Cancer-associated fibroblasts promote enzalutamide resistance and PD-L1 expression in prostate cancer through CCL5-CCR5 paracrine axis.

Cancer-associated fibroblasts (CAFs) have been shown to play a key role in prostate cancer treatment resistance, but the role of CAFs in the initial course of enzalutamide therapy for prostate cancer remains unclear. Our research revealed that CAFs secrete CCL5, which promotes the upregulation of androgen receptor (AR) expression in prostate cancer cells, leading to resistance to enzalutamide therapy. Furthermore, CCL5 also enhances the expression of tumor programmed death-ligand 1 (PD-L1), resulting in immune escape. Mechanistically, CCL5 binds to the receptor CCR5 on prostate cancer cells and activates the AKT signaling pathway, leading to the upregulation of AR and PD-L1. The CCR5 antagonist maraviroc to inhibit the CAFs mediated CCL5 signaling pathway can effectively reduce the expression of AR and PD-L1, and improve the efficacy of enzalutamide. This study highlights a promising therapeutic approach targeting the CCL5-CCR5 signaling pathway to improve the effectiveness of enzalutamide.

Direct observation of topological magnon polarons in a multiferroic material.

Magnon polarons are novel elementary excitations possessing hybrid magnonic and phononic signatures, and are responsible for many exotic spintronic and magnonic phenomena. Despite long-term sustained experimental efforts in chasing for magnon polarons, direct spectroscopic evidence of their existence is hardly observed. Here, we report the direct observation of magnon polarons using neutron spectroscopy on a multiferroic Fe2Mo3O8 possessing strong magnon-phonon coupling. Specifically, below the magnetic ordering temperature, a gap opens at the nominal intersection of the original magnon and phonon bands, leading to two separated magnon-polaron bands. Each of the bands undergoes mixing, interconverting and reversing between its magnonic and phononic components. We attribute the formation of magnon polarons to the strong magnon-phonon coupling induced by Dzyaloshinskii-Moriya interaction. Intriguingly, we find that the band-inverted magnon polarons are topologically nontrivial. These results uncover exotic elementary excitations arising from the magnon-phonon coupling, and offer a new route to topological states by considering hybridizations between different types of fundamental excitations.

Superconductivity and density-wave fluctuations in an extended triangular Hubbard model: an application to SnSe2.

We employ the fluctuation-exchange approximation to study the relation of superconducting pairing symmetries and density-wave fluctuations based on the extended triangular Hubbard model upon electron doping and interactions, with an possible application to the layered metal dichalcogenide SnSe2. For the case where the interactions between electrons contain only the on-site Hubbard term, the superconducting pairings are mainly mediated by spin fluctuations, and the spin-singlet pairing with thed-wave symmetry robustly dominates in the low and moderate doping levels, and ad-wave to extendeds-wave transition is observed as the electron doping reachesn = 1. When the near-neighbor site Coulomb interactions are also included, the charge fluctuations are enhanced, and the spin-triplet pairings with thep-wave andf-wave symmetries can be realized in the high and low doping levels, respectively.

Quantum interference and domain-wall-like magnetic correlations in hexagonal graphene nanodisks.

Quantum interference and traditional domain wall effects are two common ways to manipulate the magnetism in magnetic materials. Here, we report both effects emerge in the designed graphene nanodisks simultaneously, and thus providing an accessible way to engineer the magnetism in graphene nanostructures. By adjusting the length of the armchair edges at the corners of hexagonal disk, connecting the adjacent zigzag edges, we show that the quantum interference among the zigzag edges remains robust and consequently determines the magnetic structure in the small-size systems, in analogy with the nanoribbons. More importantly, a domain-wall-like magnetic mechanism is numerically identified to dominate the larger-size disks. In particular, a magnetic state with fully spin-polarized edges achieved in a wide parameter region promises the future applications for spintronics.

Erratum: Realization of a Metallic State in 1T-TaS_{2} with Persisting Long-Range Order of a Charge Density Wave [Phys. Rev. Lett. 123, 206405 (2019)].

This corrects the article DOI: 10.1103/PhysRevLett.123.206405.

