No abstract

Quercetin is an active nutraceutical element that is found in a variety of foods, vegetables, fruits, and other products. Due to its antioxidant properties, quercetin is a flexible functional food that has broad protective effects against a wide range of infectious and degenerative disorders. As a result, research is required on food-contact surfaces (rubber (R) and hand gloves (HG)) that can lead to cross-contamination. In this investigation, the inhibitory effects of quercetin, an antioxidant and antibacterial molecule, were investigated at sub-MIC (125; 1/2, 62.5; 1/4, and 31.25; 1/8 MIC, μg/mL) against Salmonella Typhimurium on surfaces. When quercetin (0–125 μg/mL) was observed on R and HG surfaces, the inhibitory effects were 0.09–2.49 and 0.20–2.43 log CFU/cm2, respectively (p < 0.05). The results were confirmed by field emission scanning electron microscopy (FE-SEM), because quercetin inhibited the biofilms by disturbing cell-to-cell connections and inducing cell lysis, resulting in the loss of normal cell morphology, and the motility (swimming and swarming) was significantly different at 1/4 and 1/2 MIC compared to the control. Quercetin significantly (p < 0.05) suppressed the expression levels of virulence and stress response (rpoS, avrA, and hilA) and quorum-sensing (luxS) genes. Our findings imply that plant-derived quercetin could be used as an antibiofilm agent in the food industry to prevent S. Typhimurium biofilm formation.

Atopic dermatitis (AD), with the prevalence rate of around 10 to 15%, is characterized by an intensely pruritic skin lesions with typical distribution and morphology. Recently, AD is divided into extrinsic type (ADe) and intrinsic type (ADi) according to the laboratory findings and associated diseases. ADe is well-known for high IgE level, positive response to food-or aero-allergens, whereas ADi has clinically similar skin lesions and distribution patterns of AD with normal serum IgE levels, negative in vitro test for environmental or food allergens and without associated atopic diseases. To instrumentally evaluate the differences of skin involvement and functions between ADi and ADe, we checked the transepidermal water loss (TEWL), capacitance and pH in both types of childhood AD and age-matched control. The proportion of ADi was around 20% in all AD patients (10/51). Our experiment suggested possible differences between ADi and ADe. Antecubital fossa is a famous involvement site of childhood type of AD, where both types of AD patients showed higher TEWL and decreased capacitance. ADe patients showed increased TEWL in all sites and lower hydration in 4 sites, whereas ADi patients showed no significant differences of TEWL and hydration in forehead, cheek, and back of leg.

The Korean VLBI Network (KVN) is a new mm-VLBI dedicated array with capability for simultaneous observations at multiple frequencies, up to 129 GHz.The innovative multi-channel receivers present significant benefits for astrometric measurements in the frequency domain. The aim of this work is to verify the astrometric performance of the KVN using a comparative study with the VLBA, a well established instrument. For that purpose, we carried out nearly contemporaneous observations with the KVN and the VLBA, at 14/7 mm, in April 2013. The KVN observations consisted of simultaneous dual frequency observations, while the VLBA used fast frequency switching observations. We used the Source Frequency Phase Referencing technique for the observational and analysis strategy. We find that having simultaneous observations results in a superior performance for compensation of all atmospheric terms in the observables, in addition to offering other significant benefits for astrometric analysis.We have compared the KVN astrometry measurements to those from the VLBA.We find that the structure blending effects introduce dominant systematic astrometric shifts and these need to be taken into account. We have tested multiple analytical routes to characterize the impact of the low resolution effects for extended sources in the astrometric measurements. The results from the analysis of KVN and full VLBA datasets agree within 2-σ of the thermal error estimate.We interpret the discrepancy as arising from the different resolutions. We find that the KVN provides astrometric results with excellent agreement, within 1-σ, when compared to a VLBA configuration which has a similar resolution. Therefore this comparative study verifies the astrometric performance of KVN using SFPR at 14/7 mm, and validates the KVN as an astrometric instrument. Subject headings: Astrometry -techniques: interferometric -quasars: individual (OJ287, 0854+213)GHz, along with KVN observations using a similar configuration, both carried out in April 2013. The VLBA observations were carried out using fast frequency switching between both bands, while the KVN used simultaneous dual frequency observations. This study will serve to deepen the understanding on the limitations imposed by the fast frequency switching observing mode (i.e. with the VLBA), and the benefits derived from simultaneous dual frequency simultaneous observations with the multi-channel receivers in the KVN. The driver for this is to investigate whether to equip global baselines with KVN-like systems or more conventional fast frequency-switching systems.The interest and basis of the SFPR method have been described in detail in other publications ; most recently, the application to spectral line observations of H 2 O and SiO masers in evolved stars, with a non integer frequency ratio, is presented in Dodson et al. (2014). In summary, the SFPR technique provides at mm-wavelengths the benefits that conventional PR has in the cm-wavelength regime, where the moderate tropospheric phase fluctuations can be match...

