Simultaneous dual-frequency radio observations of S5 0716+714: A search for intraday variability with the Korean VLBI Network

This study aims to search for the existence of intraday variability (IDV) of BL Lac object S5 0716+714 at high radio frequencies for which the interstellar scintillation effect is not significant. Using the 21-meter radio telescope of the Korean VLBI Network (KVN), we present results of multi-epoch simultaneous dual-frequency radio observations. Single-dish observations of S5 0716+714 were simultaneously conducted at 21.7 GHz (K-band) and 42.4 GHz (Q-band), with a high cadence of 30-60 minute intervals.We observed four epochs between December 2009 and June 2010. Over the whole set of observation epochs, S5 0716+714 showed significant inter-month variations in flux density at both the K- and Q-bands, with modulation indices of approximately 19% for the K-band and approximately 36% for the Q-band. In all epochs, no clear intraday variability was detected at either frequency. The source shows monotonic flux density increase in epochs 1 and 3 and monotonic flux density decrease in epochs 2 and 4. In the flux density increasing phases, the flux densities at the Q-band increase more rapidly. In the decreasing phase, no significant flux density difference is seen at the two frequencies. The situation could be different close to flux density peaks that we did not witness in our observations. We find an inverted spectrum with mean spectral indices of -0.57+-0.13 in epoch 1 and -0.15+-0.11 in epoch 3. On the other hand, we find relatively steep indices of +0.24+-0.14 and +0.17+-0.18 in epochs 2 and 4, respectively. We conclude that the frequency dependence of the variability and the change of the spectral index are caused by source-intrinsic effects rather than by any extrinsic scintillation effect.Comment: 6 pages and 4 figures and 4 table

Improvement of Information Transfer Rates Using a Hybrid EEG-NIRS Brain-Computer Interface with a Short Trial Length: Offline and Pseudo-Online Analyses

Electroencephalography (EEG) and near-infrared spectroscopy (NIRS) are non-invasive neuroimaging methods that record the electrical and metabolic activity of the brain, respectively. Hybrid EEG-NIRS brain-computer interfaces (hBCIs) that use complementary EEG and NIRS information to enhance BCI performance have recently emerged to overcome the limitations of existing unimodal BCIs, such as vulnerability to motion artifacts for EEG-BCI or low temporal resolution for NIRS-BCI. However, with respect to NIRS-BCI, in order to fully induce a task-related brain activation, a relatively long trial length (≥10 s) is selected owing to the inherent hemodynamic delay that lowers the information transfer rate (ITR; bits/min). To alleviate the ITR degradation, we propose a more practical hBCI operated by intuitive mental tasks, such as mental arithmetic (MA) and word chain (WC) tasks, performed within a short trial length (5 s). In addition, the suitability of the WC as a BCI task was assessed, which has so far rarely been used in the BCI field. In this experiment, EEG and NIRS data were simultaneously recorded while participants performed MA and WC tasks without preliminary training and remained relaxed (baseline; BL). Each task was performed for 5 s, which was a shorter time than previous hBCI studies. Subsequently, a classification was performed to discriminate MA-related or WC-related brain activations from BL-related activations. By using hBCI in the offline/pseudo-online analyses, average classification accuracies of 90.0 ± 7.1/85.5 ± 8.1% and 85.8 ± 8.6/79.5 ± 13.4% for MA vs. BL and WC vs. BL, respectively, were achieved. These were significantly higher than those of the unimodal EEG- or NIRS-BCI in most cases. Given the short trial length and improved classification accuracy, the average ITRs were improved by more than 96.6% for MA vs. BL and 87.1% for WC vs. BL, respectively, compared to those reported in previous studies. The suitability of implementing a more practical hBCI based on intuitive mental tasks without preliminary training and with a shorter trial length was validated when compared to previous studies

How cancer cells remodel lipid metabolism: strategies targeting transcription factors

Reprogramming of lipid metabolism has received increasing recognition as a hallmark of cancer cells because lipid dysregulation and the alteration of related enzyme profiles are closely correlated with oncogenic signals and malignant phenotypes, such as metastasis and therapeutic resistance. In this review, we describe recent findings that support the importance of lipids, as well as the transcription factors involved in cancer lipid metabolism. With recent advances in transcription factor analysis, including computer-modeling techniques, transcription factors are emerging as central players in cancer biology. Considering the limited number and the crucial role of transcription factors associated with lipid rewiring in cancers, transcription factor targeting is a promising potential strategy for cancer therapy.This work was supported by National Research Foundation of Korea (No.2019R1A2C2083886, 2018R1A5A2025964)

Simultaneous Acquisition of EEG and NIRS during Cognitive Tasks for an Open Access Dataset

We provide an open access multimodal brain-imaging dataset of simultaneous electroencephalography (EEG) and near-infrared spectroscopy (NIRS) recordings. Twenty-six healthy participants performed three cognitive tasks: 1) n-back (0-, 2- and 3-back), 2) discrimination/selection response task (DSR) and 3) word generation (WG) tasks. The data provided includes: 1) measured data, 2) demographic data, and 3) basic analysis results. For n-back (dataset A) and DSR tasks (dataset B), event-related potential (ERP) analysis was performed, and spatiotemporal characteristics and classification results for “target” vs. “non-target” (dataset A) and symbol “O” vs. symbol “X” (dataset B) are provided. Time-frequency analysis was performed to show the EEG spectral power to differentiate the task-relevant activations. Spatiotemporal characteristics of hemodynamic responses are also shown. For the WG task (dataset C), the EEG spectral power and spatiotemporal characteristics of hemodynamic responses are analyzed, and the potential merit of hybrid EEG-NIRS BCIs was validated with respect to classification accuracy. We expect that the dataset provided will facilitate performance evaluation and comparison of many neuroimaging analysis techniques

