Role of magnetic fields in fueling Seyfert nuclei

Molecular gas is believed to be the fuel for star formation and nuclear activity in Seyfert galaxies. To explore the role of magnetic fields in funneling molecular gas into the nuclear region, measurements of the magnetic fields embedded in molecular gas are needed. By applying the new velocity gradient technique (VGT) to ALMA and PAWS's CO isotopolog data, we obtain the first detection of CO-associated magnetic fields in several nearby Seyfert galaxies and their unprecedented high-resolution magnetic field maps. The VGT-measured magnetic fields in molecular gas globally agree with those inferred from existing HAWC+ dust polarization and VLA synchrotron polarization. An overall good alignment between the magnetic fields traced by VGT-CO and by synchrotron polarization may support the correlation between star formation and cosmic ray generation. We find that the magnetic fields traced by VGT-CO have a significant radial component in the central regions of most Seyferts in our sample, where efficient molecular gas inflows or outflows may happen. In particular, we find local misalignment between the magnetic fields traced by CO and dust polarization within the nuclear ring of NGC 1097, and the former aligns with the central bar's orientation. This misalignment reveals different magnetic field configurations in different gas phases and may provide an observational diagnostic for the ongoing multi-phase fueling of Seyfert activity.Comment: 24 pages, 14 figure

Turbulent Magnetic Field Amplification by the Interaction of Shock Wave and Inhomogeneous Medium

Magnetic fields on the order of 100 $\mu$G observed in young supernova remnants cannot be amplified by shock compression alone. To investigate the amplification caused by turbulent dynamo, we perform three-dimensional MHD simulations of the interaction between shock wave and inhomogeneous density distribution with a shallow spectrum in the preshock medium. The postshock turbulence is mainly driven by the strongest preshock density contrast and cascades to smaller scales. The resulting turbulence amplifies the postshock magnetic field. The magnetic fields' time evolution agrees with the prediction of the nonlinear dynamo theory in Xu & Lazarian (2016). When the initial weak magnetic field is perpendicular to shock normal, the total amplification of the field's strength achieves a factor of $\approx200$, which is twice larger than the one in the parallel shock case. However, the strongest magnetic field has a low volume filling factor and is limited by the turbulent energy due to the reconnection diffusion taking place in a turbulent and magnetized fluid. The magnetic field strength averaged along the shock surface is reduced by a factor $\gtrsim10$. We decompose the turbulent velocity and magnetic field into solenoidal and compressive modes. The solenoidal mode is dominant and follows the Kolmogorov scaling, even though the preshock density distribution has a shallow spectrum. When the preshock density distribution has a Kolmogorov spectrum, the fraction of the compressive component increases. We find that the perpendicular shock exhibits a smaller turbulent Alfv\'en Mach number in the vicinity of the shock front than the parallel shock.Comment: 17 pages, 15 figures, submitted to Ap

Decolourization of remazol brilliant blue R by enzymatic extract and submerged cultures of a newly isolated Pleurotus ostreatus MR3

A local white-rot fungus basidiomycete Pleurotus ostreatus MR3 was isolated from MacRitchie Reservoir Park, Singapore. Among all the ligninolytic activities, laccase was the only enzyme detected in the supernatant when the fungus was grown in liquid culture. This newly isolated white rot fungus was able to completely decolourise remazol brilliant blue R (RBBR) in-vivo on agar plates within five days and in the liquid culture (in the presence of inducers) within three days. The addition of inducers was able to enhance laccase production and therefore enhanced in-vivo RBBR decolourisation. Veratryl alcohol was shown to be the best inducer for laccase production with the maximum laccase activity reaching about 5.99 U/mL. Cu2+ also had a positive effect on laccase production, the laccase activity being enhanced to 5.24 U/mL. In-vitro RBBR decolourisation using the laccase from P. ostreatus MR3 was much comparable to that using the commercial laccase from Trameters versicolor.Keywords: Dyes, remazol brilliant blue R, Pleurotus ostreatus MR3, decolourisation, inducers, laccase activityAfrican Journal of Biotechnology Vol. 12(39), pp. 5778-578

