2D2D HILIC-ELSD/UPLC-Q-TOF-MS Method for Acquiring Phospholipid Profiles and the Application in Caenorhabditis elegans

Phospholipids are the main constituent of cellular membranes and have recently been identified to have diagnostic value as biomarkers for many diseases. Accordingly, much emphasis is now laid on developing optimal analytical techniques for the phospholipid profiles of various biological samples. In the present study, different classes of phospholipids are first separated by optimized hydrophilic interaction chromatography with evaporative light scattering detector (HILIC-ELSD). The phospholipids in each class are then identified by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Validation results confirm that this approach meets the requirements of quantitative analysis. Finally, the approach is adopted to analyze the phospholipid profiles in Caenorhabditis elegans. A total of 111 phospholipid species is identified according to the mass fragments. Major fatty acyl chains in phospholipids are found to be formed by oleic acid (C18:1), arachidonic acid (C20:4), and eicosapentaenoic acid (C20:5). Overall, this study improves current knowledge on analytical techniques of the phospholipid composition in C. elegans and provides a basis for future lipidomics research. Practical applications: Phospholipids reportedly play a crucial role in the development of many diseases. Until now, only a small portion of phospholipids in Caenorhabditis elegans has been reported by using one-dimensional analysis strategy. The offline 2D2D liquid chromatography method developed in this study identifies 111 phospholipid species in Caenorhabditis elegans. The obtained phospholipid profiles complement the lipid database of Caenorhabditis elegans. The study also provides the basis for the future development of a 2D online approach

Intrachromosomal Looping Is Required for Activation of Endogenous Pluripotency Genes during Reprogramming

SummaryGeneration of induced pluripotent stem cells (iPSCs) by defined factors is an extremely inefficient process, because there is a strong epigenetic block preventing cells from achieving pluripotency. Here we report that virally expressed factors bound to the promoters of their target genes to the same extent in both iPSCs and unreprogrammed cells (URCs). However, expression of endogenous pluripotentcy genes was observed only in iPSCs. Comparison of local chromatin structure of the OCT4 locus revealed that there was a cohesin-complex-mediated intrachromosomal loop that juxtaposes a downstream enhancer to the gene’s promoter, enabling activation of endogenous stemness genes. None of these long-range interactions were observed in URCs. Knockdown of the cohesin-complex gene SMC1 by RNAi abolished the intrachromosomal interaction and affected pluripotency. These findings highlight the importance of the SMC1-orchestrated intrachromosomal loop as a critical epigenetic barrier to the induction of pluripotency

Constraint Satisfied Model Predictive Control Strategy for MMC Energy Storage System Based on Super Capacitor

With the continuous development of power electronics technology and the large-scale access of new energy power generation, the stable operation of the power grid is facing huge challenges. The MMC energy storage system has attracted more and more attention due to its strong ability to support the grid. However, the MMC energy storage system has a complex structure and contains many devices, and the research on high-performance control technology has always been a difficult point. In response to the above problems, this article proposes a constraint satisfaction model predictive control method for MMC energy storage system based on super capacitor. In the article, the operation mechanism of MMC energy storage system is analyzed, and the discrete domain mathematical model of MMC-ESSC is established. The article studies the prediction method of the future internal and external variables of the system, the rolling optimization mechanism and the method of establishing the objective function, and finally carries on the experiments verification. The analysis of experimental results shows that proposed control technology has high dynamic characteristics and efficiency

Characterization of a New Flavone and Tyrosinase Inhibition Constituents from the Twigs of Morus alba L.

The twigs of Morus alba L. were found to show strong tyrosinase inhibition activity, and the responsible active components in the extract were further investigated in this study. A flavone, named morusone (1), and sixteen known compounds 2–17 were isolated from M. alba twigs and their structures were identified by interpretation of the corresponding ESI-MS and NMR spectral data. In the tyrosinase inhibitory test, the compounds steppogenin (IC50 0.98 ± 0.01 µM), 2,4,2′,4′-tetrahydroxychalcone (IC50 0.07 ± 0.02 µM), morachalcone A (IC50 0.08 ± 0.02 µM), oxyresveratrol (IC50 0.10 ± 0.01 µM), and moracin M (8.00 ± 0.22 µM) exhibited significant tyrosinase inhibition activities, much stronger than that of the positive control kojic acid. These results suggest that M. alba twig extract should served as a good source of natural tyrosinase inhibitors for use in foods as antibrowning agents or in cosmetics as skin-whitening agents

