Elimination of inhibitory effects of dodecyl dimethyl benzyl ammonium chloride on microalgae in wastewater by cocultivation with a newly screened microbial consortium.

As one of the most commonly used biocidal cationic surfactants, benzalkonium chlorides (BACs) have been an increasing concern as emerging contaminants. Wastewater has been claimed the main point for BACs to enter into the environment, but to date, it is still largely unknown how the BACs affect the microbes (especially microalgae) in the practical wastewater and how to cost-effectively remove them. In this study, the inhibitory effects of a typical BACs, dodecyl dimethyl benzyl ammonium chloride (DDBAC), on a green microalga Chlorella sp. in oxidation pond wastewater were investigated. The results showed that though a hermetic effect at the first 2 days was observed with the DDBAC at low concentration (<6 mg/L), the algal growth and photosynthesis were significantly inhibited by the DDBAC at all the tested concentrations (3 to 48 mg/L). Fortunately, a new microbial consortium (MC) capable of degrading DDBAC was screened through a gradient domestication method. The MC mainly composed of Wickerhamomyces sp., Purpureocillium sp., and Achromobacter sp., and its maximum removal efficiency and removal rate of DDBAC (48 mg/L) respectively reached 98.1 % and 46.32 mg/L/d. Interestingly, a microbial-microalgal system (MMS) was constructed using the MC and Chlorella sp., and a synergetic effect between the two kinds of microorganisms was proposed: microalga provided oxygen and extracellular polysaccharides as co-metabolic substrates to help the MC to degrade DDBAC, while the MC helped to eliminate the DDBAC-induced inhibition on the alga. Further, by observing the seven kinds of degradation products (mainly including CH5O3P, C6H5CH2-, and C8H11N), two possible chemical pathways of the DDBAC degradation were proposed. In addition, the metagenomic sequencing results showed that the main functional genes of the MMS included antibiotic-resistant genes, ABC transporter genes, quorum sensing genes, two-component regulatory system genes, etc. This study provided some theoretical and application findings for the cost-effective pollution prevention of BACs in wastewater.

Effect of CrF3 Addition on Photoluminescence Properties of Lead-Free Cs4SnBr6-xFx Zero-Dimensional Perovskite.

Zero-dimensional (0D) tin halide perovskites, characterized by their broadband and adjustable emissions, high photoluminescence quantum yield, and absence of self-absorption, are crucial for the fabrication of high-efficiency optoelectronic devices, such as LEDs, solar cells, and sensors. Despite these attributes, boosting their emission efficiency and stability poses a significant challenge. In this work, Cr3+-doped Cs4SnBr6-xFx perovskites were synthesized using a water-assisted wet ball-milling method. The effect of CrF3 addition on photoluminescence properties of Cs4SnBr6-xFx Perovskites was investigated. We found that Cr3+-doped Cs4SnBr6-xFx Perovskites exhibit a broad emission band, a substantial Stokes shift, and an efficient green light emission centered at about 525 nm at ambient temperature. The derived photoluminescence quantum yield amounted to as high as 56.3%. In addition, these Cr3+-doped Cs4SnBr6-xFx perovskites outperform their undoped counterparts in terms of thermal stability. Through a comprehensive analysis of photoluminescence measurements, our findings suggested that the elevated photoluminescence quantum yield can be attributed to the enhanced exciton binding energy of self-trapped excitons (STEs) and the suitable electron-phonon coupling resulting from the substantial distortion of [SnBr6]4- octahedra instigated by the addition of CrF3.

Synthesis and Improved Photoluminescence of SnF2-Derived CsSnCl3-SnF2:Mn2+ Perovskites via Rapid Thermal Treatment.

We report a rapid synthesis method for producing CsSnCl3:Mn2+ perovskites, derived from SnF2, and investigate the effects of rapid thermal treatment on their photoluminescence properties. Our study shows that the initial CsSnCl3:Mn2+ samples exhibit a double luminescence peak structure with PL peaks at approximately 450 nm and 640 nm, respectively. These peaks originate from defect-related luminescent centers and the 4T1→6A1 transition of Mn2+. However, as a result of rapid thermal treatment, the blue emission is significantly reduced and the red emission intensity is increased nearly twofold compared to the pristine sample. Furthermore, the Mn2+-doped samples demonstrate excellent thermal stability after the rapid thermal treatment. We suggest that this improvement in photoluminescence results from enhanced excited-state density, energy transfer between defects and the Mn2+ state, as well as the reduction of nonradiative recombination centers. Our findings provide valuable insights into the luminescence dynamics of Mn2+-doped CsSnCl3 and open up new possibilities for controlling and optimizing the emission of rare-earth-doped CsSnCl3.

Application of α-Fe2O3 nanoparticles in controlling antibiotic resistance gene transport and interception in porous media.

