Fe3O4-nanoparticle-functionalized 3D-printed injectable microgel

Magnetic Fe₃O₄ nanoparticles have attached attention in bone tissue engineering because of their superior magnetism and great biocompatibility. However, some disadvantages such as the potential risk of agglomeration impair their applications. Here, we proposed a hybrid magnetic nanocomposite microgel by the integration of Fe₃O₄ nanoparticles and digital lighting processing (DLP) three-dimensional (3D) printing technology. The 3D-printed microgels could be precisely customized by printing the mixture of gelatin methacryloyl (GelMA) solution and polydopamine-coated Fe₃O₄ nanoparticles, in which polydopamine decoration improved the hydrophilicity and distribution of the incorporated Fe₃O₄. The degradable microgels could be injected through a 22-G needle while retaining their original shape after injection. Interestingly, the addition of Fe₃O₄ nanoparticles into GelMA solution displayed improved printing accuracy. Moreover, these magnetic microgels were biocompatible in vitro and in vivo. After induction within osteogenic medium, addition of nanoparticles upregulated the osteogenic gene expression of rat bone mesenchymal stem cells (BMSCs). In a word, this work provides a magnetic microplatform, which shows great potential in bone tissue engineering.     

Effect of processing conditions on producing a reactive derivative from β‐cyclodextrin with itaconic acid

A reactive cyclodextrin was synthesised by reacting β‐cyclodextrin with itaconic acid to enable it to fix permanently onto cellulosic materials. Because synthesis is a complicated process that is greatly influenced by many factors, the response surface methodology was applied in this study to optimise production. To investigate the efficiency of the esterification reaction, the amount of carboxyl groups and the double bond content of the end product were measured and employed as the responses. The 3D response surface plots and the contour plots derived from the mathematical models were applied to evaluate the interactive effects of parameters affecting the reaction, such as itaconic acid and catalyst concentrations, material to liquor ratio, temperature and time of reaction. The amount of carboxyl groups and the double bond content of cyclodextrin itaconate (about 175 and 150 meq./100 g CDI, respectively) in the optimum conditions indicated that one to two itaconic acid molecules could react with cyclodextrin according to the esterification reaction. In addition, the presence of the new supplementary groups on cyclodextrin could effect on the aggregation behaviour of this new cyclodextrin derivative as demonstrated by dynamic light scattering and AFM.     

The Determination of Average Stability Constant of NickeI-FA Complex at pH = 8,0 by the Solubility Method

At pH = 8, the complex formation process of Ni（Ⅱ） ions with FA was studied by the solubility method. FA were separated from the river Mtkvari by the adsorption-chromotographic method. The charcoal （BAU, Russia） was used as a sorbent. The old suspension of Ni（Ⅱ） hydroxide was used as the solid phase, on which was added the increasing quantity of standard solution of FA. In diluted solutions, at pH = 8.0 the dominant form of Ni（Ⅱ） is nickel dihydroxocomplex Ni（OH）2^0. It was established that in the Ni（OH）2（solid）-Ni（OH）2^0（solution）-FA2-H20 system dominates nickel dyhydroxofulvate complex with the structure 1：1, [Ni（OH）2FA]2-. The average stability constant of nickel dyhydroxofulvate complex was calculated based on experimental data flNi（OH）2FA2＂ = 5.3 × 105.     

An Unexpected Potassium Iodide‐Promoted Nucleophilic Substitution Reaction between 2‐Acyloxy‐2H‐azirines and Carboxylic Acids

The acyloxy group of 2‐acyloxy‐2H‐azirines has been displaced by carboxylic acids to generate the corresponding 2‐acyloxy‐2H‐azirines by using potassium iodide as a promotor. This metal‐free method can be performed with a wide scope of substrates readily generating products in moderate to high yields. It also represents an example of nucleophilic substitution between esters and carboxylic acids under metal‐free reaction conditions for the first time.

     

Green synthesis of ZnO nanoparticles by Olive (Olea europaea)

Green synthesis of nanoparticles is superior to physical and chemical methods as it is environment‐friendly and cost‐effective. The present study was carried out for inducing nanoparticles synthesis by zinc nitrate in the leaves extracts of olive. Further leaves extracts were evaluated for antiradical scavenging activity by 1, 1‐diphenyl‐2‐picryl‐hydrazyl assay. Morphological and structural properties of the synthesised ZnO nanoparticles have been characterised using UV‐Vis spectrophotometer, FTIR, TEM, XRD and dynamic light scattering (DLS) analysis. Further, zinc oxide nanoparticles were evaluated for antiradical scavenging activity by capacity of total antioxidant assay. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. FTIR investigation suggested that the flavonoids, glycosides, proteins and phenols molecules can play an important role in the stabilisation of ZnO nanoparticles.Inspec keywords: zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, X‐ray diffraction, light scatteringOther keywords: zinc oxide nanoparticles, green synthesis, physical method, chemical method, zinc nitrate, antiradical scavenging activity, 1, 1‐diphenyl‐2‐picryl‐hydrazyl assay, morphological properties, structural properties, UV‐vis spectrophotometer, FTIR, TEM, XRD, dynamic light scattering analysis, flavonoids, glycosides, proteins, phenols molecules, Olea europaea, ZnO     

超声辅助原位合成Al_2O_3颗粒增强铝基复合材料

针对Al-CuO反应体系,利用熔体直接反应法,施加间接超声辅助,原位合成了Al2O3颗粒增强铝基复合材料。结果表明,高能超声对Al-CuO体系的原位反应有促进作用,施加超声后自生的Al2O3颗粒直径为1~2μm,较未施加超声的数量多,在晶内与晶界弥散分布。间接超声处理的适宜温度为665~675℃,超声后在875℃保温30min有利于Al2O3颗粒生成及弥散分布。高能超声的促进作用主要表现在声空化和声流效应对CuO粉和Al熔体间润湿性的改善以及对团聚CuO粉末的分散,本质是对Al-CuO体系原位反应的热力学与动力学环境的优化。     

