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We present baria-silica erbium-doped fibers (BaEDF) for extending the bandwidth of L-band EDFAs beyond 1620 nm. Using a combination of modified chemical vapor deposition (MCVD) process and solution-doping technique, we demonstrate low loss (<10 dB/km at 1200 nm) fiber cores with BaO concentration of 1-3 mol% and Er3+ concentration of 8×1024 m-3 . We show that the optical properties and EDFA performance are positively affected by increasing the BaO content. Namely, when we increase the BaO concentration from 1.3 to 3 mol%, we observe a reduction of pair-induced quenching that correlates with a biexponential luminescence decay with a dominant 15.5 ms lifetime component. Furthermore, the slight modifications of absorption/ emission coefficients point to a red-shift of the signal excited state absorption and consequently, to a moderate extension of the L-band gain to longer wavelengths (1622 nm).

Rayleigh scattering enhanced nanoparticle-doped optical fibers is a technology very promising for distributed sensing applications, however, it remains largely unexplored. This work demonstrates for the first time the possibility of tuning Rayleigh scattering and optical losses in Ca-based nanoparticle-doped silica optical fibers by controlling the kinetics of the re-nucleation process that nanoparticles undergo during fiber drawing by controlling preform feed, drawing speed and temperature. A 3D study by SEM, FIB-SEM and optical backscatter reflectometry (OBR) reveals an early-time kinetics at 1870 °C, with tunable Rayleigh scattering enhancement 43.2–47.4 dB, regarding a long-haul single mode fiber, SMF-28, and associated sensing lengths of 3–5.5 m. At 2065 °C, kinetics is slower and nanoparticle dissolution is favored. Consequently, enhanced scattering values of 24.9–26.9 dB/m and sensing lengths of 135–250 m are attained. Finally, thermal stability above 500 °C and tunable distributed temperature sensitivity are proved, from 18.6 pm/°C to 23.9 pm/°C, ∼1.9–2.4 times larger than in a SMF-28. These results show the promising future of Rayleigh scattering enhanced nanoparticle-doped optical fibers for distributed sensing.

Rayleigh scattering enhanced nanoparticle-doped optical fibers is a technology very promising for distributed sensing applications, however, it remains largely unexplored. This work demonstrates for the first time the possibility of tuning Rayleigh scattering and optical losses in Ca-based nanoparticle-doped silica optical fibers by controlling the kinetics of the re-nucleation process that nanoparticles undergo during fiber drawing by controlling preform feed, drawing speed and temperature. A 3D study by SEM, FIB-SEM and optical backscatter reflectometry (OBR) reveals an early-time kinetics at 1870 °C, with tunable Rayleigh scattering enhancement 43.2–47.4 dB, regarding a long-haul single mode fiber, SMF-28, and associated sensing lengths of 3–5.5 m. At 2065 °C, kinetics is slower and nanoparticle dissolution is favored. Consequently, enhanced scattering values of 24.9–26.9 dB/m and sensing lengths of 135–250 m are attained. Finally, thermal stability above 500 °C and tunable distributed temperature sensitivity are proved, from 18.6 pm/°C to 23.9 pm/°C, ∼1.9–2.4 times larger than in a SMF-28. These results show the promising future of Rayleigh scattering enhanced nanoparticle-doped optical fibers for distributed sensing.

Rayleigh scattering enhanced nanoparticles-doped optical fibers are highly promising for distributed sensing applications, however, the high optical losses induced by that scattering enhancement restrict considerably their sensing distance to few meters. Fabrication of long-range distributed optical fiber sensors based on this technology remains a major challenge in optical fiber community. In this work, it is reported the fabrication of low-loss Ca-based nanoparticles doped silica fibers with tunable Rayleigh scattering for long-range distributed sensing. This is enabled by tailoring nanoparticle features such as particle distribution size, morphology and density in the core of optical fibers through preform and fiber fabrication process. Consequently, fibers with tunable enhanced backscattering in the range 25.9-44.9 dB, with respect to a SMF-28 fiber, are attained along with the lowest two-way optical losses, 0.1-8.7 dB/m, reported so far for Rayleigh scattering enhanced nanoparticles-doped optical fibers. Therefore, the suitability of Ca-based nanoparticles-doped optical fibers for distributed sensing over longer distances, from 5 m to more than 200 m, becomes possible. This study opens a new path for future works in the field of distributed sensing, since these findings may be applied to other nanoparticles-doped optical fibers, allowing the tailoring of nanoparticle properties, which broadens future potential applications of this technology.

The metal sites of MIL-100(Fe), MIL-100(Fe,Al), and MIL-100(Al) metal–organic frameworks (MOFs) were decorated with ethylenediamine (EN). Interestingly, the Al-containing MOFs presented hierarchized porosity, and their structural integrity was maintained upon functionalization. Solution and solid-state NMR confirmed the grafting efficiency in the case of MIL-100(Al) and the presence of a free amine group. It was shown that MIL-100(Al) can be functionalized by only one EN molecule in each trimeric Al3O cluster unit, whereas the other two aluminum sites are occupied by a hydroxyl and a water molecule. The −NH2 sites of the grafted ethylenediamine can be used for further postfunctionalization through amine chemistry and are responsible for the basicity of the functionalized material as well as increased affinity for CO2. Furthermore, the presence of coordinated water molecules on the Al-MOF is responsible for simultaneous Brønsted acidity. Finally, the Al-containing MOFs show an unusual carbon dioxide sorption mechanism at high pressures that distinguishes those materials from their iron and chromium counterparts and is suspected to be due to the presence of polarized Al–OH bonds.

