29 research outputs found
Signal identification with Kalman Filter towards background-free neutrinoless double beta decay searches in gaseous detectors
Particle tracks and differential energy loss measured in high pressure
gaseous detectors can be exploited for event identification in neutrinoless
double beta decay~() searches. We develop a new method based
on Kalman Filter in a Bayesian formalism (KFB) to reconstruct meandering tracks
of MeV-scale electrons. With simulation data, we compare the signal and
background discrimination power of the KFB method assuming different detector
granularities and energy resolutions. Typical background from Th and
U decay chains can be suppressed by another order of magnitude than
that in published literatures, approaching the background-free regime. For the
proposed PandaX-III experiment, the search half-life
sensitivity at the 90\% confidence level would reach ~yr
with 5-year live time, a factor of 2.7 improvement over the initial design
target
Optimization of the Best Polar Site for Antioxidant Activity of Panax ginseng Extract Based on Entropy Weight Method and Grey Relational Analysis Combined with Component Analysis
Objective: The differences in antioxidant activity of different polar parts of panax ginseng were investigated to screen the best active parts. Method: In this study, the water extract of Panax ginseng was extracted by petroleum ether, chloroform, ethyl acetate and n-butanol in turn. The contents of total phenolic acids, total saponins, total polysaccharides, total flavonoids, ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1 in different polar parts were determined by high performance liquid chromatography (HPLC) and ultraviolet-visible (UV) spectrophotometer. The in vitro antioxidant activity of different polar parts was determined by DPPH free radical, ABTS+ free radical, hydroxyl radical, superoxide anion free radical and cell oxidative damage model. Combined with entropy weight method and grey relational analysis, the quality evaluation model of different polar parts of Panax ginseng was established. By weighting twelve quality characteristic indexes of different polar parts of Panax ginseng, the best antioxidant polar part of Panax ginseng was ultimately selected. Results: The differences in the components and antioxidant activity of different polar parts of Panax ginseng were obvious. Among them, the content of total phenolic acid, total flavonoids and ginsenoside Rb1 in n-butanol part was higher than that in other parts. The n-butanol part had the best antioxidant activity, and had certain scavenging ability to DPPH free radical, ABTS+ free radical, hydroxyl radical and superoxide anion free radical, and the corresponding IC50 values were 0.14, 0.57, 0.92 and 0.75 mg/mL, respectively. In addition, combined with the quality evaluation model, the relative correlation degrees of range of different polar parts of Panax ginseng was 0.352~0.618, and the relative correlation degree of n-butanol part was the highest (0.618), which further indicated that the antioxidant activity of n-butanol part was the strongest. Conclusion: Based on the evaluation results of entropy weight method and grey correlation analysis, the n-butanol part was preliminarily selected as the most ideal antioxidant part of Panax ginseng, which would provide a theoretical basis for the research of Panax ginseng as a natural antioxidant and the development and application of Panax ginseng antioxidant food
A Grasshopper Optimization-Based Approach for Task Assignment in Cloud Logistics
A framework for the algorithm-based CL platform is established, based on which, the operational mode of it is described in detail. An integrated logistics task assignment model is built to optimally match logistics service resources and task of large scale in the algorithm-based CL. Particularly, an improved grasshopper optimization-based bitarget optimization algorithm (GROBO) is proposed to solve the biobjective programming model for service matching in CL. The case of Linyi small commodity logistics is taken as an application. Simulation results show that the proposed GROBO provides better solutions regarding to searching efficiency and stability in solving the model
Evolution of the Aroma Volatiles of Pear Fruits Supplemented with Fatty Acid Metabolic Precursors
