Persistent pollution of genetic materials in a typical laboratory environment.

From the onset of coronavirus disease (COVID-19) pandemic, there are concerns regarding the disease spread and environmental pollution of biohazard since studies on genetic engineering flourish and numerous genetic materials were used such as the nucleic acid test of the severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this work, we studied genetic material pollution in an institute during a development cycle of plasmid, one of typical genetic materials, with typical laboratory settings. The pollution source, transmission routes, and pollution levels in laboratory environment were examined. The Real-Time quantitative- Polymerase Chain Reaction results of all environmental mediums (surface, aerosol, and liquid) showed that a targeted DNA segment occurred along with routine experimental operations. Among the 79 surface and air samples collected in the genetic material operation, half of the environment samples (38 of 79) are positive for nucleic acid pollution. Persistent nucleic acid contaminations were observed in all tested laboratories and spread in the public area (hallway). The highest concentration for liquid and surface samples were 1.92 × 108 copies/uL and 5.22 × 107 copies/cm2, respectively. Significant amounts of the targeted gene (with a mean value of 74 copies/L) were detected in the indoor air of laboratories utilizing centrifuge devices, shaking tables, and cell homogenizers. Spills and improper disposal of plasmid products were primary sources of pollution. The importance of establishing designated experimental zones, employing advanced biosafety cabinets, and implementing highly efficient cleaning systems in laboratories with lower biosafety levels is underscored. SYNOPSIS: STATEMENT. Persistent environmental pollutions of genetic materials are introduced by typical experiments in laboratories with low biosafety level.

Extrusion puffing as a pretreatment method to change the surface structure, physicochemical properties and in vitro protein digestibility of distillers dried grains with solubles.

BACKGROUND: Distillers dried grains with solubles (DDGS) are rich in nutrition, and they are potential protein feed raw material. However, the existence of cellulose, hemicellulose and lignin hinders animals' digestion and absorption of DDGS. Making full use of unconventional feed resources such as DDGS can alleviate the shortage of feed resources to a certain extent. This research investigated the effects of twin-screw extrusion on the macromolecular composition, physical and chemical properties, surface structure and in vitro protein digestibility (IVPD) of DDGS. RESULTS: The findings showed that extrusion puffing significantly increased the protein solubility, bulk density, water holding capacity, and swelling capacity, while significantly decreased hemicellulose and crude protein content, particle size and zeta potential of DDGS. The structure damage of DDGS induced by the extrusion was characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FITR) spectroscopy and X-ray diffraction (XRD) analysis. Interestingly, no random coil was observed in the analysis of the secondary structure, and extrusion promoted the transformation of α-helix and ß-turn to ß-sheet, which led to significant increases in protein solubility and IVPD of DDGS (P < 0.05). Additionally, correlation analysis revealed that IVPD and PS had a positive relationship. CONCLUSION: Extrusion puffing was an ideal pretreatment method for DDGS modification to improve in vitro protein digestibility. © 2023 Society of Chemical Industry.

Synergistic Surface Defect Passivation of Ionic Liquids for Efficient and Stable MAPbI3-Based Inverted Perovskite Solar Cells.

Organic-inorganic hybrid perovskite solar cells are fabricated using polycrystalline perovskite thin films, which possess high densities of point and surface defects. The surface defects of perovskite thin films are the key factors that affect the device performance. Therefore, the reduction of harmful defects is the primary task for improving device performance. Therefore, in this study, high-quality perovskite thin films are prepared using an ionic liquid, dithiocarbamate diethylamine (DADA), to passivate the interface. The electron-rich sulfur atom in the DADA molecule chelates with the uncoordinated lead ion in the perovskite films, and the diethylammonium cation forms a hydrogen bond with the free iodine ion, which further improves the passivation. The synergistic passivation and improved morphology of the perovskite thin films substantially reduce the number of charged defects on the film surface and prolong the carrier lifetime. In addition, the DADA surface treatment increases the work function of the perovskite film, which is beneficial for carrier transport. Under standard solar-lighting conditions, the power conversion efficiency (PCE) of the device increases from 19.13 to 21.36%, and the fill factor is as high as 83.17%. Owing to both the hydrophobicity of DADA molecules and the passivation of ion defects, the PCE of the device remains above 80%, even for the device stored for 500 h in air at a relative humidity of 65%, and the device stability is substantially improved.