Rayleigh scattering enhanced nanoparticles-doped optical fibers are highly promising for distributed sensing applications, however, the high optical losses induced by that scattering enhancement restrict considerably their sensing distance to few meters. Fabrication of long-range distributed optical fiber sensors based on this technology remains a major challenge in optical fiber community. In this work, it is reported the fabrication of low-loss Ca-based nanoparticles doped silica fibers with tunable Rayleigh scattering for long-range distributed sensing. This is enabled by tailoring nanoparticle features such as particle distribution size, morphology and density in the core of optical fibers through preform and fiber fabrication process. Consequently, fibers with tunable enhanced backscattering in the range 25.9-44.9 dB, with respect to a SMF-28 fiber, are attained along with the lowest two-way optical losses, 0.1-8.7 dB/m, reported so far for Rayleigh scattering enhanced nanoparticles-doped optical fibers. Therefore, the suitability of Ca-based nanoparticles-doped optical fibers for distributed sensing over longer distances, from 5 m to more than 200 m, becomes possible. This study opens a new path for future works in the field of distributed sensing, since these findings may be applied to other nanoparticles-doped optical fibers, allowing the tailoring of nanoparticle properties, which broadens future potential applications of this technology.

Thiamphenicol (TAP) is reported to be effective against many respiratory pathogens including methicillin-resistant Staphylococcus aureus (MRSA). However, its poor solubility in water remains as one of the obstacles hindering the preparation of inhalable TAP formulations. The aim of this study was to improve the dissolution rate of TAP by micronization, and investigate whether variations in the dissolution rates of TAP would affect its in vitro antibacterial activity. Inhalable dry powders composed of TAP microcrystals (MDP) or nanocrystals (NDP) were prepared by using a wet ball milling method followed by spray drying. The morphology, solid state and in vitro dissolution of these dry powders were characterized. In vitro antibacterial activities of the inhalable TAP dry powders against a MRSA strain were evaluated. A dissolution-efficacy model relating antibacterial activity with time and dissolution rate was established via modified time-kill assays. Upon being spray dried, the volumetric mean diameters of MDP and NDP were found to be around 5 µm. Solid state analyses showed that MDP and NDP possess the same crystalline form as the raw materials. NDP exhibited faster in vitro dissolution rate as compared to MDP. The in vitro antibacterial efficiency of NDP and MDP were superior to raw TAP when the test was performed at a TAP concentration of 32 mg/L. Simulated colony forming units predictions were consistent with the result measured in the time-kill experiments with Raw TAP, MDP and NDP. This study characterized the effect of the dissolution rate of TAP dry powders on in vitro antibacterial activity against MRSA, and an enhanced antibacterial activity of TAP was observed with an increase in the dissolution rate of TAP from the dry powders at certain concentration ranges.

Space-division multiplexing (SDM), whereby multiple spatial channels in multimode1 and multicore2 optical fibres are used to increase the total transmission capacity per fibre, is being investigated to avert a data capacity crunch3,4 and reduce the cost per transmitted bit. With the number of channels employed in SDM transmission experiments continuing to rise, there is a requirement for integrated SDM components that are scalable. Here, we demonstrate a cladding-pumped SDM erbium-doped fibre amplifier (EDFA) that consists of six uncoupled multimode erbium-doped cores. Each core supports three spatial modes, which enables the EDFA to amplify a total of 18 spatial channels (six cores × three modes) simultaneously with a single pump diode and a complexity similar to a single-mode EDFA. The amplifier delivers >20 dBm total output power per core and <7 dB noise figure over the C-band. This cladding-pumped EDFA enables combined space-division and wavelength-division multiplexed transmission over multiple multimode fibre spans.

Space-division multiplexing (SDM), whereby multiple spatial channels in multimode1 and multicore2 optical fibres are used to increase the total transmission capacity per fibre, is being investigated to avert a data capacity crunch3,4 and reduce the cost per transmitted bit. With the number of channels employed in SDM transmission experiments continuing to rise, there is a requirement for integrated SDM components that are scalable. Here, we demonstrate a cladding-pumped SDM erbium-doped fibre amplifier (EDFA) that consists of six uncoupled multimode erbium-doped cores. Each core supports three spatial modes, which enables the EDFA to amplify a total of 18 spatial channels (six cores × three modes) simultaneously with a single pump diode and a complexity similar to a single-mode EDFA. The amplifier delivers >20 dBm total output power per core and <7 dB noise figure over the C-band. This cladding-pumped EDFA enables combined space-division and wavelength-division multiplexed transmission over multiple multimode fibre spans.

Colistin is a polymyxin antibiotic which is used to treat patients infected with multidrug resistant Gram negative bacteria (MDR-GNB). The objective of this work was to develop a whole-body physiologically based pharmacokinetic (WBPBPK) model in rat for colistin and its prodrug, CMS. The Kp prior values of colisin and CMS used in the WBPBPK model were either measured ex vivo in rat tissue homogenates or calculated using an in silico model. The PK parameters were estimated fitting plasma concentrations from rats receiving an i.v. bolus of CMS. In the WBPBPK model, the tissue distribution was assumed to be well-stirred and perfusion-limited. Three scenarios were investigated: estimating the Kp values using in silico Kp prior values (I), estimating the Kp values using the Kp prior values from ex vivo experiments (II) and fixing the Kp values to the experimental ex vivo Kp values (III). The WBPBPK model well described CMS and colistin plasma concentration-time profiles. Colistin Kp values in kidneys were higher than in the other tissues. The predicted concentrations in tissue were highest for kidneys and brain which might be due to a high affinity for these tissues and/or active transport processes that remain poorly elucidated. The clearance estimates of CMS and colistin were in agreement with previously reported values in the literature. The model developed in this study might be a valuable tool in drug development to understand the disposition of colistin or new polymyxin candidates as well as to guide for optimal dosing regimens.