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关键词： 物理化学实验   虚拟仿真技术   远程教学   教学改革  

摘要： 物理化学实验不仅可以帮助学生直观地理解理论知识,还能使学生提高动手操作能力及分析解决问题的综合能力。传统物理化学实验存在学生预习效果不佳、实验过程指导难度大、成本高等缺点。尤其在COVID-19疫情期间,传统物理化学实验难以开展,学生实验教学的问题也更加突出。而虚拟仿真实验正是解决疫情期间理工科学生难以完成实验难题的“钥匙”。本文详细阐述了传统物理化学实验课程的不足之处,探讨了虚拟仿真实验的优势及其应用现状。

关键词： 虚拟仿真   合成   表征   MLabs  

摘要： 固体催化剂的合成、表征和应用是多相催化技术的核心内容,但其合成周期长、表征所需大型仪器众多,因此在本科教学实验中难以实际开展。依托大连理工大学科研课题,以ZSM-5分子筛为研究对象,采用虚拟仿真技术,通过19步的人机互动实现了催化剂合成、表征及催化性能评价全过程。教学实践表明,虚拟实验对真实实验的模拟可以有效解决本科生在多相催化领域的核心技术和研究方法等方面能力缺失问题,加深学生对理论知识的理解,提高学生的学习兴趣,培养学生的自主创新能力。

关键词： 微信公众平台   物理化学   教学方法改革   移动学习  

摘要： 基于大数据互联网技术创建了“物理化学新世界”微信公众号,探讨了“物理化学新世界”微信公众号在物理化学教学过程中作为一种辅助学习手段的作用及在大数据时代利用碎片化时间移动学习中的重要性。对应用化学专业学生物理化学课程的学习将会收到更好效果。微信公众号在新时代互联互通环境下的教学改革中将具有重要意义。

关键词： Fish bone   Hydroxyapatite   Carboxymethyl cellulose   Implant coating  

摘要： In this study, we described the facile synthesis of hydroxyapatite (HAP) through thermal decomposition of Rogu fish bones (Labeo Rohita) and this prized biominerals is used for bone implant applications. The HAP coating on Ti6Al4V alloy was performed through electrophoretic deposition (EPD) along with carboxymethyl cellulose (CMC) extracted from rice husk and sodium alginate (SA). The physicochemical and structural behaviour of the HAP and its biocomposites were investigated through various characterization techniques such as fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM). The physicochemical characterizations confirmed the formation of phase pure apatite structure. The HAP and its biocomposites coated implants were investigated in simulated body fluid (SBF) so-lution to determine the biomineralization on the implant surface. The biomineralization process reveals that the HAP/CMC biocomposite containing 2 wt % SA exhibit better apatite formations on the implant surface than the other biocomposite coated implants (1 wt % and 3 wt % SA). Microhardness of the HAP and its biocomposites were investigated through Vicker's microhardness measurements. The antibacterial activity confirms that the as-synthesized HAP does not possess any bacterial activity. Furthermore, the high surface negative charge of SA containing HAP/CMC biocomposite shows better antibacterial activity against the gram-positive strain. The cell proliferation investigation for the 2 wt % SA containing HAP/CMC biocomposite against MG63 cell line exhibits high cell affinity, which reveals that the HAP/CMC/SA composite confirms the biocompatible nature of the biocomposite.

关键词： 物理化学   药学   考核模式   过程性评价   教学评价  

摘要： 为更好地适应应用技术型药学人才培养的需求,提高教学质量,在现代网络技术的支持下,对药学专业物理化学课程考核模式进行了一系列优化改革,建立了过程性评价(60%)和期末考试(40%)相结合考核新模式。过程性评价包括:考勤签到(5%)、随堂测验和抢答(10%)、分组主题汇报(15%)、作业和章节考查(30%)。实践证明,相比于传统的单一的终结性考核,这种考核新模式促进了教师“教”的创新与学生“学”的主动性,有效提升了教学质量。

关键词： Starch   Cellulose nanocrystals   Magnetic field   Biodegradable films   Alignment  

摘要： The magnetic field (MF) induced alignment of cellulose nanocrystals (CNC) within a starch matrix is investigated and its effect on the physicochemical and mechanical properties of the nanocomposites are discussed in the paper. Two different kinds of CNC i.e. plant-CNC and tunicate-CNC and its hybrid combination are studied to understand the effect of aspect ratio of CNC on the properties of nanocomposite. Nanocomposites with tunicate sourced CNC showed higher tensile strength and modulus, and lower water vapor permeability as compared to plant sourced CNC. These properties are higher for nanocomposites prepared under MF. The modulus of starch nanocomposites increased from 0.26 GPa and 0.32 GPa to 0.38 GPa and 0.44 GPa, respectively for plant-CNC and tunicate-CNC when exposed to MF. The improved orientation and alignment of CNC in presence of MF is further supported by Raman and scanning electron micrographs studies.

