Search

TiO2-based photocatalysts are eco-friendly, cost-effective, and stable but only exert catalytic performance in the ultraviolet region, and the photocatalytic efficiency is very low. In this work, we employ DFT calculations to deeply investigate the effect of nonmetallic C-doped TiO2 (101) on the photocatalytic hydrogen evolution performance. Specifically, the effects of C substitution or interstitial doping at the surface, subsurface, and bulk on the electronic structure, optical properties, and catalytic hydrogen evolution activity were substantially investigated. We discovered that different C atom doping strategies impinge different effects on the catalytic activity. Among them, the CO-bulk4, CTi-surf2, and Cinter-surf systems showed superior catalytic activities with ΔG of −0.012, −0.055, and −0.024 eV, respectively. The C atom replaces the Ti atom and alters the original coordination environment, which leads to charge redistribution and consequently to the activation of the O sites. Additionally, carbon-self-doped TiO2 photocatalysts were fabricated using an experimental hydrothermal synthesis, and the XPS analyses confirmed that O is replaced by C. In addition, the photocatalytic hydrogen evolution rate is 0.3 mmol g–1 h–1, while there is no hydrogen evolution for pure TiO2. Our findings suggest that nonmetallic doped TiO2(101) photocatalysts can improve light absorption, modulate charge distribution, and enhance hydrogen evolution activity. [ABSTRACT FROM AUTHOR]

Successful oral insulin administration can considerably enhance the quality of life (QOL) of diabetes patients who must frequently take insulin injections. Oral insulin administration, on the other hand, is seriously hampered by gastrointestinal enzymes, wide pH range, mucus and mucosal layers, which limit insulin oral bioavailability to ≤ 2%. Therefore, a large number of technological solutions have been proposed to increase the oral bioavailability of insulin, in which polymeric nanoparticles (PNPs) are highly promising for oral insulin delivery. The recently published research articles chosen for this review are based on applications of PNPs with strong future potential in oral insulin delivery, and do not cover all related work. In this review, we will summarize the controlled release mechanisms of oral insulin delivery, latest oral insulin delivery applications of PNPs nanocarrier, challenges and prospect. This review will serve as a guide to the future investigators who wish to engineer and study PNPs as oral insulin delivery systems. [ABSTRACT FROM AUTHOR]

A novel electrochemical method has been developed, based on a covalent organic framework (COF) and reduced graphene oxide (rGO), to detect fentanyl and alfentanil. COF nanomaterials with chrysanthemum morphology obtained by solvothermal reaction contain rich active sites for electrochemical catalytic reaction, thus improving the detection performance of the designed sensor. Reduced graphene oxide improves the sensor's sensitivity due to enhanced electron transfer. Under optimized experimental conditions, the fabricated electrode presents a linear range of 0.02 to 7.26 μM for alfentanil and 0.1 to 6.54 μM for fentanyl, with detection limits of 6.7 nM and 33 nM, respectively. In addition, the sensor possesses excellent selectivity, outstanding reproducibility, and acceptable stability. The proposed sensor is feasible for the reliable monitoring of fentanyl and alfentanil in human serum samples, with acceptable reliability and high potential in real-world applications. Finally, the electrochemical characteristic fingerprint of fentanyl is investigated by studying the electrochemical behavior of alfentanil and fentanyl on the electrode surface. [ABSTRACT FROM AUTHOR]

