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Highly fluorescent covalent organic frameworks (COFs) are rarely obtained because of the π–π stacked layers with aggregation-caused quenching behavior. Unarguably, highly fluorescent COFs with tunable emission colors are even more rarely achieved. Herein, a general strategy to modify the classical COF material (named COF-1) by different fluorescent molecules via N → B interaction was developed. In this method, the boron-containing COF-1 acted as a porous and crystalline matrix as well as a reaction partner of Lewis acid; after interacting with fluorescent molecules with the anchoring group of pyridine (Lewis base), COF-1 takes a gorgeous transfiguration from a non-emissive powder into a highly fluorescent COF material with tunable emission colors. This disclosed method endowed the typical COFs with new emissive life and is speculated with the general research concept for all boron-containing COFs. Benefiting from the prominent fluorescent emission in the aggregation state, sensitive probes toward amines are achieved.

AbstractAscorbic acid is often used to enhance iron absorption in nutritional interventions, but it produces pro-oxidant effects in the presence of iron. This study aimed to evaluate ascorbate’s role in iron toxicity on intestinal resistance against foodborne pathogens during iron supplementation/fortification. In polarized Caco-2 cell monolayers, compared to the iron-alone treatment, the iron-ascorbate co-treatment caused more than 2-fold increase in adhesion, invasion and translocation of Salmonella entericaserovar Typhimurium. According to 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide assay, lactate dehydrogenase release and transepithelial electrical resistance, the iron-ascorbate co-treatment resulted in reduced cell viability and increased impairment of cell membrane and paracellular permeability compared to the iron-alone treatment. Butylated hydroxytoluene protected cells against these prooxidant toxicities of ascorbate. Ascorbate completely restored iron-induced intracellular oxidant burst and depletion of cytosolic antioxidant reserve, according to dichlorodihydrofluorescein fluorescence and intracellular reduced glutathione levels. In Salmonella-infected C57BL/6 mice, iron-ascorbate co-supplementation resulted in greater loss of body weight and appetite, lower survival rate, shorter colon length, heavier intestinal microvilli damage, and more intestinal pathogen colonization and translocation than the iron-alone supplementation. Overall, ascorbate would exacerbate iron toxicity on intestinal resistance against Salmonellainfection through pro-oxidant impairment of intestinal epithelial barrier from extracellular side and/or by facilitating intestinal pathogen colonization.

Gas separation performance of glassy polymers can be improved by enhancing the polymer backbone stiffness to decrease the chain packing and increase the free volume and gas permeabilities. In this work, two Tröger’s base (TB)-based polymers were prepared by polymerization from two spirobichroman-containing diamine monomers, MSBC and SBC. The obtained TB-based polymers show good solubility in polar aprotic solvents including DMF, DMAc, NMP, and DMSO, high molecular weight, and high thermal stability. Gas separation performance of TB-MSBC and TB-SBC are much better than those of the 6FDA-MSBC and 6FDA-SBC, especially for H2/N2and H2/CH4gas pairs. Furthermore, the CO2permeability of TB-MSBC is about 7.6 times higher than that of 6FDA-MSBC. The much-improved separation performance of TB-based polymers can be mainly attributed to the ineffective chain packing via the incorporation of the spriobichroman structure and a ladder-type bridged bicyclic TB unit.

The initial Li-ions nucleation on the basal plane of graphite anode with N-doped defects during the charge progress of lithium-ion battery was investigated theoretically by first-principle calculations using double-layered graphene (DLG) model. Based on the geometric structure optimization, the Li-ions are found to be accumulated on the top surface of N-doped DLG with single vacancy defect (SV-3N) in the near 2D structure. Also for the N-doped DLG with double vacancy defect (DV-4N), the Li-ions are deposit on its top surface, as well as could enter the interlayer space. The electronic analysis proves the ion character of Li layer. Therefore, the initial Li-ions nucleation on the basal plane of graphite with both N-doped SV and DV defects can be suppressed with different detailed mechanisms. The calculation of diffusion energy and lithiation potential shows that the Li-ions nucleation is inhibited via an adsorption-like and intercalation-like process on the DLG with SV-3N and DV-4N, respectively. Additionally, the calculated adsorption energy suggests that more Li atoms are adsorbed due to the presence of N, and thus the capacity of N doped graphite anode can be enhanced accordingly.