Metal oxide nanoparticles (MONPs) with a large specific surface area are expected to bind with antibiotic resistance genes (ARGs), thereby controlling ARGs' contamination by reducing their concentration and mobilization. Here, adsorption experiments were carried out and it was found that α-Fe2O3 NPs could chemically bind with ARGs (tetM-carrying plasmids) in water with an adsorption rate of 0.04 min-1 and an adsorption capacity of 7.88 g/kg. Mixing α-Fe2O3 NPs into quartz sand column markedly increased the interceptive removal of ARGs from inflow water. The interception rate of 1.0 µg/mL ARGs in ultrapure water (25 mL, 5 pore volumes) through the sand column (plexiglass, length 8 cm, internal diameter 1.4 cm) with 1 g/kg α-Fe2O3 NPs was 1.73 times of that through the pure sand column; the interception rate overall increased with increasing addition of α-Fe2O3 NPs, reaching 68.8% with 20 g/kg α-Fe2O3 NPs. Coexisting Na+ (20 mM), Ca2+ (20 mM), and acidic condition (pH 4.0) could further increase the interception rate of ARGs by 1 g/kg α-Fe2O3 NPs from 21.1% to 86.2%, 90.7%, and 96.2%, respectively. The presence of PO43- and humic acid at environmentally relevant concentrations would not significantly affect the interception of ARGs. In the treatment groups with PO43- and humic acid, the removal rate decreased by only 1.8% and 0.1%, respectively. In addition, the interceptive removal of ARGs by α-Fe2O3 NPs-incorporated sand column was even better in actual surface water samples (87.2%) than that in the ultrapure water (21.1%). The findings provide a promising approach to treat ARGs-polluted water.

Binding Force and Site-Determined Desorption and Fragmentation of Antibiotic Resistance Genes from Metallic Nanomaterials.

Interfacial interactions between antibiotic resistance genes (ARGs) and metallic nanomaterials (NMs) lead to adsorption and fragmentation of ARGs, which can provide new avenues for selecting NMs to control ARGs. This study compared the adsorptive interactions of ARGs (tetM-carrying plasmids) with two metallic NMs (ca. 20 nm), i.e., titanium dioxide (nTiO2) and zero-valent iron (nZVI). nZVI had a higher adsorption rate (0.06 min-1) and capacity (4.29 mg/g) for ARGs than nTiO2 (0.05 min-1 and 2.15 mg/g, respectively). No desorption of ARGs from either NMs was observed in the adsorptive background solution, isopropanol or urea solutions, but nZVI- and nTiO2-adsorbed ARGs were effectively desorbed in NaOH and NaH2PO4 solutions, respectively. Molecular dynamics simulation revealed that nTiO2 mainly bound with ARGs through electrostatic attraction, while nZVI bound with PO43- of the ARG phosphate backbones through Fe-O-P coordination. The ARGs desorbed from nTiO2 remained intact, while the desorbed ARGs from nZVI were splintered into small fragments irrelevant to DNA base composition or sequence location. The ARG removal by nZVI remained effective in the presence of PO43-, natural organic matter, or protein at environmentally relevant concentrations and in surface water samples. These findings indicate that nZVI can be a promising nanomaterial to treat ARG pollution.

X-linked inhibitor of apoptosis protein accelerates migration by inducing epithelial-mesenchymal transition through TGF-ß signaling pathway in esophageal cancer cells.

BACKGROUND: The prognosis of esophageal cancer is still dismal because of its high probability of metastasis that is likely related to the cellular process of epithelial-mesenchymal transition (EMT). Recent studies have shown a novel role of X-linked inhibitor of apoptosis protein (XIAP) in regulating the migration process of cancer cells and, therefore, linking to progression and poor prognosis of cancer. METHODS: The expression of XIAP in esophageal squamous cell cancer (ESCC) tissues was determined by immunohistochemistry assay. Cell migration was analyzed by wound healing assay and Transwell assay. The expression of EMT markers (E-cadherin, N-cadherin and Vimentin) was revealed by immunofluorescence assay. Quantitative real­time PCR analysis and Western blot analysis were used to detect the expression of XIAP and EMT markers as well as transforming growth factor-ß (TGF-ß) at mRNA and protein level, respectively. RESULTS: We found that the expression of XIAP closely correlated to the probability of lymphatic metastasis in patients and that ESCC patients with the high XIAP expression were associated with worse overall survival (OS). Univariate and multivariate analysis also revealed XIAP as an independent prognostic factor for overall survival in ESCC patients. In both EC9706 and TE13 cell lines, knockdown of XIAP decreased the migration of cancer cells by inhibiting EMT process through regulating the TGF-ß signaling pathway, pinpointing a regulatory role of XIAP in migratory process upon TGF-ß activation. CONCLUSIONS: Taken together, our results suggest XIAP as a important prognostic and regulative factor in ESCC patients. XIAP may promote migration of esophageal cancer cells through the activation of TGF-ß mediated EMT.

Retrospective Comparison of Two Minimally Invasive Esophagectomy in the Treatment of Esophageal Cancer: Pneumatic Mediastinoscopy Versus Thoracoscopy.

Objective: To compare the clinical effectiveness of two approaches of minimally invasive esophagectomy (MIE) in esophagectomy patients. Materials and Methods: We retrospectively screened the perioperative data in a total of 49 patients who underwent MIE. Among them, 30 patients underwent thoracoscopy combined with laparoscopy (Group A), while the rest received mediastinoscopy combined with laparoscopy (Group B). Clinical effectiveness and postoperative complications were comparatively analyzed. Results: The patients with mediastinoscopy showed a shorter average surgical time, less blood loss during surgery, diminished drainage volume in the first 3 days after surgery, and reduced hospitalization time, compared with the patients with thoracoscopic approach (P < .05). However, the mediastinoscopic route seems to render a higher incidence of postoperative hoarseness than thoracoscopy combined with laparoscopy (P < .05). In mediastinal lymph node dissection, the number of right recurrent laryngeal nerve lymph nodes (RLN LNs) in mediastinoscopic route was significantly less than that of thoracoscopy (P < .05). Conclusion: Mediastinoscopy was less invasive, with shorter surgical time, faster recovery, and better patient comfort, although it had certain limitations in the dissection of right RLN LNs. It is beneficial to patients with poor pulmonary function and no obvious mediastinal lymphadenectasis.