AgMAsS3 (M = Cd, Hg): Double d10 Cation-Containing Thioarsenites(III) Exhibiting High Photocurrent Response and Moderate Second Harmonic Generation.

Thioarsenites(III) are an advanced functional material platform owing to the stereochemically active lone pair cations. In this paper, two novel quaternary thioarsenites(III), AgMAsS3 (M = Cd, Hg), are successfully obtained by introducing double d10 cations. In the compounds, d10 cations show a variety of different coordination modes ([AgS4] and [HgS4] in AgHgAsS3 vs [AgS5] and [CdS6] in AgCdAsS3). As a result, AgHgAsS3 and AgCdAsS3 crystallize in the noncentrosymmetric Cc space group and centrosymmetric C2/c space group, respectively. The band gaps of AgHgAsS3 and AgCdAsS3 are determined experimentally as 1.90 and 2.20 eV, respectively. Meanwhile, title compounds exhibit strong photocurrent responses. Specifically, AgHgAsS3 has a large birefringence of 0.18 at 2100 nm and a moderate second harmonic generation of (0.5 × AgGaS2). Moreover, the origin of linear and nonlinear optical responses is investigated based on first-principles calculations. This study enriches the family of MI-MII-As-Q (M = Ag, Cu; MII = Zn, Cd, Hg; Q = chalcogen) chalcogenides and helps to understand and design other multifunctional optical materials.

Ultrastable 3D cage-like metal-organic frameworks constructed using polydentate cyanurate ligands and their gas adsorption properties.

Stability is a key factor that restricts the practical applications of metal-organic framework (MOF) materials. In this work, we report an ultrastable three-dimensional cage-like MOF, SrCu(HC3N3O3)2, constructed by a polydentate cyanurate ligand and two kinds of different metal nodes. A high ratio of coordination sites in organic ligands, specific coordination of strong acid with a strong base and weak acid with a weak base and double independent completed coordination networks endow SrCu(HC3N3O3)2 with outstanding thermal stability (up to 300 °C) and acid/alkali resistance (pH = 2-14). Moreover, SrCu(HC3N3O3)2 possesses the highest porosity up to 36.7% among cyanuric acid-based MOF materials and exhibits differentiated adsorption of C3H4 (63 cm3 g-1) and C3H6 (51 cm3 g-1). The breakthrough experiment further verified that efficient C3H4/C3H6 separation can be achieved under dynamic conditions by SrCu(HC3N3O3)2.

Quaternary alkaline-earth metal thiophosphate SrAgPS4: syntheses, structures, and optical properties.

Metal thiophosphates have outstanding properties for the generation of mid-infrared coherent light and are an emerging nonlinear optical material system. In this study, a new non-centrosymmetric (NCS) quaternary alkaline-earth metal thiophosphate, SrAgPS4, was obtained via a high-temperature solid-state method. The new compound crystallizes in the NCS Ama2 (No. 40) space group and features two-dimensional [AgPS4]2- layers consisting of alternately connected [PS4] and [AgS4] tetrahedra. SrAgPS4 exhibits a strong phase-matched second harmonic generation response (1.10 × AgGaS2 at 2100 nm) and a large band gap (2.97 eV). In addition, theoretical calculations reveal the intrinsic relationship between the electronic structure and optical properties. This work enriches and greatly promotes the research on infrared nonlinear optical materials based on thiophosphates.

Multifunctional Molecule Assists Passivate Method to Simultaneously Improve the Efficiency and Stability of Perovskite Solar Cells.