Enhancement of carbamazepine removal rate using Tetradesmus obliquus KNUA061 and NaOCl and utilization of the resulting biomass

Pharmaceutical and personal care products (PPCPs) are discharged into receiving water bodies mainly from sewage treatment plants. Due to the inefficient removal in conventional wastewater treatment facilities, PPCPs have become a major concern to aquatic ecosystems, water quality, and public health worldwide since they cause harmful effects on aquatic life and human even at low doses. Among the PPCPs, carbamazepine (CBZ) is one of the most commonly prescribed anticonvulsant drugs and consumed more than 1,000 tons per year. Due to its structural complexity, CBZ is known as recalcitrant compound highly stable during wastewater treatment. Consequently, it has become one of the most frequently detected pharmaceuticals in waste water, surface water, and even drinking water. In this study, Korean indigenous microalgae strains were tested as eco-friendly and cost-effective solutions for CBZ removal. Based on the preliminary biological CBZ degradation tests, Tetradesmus obliquus KNUA061 demonstrating the best CBZ removal rate was selected for further experiments. In order to increase strain KNUA061's CBZ removal efficiency, NaOCl, which is widely accepted in the water purification process, was used as an additional stimulus to induce stress conditions. At around 20 μg L−1 CBZ, addition of 1.0 mg NaOCl resulted in approximately 20% of removal rate increase without suppressing cells growth. Roughly 90% of CBZ remained its original form and the composition of the transformed secondary metabolites was less than 10% during the biodegradation process by the microalga. Based on the results of the antioxidant enzyme activities, degree of lipid oxidation, and amino acid contents, it was concluded that the redox-defence system in microalgal cells may have been activated by the NaOCl treatment. Biomass analysis results showed that higher heating value (HHV) of strain KNUA061 biomass was higher than those of lignocellulosic energy crops suggesting that it could be utilized as a possible renewable energy source. Even though its biodiesel properties were slightly below the international standards due to the high PUFA contents, the biodiesel produced from T. obliquus KNUA061 could be used as a blending resource for transportation fuels. It was also determined that the microalgal biomass has acceptable feasibility as a sustainable dietary supplement feedstock due to its high essential amino acid contents

TSLP Induces Mast Cell Development and Aggravates Allergic Reactions through the Activation of MDM2 and STAT6

Thymic stromal lymphopoietin (TSLP) is known to promote T helper type 2 cell–associated inflammation. Mast cells are major effector cells in allergic inflammatory responses. We noted that the population and maturation of mast cells were reduced in TSLP-deficient mice (TSLP-/-). Thus, we hypothesized that TSLP might affect mast cell development. We found that TSLP induced the proliferation and differentiation of mast cells from bone marrow progenitors. TSLP-induced mast cell proliferation was abolished by depletion of mouse double minute 2 (MDM2) and signal transducers and activators of transcription 6 (STAT6), as an upstream activator of MDM2. TSLP-/-, in particular, had a considerable deficit in the expression of MDM2 and STAT6. Also, the TSLP deficiency attenuated mast cell–mediated allergic reactions through the downregulation of STAT6 and MDM2. In an antibody microarray chip analysis, MDM2 expression was increased in atopic dermatitis patients. These observations indicate that TSLP is a factor for mast cell development, and that it aggravates mast cell–mediated immune responses

Preventive effects of Korean red ginseng on experimentally induced colitis and colon carcinogenesis

© 2020 Center for Food and Biomolecules, National Taiwan UniversityKorean Red Ginseng (KRG) exerts chemopreventive effects on experimentally induced carcinogenesis through multiple mechanisms. In this study, we investigated effects of KRG on dextran sulfate sodium (DSS)-induced colitis and azoxymethane (AOM) plus DSS-induced colon carcinogenesis in mice. Male C57BL/6J mice were fed diet containing 1% KRG or a standard diet throughout the experiment. The mouse colitis was induced by administration of 3% DSS in drinking water for 1 week. DSS caused body weight loss, diarrhea, rectal bleeding and colon length shortening, and all these symptoms were ameliorated by KRG treatment. KRG inhibited DSS-induced expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) by suppressing activation of nuclear factor-kappa B (NF-κB) and signal transducer and activation of transcription 3 (STAT3). In another experiment, colon carcinogenesis was initiated by single intraperitoneal injection of AOM (10 mg/kg) and promoted by 2% DSS in drinking water. KRG administration relieved the symptoms of colitis and reduced the incidence, the multiplicity and the size of colon tumor. The up-regulation of COX-2, iNOS, c-Myc and Cyclin D1 by AOM plus DSS was attenuated in KRG fed mice which was associated with suppression of NF-κB and STAT3 activation. These results suggest that KRG is a potential candidate for chemoprevention of inflammation-associated cancer in the colon.