Realization of a Metallic State in 1T-TaS_{2} with Persisting Long-Range Order of a Charge Density Wave.

Metallization of 1T-TaS_{2} is generally initiated at the domain boundary of a charge density wave (CDW), at the expense of its long-range order. However, we demonstrate in this study that the metallization of 1T-TaS_{2} can be also realized without breaking the long-range CDW order upon surface alkali doping. By using scanning tunneling microscopy, we find the long-range CDW order is always persisting, and the metallization is instead associated with additional in-gap excitations. Interestingly, the in-gap excitation is near the top of the lower Hubbard band, in contrast to a conventional electron-doped Mott insulator where it is beneath the upper Hubbard band. In combination with the numerical calculations, we suggest that the appearance of the in-gap excitations near the lower Hubbard band is mainly due to the effectively reduced on-site Coulomb energy by the adsorbed alkali ions.

Quasiparticle Properties under Interactions in Weyl and Nodal Line Semimetals.

The quasiparticle spectra of interacting Weyl and nodal-line semimetals on a cubic lattice are studied using the cluster perturbation theory. By tracking the spectral functions under interaction, we find that the Weyl points will move to and meet at a specific point in one Weyl semimetal model, while in the other Weyl semimetal model they are immobile. In the nodal-line semimetals, we find that the nodal line shrinks to a point and then disappears under interaction in one-nodal-line system. When we add another nodal line to this system, we find that the two nodal lines both shrink to specific points, but the disappearing processes of the two nodal lines are not synchronized. We argue that the nontrivial evolution of Weyl points and nodal lines under interaction is due to the presence of symmetry breaking order, e.g., a ferromagnetic moment, in the framework of mean field theory, whereas the stability of Weyl points under interaction is protected by symmetry. Among all these models, the spectral gap is finally opened when the interaction is strong enough.

[Clinical characterization of testicular yolk sac tumor in children and adults].

OBJECTIVE: To compare the clinical characteristics of simple testicular yolk sac tumor (YST) in children with those in adults so as to improve the diagnosis and treatment of the malignance. METHODS: This study included 75 cases of simple testicular YST pathologically confirmed between May 2008 and July 2018, which were divided into groups A (aged <18 years, n = 64) and B (aged ≥18 years, n = 11). We analyzed the clinical data on all the cases and compared the clinical manifestations, laboratory results, pathological findings, clinical stages, treatment methods and prognostic outcomes between the two groups of patients. RESULTS: The patients of group A ranged in age from 6 months to 5 years (ï¼»1.38 ± 0.89ï¼½ yr), with the tumor diameter of 0.9－6.0 (2.48 ± 1.12) cm, while those of group B from 25 to 49 years (median 34 years), with the tumor diameter of 3.5－6.3 (5.16 ± 1.32) cm, most presenting with a painless scrotal mass, 4 (6.2%) in group A and 5 (45.5%) in group B with testis pain. There were statistically significant differences between the two groups in the tumor diameter and initial manifestations (P < 0.05). All the patients were treated by radical high-level spermatectomy and orchiectomy and, in addition, 1 in group A and 3 in group B by retroperitoneal lymph node dissection (RPLND), 24 in the former and 5 in the latter group followed by chemotherapy. Elevated levels of serum alpha-fetoprotein (AFP) were observed in all the cases. Sixty-five of the patients were followed up for 10－78 (52.00 ± 23.78) months, during which 2 cases of simple metastasis, 3 cases of simple relapse, 3 cases of relapse with metastasis and 5 cases of death were found in group A, and 5 cases of simple metastasis, 1 case of simple relapse, 1 case of relapse with metastasis and 4 cases of death in group B. CONCLUSIONS: There are significant differences in the clinical manifestation, biological behavior, treatment and prognosis of testicular YST between children and adults. In children, most of the testicular YST cases are at clinical stage I and preferably treated by radical high-level spermatectomy and orchiectomy with favorable prognosis. In adults, however, the tumor is highly malignant, with high incidences of recurrence and metastasis and poor prognosis, for the treatment of which the first choice is radical high-level spermatectomy and orchiectomy combined with RPLND and chemotherapy.

