Multishell Silver Indium Selenide-Based Quantum Dots and Their Poly(methyl methacrylate) Composites for Application in Red-Light-Emitting Diodes.

In this work, the production of novel multishell silver indium selenide quantum dots (QDs) shelled with zinc selenide and zinc sulfide through a multistep synthesis precisely designed to develop high-quality red-emitting QDs is explored. The formation of the multishell nanoheterostructure significantly improves the photoluminescence quantum yield of the nanocrystals from 3% observed for the silver indium selenide core to 27 and 46% after the deposition of the zinc selenide and zinc sulfide layers, respectively. Moreover, the incorporation of the multishelled QDs in a poly(methyl methacrylate) (PMMA) matrix via in situ radical polymerization is investigated, and the role of thiol ligand passivation is proven to be fundamental for the stabilization of the QDs during the polymerization step, preventing their decomposition and the relative luminescence quenching. In particular, the role of interface chemistry is investigated by considering both surface passivation by inorganic zinc chalcogenide layers, which allows us to improve the optical properties, and organic thiol ligand passivation, which is fundamental to ensuring the chemical stability of the nanocrystals during in situ radical polymerization. In this way, it is possible to produce silver-indium selenide QD-PMMA composites that exhibit bright red luminescence and high transparency, making them promising for potential applications in photonics. Finally, it is demonstrated that the new silver indium selenide QD-PMMA composites can serve as an efficient color conversion layer for the production of red light-emitting diodes.

Minimizing the Anticodon-Recognized Loop of Methanococcus jannaschii Tyrosyl-tRNA Synthetase to Improve the Efficiency of Incorporating Noncanonical Amino Acids.

In the field of genetic code expansion (GCE), improvements in the efficiency of noncanonical amino acid (ncAA) incorporation have received continuous attention. By analyzing the reported gene sequences of giant virus species, we noticed some sequence differences at the tRNA binding interface. On the basis of the structural and activity differences between Methanococcus jannaschii Tyrosyl-tRNA Synthetase (MjTyrRS) and mimivirus Tyrosyl-tRNA Synthetase (MVTyrRS), we found that the size of the anticodon-recognized loop of MjTyrRS influences its suppression activity regarding triplet and specific quadruplet codons. Therefore, three MjTyrRS mutants with loop minimization were designed. The suppression of wild-type MjTyrRS loop-minimized mutants increased by 1.8-4.3-fold, and the MjTyrRS variants enhanced the activity of the incorporation of ncAAs by 15-150% through loop minimization. In addition, for specific quadruplet codons, the loop minimization of MjTyrRS also improves the suppression efficiency. These results suggest that loop minimization of MjTyrRS may provide a general strategy for the efficient synthesis of ncAAs-containing proteins.

ILSHIP: An interpretable and predictive model for hypothyroidism.

Hypothyroidism is one of the common endocrine diseases, and its incidence is increasing year by year. Due to the insidious nature of this disease, it often leads to delayed treatment and even misdiagnosis. This paper proposes ILSHIP, an interpretable predictive model for hypothyroidism, to reduce its diagnostic complexity as well as improve the predictive performance and interpretability of existing models. First, the ILSHIP prediction model was built based on label encoding, missing value processing, feature selection, and data enhancement of the dataset. Second, the comprehensive performance of ILSHIP was compared with twelve existing related study models and eleven mainstream models, such as XGBoost and MLP. The experimental results showed that, based on the optimal hyperparameters the ILSHIP model can achieve 99.392%, 99.437%, 99.348%, 99.381%, and 99.960% in accuracy, recall, specificity, F1, and AUC, respectively. The accuracy of the ILSHIP model was about 0.7%-15.4% higher than the existing models. By introducing the SHAP framework into the ILSHIP model, important features affecting hypothyroidism such as thyroid stimulating hormone (TSH) and free thyroxine index (FTI) were also identified, and the influencing factors for different individuals were finally analyzed to provide a basis for medical personnel to monitor the condition.

Use of sponge iron dosing in baffled subsurface-flow constructed wetlands for treatment of wastewater treatment plant effluents during autumn and winter.

