Field-Tuning Mechanisms of Spin Switching and Spin Reorientation Transition in Praseodymium-Erbium Orthoferrite Single Crystals.

Field-tuning mechanisms of spin switching and spin reorientation (SR) transition were investigated in a series of high-quality single crystal samples of PrxEr1-xFeO3 (x = 0, 0.1, 0.3, 0.5) prepared using the optical floating zone method. The single crystal quality, structure, and axis orientation were determined by room-temperature powder X-ray diffraction, back-reflection Laue X-ray diffraction, and Raman scattering at room temperature. Magnetic measurements indicate that the type and temperature region of SR transition are tuned by introducing different ratios of Pr3+ doping (x = 0, 0.1, 0.3, 0.5). The trigger temperatures of spin switching and magnetization compensation temperature of PrxEr1-xFeO3 crystals can be adjusted by doping with different proportions of Pr3+. Furthermore, the trigger temperature of the two types of spin switching in Pr0.3Er0.7FeO3 along the a-axis can be regulated by an external field. Meanwhile, the isothermal magnetic field-triggered spin switching effect is also observed along the a and c-axes of Pr0.3Er0.7FeO3. An in-depth understanding of the magnetic coupling and competition between the R3+ and Fe3+ magnetic sublattices, within the RFeO3 system, has important implications for advancing the practical applications of the relevant spin switching materials.

Similarities and differences among the responses to three chlorinated organophosphate esters in earthworm: Evidences from biomarkers, transcriptomics and metabolomics.

The wide use of chlorinated organophosphate esters (Cl-OPEs) as additive flame retardants has aroused concern about their potential risks on ecosystem and human health. However, knowledge about the toxicity of Cl-OPEs on soil organisms remains limited. In this study, earthworms, Eisenia fetida, were exposed to three representative Cl-OPEs, i.e., tris(2-chloroethyl) phosphate (TCEP), tris(2-chloro-1-methylethyl) phosphate (TCPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) in artificial soil. Using a combination of biochemical indicators (biomarkers), transcriptomics, and metabolomics, we compared the Cl-OPE-induced toxicity to E. fetida and provide new insight into the related molecular mechanism. All three Cl-OPEs elicited immune defense by the earthworms, as evidenced by increased acid phosphatase and alkaline phosphatase activities, and the genes involved in immune-related pathways (e.g., lysosomal and interleukin-17 signaling pathways). Furthermore, no effects on acetylcholinesterase activity were observed among the three Cl-OPEs. However, the TCPP and TDCPP treatments significantly decreased the neurotransmitter serotonin, suggesting the potential neurotoxicity of Cl-OPEs. Although TCEP affected the genes involved in carbohydrate and amino acid metabolism, the changes in the corresponding metabolites were not statistically significant. In contrast, exposure to TCPP and TDCPP induced oxidative stress, and affected xenobiotic metabolism and energy metabolism, leading to the decreased body weight in E. fetida. Based on these toxic effects, TCPP and TDCPP were more severely toxic than TCEP, despite their structural similarity. Given that the use of TCEP has been tightly regulated, our results suggest the potentially toxic effects of TCPP and TDCPP should not be ignored in future risk assessments of flame retardants.

Capillary-driven blood separation and in-situ electrochemical detection based on 3D conductive gradient hollow fiber membrane.

It is essential to develop portable, versatile, and reliable diagnostic devices in point-of-care testing (POCT). The detection of biomarkers requires selective separation and large specific surface for high sensitivity and accuracy at trace levels in whole blood samples using POCT devices. Herein, a kind of 3D electrochemical biosensors were designed via in-situ synthesizing polyaniline (PANI) and platinum nanoparticles (Pt NPs) on polysulfone hollow fiber membrane (HFM) scaffolds with gradient porous structure. The gradient porous HFMs scaffolds provide uniform capillary flow, self-driven blood separation and sufficient enzyme immobilization sites. Simultaneously, the in-situ deposited materials fulfill interconnected conductive networks, thus ensuring accurate and rapid detection of the sensors without hindering capillary progress. These sensors display ultralow sampling (~3 µL), fast fluid flow (>1 µL/ms), wide linear range (glucose: 0-24 mM, R2=0.992; cholesterol: 0-9 mM, R2=0.999), high sensitivity and accuracy especially under different hematocrits in POCT applications towards glucose and cholesterol. The innovative integration of POCT biosensors with interconnected conductive nanoparticles, selective blood separation and gradient porous structures can find wide application in resource-limited regions, large population screening, and public health emergencies.

Gastroscopic Panoramic View: Application to Automatic Polyps Detection under Gastroscopy.

Endoscopic diagnosis is an important means for gastric polyp detection. In this paper, a panoramic image of gastroscopy is developed, which can display the inner surface of the stomach intuitively and comprehensively. Moreover, the proposed automatic detection solution can help doctors locate the polyps automatically and reduce missed diagnosis. The main contributions of this paper are firstly, a gastroscopic panorama reconstruction method is developed. The reconstruction does not require additional hardware devices and can solve the problem of texture dislocation and illumination imbalance properly; secondly, an end-to-end multiobject detection for gastroscopic panorama is trained based on a deep learning framework. Compared with traditional solutions, the automatic polyp detection system can locate all polyps in the inner wall of the stomach in real time and assist doctors to find the lesions. Thirdly, the system was evaluated in the Affiliated Hospital of Zhejiang University. The results show that the average error of the panorama is less than 2 mm, the accuracy of the polyp detection is 95%, and the recall rate is 99%. In addition, the research roadmap of this paper has guiding significance for endoscopy-assisted detection of other human soft cavities.

