A systematic approach was developed to understand, in-depth, the mechanisms involved during the inactivation of bacterial cells using photoelectrocatalytic (PEC) processes with Escherichia coli K-12 as the model microorganism. The bacterial cells were found to be inactivated and decomposed primarily due to attack from photogenerated H 2 O 2 . Extracellular reactive oxygen species (ROSs), such as H 2 O 2 , may penetrate into the bacterial cell and cause dramatically elevated intracellular ROSs levels, which would overwhelm the antioxidative capacity of bacterial protective enzymes such as superoxide dismutase and catalase. The activities of these two enzymes were found to decrease due to the ROSs attacks during PEC inactivation. Bacterial cell wall damage was then observed, including loss of cell membrane integrity and increased permeability, followed by the decomposition of cell envelope (demonstrated by scanning electronic microscope images). One of the bacterial building blocks, protein, was found to be oxidatively damaged due to the ROSs attacks, as well. Leakage of cytoplasm and biomolecules (bacterial building blocks such as proteins and nucleic acids) were evident during prolonged PEC inactivation process. The leaked cytoplasmic substances and cell debris could be further degraded and, ultimately, mineralized with prolonged PEC treatment.

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A new type of CDs with abundant carbonyl groups shows color-tunable ultralong phosphorescence from blue to red by self-doping, which was applied in information encryption and light detection.

A series of novel well-defined Ag/AgX (X = Cl, Br, I) loaded carbon nanotubes (CNTs) composite photocatalysts (Ag/AgX-CNTs) were fabricated for the first time via a facile ultrasonic assistant deposition−precipitation method at the room temperature (25 ± 1°C). X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption−desorption analysis, scanning electron microscopy, and ultraviolet−visible light absorption spectra analysis were used to characterize the structure, morphology, and optical properties of the asprepared photocatalysts. Results confirmed the existence of the direct interfacial contact between Ag/AgX nanoparticles and CNTs, and Ag/AgX-CNTs nanocomposites exhibit superior absorbance in the visible light (VL) region owing to the surface plasmon resonance (SPR) of Ag nanoparticles. The fabricated composite photocatalysts were employed to remove 2,4,6-tribromophenol (TBP) in aqueous phase. A remarkably enhanced VL photocatalytic degradation efficiency of Ag/AgX-CNTs nanocomposites was observed when compared to that of pure AgX or CNTs. The photocatalytic activity enhancement of Ag/AgX-CNTs was due to the effective electron transfer from photoexcited AgX and plasmon-excited Ag(0) nanoparticles to CNTs. This can effectively decrease the recombination of electron−hole pairs, lead to a prolonged lifetime of the photoholes that promotes the degradation efficiency. KEYWORDS: plasmonic photocatalyst, carbon nanotube supporter, silver halides, visible light, photocatalytic activity ■ INTRODUCTIONPhotocatalysis technique, as a cost-effective means for solar energy utilization, hydrogen production, and environmental purification, has been focused by many researchers. 1−7 In recent years, highly efficient visible-light-driven (VLD) photocatalyst development has been recognized as an important goal in the field of photocatalysis. Generally, two major approaches have been frequently employed to fabricate VLD photocatalyst. One is to modify TiO 2 -based photocatalyst to extend the light absorption spectrum from the UV to VL region by elements doping, 2 noble metal deposition, 3,8 12 Despite the noticeable progress, these VLD photocatalysts still have some drawbacks, such as relatively low VL photocatalytic activity and poor stability, limiting their practical applications. It is therefore highly desirable to develop highly efficient VLD photocatalysts that could meet the needs for applications in environmental and energy fields.Currently, the localized surface plasmon resonance (SPR) effect of noble-metal nanoparticles (e.g., Ag and Au) has become a research focus in the development of VLD photocatalysts. 13 The VL activity of plasmonic photocatalyst is originated from the distinctive plasmon resonance effect in VL region that has been well demonstrated for metallic Au and Ag nanoparticles. 4,14−19 Also a number of Ag/AgX (X = Cl, Br)-based materials, such as graphene sheets grafted Ag/AgCl, 1 graphene oxide (GO) enwrapped Ag/AgX (X = Cl, Br) nanocomposite, 16 Ag/AgBr@TiO 2 , 18 Ag/AgCl@H 2 WO...

