Analytic study of superradiant stability of Kerr-Newman black holes under charged massive scalar perturbation

The superradiant stability of a Kerr-Newman black hole and charged massive scalar perturbation is investigated. We treat the black hole as a background geometry and study the equation of motion of the scalar perturbation. From the radial equation of motion, we derive the effective potential experienced by the scalar perturbation. By a careful analysis of this effective potential, it is found that when the inner and outer horizons of Kerr-Newman black hole satisfy $\frac{r_-}{r_+}\leqslant\frac{1}{3}$ and the charge-to-mass ratios of scalar perturbation and black hole satisfy $\frac{q}{\mu }\frac{Q}{ M}>1$, the Kerr-Newman black hole and scalar perturbation system is superradiantly stable.Comment: 7 pages, references adde

Floquet Weyl semimetal phases in light-irradiated higher-order topological Dirac semimetals

Floquet engineering, the concept of tailoring a system by a periodic drive, is increasingly exploited to design and manipulate topological phases of matter. In this work, we study periodically driven higher-order topological Dirac semimetals associated with a $k$-dependent quantized quadrupole moment by applying circularly polarized light. The undriven Dirac semimetals feature gapless higher-order hinge Fermi arc states which are the consequence of the higher-order topology of the Dirac nodes. Floquet Weyl semimetal phases with hybrid-order topology, characterized by both a $k$-dependent quantized quadrupole moment and a $k$-dependent Chern number, emerge when illumining circularly polarized light. Such Floquet Weyl semimetals support both hinge Fermi arc states and topological surface Fermi arc states. In addition, Floquet Weyl semimetals with tilted Weyl cones in higher-order topological Dirac semimetals are also discussed. Considering numerous higher-order topological Dirac semimetal materials were recently proposed, our findings can be testable soon.Comment: Accepted for publication as a Letter in Phys. Rev.

Theory of d+idd + id Second-Order Topological Superconductors

Topological superconductors are a class of unconventional superconducting materials featuring sub-gap zero-energy Majorana bound modes that hold promise as a building block for topological quantum computing. In this work, we study the realization of second-order topology that defines anomalous gapless boundary modes in a two-orbital superconductor with spin-orbital couplings. We reveal a time-reversal symmetry-breaking second-order topological superconducting phase with $d+id$-wave orbital-dependent paring without the need for the external magnetic field. Remarkably, this orbital-active $d$-wave paring gives rise to anomalous zero-energy Majorana corner modes, which is in contrast to conventional chiral $d$-wave pairing, accommodating one-dimensional Majorana edge modes. Our work not only reveals a unique mechanism of time-reversal symmetry breaking second-order topological superconductors but also bridges the gap between second-order topology and orbital-dependent pairings.Comment: 5+ pages, 5 figure

Effect of β-nerve growth factor on differentiation of endothelial progenitor cells in rats

Purpose: To investigate the effect of recombinant adenovirus-mediated human β-nerve growth factor (Ad-EGFP-hβ-NGF) on the differentiation of endothelial progenitor cells (EPCs) in rats.Methods: The successfully constructed Ad-EGFP-hβ-NGF and its negative control Ad-EGFP were infected into the isolated and purified rat EPCs to observe their morphological changes. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect the levels of vascular endothelial growth factor (VEGF), von Willebrand factor (vWF) and basic fibroblast growth factor (bFGF) in different rat EPC culture solutions. Western blot was performed to determine the expression of tyrosine kinase receptor A (TrKA) protein in different groups of EPCs.Results: Primary fibrous EPCs were converted into epithelium-like cells. After infection with Ad-EGFPhβ- NGF for 1 week, some EPCs became round and exhibited neural stem cell-like changes. The expression levels of VEGF, vWF and bFGF in the Ad-EGFP-hβ-NGF infection group were significantly higher than those in the control group (p < 0.01). TrKA protein in Ad-EGFP-hβ-NGF infection was also significantly up-regulated compared with that in the negative control and blank control groups (p <0.01).Conclusion: β-NGF up-regulates the expression of TrKA receptor protein and secretion of angiogenic growth factors (i.e., VEGF, vWF and bFGF), thereby promoting the differentiation of rat EPCs, which may contribute to angiopoiesis or vascular repair.Keywords: β-Nerve growth factor, Endothelial progenitor cells, Angiogenic growth factors, Tyrosine kinase receptor A, Cell differentiatio

Water-Soluble Flexible Organic Frameworks That Include and Deliver Proteins.

Four water-soluble hydrazone-based three-dimensional (3D) flexible organic frameworks FOF-1-4 have been synthesized from a semirigid tetracationic tetraaldehyde and four flexible dihydrazides. 1H NMR spectroscopy indicated the quantitative formation of FOF-1-4 in D2O, while dynamic light scattering experiments revealed that, depending on the concentration, these porous frameworks display hydrodynamic diameters ranging from 50 to 120 nm. The porosity of the frameworks is confirmed by ethanol vapor adsorption experiments of the solid samples as well as the high loading capacity for a 2.3 nm porphyrin guest in water. The new water-soluble frameworks exhibit low cytotoxicity and form inherent pores with diameters of 5.3 or 6.7 nm, allowing rapid inclusion of proteins such as bovine serum albumin and green and orange fluorescent proteins, and efficient delivery of the proteins into normal and cancer cells. Flow cytometric analysis reveals percentages of the delivered cells up to 99.8%

Effects of RNA interference-mediated gene silencing of JMJD2A on human breast cancer cell line MDA-MB-231 in vitro