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been greatly improved recently. However, in organic-inorganic polycrystalline perovskite films many defects inevitably exist, which limits the PCE and stability of PSCs. Herein, a small organic molecule 2-chlorothiazole-4-carboxylic acid (SN) is spin coated on a perovskite film to enhance the performance of PSCs. We find that the multifunctional molecule SN reacts with under-coordinated Pb2+ ions and I- vacancies because of the presence of the sulfur and nitrogen donor atoms, and the -COOH groups, which are conducive to suppressing charge recombination and passivating defects. Even more, the introduction of the SN layer can effectively adjust the energy level alignment, which is conducive to the separation and extraction of charge carriers in PSCs. Therefore, devices with SN modification show a champion PCE of 22.55 %. Besides, PSCs with SN show impressive stability, retaining 96 % of its initial PCE after storage in ambient air for 500 h.

Two pan-SARS-CoV-2 nanobodies and their multivalent derivatives effectively prevent Omicron infections in mice.

With the widespread vaccinations against coronavirus disease 2019 (COVID-19), we are witnessing gradually waning neutralizing antibodies and increasing cases of breakthrough infections, necessitating the development of drugs aside from vaccines, particularly ones that can be administered outside of hospitals. Here, we present two cross-reactive nanobodies (R14 and S43) and their multivalent derivatives, including decameric ones (fused to the immunoglobulin M [IgM] Fc) that maintain potent neutralizing activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after aerosolization and display not only pan-SARS-CoV-2 but also varied pan-sarbecovirus activities. Through respiratory administration to mice, monovalent and decameric R14 significantly reduce the lung viral RNAs at low dose and display potent pre- and post-exposure protection. Furthermore, structural studies reveal the neutralizing mechanisms of R14 and S43 and the multiple inhibition effects that the multivalent derivatives exert. Our work demonstrates promising convenient drug candidates via respiratory administration against SARS-CoV-2 infection, which can contribute to containing the COVID-19 pandemic.

Suggestion on further strengthening ultra-low emission standards for PM emission from coal-fired power plants in China.

China has established the largest clean coal-fired power generation system in the world by accomplishing the technological transformation of coal-fired power plants (CFPPs) to achieve ultra-low emission. The potential for further particulate matter (PM) emission reduction to achieve near-zero emission for CFPPs has become a hotspot issue. In this study, PM emission from some ultra-low emission CFPPs adopting advanced air pollutant control technologies in China was reviewed. The results revealed that the average filterable particulate matter (FPM) concentration, measured as the total particulate matter (TPM) according to the current national monitoring standard, was (1.67±0.86) mg/m3, which could fully achieve the ultra-low emission standard for key regions (5 mg/m3), but that achieving the near-zero emission standard was difficult (1 mg/m3). However, the condensable particulate matter (CPM), with an average concentration of (1.06±1.28) mg/m3, was generally ignored during monitoring, which led to about 38.7% underestimation of the TPM. Even considering both FPM and CPM, the TPM emission from current CFPPs would contribute to less than 5% of atmospheric PM2.5 concentrations in the key cities and regions in China. Therefore, further reduction in FPM emission proposed by the near-zero emission plan of CFPPs may have less environmental benefit than emission control of other anthropogenic sources. However, it is suggested that the management of CPM emission should be strengthened, and a national standard for CPM emission monitoring based on the indirect dilution method should be established for CFPPs. Those measurements are helpful for optimal operation of air pollutant control devices and continuously promoting further emission reduction.

SrAgAsS4: A Noncentrosymmetric Sulfide with Good Infrared Nonlinear Optical Performance Induced by Aliovalent Substitution from Centrosymmetric SrGa2S4.