Compared to planar carbazole, the molecular conjugation of iminodibenzyl (Id) was destroyed by a C-C bond and a twisted structure was formed, which exhibited blue-shifted ultralong phosphorescence with a lifetime of 402 ms in a crystal under ambient conditions. For the presence of an oscillating C-C bond between the two benzene rings in Id, more than one molecular configuration in the crystal was discovered by X-ray single-crystal analysis. Moreover, its ultralong phosphorescence color changed from blue to green by varying the excitation wavelength in solution at 77 K. Theoretical calculations also confirmed that different molecular configurations had certain impact on the phosphorescent photophysical properties. This result will allow a major step forward in expanding the scope of ultralong organic phosphorescent (UOP) materials, building a bridge to realize the relationship between molecular structure and UOP property.

The characteristics of volatile compounds from five different bacterial species, Escherichia coli O157:H7, Salmonella Enteritidis, Shigella flexneri, Staphylococcus aureus, and Listeria monocytogenes, growing, respectively, in trypticase soy broth were monitored by headspace solid-phase micro-extraction/gas chromatography-mass spectrometry. The results showed that most volatile organic compounds (VOCs) of five pathogens started to increase after the sixth to tenth hour. Methyl ketones and long chain alcohols were representative volatiles for three Gram-negative bacteria. The especially high production of indole was characterized to E. coli O157:H7. The production of 3-hydroxy-2-butanone was indicative of the presence of two Gram-positive bacteria. Both 3-methyl-butanoic acid and 3-methyl-butanal were unique biomarkers for S. aureus. The population dynamics of individual pathogen could be monitored using the accumulation of VOCs correlated with its growth. And these five pathogens could be distinguishable though principle component analysis of 18 volatile metabolites. Moreover, the mixed culture of S. aureus and E. coli O157:H7 was also investigated. The levels of 3-methyl-butanal and 3-methyl-butanoic acid were largely reduced; while the level of indole almost unchanged and correlated with E. coli O157:H7 growth very well. The characteristics of volatiles from the five foodborne pathogens could lay a fundamental basis for further research into pathogen contamination control by detecting volatile signatures of pathogens.

Bacillus amyloliquefaciens FZB42 has been shown to stimulate plant growth and to suppress the growth of plant pathogenic organisms including nematodes. However, the mechanism underlying its effect against nematodes remains unknown. In this study, we screened a random mutant library of B. amyloliquefaciens FZB42 generated by the mariner transposon TnYLB-1 and identified a mutant strain F5 with attenuated nematicidal activity. Reversible polymerase chain reaction revealed that three candidate genes RAMB_007470, yhdY, and prkA that were disrupted by the transposon in strain F5 potentially contributed to its decreased nematicidal activity. Bioassay of mutants impaired in the three candidate genes demonstrated that directed deletion of gene RBAM_007470 resulted in loss of nematicidal activity comparable with that of the F5 triple mutant. RBAM_007470 has been reported as being involved in biosynthesis of plantazolicin, a thiazole/oxazole-modified microcin with hitherto unknown function. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) analyses of surface extracts revealed that plantazolicin bearing a molecular weight of 1,354 Da was present in wild-type B. amyloliquefaciens FZB42, but absent in the ΔRABM_007470 mutant. Furthermore, bioassay of the organic extract containing plantazolicin also showed a moderate nematicidal activity. We conclude that a novel gene RBAM_007470 and its related metabolite are involved in the antagonistic effect exerted by B. amyloliquefaciens FZB42 against nematodes.

ABO 3-type perovskites (A=La, Ce, Sm; B=Cr, Mn, Fe, Co, Ni) were systematically fabricated via a facile soft-templated sol-gel with post-calcination method through a complexation-carbonation-oxidation process, which were successfully applied in the visible-light-driven photothermocatalytic degradation of volatile organic compounds (VOCs) for the first time. Preliminary characterization results revealed the lower impact to the oxidative performance and visible-light-absorption properties of ANiO 3 than LaBO 3 , while the latter ones should present more attractive promotion of catalytic performance toward VOC degradation. Subsequently catalytic degradation of VOCs using gaseous styrene as model compound confirmed that all LaBO 3-type perovskites possessed both high visible-light-driven photocatalytic and temperature-induced thermocatalytic activities. Meanwhile, synergetic effect between photocatalysis and thermocatalysis activities of different position B substituted LaBO 3 resulted in different enhancement of their photothermocatalytic activities, where the highest synergistic factor (3.53) was obtained for LaMnO 3 at 140 o C. Besides, the synergetic effect could also effectively preserve the activity of the perovskite catalysts (eg. LaMnO 3) that almost the same removal efficiency (ca. 96.6% within 40 min) was obtained to styrene (initial concentration of 40 ppmv) after five continuous cycling tests. The highly and stably photothermocatalytic activity of these perovskites were attributed to the coefficient effect of the small crystal size and narrower bandgap as well as high visible light absorption and reducibility. This work could provide an efficient and practical way to utilize the total energy of sun for the remediation of atmospheric environment pollutions.