Damping of MHD Turbulence in A Partially Ionized Medium

The coupling state between ions and neutrals in the interstellar medium plays a key role in the dynamics of magnetohydrodynamic (MHD) turbulence, but is challenging to study numerically. In this work, we investigate the damping of MHD turbulence in a partially ionized medium using 3D two-fluid (ions+neutrals) simulations generated with the AthenaK code. Specifically, we examine the velocity, density, and magnetic field statistics of the two-fluid MHD turbulence in different regimes of neutral-ion coupling. Our results demonstrate that when ions and neutrals are strongly coupled, the velocity statistics resemble those of single-fluid MHD turbulence. Both the velocity structures and kinetic energy spectra of ions and neutrals are similar, while their density structures can be significantly different. With an excess of small-scale sharp density fluctuations in ions, the density spectrum in ions is shallower than that of neutrals. When ions and neutrals are weakly coupled, the turbulence in ions is more severely damped due to the ion-neutral collisional friction than that in neutrals, resulting in a steep kinetic energy spectrum and density spectrum in ions compared to the Kolmogorov spectrum. We also find that the magnetic energy spectrum basically follows the shape of the kinetic energy spectrum of ions, irrespective of the coupling regime. In addition, we find large density fluctuations in ions and neutrals and thus spatially inhomogeneous ionization fractions. As a result, the neutral-ion decoupling and damping of MHD turbulence take place over a range of length scales.Comment: 17 pages, 14 figures, accepted for publication in MNRA

Analysis of Effect of Schisandra in the Treatment of Myocardial Infarction Based on Three-Mode Gene Ontology Network

Schisandra chinensis is a commonly used traditional Chinese medicine, which has been widely used in the treatment of acute myocardial infarction in China. However, it has been difficult to systematically clarify the major pharmacological effect of Schisandra, due to its multi-component complex mechanism. In order to solve this problem, a comprehensive network analysis method was established based-on “component–gene ontology–effect” interactions. Through the network analysis, reduction of cardiac preload and myocardial contractility was shown to be the major effect of Schisandra components, which was further experimentally validated. In addition, the expression of NCOR2 and NFAT in myocyte were experimentally confirmed to be associated with Schisandra in the treatment of AMI, which may be responsible for the preservation effect of myocardial contractility. In conclusion, the three-mode gene ontology network can be an effective network analysis workflow to evaluate the pharmacological effects of a multi-drug complex system

Cosmic ray propagation in turbulent magnetic fields

Propagation of cosmic rays (CRs) in turbulent and magnetized astrophysical media is a long-standing problem that requires both understanding of the properties of turbulent magnetic fields and their interaction with energetic particles. This review focuses on selected recent theoretical findings made based on the progress in understanding and simulating magnetohydrodynamic (MHD) turbulence. In particular, we address the problem of perpendicular and parallel propagation of CRs and identify the conditions when the perpendicular propagation is superdiffusive and diffusive. For the parallel diffusion, we discuss the problems of the traditionally used diffusion mechanism arising from pitch angle scattering and the possible solutions provided by the recently identified “mirror diffusion” in the presence of turbulent magnetic mirrors

Self-Compassion and Symptoms of Depression and Anxiety in Chinese Cancer Patients:the Mediating Role of Illness Perceptions

Objectives An adaptive role of self-compassion for psychological functioning in cancer patients has been highlighted, yet less is known about the underlying mechanisms. This study aimed to examine the mediating role of cancer patients' illness perceptions in the relations between self-compassion and psychological symptoms. Methods This cross-sectional study focused on 301 people with heterogeneous types of cancer. A self-reported questionnaire was used to collect participants' levels of self-compassion, illness perceptions, and symptoms of depression and anxiety. Parallel mediation analyses were performed to examine the research questions. Results The relation between self-compassion and depressive symptoms was mediated by perceived consequences and a timeline cyclical of cancer. Perceived consequences also mediated the relation between self-compassion and symptoms of anxiety, with an additional mediating role of personal control. Conclusions These findings suggest that both self-compassion and illness perceptions were closely linked with cancer patients' psychological symptoms. Particularly, cancer patients who feel more self-compassionate perceive fewer negative consequences of cancer, a less timeline cyclical, and more personal control over their life and report fewer psychological symptoms