A high-quality remote sensing interpretation dataset has become crucial for driving an intelligent model, i.e., deep learning (DL), to produce land-use/land-cover (LULC) products. The existing remote sensing datasets face the following issues: the current studies (1) lack object-oriented fine-grained information; (2) they cannot meet national standards; (3) they lack field surveys for labeling samples; and (4) they cannot serve for geographic engineering application directly. To address these gaps, the national-standards- and DL-oriented raster and vector benchmark dataset (RVBD) is the first to be established to map LULC for conducting soil water erosion assessment (SWEA). RVBD has the following significant innovation and contributions: (1) it is the first second-level object- and DL-oriented dataset with raster and vector data for LULC mapping; (2) its classification system conforms to the national industry standards of the Ministry of Water Resources of the People's Republic of China; (3) it has high-quality LULC interpretation accuracy assisted by field surveys rather than indoor visual interpretation; and (4) it could be applied to serve for SWEA. Our dataset is constructed as follows: (1) spatio-temporal-spectrum information is utilized to perform automatic vectorization and label LULC attributes conforming to the national standards; and (2) several remarkable DL networks (DenseNet161, HorNet, EfficientNetB7, Vision Transformer, and Swin Transformer) are chosen as the baselines to train our dataset, and five evaluation metrics are chosen to perform quantitative evaluation. Experimental results verify the reliability and effectiveness of RVBD. Each chosen network achieves a minimum overall accuracy of 0.81 and a minimum Kappa of 0.80, and Vision Transformer achieves the best classification performance with overall accuracy of 0.87 and Kappa of 0.86. It indicates that RVBD is a significant benchmark, which could lay a foundation for intelligent interpretation of relevant geographic research about SWEA in the Yangtze River Basin and promote artificial intelligence technology to enrich geographical theories and methods. [ABSTRACT FROM AUTHOR]

The construction of a genetic circuit requires the substitution and redesign of different promoters and terminators. The assembly efficiency of exogenous pathways will also decrease significantly when the number of regulatory elements and genes is increased. We speculated that a novel bifunctional element with promoter and terminator functions could be created via the fusion of a termination signal with a promoter sequence. In this study, the elements from a Saccharomyces cerevisiae promoter and terminator were employed to design a synthetic bifunctional element. The promoter strength of the synthetic element is apparently regulated through a spacer sequence and an upstream activating sequence (UAS) with a ~5-fold increase, and the terminator strength could be finely regulated by the efficiency element, with a ~5-fold increase. Furthermore, the use of a TATA box-like sequence resulted in the adequate execution of both functions of the TATA box and the efficiency element. By regulating the TATA box-like sequence, UAS, and spacer sequence, the strengths of the promoter-like and terminator-like bifunctional elements were optimally fine-tuned with ~8-fold and ~7-fold increases, respectively. The application of bifunctional elements in the lycopene biosynthetic pathway showed an improved pathway assembly efficiency and higher lycopene yield. The designed bifunctional elements effectively simplified pathway construction and can serve as a useful toolbox for yeast synthetic biology. [ABSTRACT FROM AUTHOR]

MIL-125, a titanium-based metal–organic framework (MOF) material with ultra-high specific surface area, large porosity, tunable structure, modifiable functionality, and multiple active sites, is commonly researched in the field of photocatalytic hydrogen evolution. However, MIL-125 still could not be directly used for practical application in photocatalytic hydrogen evolution because of its limited photoresponse. Therefore, it is necessary to systematically summarize the research on MIL-125 in the field of photocatalytic hydrogen evolution for its further development as well as that of other MOF materials. For MIL-125 photocatalysts, further modifications for promoting the photocatalytic activity of photocatalysts and improving the stability of photocatalysts are needed. Typical modification methods of MIL-125 include engineering functional groups and surface structure, doping metal ions, loading cocatalysts, and structuring composites. In this review, the research progress of MIL-125 in the field of photocatalytic hydrogen evolution is summarized, including its modification methods, photocatalytic hydrogen evolution activities, and micro-mechanisms. In view of the deficiencies and limitations of the current research, future developments of MIL-125 are prospected. [ABSTRACT FROM AUTHOR]

Triethylamine (TEA) exists widely in production and life and is extremely volatile, which seriously endangers human health. It is required to develop high-performance TEA sensors to protect human health. We fabricated Pt-Co3O4/WO3 based on our previous work, and the performance was tested against volatile organic compounds. Compared with the previous work, its operating temperature was greatly reduced from 240 °C to 180 °C. The response value of Pt-Co3O4/WO3 was increased from 1101 to 1532 for 10 ppm TEA with good selectivity. These results show a significant step toward practical use of the Pt-Co3O4/WO3 sensor. [ABSTRACT FROM AUTHOR]

