Nanomaterials are used in practically every aspect of modern life, including agriculture. The aim of this study was to evaluate the effectiveness of iron oxide nanoparticles (Fe2O3 NPs) as a fertilizer to replace traditional Fe fertilizers, which have various shortcomings. The effects of the Fe2O3 NPs and a chelated-Fe fertilizer (ethylenediaminetetraacetic acid-Fe; EDTA-Fe) fertilizer on the growth and development of peanut (Arachis hypogaea), a crop that is very sensitive to Fe deficiency, were studied in a pot experiment. The results showed that Fe2O3 NPs increased root length, plant height, biomass, and SPAD values of peanut plants. The Fe2O3 NPs promoted the growth of peanut by regulating phytohormone contents and antioxidant enzyme activity. The Fe contents in peanut plants with Fe2O3 NPs and EDTA-Fe treatments were higher than the control group. We used energy dispersive X-ray spectroscopy (EDS) to quantitatively analyze Fe in the soil. Peanut is usually cultivated in sandy soil, which is readily leached of fertilizers. However, the Fe2O3 NPs adsorbed onto sandy soil and improved the availability of Fe to the plants. Together, these results show that Fe2O3 NPs can replace traditional Fe fertilizers in the cultivation of peanut plants. To the best of our knowledge, this is the first research on the Fe2O3 NPs as the iron fertilizer.

A series of Eu(2+) and Eu(2+)/Tb(3+) activated novel Ba3LaNa(PO4)3F phosphors have been synthesized by traditional solid state reaction. Rietveld structure refinement of the obtained phosphor indicates that the Ba3LaNa(PO4)3F host contains three kinds of Ba sites. The photoluminescence properties exhibit that the obtained phosphors can be efficiently excited in the range from 320 to 430 nm, which matches perfectly with the commercial n-UV LED chips. The critical distance of the Eu(2+) ions in Ba3LaNa(PO4)3F:Eu(2+) is calculated and the energy quenching mechanism is proven to be dipole-dipole interaction. Tunable blue-green emitting Ba3LaNa(PO4)3F:Eu(2+),Tb(3+) phosphor has been obtained by co-doping Eu(2+) and Tb(3+) ions into the host and varying their relative ratios. Compared with the Tb(3+) singly doped phosphor, the codoped phosphors have more intense absorption in the n-UV range and stronger emission of the Tb(3+) ions, which are attributed to the effective energy transfer from the Eu(2+) to Tb(3+) ions. The energy transfer from the Eu(2+) to Tb(3+) ions is demonstrated to be a dipole-quadrupole mechanism by the Inokuti-Hirayama (I-H) model. The Eu(2+) and Tb(3+) activated phosphor may be good candidates for blue-green components in n-UV white LEDs.

No abstract

We designed and synthesized a novel oligo(thiophene ethynylene) (OTE) to investigate the antibacterial activities against Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Ralstonia solanacearum and Escherichia coli) bacteria in vitro by photodynamic therapy (PDT). Notably, OTE presents broad-spectrum and greatly high antibacterial activities after white light irradiation at nanogram per milliliter concentrations. The half inhibitory concentrations (IC50) values obtained for S. aureus, S. epidermidis, E. coli, and R. solanacearum are 8, 13, 24, and 52 ng/mL after illumination for 30 min, respectively, which are lower than that of other PDT agents. Interestingly, OTE shows the specific and very strong dark killing capability against S. aureus at the concentration of 180 ng/mL for 30 min, which is the highest efficiency biocide against S. aureus without the need of irradiation to date. The antibacterial mechanism investigated demonstrated that reactive oxygen species or singlet-oxygen generated by OTE kills bacteria irreversibly upon white light irradiation, and OTE as a v-type oligomer exerts its toxicity directly on destroying bacterial cytoplasmic membrane in the dark. Importantly, the OTE shows no cell cytotoxicity and excellent biocompatibility. The results indicate that it is potential to provide versatile applications in the efficient control of pathogenic organisms and specific application for killing S. aureus.

