A minK-HERG complex regulates the cardiac potassium current I(Kr).

MinK is a widely expressed protein of relative molecular mass approximately 15K that forms potassium channels by aggregation with other membrane proteins. MinK governs ion channel activation, regulation by second messengers, and the function and structure of the ion conduction pathway. Association of minK with a channel protein known as KvLQT1 produces a voltage-gated outward K+ current (I[sK]) resembling the slow cardiac repolarization current (I[Ks]). HERG, a human homologue of the ether-a-go-go gene of the fruitfly Drosophila melanogaster, encodes a protein that produces the rapidly activating cardiac delayed rectifier (I[Kr]). These two potassium currents, I(Ks) and I(Kr), provide the principal repolarizing currents in cardiac myocytes for the termination of action potentials. Although heterologously expressed HERG channels are largely indistinguishable from native cardiac I(Kr), a role for minK in this current is suggested by the diminished I(Kr) in an atrial tumour line subjected to minK antisense suppression. Here we show that HERG and minK form a stable complex, and that this heteromultimerization regulates I(Kr) activity. MinK, through the formation of heteromeric channel complexes, is thus central to the control of the heart rate and rhythm

Analysis of argonaute 4-associated long non-coding RNA in arabidopsis thaliana sheds novel insights into gene regulation through RNA-directed DNA methylation

© 2017 by the authors. Licensee MDPI, Basel, Switzerland. RNA-directed DNA methylation (RdDM) is a plant-specific de novo DNA methylation mechanism that requires long noncoding RNA (lncRNA) as scaffold to define target genomic loci. While the role of RdDM in maintaining genome stability is well established, how it regulates protein-coding genes remains poorly understood and few RdDM target genes have been identified. In this study, we obtained sequences of RdDM-associated lncRNAs using nuclear RNA immunoprecipitation against ARGONAUTE 4 (AGO4), a key component of RdDM that binds specifically with the lncRNA. Comparison of these lncRNAs with gene expression data of RdDM mutants identified novel RdDM target genes. Surprisingly, a large proportion of these target genes were repressed in RdDM mutants suggesting that they are normally activated by RdDM. These RdDM-activated genes are more enriched for gene body lncRNA than the RdDM-repressed genes. Histone modification and RNA analyses of several RdDM-activated stress response genes detected increased levels of active histone mark and short RNA transcript in the lncRNA-overlapping gene body regions in the ago4 mutant despite the repressed expression of these genes. These results suggest that RdDM, or AGO4, may play a role in maintaining or activating stress response gene expression by directing gene body chromatin modification preventing cryptic transcription

Dynamic Conductance of Carbon Nanotubes

The dynamic conductance of carbon nanotubes was investigated using the nonequilibrium Green's function formalism within the context of a tight-binding model. Specifically, we have studied the ac response of tubes of different helicities, both with and without defects, and an electronic heterojunction. Because of the induced displacement currents, the dynamic conductance of the nanotubes differs significantly from the dc conductance displaying both capacitive and inductive responses. The important role of photon-assisted transport through nanotubes is revealed and its implications for experiments discussed.published_or_final_versio

The Exotic XYZ Charmonium-like Mesons

Charmonium, the spectroscopy of c\bar{c} mesons, has recently enjoyed a renaissance with the discovery of several missing states and a number of unexpected charmonium-like resonances. The discovery of these new states has been made possible by the extremely large data samples made available by the B-factories at the Stanford Linear Accelerator Center and at KEK in Japan, and at the CESR e^+e^- collider at Cornell. Conventional c\bar{c} states are well described by quark potential models. However, many of these newly discovered charmonium-like mesons do not seem to fit into the conventional c\bar{c} spectrum. There is growing evidence that at least some of these new states are exotic, i.e. new forms of hadronic matter such as mesonic-molecules, tetraquarks, and/or hybrid mesons. In this review we describe expectations for the properties of conventional charmonium states and the predictions for molecules, tetraquarks and hybrids and the various processes that can be used to produce them. We examine the evidence for the new candidate exotic mesons, possible explanations, and experimental measurements that might shed further light on the nature these states.Comment: 28 pages, 7 figures. Review for Ann Rev Nucl & Part Sc

Pharmacometabolomic mapping of early biochemical changes induced by sertraline and placebo.

