Quantitative microbial risk assessment and sensitivity analysis for workers exposed to pathogenic bacterial bioaerosols under various aeration modes in two wastewater treatment plants.

Wastewater treatment plants (WWTPs) could emit a large amount of bioaerosols containing pathogenic bacteria. Assessing the health risks of exposure to these bioaerosols by using quantitative microbial risk assessment (QMRA) is important to protect workers in WWTPs. However, the relative impacts of the stochastic input variables on the health risks determined in QMRA remain vague. Hence, this study performed a Monte Carlo simulation-based QMRA case study for workers exposing to S. aureus or E. coli bioaerosols and a sensitivity analysis in two WWTPs with various aeration modes. Results showed that when workers equipped without personal protective equipment (PPE) were exposed to S. aureus or E. coli bioaerosol in the two WWTPs, the annual probability of infection considerably exceeded the U.S. EPA benchmark (≤10E-4 pppy), and the disease burden did not satisfy the WHO benchmark (≤10E-6 DALYs pppy) (except exposure to E. coli bioaerosol for disease health risk burden). Nevertheless, the use of PPE effectively reduced the annual infection health risk to an acceptable level and converted the disease health risk burden to a highly acceptable level. Referring to the sensitivity analysis, the contribution of mechanical aeration modes to the variability of the health risks was absolutely dominated in the WWTPs. On the aeration mode that showed high exposure concentration, the three input exposure parameters (exposure time, aerosol ingestion rate, and breathing rate) had a great impact on health risks. The health risks were also prone to being highly influenced by the various choices of the dose-response model and related parameters. Current research systematically delivered new data and a novel perspective on the sensitivity analysis of QMRA. Then, management decisions could be executed by authorities on the basis of the results of this sensitivity analysis to reduce related occupational health risks of workers in WWTPs.

Synthesis and Imaging of Biocompatible Graphdiyne Quantum Dots.

Graphdiyne has attracted much interest from researchers for their potential applications in energy storage, catalysis, and biomedical areas. As one of the derivatives of graphdiyne, graphdiyne quantum dots (GDQDs) may possess superior bioactivity due to active acetylene units. However, the biological application of biocompatible GDQDs have not been reported so far. Herein, GDQDs with uniform size and good crystallization were prepared via a classical solvothermal method. The GDQDs exhibit excitation- and pH-dependent fluorescence emission as well as superior photostability, demonstrating their potential for bioimaging. The GDQDs demonstrate efficient cellular uptake and cell imaging without induction of detectable cytotoxic effects in vitro. Systematical safety evaluation further confirmed good biocompatibility of the GDQDs in vivo. Our study preliminarily validates the application of the GDQDs in biomedicine and encourages more thorough studies for better realizing the potential of GDQDs.

Intensified C≡C Stretching Vibrator and Its Potential Role in Monitoring Ultrafast Energy Transfer in 2D Carbon Material by Nonlinear Vibrational Spectroscopy.

In this work, an intensity-enhanced C≡C stretching infrared (IR) absorption is observed in hexakis[(trimethylsilyl)ethynyl]benzene (HTEB), whose IR transition dipole magnitude becomes comparable to that of a typical C═O stretch, and the enhancement is believed to be due to a joint effect of π-π conjugation and hyperconjugation associated with a terminal trimethylsilyl group. Using dynamical time-dependent two-dimensional infrared (2D IR) spectroscopy, a picosecond intramolecular energy redistribution process is observed between two nondegenerate C≡C stretching modes, whose symmetry breaking is attributed to a noncovalent halogen-bonding interaction between HTEB and solvent CH2Cl2. The rigid structure of HTEB and limited structural dynamics are also inferred from the insignificant initial spectral diffusion value extracted from the 2D IR spectra. This work provides the first nonlinear infrared investigation of the conventionally weak C≡C stretch. The methods outlined are particularly important for detailed understanding of the structure-related processes such as vibrational energy transfer in novel C≡C species containing materials such as graphdiyne.

