3,654 research outputs found
Luttinger-volume violating Fermi liquid in the pseudogap phase of the cuprate superconductors
Based on the NMR measurements on BiSrLaCuO
(La-Bi2201) in strong magnetic fields, we identify the non-superconducting
pseudogap phase in the cuprates as a Luttinger-volume violating Fermi liquid
(LvvFL). This state is a zero temperature quantum liquid that does not break
translational symmetry, and yet, the Fermi surface encloses a volume smaller
than the large one given by the Luttinger theorem. The particle number enclosed
by the small Fermi surface in the LvvFL equals the doping level , not the
total electron number . Both the phase string theory and the dopon
theory are introduced to describe the LvvFL. For the dopon theory, we can
obtain a semi-quantitative agreement with the NMR experiments.Comment: The final version in PR
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Tet3 regulates synaptic transmission and homeostatic plasticity via DNA oxidation and repair.
Contrary to the long-held belief that DNA methylation of terminally differentiated cells is permanent and essentially immutable, post-mitotic neurons exhibit extensive DNA demethylation. The cellular function of active DNA demethylation in neurons, however, remains largely unknown. Tet family proteins oxidize 5-methylcytosine to initiate active DNA demethylation through the base-excision repair (BER) pathway. We found that synaptic activity bi-directionally regulates neuronal Tet3 expression. Functionally, knockdown of Tet or inhibition of BER in hippocampal neurons elevated excitatory glutamatergic synaptic transmission, whereas overexpressing Tet3 or Tet1 catalytic domain decreased it. Furthermore, dysregulation of Tet3 signaling prevented homeostatic synaptic plasticity. Mechanistically, Tet3 dictated neuronal surface GluR1 levels. RNA-seq analyses further revealed a pivotal role of Tet3 in regulating gene expression in response to global synaptic activity changes. Thus, Tet3 serves as a synaptic activity sensor to epigenetically regulate fundamental properties and meta-plasticity of neurons via active DNA demethylation
Paeoniflorin inhibits the growth of bladder carcinoma via deactivation of STAT3
Bladder cancer (BCa) is one of the most common urinary cancers. The present study aims to investigate whether Paeoniflorin (Pae) can exert inhibitory effects on BCa. The results showed that Pae inhibited proliferation of human BCa cell lines in a concentration- and time-dependent manner. Pae and cisplatin (Cis) synergistically inhibited the growth of tumours in RT4-bearing mice. Pae treatment neutralized the body loss induced by Cis. Moreover, Pae induced apoptosis in RT4 cells and increased the activities of caspase3, caspase8 and caspase9. Western blotting and immunohistochemical analysis revealed that the phosphorylated signal transducer and activator of transcription-3 (p-STAT3) level were decreased in Pae-treated RT4 cells and Pae-treated tumour-bearing mice. Furthermore, STAT3 transcriptional target B-cell lymphoma-2 was decreased in Pae-treated RT4 cells. Interestingly, Pae prevented translocation of STAT3 to the nucleus in RT4 cells. Collectively, Pae inhibits the growth of BCa, at least in part, via a STAT3 pathway
Tunable magnetism and electron correlation in Titanium-based Kagome metals RETi3Bi4 (RE = Yb, Pr, and Nd) by rare-earth engineering
Rare-earth engineering is an effective way to introduce and tune the
magnetism in topological Kagome magnets, which has been acting as a fertile
platform to investigate the quantum interactions between geometry, topology,
spin, and correlation. Here we report the structure and properties of three
newly discovered Titanium-based Kagome metals RETi3Bi4 (RE = Yb, Pr, and Nd)
with various magnetic states. They crystalize in the orthogonal space group
Fmmm (No.69), where slightly distorted Ti Kagome lattice, RE triangular
lattice, Bi honeycomb and triangular lattices stack along the a axis. By
changing the rare earth atoms on RE zag-zig chains, the magnetism can be tuned
from nonmagnetic YbTi3Bi4 to short-range ordered PrTi3Bi4 (Tanomaly ~ 8.2 K),
and finally to ferromagnetic NdTi3Bi4 (Tc ~ 8.5 K). The measurements of
resistivity and specific heat capacity demonstrate an evolution of electron
correlation and density of states near the Fermi level with different rare
earth atoms. In-situ resistance measurements of NdTi3Bi4 under high pressure
further reveal a potential relationship between the electron correlation and
ferromagnetic ordering temperature. These results highlight RETi3Bi4 as another
family of topological Kagome magnets to explore nontrivial band topology and
exotic phases in Kagome materials.Comment: Manuscript:17 pages, 5 figures; Supporting information:11 pages, 11
tables and 10 figure
Acceleration of on-axis and ring-shaped electron beams in wakefields driven by Laguerre-Gaussian pulses
