Preparation of N-, O-, and S-tri-doped biochar through one-pot pyrolysis of poplar and urea formaldehyde and its enhanced removal of tetracycline from wastewater

In this study, biochar was prepared via hybrid doping of N, O, and S by applying one-pot pyrolysis of poplar wood and S-containing urea formaldehyde at 900 °C. Different doping ratios were adopted, and the contents of O, N, and S were in the ranges of 2.78 – 5.56 %, 2.16 – 4.92 %, and 1.42 – 4.98 %, respectively. This hybrid doping significantly enhanced the efficiency of the removal of tetracycline (40 mg/L) from wastewater to 71.84 % in comparison with that attained by using normal poplar biochar (29.45 %). The adsorption kinetics and isotherms indicated that the adsorption process was favorable and was dominated by chemisorption instead of physisorption; the dominant adsorption process may be justified by the existence of abundant functional groups. The adsorption capacity was barely related to the surface area (R2 = 0.478), while it was closely related to the concentration of graphitic N (R2 = 0.985) because graphitic N enhanced the π–π interactions. The adsorption capacity was also highly related to the proportion of oxidized N and oxidized S owing to hydrogen bonding, which may have overlapped with the contribution of O-containing functional groups. This study presents a simple hybrid doping method for biochar modification and provides fundamental insights into the specific effects of O-, N- and S-containing functional groups on the performance of biochar for tetracycline removal

Optical loss compensation in a bulk left-handed metamaterial by the gain in quantum dots

A bulk left-handed metamaterial with fishnet structure is investigated to show the optical loss compensation via surface plasmon amplification, with the assistance of a Gaussian gain in PbS quantum dots. The optical resonance enhancement around 200 THz is confirmed by the retrieval method. By exploring the dependence of propagation loss on the gain coefficient and metamaterial thickness, we verify numerically that the left-handed response can endure a large propagation thickness with ultralow and stable loss under a certain gain coefficient.Comment: 6 pages with 4 figure

The effects of afforestation on soil bacterial communities in temperate grassland are modulated by soil chemical properties

Grassland afforestation dramatically affects the abiotic, biotic, and ecological function properties of the original ecosystems. Interference from afforestation might disrupt the stasis of soil physicochemical properties and the dynamic balance of microbiota. Some studies have suggested low sensitivity of soil properties and bacterial community to afforestation, but the apparent lack of a significant relationship is probably due to the confounding effects of the generalist habitat and rare bacterial communities. In this study, soil chemical and prokaryotic properties in a 30-year-old Mongolia pine (Pinus sylvestris var. mongolica Litv.) afforested region and adjacent grassland in Inner Mongolia were classified and quantified. Our results indicate that the high richness of rare microbes accounts for the alpha-diversity of the soil microbiome. Few OTUs of generalist (core bacteria) and habitat-specialist bacteria are present. However, the high abundance of this small number of OTUs governs the beta-diversity of the grassland and afforested land bacterial communities. Afforestation has changed the soil chemical properties, thus indirectly affecting the soil bacterial composition rather than richness. The contents of soil P, Ca2+, and Fe3+ account for differentially abundant OTUs such as Planctomycetes and subsequent changes in the ecologically functional potential of soil bacterial communities due to grassland afforestation. We conclude that grassland afforestation has changed the chemical properties and composition of the soil and ecological functions of the soil bacterial community and that these effects of afforestation on the microbiome have been modulated by changes in soil chemical properties

Antimicrobial effects of free nitrous acid on Desulfovibrio vulgaris: Implications for sulfide-induced corrosion of concrete

Hydrogen sulfide produced by sulfate reducing bacteria (SRB) in sewers causes odor problems and asset deterioration due to the sulfide induced concrete corrosion. Free nitrous acid (FNA) was recently demonstrated as a promising antimicrobial agent to alleviate hydrogen sulfide production in sewers. However, knowledge of the antimicrobial mechanisms of FNA is largely unknown. Here we report the multiple-targeted antimicrobial effects of FNA on the SRB Desulfovibrio vulgaris Hildenborough by determining growth, physiological and gene expression responses to FNA exposure. The activities of growth, respiration and ATP generation were inhibited when exposed to FNA. These changes were reflected in transcript levels detected during exposure. Removal of FNA was evident by nitrite reduction that likely involved nitrite reductase and the poorly characterised hybrid cluster protein, and the genes coding for these proteins were highly expressed. During FNA exposure lowered ribosome activity and protein production were detected. Additionally, conditions within the cells were more oxidising and there was evidence of oxidative stress. Based on interpretation of the measured responses we present a model depicting the antimicrobial effects of FNA on D. vulgaris. These findings provide new insight for understanding the responses of D. vulgaris to FNA and will provide foundation for optimal application of this antimicrobial agent for improved control of sewer corrosion and odor management

Adolescent Exercise in Association with Mortality from All Causes, Cardiovascular Disease, and Cancer among Middle-Aged and Older Chinese Women

