenyltetrazoliumbromide (MTT) assay on HT-29 human colon adenocarcinoma cells. Physicochemical analysis showed that the nanoparticles presented positive ZP values, sizes less than < 300 nm and low polydispersity, except for systems formed with low amplitude sonication. The nanoparticles exhibited an adequate physical stability and a capability to modify methotrexate release by a non-Fickian mechanism, resulting in a more pronounced cytotoxic effect than the free drug on HT-29 human colon adenocarcinoma cells.

关键词： Gelatine   nasal pack   genipin   fess   nasal wound   nasal injury  

摘要： Nasal injury following nasal surgery is an adverse consequence, and prompt treatment should be initiated. Nasal packing, either non-absorbable or absorbable, are commonly used after nasal surgery to prevent bleeding and promote wound healing. In the current study, a novel gelatine sponge crosslinked with genipin was evaluated for suitability to be used as nasal packing and compared to one of the frequently used commercial nasal packing made up of polyurethane. Gelatine at 7% and 10% (w/v) concentration were crosslinked with varying concentrations of genipin, 0.5%, 0.25%, and 0.2% (v/v). The gelatine sponges were further characterised by its water uptake ability, biodegradation, water vapour transmission rate, porosity, contact angle, chemical composition, crosslinking degree, and mechanical properties. The gelatine sponges absorbed five times more water than their dry weight and were degraded within five days. The water vapour transmission rate of the gelatine sponges was 1187.7 +/- 430.2 g/(m(-2)day) for 7% gelatine and 779.4 +/- 375.5 g/(m(-2)day) for 10% gelatine. Crosslinking of gelatine with genipin resulted in lower porosity and did not affect the wettability of gelatine sponge (contact angle: 95.3 +/- 12.1 degrees for 7% gelatine and 88.4 +/- 7.2 degrees for 10% gelatine). In terms of biodegradability, the gelatine sponges took 24-48 h to degrade completely. Genipin crosslinking improved the degradation resistance and mechanical strength of gelatine sponge. The physical and chemical properties of the gelatine sponge, i.e. biodegradability and mechanical durability, support its potential as nasal packing.

关键词： Hawthorn wine pomace   Extraction method   Hawthorn pectin   Physical and chemical properties   Antioxidant activity  

摘要： In the paper, to enhance the value and utilization rate of hawthorn wine pomace waste, four kinds of pectin were gained from hawthorn wine pomace by hydrochloric acid method (HA-HP), citric acid method (CA-HP), cellulase method (E-HP) and microwave-assisted chelating agent method (MH-HP). The physical and chemical properties of extracted hawthorn pectin were analyzed, however, different extraction methods lead to different characteristics of extracted pectin samples. We found that the extracted hawthorn pectin was all low-methoxy pectin, and the highest extraction yield of 72.89% with high ash (9.20%) was obtained by the MH-HP method, while the galacturonic acid (Gal A) content was up to 72.24% after dealing with the CA-HP method which was the highest among the four samples, besides, the quality of gel formed by E-HP method was the best. What's more, the four extracted samples all reveled degrees of antioxidant activity with dose-dependent in vitro antioxidant, and it was CA-HP method had the best antioxidant activity, making this the first comprehensive research describing the extracting pectin from hawthorn wine pomace. This research also provides a base for industrial production of high-value products from low-cost raw materials. (C) 2020 Elsevier B.V. All rights reserved.

关键词： T2EHDCA   D2EHPA   Physicochemical   Density   Viscosity   Irradiation  

摘要： The physicochemical properties of the combination of a neutral and an acidic extractant used in the one cycle process for the mutual separation of An(III) and Ln(III) have been investigated in detail. The extractants used are: N,N,N',N'-tetra(2-ethylhexyl) diglycolamide (T2EHDGA) and bis(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-dodecane (n-DD). The properties such as dynamic viscosity (eta), density (rho), phase separation time (PST) and interfacial tension (IFT) were measured as a function of various experimental parameters such as temperature, concentration of extractant, the concentration of nitric acid, etc., for both irradiated and unirradialed solvent phases. The change in viscosity and density of 0.1 M T2EHDGA/n-DD phase was ascertained by varying the concentration of D2EHPA from 0.1 M to 0.3 M in it owing to find out the effect of D2EHPA in the organic phase and it showed the increasing trend in both viscosity and density values upon addition of D2EHPA. The energy of activation and the isobaric coefficient of thermal expansion of the solvent phases were accessed. The refractive index (n) of T2EHDGA, D2EHPA and their mixture in n-DD phase was also evaluated in neat as well as irradiated conditions and reported in the paper. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Diesel exhaust particles   Soot reactivity   Nanostructure   Aromatics addition  