Oxygen-rich Asymptotic Giant Branch (AGB) stars can be intense emitters of SiO (v=1 and 2, J=1→0) and H 2 O maser lines at 43 and 22 GHz, respectively. VLBI observations of the maser emission provide a unique tool to probe the innermost layers of the circumstellar envelopes in AGB stars. Nevertheless, the difficulties in achieving astrometrically aligned H 2 O and v=1 and v=2 SiO maser maps have traditionally limited the physical constraints that can be placed on the SiO maser pumping mechanism. We present phase referenced simultaneous spectral-line VLBI images for the SiO v=1 and v=2, J=1→0, and H 2 O maser emission around the AGB star R LMi, obtained from the Korean VLBI Network (KVN). The simultaneous multi-channel receivers of the KVN offer great possibilities for astrometry in the frequency domain. With this facility we have produced images with bona-fide absolute astrometric registration between high frequency maser transitions of different species to provide the positions of the H 2 O maser emission, and the centre of the SiO maser emission, and hence reducing the uncertainty in the proper motion for R LMi by an order of magnitude over that from Hipparcos. This is the first successful demonstration of source frequency phase referencing for mm-VLBI spectral-line observations and also where the ratio between the frequencies is not an integer.

Evidence accumulation has been the core component in recent development of perceptual and value-based decision-making theories. Most studies have focused on the evaluation of evidence between alternative options. What remains largely unknown is the process that prepares evidence: how may the decision-maker sample different sources of information sequentially, if they can only sample one source at a time? Here we propose a theoretical framework in prescribing how different sources of information should be sampled to facilitate the decision process: beliefs for different noisy sources are updated in a Bayesian manner and participants can proactively allocate resource for sampling (i.e., saccades) among different sources to maximize the information gain in such process. We show that our framework can account for human participants' actual choice and saccade behavior in a two-alternative value-based decision-making task. Moreover, our framework makes novel predictions about the empirical eye movement patterns.

We report simultaneous multi-frequency observing performance at 22 and 43 GHz of the 21-m shaped-Cassegrain radio telescopes of the Korean VLBI Network (KVN). KVN is the first millimeter-dedicated VLBI network in Korea having a maximum baseline length of 480 km. It currently operates at 22 and 43 GHz and planed to operate in four frequency bands, 22, 43, 86, and 129 GHz. The unique quasioptics of KVN enable simultaneous multi-frequency observations based on efficient beam filtering and accuarate antenna-beam alignment at 22 and 43 GHz. We found that the offset of the beams is within < 5 arcseconds over all pointing directions of antenna. The dual polarization, cooled HEMT receivers at 22 and 43 GHz result in receiver noise temperatures less than 40 K at 21.

Balancing exploration and exploitation is a fundamental aspect of decision-making. It remains unknown whether people are close to optimal in striking this balance, and if not, how exactly their behavior deviates from optimality. Many existing paradigms are not ideally suited to answer this question, as they contain complexities such as non-stationary environments, stochasticity under exploitation, and reward distributions that are unknown to participants. Here, we introduce a task without such complexities, in which the optimal policy is to start off exploring and to switch to exploitation at most once in each sequence of decisions. The behavior of 49 laboratory and 143 online participants deviated both qualitatively and quantitatively from the optimal policy, even when allowing for bias and decision noise. Instead, people seem to follow a suboptimal rule in which they switch from exploration to exploitation when the highest reward so far exceeds a certain threshold. Moreover, we show that this threshold decreases approximately linearly with the proportion of the sequence that remains, suggesting a novel temporal ratio law. Finally, we find evidence for "sequencelevel" variability which is shared across all decisions in the same sequence. Our results provide a new perspective on the explore-exploit dilemma, and emphasize the importance of examining sequencelevel strategies and their variability when studying sequential decision-making..