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Ternary I-III-VI quantum dots, unlike traditional binary counterparts, offer advantages like low toxicity, cadmium-free composition, tunable electronic properties, and near-infrared light emission, making them increasingly popular for their cost-effectiveness and versatile applications in light emission. In this study, monodispersive, water-soluble, highly emissive CuInS2@ZnS quantum dots were synthesized using cysteine and threonine as ligands by a simple one-pot solution method. By adjusting, the ratio of cysteine to threonine to 1:5 and the heating time during the synthesis process to 40 min, CuInS2@ZnS quantum dots achieved the highest fluorescence intensity. Then, CuInS2@ZnS quantum dots were applied for ciprofloxacin (CIP) detection in food sample, showing a linear range of 2–18 μg/ml and a lowest detection limit of 0.28 μg/ml. The fluorescent probe was successfully established by quenching process as CIP concentration increasing, due to photoinduced electron transfer. Experimental results demonstrated the detection method has high sensitivity and good selectivity. We, then utilized smartphones to visually distinguish CIP concentrations based on the colors emitted by the CuInS2@ZnS quantum dots under UV light. The method was finally effectively to detect residual CIP in porcine kidneys, with recoveries of 92%–98%. This approach has promising potential for enhancing food safety testing. [ABSTRACT FROM AUTHOR]

The combination of flotation and chemical oxidation is suitable for extracting black carbon (BC) from the soil around coal-fired power plant. In present study, the content of BC was determined by loss on ignition (LOI) method and potassium dichromate volumetric (PDV) method. Four extraction methods of BC were compared and the extracted BC was characterized by XRD, FTIR, SEM, and XPS. The findings reveal that the BC content obtained through the three chemical oxidation methods ranges from 14.51 to 22.25 g·kg-1, 13.10 to 19.28 g·kg-1, and 19.75 to 35.79 g·kg-1, respectively. The BC content obtained by combining flotation and chemical oxidation ranges from 44.04 to 50.60 g·kg-1, indicating that the combination method is more convenient for BC extraction from soil. The BC content measured by the LOI method is higher. The mineral compositions of fly ash from Kanshan power plant (KFA), BC, and soil minerals are similar and main minerals are quartz, magnetite, and hematite. The surface of both KFA and BC mainly comprises elements such as C, O, N, and Si. These results shows that the BC in the soil maybe originate from fly ash of the power plant. It is of great significance for environmental monitoring and pollution control around coal-fired power plants. [ABSTRACT FROM AUTHOR]

The co-pelletization of microalgae with filamentous fungi was a promising approach for microalgae harvest. However, the real conditions of microalgae growth limited the arbitrary optimization of co-pellets formation with filamentous fungi. Therefore, it is urgent to develop an approach to manipulate the co-pelletization through treatment of A. niger spores. In this study, Aspergillus niger and Chlorella vulgaris were used as the model species of filamentous fungi and microalgae to investigate co-pellets formation using A. niger spores after by different pH solutions treatment, swelling, snailase treatment. The importance of spore treatments on C. vulgaris harvest in sequence was claimed based on response surface methodology analysis. The pH solutions treatment, swelling, snailase treatment of A. niger spore contributed 21.0%, 10.5%, 40.7% of harvest ratio of C. vulgaris respectively, which guided the application of spore treatment into co-pelletization. Treatment of spore was showed as an efficient approach to manipulate co-pelletization for microalgae harvest in diverse microalgae condition. This results promoted the application of co-pelletization technology in microalgae harvest of various conditions. [ABSTRACT FROM AUTHOR]