Foveated Imaging For Near-Eye Displays

The angular resolution of current near-eye display devices is still far below human-eye acuity. How to achieve retina-level resolution while keeping wide field-of-view (FOV) remains a great challenge. In this work, we demonstrate a multi-resolution foveated display with two display panels and an optical combiner. The first display panel provides a wide FOV but relatively low resolution for the surrounding region, while the second one offers an ultrahigh resolution for the central fovea region, by an optical minifying system which enhances the effective resolution by 5 ×. In addition, a switchable Pancharatnam-Berry phase deflector is employed to shift the high-resolution region. The proposed design effectively reduces the pixelation and screen-door effect in near-eye displays

Compact See-Through Near-Eye Display With Depth Adaption

Based on the recent development of Pancharatnam–Berry deflectors and lenses, we propose a compact and lightweight near-eye display system with depth adaption. The compact design results from the polarization selectivity of Pancharatnam–Berry deflector waveguide coupler, and the fast-switching Pancharatnam–Berry lenses can be exploited for generating correct light fields

Polarization-Multiplexed Multiplane Display

We demonstrate a polarization-multiplexed multiplane display system for near-eye applications. A polarization-sensitive Pancharatnam–Berry phase lens is implemented to generate two focal depths simultaneously. A spatial polarization modulator is utilized to direct the two images to designated focal planes. Based on this design, a dual-focal-plane display system is constructed without space- or time-multiplexing operations, to suppress the vergence-accommodation conflict successfully

Fermentation quality, aerobic stability and in vitro gas production kinetics and digestibility in total mixed ration silage treated with lactic acid bacteria inoculants and antimicrobial additives

The objective was to evaluate the effectiveness of lactic acid bacteria (LAB) inoculants and chemical additives on the fermentation quality, aerobic stability and in vitro gas production kinetics and digestibility of total mixed ration (TMR) silage. Total mixed ration (568 g/kg dry matter (DM)) was ensiled with six experimental treatments: (1) no additives (control); (2) Lactobacillus buchneri (LB; applied at 1 × 106 cfu/g fresh weight (FW)); (3) Lactobacillus casei (LC; applied at 1 × 106 cfu/g FW); (4) calcium propionate (CAP; applied at 0.5% FW); (5) sodium diacetate (SD; applied at 0.5% FW); (6) potassium sorbate (PS; applied at 0.1% FW). All silos (18 L) were opened for fermentation quality, in vitro gas production kinetics and digestibility analysis after 90 days of ensiling, and then subjected to aerobic stability test for 14 days. All the TMR silage was well-preserved with low pH (4.36 ∼ 4.66) and acceptable levels of butyric acid (1.02 ∼ 2.51 g/kg DM) and ammonia nitrogen (86.3 ∼ 107 g/kg total nitrogen). All the groups were steady during 14 days of aerobic exposure, while SD group was more stable with lower (p < 0.05) yeast (4.60 vs. 5.17 ∼ 5.77 log10 cfu/g FW) and mould (3.33 vs. 4.12 ∼ 4.64 log10 cfu/g FW) populations than other treated groups on day 14. Moreover, SD group had the highest (p < 0.05) in vitro digestibility of dry matter (67.8 vs. 56.6 ∼ 63.5%) and neutral detergent fibre (61.7 vs. 50.5 ∼ 57.4%) among all groups. Overall, SD is recommended as additive to improve fermentation quality, in vitro ruminal digestibility, and aerobic stability of TMR silage.HIGHLIGHTS After 14 days of aerobic exposure, the yeast and mould populations in TMR silage can be efficiently inhibited by sodium diacetate treatment. Sodium diacetate treatment evidently enhanced in vitro digestibility of dry matter and neutral detergent fibre compared to other treatments. Sodium diacetate is recommended as additive to improve fermentation quality, in vitro ruminal digestibility, and aerobic stability of TMR silage