476 research outputs found
Article Heteroaryl Chalcones: Design, Synthesis, X-ray Crystal Structures and Biological Evaluation
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Views from within a narrative : Evaluating long-term human-robot interaction in a naturalistic environment using open-ended scenarios
Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. Date of acceptance: 16/06/2014This article describes the prototyping of human–robot interactions in the University of Hertfordshire (UH) Robot House. Twelve participants took part in a long-term study in which they interacted with robots in the UH Robot House once a week for a period of 10 weeks. A prototyping method using the narrative framing technique allowed participants to engage with the robots in episodic interactions that were framed using narrative to convey the impression of a continuous long-term interaction. The goal was to examine how participants responded to the scenarios and the robots as well as specific robot behaviours, such as agent migration and expressive behaviours. Evaluation of the robots and the scenarios were elicited using several measures, including the standardised System Usability Scale, an ad hoc Scenario Acceptance Scale, as well as single-item Likert scales, open-ended questionnaire items and a debriefing interview. Results suggest that participants felt that the use of this prototyping technique allowed them insight into the use of the robot, and that they accepted the use of the robot within the scenarioPeer reviewe
A putative lytic transglycosylase tightly regulated and critical for the EHEC type three secretion
Open reading frame l0045 in the pathogenic island of enterohemorrhagic Escherichia coli O157:H7 has been predicted to encode a lytic transglycosylase that is homologous to two different gene products encoded by the same bacteria at loci away from the island. To deduce the necessity of the presence in the island, we created an l0045-deleted strain of EHEC and observed that both the level of cytosolic EspA and that of the other type III secreted proteins in the media were affected. In a complementation assay, a low level-expressing L0045 appeared to recover efficiently the type III secretion (TTS). On the other hand, when l0045 was driven to express robustly, the intracellular levels of representative TTS proteins were severely suppressed. This suppression is apparently caused by the protein of L0045 per se since introducing an early translational termination codon abolished the suppression. Intriguingly, the authentic L0045 was hardly detected in all lysates of EHEC differently prepared while the same construct was expectedly expressed in the K-12 strain. A unique network must exist in EHEC to tightly regulate the presence of L0045, and we found that a LEE regulator (GrlA) is critically involved in this regulation
Comparison of Iron (III) Reducing Antioxidant Capacity (iRAC) and ABTS Radical Quenching Assays for Estimating Antioxidant Activity of Pomegranate
Pomegranate juice (PJ) has total antioxidant capacity which is reportedly higher compared to other common beverages. This short study aimed to assess the total antioxidant capacity of commercial PJ and pomegranate fruit using a newly described method for iron (III) reducing antioxidant capacity (iRAC) and to compare with the ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) and Folin–Ciocalteu assays. Commercial PJ, freeze-dried pomegranate, and oven-dried pomegranate were analyzed. The calibration results for iRAC were comparable to ABTS and Folin–Ciocalteu methods in terms of linearity (R2 > 0.99), sensitivity and precision. The total antioxidant capacity for PJ expressed as trolox equivalent antioxidant capacity (TEAC) was 33.4 ± 0.5 mM with the iRAC method and 36.3 ± 2.1 mM using the ABTS method. For dried pomegranates, total antioxidant capacity on a dry weight basis (DB) was 89–110 mmol/100 g DB or 76.0 ± 4.3 mmol/100 g DB using iRAC and ABTS methods, respectively. Freeze-dried pomegranate had 15% higher total antioxidant capacity compared with oven-dried pomegranate. In conclusion, pomegranate has high total antioxidant capacity as evaluated by the iRAC and ABTS methods, though variations occur due to the type of cultivar, geographic origin, processing and other factors. The study is relevant for attempts to refine food composition data for pomegranate and other functional food