Dynamics of a single hole in the Heisenberg-Kitaev model: a self-consistent Born approximation study.

The magnetic properties of 4d and 5d transition-metal insulating compounds with the honeycomb structure are believed to be described by the Heisenberg-Kitaev model, which contains both the isotropic Heisenberg interaction J and anisotropic Kitaev interaction K. In this paper, we study the single-hole propagation of the t-J-K model in various magnetically ordered phases by the self-consistent Born approximation. We find that there are low-energy coherent quasiparticle (QP) excitations in all of these phases which appear firstly around the K point in the first Brillouin zone (BZ), but the bandwidths of these QPs are very small due to the hole-magnon coupling. Interestingly, in the zigzag phase relevant to recent experiments, though the QP weights are largely suppressed in the physical spectra in the first BZ, we find that they recover in the extended BZs. Moreover, our results reveal that the low-energy QP spectra are reduced with the increase of K.

Discovery of coexisting Dirac and triply degenerate magnons in a three-dimensional antiferromagnet.

Topological magnons are emergent quantum spin excitations featured by magnon bands crossing linearly at the points dubbed nodes, analogous to fermions in topological electronic systems. Experimental realisation of topological magnons in three dimensions has not been reported so far. Here, by measuring spin excitations (magnons) of a three-dimensional antiferromagnet Cu3TeO6 with inelastic neutron scattering, we provide direct spectroscopic evidence for the coexistence of symmetry-protected Dirac and triply degenerate nodes, the latter involving three-component magnons beyond the Dirac-Weyl framework. Our theoretical calculations show that the observed topological magnon band structure can be well described by the linear-spin-wave theory based on a Hamiltonian dominated by the nearest-neighbour exchange interaction J1. As such, we showcase Cu3TeO6 as an example system where Dirac and triply degenerate magnonic nodal excitations coexist, demonstrate an exotic topological state of matter, and provide a fresh ground to explore the topological properties in quantum materials.

Spin-Glass Ground State in a Triangular-Lattice Compound YbZnGaO_{4}.

We report on comprehensive results identifying the ground state of a triangular-lattice structured YbZnGaO_{4} as a spin glass, including no long-range magnetic order, prominent broad excitation continua, and the absence of magnetic thermal conductivity. More crucially, from the ultralow-temperature ac susceptibility measurements, we unambiguously observe frequency-dependent peaks around 0.1 K, indicating the spin-glass ground state. We suggest this conclusion holds also for its sister compound YbMgGaO_{4}, which is confirmed by the observation of spin freezing at low temperatures. We consider disorder and frustration to be the main driving force for the spin-glass phase.

Width-Tuned Magnetic Order Oscillation on Zigzag Edges of Honeycomb Nanoribbons.

Quantum confinement and interference often generate exotic properties in nanostructures. One recent highlight is the experimental indication of a magnetic phase transition in zigzag-edged graphene nanoribbons at the critical ribbon width of about 7 nm [ Magda , G. Z. et al. Nature 2014 , 514 , 608 ]. Here we show theoretically that with further increase in the ribbon width, the magnetic correlation of the two edges can exhibit an intriguing oscillatory behavior between antiferromagnetic and ferromagnetic, driven by acquiring the positive coherence between the two edges to lower the free energy. The oscillation effect is readily tunable in applied magnetic fields. These novel properties suggest new experimental manifestation of the edge magnetic orders in graphene nanoribbons and enhance the hopes of graphene-like spintronic nanodevices functioning at room temperature.

Spin-Wave Excitations Evidencing the Kitaev Interaction in Single Crystalline α-RuCl_{3}.

Kitaev interactions underlying a quantum spin liquid have long been sought, but experimental data from which their strengths can be determined directly, are still lacking. Here, by carrying out inelastic neutron scattering measurements on high-quality single crystals of α-RuCl_{3}, we observe spin-wave spectra with a gap of ∼2 meV around the M point of the two-dimensional Brillouin zone. We derive an effective-spin model in the strong-coupling limit based on energy bands obtained from first-principles calculations, and find that the anisotropic Kitaev interaction K term and the isotropic antiferromagnetic off-diagonal exchange interaction Γ term are significantly larger than the Heisenberg exchange coupling J term. Our experimental data can be well fit using an effective-spin model with K=-6.8 meV and Γ=9.5 meV. These results demonstrate explicitly that Kitaev physics is realized in real materials.

