Constraint on Lorentz invariance violation from Vela pulsar

The High Energy Stereoscopic System (H.E.S.S) Collaboration reported the discovery of a novel radiation component from the Vela pulsar by their Cherenkov telescopes. It is of great importance that gamma rays with energies of at least 20~TeV are recorded unexpectedly. The H.E.S.S Collaboration argued that such results may challenge the state-of-the-art models for the high-energy emission of pulsars. We point out in this work that these results also provide a unique opportunity to constrain certain Lorentz invariance violation parameters, leading to the realization of studying Lorentz invariance violation by using gamma-ray pulsars. The Lorentz invariance violation scale is constrained at the level of $E_{\mathrm{LV,}1}> 1.66\times 10^{17} \rm GeV$ for the linear scenario, and $E_{\mathrm{LV,}2}>3.53\times 10^{10} \rm GeV$ for the quadratic scenario. We anticipate that digging into the detailed features of the data of the Vela pulsar and analyzing potentially more very-high-energy photon data from pulsars in the future would improve the constraints on Lorentz invariance violation.Comment: 2 pages, no figur

Graph Neural Networks with Generated Parameters for Relation Extraction

Recently, progress has been made towards improving relational reasoning in machine learning field. Among existing models, graph neural networks (GNNs) is one of the most effective approaches for multi-hop relational reasoning. In fact, multi-hop relational reasoning is indispensable in many natural language processing tasks such as relation extraction. In this paper, we propose to generate the parameters of graph neural networks (GP-GNNs) according to natural language sentences, which enables GNNs to process relational reasoning on unstructured text inputs. We verify GP-GNNs in relation extraction from text. Experimental results on a human-annotated dataset and two distantly supervised datasets show that our model achieves significant improvements compared to baselines. We also perform a qualitative analysis to demonstrate that our model could discover more accurate relations by multi-hop relational reasoning

Isopropylphenidate: An Ester Homolog of Methylphenidate with Sustained and Selective Dopaminergic Activity and Reduced Drug Interaction Liability

Objective: The most widely utilized pharmacological treatment of attention-deficit/hyperactivity disorder (ADHD) is the psychostimulant methylphenidate (MPH). Most MPH formulations consist of the racemic mixture of d-threo-(R, R)-MPH and l-threo-(S, S)-MPH isomers. MPH is characterized by its low bioavailability and short half-life (2?3 hours). Additionally, significant inter-individual variability in MPH pharmacokinetics has been consistently documented. Accordingly, efforts have been directed at developing alternatives to MPH as therapeutic agents. A wide range of MPH analogues (dl-α-[2-piperidyl]-phenylacetic acid esters) have been synthesized with the dopamine transporter (DAT) and norepinephrine transporter (NET) as principle neuropharmacological targets. The present study investigated the metabolic profiles and pharmacological activity of the isopropyl ester derivative of MPH, dl-isopropylphenidate (IPH), both in vitro and in vivo. Methods: The synthesis, monoaminergic transporter binding, cellular uptake profiles, and assessment of metabolic hydrolysis and transesterification in the presence of ethanol are described using MPH as a comparator. Additionally, an in vivo assessment of IPH stimulant effects (vs. saline) in rats was performed with locomotor activity as a pharmacodynamic outcome. Results: IPH displayed unique pharmacological characteristics including greater DAT than NET binding and cellular uptake activity, and greater resistance to hydrolysis and transesterification via carboxylesterase 1 relative to MPH. Further, sustained psychostimulant properties offer the prospect of an enhanced duration of action. Conclusions: Our findings are consistent with IPH exhibiting attributes distinguishing it from MPH and warranting further study and development of IPH as a novel psychotherapeutic agent.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140321/1/cap.2013.0074.pd

Effect of CCR5-Δ32 Heterozygosity on HIV-1 Susceptibility: A Meta-Analysis

So far, many studies have investigated the distribution of CCR5 genotype between HIV-1 infected patients and uninfected people. However, no definite results have been put forward about whether heterozygosity for a 32-basepair deletion in CCR5 gene (CCR5-Δ32) can affect HIV-1 susceptibility.We performed a meta-analysis of 18 studies including more than 12000 subjects for whom the CCR5-Δ32 polymorphism was genotyped. Odds ratio (OR) with 95% confidence interval (CI) were employed to assess the association of CCR5-Δ32 polymorphism with HIV-1 susceptibility.Compared with the wild-type CCR5 homozygotes, the pooled OR for CCR5-Δ32 heterozygotes was 1.02 (95%CI, 0.88–1.19) for healthy controls (HC) and 0.95 (95%CI, 0.71–1.26) for exposed uninfected (EU) controls. Similar results were found in stratified analysis by ethnicity, sample size and method of CCR5-Δ32 genotyping.The meta-analysis indicated that HIV-1 susceptibility is not significantly affected by heterozygosity for CCR5-Δ32

Black hole scalarizations induced by parity violations

It is well-known that parity symmetry is broken in the weak interaction but conserved for Einstein's general relativity and Maxwell's electromagnetic theory. Nevertheless, parity symmetry could also be violated in the gravitational/electromagnetic sectors if a fundamental scalar field couples to the parity-violating gravitational/electromagnetic curvature terms. Such parity-violating terms, which flip signs under reversed spatial directions, can inevitably lead to a negative effective mass squared for the scalar field perturbations near nonspherically symmetric black holes and thus are expected to trigger tachyonic instability. As illustrative examples, we show that the scalar field coupled to gravitational/electromagnetic Chern-Simons terms near a Kerr-Newmann spacetime can develop tachyonic instabilities, leading to equilibrium scalar field configurations in certain parameter regions of black holes. This instability, which is an indication of the black hole scalarization process, can occur in a broad class of nonspherically symmetric black holes and parity-violating theories.Comment: 9 pages, 3 figures, 1 tabl