Graphdiyne Sponge for Direct Collection of Oils from Water.

Although several sponge-like sorbents have been developed to treat oil spills and chemical leakages, under harsh conditions (e.g., strong acid or alkali; oils on the sea) their efficiencies can be rather limited. Herein, we provide a graphdiyne sponge that is capable of collecting oil pollution effectively. This graphdiyne sponge exhibits excellent adsorption capacity (up to 160 times its own weight), robust stability (even when immersed in strong acid and alkali for 7 days), and remarkable recyclability (up to 100 times). These features suggest that this new adsorbent material might find applicability in the cleanup of oil spills and many organic pollutants under realistic conditions.

A facile approach for graphdiyne preparation under atmosphere for an advanced battery anode.

An explosion approach was developed for efficiently preparing graphdiynes (GDYs) at 120 °C in air without any metal catalyst. The GDYs show great superiority in terms of thermal stability, conductivity (20 S m-1) and surface area (up to 1150 m2 g-1), and can be applied as promising anodes for storing lithium/sodium ions.

Superlyophilicity-Facilitated Synthesis Reaction at the Microscale: Ordered Graphdiyne Stripe Arrays.

As a new member of carbon allotropes, graphdiyne is a promising material with excellent electronic performance and high elasticity, indicating the possibility of graphdiyne to serve as the building blocks in flexible electronics. However, precise positioning/patterning of graphdiyne is still a challenge for the realization of large-area and flexible organic electronic devices and circuits. Here, the direct in situ synthesis of patterning graphdiyne stripe arrays dominated by the superlyophilic grooved templates is reported, whereas the superlyophilicity of grooved templates plays a key role in allowing continuous mass transport of raw reactants into the microscale spacing. After the completion of cross-coupling reaction procedure, precisely patterned graphdiyne stripes can be generated accordingly. The size of graphdiyne stripe arrays is depending on the silicon substrate size (1 cm × 1.5 cm), and the layer thickness can be manipulated from just several nanometers to hundreds of nanometers by varying the primary concentration of hexaethynylbenzene monomers. As a proof-of-principle demonstration, a stretchable sensor based on the graphdiyne stripe arrays is performed to monitor the human finger motion. It is expected that this wettability-facilitated strategy will provide new insights into the controlled synthesis of graphdiyne toward promising flexible electronics and other optoelectronic applications.

Controlling the Interface Areas of Organic/Inorganic Semiconductor Heterojunction Nanowires for High-Performance Diodes.

A new method of in situ electrically induced self-assembly technology combined with electrochemical deposition has been developed for the controllable preparation of organic/inorganic core/shell semiconductor heterojunction nanowire arrays. The size of the interface of the heterojunction nanowire can be tuned by the growing parameter. The heterojunction nanowires of graphdiyne/CuS with core/shell structure showed the strong dependence of rectification ratio and perfect diode performance on the size of the interface. It will be a new way for controlling the structures and properties of one-dimensional heterojunction nanomaterials.

Graphdiyne:ZnO Nanocomposites for High-Performance UV Photodetectors.

Graphdiyne (GD), a novel carbon allotrope with a 2D structure comprising benzene rings and carbon-carbon triple bonds, is successfully integrated with ZnO nanoparticles by a wet chemistry method. An ultraviolet photodetector based on these graphdiyne:ZnO nanocomposites exhibits significantly enhanced performance in comparison with a conventional ZnO device. GD may have diverse applications in future optoelectronics.

Tuning the luminescence behaviors of a chloroplatinum(II) complex by component exchanges of dynamic acylhydrazone bonds.

A cationic chloroplatinum(II) complex was found to show remarkable luminescence enhancement upon self-assembly with tripodal dynamic acylhydrazone-bridged sulfonates in water. The successive exchange reactions with acylhydrazine or aldehyde resulted in a controllable decrease in the luminescence intensities.