To examine the biochemical metabolism of aroma volatiles derived from fatty acids, pear fruits were incubated in vitro with metabolic precursors of these compounds. Aroma volatiles, especially esters, were significantly increased, both qualitatively and quantitatively, in pear fruits fed on fatty acid metabolic precursors. Cultivars having different flavor characteristics had distinctly different aroma volatile metabolisms. More esters were formed in fruity-flavored āNanguoliā fruits than in green-flavored āDangshansuliā fruits fed on the same quantities of linoleic acid and linolenic acid. Hexanal and hexanol were more efficient metabolic intermediates for volatile synthesis than linoleic acid and linolenic acid. Hexyl esters were the predominant esters produced by pear fruits fed on hexanol, and their contents in āDangshansuliā fruits were higher than in āNanguoliā fruits. Hexyl esters and hexanoate esters were the primary esters produced in pear fruits fed on hexanal, however the content of hexyl ester in āDangshansuliā was approximately three times that in āNanguoliā. The higher contents of hexyl esters in āDangshansuliā may have resulted from a higher level of hexanol derived from hexanal. In conclusion, the synthesis of aroma volatiles was largely dependent on the metabolic precursors presented
Metabolic Profiles of Pomegranate Juices during Fruit Development and the Redirection of Flavonoid Metabolism
The pomegranate (Punica granatum L.) fruit is favorable for its nutrient-rich benefits to human health. However, the global metabolic profiles of pomegranate juice and the metabolic mechanisms of its essential metabolites are poorly understood. In this study, we conducted a widely targeted metabolome, integrated with the transcriptome of juices (edible parts) of pomegranate fruits at 50, 95, and 140 days after flowering (DAF) to comprehensively investigate the metabolic profiles and potential metabolism of essential metabolites. Five hundred and nine metabolites, including 11 sugar and sugar alcohols, 17 common organic acids, 20 essential amino acids, and a variety of flavonoids, were detected in pomegranate juices. Among them, metabolites in the flavonoid biosynthesis pathway greatly changed during fruit development. Notably, the redirection of metabolite flux from catechin and its derivative synthesis to anthocyanin synthesis occurred at the later developmental stages. The increased expression of Pgr021399.1 encoding dihydroflavonol 4-reductase (DFR), Pgr017842.1 encoding anthocyanidin synthesis (ANS), Pgr015322.1 encoding anthocyanidin 3-O-glucosyltransferase (BZ1), Pgr000447.1 encoding UTG75C1, and the decreased expression of Pgr024128.1 encoding leucoanthocyanidin reductase (LAR) may trigger redirection. The results of this study provide a global view of the metabolic profiles of pomegranate juices and valuable information on the molecular mechanisms underlying the redirection of flavonoid metabolism. It also sheds light on the genetic regulation of flavonoid metabolism in pomegranate juices
Unexpected Emission of Poly[(methylenelactide)-co-(2-vinylpyridine)] from Single-chain Luminogen
Non-conjugated luminescent polymers (NCLPs) have attracted great interest due to their novel emission mechanism and potential for applications in a variety of areas. Copolymerization is a facile and effective approach to develop NCLPs from two or more types of non-luminescent comonomers by integrating critical elements that are necessary for inducing intrinsic emissions. In the present work, we report unexpected photoluminescence (PL) of poly[(methylenelactide)-co-(2-vinylpyridine)] random copolymers (PLVPs), which possess intense blue emissions in dilute solution with quantum yield higher than 20 %. The intrinsic PL of PLVPs is attributed to the intra-chain interactions of chains, namely, āsingle-chain luminogenā. As a result, the PL of PLVPs exhibits aggregation-caused quenching (ACQ) feature, which is different from conventional NCLPs based on clustering-triggered emission (CTE). The dependence of emissions on the molecular weights and monomer ratios of PLVPs, as well as excitation wavelength, in both solution and solid states were investigated. This work provides new insight into the design and preparation of NCLPs
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Quantitative Surface Plasmon Interferometry via Upconversion Photoluminescence Mapping.
