Herein, Cu was incorporated into ZnO lattice to reduce its band gap as well as to extend its visible radiation response. The obtained Cu-ZnO was continuously integrated with g-C3N4 to create ...Cu-ZnO/g-C3N4Z-direct scheme photocatalyst for advanced atrazine removal. Radical scavenging experiments have been also conducted to clearly figure out photocatalytic mechanism for degradation of atrazine by the synthesized photocatalyst. The synthesized Cu-ZnO only utilized the generated h+ for atrazine degradation (direct and indirect via formation hydroxyl radicals (•OH)) and the g-C3N4 only utilized the generated e− for atrazine degradation (indirect via reaction with O2 to form superoxide anion, which needed to continuously react with H2O to form •OH). Therefore, the photocatalytic atrazine degradation by synthesized Cu-ZnO material was greater than that by synthesized g-C3N4 material. Cu-ZnO/g-C3N4 utilized both generated e− and h+ for degradation of atrazine. Thus, the photocatalytic atrazine degradation by the synthesized Cu-ZnO/g-C3N4 was greater than those of single g-C3N4 or Cu-ZnO materials. Finally, the conducted recycling experiments indicated great stability of synthesized Cu-ZnO/g-C3N4 during long-term atrazine degradation process opening new era for application of the material in practical systems.
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•Cu doped into ZnO lattice to reduce its band gap and to extend its visible radiation response.•Cu-ZnO was successfully combined with g-C3N4 to establish Z direct scheme system.•Z-scheme prevented fast recombination of e− and h+ and maintained their re-dox potential.•The Cu-ZnO/g-C3N4 utilized both generated e− and h+ for degradation of atrazine.•The Cu-ZnO/g-C3N4 showed excellent activity and stability during long-term photocatalysis.
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In this study, we firstly aimed to use Nb as dopant to dope into the TiO2 lattice in order to narrow band gap energy or enhance photocatalytic activity of the Nb-TiO2. Then, the ...prepared Nb-TiO2 was combined with g-C3N4 to establish Nb-TiO2/g-C3N4 direct Z-scheme system for superior reduction of CO2 into valuable fuels even under visible light. The obtained results indicated that the band gap energy of the Nb-TiO2 (2.91 eV) was lower than that of the TiO2 (3.2 eV). In the successfully established Nb-TiO2/g-C3N4 direct Z-scheme system, the photo-excited e− in the CB of the Nb-TiO2 combined with the photo-excited h+ in the VB of the g-C3N4 preserving the existence of e− in the CB of the g-C3N4 and h+ in the VB of Nb-TiO2, and thereby, the system produced numerous amount of available e−/h+ pairs for the reduction of CO2 into various valuable fuels. In addition, the produced e− of the Nb-TiO2/g-C3N4 existing in the CB of the g-C3N4, which the potential energy is approximately −1.2 V, would be strong enough for the reduction of CO2 to generate not only CH4 and CO but also HCOOH. Among established Nb-TiO2/g-C3N4 materials, the 50Nb-TiO2/50 g-C3N4 material was the best material for the CO2 reduction.
Herein, g-C3N4 and NiMoO4, which are moderate energy band gap semiconductors, have been effectively hybridized to create Z scheme heterojunction for successful visible-light photocatalytic converting ...CO2 into valuable products including CH4, CO, O2 and HCOOH. Ni(NO3)2·6H2O and (NH4)6Mo7O24·4H2O were used as precursors to synthesize NiMoO4 photocatalyst, which was continuously mixed with melamine before calcinating at 520 °C for 6 h to get NiMoO4/g-C3N4 Z scheme heterojunction. We explored that NiMoO4 intimately contacted with g-C3N4. These band positions of the NiMoO4 were also perfectly matched with those of the g-C3N4. Therefore, these photo-induced e− on conduction band of the NiMoO4 could easily travel to h+ on valence band of the g-C3N4 (recombination); thereby, minimize h+ and e− recombination in each material. Therefore, the NiMoO4/g-C3N4 direct Z-scheme heterojunctions could produce significant available h+ on the valence band of the NiMoO4 and e− on the conduction band of the g-C3N4. These e−/h+ have suitable redox potential to effectively convert CO2. Finally, the optimized g-C3N4 mole ratio for maximum enhancing photocatalytic efficiency of the NiMoO4/g-C3N4 heterojunction was 60%. When the g-C3N4 content increased to 70%, the excess g-C3N4 amount would entirely cover NiMoO4 surface leaded to form dense and closed shell. The formed closed shell decreased contact between NiMoO4 and CO2 as well as the interface charge transfer, which reduced the e− and h+ separation and transfer leading to decrease in photocatalytic conversion efficiency.