Background: Little is known regarding the role of early-life exercise, a potentially modifiable factor, in long-term adult morbidity and mortality. We utilized the Shanghai Women\u27s Health Study (SWHS) to investigate adolescent exercise in association with cancer, cardiovascular disease (CVD), and all-cause mortality among middle-aged and older women. Methods: The SWHS is a prospective cohort of 74,941 Chinese women ages 40 to 70 years recruited from 1996 to 2000. In-person interviews at enrollment assessed adolescent and adult exercise history, medical and reproductive history, and other lifestyle and socioeconomic (SES) factors. Mortality follow-up occurs via annual linkage to the Shanghai Vital Statistics Registry. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) were derived from Cox regression models. Results: Adjusting for birth year and other adolescent factors, adolescent exercise was associated with reduced risk of cancer, CVD, and total mortality [HRs (95% CI), 0.83 (0.72–0.95), 0.83 (0.70–0.98), and 0.78 (0.71–0.85), respectively for ≤1.33 hours (h)/week, and 0.83 (0.74–0.93), 0.62 (0.53–0.72), and 0.71 (0.66–0.77), respectively for \u3e1.33 h/week (reference = none)]. Results were attenuated after adjustment for adult SES and lifestyle factors. Participation in sports teams was inversely associated with cancer mortality [HR (95% CI), 0.86 (0.76–0.97)]. Joint adolescent and adult exercise was associated with reduced risk of all-cause, CVD, and cancer mortality [HRs (95% CIs), 0.80 (0.72–0.89), 0.83 (0.69–1.00), and 0.87 (0.74–1.01), respectively], adjusting for adult/adolescent factors, and adolescence exercise only was inversely associated with cancer mortality [HR (95% CI), 0.84 (0.71–0.98)]. Conclusions: Adolescent exercise participation, independent of adult exercise, was associated with reduced risk of cancer, CVD, and all-cause mortality. Impact: Results support promotion of exercise in adolescence to reduce mortality in later life

Complete genome sequencing and analysis of six enterovirus 71 strains with different clinical phenotypes

BACKGROUND: Hand, foot and mouth diseases (HFMD) caused by enterovirus 71(EV71) presents a broad spectrum of clinical manifestations ranging from mild febrile disease to fatal neurolocal disease. However, the mechanism of virulence is unknown. METHODS: We isolated 6 strains of EV71 from HFMD patients with or without neurological symptoms, and sequenced the whole genomes of the viruses to reveal the virulence factors of EV71. RESULTS: Phylogenetic tree based on VP1 region showed that all six strains clustered into C4a of C4 sub-genotype. In the complete polypeptide, 298 positions were found to be variable in all strains, and three of these positions (Val(P814)/Ile(P814) in VP1, Val(P1148)/Ile(P1148) in 3A and Ala (P1728)/Cys (P1728)/Val (P1728) in 3C) were conserved among the strains with neurovirulence, but variable in strains without neurovirulence. In the 5(′)-UTR region, it showed that the first 10 nucleotides were mostly conserved, however from the 11th nucleotide, nucleotide insertions and deletions were quite common. The secondary structure prediction of 5(′)-UTR sequences showed that two of three strains without neurovirulence (SDLY11 and SDLY48) were almost the same, and all strains with neurovirulence (SDLY96, SDLY107 and SDLY153) were different from each other. SDLY107 (a fatal strain) was found different from other strains on four positions (C(P241)/T(P241), A(P571)/T(P571), C(P579)/T(P579) in 5(′)-UTR and T(P7335)/C(P7335) in 3(′)-UTR). CONCLUSIONS: The three positions (Val(P814)/Ile(P814) in VP1, Val(P1148)/Ile(P1148) in 3A and Ala (P1728)/Cys (P1728)/Val (P1728) in 3C), were different between two phenotypes. These suggested that the three positions might be potential virulent positions. And the three varied positions were also found to be conserved in strains with neurovirulence, and variable in strains without neurovirulence. These might reveal that the conservation of two of the three positions or the three together were specific for the strains with neurovirulence. Varation of secondary structure of 5(′)-UTR, might be correlated to the changes of viral virulence. SDLY107 (a fatal strain) was found different from other strains on four positions, these positions might be related with death

Reconfigurable Meta-Radiator Based on Flexible Mechanically Controlled Current Distribution in Three-dimensional Space

In this paper, we provide an experimental proof-of-concept of this dynamic 3D current manipulation through a 3D-printed reconfigurable meta-radiator with periodically slotted current elements. By utilizing the working frequency and the mechanical configuration comprehensively, the radiation pattern can be switched among 12 states. Inspired by maximum likelihood method in digital communications, a robustness-analysis method is proposed to evaluate the potential error ratio between ideal cases and practice. Our work provides a previously unidentified model for next-generation information distribution and terahertz-infrared wireless communications

Resonance amplification of left-handed transmission at optical frequencies by stimulated emission of radiation in active metamaterials

We demonstrate that left-handed resonance transmission from metallic metamaterial, composed of periodically arranged double rings, can be extended to visible spectrum by introducing an active medium layer as the substrate. The severe ohmic loss inside metals at optical frequencies is compensated by stimulated emission of radiation in this active system. Due to the resonance amplification mechanism of recently proposed lasing spaser, the left-handed transmission band can be restored up to 610 nm wavelength, in dependence on the gain coefficient of the active layer. Additionally, threshold gains for different scaling levels of the double-ring unit are investigated to evaluate the gain requirement of left-handed transmission restoration at different frequency ranges.Comment: 12 pages, 5 figure