Constructing cuprous oxide-modified zinc tetraphenylporphyrin ultrathin nanosheets heterojunction for enhanced photocatalytic carbon dioxide reduction to methane.

The application of supermolecular naonostructures in the photocatalytic carbon dioxide reduction reaction (CO2RR) has attracted increasing attentions. However, it still faces significant challenges, such as low selectivity for multi-electron products and poor stability. Here, the cuprous oxide (Cu2O)-modified zinc tetraphenylporphyrin ultrathin nanosheets (ZnTPP NSs) are successfully constructed through the aqueous chemical reaction. Comprehensive characterizations confirm the formation of type-II heterojunction between Cu2O and ZnTPP in Cu2O@ZnTPP, and the electron transfer from Cu2O to ZnTPP through the Zn-O-Cu bond under the static contact. Under the visible-light irradiation (λ > 420 nm), the optimized Cu2O@ZnTPP sample as catalyst for photocatalytic CO2RR exhibits the methane (CH4) evolution rate of 120.9 µmol/g/h, which is âˆ¼ 4 and âˆ¼ 10 times those of individual ZnTPP NSs (28.0 µmol/g/h) and Cu2O (12.8 µmol/g/h), respectively. Meanwhile, the CH4 selectivity of âˆ¼ 98.7 % and excellent stability can be achieved. Further experiments reveal that Cu2O@ZnTPP has higher photocatalytic conversion efficiency than Cu2O and ZnTPP NSs, and the photoinduced electron transfer from ZnTPP to Cu2O can be identified via the path of ZnTPP→ (ZnTPP•ZnTPP)*→ ZnTPP-→ Zn-O-Cu â†’ Cu2O. Consequently, Cu2O@ZnTPP exhibits a shorter electron-hole separation lifetime (3.3 vs. 9.3 ps) and a longer recombination lifetime (23.1 vs. 13.4 ps) than individual ZnTPP NSs. This work provides a strategy to construct the organic nanostructures for photocatalytic CO2RR to multi-electron products.

Construction of Cobalt Porphyrin-Modified Cu2 O Nanowire Array as a Tandem Electrocatalyst for Enhanced CO2 Reduction to C2 Products.

Here, the molecule-modified Cu-based array is first constructed as the self-supporting tandem catalyst for electrocatalytic CO2 reduction reaction (CO2 RR) to C2 products. The modification of cuprous oxide nanowire array on copper mesh (Cu2 O@CM) with cobalt(II) tetraphenylporphyrin (CoTPP) molecules is achieved via a simple liquid phase method. The systematical characterizations confirm that the formation of axial coordinated Co-O-Cu bond between Cu2 O and CoTPP can significantly promote the dispersion of CoTPP molecules on Cu2 O and the electrical properties of CoTPP-Cu2 O@CM heterojunction array. Consequently, as compared to Cu2 O@CM array, the optimized CoTPP-Cu2 O@CM sample as electrocatalyst can realize the 2.08-fold C2 Faraday efficiency (73.2% vs 35.2%) and the 2.54-fold current density (-52.9 vs -20.8 mA cm-2 ) at -1.1 V versus RHE in an H-cell. The comprehensive performance is superior to most of the reported Cu-based materials in the H-cell. Further study reveals that the CoTPP adsorption on Cu2 O can restrain the hydrogen evolution reaction, improve the coverage of * CO intermediate, and maintain the existence of Cu(I) at low potential.

WeChat mini program in laboratory biosafety education among medical students at Guangzhou Medical University: a mixed method study of feasibility and usability.