The crystal structure of zwitterionic 2-{[(4-iminiumyl- 3-methyl-1,4-dihydropyridin-1-yl)methyl]- carbamoyl}benzoate hemihydrate
The asymmetric unit of the title compound, C15H15N3O3�0.5H2O, comprises two
2-{[(4-iminiumyl-3-methyl-1,4-dihydropyridin-1-yl)methyl]carbamoyl}benzoate
zwitterions (A and B) and a water molecule. The dihedral angles between the
pyridine and phenyl rings in the zwitterions are 53.69 (10) and 73.56 (11)� in A
and B, respectively. In the crystal, molecules are linked by N—H� � �O, O—
H� � �O, C—H� � �O and C—H� � ��(ring) hydrogen bonds into a three-dimensional
network. The crystal structure also features �–� interactions involving
the centroids of the pyridine and phenyl rings [centroid–centroid distances =
3.5618 (12) A ° in A and 3.8182 (14) A ° in B]
Interpretation of spin wave modes in Co/Ag nanodot arrays probed by broadband ferromagnetic resonance
Ferromagnetic resonance (FMR) and the measurement of magnetization dynamics
in general have become sophisticated tools for the study of magnetic systems at
the nanoscale. Nanosystems, such as the nanodots of this study, are
technologically important structures, which find applications in a number of
devices, such as magnetic storage and spintronic systems. In this work, we
describe the detailed investigation of cobalt nanodots with a 200 nm diameter
arranged in a square pitch array with a periodicity of 400 nm. Due to their
size, such structures can support standing spin-wave modes, which can have
complex spectral responses. To interpret the experimentally measured broadband
FMR, we are comparing the spectra of the nanoarray structure with the
unpatterned film of identical thickness. This allows us to obtain the general
magnetic properties of the system, such as the magnetization, g-factor and
magnetic anisotropy. We then use state-of-the-art simulations of the dynamic
response to identify the nature of the excitation modes. This allows us to
assess the boundary conditions for the system. We then proceed to calculate the
spectral response of our system, for which we obtained good agreement. Indeed,
our procedure provides a high degree of confidence, since we have interpreted
all the experimental data to a good degree of accuracy. In presenting this
work, we provide a full description of the theoretical framework and its
application to our system, and we also describe in detail the novel simulation
method used.Comment: 20 pages, 14 figure
Attention Drives Synchronization of Alpha and Beta Rhythms between Right Inferior Frontal and Primary Sensory Neocortex
The right inferior frontal cortex (rIFC) is specifically associated with attentional control via the inhibition of behaviorally irrelevant stimuli and motor responses. Similarly, recent evidence has shown that alpha (7–14 Hz) and beta (15–29 Hz) oscillations in primary sensory neocortical areas are enhanced in the representation of non-attended stimuli, leading to the hypothesis that allocation of these rhythms plays an active role in optimal inattention. Here, we tested the hypothesis that selective synchronization between rIFC and primary sensory neocortex occurs in these frequency bands during inattention. We used magnetoencephalography to investigate phase synchrony between primary somatosensory (SI) and rIFC regions during a cued-attention tactile detection task that required suppression of response to uncertain distractor stimuli. Attentional modulation of synchrony between SI and rIFC was found in both the alpha and beta frequency bands. This synchrony manifested as an increase in the alpha-band early after cue between non-attended SI representations and rIFC, and as a subsequent increase in beta-band synchrony closer to stimulus processing. Differences in phase synchrony were not found in several proximal control regions. These results are the first to reveal distinct interactions between primary sensory cortex and rIFC in humans and suggest that synchrony between rIFC and primary sensory representations plays a role in the inhibition of irrelevant sensory stimuli and motor responses.National Institutes of Health (U.S.) (Grant P41RR14075)National Institutes of Health (U.S.) (Grant K25MH072941)National Institutes of Health (U.S.) (Grant K01AT003459)National Institutes of Health (U.S.) (Grant K24AT004095)National Institutes of Health (U.S.) (Grant RO1-NS045130-01)National Institutes of Health (U.S.) (Grant T32GM007484)National Science Foundation (U.S.) (Grant 0316933)National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant DGE-1147470