Extensively employed antibiotics in livestock cause residue in food products that would threaten public health safety. In this work, we have developed a flexible, sensitive, cost-effective graphene oxide (GO)/silver–polyester fibrous membrane (PFM) flexible SERS substrate (GO–Ag–PFM) which is suitable for in situ food safety detection. PFMs built nanoporous networks as a flexible template, while GO–Ag nanomaterials were precipitated on the crossed fibers by self-assembly techniques, providing a density "hot-spot" that significantly increased electromagnetic fields. The lowest distinguishable level of rhodamine 6G is 10−9 mol/L, and the flexible SERS substrates also exhibit good uniformity and reproducibility. The sensitive GO–Ag–PFM flexible SERS substrates achieve low-level SERS detection of florfenicol (FF). The estimated LOD is low to 2.46 × 10−9 mol/L for FF. The proposed method can be applied to the determination of FF residues in milk. The recoveries were 89–98% with a relative standard deviation of 4.5–9.1%, which is expected to show great potential in food safety testing. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present work was to develop a methanol-independent Komagataella phaffii (K. phaffii) strain using a non-methanol promoter. Results: In this study, the food grade enzyme xylanase from Aspergillus niger ATCC 1015 was used as the reporter protein, a recombinant K. phaffii containing a cascade gene circus was designed and constructed using sorbitol as inducer. Sorbitol induced PSDH leading to MIT1 expression firstly, and heterologous protein xylanase expression finally. This system showed 1.7 fold of xylanase activity at the condition of single copy number of extra MIT1, and 2.1 fold of xylanase activity at condition of multi-copy extra MIT1 gene. Conclusions: This sorbitol-induced expression system of K. phaffii avoided toxic and explosive methanol. It was a novel cascade gene expression and a food safety system. [ABSTRACT FROM AUTHOR]

Komagataellaphaffii (syn. Pichia pastoris), a methylotrophic yeast, has many advantages as a protein expression system, but has the disadvantage of hazardous methanol as an inducer and carbon source. To enable substitution of formate for methanol, a formate assimilation pathway was constructed by the co-expression of acetyl-CoA synthase, acetaldehyde dehydrogenase, and transcription factor Mit1, resulting in a 103.5 ± 12.5% increase in xylanase production. Recombinant K. phaffii was able to use formate as a carbon source, indicating successful substitution of formate for methanol. Xylanase production, using the safe and sustainable formate as an inducer and carbon source, is a major advance in the field of industrial enzyme production. Key points: • Change to formate assimilation by recombinant K. phaffii instead of methanol • K. phaffii expressed xylanase by formate induction instead of methanol induction • Increased xylanase expression by transcription factor co-expression [ABSTRACT FROM AUTHOR]

Komagataella phaffii (K. phaffii) is a famous microbial cell of heterologous protein and value-added chemicals production because of its strict and strong promoter (alcohol oxidase 1 promoter, PAOX1). Formate is an attractive substitute of traditional inducer methanol because methanol is toxic and explosive. To obtain high level of Aspergillus niger ATCC1015 xylanase as a model of heterologous protein by K. phaffii at formate induction, insertion of three-copy cis-acting element W3A into PAOX1 additionally, and co-expression of transcription factor Mit1 under another PAOX1 were carried out separately and simultaneously. The yield of xylanase increased by 41% at formate induction when Mit1 was co-expressed. Furtherly, the yield of xylanase increased by 42% using sorbitol as supplemental carbon source with the result of 408.3 × 103 U‧L−1 xylanase. Therefore, a non-methanol needed and inducible heterologous protein expression system of Komagataella phaffii was developed successfully. [ABSTRACT FROM AUTHOR]

The capability to evaluate antibiotic residues in a sensitive, rapid, and reliable manner, is of great importance. Surface-enhanced Raman spectroscopy (SERS) is the phenomenon related to rough surface, which is used to effectively detect residual antibiotics in food. In this work, SERS strategy was used for the determination of antibiotic Benzylpenicillin sodium (NaBP) and Ampicillin (AMP) in the milk based on flower-like Ag nanoparticles, synthesized at 25 °C. A liner correlation was twigged between the SERS signal and the concentration for NaBP and AMP, with regression coefficient of 0.997 and 0.987. The limit of detection of NaBP and AMP residue based on this SERS-based detection, can be as low as 6.3 × 10–9 mol L−1 and 9.2 × 10–10 mol L−1, respectively. The presented method can be used for the determination of NaBP and AMP residue in milk. The recovery is 83–95% and 80–96%, and the relative standard deviation is 4.7–8.5% and 5.3–15.1%, respectively, which could be a simple method for the determination of antibiotic residues in animal derived food. [ABSTRACT FROM AUTHOR]