A new noncentrosymmetric (NCS) quaternary sulfide, SrAgAsS4, was obtained via the strategy of aliovalent substitution based on centrosymmetric (CS) SrGa2S4. The new compound features two-dimensional [AgAsS4]2- layers, which are composed of alternately connected [AsS4] tetrahedra and [AgS4] tetrahedra. Importantly, SrAgAsS4 exhibits a strong phase-matched second-harmonic generation response (1.35 × AgGaS2 at 2100 nm) and has a suitable birefringence (0.15@2100 nm) and moderate band gap (2.31 eV). The first-principles calculations revealed the significant contribution of [AsS4] and [AgS4] tetrahedra to its optical properties. This work will promote the application of the aliovalent substitution strategy in the design of NCS-structure-based functional materials.

Multi-cation hybrid stannic oxide electron transport layer for high-efficiency perovskite solar cells.

The performance of perovskite solar cells (PSCs) can be improved by optimizing the perovskite film quality and electron transfer layers (ETLs). In this study, high-efficient PSCs with multi-cation hybrid electron transport layer (SnO2@Na:Cs ETL) were fabricated using continuous spin-coating. Compared to the pristine SnO2, the power conversion efficiency (PCE) of device based on SnO2@Na:Cs ETL have reached 22.06% (with an open circuit voltage of 1.13 V), up approximately 21%. The photovoltaic performance of the device is enhanced due to the increase in the transmission rate, electrical conductivity, electron mobility and surface state owing to the multi-cation hybrid. In addition, because SnO2@Na:Cs ETL can significantly improve interface contact with the perovskite film and improve its crystallinity, the transport defect state and carrier transport efficiency are significantly improved at the ETL/Perovskite interface. Therefore, the open circuit voltage (Voc) and fill factor (FF) of PSCs was significantly increased. The application of SnO2@Na:Cs ETL provides a simple and efficient method to obtain highly-efficient PSCs.

An online technology for effectively monitoring inorganic condensable particulate matter emitted from industrial plants.

The concentration of condensable particulate matter (CPM) has gradually exceeded that of filterable particulate matter emitted from industrial plants equipped with advanced air pollution control systems. However, there is still no available online technology to measure CPM emissions. Based on the significant linear correlations (R2 > 0.87, p < 3 × 10-3) between the electrical conductivity (EC) values and ionic mass concentrations of the CPM solutions when the interference of H+ was excluded. We developed an online inorganic CPM monitoring system, including a cooling and condensation unit, pH and EC meters, a self-cleaning unit, and an automatic control unit. The CPM mass concentrations obtained by the developed online monitoring system agree well (mean bias 3.8-20.7%) with those obtained by the offline system according to USEPA Method 202 when used in parallel during real-world studies. Furthermore, individual ion mass concentrations of CPMs can even be retrieved separately with a time resolution of one hour when industrial plants are under steady operating conditions. The newly developed system makes the online monitoring of CPM emissions available and lays a foundation for the control of CPM emitted from industrial sources to further improve air quality.

Emission characteristics of heavy metals from a typical copper smelting plant.

Heavy metal emissions from non-ferrous smelting plants have been a rising concern. However, their emission characteristics were still unclear. In this study, the concentrations and gas-particle partition of five major heavy metals (Cu, Pb, As, Cr and Cd) in the flue gas from a typical copper smelting plant were measured. The bi-modal distribution of both particulate matter and heavy metals indicated that the particles in super-micron mode was caused by the mechanical crushing and escaping of raw materials, whereas the formation of submicron mode was due to the evaporation and subsequent condensation of volatile substances. The excellent performance of existing air pollution control devices in the studied smelter could substantially reduce the particulate matter and heavy metal concentrations in the extraction and smelting stages by 99.2%-99.9%. The emission factors of PM2.5, Cu, Pb, As, Cr, and Cd were only 283, 2.49, 0.97, 5.92, 0.28, and 0.06 g/t, mostly as the fugitive emission (84.2% on average). In addition, the 'unfilterable' phase of the heavy metals, including the gaseous species and solutes in the filter-penetrated droplet, accounted for averagely 45.8% of the total emissions at the outlet, which indicates the huge underestimation by particle collection only.