Taste and odor compounds associated with aquatic plants in Taihu Lake: distribution and producing potential.

The odor problem caused by the decay of aquatic plants is widespread in many freshwater lakes. In this study, the spatial distributions of seven taste and odor (T&O) compounds (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 2-methylisoborneol, geosmin, ß-cyclocitral, and ß-ionone) in the sediments and overlying water of the east of Taihu Lake were investigated. The effects of plant and physico-chemical parameters on the release of T&O compounds were also analyzed. The results showed that high concentrations of T&O compounds were detected in the area where Eichhornia crassipes was flourishing. Volatile organic sulfur compounds were not found in the water source area, which was not covered by aquatic plants. High plant biomass and aquiculture activities might increase the release of the taste and odor compounds. The correlation between the concentrations of odorous compounds and nutrients in the sediment was also analyzed. The production of odorants was positively correlated with the nitrogen, and they may migrate from sediment to overlying water. The result suggested that controlling the plant density and aquaculture activities could reduce the release of odorous compounds.

Ecotoxicological effects and accumulation of ciprofloxacin in Eichhornia crassipes under hydroponic conditions.

Antibiotic residues pose a threat to the health of aquatic organisms. The effects and accumulation of antibiotic ciprofloxacin (CIP) in a floating macrophyte (Eichhornia crassipes) under hydroponic conditions were investigated. It was found that E. crassipes exposure to CIP (< 1000 µg L-1) could maintain a stable photosynthesis efficiency. In response to CIP stress, catalase and peroxidase activities of leaves were 7.24-37.51 nmol min-1 g-1 and 98.46-173.16 U g-1, respectively. The presence of CIP did not inhibit the growth of the plant. After 14 days of exposure, tender leaves became white and withered, ascribed to the decline of chlorophyll content and chlorophyll fluorescence parameters. The CIP concentrations, absorbed by E. crassipes, were highest in the roots, followed by white aerial parts and green aerial parts at CIP concentrations of 100 and 1000 µg L-1. These findings demonstrated that E. crassipes could absorb and tolerate CIP in a limited time-scale and imply an alternative solution for phytoremediation in water bodies contaminated with antibiotics.

Release of taste and odour compounds during Zizania latifolia decay: A microcosm system study.

Organic matter-induced black bloom frequently occurs in a number of large eutrophic shallow lakes; this can result in the release of malodorous compounds and has a negative impact on water quality. In the study, a microcosm system containing Zizania latifolia (Z. latifolia), a common aquatic plant, was established and the release of seven taste and odour compounds, dimethyl sulphide (DMS), dimethyl disulphide (DMDS), dimethyl trisulphide (DMTS), 2-methylisoborneol (MIB), geosmin (GSM), ß-cyclocitral, and ß-ionone, was investigated. The results showed that these compounds were all detected during Z. latifolia decay, and that volatile organic sulphur compounds (VOSCs), such as DMS, DMDS, and DMTS, were the main factors responsible for the strong foul odour (the maximum reached 5.0 µg L-1). The release of odorous compounds was stronger during the initial seven days, and then progressively decreased in the middle stage of the experiment. Furthermore, large amounts of nutrients were released into the overlying water; nutrient concentration increased with increasing plant biomass. A positive correlation was observed between the odorant concentration and plant biomass. These results indicate that the density of aquatic plants should be controlled as part of future management of aquatic ecosystems.

Response of Taste and Odor Compounds to Elevated Cyanobacteria Biomass and Temperature.

Taste and odor (T&O) compounds are frequently reported during black blooms, however, their production mechanisms and influencing factors are far from clear. In this study, laboratory simulation experiment was carried out to investigate the formation processes of T&O compounds under the influences of temperature, cyanobacteria biomass and their combined effects. The decay of cyanobacteria blooms caused increased T&O compounds loading to water. Results showed the maximum dimethyl sulfide (DMS) release concentration was observed at 35°C compared with that at 25 and 30°C. DMS release concentration under cyanobacteria biomass of 25000 g/m3 demonstrated the highest production, whereas the minimum DMS production were obtained under 7500 g/m3. Similar patterns were observed for dimethyl disulfide, dimethyl trisulfide, ß-cyclocitral and ß-ionone production. Therefore, higher temperature and higher cyanobacteria biomass can enhance the concentration of T&O compounds. Furthermore, there were synergistic effects of cyanobacteria biomass and temperature on the production of T&O compounds.

Spatial distributions of ß-cyclocitral and ß-ionone in the sediment and overlying water of the west shore of Taihu Lake.

After large-scale outbreaks of algal blooms in eutrophic water, considerable amounts of algae residue accumulate in near-shore zones before fermenting rapidly and becoming malodorous. Taste and odor pollution caused by secondary metabolites from cyanobacterial blooms has become a serious and widespread environmental problem. Two typical odorous compounds, ß-cyclocitral and ß-ionone, have gained increasing attention in recent years. In this paper, the spatial distributions of ß-cyclocitral and ß-ionone in the sediments and overlying water off the west shore of Taihu Lake were investigated. The results showed that ß-cyclocitral, ß-ionone and nutrients are released during the degradation of fresh cyanobacteria, especially in the early stages. The odorous compounds and nutrients greatly decreased as the depth of sediment increased, indicating that reed roots can absorb ß-cyclocitral, ß-ionone and nutrients. Furthermore, removing cyanobacteria and dredging sludge might reduce the release of ß-cyclocitral and ß-ionone.