Distribution, sedimentary record, and persistence of microplastics in the Pearl River catchment, China

Microplastics (MPs) in the environment have become an issue worldwide. However, data about MPs in freshwater systems are still limited so far. This study investigated sources, fate, and seasonal and spatial distribution of MPs in the main stream Pearl River and its tributaries, as well as in the Pearl River Estuary (PRE), China. MPs were widely detected in the river water, river bed sediment, and estuarine sediment, with abundances of 0.57 +/- 0.71 items L-1, 685 +/- 342 items kg(-1) dry weight (dw), and 258 +/- 133 items kg(-1) dw, respectively. Sheet, fragmental, and fibrous polyethylene, polypropylene, and ethylene-propylene copolymers were predominant, suggesting that MPs in the Pearl River catchment be mainly derived from fragmentation of discarded plastic wastes. In addition, municipal wastewater was also an important MPs source, especially for polyethylene terephthalate (PET) fibers. Polymers of higher density, such as PET and polyvinyl alcohol were relatively more abundant in the sediment than in the river water, especially in the estuarine sediment. Upward increase of the MP abundance was observed in the sedimentary core, probably indicating increasing release of plastic wastes due to growing production and uses of plastic products. On the other hand, percentage of finer MPs increased with increasing depth. The results revealed persistence and potential downward dispersion of the fine MPs. The MPs abundance was positively related with population density and gross domestic product, demonstrating impacts of human activities and economic development on the MPs contamination. Higher MPs abundance was detected in dry season than in wet season in the river water, suggesting dilution effect of precipitation. It's estimated that 15963 tons of MPs could be released annually into the PRE from the main stream Pearl River and its tributaries. (C) 2019 Elsevier Ltd. All rights reserved

Tissue Distribution, Growth Dilution, and Species-Specific Bioaccumulation of Organic Ultraviolet Absorbents in Wildlife Freshwater Fish in the Pearl River Catchment, China

Tissue distributions and body-size dependent and species-specific bioaccumulation of 12 organic ultraviolet absorbents (UVAs) were investigated in 9 species of wildlife freshwater fish from the Pearl River catchment, South China. The concentrations of the 12 UVAs were from 109 to 2320 ng/g lipid weight in the fish tissue samples. The UVAs 2-hydroxy-4-methoxybenzophenone (BP-3), octocrylene (OCR), UV531, and 5 benzotriazole UV stabilizers (UVP, UV329, UV234, UV328, and UV327) were detected in more than half of the fish tissue samples. The UVA UV531 showed an obvious potential for bioaccumulation in the wild freshwater fish, with an estimated bioaccumulation factor (log BAF) and a biota-sediment accumulation factor (BSAF) of 4.54 +/- 0.55 and 4.88 +/- 6.78, respectively. Generally, liver (989 +/- 464 ng/g lipid wt) contained the highest level of UVAs, followed in decreasing order by belly fat (599 +/- 318 ng/g lipid wt), swimming bladder (494 +/- 282 ng/g lipid wt), dorsal muscle (470 +/- 240 ng/g lipid wt), and egg (442 +/- 238 ng/g lipid wt). The bioaccumulation of UVAs in the freshwater wild fish was species specific and compound dependent. Bottom-dwelling detritus-ingesting omnivorous fish contained obviously higher UVA concentrations, suggesting that detritus/sediment ingestion is a significant pathway for exposure of the wild freshwater fish to the UVAs. The UVAs UV531 and BP-3 demonstrated a potential for growth dilution. Metabolism might play a significant role in elimination of the UVAs in the fish tissues, with the highest rate of metabolism in the liver. The UVAs did not demonstrate obvious trophic magnification in the freshwater ecosystem of the Pearl River catchment. More research is warranted to elucidate maternal transfer of the UVAs. Environ Toxicol Chem 2020;39:343-351. (c) 2019 SETA

Occurrence and Species-Specific Distribution of Plastic Debris in Wild Freshwater Fish from the Pearl River Catchment, China

