Evaluation of hydroxyl radical pathway and kinetic process for bubbling ozonation of methylene blue as reference compound

<p>Ozonation experiments were conducted in a bubble column reactor taking methylene blue (MB) as model compound, where the role of solution pH and organic load as basic parameters of wastewater influencing pathway of hydroxyl radical () and the kinetics were investigated. The relative significance of -pathway was evaluated compared to molecular ozone in both kinetics and degradation process. Results showed that, as solution pH increased from 5 to 11, the contribution of (labeled as <i>θ</i>) got intensified from 0.05 up to 0.80 (apparent abundance proliferated up to 35.76 × 10⁻⁷ M), giving rise to an exponential growth of pseudo-first-order rate constant as well as an enhanced mineralization. Reduction of initial organic concentration ([C]_0,MB) retarded chemical gas-to-liquid absorption of ozone and the global degradation of MB, while interestingly at the same time, the kinetic rate constant on MB decolorization accordingly began to grow up since the -pathway impact substantially got reinforced (<i>θ</i> elevated from 0.80 up to 1.944 when [C]_0,MB decreased from 80 to 20 mg L⁻¹ under pH 11).</p

Mean fitness weightings for each social structure pattern in the random initial condition (N = 300 populations).

<p>Mean fitness weightings for each social structure pattern in the random initial condition (N = 300 populations).</p

Mean fitness weightings for each social structure pattern in the first experiment with an initial equal distribution of agent strategies.

<p>Mean fitness weightings for each social structure pattern in the first experiment with an initial equal distribution of agent strategies.</p

Average weights of fitness criteria for clusters producing the layered pattern found in humans.

<p>Average weights of fitness criteria for clusters producing the layered pattern found in humans.</p

Mean number of agents in each layer in the four different final social patterns identified by cluster analysis.

<p>Mean number of agents in each layer in the four different final social patterns identified by cluster analysis.</p

Mean number of agents in each layer for the five different final social patterns identified by cluster analysis in the random initial condition.

<p>Mean number of agents in each layer for the five different final social patterns identified by cluster analysis in the random initial condition.</p

A SAR-based mechanistic study on the combined toxicities of sulfonamides and quorum sensing inhibitors on <i>Escherichia coli</i>

<p>Quorum sensing inhibitors (QSIs) are promising alternatives to antibiotics, but they are discharged into the environment after their use cycle. This poses joint effects on the organisms in the environment. Therefore, it is of great importance to study the combined toxicities of QSIs and antibiotics. In this study, we investigated the single and combined toxicities of four potential QSIs and 11 sulfonamides (SAs) on <i>Escherichia coli.</i> The results revealed that the single toxicities of SAs were greater than those of QSIs, and the toxicities were found positively related to the binding energies (<i>E</i>_bind) with their target proteins, for both antibiotics and QSIs. The combined toxicities of the binary mixtures were observed to be either antagonism or addition. The antagonism could be explained by the phenomenon that QSIs changed SAs molecules into ionic forms, preventing the SA molecules entering the bacteria. Furthermore, it was found that the ratios of the effective concentration (the actual concentration involved in the interaction with the proteins) in the antagonistic cases were higher than those in the additive cases. This study would benefit both rational use of the drug combination and ecological risk assessment of antibiotics and QSIs in the real environment.</p

Micromechanics and Poroelasticity of Hydrated Cellulose Networks

The micromechanics of cellulose hydrogels have been investigated using a new rheological experimental approach, combined with simulation using a poroelastic constitutive model. A series of mechanical compression steps at different strain rates were performed as a function of cellulose hydrogel thickness, combined with small amplitude oscillatory shear after each step to monitor the viscoelasticity of the sample. During compression, bacterial cellulose hydrogels behaved as anisotropic materials with near zero Poisson’s ratio. The micromechanics of the hydrogels altered with each compression as water was squeezed out of the structure, and microstructural changes were strain rate-dependent, with increased densification of the cellulose network and increased cellulose fiber aggregation observed for slower compressive strain rates. A transversely isotropic poroelastic model was used to explain the observed micromechanical behavior, showing that the mechanical properties of cellulose networks in aqueous environments are mainly controlled by the rate of water movement within the structure

Litsea Species as Potential Antiviral Plant Sources

Litsea verticillata Hance (Lauraceae), a Chinese medicine used to treat swelling caused by injury or by snake bites, was the first plant identified by our National Institutes of Health (NIH)-funded International Cooperative Biodiversity Group (ICBG) project to exhibit anti-HIV activities. From this plant, we discovered a class of 8 novel litseane compounds, prototypic sesquite rpenes, all of which demonstrated anti-HIV activities. In subsequent studies, 26 additional compounds of different structural types were identified. During our continuing investigation of this plant species, we identified two new litseanes, litseaverticillols L and M, and a new sesquiterpene butenolide, litseasesquibutenolide. Litseaverticillols L and M were found to inhibit HIV-1 replication, with an IC50 value of 49.6μM. To further determine the antiviral properties of this plant, several relatively abundant isolates, including a litseane compound, two eudesmane sesquiterpenes and three lignans, were evaluated against an additional 21 viral targets. Lignans 8 and 9 were shown to be active against the Epstein-Barr Virus (EBV), with EC50 values of 22.0μM (SI=3.8) and 16.2μM (SI>6.2), respectively. Since many antiviral compounds have been discovered in L. verticillata, we further prepared 38 plant extracts made from the different plant parts of 9 additional Litsea species. These extracts were evaluated for their anti-HIV and cytotoxic activities, and four of the extracts, which ranged across three different species, displayed 97-100% inhibitory effects against HIV replication without showing cytotoxicity to a panel of human cell lines at a concentration of 20μg/mL

Atomic Structure and Structural Stability of Sc₇₅Fe₂₅ Nanoglasses

Nanoglasses are solids consisting of nanometer-sized glassy regions connected by interfaces having a reduced density. We studied the structure of Sc₇₅Fe₂₅ nanoglasses by electron microscopy, positron annihilation spectroscopy, and small-/wide-angle X-ray scattering. The positron annihilation spectroscopy measurements showed that the as-prepared nanoglasses consisted of 65 vol% glassy and 35 vol% interfacial regions. By applying temperature annealing to the nanoglasses and measuring in situ small-angle X-ray scattering, we observed that the width of the interfacial regions increased exponentially as a function of the annealing temperature. A quantitative fit to the small-angle X-ray scattering data using a Debye–Bueche random phase model gave a correlation length that is related to the sizes of the interfacial regions in the nanoglass. The correlation length was found to increase exponentially from 1.3 to 1.7 nm when the sample temperature was increased from 25 to 230 °C. Using simple approximations, we correlate this to an increase in the width of interfacial regions from 0.8 to 1.2 nm, while the volume fraction of interfacial regions increased from 31 to 44%. Using micro-compression measurements, we investigated the deformation behavior of ribbon glass and the corresponding nanoglass. While the nanoglass exhibited a remarkable plasticity even in the annealed state owing to the glass-glass interfaces, the corresponding ribbon glass was brittle. As this difference seems not limited to Sc₇₅Fe₂₅ glasses, the reported result suggest that nanoglasses open the way to glasses with high ductility resulting from the nanometer sized microstructure