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A metal-insulator-metal (MIM) waveguide consisting of two stub resonators and a ring resonator is proposed, which can be used as refractive index sensor and stop-band filter at the same time. The transmission characteristics of the MIM waveguide structure is studied by the finite element method (FEM). The simulation results show that the typical Fano profile and multiple Fano resonances can be achieved. According to the analysis, the range of stop-band and the multiple Fano resonance positions can be adjusted flexibly and independently by adjusting the aggregate parameters of the MIM waveguide structure. Moreover, it is also found that the two Fano resonances at both ends of the stop band can be determined by the two stubs, and the other two Fano resonances are regulated by the ring resonator. In addition, the spectral position of multi-Fano resonances is highly sensitive to the radius of the ring resonator and the refractive index of the filled medium. The maximum sensitivity and the figure of merit (FOM) of the MIM waveguide structure are 1650 nm/RIU and 117.8 in magnitude, respectively. These results provide a reference for implementing high-sensitivity sensors and large-bandwidth stop-band filter in MIM waveguide coupling systems based on multi-Fano resonance effect.

The scorpion venom system plays a critical role in capturing prey and defending against predators. In this study, the rapid developmental process of the first instar telson was first presented. The small amount of venom in the first instar could be stored well by the distorted and blocked venom ducts, which disappeared in the older scorpions. This special developmental process of the first instar telson revealed the notable survival ability of scorpions.

Background/Aims: KCNQ1OT1 regulates the expression of tissue-specific imprinted genes within the Kcnq1 domain. Imprinted genes are positive regulators of apoptosis, one of the forms of cell death related to cataract formation, and thus may provide novel therapeutic targets for cataract treatment. Here, we studied the role of non-coding RNAs(ncRNA) in cataract formation. Methods: Human lens epithelium cells (HLECs) were treated with H2O2, and the expression of KCNQ1OT1 and miR-214 was detected by qRT-PCR. The expression of caspase-1 was detected using qRT-PCR, western blot and immunostaining. To confirm our findings in cell cultures, we analysed KCNQ1OT1, miR-214, and caspase-1 expression in lens anterior capsules of both cataract patients and normal controls by qRT-PCR and western blot analysis. Results: We found that the expression of KCNQ1OT1 was increased in both human cataract lens anterior capsular samples and SRA01/04 cell lines treated with H2O2. Knockdown of KCNQ1OT1 expression significantly suppressed H2O2-induced SRA01/04 cell pyroptosis in vitro, which is the critical step in cataract formation. The expression of microRNA-214 (miR-214) was also decreased in cataract lens anterior capsular tissues and H2O2-induced SRA01/04 cell lines. Knockdown of KCNQ1OT1 significantly increased the expression of miR-214. Conclusions: We demonstrated for the first time that caspase-1 is a functional downstream target of miR-214, and knockdown of KCNQ1OT1 reduced the expression of caspase-1. These results provide evidence that the KCNQ1OT1-miR-214-caspase-1 regulatory network is a novel mechanism for promoting cataract formation.

A plasmon structure based on a metal-insulator-metal (MIM) waveguide composed of three stubs (TSs) is proposed, and its transmission characteristics are studied numerically by the finite element method (FEM). The simulation results show that multiple plasmon-induced transparencies (PITs) with high transmission can be produced in the structure and can be tuned effectively. By adjusting the structure parameters, more high-order PITs with narrower window are generated. Furthermore, the proposed MIM waveguide is sensitive to the environment and the maximum values of refractive index sensitivity and figure of merit (FOM) are 1340 nm R−1IU−1 and 251/RIU, respectively. Multiple, adjustable and narrow PITs with high FOM can be induced in the proposed structure, which can be used in the fields of multi-channel filters, optical switches, storages, sensors, and so on.

In this paper, a compact nanostructure is proposed that includes a metal insulator metal (MIM) waveguide with a metal wall and a side-coupled half-ring resonator. The transmission characteristics of the system are studied numerically by using the finite element method (FEM). The simulation results show that double Fano resonances can be produced in the structure, and the two Fano resonances can be controlled independently by two different half rings. The position and intensity of the Fano resonance peaks can be adjusted flexibly and easily by changing the refractive index of the filling medium. The waveguide is sensitive to the refractive index of the filling medium inside the resonator and the maximum sensitivity and figure of merit (FOM) are 1260 nm/RIU and 26,000 respectively. By adding two more half-rings below, four independently adjustable Fano resonances are obtained. The structure of this paper can be used as a sensor which can detect the glucose concentration, so it has a broad application prospect in biomedical and chemical sensing fields.

Metal-dielectric-metal (MIM) waveguide coupling systems based on surface plasmon polaritons (SPPs) are designed and studied. The finite element method is used to simulate the transmission spectra of structures in the whole simulation process. One waveguide coupling system consists of an inverted T-shaped cavity with defect (ITD) and a waveguide with a metal wall. The filter band appears in the transmission spectrum due to the opposite direction of two Fano resonances. The filter band width and the filtering range can be tuned effectively by changing the structure parameters. In this system, the center frequency and bandwidth of the filter band are 1330 nm and 114 nm, respectively. The insertion loss and reflection loss are −1.41 dB and −16.89 dB, respectively. The optimization is carried out on the basis of the first system in order to improve the filtering performance. Optimized waveguide coupling system contains an ITD and a waveguide with a slot cavity. Electromagnetically induced transparency (EIT) and Fano resonance exist simultaneously, and the filter band is induced in the transmission spectrum. In this system, the center frequency and bandwidth of the filter band are 1412 nm and 120 nm, respectively. The insertion loss and reflection loss are −0.50 dB and −37.32 dB, respectively. EIT and Fano resonance can not only be regulated independently, but also be regulated simultaneously by changing the structural parameters. And the intensity of EIT and the width of the filter band can be manipulated with changes of the structural parameters. The transmission response of SPPs propagating in the structure can be adjusted dynamically. Moreover, these novel SPPs optical waveguide structures have good filtering efficiency and can meet different filtering needs. These results show that the proposed systems are promising for filter, slow light device and photonic device integration applications.