摘要： To evaluate the effects of aromatics structure on physicochemical features of diesel exhaust particles, particulate samples emitted from diesel fuel and its mixtures with benzene, m-xylene and tetralin were characterized using high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). Results showed that diesel soot had the least reactivity among four particle samples, followed by diesel/tetralin soot, which the latter was less reactive than diesel/m-xylene and diesel/benzene soot. In this aspect, diesel fuel with high proportion of aromatics, especially monoaromatics, demands lower thermal energy input for diesel particulate filter (DPF) regeneration. Higher reactivity of diesel/aromatics soot was in line with the less ordered nanostructure. Fringe parameters obtained from HRTEM showed that fringe length of soot particles decreased in the order: diesel > diesel/tetralin > diesel/m-xylene > diesel/benzene, while both fringe tortuosity and separation distance exhibited the opposite trend with fringe length. Notably, the effects of fuel formulations on fringe parameters were slight. Moreover, both I-D1/I-G and A(D1)/A(G) values revealed that diesel soot had a greater ordered structure than diesel/aromatics soot. The mean primary particle diameters of diesel/aromatics soot were larger than those of soot from pure diesel fuel. After mixing with aromatics, the mass fraction of volatile substances in particle samples increased while elemental carbon contents decreased. According to XPS, no relationship was observed between the surface oxygen content (O/C ratio) and the soot reactivity.

关键词： MCM-41   物理化学   亚甲基蓝   吸附  

摘要： 介绍一个物理化学综合实验。本实验以制备的有序介孔二氧化硅MCM-41为吸附剂,研究了水溶液中亚甲基蓝在其表面的吸附性能。通过利用Langmuir和Freundlich吸附等温式对吸附数据进行分析、处理和拟合。本综合实验教学不仅促进学生对材料结构与性能的认识,而且加强了学生对固体表面吸附过程的理解。

关键词： Bio-indicators   Heavy metals   Monogenea   Physicochemical parameters   Quadriacanthus  

摘要： Fish parasites can be used as bio-indicators to evaluate pollution degree in aquatic ecosystems. Limited research has, however, investigated the potentiality of these parasitic worms to tolerate various environmental factors. This study, therefore, investigated whether the gill, Quadriacanthus monogenean parasites of Bagrus bajad Forskål, 1775 are potential bio-indicators of aquatic ecosystem health. The seasonal differences in prevalence, mean intensity and abundance of Quadriacanthus species of Clarias gariepinus varied between each other and between the three localities. Most Quadriacanthus species exhibited their highest prevalence, mean intensity and abundance in Spring and/or Summer and their lowest values in Autumn and/or Winter. The seasonal differences in prevalence were significant for Q. kearni and Q. clariadis while a significant difference in the mean intensity between different seasons was recorded only for Q. aegypticus. Also, seasonal differences in the abundance were highly significant for Q. aegypticus and significant for Q. kearni. The total dissolved solids, Chlorides, Sulphate, Sodium, Cadmium and Lead were higher at Manzala Lake than standard permissible limits. The pH has significant correlations with the infestation levels of all Quadriacanthus spp. Dissolved oxygen showed a highly significant positive correlation with the mean intensity of Q. clariadis and a significant positive correlation with the abundance of Q. clariadis. Iron was the only heavy metal to record a significant positive relationship with the mean intensity of Q. kearni. It is noteworthy that Quadriacanthus species were found to have a noticeable ability to resist the effect of hazardous concentrations of many physicochemical and heavy metals parameters. Therefore, it is highly recommended that these monogeneans could be regarded as bio-indicators for water quality. © 2020, Indian Society for Parasitology.

关键词： 线上教学   物理化学   教学模式  

摘要： 新冠疫情下,各高校纷纷启动了线上教学。本文探索了物理化学课程线上教学模式的形成,包括教学平台的选择,教学过程的重组,考核方式的调整,互动方式的多维组合,以及对在线教育的思考,为线上教学的实施提供有益的参考。

关键词： 高校教育   新冠疫情   教学改革   物理化学  

摘要： 在新冠疫情蔓延与“互联网+”时代的大背景下,全国各大高校普遍采用线上教学模式来代替传统的线下授课。线上教学的模式避免了人群的聚集,让教学资源更方便获取,但同时也面临着设备及网络不稳定、教学质量难以保证等问题。而《物理化学》这门课的内容大多较为抽象,许多知识点需要学生花大量时间去思考和理解。所以在线上教学中,为了保证教学质量,教师要构建起翻转课堂,注重课后的答疑与学生的课前预习,积极引导学生自主学习。展望未来,线上教学不会只是一时的应对手段,而会融入进来,使线上线下相结合,推动教育事业的发展,开创出未来教育新局面。