Tuning alginate-bentonite microcapsule size and structure for the regulated release of P.putida Rs-198

In this study, different sizes of microcapsules with alginate and bentonite as natural macromolecular materials were prepared to investigate the release property of Pseudomonas putida Rs-198. The characteristics of three microcapsules were evaluated by SEM, FTIR, TG-DSC, XRD and wall thickness. The sizes of three microcapsules(MA, MB, and MC) were 1270.50, 831.79 and 42.52 μm, respectively. First, the encapsulation efficiency of three MA, MB, and MC microcapsules were 82.20%, 90.41%, and 85.84%, respectively.Second, the contact angles of MA and MB samples were similar, while smaller microcapsules MC have higher contact angle(85.05°), indicating poor hydrophilia and decreasing the swelling degrees. Third,the release cumulant of Rs-198 and macromolecule BSA linear stage was fitted to self-established mathematic model. Results show that the microcapsule size had a considerably positive effect on release detail. The large microcapsule possessed strong leak-tightness for Rs-198 as a slow-release microbial agent. Furthermore, the porosity of microcapsules determined their swelling and release and may affect bacterial growth and survival. In conclusion, the Rs-198 microcapsule with different sizes will be pertinently selected based on the characteristics of agricultural production requirements.

Preparation of slow-release regulated Rs-198 bilayer microcapsules and application of its lyophilized bacterial inoculant on Capsicum annuum L.under salt stress

The survival adaptation of bacteria in saline soil is poor.The bilayer microcapsules were prepared by secondary embedding of monolayer sodium alginate(NaAlg)-bentonite(Bent)-sodium carboxy-methylcellulose(CMC)microcapsules wrapped with plant growth promoting rhizobacteria(PGPR)Pseudomonas putida Rs-198 by chitosan solution to promote the synergistic effect of bilayer microen-capsulation and PGPR.The characterization of the Rs-198 bilayer microcapsules showed that the amino and carboxyl groups were cross-linked and a thin layer of chitosan was formed on the outside of the microcapsule.The bilayer microcapsule(Ch-d)with a chitosan concentration of 0.8 wt%and pH 6 showed a slow release of bacteria with a maximum release of 6.06 × 10^(9) cfu/g on the 7th day.The viable bacteria of Ch-d increased by 4.42%after 60 days of storage compared with monolayer microcapsules.The 0.9 wt%L-cysteine,10 wt%glycerinum,10 wt%trehalose and 12 wt%soluble starch were added as bacterial protective agents during the process of preparing the Ch-d lyophilized bacterial inoculant(Ch-d LBI).Pot experiments showed that Ch-d LBI exhibited better growth promotion of Capsicum annuum L.under salt stress.Therefore,the bilayer microcapsule as slow-release bacterial inoculant is a potential alternative for sustainable agriculture.

Power Synchronization Compensation Strategy Based on Second-order Compensation Links for Voltage-controlled Inverters in Microgrids

A second-order compensation link is adopted to control voltage-controlled inverters(VCIs) in microgrid systems to enhance the performance of the power synchronization process of the inverter. The second-order compensation link is classified as both a real pole compensator(RPC) and a complex pole compensator(CPC) according to the pole position. Given a model for the VCI power output, the design process for the second-order compensation link, which is equipped with an RPC and a CPC, is detailed. Moreover, the frequency-domain compensation effects of the RPC and CPC are analyzed using the root locus and Bode diagrams of the system before and after compensation. Finally, the compensation effects of the two types of second-order compensators are compared with the commonly used high-pass filter using MATLAB/Simulink, which verifies the RPC and CPC strategies. Simulation results show that the two types of compensators designed in this study can effectively increase the system cutting frequency and improve the phase margin in the frequency domain while accelerating the power synchronization process, simultaneously making it smoother and reducing overshoot in the time domain. The RPC has better gain robustness, whereas the CPC has better time constant robustness. By implementing an RPC or a CPC, the dynamic time of the power synchronization compensation strategy is reduced within 0.5 s, and the overshoot is reduced within 10% in the experiments with two inverters.

纳米孔生物分子检测研究

纳米孔单分子检测技术是一种集操作简单、灵敏度高、检测速度快、无需标记等优点的传感检测技术,广泛应用于蛋白质检测、基因测序和标志物检测等领域。基因测序的费用、灵敏度和精度是该检测技术的发展中亟待解决的主要问题,而开发新型的纳米孔材料则是解决这些问题的关键手段。本文从纳米孔材料的选择和设计角度出发,综述了三种不同的纳米孔,即蛋白质等生物纳米孔、固态纳米孔和新型二维材料纳米孔在生物分子检测方面的应用现状,并比较了生物纳米孔与固态纳米孔的差别。本文也重点阐述了二维材料纳米孔在生物分子检测中的实验和模拟研究进展。最后,对纳米孔检测技术的发展前景进行了展望。

Dexamethasone and compliance affect TTFields efficacy to glioblastoma patients:a systematic review and meta-analysis

TTFields is a novel treating modality of glioblastoma(GBM)which can significantly prolong the overall survival(OS)of newly diagnosed or recurrent glioblastoma.Some researchers have revealed that a variety of factors can affect the efficacy of TTFields.So,we review the available literature about the influencing factors on efficacy of TTFields and then choose two experimentally supported factors:the dose of dexamethasone and compliance of TTFields to perform a meta-analysis.The PubMed,Embase,and the Cochrane Library are searched.Five articles are identified between 2014 and 2017.Three articles are about the compliance of TTFields.Two articles are about the dose of dexamethasone.The Newcastle-Ottawa Quality Assessment Scale(NOS)is used as an assessment tool to evaluate the methodological quality of all included trials.The scale’s range varies from 0 to 9 stars.According to the Cochrane Handbook for Systematic Reviews of Interventions,articles are graded in six items to evaluate the risk of bias.Two reviewers rate the studies independently and the final decision is reached by consensus.Our data shows that the median OS is conspicuously longer in the TTFields group in which the dose of dexamethasone is≤4.1 mg,WMD=9.23[95%CI 5.69-12.78];P<0.05).And the patients whose compliance of TTFields treatment≥75%(≥18 h per day)have a significant lower overall survival risk than the patients whose compliance of TTFields treatment<75%(HR=0.57[95%CI 0.46-0.70];P<0.00001).TTFields is a safe and efficient novel treatment modality.The dose of dexamethasone≤4.1 mg of TTFields treatment and the compliance of TTFields treatment≥75%,≥18 h per day are beneficial to the prognosis of the glioblastoma patients.