Direct far-field visualization and characterization of surface plasmon polaritons (SPPs) are of great importance for fundamental studies and technological applications. To probe the evanescently confined plasmon fields, one usually requires advanced near-field techniques, which is typically not applicable for real-time, high-throughput detecting or mapping of SPPs in complicated environments. Here, we report the utilization of rare-earth-doped nanoparticles to quantitatively upconvert invisible, evanescently confined SPPs into visible photoluminescence emissions for direct far-field visualization of SPPs in a complicated environment. The observed interference fringes between the SPPs and the coherent incident light at the metal surface provide a quantitative measurement of the SPP wavelength and the SPP propagating length and the local dielectric environments. It thus creates a new signaling pathway to sensitively transduce the local dielectric environment change into interference periodicity variation, enabling a new design of directly measurable, spectrometer-free optical rulers for rapid, ultrasensitive label-free detection of various biomolecules, including streptavidin and prostate-specific antigen, down to the femtomolar level
Towards an extended food safety culture model : studying the moderating role of burnout and jobstress, the mediating role of food safety knowledge and motivation in the relation between food safety climate and food safety behavior
Nectarine, a variety of peach is rich in bioactive and antioxidant compounds, and both white- and yellow-fleshed nectarine fruits are commercially popular. However, although anthocyanin (flavonoid) and carotenoid biosynthetic pathways play important roles in plant colouration, the molecular basis of fruit flesh colouration remains largely unknown. Accordingly, we performed an RNA sequencing-based transcriptome analysis of two white-fleshed nectarines, Zhongyou9 (ZY9) and Zhongyou13 (ZY13-W), and their yellow-fleshed mutants, Hongyu (HY) and Zhongyou13-Y (ZY13-Y). To differentiate the impact of ripening on gene expression, we also compared ZY9 and HY at two different time points, namely, before and after fruit ripening. We found that the yellow-fleshed HY may accumulate flavonoids through the generation of more flavonoid biosynthesis precursors, as well as through the overexpression of flavonoid synthase genes. In addition, we also found that HY could impede carotenoid degradation via beta-carotene 3-hydroxylase and carotenoid cleavage dioxygenase genes. Meanwhile, ZY13-Y may regulate its yellow colouration through overexpression of chalcone synthase genes, in order to accumulate flavonoids, as well as through the underexpression of flavonol 3-O-methyltransferase and carotenoid cleavage dioxygenase genes, in order to slow flavonoid and carotenoid degradation. As demonstrated by the multiple transcription factors that were differentially expressed in the yellow- and white-fleshed varieties, it is clear that the regulation of peach and nectarine colouration is a complex process. Furthermore, we also identified several other genes that are potentially related to fruit colouration. Thus, our results provide a valuable advancement in the elucidation of the molecular basis of flesh colouration in nectarine
Characterization of the ABC Transporter G Subfamily in Pomegranate and Function Analysis of PgrABCG14
ATP-binding cassette subfamily G (ABCG) proteins play important roles in plant growth and development by transporting metabolites across cell membranes. To date, the genetic characteristics and potential functions of pomegranate ABCG proteins (PgrABCGs) have remained largely unknown. In this study, we found that 47 PgrABCGs were divided into five groups according to a phylogenetic analysis; groups I, II, III, and IV members are half-size proteins, and group V members are full-size proteins. PgrABCG14, PgrABCG21, and PgrABCG47 were highly expressed in the inner seed coat but had very low expression levels in the outer seed coat, and the expression levels of these three PgrABCG genes in the inner seed coats of hard-seeded pomegranate ‘Dabenzi’ were higher than those of soft-seeded pomegranate ‘Tunisia’. In addition, the expression of these three PgrABCG genes was highly correlated with the expression of genes involved in lignin biosynthesis and hormone signaling pathways. The evolution of PgrABCG14 presents a highly similar trend to the origin and evolution of lignin biosynthesis during land plant evolution. Ectopic expression of PgrABCG14 in Arabidopsis promoted plant growth and lignin accumulation compared to wild type plants; meanwhile, the expression levels of lignin biosynthesis-related genes (CAD5, C4H, and Prx71) and cytokinin response marker genes (ARR5 and ARR15) were significantly upregulated in transgenic plants, which suggests the potential role of PgrABCG14 in promoting plant growth and lignin accumulation. Taken together, these findings not only provide insight into the characteristics and evolution of PgrABCGs, but also shed a light on the potential functions of PgrABCGs in seed hardness development