Improved photocatalytic decolorization of reactive black 5 dye through synthesis of graphene quantum dots-nitrogen-doped TiO2.

Graphene quantum dots (GQDs), a new solid-state electron transfer material was anchored to nitrogen-doped TiO2 via sol gel method. The introduction of GQDs effectively extended light absorption of TiO2 from UV to visible region. GQD-N-TiO2 demonstrated lower PL intensity at excitation wavelengths of 320 to 450 nm confirming enhanced exciton lifespan. GQD-N-TiO2-300 revealed higher surface area (191.91m2 g-1), pore diameter (1.94 nm), TEM particle size distribution (4.88 ± 1.26 nm) with lattice spacing of 0.45 nm and bandgap (2.91 eV). In addition, GQDs incorporation shifted XPS spectrum of Ti 2p to lower binding energy level (458.36 eV), while substitution of oxygen sites in TiO2 lattice by carbon were confirmed through deconvolution of C 1 s spectrum. Photocatalytic reaction followed the pseudo first order reaction and continuous reductions in apparent rate constant (Kapp) with incremental increase in RB5 concentration. Langmuir-Hinshelwood model showed surface reaction rate constants KC = 1.95 mg L-1 min-1 and KLH = 0.76 L mg-1. The active species trapping, and mechanism studies indicated the photocatalytic decolorization of RB5 through GQD-N-TiO2 was governed by type II heterojunction. Overall, the photodecolorization reactions were triggered by the formation of holes and reactive oxygen species. The presence of •OH, 1O2, and O2• during the photocatalytic process were confirmed through EPR analysis. The excellent photocatalytic decolorization of the synthesized nanocomposite against RB5 can be ascribed to the presence of GQDs in the TiO2 lattice that acted as excellent electron transporter and photosensitizer. This study provides a basis for using nonmetal, abundant, and benign materials like graphene quantum dots to enhance the TiO2 photocatalytic efficiency, opening new possibilities for environmental applications.

Bentonite binding with mercury(II) ion through promotion of reactive oxygen species derived from manure-based dissolved organic matter.

This study reports the mercury binding by bentonite clay influenced by cattle manure-derived dissolved organic matter (DOM). The DOM (as total organic carbon; TOC) was reacted with bentonite at 5.2 pH to monitor the subsequent uptake of Hg2+ for 5 days. The binding kinetics of Hg2+ to the resulting composite was studied (metal = 350 µM/L, pH 5.2). Bentonite-DOM bound much more Hg2+ than original bentonite and accredited to the establishment of further binding sites. On the other hand, the presence of DOM was found to decrease the Hg2+ binding on the clay surface, specifically, the percent decrease of metal with increasing DOM concentration. Post to binding of DOM with bentonite resulted in increased particle size diameter (~ 33.37- ~ 87.67 nm) by inducing the mineral modification of the pore size distribution, thus increasing the binding sites. The XPS and FTIR results confirm the pronounced physico-chemical features of bentonite-DOM more than that of bentonite. Hydroxyl and oxygen vacancies on the surface were found actively involved in Hg2+ uptake by bentonite-DOM composite. Furthermore, DOM increased the content of Hg2+ binding by ~ 10% (pseudo-second-order qe = 90.9-100.0) through boosting up Fe3+ reduction with the DOM. The quenching experiment revealed that more oxygen functionalities were generated in bentonite-DOM, where hydroxyl was found to be dominant specie for Hg2+ binding. The findings of this study can be used as theoretical reference for mineral metal interaction under inhibitory or facilitating role of DOM, risk assessment, management, and mobilization/immobilization of mercury in organic matter-containing environment.

Recombinant B2L and Kisspeptin-54 DNA Vaccine Induces Immunity Against Orf Virus and Inhibits Spermatogenesis In Rats.

Orf is a highly contagious zoonotic disease of small ruminants caused by Parapoxvirus. Kisspeptin, encoded by the KISS1 gene with its cognate receptor GPR-54 is recognized as an upstream orchestrator in the hypothalamic-pituitary-gonadal axis. This study was designed to construct a DNA vaccine that produces a fused peptide composed of a major immunodominant protein of the orf virus (B2L) and kisspeptin-54, a neuropeptide with recognized roles in mammalian reproductive biology. The administration of this recombinant vaccine is shown to produce a significant antibody and cell-mediated immune response directed against B2L compared to the control group (p < 0.05). Furthermore, we found that rats inoculated with PBK-asd vaccine up-regulated antigen-mediated splenocyte proliferation and significantly raised antigen-specific tumor necrosis factor-alpha (TNFα-), interferon-gamma (IFN-ϒ) and interleukin (IL-2) compared to the control group (p < 0.05). This recombinant vaccine also stimulated antibody responses to kisspeptin and decreased serum luteinizing hormone and testosterone levels. Moreover, the current recombinant vaccine caused testicular atrophy and arrested spermatogenesis. It is concluded that this recombinant B2L and Kisspeptin-54 vaccine could be a promising approach for construction of bivalent orf virus and immunocastration vaccine. Furthermore, we concluded that the orf virus envelope protein (B2L) could be used as an immunomodulator for kisspeptin-54 to produce a strong antibody response.

Efficacy of nalmefene in preventing sufentanil-induced cough during induction of general anesthesia / 中华麻醉学杂志

Objective To evaluate the efficacy of nalmefene in preventing sufentanil-induced cough during induction of general anesthesia.Methods One hundred American Society of Anesthesiologists physical status Ⅰ orⅡ patients of both sexes,aged 21-62 yr,weighing 45-82 kg,undergoing elective laparoscopic cholecystectomy under general anesthesia,were divided into 2 groups (n =50 each) using a random number table:nalmefene group (group N) and control group (group C).Nalmefene 0.25 μg/kg was injected intravenously at 2 min before anesthesia induction in group N,and the equal volume of normal saline was given instead in group C.Anesthesia was induced with target-controlled infusion of propofol,and sufentanil 0.5 μg/kg was injected over 5 s when bispectral index value reached 55.The number of patients who developed cough within 2 min after sufentanil injection and severity of cough were observed.Other iv anesthetics were given for induction after the end of observation.Results The incidence of sufentanil-induced cough was 8％ in group N and 48％ in group C.Compared with group C,the incidence and severity of cough were significantly decreased in group N (P＜0.05).Conclusion Nalmefene 0.25 μg/kg injected at 2 min before induction of anesthesia can effectively decrease the development of sufentanil-induced cough during induction of general anesthesia.