Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A.

Potential health risks related to environmental endocrine disruptors (EEDs) have aroused research hotspots at the forefront of water treatment technologies. Herein, nitrogen-doped titanium dioxide/schwertmannite nanocomposites (N-TiO2/SCH) have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes. Due to the sustainable Fe(III)/Fe(II) conversion induced by photoelectrons, as-prepared N-TiO2/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A (BPA; ca. 100% within 60 min under visible irradiation) in a wide pH range of 3.0-7.8, which is significantly higher than that of the pristine schwertmannite (ca. 74.5%) or N-TiO2 (ca. 10.8%). In this photo-Fenton system, the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical (•OH) and singlet oxygen (1O2). Moreover, the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses. This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts, but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

Unveiling the visible-light-driven photodegradation pathway and products toxicity of tetracycline in the system of Pt/BiVO4 nanosheets.

The antibiotics pollution has currently captured increasing concerns due to its potential hazards to the environment and human health. The development of efficient and viable techniques for the removal of antibiotics is one of the research hotspots in fields of wastewater treatment and pharmaceutical industry. Although the photodegradation of antibiotics is widely studied, the evolution and toxicity of degradation intermediates have been rarely documented. Herein, Pt nanoparticles (NPs) decorated BiVO4 nanosheets (Pt/BiVO4 NSs) that exhibit excellent tetracycline (TC) photodegradation activity and stability have been prepared. Especially, the TC degradation efficiency reaches ca. 88.5% after 60 min under visible light irradiation, which is superior to most of the metal loaded two-dimensional photocatalysts reported hitherto. The excellent photocatalytic activity is attributable to the enhanced light absorption capacity and charge separation efficiency in Pt/BiVO4 NSs. h+, •O2- and •OH are the main active species for TC degradation, resulting in three possible degradation pathways. Furthermore, we first verify that TC solutions treated by Pt/BiVO4 NSs are harmless to Escherichia coli K-12 and various bacteria in natural rivers, which would not stimulate Escherichia coli to produce antibiotics resistance genes (ARGs). This work develops an environmentally friendly photodegradation strategy using Pt/BiVO4 NSs with potentials for efficient remediation of antibiotics pollution in wastewater.

Predictive risk factors for recollapse of cemented vertebrae after percutaneous vertebroplasty: A meta-analysis.

BACKGROUND: As one of the most common complications of osteoporosis, osteoporotic vertebral compression fracture (OVCF) increases the risk of disability and mortality in elderly patients. Percutaneous vertebroplasty (PVP) is considered to be an effective, safe, and minimally invasive treatment for OVCFs. The recollapse of cemented vertebrae is one of the serious complications of PVP. However, the risk factors associated with recollapse after PVP remain controversial. AIM: To identify risk factors for the recollapse of cemented vertebrae after PVP in patients with OVCFs. METHODS: A systematic search in EMBASE, MEDLINE, the Cochrane Library, and PubMed was conducted for relevant studies from inception until March 2020. Studies investigating risk factors for the recollapse of cemented vertebrae after PVP without additional trauma were selected for analysis. Odds ratios (ORs) or standardized mean differences with 95% confidence interval (CI) were calculated and heterogeneity was assessed by both the chi-squared test and the I-squared test. The methodological quality of the included studies was assessed according to the Newcastle-Ottawa Scale. RESULTS: A total of nine case-control studies were included in our meta-analysis comprising 300 cases and 2674 controls. The significant risk factors for the recollapse of cemented vertebrae after PVP in OVCF patients were fractures located at the thoracolumbar junction (OR = 2.09; 95%CI: 1.30 to 3.38; P = 0.002), preoperative intravertebral cleft (OR = 2.97; 95%CI: 1.93 to 4.57; P < 0.00001), and solid lump distribution pattern of the cement (OR = 3.11; 95%CI: 1.91 to 5.07; P < 0.00001). The analysis did not support that age, gender, lumbar bone mineral density, preoperative visual analogue scale score, injected cement volume, intradiscal cement leakage, or vertebral height restoration could increase the risk for cemented vertebra recollapse after PVP in OVCFs. CONCLUSION: This meta-analysis suggests that thoracolumbar junction fractures, preoperative intravertebral cleft, and solid lump cement distribution pattern are associated with the recollapse of cemented vertebrae after PVP in OVCF patients.

High length-diameter ratio nanotubes self-assembled from a facial cyclopeptide.

A six-residue facial cyclopeptide was designed with the following sequence: c-[D-Leu-L-Lys-D-Ala-L-Lys-D-Leu-L-Gln] (CP). Extensive hydrogen bonding between the cyclopeptide backbones mainly regulated CP to self-assemble into single-walled nanotubes. Simultaneously, the hydrophobic interaction among facial hydrophobic side chains of CP was introduced to stabilize the hydrogen bonding, resulting in the formation of the thick-walled nanotubes with high length­diameter ratios.

Theranostic GO-based nanohybrid for tumor induced imaging and potential combinational tumor therapy.

Graphene oxide (GO)-based theranostic nanohybrid is designed for tumor induced imaging and potential combinational tumor therapy. The anti-tumor drug, Doxorubicin (DOX) is chemically conjugated to the poly(ethylenimine)-co-poly(ethylene glycol) (PEI-PEG) grafted GO via a MMP2-cleavable PLGLAG peptide linkage. The therapeutic efficacy of DOX is chemically locked and its intrinsic fluorescence is quenched by GO under normal physiological condition. Once stimulated by the MMP2 enzyme over-expressed in tumor tissues, the resulting peptide cleavage permits the unloading of DOX for tumor therapy and concurrent fluorescence recovery of DOX for in situ tumor cell imaging. Attractively, this PEI-bearing nanohybrid can mediate efficient DNA transfection and shows great potential for combinational drug/gene therapy. This tumor induced imaging and potential combinational therapy will open a window for tumor treatment by offering a unique theranostic approach through merging the diagnostic capability and pathology-responsive therapeutic function.

Hierarchical self-assembly of a ß-amyloid peptide derivative.

Neurodegenerative diseases including Alzheimer's, Parkinson's, and type II diabetes are recognized to be related to proteins misfolding into amyloid fibrils and other aggregates with a ß-sheet conformation. Herein, self-assembled peptide micro/nanoarchitectures were designed and prepared to mimic those aggregates. A short ß-amyloid peptide derivative with a diphenylalanine moiety was synthesized, which could self-assemble into nanofibers viaß-sheet conformation in an aqueous solution with a concentration of 1 mg mL-1 at pH about 8. By adjusting the pH to around 6.5, a peptide solution with a concentration of 15 mg mL-1 could change to a supramolecular hydrogel. The influence of self-assembly conditions including peptide concentration, temperature, pressure, and self-assembly time were investigated in detail. It was found that the self-assembled nanofibers could further aggregate into catenulate microfibers in solution as well as layer-by-layer plaques in the hydrogel under particular conditions.