1,462 research outputs found

    Anion recognition and sensing of ruthenium(II) and cobalt(II) sulfonamido complexes

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    A series of artificial receptors, based on a sulfonamido system, have been designed and synthesized. The interaction of these receptors with biologically important anions was determined by UV-vis, (1)H NMR titration and electrochemical experiments. Results indicate that these receptors show high recognition abilities for fluoride (F(-)) or acetate (AcO(-)), moderate affinities for dihydrogen phosphate (H(2)PO(4)(-)) or hydroxyl (OH(-)) and almost no affinities for chloride (Cl(-)), bromide (Br(-)) or iodide (I(-)). (1)H NMR titration shows that the interaction between the receptors and anions depends on the hydrogen-bond formation. The Co(III)/Co(II) redox signals of receptor 3 and 4 disappear gradually when the fluoride or acetate anions are added. Moreover, visual color changes accompany guest binding, enabling this system to act as colorimetric anion sensors. The colorimetric properties of these sensors are ascribed to the hydrogen-bond formation and the colorimetric group quinoxaline

    Effects of L-arginine on intestinal development and endogenous arginine-synthesizing enzymes in neonatal pigs

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    This study aimed to investigate the effects of dietary L-arginine supplementation on the intestinal development of neonatal piglets and the underlying mechanisms. 36 neonatal piglets were randomly allocated into three diet groups: control group (supplemented with 0% L-arginine), 0.4 and 0.8% Larginine groups. When compared with the control, dietary supplementation with L-arginine decreased (P<0.05) blood urea nitrogen (BUN), and improved (P<0.05) serum T3 and insulin level of the piglets on day 11. Arginine and its metabolites (citrulline and ornithine) were elevated, additionally, dietary supplementation with 0.8% L-arginine markedly enhanced jejunal villus height, villus area on day 11 and D-xylose absorption rate on day 19. Dietary supplementation with 0.8% L-arginine increased (P<0.05) activities of maltose and lactose on day 18, respectively. This effect correlated with profound change in enzyme activities as inducible nitric oxide synthetase (iNOS), glutamine synthetase (GS) and ornithine decarboxylase (ODC) were elevated on day 18. The concentrations of spermine was increased (P<0.05) by L-arginine supplementation on day 18. These results collectively suggest that dietary  Larginine supplementation improves protein synthesis and intestinal development of the neonatal pigs, the underlying mechanism includes dietary L-arginine supplementation which regulated the productions of intestinal polyamine in jejunum, and stimulated endogenous arginine-synthesizing enzymes in neonatal piglets.Key words: Neonatal pig, L-arginine, intestinal development, arginine-synthetases

    Construction and evaluation of rats’ tolerogenic dendritic cells (DC) induced by NF-κB Decoy method

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    Aims: To construct and evaluate rats’ tolerogenic dendritic cells (DC) through induction by NF-κB Decoy method.Methods: GM-CSF and IL-4 were used to transform rats’s monocytes into DC, and DC were stimulated with LPS, NF-κB Decoy ODN, and loaded with Bovine TypeⅡCollagen. The following methods were employed to phenotype DC: 1) Observation of cell morphology; 2) Evaluation of cell viability using trypan blue staining; 3) Purity determination of DC through detection of specific markers OX-62; 4) Evaluation of mature state of DC via the determination of the expression of CD80 and CD86; 5) Determination of stimulation capability towards the proliferation of lymphocyte and the secretion of INF-r and IL-10.Results: The activity of DC was more than 92%, and the expression of OX-62 was more than 70%. Most of DC exhibited the phenotype of CD80+/CD86-. Compared with control group and LPS-stimulation group, the less mature adhered cells and hairlike DC were observed in NF-κB decoy group. Significant reduction (p<0.05) was observed for the positive expression and extension of CD80 and CD86 in cell surface. After loaded with calf type II collagen, the low expression of CD80 and CD86 remains to be existed. The stimulation capability of DC towards lymphocyte in NF-κB decoy group was lower than that in control group (p<0.05) and LPS stimulation group (p<0.05).Conclusion: NF-κB Decoy ODN method can be successfully applied for construct rats’ tolerogenic dendritic cells (DC) with stable morphology and phenotype. The tolerogenic DC exhibited immature immune phenotype, and low capability to stimulate lymphocytes.Keywords: dendritic cells (DC), NF-κB Decoy ODN, calf type II collage

    Controlled motion of electrically neutral microparticles by pulsed direct current

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    A controlled motion of electrically neutral microparticles in a conductive liquid at high temperatures has not yet been realized under the uniform direct electric current field. We propose a simple method, which employs pulsed direct current to a conductive liquid metal containing low-conductivity objects at high temperature. The electric current enables the low-conductivity particles to pass from the centre towards the various surfaces of the high-conductivity liquid metal. Most interestingly, the directionality of microparticles can be controlled and their speed can be easily regulated by adjusting pulsed current density. We find that the movement may arise from the configuration of electrical domains which generates a driving force which exceeds the force of gravity and viscous friction. All of these features are of potential benefit in separating the particles of nearly equal density but distinctly different electrical conductivities, and also offer considerable promise for the precise and selective positioning of micro-objects or the controlled motion of minute quantities of surrounding fluids

    Prediction of migratory routes of the invasive fall armyworm in eastern China using a trajectory analytical approach

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record BACKGROUND: The fall armyworm (FAW), an invasive pest from the Americas, is rapidly spreading through the Old World, and has recently invaded the Indochinese Peninsula and southern China. In the Americas, FAW migrates from winter-breeding areas in the south into summer-breeding areas throughout North America where it is a major pest of corn. Asian populations are also likely to evolve migrations into the corn-producing regions of eastern China, where they will pose a serious threat to food security. RESULTS: To evaluate the invasion risk in eastern China, the rate of expansion and future migratory range was modelled by a trajectory simulation approach, combined with flight behavior and meteorological data. Our results predict that FAW will migrate from its new year-round breeding regions into the two main corn-producing regions of eastern China (Huang-Huai-Hai Summer Corn and Northeast Spring Corn Regions), via two pathways. The western pathway originates in Myanmar and Yunnan, and FAW will take four migration steps (i.e. four generations) to reach the Huang-Huai-Hai Region by July. Migration along the eastern pathway from Indochina and southern China progresses faster, with FAW reaching the Huang-Huai-Hai Region in three steps by June and reaching the Northeast Spring Region in July. CONCLUSION: Our results indicate that there is a high risk that FAW will invade the major corn-producing areas of eastern China via two migration pathways, and cause significant impacts to agricultural productivity. Information on migration pathways and timings can be used to inform integrated pest management strategies for this emerging pest.Biotechnology & Biological Sciences Research Council (BBSRC)CABI Bioscienc
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