The effects of boron on the microstructure and intergranular corrosion behavior of UNS S31254 (S31254) austenitic stainless steels were investigated. The sensitivity to intergranular corrosion in the samples was determined by an altered double loop electrochemical potentiokinetic reactivation method. The microstructure characterization showed that the S31254 steels only precipitated sigma (s, Fe-Cr-Mo-Ni) phases during the aging process, but boron addition decreased the amount of s phase precipitation, reduced the size of the s phases, and promoted the formation of small Laves phases at the grain boundaries. The precipitated s phases lead to surrounding zones depleted of Cr and Mo, leading to intergranular corrosion. The S31254 alloy with added boron slows down the intergranular corrosion, due to microstructure manipulation at the grain boundaries.

Bacteria use quorum sensing (QS) systems to communicate with each other and regulate microbial group behavior, such as the secretion of virulence factors, including biofilm formation. In order to explore safe, edible agents, the potential of star anise (SA) as an anti-QS and antibiofilm agent and its possible application in milk safety were investigated. Staphylococcus aureus, SalmonellaTyphimurium, Pseudomonas aeruginosa,and biosensor strain Chromobacterium violaceumwere selected as test strains for QS, biofilm, and exopolysaccharide assays. The percent acidities and total plate counts were determined to evaluate the quality of biofilm-inoculated and noninoculated milk. The yield of SA extraction was 25.90% ± 0.2% (w/w). At sub-MIC, SA extract did not show any effect on bacterial growth. The production of violacein was inhibited by 89% by SA extract. The extract also inhibited the formation of biofilm by up to 87% in a dose-dependent manner. Inhibition rates of 70.45%, 42.82%, and 35.66% were found for exopolysaccharide production. The swarming motility of S. aureuswas reduced by about 95.9% by SA extract. Confocal laser scanning microscopy analysis confirmed that the development of biofilm architecture was hampered. It was found that SA extract could delay the spoilage of milk. In the endeavor to avoid drug resistance, pathogenesis, and resistance to biocides while improving food safety and avoiding health hazard issues arising from synthetic chemicals, SA extract could be used as a potential QS and biofilm inhibitor.

Magnesium (AZ31) alloy was employed as the carrier of mesoporous TiO 2 films catalyst. TiO 2 films were prepared by the liquid phase deposition (LPD) method. The films transform to anatase at 189°C. The anatase phase was certified by X-ray diffractometer (XRD). The surface of the films consisted of particles whose diameter was about 150 nm. There were protuberances and micropores on the particles and their size was about 10 nm. The thickness of the films was about 6 μm. The films can catalytically decompose the methylene blue under the irradiation of the visible light. The films sintered in the vacuum furnace have high photocatalysis activity compared with those sintered in the air atmosphere. The Mg and Al atoms can diffuse from the substrate to the films. The Mg2+ ionic can help to generate the cavity and the oxygen defect. The vacuum sintering condition can benefit formation of the oxygen defect. These defects enhanced the photocatalysis.

Cu2V2O7is an important material to improve low conductivity of Li4Ti5O12. Herein, Li4Ti5O12/Cu2V2O7with different Cu2V2O7ratios is successfully prepared by a liquid phase‐assisted dispersion method. The results show that the electrochemical properties of Li4Ti5O12are affected by the Cu2V2O7content incorporated in the composites. Among all obtained samples, Li4Ti5O12/0.05 Cu2V2O7reveals the best electrochemical performance and capacity retention rate, and its first cycle specific capacity is 246.3/197.2 mAh g−1when the current density is 30 mA g−1and it maintains values of 175.8/175 mAh g−1for 200 cycles between 1.0 and 3.0 V. The resulting Li4Ti5O12/0.05 Cu2V2O7composite also displays higher capacities at elevated current densities of 120 and 1200 mA g−1, with values always superior to those of the original Li4Ti5O12. The detailed electrode dynamics analysis illustrates that the introduced Cu2V2O7phase in the composites improves the cycle stability and lithium‐ion transfer rate of Li4Ti5O12. Through in situ X‐ray diffractometry (XRD) test analysis of the Li4Ti5O12/0.05 Cu2V2O7composite material, it is confirmed that the lithium storage mechanism is improved, where metallic Cu is formed in situ during each charge and discharge reaction process; thereby, the electronic conductivity of the composite material is improved and charge transfer resistance of the bulk material is reduced. Herein, Cu2V2O7is used as an additive to boost the electrochemical performance of Li4Ti5O12. Expectedly, the Li4Ti5O12/0.05 Cu2V2O7composites demonstrate high cycle capacity and high rate capability. In situ X‐ray diffractometry analysis verifies the enhanced lithium storage mechanism of Li4Ti5O12/0.05 Cu2V2O7composites due to in situ formation of metallic Cu during discharge/charge processes, which greatly improves the electronic conductivity of Li4Ti5O12.

