This paper reports a technique to enhance the magnitude and high-temperature stability of Rayleigh back-scattering signals in silica fibers for distributed sensing applications. With femtosecond laser radiation, more than 40-dB enhancement of Rayleigh backscattering signal was generated in silica fibers using 300-nJ laser pulses at 250 kHz repetition rate. The laser-induced Rayleigh scattering defects were found to be stable from the room temperature to 800 °C in hydrogen gas. The Rayleigh scatter at high temperatures was correlated to the formation and modification of nanogratings in the fiber core. Using optical fibers with enhanced Rayleigh backscattering profiles as distributed temperature sensors, we demonstrated real-time monitoring of solid oxide fuel cell (SOFC) operations with 5-mm spatial resolution at 800 °C. Information gathered by these fiber sensor tools can be used to verify simulation results or operated in a process-control system to improve the operational efficiency and longevity of SOFC-based energy generation systems.

BackgroundCombination immunotherapy based on immune checkpoint inhibitors (ICIs) has shown great success in the treatment of many types of cancers and has become the mainstream in the comprehensive treatment of cancers. Ablation in combination with immunotherapy has achieved tremendous efficacy in some preclinical and clinical studies. To date, our team proved that ablation in combination with ICIs was a promising antitumor therapeutic strategy for the liver metastasis of colorectal cancer (CRC). Moreover, we found that the expression of T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) expression was up-regulated after microwave ablation (MWA), indicating that TIGIT was involved in immunosuppression, and the combination of MWA and TIGIT blockade represented a potential clinical treatment strategy.MethodsIn the present study, we examined the expression of TIGIT using a preclinical mouse model treated with MWA. Moreover, we evaluated the antitumor functions of MWA alone or in combination with TIGIT blockade by monitoring tumor growth and survival of the mice. Besides, we also detected the numbers of tumor-infiltrating lymphocytes (TILs), and effector molecules of CD8+ T cells using flow cytometry. Finally, we analyzed the single-cell RNA sequencing (scRNA-seq) data from the MWA and MWA plus anti-TIGIT groups.ResultsThe expression of TIGIT in various immune cells was up-regulated after MWA, and the addition of TIGIT blockade to MWA prolonged survival and delayed tumor growth in the MC38 tumor model. Taken together, our findings showed that TIGIT blockade in combination with MWA significantly promoted the expansion and functions of CD8+ TILs and reshaped myeloid cells in the tumor microenvironment (TME) using flow cytometry and scRNA-seq analysis.ConclusionsTIGIT blockade in combination with MWA was a novel treatment strategy for the liver metastasis of CRC, and this combination therapy could reprogram the TME toward an antitumor environment.

We present thermally regenerated fiber Bragg gratings in air-hole microstructured fibers for high-temperature, hydrostatic pressure measurements. High-temperature stable gratings were regenerated during an 800°C annealing process from hydrogen-loaded Type I seed gratings. The wavelength shifts and separation of grating peaks were studied as functions of external hydrostatic pressure from 15 to 2400 psi, and temperature from 24°C to 800°C. This Letter demonstrates a multiplexible pressure and temperature sensor technology for high-temperature environments using a single optical fiber feedthrough. © 2011 Optical Society of America OCIS codes: 060.2370, 060.4005, 120.5475, 120.6780. Sensors that operate at high temperatures are needed for a wide range of applications in the energy, automobile, and aerospace industries. For example, fast, accurate, and reliable interrogation of gas pressure information ensures safe and efficient operations of gas turbine, coal boilers, and power plants, where the operating temperatures range from 400°C to more than 1000°C. Optical fiber sensors have always been considered good candidates for harsh environment applications. A single Fabry-Perot interferometer implemented on a fiber tip can perform pressure or temperature sensing beyondCompared with fiber interferometer sensors, fiber Bragg gratings (FBGs) offer greater multiplexing capability [2], and continuous efforts have been made to improve the operating temperature of FBGs. These may involve modifying the chemical composition of the fiber core [3], and using an ultrafast laser to form a Type II damaged grating [4]. Previously, we reported a high-temperature pressure fiber sensor in which the grating was inscribed in an air-hole microstructure fiber with an ultrafast laser [5]. The Type II FBG shows stable and reproducible pressure sensing operation over 800°C. But further optimization of grating linewidth and suppression of the strong laser-induced birefringence are needed to allow better pressure sensing range and accuracy. The relatively large in-line loss with Type II permanent damage also limits sensor multiplexing.Recently, a new type of high-temperature FBG was reported, in which grating structures are regenerated after the Type I seed gratings are erased during a hightemperature annealing process [6][7][8][9][10]. Unlike chemical composition gratings, it has been shown that the regeneration process is independent from dopants in fiber cores [8] and photosensitization processes, such as hydrogen loading [10]. This versatility opens up hightemperature stabilization to other material systems and allows postregeneration of unloaded gratings, including arrays of online draw tower gratings [10]. By carefully controlling the strength of the seed grating and annealing procedures, high-temperature gratings with ∼35% reflectivity and narrow linewidth can be regenerated [7]. Stable operating temperature up to 1295°C was reported for regenerative gratings [8]. The ultrahigh temperature stability, good grating qualities, and rela...

An optical hot-wire flow sensing grid is presented using a single piece of self-heated optical fiber to perform distributed flow measurement. The flow-induced temperature loss profiles along the fiber are interrogated by the in-fiber Rayleigh backscattering, and spatially resolved in millimeter resolution using optical frequency domain reflectometry (OFDR). The flow rate, position, and flow direction are retrieved simultaneously. Both electrical and optical on-fiber heating were demonstrated to suit different flow sensing applications.

The northern microrefugia that existed during the Last Glacial Maximum (LGM) are a key factor in the demographic history of species. Pinus koraiensis has a unique distribution in northeast Asia. The Changbai Mountains and the Korean peninsula (CM/KP) are usually considered to be the LGM refugia for P. koraiensis. However, the Xiaoxingan Range (XR), at the northern part of this species’ distribution, is another possible refugium. We used chloroplast sequencing and ten nuclear single-copy gene loci to calculate the genetic diversity pattern of P. koraiensis. The probabilities of a single LGM refugium and of multiple LGM refugia were calculated based on approximate Bayesian computation. The effect of the latitudinal gradient on genetic diversity was not significant. However, unique alleles occurred at low frequencies in CM/KP and XR. A conservative estimate of the coalescence time between CM/KP and XR is 0.4 million years ago, a time prior to the LGM. Gene flow between CM/KP and XR was estimated to be more than one in per generation, an amount that may be sufficient to limit genetic divergence between the regions. Our study strongly supports the hypothesis that XR was another LGM refugium in addition to CM/KP.