Ultrasound-Assisted Extraction,Preliminary Characterization,and Antioxidant Activity of a Novel Water-Soluble Polysaccharide from Lotus (Nelumbo nucifera Gaertn.) Seeds

Ultrasound-assisted extraction was employed to extract polysaccharides from lotus (Nelumbo nucifera Gaertn.) seeds. Response Surface Methodology was used to determine the optimal extraction conditions of ultrasound power, extraction time, and extraction temperature at 406 W, 7.7 min, and 94°C, respectively. The crude extract was successively purified by chromatography, yielding a major polysaccharide fraction termed LSPS-1. It is a heteropolysaccharide, containing rhamnose, arabinose, glucose, and galactose with a molecular weight of 4484 Da and an α-dominating configuration in pyranose form sugar. Preliminary antioxidant activity test in vitro showed LSPS-1 could potentialize the scavenging effect on hydroxyl radicals in a dose dependent manner.     

Optimization of Microwave-Assisted Extraction of Astaxanthin from Haematococcus Pluvialis by Response Surface Methodology and Antioxidant Activities of the Extracts

Abstract

Microwave-assisted extraction (MAE) was applied for the extraction of astaxanthin from Haematococcus pluvialis and response surface methodology (RSM) was used to optimize extraction parameters to the content of astaxanthin. Four independent variables such as microwave power (W), extraction time (sec), solvent volume (mL), and the number of extraction were optimized in this paper. The optimal conditions were determined and tri-dimensional response surfaces were plotted from the mathematical models. The F-test and p-value indicated that microwave power, extraction time, the number of extraction, and their quadratic had a highly significant effect on the response value (p <0.01), then the solvent volume and the interaction effects of microwave power and the number of extraction also displayed significant effect (p <0.05). Considering the extraction efficiency, the optimized conditions of MAE were as follows: microwave power was 141 W, extraction time 83 sec, solvent volume 9.8 mL, the number of extraction four times. About 594 ± 3.02 µg astaxanthin was extracted from Haematococcus pluvialis the dried powders (100 mg) under the optimal conditions, and it close to the predicted contents (592 µg). The antioxidant activities of the extracts obtained under optimal conditions were analyzed, and the results showed that the extracts presented strong ability of inhibiting the peroxidantion of linoleic acid, exhibited strong radical-scavenging properties against the DPPH, as well as strong reducing power.     

农业推广硕士专业学位研究生培养研究

农业推广硕士是与农业相关领域任职资格相联系的专业学位,通过对农业推广硕士教育、培养中存在问题的分析,结合该专业学位教育的特点,提出了相应的探索建议,即拓宽生源渠道、提高生源质量、教学方式多样化、加强双导师队伍建设等。     

化工生产对总控工素质及技术的要求

以聚氯乙烯化工生产过程为例,针对化工总控工的具体工作内容、专业技能和心理素质等方面进行分析。在化工生产中,化工总控工不但要熟知岗位任务和职责,还要有过硬的专业知识、良好的心理素质。生产中,要求化工总控工明确理解化工生产反应原理,并在出现问题时及时有效进行工艺调整。只有具有专业知识技术,能提出合理化的建议,并不断增强个人综合素质,化工总控工才能保障化工生产安全,提高产品质量,为化工行业的可持续发展创造有利条件。     

甾体含氮化合物的合成及抗肿瘤活性研究

当甾体化合物中引入杂原子时,其化学性质受杂原子影响,生理活性也常常发生改变。从简单的甾体化合物出发,合成出6个化合物并对其中5个化合物进行了体外抗肿瘤活性研究。     

新型芳腙基噻唑衍生物的合成及抗菌活性研究

以取代苯甲醛与氨基硫脲为原料合成了11种芳基噻唑衍生物,经IR、1HNMR、MS及元素分析确定了化合物的结构,并分别测试了这些化合物对8种革兰氏阳性、阴性菌和3种真菌的抑菌活性。     

Synthesis of a novel nanostructured zinc oxide/baghdadite coating on Mg alloy for biomedical application: In-vitro degradation behavior and antibacterial activities

