Carbon nanotube mode lockers with enhanced nonlinearity via evanescent field interaction in D-shaped fibers

We demonstrate a novel passive mode-locking scheme for pulsed lasers enhanced by the interaction of carbon nanotubes (CNTs) with the evanescent field of propagating light in a D-shaped optical fiber. The scheme features all-fiber operation as well as a long lateral interaction length, which guarantees a strong nonlinear effect from the nanotubes. Mode locking is achieved with less than 30% of the CNTs compared with the amount of nanotubes used for conventional schemes. Our method also ensures the preservation of the original morphology of the individual CNTs. The demonstrated pulsed laser with our CNT mode locker has a repetition rate of 5.88 MHz and a temporal pulse width of 470 fs.     

Time-resolved resonance Raman study of the reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide

A time-resolved resonance Raman investigation of the reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide in a mixed aqueous solvent is presented. The reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide in the mixed aqueous solution generates two new species on the microsecond time scale. One of these species is identified as 2,2'-azobisfluorene, and the other species is tentatively assigned to a 1,4-bis-(2,2'-fluorenyl)-tetrazadiene cation intermediate. The structure and properties of these two species are briefly discussed. The reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide is also briefly compared to that of the 2-fluorenylnitrenium ion reactions with guanosine and water.     

Dual-reductant synthesis of nickel nanoparticles for use in screen-printing conductive paste

Journal of Nanoparticle Research - A Correction to this paper has been published: https://doi.org/10.1007/s11051-020-05065-5     

Mixed Food Waste as Renewable Feedstock in Succinic Acid Fermentation

Mixed food waste, which was directly collected from restaurants without pretreatments, was used as a valuable feedstock in succinic acid (SA) fermentation in the present study. Commercial enzymes and crude enzymes produced from Aspergillus awamori and Aspergillus oryzae were separately used in hydrolysis of food waste, and their resultant hydrolysates were evaluated. For hydrolysis using the fungal mixture comprising A. awamori and A. oryzae, a nutrient-complete food waste hydrolysate was generated, which contained 31.9 g L^?1 glucose and 280 mg L^?1 free amino nitrogen. Approximately 80–90 % of the solid food waste was also diminished. In a 2.5 L fermentor, 29.9 g L^?1 SA was produced with an overall yield of 0.224 g g^?1 substrate using food waste hydrolysate and recombinant Escherichia coli. This is comparable to many similar studies using various wastes or by-products as substrates. Results of this study demonstrated the enormous potential of food waste as renewable resource in the production of bio-based chemicals and materials via microbial bioconversion.     

Free porphyrin catalyzed direct C-H arylation of benzene with aryl halides

A general procedure for free porphyrin catalyzed direct C-H arylation of benzene was demonstrated. This air tolerant, transition-metal-free process provides a promising system for cheap and efficient synthesis of biaryls in a user-friendly approach.     

Determination of peptide content and purity of DOTA-peptides by metal ion titration and UPLC: an alternative method to monitor quality of DOTA-peptides

PRRT requires high specific activities, thus at low molar ratio between DOTA-peptide and radioactivity. Therefore, the ingredients of the reaction, including (radio)metals and DOTA-peptide must be pure and the content known. Our aim was to quantify content and purity of DOTA-peptide by a base-to-base separation of DOTA-peptide and metal-DOTA-peptide by UPLC and UV-detection. Quantification of these peaks reveals an accurate and sensitive method to quantify purity and content of DOTA-peptides. Moreover, this technique enables monitoring of the (radio)labeling process and co-introduction of impurities, including metal ions.     

Development of an electrochemical membrane-based nanobiosensor for ultrasensitive detection of dengue virus

A sensitive membrane-based electrochemical nanobiosensor is developed for the detection of dengue type 2 virus (DENV-2) using nanoporous alumina-modified platinum electrode. Its sensing mechanism relies on the monitoring of electrode's Faradaic current response toward redox probe, ferrocenemethanol, which is sensitive toward the formation of immune complexes within the alumina nanochannels. Anti-DENV-2 monoclonal antibody (clone 3H5, isotype IgG) is used as the biorecognition element in this work. The stepwise additions of antibody, bovine serum albumin (BSA) and DENV-2 are characterized by differential pulse voltammetry (DPV). A low detection limit of 1 pfu mL⁻¹ with linear range from 1 to 10³ pfu mL⁻¹ (R² = 0.98) can be achieved by the nanobiosensor. The nanobiosensor is selective toward DENV-2 with insignificant cross reaction with non-specific viruses, Chikungunya virus, West Nile virus and dengue type 3 virus (DENV-3). Relative standard deviation (RSD) for triplicate analysis of 5.9% indicates an acceptable level of reproducibility. The first direct quantitation of DENV-2 concentration in whole mosquito vector is demonstrated using this electrochemical nanobiosensor.