Improvement of sediment microbial fuel cell performances by design and application of power management systems

One of the ways to generate clean and non-destructive energy is to use the energy stored in the biomass resources by the microbial fuel cells (MFCs). Sediment Microbial Fuel Cells (SMFCs) are a special type of MFCs that use organic materials in aquifers sediment to generate electricity. In this research, the effects of an increase in the electrode surface are investigated. The results showed that the increase in cathode electrode surface had better efficiency than the multi-cathode mode (maximum power generated for a 3-cathode electrode (27 cm³) and 1-cathode electrode (27 cm³) was 526 mW/cm² and 800 mW/cm², respectively. Another parameter affecting the performance of these systems is temperature. In the next step, the power generation rate was measured in different step currents and at different sample times. In the final stage, a power management system (PMS) was designed to optimally utilize the output energy of the improved SMFC, leading to an increase in the output voltage to 3.3 V.     

Isolation and characterization of Listeria monocytogenes in Chinese food obtained from the central area of China

The objective of this study was to investigate the prevalence and characteristics of Listeria monocytogenes isolated from Chinese food, including frozen dumplings, flavored raw meat, roasted meat, braised meat, and a cold vegetable dish with sauce. A total of 900 food samples were collected from supermarkets, open-air markets, and delicatessens in three large cities in the central area of China to examine the presence of L. monocytogenes; 21 (2.3%) of the samples were positive for this pathogen. Among the different samples, braised meat showed the highest L. monocytogenes detection rate (4.4%). Samples obtained from delicatessens showed a much higher L. monocytogenes contamination rate (8.3%) than those from open-air markets (6.7%) or supermarkets (0%). Multilocus sequence typing (MLST) analysis indicated that the 21 bacterial isolates belonged to 12 ST subgroups. ST5 was the largest and contained 7 isolates (33.3%); it was followed by ST474, ST121 and ST9 (each containing 2 isolates [10.5%]). Antibiotic susceptibility analysis showed that the 21 L. monocytogenes isolates were thoroughly resistant to cefoxitin but highly susceptible to doxycycline and ciprofloxacin. The presence of 10 virulence genes was evaluated by PCR, which showed that inlA, inlC, inlJ, prfA, hlyA, and plcB were present in all isolates and that inlB, actA, plcA and iap were present in 71.4–90.5% of the isolates. This study provides a useful reference for risk assessment and control of L. monocytogenes contamination in Chinese food and for the treatment of clinical listeriosis.     

Rapid and sensitive detection of Pseudomonas aeruginosa in bottled water by loop-mediated isothermal amplification

A loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Pseudomonas aeruginosa in bottled water was developed and evaluated. Four primers, including two outer primers and two inner primers, were specially designed by targeting the ecfX gene. The LAMP assay showed high specificity, with no false-positive or false-negative results among the 108 bacterial strains tested, including 81 strains of P. aeruginosa. The detection limit in pure culture was 15.7 CFU/mL, which is approximately 100-fold more sensitive than that of ecfX-PCR. In artificially contaminated water samples spiked with low level (3.1 CFU/250 mL) of P. aeruginosa, the LAMP assay could detect the target organisms accurately after 10 h of enrichment, in contrast to 12 h of enrichment for ecfX-PCR. In the case of bottled water samples, 9.17 % (10/109) of the samples were found to be positive by LAMP, which was in accordance with the results from GB 8538-2008 method. The LAMP assay established in this study is a simple, sensitive, and rapid protocol for the detection of P. aeruginosa. It provides an important diagnostic tool for the drinking water produce industry and regulatory agencies to better control potential risks associated with consumption of bottled water.     

抗氧化剂及其增效剂对荔枝、龙眼和芒果原果汁的抗氧化作用研究

以热带水果荔枝、龙眼、芒果为研究对象,选取叔丁基羟基茴香醚（BHA）、没食子酸丙酯（PG）、特丁基对苯二酚（TBHQ）、二丁基羟基甲苯（BHT）及茶多酚等作为抗氧化剂,柠檬酸、苹果酸、磷酸、葡萄糖酸钙、EDTA等作为抗氧化增效剂,进行单体和复合抗氧化剂抗氧化试验。结果表明：对龙眼果汁的抗氧化能力从大到小排列为：TBHQ〉BHT〉茶多酚〉PG〉BHA;各种增效剂均可明显增加TBHQ的抗氧化能力,对龙眼果汁的抗氧化能力从大到小排列为：TBHQ＋苹果酸＋EDTA〉TBHQ＋苹果酸〉TBHQ＋柠檬酸〉TBHQ＋EDTA〉TBHQ＋磷酸〉TBHQ＋葡萄糖酸钙;TBHQ加入柠檬酸及EDTA增效后对荔枝、芒果原果汁的抗氧化效果理想,VC保存率均达到85%以上。     