Developing a Komagataella phaffii (K. phaffii, named as Pichia pastoris formerly) medium using wheat bran hydrolysate (WBH) is a potential approach for wheat bran utilization and heterologous protein by K. phaffii because K. phaffii is used as protein producer by researchers and engineers widely. In this research, the detoxification process of WBH was optimized to obtain the final procedure as pH adjusting to 10 by calcium hydroxide addition, then, 2.0 g/L active carbon absorption followed by 1 h shaking and 3,600 × g centrifugation for 10 min, finally, 3.75 mmol/L sodium thiosulfate addition for 10 min shaking followed by 3,600 × g centrifugation for 10 min. Recombinant K. phaffii-xynB harboring xylanase B gene from Aspergillus niger ATCC 1015 under alcohol oxidase 1 promoter (PAOX1) was cultivated in detoxified WBH expressing 1059.8 U/mL xylanase B which was 90.9% of that in complex medium from Pichia protocols. These researches built a solid base for detoxified WBH as a low-cost medium of K. phaffii to express heterologous protein, also provided a bright outlet for wheat bran utilization. [ABSTRACT FROM AUTHOR]

A non-classical shape selective catalyst of short-H-TiNTs was synthesized by the hydrothermal method at 150 °C for 48 h and acid-assisted treatment of HCl solution (0.01–0.4 mol/L) The catalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption and Raman spectroscopy analyses, and their catalytic performances were studied in the presence of 1-octylene, methylbenzene, or cyclohexane in the model oil. These catalysts were able to remove almost all the sulfur-containing complex in diesel for 30 min with high selectivity, at 45 °C, n(H2O2) /n(4,6-DMDBT) molar ratio of 4, and v(oil)/v(methanol) = 1:1. And the improved catalytic active sites of Ti-η1-hydroperoxo complexes in short-H-TiNTs were supposed to the key reason of the high selectivity just like a shape selective catalyst. [ABSTRACT FROM AUTHOR]

A Pt counter electrode of dye-sensitized solar cells (DSSCs) was prepared by a simple and low-cost pulse electrodeposition method. The catalytic activity and the Pt utilization efficiency of Pt films were investigated. In this study, four Pt counter electrodes were prepared by pulse electrodeposition at high current density on FTO substrates. The catalytic activity of the counter electrode and DSSC performance were optimized by varying the pulse electrodepositing cycles. The relationships between Pt nanostructure, electrochemical properties, interfacial charge transfer resistance and photovoltaic performance are investigated in detail. The Pt film prepared by 25 pulse electrodepositing cycles shows well-distributed Pt nanoparticles on the FTO substrate, which provides not only a larger electrochemical active surface area but also lower charge transfer resistance than others. The photovoltaic performance proves that the Pt counter electrode prepared by 25 pulse electrodepositing cycles at 30 mA/cm current density achieves the highest energy conversion efficiency of 8.45% among these samples. [ABSTRACT FROM AUTHOR]

Well-dispersed Au/Bi nanoparticles with average size below 10 nm were prepared by using NaBH to reduce HAuCl with glucose as dispersant. The obtained Au/Bi NPs were well characterized by UV-Vis spectra, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements. The electrochemical study found that Bi adlayers on the surface of Au nanoparticles owns two kinds of surface structures, including a low coverage (2 × 2)-Bi adlayer and a close-packed (p × √3)-2 Bi adlayer due to the strong interaction between the two Bi layers and the below Au atoms, which is same with that bulk on Au surface. [ABSTRACT FROM AUTHOR]