Consistent picture of the octet-nodal gap and its evolution with doping in heavily overdoped Ba(1-x)KxFe2As2.

We investigate the pairing symmetry in heavily overdoped Ba(1-x)KxFe2As2 based on the spin-fluctuation mechanism. We propose a Fermi-patch mechanism that is different from the conventional Fermi-surface-nesting picture. The exotic octet nodes of the superconducting gap and the unusual evolution of the gap with doping observed by the recent experiments are well explained in a unified manner. We demonstrate that the scattering of electrons on the Fermi patches is mainly responsible for the incommensurate spin fluctuations and consequently the Fermi-surface-dependent multi-gap structure, since the Fermi level is close to the flat band. In addition, we find that a d-wave pairing state will prevail over the s-wave pairing state around the Lifshitz transition point.

Spin fluctuations and pairing symmetry in AxFe2-ySe2: dual effect of the itinerant and the localized nature of electrons.

We investigate the spin fluctuations and the pairing symmetry in AxFe2-ySe2 by the fluctuation exchange approximation. Besides the on-site interactions, the next-nearest-neighbor antiferromagnetic coupling J2 is also included. We find that both the itinerant and the localized natures of electrons are important to describe recent experimental results on the spin fluctuations and the pairing symmetry. In particular, a small J2 coupling can change the pairing gap from the d-wave symmetry to the extended s-wave symmetry. We have also studied the real-space structures of the gap functions for different orbits in order to gain more insight into the nature of the pairing mechanism.

Mott physics and topological phase transition in correlated dirac fermions.

We investigate the interplay between the strong correlation and the spin-orbit coupling in the Kane-Mele-Hubbard model and obtain the qualitative phase diagram via the variational cluster approach. We identify, through an increase of the Hubbard U, the transition from the topological band insulator to either the spin liquid phase or the easy-plane antiferromagnetic insulating phase, depending on the strength of the spin-orbit coupling. A nontrivial evolution of the bulk bands in the topological quantum phase transition is also demonstrated.

Spin-fluctuation-mediated pairing symmetry on the metallic kagome lattice.

We study the magnetic properties and the superconducting pairing mediated by spin fluctuations on the metallic kagome lattice by using the Hubbard model and the fluctuation exchange approximation. It is found that the spin susceptibility is caused by the nesting of the renormalized Fermi surface. We point out that superconductivity will be favored in the spin-singlet channel and may be more easily realized around 25% hole doping. We find an evolution of the pairing state from a d-wave-like symmetry, described by the E(2g) representation of the group D(6h) at low dopings, to that described by the A(2g) representation at heavy hole dopings.

[Seed geography: its concept and basic scientific issues].

In this paper, a new concept 'seed geography' was provided, and its definition, research contents, and scientific issues were put forward. Seed geography is a newly developed interdisciplinary science from plant geography, seed ecology, and phytosociology, which studies the geographic variation patterns of seed biological traits as well as their relationships with environmental factors from macroscopic to microscopic, and the seed formation, development, and change trends. The main research contents would include geography of seed mass, geography of seed chemical components, geography of seed morphology, geography of seed cell biological characteristics, geography of seed physiological characteristics, geography of seed genetic characteristics, and geography of flower and fruit. To explore the scientific issues in seed geography would help us to better understand the long-term adaptation and evolution of seed characteristics to natural environments.

[Research on evaluation methods of road ecological effects: a case study of Lan-Hai highway].

The ecological effects of roads are systematically and quantitatively evaluated using different methods and metrics in three scales. The small scale effects are assessed by in-situ measurement, the middle scale effects by remote sensing monitoring in different resolution and large scale effects by spatial models based on RS and GIS. The results are satisfactory when this system was applied to Lan-Hai highway. The system can be an important reference to highway ecological effects assessment.