Cobalt ion-assisted enhancement of photochemical vapor generation in a mixed acid medium was used for sensitive determination of tellurium(iv) by atomic fluorescence spectrometry.

A live, attenuated respiratory syncytial virus and parainfluenza virus type 3 vaccine was evaluated in healthy respiratory syncytial virus/parainfluenza virus type 3 seropositive children aged 1 to 9 years. Three cohorts of 40 children were randomized 1:1 to receive 10, 10, or 10 median tissue culture infectious dose50 MEDI-534 vaccine or placebo. The vaccine's safety profile was similar to placebo, no viral shedding was detected, and the vaccine was minimally immunogenic.

Objective: To characterize the structure and to evaluate the cytotoxicity of cellulose nanowhiskers (CNW) prepared from cotton linters.Methods: A series of CNW dispersions was prepared by hydrolyzing cotton linters with sulfuric acid. The structure of CNW was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The cytotoxicity of CNW dispersions to L929 cells was preliminarily investigated by cell culture and MTT assay.Results: SEM and TEM observation showed that the original cotton litters have been successfully acid-hydrolyzed into cellulose nanowhiskers having needle-or short rod-like structure with an average length of 250 nm and diameter of 10 nm. XRD patterns suggested that degree of crystalline in the CNW was much higher than that in the cotton linters as a result that the acid-hydrolysis process has removed the amorphous domains in the cotton linters. The results from MTT assay and cell morphology observation indicated that CNW with concentration from 0.01% to 0.2% had low toxicity to L929 cells, while cytotoxicity showed an increase tendency with an increase in the concentration of CNW.Conclusions: Cellulose nanowhiskers dispersion could be prepared from cotton linters by acid-hydrolysis process. CNW showed potential applications as nanobiomaterials due to its low cytotoxicity.