A kind of dimer nanostructure similar to panda's eyes (P-Es), consisting two center biased elliptical rings, is proposed in this paper. The finite element method is used to study the nanostructure with the vertical incident light. The structure exhibits high order magnetic modes and the magnetic modes intensity can be manipulated independently by changing the structure parameters. The intensities of the magnetic dipole and magnetic quadrupole modes can be controlled by changing the angle between two rings and the distance of two cavity centers, respectively. Moreover, when two circular cavities increase simultaneously, the intensity of the magnetic octupole mode increases accordingly. Fano resonance can be induced when the electric mode couples with the magnetic mode. When the radius of the left circular cavity decreases, triple Fano resonance is formed. And when the whole structure is rotated, quintuple Fano resonance can be formed. More interesting, when the radii of the circular cavities of the two elliptical rings increase to 50 and 55 nm, the nanostructure becomes crescent dimer, and the enhancements of magnetic field and electric field reach 36 and 390, respectively. The P-Es structure has potential application value in multiwavelength surface enhanced spectroscopy and biochemical sensing.

A human corneal stroma induced pluripotent stem cell (HMUi001-A) line was created from primary cultured human corneal fibroblasts. Reprogramming was performed using episomal vector delivery of OCT4, SOX2, KLF4, L-MYC and LIN28. Further characterization of the HMUi001-A confirmed that the cell line was pluripotent, free from Epstein Barr viral genome, and retained normal karyotype.

The Optical properties of the Square Split Ring dimer (SSRD) nanostructure is studied by the finite element method (FEM). Fano resonance can be excited in the visible and near-infrared bands by changing geometrical parameters of the SSRD or the arrangement of two square split rings (SSR). The production mechanism of Fano resonance is illustrated by using the plasmon hybridization theory (PHT). At the meantime, a pair of reverse current circulation is formed in the SSRD nanostructures and the maximum magnetic field enhancement reaches 45.69. In addition, calculation results show that the maximum refractive index sensitivities and the figure of merit (FOM) of SSRD systems reached 2043 nm/RIU and 57.9, respectively. Based on these features of the SSRD system, it may have potential application in sensor devices and surface-enhanced Raman scattering (SERS).

In recent years, various nanostructures related to Fano resonance have been proposed by many researchers due to their outstanding optical properties. A structure consisting of two double-split rings (TD-SR) is researched by using finite element method in this paper. When the incident light is normal to the structure surface, a magnetic Fano resonance can be generated by the interference of bright electric mode and dark magnetic mode. In addition, when the symmetry of the structure is destroyed along x-axis or y-axis, double Fano resonances will be generated. At the same time, the maximum refractive index sensitivity (S) and the maximum figure of merit at resonance mode can reach 1200 nm/RIU and 30.61, respectively. More interestingly, the electromagnetically induced transparency (EIT)-like behavior can be induced when the cavity of inner split ring is biased and the corresponding electric and magnetic field enhancements can reach 229 and 52, respectively. The optical properties of our nanostructure make it has important application value in the fields of multi-wavelength sensor, ultra-sensitive biosensor, surface enhanced spectroscopy and slow light.

An understanding of the mechanism of cataract formation may reduce its burden on medical care worldwide. It is established that pyroptosis is associated with oxidative stress, one of the causes of cataracts, and may provide novel therapeutic targets for the treatment of cataracts. The present study therefore investigated the role of pyroptosis in cataract formation. SRA01/04 human lens epithelium cells (HLECs) were treated with H2O2 and cell viability was assessed by an MTT assay. Pyroptosis in HLECs was examined by TUNEL staining, and the expression of caspase‑1 and interleukin (IL)‑1β was determined using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), western blot analysis and immunostaining. A caspase‑1 inhibitor was used to investigate the effects of caspase‑1 downregulation. In addition, the expression of caspase‑1 and IL‑1β in lens anterior capsule tissue samples from patients with cataracts and normal controls was also analyzed by immunostaining, RT‑qPCR and western blot analysis. The results demonstrated that pyroptosis in H2O2‑treated HLECs, and the mRNA and protein expression of caspase‑1 and IL‑1β, was significantly increased compared with control cells. Furthermore, caspase‑1 and IL‑1β expression was significantly increased in cataract tissue samples compared with normal controls. When HLECs were cotreated with a caspase‑1 inhibitor and 100 µM H2O2, caspase‑1 and IL‑1β expression were decreased compared with the 100 µM H2O2‑only group. In conclusion, the results of the present study demonstrate that pyroptosis may have a role in cataract formation, and the caspase‑1 and IL‑1β pathways may be involved in this pathological process. Pyroptosis appears to be a promising target in the prevention of cataract formation.