A simple and efficient way to planarize Hastelloy substrate for high-temperature superconductors has been developed. The colloid-solution deposition planarization (CSDP) method consists of two steps: colloid deposition planarization and subsequent precursor solution deposition planarization. The surface roughness of Hastelloy belt decreased from 4.0 to 0.8 nm after YO colloid deposition and then to 0.3 nm after further yttrium acetate solution deposition. The shrinkage percentage of the colloid deposition layer and solution deposition layer was 20 and 77 %, respectively. Compared with traditional solution deposition planarization, the higher planarization efficiency of CSDP can be attributed to the lower shrinkage percentage of the colloid deposition layer. As a result, ion-beam-assisted deposition (IBAD)-MgO on Hastelloy substrate with CSDP coating showed crystal orientation. Hastelloy belt planarized by the CSDP method will provide a low-cost substrate for high-temperature superconductors. [ABSTRACT FROM AUTHOR]

Mesoporous composite films of titania (TiO) and antimony-doped tin oxide (ATO) were prepared on titanium plate substrates from pastes by the doctor-blade method. The photoelectrochemical properties of the samples with different ATO contents were investigated by the degradation of methylene blue under UV light irradiation. It was found that the photocatalytic activity of TiO was significantly improved with the help of the introduction of ATO nanocrystals and a forward bias. The synergetic effect of ATO and bias was analyzed by electrochemical impedance spectra (EIS). The EIS analysis results demonstrated that the separation of photogenerated electron-hole pairs can be efficiently enhanced by introducing ATO nanoparticles and applying an external bias. [ABSTRACT FROM AUTHOR]

SUZ-4 zeolite was synthesized by the dry gel conversion (DGC) process with water vapor as gas phase, and characterized by XRD, SEM and N adsorption. The dry gel was prepared with the assistance of a small amount of crystalline seed and organic template tetraethylammonium hydroxide (TEAOH). Molar ratios of SiO/AlO, KOH/SiO, TEAOH/SiO and HO/SiO, amounts of seed and dry gel, types of silica sources, and crystallization temperature and time, were changed to optimize synthesis conditions. The results show that the DGC method leads to formation of SUZ-4 zeolite in a broad range of crystallization temperature 120-180 °C. Under the optimal conditions, i.e., SiO/AlO = 22.5, KOH/SiO = 0.44, TEAOH/SiO = 0.044, HO/SiO = 22.2, seed amount = 0.1 wt%, fumed silica as the silica source, 160 °C and 5 days, SUZ-4 zeolite is obtained with a high crystallinity. Compared to hydrothermal synthesis, the present DGC approach employs far less amount of organic template and allows using inert fumed silica as silica source, producing smaller rod-like SUZ-4 zeolite crystals. [ABSTRACT FROM AUTHOR]

In this work, three kinds of Flocculant, microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC), and Chitosan (CTS), coating Fe-MOF were prepared by a coprecipitation method followed by an in situ graft copolymerization. When they employed as heterogeneous Fenton-catalysts to degrade phenol in waste water, their catalytic activity has the order of has the order of MIL-CMC (0.0873 min− 1) > MIL-MCC (0.0794 min− 1) > MIL-CTS (0.0712 min− 1) > MIL-88B (0.0675 min− 1). The reaction conditions were optimized, and found that the best reactions: MIL-CMC0.3 used as catalyst with catalyst load 20 mg/20ML, and the 25 ℃, pH = 3, and phenol of 100 ppm, could be removed completely in 5 min. Most important, Fe ions leakage of MIL: CMC is very small (0.02–0.03 mg/L), significantly less than that of MIL-88B (2.00-2.85 mg/L). The enhanced catalytic activity of Fe-MOF@flocculent could be attributed to flocculent protective action. [ABSTRACT FROM AUTHOR]