Sponge iron (SI) is widely used in water treatment. As effluents from wastewater treatment plant (WWTP) require advanced treatment methodology, three forms of constructed wetlands (CWs): wetlands with sponge iron (SI), copper sulfate modified sponge iron (Cu/SI), and sponge iron coupled with solid carbon sources (C/SI), have been investigated in this paper for the removal effects of organic matter and nutrients in WWTP effluents, and the corresponding mechanisms have been analyzed. The results showed the effect of baffled subsurface-flow constructed wetland (BSFCW) with SI dosing to purify the WWTP effluents after the stable operation. The water flow of this BSFCW is the repeated combination of upward flow and downward flow, which can provide a longer treatment pathway and microbial exposure time. The average removal rates of total inorganic nitrogen (TIN) were 27.80%, 30.17%, and 44.83%, and the average removal rates of chemical oxygen demand (COD) were 19.96%, 23.73%, and 18.38%. The average removal rates of total phosphorus (TP) were 85.94%, 82.14%, and 83.95%. Cu/SI improved the dissolution of iron, C/SI improved denitrification, and a winter indoor temperature retention measure was adopted to increase the effectiveness of wetland treatment during the winter months. After comprehensively analyzing X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and two-dimensional numerical simulation diagrams, a plausible conjecture that microbes use electrons from SI for autotrophic denitrification is presented. Moreover, the stress effect of wetlands dosed with SI on plants decreased stepwise along the course since C/SI used on wetlands had less impact on plant stress.

1. Treatment of sequencing batch biofilm reactor reaction effluent indoors in low temperature using a combination of three wetland fillers, sponge iron + gravel, copper sulfate modified sponge iron + gravel, and sponge iron coupled carbon source + gravel.2. The use of the baffled subsurface-flow constructed wetland, combined with the distribution simulation diagram, especially the distribution simulation diagram of iron, gives an explanation to the degradation mechanism of the pollutants and the transformation of iron into wetlands.3. An conjecture of electron transport during microbial autotrophic denitrification involving iron is presented, plausibly explaining the variation in treatment effects.

A molecularly imprinted chitosan doped with carbon quantum dots for fluorometric determination of perfluorooctane sulfonate.

A molecularly imprinted polymer (MIP) was fabricated for selective recognition of the highly persistent pollutant perfluorooctane sulfonate (PFOS). The MIP was prepared from chitosan and doped with fluorescent carbon quantum dots (CQDs). It was characterized by fluorescence spectrophotometry, scanning electron microscopy, and Fourier transform infrared spectroscopy. The fluorescence of the CQDs, best measured at excitation/emission wavelengths of 350/460 nm, is enhanced by PFOS, and the effect is much stronger for the MIP than for the nonimprinted polymer (NIP). The imprinting factor is 2.75. The method has good specificity over sodium dodecyl sulfate (SDS), perfluorooctanoic acid (PFOA), sodium dodecyl sulfonate (SDS'), sodium dodecyl benzene sulfonate (SDBS), perfluorooctanesulfonyl fluoride (POSF), perfluorobutane sulfonate (PFBS) and 1-octanesulfonic acid sodium (OSA). Fluorescence increases linearly in the 20-200 pg·L-1 POSF concentration range in aqueous solution. The method was applied to the determination of PFOS in spiked serum and urine samples. The limits of detection are 66 and 85 pg·L-1 for serum and urine samples respectively. The recoveries ranged from to 81-98%, with relative standard deviations in the range of 1.8-8.2%. Compared with LC-MS/MS, this assay is more convenient since the material can be prepared flexibly and the method can be applied on-site. Graphical abstract Schematic of the fabrication of a molecularly imprinted chitosan hydrogel doped with CQDs for selective fluorometric determination of PFOS. a. The photo of chitosan hydrogel. b, c, d, e represents the hydrogel observed under UV lamp. b', c', d', e' represents the inner structure of hydrogel bead.

[Distribution Characteristics and Risk Assessment of Phthalic Acid Esters in Agricultural Products Around the Pearl River Delta. South China].

