Realization and Topological Properties of Third-Order Exceptional Lines Embedded in Exceptional Surfaces

As the counterpart of Hermitian nodal structures, the geometry formed by exceptional points (EPs), such as exceptional lines (ELs), entails intriguing spectral topology. We report the experimental realization of order-3 exceptional lines (EL3) that are entirely embedded in order-2 exceptional surfaces (ES2) in a three-dimensional periodic synthetic momentum space. The EL3 and the concomitant ES2, together with the topology of the underlying space, prohibit the evaluation of their topology in the eigenvalue manifold by prevailing topological characterization methods. We resolve this issue by defining a winding number that associates with the resultants of the Hamiltonian. This resultant winding number detects EL3 but ignores the ES2, allowing the diagnosis of the topological currents carried by the EL3, which enables the prediction of their evolution under perturbations. Our results exemplify unprecedented topology of higher-order exceptional geometries and may inspire new non-Hermitian topological applications.Comment: 14 pages, 4 figure

Distinct Axonemal Processes Underlie Spontaneous and Stimulated Airway Ciliary Activity

Cilia are small organelles protruding from the cell surface that beat synchronously, producing biological transport. Despite intense research for over a century, the mechanisms underlying ciliary beating are still not well understood. Even the nature of the cytosolic molecules required for spontaneous and stimulated beating is debatable. In an effort to resolve fundamental questions related to cilia beating, we developed a method that integrates the whole-cell mode of the patch-clamp technique with ciliary beat frequency measurements on a single cell. This method enables to control the composition of the intracellular solution while the cilia remain intact, thus providing a unique tool to simultaneously investigate the biochemical and physiological mechanism of ciliary beating. Thus far, we investigated whether the spontaneous and stimulated states of cilia beating are controlled by the same intracellular molecular mechanisms. It was found that: (a) MgATP was sufficient to support spontaneous beating. (b) Ca2+ alone or Ca2+-calmodulin at concentrations as high as 1 μM could not alter ciliary beating. (c) In the absence of Ca2+, cyclic nucleotides produced a moderate rise in ciliary beating while in the presence of Ca2+ robust enhancement was observed. These results suggest that the axonemal machinery can function in at least two different modes

On Interval-Valued Hesitant Fuzzy Soft Sets

By combining the interval-valued hesitant fuzzy set and soft set models, the purpose of this paper is to introduce the concept of interval-valued hesitant fuzzy soft sets. Further, some operations on the interval-valued hesitant fuzzy soft sets are investigated, such as complement, “AND,” “OR,” ring sum, and ring product operations. Then, by means of reduct interval-valued fuzzy soft sets and level hesitant fuzzy soft sets, we present an adjustable approach to interval-valued hesitant fuzzy soft sets based on decision making and some numerical examples are provided to illustrate the developed approach. Finally, the weighted interval-valued hesitant fuzzy soft set is also introduced and its application in decision making problem is shown

Experimental Realization of Weyl Exceptional Rings in a Synthetic Three-Dimensional Non-Hermitian Phononic Crystal

Weyl points (WPs) are isolated degeneracies carrying quantized topological charges, and are therefore robust against Hermitian perturbations. WPs are predicted to spread to the Weyl exceptional rings (WERs) in the presence of non-Hermiticity. Here, we use a one-dimensional (1D) Aubry-Andre-Harper (AAH) model to construct a Weyl semimetal in a 3D parameter space comprised of one reciprocal dimension and two synthetic dimensions. The inclusion of non-Hermiticity in the form of gain and loss produces a WER. The topology of the WER is characterized by both its topological charge and non-Hermitian winding numbers. The WER is experimentally observed in a 1D phononic crystal with the non-Hermiticity introduced by active acoustic components. In addition, Fermi arcs are observed to survive the presence of non-Hermitian effect. We envision our findings to pave the way for studying the high-dimensional non-Hermitian topological physics in acoustics.Comment: 14 pages, 5 figure

Application of a novel strong promoter from Chinese fir (Cunninghamia lanceolate) in the CRISPR/Cas mediated genome editing of its protoplasts and transgenesis of rice and poplar

Novel constitutive promoters are essential for plant biotechnology. Although in angiosperms, a number of promoters were applied in monocots or dicots genetic engineering, only a few promoters were used in gymnosperm. Here we identified two strong promoters (Cula11 and Cula08) from Chinese fir (C. lanceolate) by screening the transcriptomic data and preliminary promoter activity assays in tobacco. By using the newly established Chinese fir protoplast transient expression technology that enables in vivo molecular biology studies in its homologous system, we compared the activities of Cula11 and Cula08 with that of the commonly used promoters in genetic engineering of monocots or dicots, such as CaM35S, CmYLCV, and ZmUbi, and our results revealed that Cula11 and Cula08 promoters have stronger activities in Chinese fir protoplasts. Furthermore, the vector containing Cas gene driven by Cula11 promoter and sgRNA driven by the newly isolated CulaU6b polyIII promoters were introduced into Chinese fir protoplasts, and CRISPR/Cas mediated gene knock-out event was successfully achieved. More importantly, compared with the commonly used promoters in the genetic engineering in angiosperms, Cula11 promoter has much stronger activity than CaM35S promoter in transgenic poplar, and ZmUbi promoter in transgenic rice, respectively, indicating its potential application in poplar and rice genetic engineering. Overall, the novel putative constitutive gene promoters reported here will have great potential application in gymnosperm and angiosperm biotechnology, and the transient gene expression system established here will serve as a useful tool for the molecular and genetic analyses of Chinese fir genes

Evaluation of the antitumor effects of c-Myc-Max heterodimerization inhibitor 100258-F4 in ovarian cancer cells

Abstract Epithelial ovarian carcinoma is the most lethal gynecological cancer due to its silent onset and recurrence with resistance to chemotherapy. Overexpression of oncogene c-Myc is one of the most frequently encountered events present in ovarian carcinoma. Disrupting the function of c-Myc and its downstream target genes is a promising strategy for cancer therapy. Our objective was to evaluate the potential effects of small-molecule c-Myc inhibitor, 10058-F4, on ovarian carcinoma cells and the underlying mechanisms by which 10058-F4 exerts its actions. Using MTT assay, colony formation, flow cytometry and Annexin V FITC assays, we found that 10058-F4 significantly inhibited cell proliferation of both SKOV3 and Hey ovarian cancer cells in a dose dependent manner through induction of apoptosis and cell cycle G1 arrest. Treatment with 10058-F4 reduced cellular ATP production and ROS levels in SKOV3 and Hey cells. Consistently, primary cultures of ovarian cancer treated with 10058-F4 showed induction of caspase-3 activity and inhibition of cell proliferation in 15 of 18 cases. The response to 10058-F4 was independent the level of c-Myc protein over-expression in primary cultures of ovarian carcinoma. These novel findings suggest that the growth of ovarian cancer cells is dependent upon c-MYC activity and that targeting c-Myc-Max heterodimerization could be a potential therapeutic strategy for ovarian cancer