Investigation of ZnO nanoparticles on proline,anthocyanin contents and photosynthetic pigments and lipid peroxidation in the soybean

The interaction between nanoparticles and plants is inevitable. In this study, the effect of different concentrations of ZnO nanoparticles synthesised using olive extract on the soybean was studied. The soybean seeds were cultured in a Hoagland medium containing agar which was treated different concentrations (0, 200 and 400 ppm) of ZnO nanoparticles. After 21 days, the plants were harvested and the parameters of proline, anthocyanin, malondialdehyde (MDA), hydrogen peroxide (H₂ O₂), chlorophyll and carotenoid contents and phenylalanine ammonia‐lyase (PAL) and catalase (CAT) activity in soybeans (Glycine max) were measured. The results showed that the levels of chlorophyll a and b and carotenoid at concentrations of 200 and 400 ppm in comparison with control decreased, while carotenoid content at 200 ppm concentration at a concentration of 400 ppm was not significant. The level of anthocyanin and PAL activity increased with increasing concentration of nanoparticles, while proline content decreased. By increasing the concentration of ZnO nanoparticles, the content of MDA and hydrogen peroxide increased compared to control but CAT activity did not change significantly. This research suggests that ZnO nanoparticles synthesised using olive extract in soybean plants may be toxic by reactive oxygen species production.Inspec keywords: crops, pigments, enzymes, nanoparticles, zinc compounds, toxicology, agricultural safety, nanobiotechnology, hydrogen compoundsOther keywords: carotenoid content, proline content, ZnO nanoparticles, soybean plants, H₂ O₂ , ZnO, time 21.0 d, reactive oxygen species production, toxicity, catalase activity, phenylalanine ammonia‐lyase activity, chlorophyll content, Hoagland medium, olive extract, lipid peroxidation, photosynthetic pigments, hydrogen peroxide, anthocyanin contents     

Evaluating Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data for alteration zone enhancement in a semi‐arid area,northern Shahr‐e‐Babak,SE Iran

The visible–near infrared (VNIR) and short wave infrared (SWIR) spectral bands of both the level 1B, radiance at sensor, and level 2, AST_07 surface reflectance data products of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument were evaluated and compared for mapping the alteration zones around porphyry copper deposits and occurrences at the northern Shahr‐e‐Babak, SE Iran. The level 1B data were converted to reflectance using internal average relative reflectance (IARR) method whereas the AST_07 dataset was processed as delivered. The porphyry copper mineralization occurs in Eocene, andesitic and basaltic rocks with zonal alteration patterns that are concentric and almost symmetrically arranged. The spectral signatures of alteration index minerals collected from field samples and the United States Geological Survey (USGS) spectral reference library, were considered in directed principal component analysis (DPCA) and spectral angle mapping (SAM) algorithms. Carrying out the DPCA method on three spectral bands enhanced the alteration haloes in the last principal component (PC) images. Generating RGB colour composite images using these PC images differentiated three alteration zones from the host rocks. The SAM results of the IARR calibrated dataset discriminated the propylitic, argillic and phyllic alteration zones. It is concluded that the higher spectral resolution of ASTER instrument is effective for mineral mapping. However, the method of conversion from radiance to reflectance is critical to the validity of the outputs and that the pseudo‐reflectance method using the IARR process may be more reliable than the standard reflectance product.     

活性氧与蜡样芽孢杆菌菌膜形成的相关性

为阐明活性氧（ROS）与蜡样芽孢杆菌菌膜形成的相关性,以市售原料奶中分离的蜡样芽孢杆菌分离株为目标菌,以细菌中NADPH氧化酶介导产生的ROS为主要靶点,用外源ROS补充剂过氧化氢(H₂O₂)、ROS清除试剂N-乙酰半胱氨酸（NAC）、NADPH氧化酶抑制剂二苯基氯化碘盐（DPI）处理蜡样芽孢杆菌,测定分析ROS变化与菌膜形成之间的关系。结果表明,0.01 μmol/L H₂O₂、1 μmol/L H₂O₂、100 μmol/L H₂O₂处理组平均菌膜形成量均显著高于对照组平均菌膜形成量（P<0.05）,0.1 μmol/L H₂O₂、10 μmol/L H₂O₂处理组平均菌膜形成量与对照组平均菌膜形成量相比无显著性差异（P>0.05）,随着H₂O₂浓度的升高,ROS逐渐下降。NAC各处理组平均菌膜形成量均显著高于对照组平均菌膜形成量（P<0.05）,随着NAC浓度的升高,ROS逐渐下降。DPI浓度≤1 μmol/L时,随着DPI浓度的升高,平均菌膜形成量均显著高于对照组平均菌膜形成量（P<0.05）,ROS逐渐下降;DPI浓度>5 μmol/L时,随着DPI浓度的升高,平均菌膜形成量显著低于对照组平均菌膜形成量（P<0.05）,ROS含量升高。表明在不影响蜡样芽孢杆菌生长和细胞活性的前提下,一定浓度的H₂O₂、NAC和DPI处理菌株能够诱导ROS减少,增强蜡样芽孢杆菌菌膜的形成。激光共聚焦显微镜结果显示,与对照组相比处理组具有更强的染色效果,呈现红色的网络结构,而未经处理组呈现松散的结构和更少的菌膜生物量,这表明ROS对蜡样芽孢杆菌菌膜的形成存在抑制作用。