活性炭的筛选及其吸附饮用水中低量溴化物的研究

本文通过研究星光K02活性炭、星光K04活性炭和太西活性炭等六种活性炭对饮用水中低量溴化物的吸附效率,筛选出了吸附效果最佳的太西活性炭。同时探讨了不同的活化方式、不同的吸附时间以及饮用水中不同的p H值对TAC(太西活性炭)吸附饮用水中低量溴化物(7.50μg/L)效率的影响。实验采用了蒸馏水浸泡和稀盐酸浸泡两种活化方式,用CO_2酸化的方式将饮用水中pH值分别调至6.00、7.00和7.68三个水平,在不同的时间点取样,用离子色谱仪检测其溴化物含量。不同条件下,TAC吸附溴化物效率不同。实验结果表明,用稀盐酸浸泡作为活化方式,同时将饮用水的p H值调至6.00,在实验开始后的两个小时内TAC吸附溴化物效果最佳,能达到85.35%,此时溴化物含量为1.10μg/L,即使在后续的臭氧灭菌阶段,溴离子全部被氧化成溴酸盐,溴酸盐的值会在5μg/L以内,远小于GB 5749-2006和GB 8537-2018中溴酸盐的规定限值(10μg/L),同时,TAC对饮用水中的常量元素钾钠钙镁、微量元素锶及偏硅酸等影响不大(小于10%)。因此,在实际生产中,可先将饮用水中p H值调至6.00,然后采用盐酸溶液预处理后的TAC对饮用水中低量溴离子进行去除。     

广东虫草抗疲劳及延寿作用的研究

通过研究广东虫草对正常小鼠游泳时间及其对果蝇寿命延长作用的影响,初步反映其抗疲劳及延寿作用。抗疲劳实验结果表明,广东虫草低、中、高剂量组小鼠的游泳时间与阴性对照组比较显著性延长(P<0.01);对果蝇寿命的延长作用实验中,中剂量的广东虫草对雌雄果蝇的平均寿命及半数死亡寿命均有一定的延长作用,且在雌性中的效果优于雄性。实验结果证明,在该研究的实验条件下,广东虫草具有明显的抗疲劳作用及延寿作用,且均在中等剂量时效果最为明显。     

ε-聚赖氨酸纯化的工艺优化

本研究选用弱酸型D113阳离子交换树脂,以ε-聚赖氨酸的解吸率为评价指标,以解吸液盐酸浓度、吸附pH值、解吸时间、解吸温度进行单因素试验,并根据试验结果确定因素及水平,进行正交试验.结果显示,影响ε-聚赖氨酸解吸率的因素从大到小为:解吸时间＞解吸温度＞解吸液的盐酸浓度＞吸附pH.最佳条件为:解吸时间12h、解吸温度25...     

Platinum-based photosensitizer with near-infrared aggregation-induced emission for synergistic photodynamic-chemo theranostics

Photodynamic therapy (PDT) is of great interest as an emerging paradigm towards cancer treatment, owing to its advantages of minimal invasiveness and low toxicity. In this work, we incorporated cisplatin into an AIE-based photosensitizer (BT) and achieved a highly efficient antitumor drug (BT-Pt). Possessing AIE characteristics, BT-Pt exhibited NIR fluorescence with large Stokes shift in cells, which can guide the location of the drug. More importantly, the ROS generation efficiency of BT-Pt has extremely been promoted with the fabrication of cisplatin, compared with BT. As a result, BT-Pt demonstrated favorable therapeutic efficacy with a half maximal inhibitory concentration (IC₅₀) value of 1.54 μM for HeLa cells upon white light irradiation, attributed to its synergetic PDT and chemotherapy. The design strategy of such platinated photosensitizer showed great potential in developing multifunctional anticancer drugs with combinatorial photodynamic–chemotherapy, especially when ablating cisplatin resistant cancer cells and hypoxic tumors.