Previous data demonstrate that JMJD2A is a cancer-associated gene and may be involved in human breast cancer by demethylation of H3K9me3. The aim of this study was to investigate depressive effects on JMJD2A by transfection with JMJD2A-sepcific siRNA in human breast cancer cell line MDA-MB-231 and effects on cell proliferation, invasion and migration. JMJD2A-specific siRNA was chemically synthesised and transfected into human breast cancer cell line MDA-MB-231. Expression levels of JMJD2A were detected by quantitative real-time PCR and Western blot analysis. Cells proliferation was evaluated by using flow cytometric anlysis and MTT assay. The abilities of invasion and migration were evaluated by cell migration and invasion assay with Boyden chambers. The results showed that the transfection was successful and expression levels of JMJD2A mRNA and protein in siRNA group were both down-regulated. By MTT assay, the mean actual absorbance in siRNA group was significantly lower than that in blank control group (P < 0.05) and negative control group (P < 0.05). In addition, the percentage of cells in G0/G1 phase in siRNA group was significantly more than that in blank control group (P < 0.05) and negative control group (P < 0.05). Furthermore, by cell invasion and migration assay, the decreased number of migrated cells in siRNA group was observed (P < 0.05). These data imply that silencing JMJD2A gene could result in cell cycle change and proliferation inhibition, and lead to suppress tumor cell invasion and migration. It provides a new perspective in understanding the pleiotropic functions of JMJD2A and its contribution to human breast cancer

Visualizing the elongated vortices in γ\gamma-Ga nanostrips

We study the magnetic response of superconducting $\gamma$-Ga via low temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips (width $l$ $<$ 100 nm). This is in stark contrast with the isotropic circular vortex core in a larger round-shaped Ga island. We suggest that the unusual elongated vortices in Ga nanostrips originate from geometric confinement effect probably via the strong repulsive interaction between the vortices and Meissner screening currents at the sample edge. Our finding provides novel conceptual insights into the geometrical confinement effect on magnetic vortices and forms the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio

Cognitive decline and white matter changes in mesial temporal lobe epilepsy

Noninvasive imaging plays a pivotal role in assessing the brain structural and functional changes in presurgical mesial temporal lobe epilepsy (MTLE) patients. Our goal was to study the relationship between the changes of cerebral white matter (WM) and cognitive functions in MTLE patients.Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) MRI were performed on 24 right-handed MTLE patients (12 with left MTLE and 12 with right MTLE) and 12 matching healthy controls. Gray matter (GM), WM, and whole brain (WB) volumes were measured with VBM while fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were measured with TBSS. All patients and controls also underwent Montreal Cognitive Assessment (MoCA) before MRI.WM volume and the ratio of WM volume versus WB volume were significantly lower in MTLE patients compared with controls. WM volume in MTLE patients had a positive correlation with MoCA score (r = 0.71, P < .001) and a negative correlation with the duration of epilepsy (r = -0.693, P < .001). Volumetric differences were mainly located in the corpus callosum, uncinate fasciculus, inferior longitudinal fasciculus, and superior longitudinal fasciculus. FA of both left MTLE and right MTLE groups was significantly decreased, while MD, AD, and RD were significantly increased. Most left MTLE patients showed bilateral WM fiber tract changes versus ipsilateral changes for right MTLE patients.Changes in DTI parameters and WM volume were found in MTLE patients and more ipsilateral changes were seen with right-sided MTLE. Cognitive changes of MTLE patients were found to be correlated with the changes in WM structure. These findings not only provide useful information for lateralization of the seizure focus but can also be used to explain functional connectivity disorders which may be an important physiological basis for cognitive changes in patients with MTLE

Identification and characterization of microRNAs in Clonorchis sinensis of human health significance

<p>Abstract</p> <p>Background</p> <p><it>Clonorchis sinensis </it>is a zoonotic parasite causing clonorchiasis-associated human disease such as biliary calculi, cholecystitis, liver cirrhosis, and it is currently classified as carcinogenic to humans for cholangiocarcinoma. MicroRNAs (miRNAs) are non-coding, regulating small RNA molecules which are essential for the complex life cycles of parasites and are involved in parasitic infections. To identify and characterize miRNAs expressed in adult <it>C. sinensis </it>residing chronically in the biliary tract, we developed an integrative approach combining deep sequencing and bioinformatic predictions with stem-loop real-time PCR analysis.</p> <p>Results</p> <p>Here we report the use of this approach to identify and clone 6 new and 62,512 conserved <it>C. sinensis </it>miRNAs which belonged to 284 families. There was strong bias on families, family members and sequence nucleotides in <it>C. sinensis</it>. Uracil was the dominant nucleotide, particularly at positions 1, 14 and 22, which were located approximately at the beginning, middle and end of conserved miRNAs. There was no significant "seed region" at the first and ninth positions which were commonly found in human, animals and plants. Categorization of conserved miRNAs indicated that miRNAs of <it>C. sinensis </it>were still innovated and concentrated along three branches of the phylogenetic tree leading to bilaterians, insects and coelomates. There were two miRNA strategies in <it>C. sinensis </it>for its parasitic life: keeping a large category of miRNA families of different animals and keeping stringent conserved seed regions with high active innovation in other places of miRNAs mainly in the middle and the end, which were perfect for the parasite to perform its complex life style and for host changes.</p> <p>Conclusions</p> <p>The present study represented the first large scale characterization of <it>C. sinensis </it>miRNAs, which have implications for understanding the complex biology of this zoonotic parasite, as well as miRNA studies of other related species such as <it>Opisthorchis viverrini </it>and <it>Opisthorchis felineus </it>of human and animal health significance.</p