BACKGROUND: Laboratory biosafety should be a priority in all healthcare institutions. In traditional laboratory safety teaching students typically receive knowledge passively from their teachers without active involvement. The combination of experiential learning and mobile learning may provide students with greater engagement, retention, and application of knowledge. To address this issue, we developed and conducted a convergent mixed methods study to assess the feasibility and usability of a WeChat mini program (WMP) named WeMed for laboratory biosafety education for medical laboratory students at Guangzhou Medical University (GMU). METHODS: The study was conducted between November 2022 and October 2023 among second-year undergraduate students at GMU. It involved the concurrent collection, analysis, and interpretation of both qualitative and quantitative data to assess feasibility and usability. In the quantitative strand, two evaluations were conducted via online surveys from students (n = 67) after a four-week study period. The System Usability Scale (SUS) was used to evaluate usability, while self-developed questions were used to assess feasibility. Additionally, a knowledge test was administered 6 months after the program completion. In the qualitative strand, fourteen semi-structured interviews were conducted, whereby a reflexive thematic analysis was utilized to analyze the interview data. RESULTS: The overall SUS score is adequate (M = 68.17, SD = 14.39). The acceptability of the WeMed program is in the marginal high range. Most students agreed that WeMed was useful for learning biosafety knowledge and skills (13/14, 93%), while 79% (11/14) agreed it was easy to use and they intended to continue using it. After 6 months, a significant difference in the knowledge test scores was observed between the WeMed group (n = 67; 2nd year students) and the traditional training group (n = 90; 3rd year students). However, the results should be interpreted cautiously due to the absence of a pretest. CONCLUSION: The combination of experiential learning and mobile learning with WMP is a feasible tool for providing laboratory biosafety knowledge and skills. Ongoing improvements should be made in order to increase long-term acceptance.

Composition, source, and influencing factors of white spots formation in soybean paste.

White spots are commonly found in bean-based fermented food, which will significantly lower the product quality. This study aimed to analyze the composition of white spots and further reveal the source and influencing factors of white spots in bean-based fermented food using soybean paste as study model. The results showed that white spots were mainly composed of 40.96% free tyrosine and 37.94% tyrosine in combination form. During soybean paste fermentation, tyrosine was found to be produced by the actions of proteolytic enzymes secreted by Aspergillus oryzae 3.042 instead of the microbial metabolism and the excessive accumulation of tyrosine in soybean paste led to the formation of white spots. Among all influencing factors, high temperature treatment favored the formation of white spots. The existence of soy peptone and phenylalanine would postpone the precipitation of tyrosine while promoting the aggregation of the tyrosine precipitation. Field emission scanning electron microscope analysis showed that tyrosine would accumulate around the soybean protein particles and treatment at 120 °C would disrupt the structure of tyrosine-protein complex. Based on the above results, we proposed that treatment of soybean paste at temperature lower than 80 °C was the current practically applicable method to control the formation of white spots in soybean paste. PRACTICAL APPLICATION: This study developed a new idea to understand the composition and formation of white spots in soybean paste, which would provide guidance for prevention and control of white spots during the production of soybean paste for manufacturers and researchers.

Adaptive evolution of Aspergillus oryzae 3.042 strain and process optimization to reduce the formation of tyrosine crystals in broad bean paste.

Tyrosine crystals occasionally appeared on the broad bean paste surface, which will cause economic losses. This study aimed to eliminate the tyrosine crystals in broad bean paste through decreasing the activities of proteolytic enzymes produced by Aspergillus oryzae and process optimization. Broad bean pastes containing no more than 6.16 mg/g dry material tyrosine showed low possibility to form tyrosine crystals. Using tyrosine as substrate, the A. oryzae 3.042 was adaptively evolved and the tyrosine content in the broad bean paste fermented by the evolved A. oryzae was reduced from 6.49 mg/g dry material to 6.14 mg/g dry material (p < 0.05). When the production process was optimized, the tyrosine content in broad bean paste was further reduced to 5.67 mg/g dry material (p < 0.05). In this condition, no tyrosine crystals were formed in broad bean paste after the 12-month storage while the product quality was not influenced. PRACTICAL APPLICATIONS: Tyrosine crystals were one of the most important factors which negatively influence the quality of traditionally fermented food, including broad bean paste, soybean paste, and sausages. The appearance of tyrosine crystals in these foods will cause economic losses to manufacturers. This study tried to eliminate the appearance of tyrosine crystals through decreasing the activities of proteolytic enzymes produced by Aspergillus oryzae 3.042 and fermentation process optimization. The adoption of modified A. oryzae and optimized fermentation process successfully guaranteed the elimination of tyrosine crystals formation in the production and storage period of broad bean paste. This will not only benefit the broad bean paste manufacturers but also provide guidance for other fermented food producers to deal with tyrosine crystals problem.