关键词： Matrix vesicles   Langmuir monolayers   Phosphatidylserine   Biomineralization   Calcium phosphate  

摘要： Bone biomineralization is an exquisite process by which a hierarchically organized mineral matrix is formed. Growing evidence has uncovered the involvement of one class of extracellular vesicles, named matrix vesicles (MVs), in the formation and delivery of the first mineral nuclei to direct collagen mineralization. MVs are released by mineralization-competent cells equipped with a specific biochemical machinery to initiate mineral formation. However, little is known about the mechanisms by which MVs can trigger this process. Here, we present a combination of in situ investigations and ex vivo analysis of MVs extracted from growing-femurs of chicken embryos to investigate the role played by phosphatidylserine (PS) in the formation of mineral nuclei. By using self-assembled Langmuir monolayers, we reconstructed the nucleation core - a PS-enriched motif thought to trigger mineral formation in the lumen of MVs. In situ infrared spectroscopy of Langmuir monolayers and ex situ analysis by transmission electron microscopy evidenced that mineralization was achieved in supersaturated solutions only when PS was present. PS nucleated amorphous calcium phosphate that converted into biomimetic apatite. By using monolayers containing lipids extracted from native MVs, mineral formation was also evidenced in a manner that resembles the artificial PS-enriched monolayers. PS-enrichment in lipid monolayers creates nanodomains for local increase of supersaturation, leading to the nucleation of ACP at the interface through a multistep process. We posited that PS-mediated nucleation could be a predominant mechanism to produce the very first mineral nuclei during MV-driven bone/cartilage biomineralization.

关键词： E174   silver   particle size distribution   TEM   spICP-MS   food additive  

摘要： Silver (E174) is authorised as a food additive in the EU. The unknown particle size distribution of E174 is a specific concern for the E174 risk assessment. This study characterised the fraction of silver (nano)particles in 10 commercially available pristine E174 food additives and 10 E174-containing products by transmission electron microscopy (TEM) and single-particle inductively coupled plasma-mass spectrometry (spICP-MS). TEM analysis showed that all samples contained micrometre-sized flakes and also a fraction of (nano)particles. Energy-dispersive X-ray spectroscopy (EDX) and electron diffraction confirmed that the (nano)particles and micrometre-sized flakes consisted of silver. A higher amount of (nano)particles was observed in the products than in the food additives. In addition, the surface of the micrometre-sized flakes was rougher in products. The median of the minimum external dimension, assessed as minimal Feret diameter, of the fraction of (nano)particles determined by quantitative TEM analysis was 11 +/- 4 nm and 18 +/- 7 nm (overall mean +/- standard deviation), for food additives and products, respectively. Similar size distributions were obtained by spICP-MS and TEM, considering the limit of detection of spICP-MS. The median of the equivalent spherical diameter of the fraction of (nano)particles determined by spICP-MS was 19 +/- 4 nm and 21 +/- 2 nm (overall mean +/- standard deviation), for food additives and products, respectively. In all samples, independent of the choice of technique, the nano-sized particles represented more than 97% (by number) of the silver particles, even though the largest mass of silver was present as flakes.

关键词： 棉纤维   TEMPO氧化   乳液   抗氧化   儿茶素  

摘要： 为改善花生油的储存稳定性,以2,2,6,6-四甲基哌啶-1-氧基自由基(TEMPO)氧化棉纤维为乳化剂,制备花生油乳液。通过平均粒径、Zeta电位、过氧化物值(PV)和硫代巴比妥酸值(T-BAR)测定,表征乳液的物理和化学储存稳定性。结果表明,改性纤维素可有效增大乳液的Zeta电势,减小乳液的平均粒径,提高乳液的物理储存稳定性。同时,改性纤维素可显著降低乳液的PV值和T-BAR值,改善乳液的化学储存稳定性。此外,改性纤维素与儿茶素对油脂的抗氧化性具有协同增强作用。利用TEMPO氧化纤维素有望彻底解决不饱和脂肪酸长期稳定储存的难题。

关键词： Deep eutectic solvents   Physicochemical properties   Hydrogen bond   Benzilic acid  

摘要： Recently, deep eutectic solvents (DESs) have been introduced as new types of green solvents due to their environmentally friendly, non-toxicity, and favorable physicochemical properties over conventional organic solvents. Therefore, studying their physical properties will provide great help to design processes in the application fields. In this work, four new DESs are successfully prepared by using benzilic acid (BA) as hydrogen bond donor (HBD) with choline chloride (ChCl), tetraethylammonium bromide (TEAB), tetrapropylammonium bromide (TPAB), and tetrabutylammonium hydrogen sulfate (TBAHS) as hydrogen bond acceptors. The physicochemical properties of the DESs such as density, speed of sound, conductivity, viscosity, refractive index, and surface tension measured as a function of temperature. The melting temperatures of the DESs have been measured by using the Differential Scanning Calorimetry (DSC) method and the H-1, C-13 NMR, and Fourier transforms infrared (FTIR) analysis carried out to confirm their chemical structure, purities, and occurrence interaction between the investigated HBAs and HBD which formed the deep eutectic mixtures. (C) 2020 Elsevier B.V. All rights reserved.