The acceleration of electron beams with multiple transverse structures in wakefields driven by Laguerre-Gaussian pulses has been studied through three-dimensional (3D) particle-in-cell simulations. Under different laser-plasma conditions, the wakefield shows different transverse structures. In general cases, the wakefield shows a donut-like structure and it accelerates the ring-shaped hollow electron beam. When a lower plasma density or a smaller laser spot size is used, besides the donut-like wakefield, a central bell-like wakefield can also be excited. The wake sets in the center of the donut-like wake. In this case, both a central on-axis electron beam and a ring-shaped electron beam are simultaneously accelerated. Further, reducing the plasma density or laser spot size leads to an on-axis electron beam acceleration only. The research is beneficial for some potential applications requiring special pulse beam structures, such as positron acceleration and collimation
The Viral TRAF Protein (ORF111L) from Infectious Spleen and Kidney Necrosis Virus Interacts with TRADD and Induces Caspase 8-mediated Apoptosis
Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the Megalocytivirus genus of the Iridoviridae family. It causes a serious and potentially pandemic disease in wild and cultured fishes. ISKNV infection induces evident apoptosis in mandarin fish (Siniperca chuatsi) and zebrafish (Danio renio). However, the mechanism is still unknown. After a genome-wide bioinformatics analysis of ISKNV-encoded proteins, the ISKNV open reading frame 111L (ORF111L) shows a high similarity to the tumour necrosis factor receptor-associated factor (TRAF) encoded by fish, mice and mammals, which is essential for apoptotic signal transduction. Moreover, ORF111L was verified to directly interact with the zebrafish TNF receptor type 1 associated death domain protein (TRADD). A recombinant plasmid containing the DNA sequence of ORF111L was constructed and microinjected into zebrafish embryos at the 1β2 cell stage to investigate its biological function in vivo. ORF111L overexpression in the embryos resulted in increased apoptosis. ORF111L-induced apoptosis was clearly associated with significant caspase 8 upregulation and activation. The knockdown of zebrafish caspase 8 expression effectively blocked the apoptosis induced by ORF111L overexpression. Significantly, ORF111L overexpression resulted in much stronger effect on caspase 8 and caspase 3 upregulation compared to zebrafish TRAF2. This is the first report of a viral protein similar to TRAF that interacts with TRADD and induces caspase 8-mediated apoptosis, which may provide novel insights into the pathogenesis of ISKNV infection
Acceleration and evolution of a hollow electron beam in wakefields driven by a Laguerre-Gaussian laser pulse
We show that a ring-shaped hollow electron beam can be injected and accelerated by using a Laguerre-Gaussian laser pulse and ionization-induced injection in a laser wakefield accelerator. The acceleration and evolution of such a hollow, relativistic electron beam are investigated through three-dimensional particle-in-cell simulations. We find that both the ring size and the beam thickness oscillate during the acceleration. The beam azimuthal shape is angularly dependent and evolves during the acceleration. The beam ellipticity changes resulting from the electron angular momenta obtained from the drive laser pulse and the focusing forces from the wakefield. The dependence of beam ring radius on the laser-plasma parameters (e.g., laser intensity, focal size, and plasma density) is studied. Such a hollow electron beam may have potential applications for accelerating and collimating positively charged particles
Flexible strain sensor enabled by carbon nanotubes-decorated electrospun TPU membrane for human motion monitoring
High-performance flexible strain sensors are gaining more and more attention with their bespoken detection range, excellent sensing performance and good stability, which are highly desired in the wearable electronics. Herein, a thermoplastic polyurethane elastomer (TPU) fibrous membrane was prepared as a flexible substrate by electrostatic spinning technology, then a coating of polydopamine was formed through fast synthesizing the dopamine on TPU fibrous membrane surface and loaded with CNTs to develop an extremely sensitive flexible strain sensor. The flexible sensor prepared by TPU fibrous membrane coated with polydopamine layer has an outstanding sensibility under the pulling force (GF of 10528.53 with 200 strain), rapid reaction time (188-221 ms), wide sensing range (up to 200), good stability and durability. The theoretical studies reveals that the underlying cause for the high sensitivity and the inherit relationship between the amount of conducting routes and the length between adjacent conducting fillers in the sensor. The demonstration of device shows a promising application to sense the human motion at various locations of body, with accurate and stable electrical signal output generated at corresponding motion
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