Freshwater systems are an important source and vector of plastic debris found in oceans. However, plastic debris in freshwater organisms has not been well studied. The occurrence, characterization, polymer composition, and seasonal and spatial distribution of plastic debris were investigated in 9 species of wild freshwater fish from the Pearl River catchment, south China. Approximately 50% of the total fish (n = 279) belonging to 9 species were found to ingest plastic debris with an average abundance of 7.0 +/- 23.8 items/individual, indicating wide plastic contamination in the Pearl River catchment. Plastic debris were predominantly transparent or white in color, fibers or fragments in shape, and polyethylene, polypropylene, ethylene-propylene copolymer (PE-PP), and polyethylene terephthalate (PET) in polymer composition. A species-specific distribution of the plastic debris was observed in terms of abundance, shape, and polymer composition. Redbelly tilapia had the highest (27.4 +/- 54.0 items/individual), whereas common carp had the lowest (0.2 +/- 0.4 items/individual) abundance of the plastic debris in their gastrointestinal tracts. Fibers of PET were predominant in the freshwater species except in barbel chubs, which had mostly PE-PP fragments. Omnivores and bottom-dwellers were more likely to ingest plastic debris. Seasonal variation was observed, with generally higher abundance of plastic debris in fish collected in the dry season than in the wet season. Environ Toxicol Chem 2019;38:1504-1513. (c) 2019 SETA

Fabrication and Characterization of Ni60A Alloy Coating on Copper Pipe by Plasma Cladding with Induction Heating

Plasma cladding coupled induction heating was developed and successfully used to fabricate Ni60A coating on the surface of copper pipe. By matching the swing arc with the rotating copper pipe, the cladding efficiency was as high as 32.72 mm2/s. From the head to the tail of the coating, the wear resistance changed from 4.5 to 1.8 times that of pure copper. During the cladding process with constant current, the surface temperature of the cladding zone and the bath depth gradually increased. The corresponding dilution ratio increased, accompanied by the widening of the interface transition zone and the growth of precipitated phases (CrB and Cr23C6). Due to the gradient change of composition, the coating can be regarded as an in situ synthesized gradient coating. The critical point of sudden change of temperature in cladding zone was 850 °C, at which point the wear mechanism changed from abrasive wear to adhesive wear. The proper surface temperature of cladding zone should be controlled within 600–850 °C, which can be achieved by matching the cladding current and induction heating power. Results indicated that plasma cladding coupled induction heating is a potentially effective method to prepare high-quality coating on the surface of a large-complex-curved copper component

Catalytic calcium-looping reforming of biogas: A novel strategy to produce syngas with improved H2/CO molar ratios

Anaerobic digestion to acquire biogas is currently the most widely used approach to dispose of vast anthropogenic biowastes. However, effective strategies, except for power generation in the energy sector, to utilize the waste-derived biogas resource are lacking. Herein, we propose a new thermochemical biogas transformation process, catalytic calcium-looping reforming of biogas, to produce syngas with a controllable molar ratio of H to CO. In this process, the conventional CH dry reforming reaction is decoupled into the separate CH dissociation reaction to acquire H and reverse Boudouard reaction to acquire CO, respectively. Results showed that the proposed process was able to produce a H-rich stream at a yield of 175.4mmol/g with a H/CO molar ratio of 5.6 at 700 °C, followed by a high-purity CO stream at a yield of 155.4 mmol/g at 800 °C in one biogas reforming cycle. It is shown that the reaction between CO and the carbon species with a graphitic ordering is the rate-determining step of the proposed biogas reforming process. Despite the scope for improvement of process stability, the proposed catalytic calcium-looping reforming of biogas has been experimentally demonstrated to be a promising strategy to inherently control the molar ratio of H to CO during syngas production

HCG supplement did not accelerate tunica albuginea remodeling to facilitate penile growth

Abstract Penile size is closely concerned and short penis contributes serious sexual dysfunction and tremendous psychological problems to couples. Androgen is essential for penile development and testosterone replacement is recommended to patients with micropenis. We previously proved that inhibiting activity of lysyl oxidase (Anti-lysyl oxidase, Anti-LOX) combined with vacuum erectile device (VED) lengthened penis by remodeling tunica albuginea. We thus explored whether HCG supplement could accelerate tunica albuginea remodeling (induced by Anti-LOX + VED) to promote penile growth. Forty-two SD male rats (4 weeks old) were purchased and divided into 7 groups: control, Anti-LOX, HCG, VED (with a negative aspirated pressure of − 300 mmHg), Anti-LOX + VED, HCG + VED, and Anti-LOX + HCG + VED. After an intervention for 4 weeks, all rats’ penile length, exposed penile length, and erectile function were measured. Serum samples were collected to detect hormone levels and penile corpus cavernosum were harvested for histo-pathological analysis. All intervention groups showed significantly longer penis than controlled rats. Anti-LOX sharply increased penile length and exposed length by 15% and 9% respectively, this lengthening effect was more obvious in Anti-LOX + VED group (26% and 19%, respectively). Although HCG promoted penile length by 8%, this effect was slight for exposed length (3%). Moreover, Anti-LOX + HCG + VED dramatically increased penile length and exposed length by 22% and 18%, respectively, which was similar with that in Anti-LOX + VED (26% and 19%, respectively). HCG dramatically stimulated testosterone and dihydrotestosterone secretions than control group, whether with or without Anti-LOX and VED; while it induced more AR expression than other groups. Finally, all procedures did not improve or deteriorate normal erectile function. Although we verified that Anti-LOX + VED lengthened penis by inducing tunica albuginea remodeling, however, HCG supplement did not synergize with Anti-LOX + VED to accelerate albuginea remodeling to facilitate penile growth

