Multiple flatbands and localized states in photonic super-Kagome lattices.

We demonstrate multiple flatbands and compact localized states (CLSs) in a photonic super-Kagome lattice (SKL) that exhibits coexistence of singular and nonsingular flatbands within its unique band structure. Specifically, we find that the upper two flatbands of an SKL are singular-characterized by singularities due to band touching with their neighboring dispersive bands at the Brillouin zone center. Conversely, the lower three degenerate flatbands are nonsingular and remain spectrally isolated from other dispersive bands. The existence of such two distinct types of flatbands is experimentally demonstrated by observing stable evolution of the CLSs with various geometrical shapes in a laser-written SKL. We also discuss the classification of the flatbands in momentum space, using band-touching singularities of the Bloch wave functions. Furthermore, we validate this classification in real space based on unit cell occupancy of the CLSs in a single SKL plaquette. These results may provide insights for the study of flatband transport, dynamics, and nontrivial topological phenomena in other relevant systems.

Direct Observation of Flatband Loop States Arising from Nontrivial Real-Space Topology.

Topological properties of lattices are typically revealed in momentum space using concepts such as the Chern number. Here, we study unconventional loop states, namely, the noncontractible loop states (NLSs) and robust boundary modes, mediated by nontrivial topology in real space. While such states play a key role in understanding fundamental physics of flatband systems, their experimental observation has been hampered because of the challenge in realizing desired boundary conditions. Using a laser-writing technique, we optically establish photonic kagome lattices with both an open boundary by properly truncating the lattice, and a periodic boundary by shaping the lattice into a Corbino geometry. We thereby demonstrate the robust boundary modes winding around the entire edge of the open lattice and, more directly, the NLSs winding in a closed loop akin to that in a torus. We prove that the NLSs due to real-space topology persist in ideal Corbino-shaped kagome lattices of arbitrary size. Our results could be of great importance for our understanding of the singular flatbands and the intriguing physics phenomenon applicable for strongly interacting systems.

High-throughput quantification of eighteen heterocyclic aromatic amines in roasted and pan-fried meat on the basis of high performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry.

Triple quadrupole mass spectrometry has been the main technique for HAAs analysis in recent decade, while it requires extensive optimization of compound-dependent parameters. A novel method based on HPLC-Q-Orbitrap-HRMS was developed firstly for simultaneous determination of eighteen HAAs. Extraction and purification conditions were optimized and the developed method was validated in terms of linearity, accuracy and precision. Results indicated eighteen HAAs and two internal standards could be separated in 12 min using a gradient elution program. The full MS/dd-MS2 scan was adopted for analysis, which indicated favorable recoveries (71.3-114.8%) along with LODs and LOQs in the ranges of 0.02-0.6 and 0.05-2.0 µg/kg, respectively. Internal standards used for calibration could effectively reduce quantification errors produced by matrix effects. The validated method was successfully applied for HAAs analysis in roasted and pan-fried meat and was confirmed to be an alternative method when triple quadrupole mass spectrometry is absent in lab.

p38 MAPK is Crucial for Wnt1- and LiCl-Induced Epithelial Mesenchymal Transition.

Idiopathic pulmonary fibrosis (IPF) is characterized by myofibroblast foci in lung parenchyma. Myofibroblasts are thought to originate from epithelial-to-mesenchymal transition (EMT). Wnt1 and lithium chloride (LiCl) induce EMT in alveolar epithelial cells (AECs), but the mechanisms are unclear. AECs were treated with Wnt1 and LiCl, respectively; morphological change and molecular changes of EMT, including E-cadherin, fibronectin, and vimentin, were observed. SB203580 was administrated to test the role of p38 МАРК signaling in EMT. Then AECs were treated with siRNAs targeting p38 МАРК to further test the effects of p38 МАРК, and the role was further confirmed by re-expression of p38 МАРК. At last P-catenin siRNA was used to test the role of ß-catenin in the EMT process and relationship of ß-catenin and p38 МАРК was concluded. Exposure of AECs to Wnt1 and LiCl resulted in upregulation of vimentin and fibronectin with subsequent downregulation of E-cadherin. Wnt1 and LiCl stimulated the p38 МАРК signaling pathways. Perturbing the p38 МАРК pathway either by SB203580 or through p38 МАРК siRNA blocked EMT and inhibited fibronetin synthesis, which were reversed by transfection of p38 МАРК expression plasmid. ß-catenin siRNA attenuated the EMT process and decreased p38 МАРК phosphorylation, indicating that ß-catenin is involved in the EMTrelated changes through regulation of p38 МАРК phosphorylation. These findings suggest that p38 МАРК participates in the pathogenesis of EMT through Wnt pathway and that p38 МАРК may be a novel target for IPF therapy.