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•Successfully created NiMoO4/g-C3N4 Z scheme heterojunction for CO2 conversion.•Hybridization of NiMoO4 and g-C3N4 prevented recombination of e−/h+ in each material.•The created NiMoO4/g-C3N4 converted CO2 into HCOOH, CH4 and CO even under visible light.•The optimal molar ratio of g-C3N4/NiMoO4 for the best photocatalytic conversion was 60%.
BACKGROUND:Probiotics are the most frequently prescribed treatment for children hospitalized with diarrhea in Vietnam. We were uncertain of the benefits of probiotics for the treatment of acute ...watery diarrhea in Vietnamese children.
METHODS:We conducted a double-blind, placebo-controlled, randomized trial of children hospitalized with acute watery diarrhea in Vietnam. Children meeting the inclusion criteria (acute watery diarrhea) were randomized to receive either 2 daily oral doses of 2 × 10 CFUs of a local probiotic containing Lactobacillus acidophilus or placebo for 5 days as an adjunct to standard of care. The primary end point was time from the first dose of study medication to the start of the first 24-hour period without diarrhea. Secondary outcomes included the total duration of diarrhea and hospitalization, daily stool frequency, treatment failure, daily fecal concentrations of rotavirus and norovirus, and Lactobacillus colonization.
RESULTS:One hundred and fifty children were randomized into each study group. The median time from the first dose of study medication to the start of the first 24-hour diarrhea-free period was 43 hours (interquartile range, 15–66 hours) in the placebo group and 35 hours (interquartile range, 20–68 hours) in the probiotic group (acceleration factor 1.09 95% confidence interval, 0.78–1.51; P = 0.62). There was also no evidence that probiotic treatment was efficacious in any of the predefined subgroups nor significantly associated with any secondary end point.
CONCLUSIONS:This was a large double-blind, placebo-controlled trial in which the probiotic underwent longitudinal quality control. We found under these conditions that L. acidophilus was not beneficial in treating children with acute watery diarrhea.
A new iridoid glucoside, moridoside (1), and nine known compounds, asperulosidic acid (2), 6-O-epi-acetylscandoside (3), geniposidic acid (4), 2-hydroxymethylanthraquinone (5), ...2-hydroxymethyl-3-hydroxyanthraquinone (6), damnacanthol (7), lucidine-ω-methyl ether (8), 2-hydroxy-1-methoxyanthraquinone (9), and 3,8-dihydroxy-1,2-dimethoxyanthraquinone (10) were isolated from the methanol extract of Morinda officinalis How. roots. Their structural identification was carried out based on the spectroscopic evidence. All compounds were evaluated for their nitric oxide (NO) production inhibitory activities in LPS-stimulated RAW264.7 macrophages. Compounds 5-7 significantly inhibited the production of NO with IC
50
values of 28.4, 33.6, and 30.5 μM, respectively.
