29 research outputs found

    Ferric Iron Nanoparticle Formation Mediated By Negatively Charged Polypeptides

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    The creation of magnetite particles by magnetotactic bacteria has been of great interest for a number of years. Previous studies have shown that magnetite nanocrystals have been synthesized in the presence of recombinant Mms6 protein. Mms6 plays a vital role in the biomineralization of bacterial magnetite nanocrystals. The objective of this research is to determine the effect of functional group type on size and shape of magnetic nanoparticles formed by biomineralization. Control over the size of nanoparticles is paramount. Use of nanoparticles as contrast agents in MRI is advantageous, as they are small enough to be localized in desired region by applying local magnetic fields. Sequences VA-Mms6, VA1, VA2, and VA3 were designed with modifications in the functional groups Mms6 sequence. Solutions of peptide were mixed with ferric and ferro salts and allowed to interact under inert atmosphere. The nanoparticles formed are examined under SEM and TEM and compared for differences. The SEM and TEM images of nanoparticles produced with the aid of the above peptides had similarity to those produced in the magnetotactic bacteria. However, discrete particles with a narrower size range were produced using the peptide VA2. XPS, AFM, DLS and MFM were also done on the synthesized nanoparticles. The results were in good agreement when compared to those with a standard control sample of magnetite nanoparticles. Use of peptides with different functional groups may provide a unique route to produce uniform magnetite nanocrystals with definite control of morphology

    Novel Mannich bases bearing pyrazolone moiety. Synthesis, characterization and electrochemical studies

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    The present investigation describes a series of new {4-[3-Methyl-5-oxo-4-(4|-substituted phenyl hydrazono)-4,5-dihydro-pyrazol-1-yl]-phenoxy}-acetic acid (2-oxo-1-piperidine-1-ylmethyl-1,2-dihydro–indol-3-ylidene)-hydrazides synthesized by the Mannich reaction of {4-[3-Methyl-5-oxo-4-(4|-substituted phenyl hydrazono)-4,5-dihydro-pyrazol-1-yl]-phenoxy}-acetic acid (2-oxo-1,2-dihydro-indol-3-ylidene)-hydrazide with aqueous formaldehyde and a solution of piperidine in dimethylformamide. These novel Mannich bases were characterized by elemental analysis, IR, 1H NMR and mass spectral data. Electrochemical behavior of these compounds were studied by two techniques namely polarography and cyclic voltammetry. The results from both the techniques were compared and the reduction mechanism in acidic as well as basic medium was proposed

    Generative Design in Minecraft (GDMC), Settlement Generation Competition

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    This paper introduces the settlement generation competition for Minecraft, the first part of the Generative Design in Minecraft challenge. The settlement generation competition is about creating Artificial Intelligence (AI) agents that can produce functional, aesthetically appealing and believable settlements adapted to a given Minecraft map - ideally at a level that can compete with human created designs. The aim of the competition is to advance procedural content generation for games, especially in overcoming the challenges of adaptive and holistic PCG. The paper introduces the technical details of the challenge, but mostly focuses on what challenges this competition provides and why they are scientifically relevant.Comment: 10 pages, 5 figures, Part of the Foundations of Digital Games 2018 proceedings, as part of the workshop on Procedural Content Generatio

    Epidemiology of non-alcoholic fatty liver disease and risk of hepatocellular carcinoma progression

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    Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. Its incidence has grown alongside the increasing global prevalence of type 2 diabetes, obesity, and metabolic syndrome. The risk of progression to hepatocellular carcinoma for nonalcoholic steatohepatitis patients over 5 years is 8%, and despite targeted and immunotherapy treatment advances, HCC maintains a bleak 5-year survival of 19%. NAFLD’s primary risk factors are components of metabolic syndrome as well as possible sleep disturbances. NAFLD is most common among men 50-60 years of age, though incidence in women catches up after menopause. In the US, Hispanics are most likely to develop NAFLD and African Americans least likely, in part due to the prevalence of the PNPLA3 gene variant. With NAFLD risk factors especially prevalent in underserved populations and developing nations, public health interventions, earlier diagnosis, and novel treatments could curb the growing disease burden

    Synthesis and Antimicrobial Evaluation of Certain Novel Thiazoles

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    Purpose: This article makes an attempt to synthesize certain compounds containing thiazole and imidazole moieties and screen for the antimicrobial properties. Methods: The novel compounds synthesized were characterized by elemental analysis, IR and 1HNMR spectral data. The antimicrobial activity of novel compounds was evaluated by cup plate method. Results: The compound p-t showed more antibacterial activity than that of the standard. p-hp and p-as showed considerable antibacterial activity. p-t demonstrated higher antifungal activity than that of the standard while p-hp and p-as showed considerable antifungal activity. Conclusion: The antimicrobial activity studies were conducted on certain selected bacteria and fungi. In each case antimicrobial activity of the compounds was compared with that of standards. p-t, p-hp, p-np, p-cp, p-ts and p-as showed considerable antimicrobial activity

    A NEW SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF TRACE AMOUNTS OF TITANIUM(IV)

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    Abstract. A new, rapid, simple, precise and extraction-free spectrophotometric method is proposed for the micro determination of titanium(IV) employing N'-(2-hydroxybenzylidene)-3-oxobutanehydrazide as a reagent. Under the optimum conditions established, the absorbance was found to increase linearly with the concentration of titanium(IV) i

    Imaging the real space structure of the spin fluctuations in an iron-based superconductor

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    Spin fluctuations are a leading candidate for the pairing mechanism in high temperature superconductors, supported by the common appearance of a distinct resonance in the spin susceptibility across the cuprates, iron-based superconductors and many heavy fermion materials1. The information we have about the spin resonance comes almost exclusively from neutron scattering. Here we demonstrate that by using low-temperature scanning tunneling microscopy and spectroscopy we can characterize the spin resonance in real space. We establish that inelastic tunneling leads to the characteristic "dip-hump" feature seen in tunneling spectra in high temperature superconductors and that this feature arises from excitations of the spin fluctuations. Spatial mapping of this feature near defects allows us to probe non-local properties of the spin susceptibility and to image its real space structure.Publisher PDFPeer reviewe

    Impact of Iron-site defects on Superconductivity in LiFeAs

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    PW acknowledges funding from the MPG-UBC center and financial support from EPSRC (EP/I031014/1).In conventional s-wave superconductors, only magnetic impurities exhibit impurity bound states, whereas for an s order parameter they can occur for both magnetic and non-magnetic impurities. Impurity bound states in superconductors can thus provide important insight into the order parameter. Here, we present a combined experimental and theoretical study of native and engineered iron-site defects in LiFeAs. Detailed comparison of tunneling spectra measured on impurities with spin fluctuation theory reveals a continuous evolution from negligible impurity bound state features for weaker scattering potential to clearly detectable states for somewhat stronger scattering potentials. All bound states for these intermediate strength potentials are pinned at or close to the gap edge of the smaller gap, a phenomenon that we explain and ascribe to multi-orbital physics.PostprintPeer reviewe
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