All-inorganic lead-doped quantum dots (QDs) are widely used in various optoelectronic device materials due to their excellent optoelectronic properties. However, their poor stability and toxicity issues limit their further development. The glass-ceramic used as a carrier for Sn-doped QDs can overcome the bottleneck and maintain good luminescence properties as well. Here, lead-free perovskite QDs glass-ceramics with good performance in a borosilicate (B2O3–SiO2–ZnO) system were successfully prepared using a high-temperature melting method. They exhibit high stability against moisture and high fluorescence efficiency with a quantum yield of over 50%. By changing the doping of the halide (F, Cl, Br) in the glass matrix, tunable emission colors of the QDs glass-ceramics were achieved. Furthermore, the self-crystallized CsSnBr3 QDs glass-ceramics had good water stability, and maintained 72% of their initial fluorescence intensity in water after 40 days. The synergistic effect of lead-free QDs and SnO2 in glass-ceramics also demonstrated an ultra-broadband emission spectrum (300–900 nm) with white light emission, indicating great prospects for white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Purpose: Industrial and agricultural processing of licorice has produed a considerable quantity of residues, which are normally discarded randomly or treated by landfill. The residual active components in licorice residues including flavonoids were wasted. More seriously, the obstruction of lignocellulose in the residues has brought a huge challenge for efficient extraction of remaining flavonoids. Here, solid-state fermentation was thus developed to treat licorice residues for enhancing the flavonoids extraction. Methods: Focusing on the production of cell-wall degrading enzymes including pectinase, exocellulase and laccase, Lichtheimia ramose and white rot fungus were selected for solid-state mixed fermentation. The extraction of flavonoids was enhanced through optimizing the condition of solid-state mixed fermentation. Results: Under the inoculation ratio 1:1 of Lichtheimia ramose and white rot fungus with an inoculum concentration 10%, moisture content of 50% (w/w), nitrogen source content 20% (urea: NH4NO3 1:2), optimal activities of exocellulase, pectinase and laccase were obtained, which were 60.31 U/g, 65.99 U/g and 62.30 U/g respectively. The FT-IR confirmed the effective removal of lignin and hemicellulose. The SEM revealed a rough morphology with cracks and appearance of ruffles in fermented licorice residues, implying the destruction of lignocellulose by fermentation. After mixed fermentation, three new flavonoids including glabrone, isoflavone and licochalcone A were detected and identified by UHPLC-Q-TOF–MS. The extracted liquiritigenin increased by 75% compared with unfermented licorice residues. Conclusion: Mixed fermentation efficiently enhanced the release of flavonoids from licorice residues through destroying the compact structure of lignocellulose, demonstrating the application potential of solid-state fermentation technology in improving the extraction of active components from medicine residues. [ABSTRACT FROM AUTHOR]

Detecting 1 ppm acetone at high humidity is essential for a noninvasive diabetes diagnosis. Metal oxide gas sensors are a promising technology to achieve high sensitivity acetone monitoring. Here, we fabricated Pt-sensitized In2O3 nanotubes, and the gas-sensing performance was tested against eight gases. The fiber structure contributes to the uniform dispersion of Pt onto the In2O3. Pt-sensitized In2O3 nanotubes have lower optimal operating temperatures and higher sensitivity and selectivity than those of the In2O3 nanotubes. The 0.75 wt % Pt-In2O3 sensor has the maximum sensitivity (113) to 10 ppm acetone at 300 °C; the response and response time to 1 ppm acetone are 19.9 and 10 s, respectively. The response to 1 ppm acetone still has 9.83 at the relative humidity of 83%. It also has a low limit of detection (8.4 ppb) and good long-term stability (30 days). These results illustrate that Pt-sensitized In2O3 nanotubes have the potential for a noninvasive diabetes diagnosis. [ABSTRACT FROM AUTHOR]

