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The WRKY transcription factor family plays important regulatory roles in multiple biological processes in higher plants. They have been identified and functionally characterized in a number of plant species, but very little is known in Neolamarckia cadamba, a 'miracle tree' for its fast growth and potential medicinal resource in Southeast Asia. In this study, a total of 85 WRKY genes were identified in the genome of N. cadamba. They were divided into three groups according to their phylogenetic features, with the support of the characteristics of gene structures and conserved motifs of protein. The NcWRKY genes were unevenly distributed on 22 chromosomes, and there were two pairs of segmentally duplicated events. In addition, a number of putative cis-elements were identified in the promoter regions, of which hormone- and stress-related elements were shared in many NcWRKYs. The transcript levels of NcWRKY were analyzed using the RNA-seq data, revealing distinct expression patterns in various tissues and at different stages of vascular development. Furthermore, 16 and 12 NcWRKY genes were confirmed to respond to various hormone treatments and two different abiotic stress treatments, respectively. Moreover, the content of cadambine, the active metabolite used for the various pharmacological activities found in N. cadamba, significantly increased after Methyl jasmonate treatment. In addition, expression of NcWRKY64/74 was obviously upregulated, suggesting that they may have a potential function of regulating the biosynthesis of cadambine in response to MeJA. Taken together, this study provides clues into the regulatory roles of the WRKY gene family in N. cadamba. [ABSTRACT FROM AUTHOR]

In this paper, a highly sensitive fiber Bragg grating (FBG) interrogation system based on a dual-loop optoelectronic oscillator (OEO) with the enhanced Vernier effect has been proposed and experimentally demonstrated. Light reflected from the FBG sensor is used as the optical source of the OEO. By introducing dispersion in the OEO loop, the sensor information encoded in the FBG wavelength can be interrogated by detecting the frequency of microwave signal generated by the OEO loop. The dispersive media in OEO has two paths, one path is formed with a roll of dispersion compensation fiber (DCF), and the other path is formed with a roll of single-mode fiber (SMF). By designing the length of two paths with slightly difference, the Vernier effect is generated in the OEO. Since the dispersion of the two paths is opposite, an enhanced Vernier effect can be realized, which can significantly enhance the sensitivity. The experimental results prove the possibility of applying the concept of enhanced Vernier effect to the OEO for temperature sensing. The sensitivity is about 0.926 kHz/°C and 0.0912 kHz/°C for a single-loop OEO with DCF and SMF, respectively. By employing the enhanced Vernier effect, the sensitivity can be improved to 141.13 kHz/°C, which is estimated about 152.4 and 1547.5 times higher than that of the two single loops, respectively. Furthermore, sensitivity can be further improved by using a dispersive link with larger dispersion. [ABSTRACT FROM AUTHOR]

Er‐activated fiber lasers are critical for many significant applications, including fiber communication, gas sensing, lidar and military. Although the design of suitable fiber materials has improved the performance of Er‐activated fiber lasers, extension of their operation wavebands still remains a significant challenge. Here, a compact all‐fiber laser is proposed and demonstrated, which can support lasing beyond 1630 nm, based on an Er‐activated hybridized glass fiber. The collaborative theoretical analysis and experimental characterization indicate that various distinct structure units can form in the hybridized fiber. This leads to the notable inhomogeneous spectral broadening. By using this hybridized fiber, a tunable fiber laser device is constructed and the wavelength can be rationally tuned in the range from 1609 to 1631 nm by mechanically stretching the fiber Bragg gratings (FBGs) manufactured by the point‐by‐point femtosecond laser inscription. Furthermore, a new fiber sensor system based on this seldom exploration waveband is built and efficient ethylene detection is demonstrated. The results highlight that rational hybridization mediated short‐ and medium‐structure modification strategy, demonstrated here in Er‐activated fiber laser, can be extended to other rare‐earth glass fiber systems for the exploration of fiber devices at new wavebands. [ABSTRACT FROM AUTHOR]

Ultrafast fiber lasers offer a unique opportunity to implement optically a Poincaré mapping in the phase space of a variety of complex dissipative dynamical systems operating far from the equilibrium. Understanding of such complex optical dynamical systems revealing, for instance, ultrafast dynamics of the dissipative solitons (DSs) and more complex regimes is important for advancing specification and performance of the mode‐locked lasers used in a vast number of applications ranging from spectroscopy and medicine to metrology and telecom. Here, using the mode‐locked fiber laser as a test‐bed, the Shilnikov‐type ultrafast dynamics taking the form of randomly switching between noise‐like pulsing and quasi‐continuous‐wave regimes is experimentally demonstrated. The transient coherence recovery is revealed, during which the noise‐like pulse (NLP) is transformed into a coherent DS state and then returned to an incoherent NLP state. The demonstrated alternation of mode synchronization and desynchronization is both of practical importance for developing new types of partially mode‐locked lasers and of the fundamental interest for the nonlinear science in the context of revealing routes to the turbulence in distributed nonlinear systems. [ABSTRACT FROM AUTHOR]

We demonstrate a proposed fiber optic sensor based on detecting the envelope of a Vernier microwave frequency comb (VMFC). A mode-locked fiber laser was employed as a microwave frequency comb source. A fiber ring, functioning as a sensor head as well as a microwave photonic filter, tailored the amplitude of each harmonic of the microwave frequency comb. By carefully designing the fiber ring length and the frequency separation of the microwave frequency comb, the Vernier effect is generated on the photodiode recovered microwave frequency comb after the laser pulses pass through the fiber ring. The sensing information can be deduced by tracking the envelope of the VMFC. The experimental results of a temperature sensing test show that the frequency shifts of the envelope peak have a good linear relationship with temperature variation. Furthermore, the sensitivity of the proposed sensor system is controllable. [ABSTRACT FROM AUTHOR]

An $8\times \,\,16$ wavelength selective switch (WSS) with full contentionless switching is proposed and experimentally demonstrated. Utilizing two chips of liquid crystal on silicon, the optical wavelengths can be switched, attenuated, or blocked among 8 input ports and 16 output ports. The maximum insertion loss is less than 14 dB; the bandwidth tuning range is from 50 to 5000 GHz. The attenuation range is from 0 to 15 dB, and the optical blocking value is greater than 27 dB. Compared with the previous reports, the $8\times16$ WSS proposed in this letter is a truly contentionless WSS device with the highest number of input and output ports. [ABSTRACT FROM AUTHOR]