Identifying polyps is challenging for automatic analysis of endoscopic images in computer-aided clinical support systems. Models based on convolutional networks (CNN), transformers, and their ...combinations have been proposed to segment polyps with promising results. However, those approaches have limitations either in modeling the local appearance of the polyps only or lack of multi-level feature representation for spatial dependency in the decoding process. This paper proposes a novel network, namely ColonFormer, to address these limitations. ColonFormer is an encoder-decoder architecture capable of modeling long-range semantic information at both encoder and decoder branches. The encoder is a lightweight architecture based on transformers for modeling global semantic relations at multi scales. The decoder is a hierarchical network structure designed for learning multi-level features to enrich feature representation. Besides, a refinement module is added with a new skip connection technique to refine the boundary of polyp objects in the global map for accurate segmentation. Extensive experiments have been conducted on five popular benchmark datasets for polyp segmentation, including Kvasir, CVC-Clinic DB, CVC-ColonDB, CVC-T, and ETIS-Larib. Experimental results show that our ColonFormer outperforms other state-of-the-art methods on all benchmark datasets.
In recent years, serosurveillance has gained momentum as a way of determining disease transmission and immunity in populations, particularly with respect to vaccine-preventable diseases. At the end ...of 2017, the Oxford University Clinical Research Unit and the National Institute of Hygiene and Epidemiology held a meeting in Vietnam with national policy makers, researchers, and international experts to discuss current seroepidemiologic projects in Vietnam and future needs and plans for nationwide serosurveillance. This report summarizes the meeting and the plans that were discussed to set up nationwide serosurveillance in Vietnam.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A novel iron-modified biochar (FMBC) derived from rice straw was synthesized using FeCl3 modification for efficient As(V) removal from aqueous solution. FTIR and SEM-EDX analyses were carried out to ...determine the mechanism involved in the removal process and also demonstrated that Fe had loaded successfully on the surface of modified biochar. The iron-modified biochar showed higher arsenic removal ability than the raw biochar. The iron-modified biochar showed a maximum adsorption with an initial solution pH of 5.0. Moreover, for the tested biochar, the As(V) removal kinetics data were well fitted by the pseudo-second-order model. Furthermore, the As(V) removal data upon being well fitted by the Langmuir model showed the maximal removal capacity of 28.49 mg/g. The simple preparation process and high adsorption performance suggest that the iron-modified biochar derived from rice straw could be served as an effective, inexpensive, and environmentally sustainable adsorbent to replace typical granular activated carbon (AC) for As(III) removal from aqueous solution.
In the study, we used two conducting polymers, polyaniline (PANI) and polypyrrole (PPy), to sensitize Ta3N5, thereby enhancing its photocatalytic activity, and then applied this novel photocatalyst ...to overall water splitting to produce hydrogen and oxygen even under visible light irradiation. The two polymers increased the charge transfer efficiency, prevented the recombination of the generated electrons and holes of the Ta3N5 photocatalyst, and thereby enhanced its electron-hole separation efficiency and improved its photocatalytic activity for efficient visible light water splitting. The two polymers completely covering the Ta3N5 particles facilitated charge transfer for quick migration of the generated electrons and holes to the polymer surface and thus prevented contact between the holes and nitride of Ta3N5. Therefore, these conducting polymers also protected the Ta3N5 particles from self-photocorrosion during long-term water splitting. Because of the existence of the protonated nitrogen (-N+) state in PPy, the electric conductivity of PPy was lower than that of PANI, which lowered the sensitizing ability of PPy compared to that of PANI. Thus, the water splitting efficiency of Ta3N5/PANI was higher than that of Ta3N5/PPy. The production rates of H2 and O2 generated from water splitting of Ta3N5/PANI were 60.5 and 30.2 (μmol. g−1cat. h−1), respectively.
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•Polymer sensitizers enhanced the separation of e−/h+ pairs and prolonged the Ta3N5 lifetime.•Polymer cover protected Ta3N5 from self-photocorrosion (oxidation of generated holes).•Ta3N5/polymers greatly exhibited overall photocatalytic water splitting.•Lower electric conductivity lowered the sensitizing ability of the polymer.•PANI was better than PPy for enhancing the photocatalytic activity of Ta3N5.
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