Anaerobic Ammonium Oxidation in Acidic Red Soils

Anaerobic ammonium oxidation (anammox) has been proven to be an important nitrogen removal process in terrestrial ecosystems, particularly paddy soils. However, the contribution of anammox in acidic red soils to nitrogen loss has not been well-documented to date. Here, we investigated the activity, abundance, and distribution of anammox bacteria in red soils collected from nine provinces of Southern China. High-throughput sequencing analysis showed that Candidatus Brocadia dominates the anammox bacterial community (93.03% of sequence reads). Quantification of the hydrazine synthase gene (hzsB) and anammox 16S rRNA gene indicated that the abundance of anammox bacteria ranged from 6.20 × 106 to 1.81 × 109 and 4.81 × 106 to 4.54 × 108 copies per gram of dry weight, respectively. Contributions to nitrogen removal by anammox were measured by a 15N isotope-pairing assay. Anammox rates in red soil ranged from 0.01 to 0.59 nmol N g−1 h−1, contributing 16.67–53.27% to N2 production in the studied area, and the total amount of removed nitrogen by anammox was estimated at 2.33 Tg N per year in the natural red soils of southern China. Pearson correlation analyses revealed that the distribution of anammox bacteria significantly correlated with the concentration of nitrate and pH, whereas the abundance and activity of anammox bacteria were significantly influenced by the nitrate and total nitrogen concentrations. Our findings demonstrate that Candidatus Brocadia dominates anammox bacterial communities in acidic red soils and plays an important role in nitrogen loss of the red soil in Southern China

A simple method to tune graphene growth between monolayer and bilayer

Selective growth of either monolayer or bilayer graphene is of great importance. We developed a method to readily tune large area graphene growth from complete monolayer to complete bilayer. In an ambient pressure chemical vapor deposition process, we used the sample temperature at which to start the H2 flow as the control parameter and realized the change from monolayer to bilayer growth of graphene on Cu foil. When the H2 starting temperature was above 700°C, continuous monolayer graphene films were obtained. When the H2 starting temperature was below 350°C, continuous bilayer films were obtained. Detailed characterization of the samples treated under various conditions revealed that heating without the H2 flow caused Cu oxidation. The more the Cu substrate oxidized, the less graphene bilayer could form

Pegylated liposomal doxorubicin in patients with epithelial ovarian cancer

Abstract Objective To evaluate the efficacy and safety of PLD in treating of in patients who experience epithelial ovarian, fallopian tubal, and peritoneal cancer progression within 12 months after the first-line platinum-based therapy. Methods This was an open-label, single-arm and multicenter clinical trial. The ORR was the interim primary objective, and the DCR, AEs and QOL were the secondary objectives. The impact of factors on efficacy outcomes, the change trend of CA125 and the artificial platinum-free interval were exploratory endpoints. Results Totally, 115 patients were enrolled in this study and included in the ITT population. Moreover, 101 patients were included in the safety population. The median follow-up time was 4 months (IQR 2–6). In the ITT population, the confirmed ORR was 37.4% (95% CI, 28.4–46.4%), and the DCR was 65.2% (95% CI, 56.4–74.1%). The previous response status to platinum-based chemotherapy and baseline CA125 levels were significantly correlated with the ORR. The ORR was significantly higher in patients with a CA125 decrease after the first cycle than in the patients with a CA125 increase. The most common grade 3 or higher AE was hand-foot syndrome (3 [3.0%] of 101 patients). No statistically significant differences existed between the baseline and the postbaseline questionnaires. Conclusions For patients who experience platinum-resistant and platinum-refractory relapse, the use of PLD may be acceptable because of the associated satisfactory efficacy, low frequency of AEs and high patient QOL. Moreover, a low CA125 level at baseline and a reduction in CA125 after the first cycle are predictive factors for satisfactory efficacy