Plasmonic Conducting Metal Oxide-Based Optical Fiber Sensors for Chemical and Intermediate Temperature-Sensing Applications.

The demand for real-time sensors in harsh environments at elevated temperature is significant and increasing. In this manuscript, the chemical and temperature sensing using the optical response through the practical fiber platform is demonstrated, and principle component analysis is coupled with targeted experimental film characterization to understand the fundamental sensing layer properties, which dominate measured gas sensing responses in complex gas mixtures. More specifically, tin-doped indium oxide-decorated sensors fabricated with the sol-gel method show stable and stepwise transmission responses varying over a wide range of H2 concentration (5-100%) at 250-350 °C as well as responses to CH4 and CO to a lesser extent. Measured responses are attributed to modifications to the surface plasmon resonance absorption in the near-infrared range and are dominated by the highest concentrations of the most-reducing analyte based upon systematic mixed gas stream experiments. Principal component analysis is utilized for this type of sensor to improve the quantitative and qualitative understanding of responses, clearly identifying that the dominant principle component (PC #1) accounts for ∼78% of total data variance. Correlations between PC #1 and the experimentally derived free carrier concentration confirm that this material property plays the strongest role on the ITO gas sensing mechanism, while correlations between the free carrier mobility and the second most important principle component (PC #2) suggest that this quantity may play a significant but secondary role. As such, the results presented here clarify the relationship between generalized principle components and fundamental sensing materials properties thereby suggesting the pathway toward improved multicomponent gas speciation through sensor layer engineering. The work presented represents a significant step toward the ultimate objective of optical waveguide sensors integrated with multivariate data analytics for multiparameter monitoring with a single sensor element.

Distributed Optical Fiber Sensors with Ultrafast Laser Enhanced Rayleigh Backscattering Profiles for Real-Time Monitoring of Solid Oxide Fuel Cell Operations.

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.

A hyaluronate-atelocollagen/beta-tricalcium phosphate-hydroxyapatite biphasic scaffold for the repair of osteochondral defects: a porcine study.

The authors had devised a novel biphasic scaffold combining hyaluronic acid and atelocallagen for the chondral phase and combining hydroxyapatite and beta-tricalcium phosphate for the osseous phase. Sixty-four osteochondral defects were created in the knee joints of 16 minipigs to evaluate the effectiveness of this scaffold for repairing cartilage in a large animal model. The defects were divided into five groups according to their treatment: filling with a cell/biphasic scaffold composite (Group I, 16 defects); implanting only the biphasic scaffold (Group II, 16 defects); placing the removed osteochondral fragments back into the defect (Group IIIa, 8 defects); autologous chondrocyte implantation (Group IIIb, 8 defects); leaving the defects empty (Group IV, the negative control). After 5 months, the International Cartilage Repair Society Macroscopic Score was similar in Group I (9.0), Group II (9.1), and Group IIIa (9.1), followed by Group IIIb (7.4) and Group IV (6.2). Except for three defects noted in Group IV, all the defects were filled with cartilaginous or fibrous tissue depending on the groups. The junction to the adjacent native cartilage was detectable in all the groups of minipigs. Microscopically, Group II had the highest score from the International Cartilage Repair Society Visual Histological Assessment Scale. The indentation study showed that the maximum loads and time constant of Group I, II, and IIIa defects were comparable to that of native cartilage, whereas the equilibrium loads of these groups were slightly greater than that of native cartilage. In conclusion, our results suggest that a biphasic osteochondral scaffold with a chondral phase, consisting of hyaluronate and atelocollagen, and an osseous phase, consisting of hydroxyapatite and beta-tricalcium phosphate, is effective for repairing osteochondral defects in a large animal model.

Development of a molecular marker specific to a novel CMS line in radish (Raphanus sativus L.).

In this study, we have investigated the cytoplasmic male sterility (CMS) of a novel male sterile radish line, designated NWB CMS. The NWB CMS was crossed with 16 fertile breeding lines, and all the progenies were completely male sterile. The degree of male sterility exhibited by NWB CMS is more than Ogura CMS from the Cruciferae family. The NWB CMS was found to induce 100% male sterility when crossed with all the tested breeding lines, whereas the Ogura CMS did not induce male sterility with any of the breeding lines. PCR analysis revealed that the molecular factor that influenced Ogura CMS, the orf138 gene, was absent in the NWB CMS line, and that the orf138 gene was not also expressed in this CMS line. In order to identify the cytoplasmic factors that confer male sterility in the NWB CMS line, we carried out RFLP analyses with 32 mitochondrial genes, all of which were used as probes. Fourteen genes exhibited polymorphisms between the NWB CMS line and other radish cultivars. Based on these RFLP data, intergenic primers were developed in order to amplify the intergenic regions between the polymorphic genes. Among these, a primer pair at the 3' region of the atp6 gene (5'-cgcttggactatgctatgtatga-3') and the 5' region of the nad3 gene (5'-tcatagagaaatccaatcgtcaa-3') produced a 2 kbp DNA fragment as a result of PCR. This DNA fragment was found to be specific to NWB CMS and was not present in other CMS types. It appears that this fragment could be used as a DNA marker to select NWB CMS line in a radish-breeding program.