In this research, zinc oxide (ZnO) and zinc oxide/baghdadite (ZnO/Ca₃ZrSi₂O₉) were prepared on the surface of Mg alloy using physical vapor deposition (PVD) coupled with electrophoretic deposition (EPD). For this purpose, the nanostructured ZnO was prepared with a thickness of 900 nm and crystallite sizes of 64 nm as under layer while nanostructured baghdadite with a thickness of 10 µm was deposited on the Mg alloy substrate as an over-layer. Electrochemical measurement exhibited that the ZnO/Ca₃ZrSi₂O₉-coated specimen has a higher corrosion resistance and superior stability in simulated body fluid (SBF) solution in comparison with the ZnO-coated and bare Mg alloy samples. Antibacterial activities of the uncoated and coated specimens were evaluated against various pathogenic species (Escherichia coli, Klebsiella pneumoniae, and Shigella dysenteriae) via disc diffusion method. The obtained results showed that ZnO and ZnO/Ca₃ZrSi₂O₉ coatings have great zones of inhibition (ZOI) against E. coli, Klebsiella, and Shigella. However, less ZOI was found around the bare Mg alloy. Therefore, ZnO/Ca₃ZrSi₂O₉ is a promising coating for orthopedic applications of biodegradable Mg alloys considering its excellent antibacterial activities and high corrosion resistance.     

Enhancement in the photocatalytic and optoelectronic properties of erbium oxide by adding zinc oxide and molybdenum

Rare earth metals like erbium oxide (Er₂O₃) show outstanding photocatalytic properties. However, its high recombination rate and low surface area limit its performance. Therefore, various metal oxide composites with Er₂O₃ have been reported to improve their photocatalytic and optoelectronic properties. In this study, a composite of Er₂O₃ and zinc oxide (ZnO) was synthesized using the sol-gel combustion method to enhance its surface area. Moreover, molybdenum (Mo) was loaded on the matrix to suppress the charge recombination. The detailed characterizations were conducted by employing X-ray Diffraction (XRD), Raman Spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Brunauer–Emmett–Teller (BET) analysis, Photoluminescence (PL) spectroscopy and UV–Vis spectroscopy. BET analysis revealed the enhancement in surface area by adding ZnO and Mo (from S_BET = 29.07 m²/g to S_BET = 45.71 m²/g). Additionally, the loading of Mo enhanced the immobilization of carriers that facilitate the photooxidation process and suppressed the electron-holes recombination (from 800 counts to 100 counts) as confirmed by the PL spectroscopy. Photocatalytic studies were comparatively analyzed by degradation of textile dye named methylene blue (MB). The efficiency of Er₂O₃ improved by up to 80% by adding the ZnO and Mo. The composite of Er₂O₃ with ZnO and loading of Mo, not only improved the photocatalytic properties but also improved the electrical properties of the Er₂O₃ (σ = 4.4 × 10⁻⁴ Sm⁻¹ to σ = 5.1 × 10⁻⁴ Sm⁻¹) as confirmed by the Hall Effect. Due to enhancement in properties, the proposed material can be rendered as one of the most suitable candidates for optoelectronic applications.     

四种国民常用饮水中非挥发性有机物及其致突变活性的比较研究

比较我国居民常用饮水种类自来水、净化水(自来水经净水器过滤)、凉开水(自来水经煮沸后冷却)、纯净水(自来水经以反渗透为主的多重工艺处理)的非挥发性有机物(NOP)污染状况及其致突变活性。结果表明,四种水中检测到的NOP种类分别为自来水39种,净化水40种,凉开水20种,纯净水8种;毛细色谱显示的NOP总丰面积值依次为5.62×109,5.57×109,2.65×109,1.87×109。四种水的移码型及碱基置换型致突变活性依次为:自来水>净化水>凉开水>纯净水,其中自来水在相当1L、2L、4L水量的剂量均为阳性致突变活性,而纯净水在同样的剂量均为阴性。     

因特网上化学化工资源的开发及利用

随着计算机网络技术的迅速发展，利用Internet游览和获取化学信息已成为查阅化学化工文献最重要的方法之一，在化学化工工作者中普及Intemet网上查阅各类化学化工信息和获取这些资源的方法非常重要。本文详细介绍了因特网上化学化工信息的检索方法，包括搜索引擎和信息导航系统、化学化工专业网站、数据库、专利、网上图书馆及电子期刊、化学化工软件、化学仪器及化学试剂供应商的网站，并提供了一些非常实用的专业站点。