In order to investigate and assess the distribution of pathalic acid easters (PAEs) in agricultural products from typical areas of the Pearl River Delta, South China, 131 agricultural products were sampled for determination of 6 PAEs priority pollutants classified by the U. S. EPA by GC-FID. The results showed that the total contents of the PAEs (sigma PAEs) in agricultural products samples ranged from nd to 79.86 mg x kg(-1) and the mean value was 2.84 mg x kg(-1), with the detected ratio of 98.5%. The average concentrations of sigma PAEs in different types of agricultural products were ordered by vegetables (3.03 mg x kg(-1)) > rice (2.52 mg x kg(-1)) > fruits (1.26 mg x kg(-1)). The mean concentration of PAEs distributed in the four typical cities of the Pearl River Delta, and decreased in the sequence of Zhuhai (6.53 mg x kg(-1)) > Dongguan (2.59 mg x kg(-1)) > Huizhou (1.53 mg x kg(-1)) > Zhongshan (1.12 mg x kg(-1)). Di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) contributed more than 90. 8% of the total PAEs in samples, and were the main components of PAEs in agricultural products from the Pearl River Delta, with higher percentage contents and detected ratio. Meanwhile, the average concentrations of sigma PAEs in cabbage mustard, lettuce occurred in Zhuhai and Dongguan cities, followed by lettuce and leaf lettuce in the corresponding DEHP from Zhuhai city, both exceeded the suggested standards in U.S.A. and Europe and were of high health risk. There were significant differences among 14 various vegetables in the contents of the 6 PAEs compounds, and the sigma PAEs contents in cabbage mustard and lettuce as part of leafy vegetables were higher than those in other vegetables, while the lowest were detected in flowering cabbage and edible amaranth. Therefore, the type of vegetables and its growing environment exposed to the atmosphere and soil were the main factors that significantly affected their accumulation of PAEs concentrations.

[Characteristics of Phthalic Acid Esters in Agricultural Soils and Products in Areas of Zhongshan City, South China].

In order to investigate and assess the pollution level of phthalic acid esters (PAEs) in farm soils and products from typical agricultural fields in areas of Zhongshan City, Guangdong Province, South China, 65 topsoil and 37 agricultural product samples were collected and contents of 6 PAEs compounds that classified by the U. S. Environmental Protection Agency (EPA) as priority pollutants were determined by the GC-FID. The results indicated that total contents of the PAEs (∑ PAEs) in soils ranged from 0. 14 to 1. 14 mg x kg(-1), and the mean value was 0.43 mg x kg(-1), with the detected ratio of 100%. Various concentrations of PAEs differed in three land-use types were ordered by vegetable soil > orchard soil > paddy soil. Comparing with six U.S. EPA priority pollutants of PAEs, the contents of Di-n-butyl phthalate (DBP) and Dimethyl phthalate ( DMP) in soils exceeded the control limits of PAEs in the American soil by 93.85% and 27.69% respectively, but the rest four PAEs compounds were lower than the control limits. Generally, the pollution level of soils contaminated by PAEs in agricultural fields of Zhongshan City was relatively low. The contents of 3 PAEs in agricultural products ranged from 0.15 to 3.15 mg x kg(-1) with the average of 1.12 mg x kg(-1), which was lower than the suggested standards in USA and Europe and with low health risk. Meanwhile, ∑ PAEs concentrations in vegetables were higher than those both in rice and fruits. DBP and DEHP were the main components of PAEs both in agricultural soils and products, with higher percentage contents and detected ratio. ∑ PAEs and DBP contents in various agricultural products-soils had a significantly positive correlation, with Pearson coefficients (r) in vegetables-vegetable soils were 0.81 (P = 0.000), 0.75 (P = 0.000), and corresponding r among rice-paddy soil and fruits-fruit soils were 0.74 (P = 0.036), 0.65 (P = 0.041) and 0.66 (P = 0.029), 0.78 (P = 0.045), respectively. Although there existed a significant difference for single PAEs compound accumulated by agricultural products, the ∑ PAEs bioconcentration factors of all agricultural products were above 1. Therefore, the accumulation characteristics of PAEs should be fully concerned when farm soil quality assessment is taken.

[Determination of sperm DNA integrity by improved sperm chromatin structure assay test].

OBJECTIVE: To search for a simple, quick and accurate method for the sperm DNA integrity test by modifying the conventional sperm chromatin dispersion (SCD) test, and to investigate the reference value range of normal sperm DNA integrity by the improved SCD assay. METHODS: We modified the conventional SCD test in its procedures, reagents preparing and utensils to be used, compared the improved method with the conventional one, and detected 293 normal semen samples for sperm DNA integrity by the modified SCD test. RESULTS: An improved SCD test was established, and no statistical differences were found between the results of the modified and conventional methods. The reference value range was determined by the improved SCD assay for normal sperm DNA integrity, which was < 32.58% for abnormal sperm DNA integrity. CONCLUSION: The improved SCD test could detect sperm DNA integrity more quickly, and it reduced the cost in reagents.