Phosducin-like protein 1 is essential for G-protein assembly and signaling in retinal rod photoreceptors
G protein β subunits perform essential neuronal functions as part of G protein βγ and Gβ(5)-RGS (Regulators of G protein Signaling) complexes. Both Gβγ and Gβ(5)-RGS are obligate dimers that are thought to require the assistance of the cytosolic chaperonin CCT and a co-chaperone, phosducin-like protein 1 (PhLP1) for dimer formation. To test this hypothesis in vivo, we deleted the Phlp1 gene in mouse (Mus musculus) retinal rod photoreceptor cells and measured the effects on G protein biogenesis and visual signal transduction. In the PhLP1-depleted rods, Gβγ dimer formation was decreased 50-fold, resulting in a more than 10-fold decrease in light sensitivity. Moreover, a 20-fold reduction in Gβ(5) and RGS9-1 expression was also observed, causing a 15-fold delay in the shutoff of light responses. These findings conclusively demonstrate in vivo that PhLP1 is required for the folding and assembly of both Gβγ and Gβ(5)-RGS9
Branched Polymeric Media: Perchlorate-Selective Resins from Hyperbranched Polyethyleneimine
Perchlorate (ClO_4^–) is a persistent contaminant found in drinking groundwater sources in the United States. Ion exchange (IX) with selective and disposable resins based on cross-linked styrene divinylbenzene (STY-DVB) beads is currently the most commonly utilized process for removing low concentrations of ClO_4^– (10–100 ppb) from contaminated drinking water sources. However, due to the low exchange capacity of perchlorate-selective STY-DVB resins (0.5–0.8 eq/L), the overall cost becomes prohibitive when treating groundwater with higher concentration of ClO_4^– (e.g., 100–1000 ppb). In this article, we describe a new perchlorate-selective resin with high exchange capacity. This new resin was prepared by alkylation of branched polyethyleneimine (PEI) beads obtained from an inverse suspension polymerization process. Batch and column studies show that our new PEI resin with mixed hexyl/ethyl quaternary ammonium chloride exchange sites can selectively extract trace amounts of ClO_4^– from a makeup groundwater (to below detection limit) in the presence of competing ions. In addition, this resin has a strong-base exchange capacity of 1.4 eq/L, which is 1.75–2.33 times larger than those of commercial perchlorate-selective STY-DVB resins. The overall results of our studies suggest that branched PEI beads provide versatile and promising building blocks for the preparation of perchlorate-selective resins with high exchange capacity
Comparative effects of overproducing the AraC-type transcriptional regulators MarA, SoxS, RarA and RamA on antimicrobial drug susceptibility in Klebsiella pneumoniae
OBJECTIVES: In Klebsiella pneumoniae, overproduction of RamA and RarA leads to increased MICs of various antibiotics; MarA and SoxS are predicted to perform a similar function. We have compared the relative effects of overproducing these four AraC-type regulators on envelope permeability (a combination of outer membrane permeability and efflux), efflux pump and porin production, and antibiotic susceptibility in K. pneumoniae. METHODS: Regulators were overproduced using a pBAD expression vector. Antibiotic susceptibility was measured using disc testing. Envelope permeability was estimated using a fluorescent dye accumulation assay. Porin and efflux pump production was quantified using proteomics and validated using real-time quantitative RT–PCR. RESULTS: Envelope permeability and antibiotic disc inhibition zone diameters both reduced during overproduction of RamA and to a lesser extent RarA or SoxS, but did not change following overproduction of MarA. These effects were associated with overproduction of the efflux pumps AcrAB (for RamA and SoxS) and OqxAB (for RamA and RarA) and the outer membrane protein TolC (for all regulators). Effects on porin production were strain specific. CONCLUSIONS: RamA is the most potent regulator of antibiotic permeability in K. pneumoniae, followed by RarA then SoxS, with MarA having very little effect. This observed relative potency correlates well with the frequency at which these regulators are reportedly overproduced in clinical isolates
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