In this study, we characterized early biochemical changes associated with sertraline and placebo administration and changes associated with a reduction in depressive symptoms in patients with major depressive disorder (MDD). MDD patients received sertraline or placebo in a double-blind 4-week trial; baseline, 1 week, and 4 weeks serum samples were profiled using a gas chromatography time of flight mass spectrometry metabolomics platform. Intermediates of TCA and urea cycles, fatty acids and intermediates of lipid biosynthesis, amino acids, sugars and gut-derived metabolites were changed after 1 and 4 weeks of treatment. Some of the changes were common to the sertraline- and placebo-treated groups. Changes after 4 weeks of treatment in both groups were more extensive. Pathway analysis in the sertraline group suggested an effect of drug on ABC and solute transporters, fatty acid receptors and transporters, G signaling molecules and regulation of lipid metabolism. Correlation between biochemical changes and treatment outcomes in the sertraline group suggested a strong association with changes in levels of branched chain amino acids (BCAAs), lower BCAAs levels correlated with better treatment outcomes; pathway analysis in this group revealed that methionine and tyrosine correlated with BCAAs. Lower levels of lactic acid, higher levels of TCA/urea cycle intermediates, and 3-hydroxybutanoic acid correlated with better treatment outcomes in placebo group. Results of this study indicate that biochemical changes induced by drug continue to evolve over 4 weeks of treatment and that might explain partially delayed response. Response to drug and response to placebo share common pathways but some pathways are more affected by drug treatment. BCAAs seem to be implicated in mechanisms of recovery from a depressed state following sertraline treatment

Infrared divergences and harmonic anomalies in the two-loop superstring effective action

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are creditedArticle funded by SCOAP3. This research is partially supported by STFC (Grant ST/L000415/1, String theory, gauge theory & duality

Research on Artificial Intelligence Ethics Based on the Evolution of Population Knowledge Base

The unclear development direction of human society is a deep reason for that it is difficult to form a uniform ethical standard for human society and artificial intelligence. Since the 21st century, the latest advances in the Internet, brain science and artificial intelligence have brought new inspiration to the research on the development direction of human society. Through the study of the Internet brain model, AI IQ evaluation, and the evolution of the brain, this paper proposes that the evolution of population knowledge base is the key for judging the development direction of human society, thereby discussing the standards and norms for the construction of artificial intelligence ethics.Comment: 12 pages, 6 figures,1 tabl

Enhanced Resolution in Nanoscale NMR via Quantum Sensing with Pulses of Finite Duration

The nitrogen-vacancy (N-V) color center in diamond is an enormously important platform for the development of quantum sensors, including for single-spin and single-molecule NMR. Detection of weak single-spin signals is greatly enhanced by repeated sequences of microwave pulses; in these dynamicaldecoupling techniques, the key control parameters swept in the experiment are the time intervals, τ, between pulses. Here, we show that, in fact, the pulse duration tp offers a powerful additional control parameter. While a non-negligible tp was previously considered simply a source of experimental error, we elucidate here the underlying quantum dynamics: we identify a landscape of quantum-state crossings which are usually inactive (closed) but may be controllably activated (opened) by adjusting tp from zero. We identify these crossings with recently observed but unexpected dips (so-called spurious dips) seen in the quantum coherence of the N-V spin. With this new understanding, both the position and the strength of these sharp features may be accurately controlled; they coexist with the usual broader coherence dips of short-duration microwave pulses, but their sharpness allows for higher-resolution spectroscopy with quantum diamond sensors, or their analogs

Enhanced Resolution in Nanoscale NMR via Quantum Sensing with Pulses of Finite Duration

The nitrogen-vacancy (N-V) color center in diamond is an enormously important platform for the development of quantum sensors, including for single-spin and single-molecule NMR. Detection of weak single-spin signals is greatly enhanced by repeated sequences of microwave pulses; in these dynamicaldecoupling techniques, the key control parameters swept in the experiment are the time intervals, τ, between pulses. Here, we show that, in fact, the pulse duration tp offers a powerful additional control parameter. While a non-negligible tp was previously considered simply a source of experimental error, we elucidate here the underlying quantum dynamics: we identify a landscape of quantum-state crossings which are usually inactive (closed) but may be controllably activated (opened) by adjusting tp from zero. We identify these crossings with recently observed but unexpected dips (so-called spurious dips) seen in the quantum coherence of the N-V spin. With this new understanding, both the position and the strength of these sharp features may be accurately controlled; they coexist with the usual broader coherence dips of short-duration microwave pulses, but their sharpness allows for higher-resolution spectroscopy with quantum diamond sensors, or their analogs