Lactobionic acid (LBA) is a novel antibacterial agent that has attracted much interest in recent years. However, the study on the antibacterial effect of LBA on spoilage bacteria is rare. This study aims to investigate the antibacterial activity and mechanism of LBA on Shewanella balticaand Shewanella putrefaciens, which are the common spoilage microorganisms in chilled seafood. The results demonstrated that LBA was an effective bacteriostat against S. balticaand S. putrefaciens, with the minimum inhibitor concentration (MIC) of 8 mg/mL. Both the two Shewanellaspecies could be completely killed by LBA at 2 MIC. LBA damaged the cell membrane integrity and increased outer membrane permeability, causing the increase in protein leakage and conductivity, which was supported by the bacterial morphology observed with scanning electron microscopy. Besides, LBA could interact with the bacterial genome DNA, resulting in the dysfunction of cell function. Moreover, LBA exhibited an effectively inhibitory effect on slowing down microbial growth, melanosis and lipid oxidation rate in refrigerated shrimp. These results suggest that LBA would be a promising antibacterial compound used in seafood.

A new kind of functional graphene oxide with fine stability in water was fabricated by mixing graphene oxide (GO) and brilliant blue (BB) with a certain weight ratio. The adsorption performance of this mixture of BB and GO (BBGO) to polycyclic aromatic hydrocarbons (anthracenemethanol (AC) and fluoranthene (FL)) was investigated, and the results indicated BBGO possessed adsorption capacity of 1.676 mmol/g and removal efficiency of 72.7% as to AC and adsorption capacity of 2.212 mmol/g and removal efficiency of 93.2% as to FL. After adsorption, pH and temperature-sensitive coagulation (PTC) method was used to remove the AC/BBGO or FL/BBGO complex and proved to be an effective approach to flocculate the AC/BBGO or FL/BBGO complex into large flocs, which tended to be removed from the aqueous solution.

The rod-shaped and the tubular amorphous alloys Fe 36 Co 36 B 20 Si 4 Nb 4 were respectively prepared by copper mould sucking - casting method; composite materials with nano-crystalline distributed uniformly in the matrix of bulk amorphous alloy was achieved at different temperature and holding time to amorphous alloy Fe 36 Co 36 B 20 Si 4 Nb 4 for annealing treatment by the method of amorphous solid crystallisation. Their thermal stability, the characteristics of structure and the distribution situation of nano-crystalline were analysed and checked by X-ray diffraction (XRD), differential scanning calorimetry and transmission electronic microscopy (TEM).

On 30 June 2020, young scholars presented & discussed their work in a virtual forum, as a special session organized by The 15th International Conference on Waste Management and Technology (June 28–30), 2020 Beijing China. The forum convened researchers and attendees approaching innovative aspects of waste management from a variety of perspectives and disciplines. While their presentations spanned topics as broad as the stakeholder coordination and as specific technological approach for rapid carbonization of agricultural waste, several conceptual threads could be traced across them.

The effects of boron on the microstructure and intergranular corrosion behavior of UNS S31254 (S31254) austenitic stainless steels were investigated. The sensitivity to intergranular corrosion in the samples was determined by an altered double loop electrochemical potentiokinetic reactivation method. The microstructure characterization showed that the S31254 steels only precipitated sigma (σ, Fe-Cr-Mo-Ni) phases during the aging process, but boron addition decreased the amount of σ phase precipitation, reduced the size of the σ phases, and promoted the formation of small Laves phases at the grain boundaries. The precipitated σ phases lead to surrounding zones depleted of Cr and Mo, leading to intergranular corrosion. The S31254 alloy with added boron slows down the intergranular corrosion, due to microstructure manipulation at the grain boundaries.

The initial Li-ions nucleation on the basal plane of graphite anode with N-doped defects during the charge progress of lithium-ion battery was investigated theoretically by first-principle calculations using double-layered graphene (DLG) model. Based on the geometric structure optimization, the Li-ions are found to be accumulated on the top surface of N-doped DLG with single vacancy defect (SV-3N) in the near 2D structure. Also for the N-doped DLG with double vacancy defect (DV-4N), the Li-ions are deposit on its top surface, as well as could enter the interlayer space. The electronic analysis proves the ion character of Li layer. Therefore, the initial Li-ions nucleation on the basal plane of graphite with both N-doped SV and DV defects can be suppressed with different detailed mechanisms. The calculation of diffusion energy and lithiation potential shows that the Li-ions nucleation is inhibited via an adsorption-like and intercalation-like process on the DLG with SV-3N and DV-4N, respectively. Additionally, the calculated adsorption energy suggests that more Li atoms are adsorbed due to the presence of N, and thus the capacity of N doped graphite anode can be enhanced accordingly.