High-efficiency planar heterojunction perovskite solar cell produced by using 4-morpholine ethane sulfonic acid sodium salt doped SnO2.

Perovskite solar cells (PSCs) have become a promising photovoltaic (PV) technology. Meanwhile, developing an electron transport layer (ETL) has been an effective way to promote the power conversion efficiency (PCE) of PSCs. Here, a 4-morpholine ethane sulfonic acid sodium salt (MES Na+) doped SnO2 ETL is utilized in planar heterojunction PSCs. The results show that the MES Na+ doped ETL can improve the crystallinity, and absorbance of perovskite films, and passivate interface defects between the perovskite film and SnO2 ETL. The doping effect accounts for the enhancement of conductivity and the decreasing work function of SnO2. When 10 mg mL-1 MES Na+ was added to the SnO2 precursor solution, the device showed the best performance Jsc, Voc, and FF of the PSCs values, which were 23.88 mA cm-2, 1.12 V and 78.69%, respectively, and the PCE was increased from 17.43% to 21.05%. This doping ETL strategy provides an avenue for defect passivation to further increase the efficiency of perovskite solar cells.

[Transmission of Coronavirus via Aerosols and Influence of Environmental Conditions on Its Transmission].

The COVID-19 pandemic has endangered human health and production since 2019. As an emerging disease caused by SARS-CoV-2, its potential transmissibility via aerosols has caused heated debate. This work summarizes the current research findings on virus aerosol generation, aerodynamic properties, and environmental influencing factors on their survivability in order to elucidate coronavirus transmission via aerosols. The occurrence and distinction of SARS-CoV-2, SARS-CoV-1, and MERS-CoV in real atmospheric environments are summarized. The deficiencies of existing research and directions for necessary future research on confirming the airborne transmission mechanism of coronavirus as well as the need for multidisciplinary research are discussed.

Air pollutant emissions from coal-fired power plants in China over the past two decades.

China is the largest coal producer and consumer in the world, and coal-fired power plants are among its major sources of air pollutants. The Chinese government has implemented various stringent measures to reduce air pollutant emissions over the past two decades. National statistical data, emission inventories, and satellite observations indicate that air pollutant emissions from coal-fired power plants have been effectively controlled. Field measurements at coal-fired power plants can provide valuable information about the long-term trend of air pollutant emissions and the driving factors. In this study, we evaluated air pollutant emissions from 401 units at 308 coal-fired power plants. An appreciable reduction in air pollutant concentrations and emission factors from coal-fired power plants in China is observed over the past two decades. The drivers for this trend from the perspective of policy making, application of removal technologies, tightening of emission standards, technological improvement, monitoring systems, and economic measures are discussed. Currently, concentrations of typical air pollutants from coal-fired power plants in China are lower than those in Japan, Germany, and the US. This can be attributed to the policies and lenient emission standards for power plants in these countries. The technological improvement of air pollution control devices is the key factor that has led to reductions in air pollutant emissions in China. China has built the largest system of clean coal-fired power plants in the world.

[Characteristics of Condensable Particulate Matter in Ultra-low Emission Coal-Fired Power Plants].

The condensable particle matter (CPM) from coal-fired power plants has attracted significant attention for its potential influence on air quality. The knowledge of CPM emissions from coal-fired power plants is limited. In this study, CPM was collected at the inlet and outlet of wet flue gas desulfurization (WFGD) and the outlet of wet electrostatic precipitator (WESP) using in-direct dilution method. Both mass concentration and water-soluble ions of CPM were analyzed after sampling. The gas precursors were measured at the same time. We showed that gas precursors such as HCl, HNO3, SO3, and NH3 significantly contributed to CPM from coal-fired power plants. As the temperature of flue gas decreased, these gas precursors were observed to form CPM. The major components of CPM were water-soluble ions such as SO42-, Cl-, NO3-, and NH4+. WFGD and WESP could reduce the CPM gas precursors. Therefore, CPM concentrations after WFGD and WESP of the five tested coal-fired power plants were reduced by 27% and 45%, respectively. In addition, the condensation of SO3 increased SO42- concentration but reduced Cl- and NO3- contents. Finally, SO42- was found to be the major water-soluble ion of CPM.