Licorice residue, a considerable amount of biomass waste discarded during the excellent extraction process of traditional Chinese medicine every year, is a potential low-cost and green material for the synthesis of porous carbon material. In this work, spinel phase NiCo2O4 nanosheets were produced on the licorice residue-derived nitrogen-doped carbon aerogel (LNCA) using simple hydrothermal and calcination methods. LNCA was first prepared from the carbonation of freeze-dried licorice residue aerogel, which was subsequently utilized to prepare an LNCA/NiCo2O4 composite employing hydrothermal reaction and annealing treatment. As a consequence of its properties, the as-prepared hybrid electrode exhibited ultrahigh capacitance specific capacity (956 F g−1 at 1 A g−1) and long-term stability. This work provides some new insights on the preparation of biomass-derived porous carbon for application in supercapacitors, as well as multifaced considerations. [ABSTRACT FROM AUTHOR]

Photodegradation of aqueous organic pollutants is a very promising strategy to address environmental Issues and energy problems. In this paper, the latest research progress of photocatalytic degradation of organic pollutants in recent years was introduced, focusing on titanate photocatalyst, tantalum photocatalyst, niobate photocatalyst, inorganic layered compounds, metal sulfides, and Z-type photocatalytic reaction system. The problems and feasible solutions of degradation of organic pollutants by metal chalcogenide catalysts were summarized, and the future research work on visible light photocatalytic degradation of organic pollutants was prospected. [ABSTRACT FROM AUTHOR]

Iron acquisition by bacteria is well studied, but iron export from bacteria is less understood. Herein, we identified dr1440 with a P-type ATPase motif as a potential exporter of iron from Deinococcus radiodurans, a bacterium known for its extreme resistance to radiation and oxidants. The DR1440 was located in cell membrane as demonstrated by fluorescence labelling analysis. Mutation of dr1440 resulted in cellular accumulation of iron ions, and expression level of dr1440 was up-regulated significantly under iron ion or hydrogen peroxide stress in the wild-type strain, implicating DR1440 as a potential iron efflux protein. The dr1440 mutant displayed higher sensitivity to iron ions and oxidative stresses including hydrogen peroxide, hypochlorous acid, and gamma-ray irradiation compared with the wild-type strain. The high amount of iron in the mutant strain resulted in severe protein carbonylation, suggesting that DR1440 might contribute to intracellular protein protection against reactive oxygen species (ROS) generated from ferrous ion-mediated Fenton-reaction. Mutations of S297A and C299A led to intracellular accumulation of iron, indicating that S297 and C299 might be important functional residues of DR1440. Thus, DR1440 is a potential iron efflux protein involved in iron homeostasis and oxidative stress-resistance of D. radiodurans. [ABSTRACT FROM AUTHOR]

Various antibiotics have been extensively used to treating infectious diseases in hospitals. In this study, the abundance and diversity of antibiotics and antibiotic resistance genes (ARGs) were observed in the wastewater samples from five hospitals in Xinjiang, China. The total concentrations of tetracyclines, sulphonamides, and quinolones in hospital influents ranged from 363.4 to 753.3 ng/L, 285.5 to 634.9 ng/L, and 1355.8 to 1922.4 ng/L, respectively. However, the removal efficiency of tetracyclines, sulphonamides, and quinolones in wastewater treatment processes ranged from 72.4 to 79.3 %, 36.0 to 52.2 %, and 45.1 to 55.4 %, respectively. The contamination levels of the selected ARGs varied in all wastewater samples. The highest relative concentrations of sul1, sul2, tetQ, and qnrS were significantly higher than those of other ARGs in this study. Significant positive correlations between the relative abundance of partial ARGs and concentrations of certain antibiotics were observed in hospital wastewaters. Results show that integrons played an important role in disseminating and distributing ARGs in microorganism systems. Furthermore, strong correlations were observed between tetQ, sulphonamide resistance genes (except sulA) and intI1. This study aimed to determine the contamination levels of antibiotics and ARGs and analyze the relationships among ARGs, and antibiotics and integron genes in hospital wastewaters. [ABSTRACT FROM AUTHOR]