In this paper, the color point tuning of Y 3 Al 5 O 12 : Ce 3+ phosphor has been realized by the incorporation of Mn 2+ -Si 4+ . The Mn 2+ ions occupy the dodecahedral crystallographic Y 3+ site, while the Si 4+ ions substitute the tetrahedral Al 3+ crystallographic site in the obtained powder. Under 450 nm excitation, the YAG : Ce 3+ ,Mn 2+ ,Si 4+ samples exhibit the typical yellowish-green emission band of the Ce 3+ ions, as well as an orange emission band of the Mn 2+ ions. Furthermore, the intensity ratio of the orange/yellowish-green band can be enhanced through the increase of Mn 2+ -Si 4+ content. The intense orange emission band of the Mn 2+ ions is attributed to the effective energy transfer from the Ce 3+ to Mn 2+ ions, which has been justified through the luminescence spectra and the fluorescence decay dynamics. The related mechanism was demonstrated to be the electric dipole-quadrupole interaction based on the Inokuti-Hirayama theoretical model, and critical distance is calculated to be 8.6A by the spectral overlap method.

Here, a two-step method has been developed for synthesizing carboxy-terminated NaYF(4): Yb(3+), Er(3+)@SiO(2) core@shell nanoparticles (UCNP@SiO(2)) with ultrathin shell (1.5 nm). First, the NaYF(4): Yb(3+), Er(3+) upconverting nanoparticles (UCNPs) were prepared using solvothermal technology; then, silica shells (SiO(2)) were deposited on the nanocrystals to form core-shell structures by the hydrolysis of tetraethylorthosilicate (TEOS). The ultrathin SiO(2) shell was obtained by increasing surfactant amount and decreasing TEOS amount in the reaction mixture. Carboxyethylsilanetriol (CTES) was used to generate the carboxy group on the particle surface. The carboxy-terminated UCNP@SiO(2) are ideally suited for biolabeling and bioimaging applications because the as-prepared nanoparticles have extreme colloidal and optical stabilities, and the carboxy groups on the particle surface easily react with amino residues of biomolecules. As an example, we reported on the interactions of Ricinus Communis Agglutinin (RCA 120) conjugated UCNP@SiO(2) with HeLa cells. The excellent performance of the RCA 120 conjugated UCNP@SiO(2) in cellular fluorescence imaging was demonstrated.

The metathesis of ethene and 2-butene to propene was studied over WO 3 /SiO 2 catalysts with various WO 3 loadings (2, 4, 8, 12, 16, and 24 wt%). The 2-butene conversion and propene selectivity increased greatly with WO 3 loading increasing from 2 to 8 wt%, reached maximum at 8-12 wt% WO 3 loading, and then decreased when the WO 3 loading was higher than 12 wt%. From the above results and taking the economics into account, the optimal amount of WO 3 loading was *8 wt%. The catalysts were characterized by physico-chemical and spectroscopic techniques to elucidate the effect of different tungsten oxide loadings on the metathesis reactivity of ethene and 2-butene. The characterization data indicated that three types of tungsten species (i.e., surface tetrahedral tungsten species, surface octahedral polytungstate species, and WO 3 crystallites) were present in the catalysts. It was found that WO 3 was not the active centers, and surface tetrahedral tungsten species might be more active than octahedral polytungstate species in metathesis reaction. The reduced form of tungsten species [W ?4 , W ?5 , and W ?(6-y) (0 \ y \ 1)] may be the suitable state of W species acting as metathesis active centers.

The Eu(2+) → Tb(3+) → Sm(3+) energy transfer scheme has been proposed to realize the sensitization of Sm(3+) ion emission by Eu(2+) ions. Following this energy transfer model, near-UV convertible Sm(3+)-activated orange phosphors have been obtained in Sr3Y(PO4)3:Eu(2+), Tb(3+), Sm(3+) powders.