Transient species in the ozonolysis of tetramethylethene.

The reaction of alkenes with ozone has great effect on atmospheric oxidation, its transient species can produce OH radicals and contribute to the formation of secondary organic aerosols (SOA). In the present study, the reaction of tetramethylethene (TME) with ozone was investigated using self-assembled low temperature matrix isolation system. The TME and ozone were co-deposited on a salt plate at 15 K, and then slowly warmed up the plate. The first transient species primary ozonide (POZ) was detected, indicating that the reaction followed Criegee mechanism. Then POZ began to decompose at 180 K. However, secondary ozonide (SOZ) was not observed according to Criegee mechanism. Probably, Criegee Intermediate (CI) did not react with inert carbonyl of acetone, but with remaining TME formed tetra-methyl epoxide (EPO).

Significant ultrafine particle emissions from residential solid fuel combustion.

When addressing particulate matter (PM) emissions from residential solid fuel combustion, ultrafine particles are usually merged into PM2.5, while whose mass concentration is applied as the index in evaluating PM pollution as well as assessing PM-induced health risk. This may not effectively represent the risk from ultrafine particles. In this study, we explored ultrafine particle emissions during residential combustion under both laboratory-controlled and real-world rural household conditions. Significant ultrafine particle emissions (i.e. with emission factors between 2 × 1015 to 2 × 1016 particles per kg of fuel) are found for both coal and biomass. High emissions of particle mass concentration often occur at the beginning of the combustion (i.e. the first 30 min after fire start) while high emissions of particle number concentration occur in a later combustion period (60-150 min). Ultrafine particles account for over 90% of the emitted total particle number concentration from 3 nm to 10 µm. These emissions elevate ultrafine particle number concentration by more than a decade in indoor environment under which household residents are directly exposed. In addition, we show that there is notable inconsistency between reducing PM2.5 mass based emissions and reducing ultrafine particle number based emissions among various control strategies that were proposed for reducing pollution from residential combustion. Both "cleaner" fuels and stoves that are designed to reduce PM2.5 emissions are found to be not necessarily effective in reducing ultrafine particle emissions, even increase their emissions in some cases. These findings indicate that the overlook of ultrafine particle emissions from residential solid fuel combustion can lead to potential health risk to household residents, especially to those vulnerable ones (e.g., the elderly and children) who are more sensitive to indoor air pollution. More attentions are needed on ultrafine particle pollution and its potential health risk in comparison to using the PM mass concentration index alone.

Evaluating Airborne Condensable Particulate Matter Measurement Methods in Typical Stationary Sources in China.

The dry impinger method, the indirect dilution method, and the direct dilution method can be used to measure the condensable particulate matter (CPM) emissions. We tested these methods in determining the CPM emissions from typical stationary sources in China and found that the CPM concentrations measured by the dry impinger method are much higher than those measured by the two dilution methods regardless of the type of stationary source. The soluble gases (e.g., SO2, HCl, and NH3) partially absorbed by the impinger solutions are the main reason for the overestimation of the CPM concentrations. This is supported by detecting more water-soluble ions (e.g., SO42-, Cl-, and NH4+) from the CPM collected using the dry impinger method. The positive biases of the CPM concentration and its water-soluble ions collected by the dry impinger method are larger under the conditions with high concentrations of soluble gases such as at the flue gas desulfurization inlet in coal-fired power plants. Comparing to the direct dilution method, the indirect dilution method can better capture the rapid dilution, cooling, and condensation of condensable gas precursors in the presence of filterable particulate matter and is recommended as the appropriate method for the CPM measurement in stationary sources.