Triterpenoids are a highly diverse group of natural products and used particularly as medicine. Here, a strategy combining stepwise metabolic engineering and transcriptional control was developed to strengthen triterpenoid biosynthesis in Saccharomyces cerevisiae. Consequently, an efficient biosynthetic pathway for producing β-amyrin, a commercially valuable compound and precursor of triterpenoids, was constructed through expressing a plant-derived β-amyrin synthase. Introducing a heterologous squalene monooxygenase greatly dragged intermediate metabolite squalene toward β-amyrin. Increasing squalene pool by overexpressing IPP isomerase, FPP, and squalene synthase further enhanced β-amyrin synthesis of 49-folds. Through reconstructing the promoters with the binding site of transcription factor UPC2, directed transcriptional regulation on engineered pathway was availably achieved, resulting in β-amyrin titer increased by 65-folds. Using ethanol fed-batch fermentation, β-amyrin titer was finally improved up to 138.80 mg/L with a yield of 16.30 mg/g dry cell, almost 185 and 232 and folds of the initially engineered strain, respectively. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3172-3179, 2015 [ABSTRACT FROM AUTHOR]

The blend film is a favorable coating material for control-release fertilizer. The biodegradable blend film had been prepared by cross-linking carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA). The results showed that the increase of the PVA content made water absorbency, water permeability andpermeability of the blend films decrease. The increase of formaldehyde resulted in the decrease of absorbency and permeability. The cross-linking reaction between PVA and CMC was confirmed using X-ray diffraction and Fourier transform infrared absorption spectra. The prepared CMC/PVA blend film had the smooth surface. The good biodegradability implies that the CMC/PVA blend film may be a potential coating material for the application in the control-release fertilizer. [ABSTRACT FROM PUBLISHER]

In this work, TiO2 photocatalysts, co-doped with transition metal ions vanadium (V) and cobalt (Co) ((V,Co)–TiO2), were synthesized by the sol–gel method. The synthesized photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption and desorption measurement, UV-Vis absorption and photoluminescence spectrum (PL) spectra. The results show that V and Co co-doping has significant effects on sample average crystalline grain size, absorption spectrum, recombination efficiency of photo-induced electron-hole pairs (EHPs), and photocatalytic degradation efficiency of methylene blue (MB). (V,Co)–TiO2 photocatalyst exhibits an obvious red shift of the absorption edge to 475 nm. Photocatalytic degradation rate of (V,Co)–TiO2 sample for MB in 60 min is 92.12% under a Xe lamp with a cut-off filter (λ > 400 nm), which is significantly higher than 56.55% of P25 under the same conditions. The first principles calculation results show that V and Co ions doping introduces several impurity energy levels, which can modulate the location of the valence band and conduction band. An obvious lattice distortion is produced in the meantime, resulting in the decrease in photo-generated EHP recombination. Thus, (V,Co)–TiO2 photocatalyst performance is significantly improved. [ABSTRACT FROM AUTHOR]

Background: The La-related protein 1 (LARP1) has been found to be a RNA binding protein and was related to spermatogenesis, embryogenesis and cell-cycle progression. The aim of this study was to investigate the prognostic value of LARP1 in hepatocellular carcinoma (HCC).Methods: LARP1 expression was examined in 15 HCC cell lines and 272 clinical specimens using real-time PCR, immunohistochemistry (IHC) and western blot analysis (WB). LARP1 expression was also studied in 6 paired HCC lesions and the adjacent non-cancerous tissue samples. Statistical analyses were applied to derive association between LARP1 expression scores and clinical characters as well as patient survival.Results: mRNA and protein levels of LARP1 were higher in HCC cell lines and HCC lesions than in normal liver epithelial cells and the paired adjacent noncancerous tissues. LARP1 expression was correlated to survival time, vital status, tumor size and Child-Pugh score. Overall survival analysis showed HCC patients with high LARP1 expression level had lower survival rate (P<0.01). Importantly, this correlation remained significant in patients with early-stage HCC or with normal serum AFP level.Conclusions: LARP1 protein may represent a promising biomarker for predicting the prognosis of HCC, including in early-stage and AFP-normal patients. [ABSTRACT FROM AUTHOR]