RSC Advances

Tang, Tongtong; Sun, Xing; Liu, Qin; Dong, Yuanhua; Xiang, Yuyong

doi: 10.1039/d0ra05452fpmid: 35515690

Bio-organic fertilizers based on biocontrol microorganisms have been widely applied to suppress soilborne diseases and improve crop yields. Studies on beneficial biocontrol agents have promoted the development of the bio-organic fertilizers in China. Our previous study demonstrated that a biocontrol agent, Erythrobacter sp. YH-07, can inhibit the growth of the plant pathogen Fusarium oxysporum. In the present study, we investigated the effects of this biocontrol agent on tomato wilt and used the illumina-based sequencing approach to characterize the variations in soil bacterial communities in a potted experiment. The aim of our study was to explore the potential correlation among bacterial communities, Fusarium wilt suppression, and soil properties after application of the biocontrol agent YH-07. The results showed that application of Erythrobacter sp. YH-07 effectively controlled outbreaks of tomato Fusarium wilt. The illumina MiSeq sequencing showed that Proteobacteria was the predominant phylum in the soil samples. Bacterial community composition and structure varied under different soil treatments, e.g., the relative abundance of Erythrobacter and Salinimicrobium was significantly increased in the YH treatment, and Acidobacteria were decreased in the YH treatment compared with the CK treatment. Additionally, the correlation results showed that the soil organic matter and available phosphorus and potassium were higher after YH-07 application, and they were positively correlated with bacterial community. The redundancy analysis showed Erythrobacter and Acidobacteria were the dominant genera after YH and CK treatments, respectively, and correlations with tomato Fusarium wilt incidence were negative and positive, respectively.

Khuenkaeo, Nattawut; MacQueen, Blake; Onsree, Thossaporn; Daiya, Sangu; Tippayawong, Nakorn; Lauterbach, Jochen

doi: 10.1039/d0ra06014cpmid: 35515664

Fast pyrolysis, in combination with torrefaction pretreatment, was used to convert tobacco residues to value-added bio-fuels and chemicals. Tobacco plant residues were torrefied at 220, 260, and 300 °C, before being pyrolyzed at 450, 500, 550, and 600 °C in a rotating blade ablative reactor under vacuum conditions to test the effects on product yields. With torrefaction, tobacco residues thermally decomposed 20–25% w/w at low temperatures. Torrefaction and pyrolysis temperatures were found to markedly affect pyrolytic product yields of bio-chars and bio-oils, while having no effect on gas-phase products. Bio-oil yields exhibited a direct relation with pyrolysis temperature and an inverse relation with torrefaction temperature. Bio-oils produced were separated into light and heavy oils and analyzed by GC-MS, and 1H and 13C NMR. Nicotine was found to be the main compound in the light and heavy oils along with several phenols and cresols in the heavy oil.

Wang, Qi; Zhang, Yifeng; Ren, Yuanyuan; Cheng, Weiwei; Bi, Yuge; Chen, Feng; Cheng, Ka-Wing

doi: 10.1039/d0ra05758dpmid: 35515679

Heterocyclic amines (HAs) are potent mutagens, which can form DNA adducts in various human tissues. There is increasing evidence that mutagenic HA formation and nutrition loss can occur concurrently in fish during vigorous heat treatment. Our study investigated the effects of five Allium spp. (garlic, onion, welsh onion, Chinese chive, and Mongolian leek) on reducing HA formation and improving nutritional quality of roasted cod (Gadus morhua). The results showed that cod patties pretreated with powders of the selected Allium spp. had significantly (P < 0.05) lower levels of HAs (82–92%, except garlic, 49%) than the control. The contents of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in the patties exhibited strong negative correlations with total antioxidant activity (−0.937), phenolic (−0.948), and lipophilic flavonoid (−0.933) contents, whereas the 2-amino-3,8 dimethylimidazo [4,5-f] quinoxaline (MeIQx) (made up only ∼0.7–3% of total HAs) contents exhibited significant positive correlations with these antioxidant parameters. In terms of nutrient composition change, Chinese chive and Mongolian leek were the most effective in preventing oxidative degradation of proteins and unsaturated fatty acids in roasted cod patties, which was translated into significantly higher contents of soluble proteins, essential amino acids, and polyunsaturated fatty acids. This has been the first report on the strong HA-formation inhibitory effect of Chinese chive and Mongolian leek. The dual beneficial functionality of these two Allium spp. may be utilized to reduce the intake of hazardous by-products while enhancing the nutritional and antioxidant properties of roasted cod and probably other protein-rich heat-processed foods.

Han, Guo-Cheng; Li, Huifang; Ferranco, Annaleizle; Tao Zhan, ; Cheng, Yunyun; Chen, Zhencheng; Xue, Mingyue; Feng, Xiao-Zhen; Kraatz, Heinz-Bernhard

doi: 10.1039/d0ra06942fpmid: 35515684

Several simple sensors were fabricated through a one-step method. By depositing electro-active compounds, such as β-cyclodextrins (β-CD), heme, dopamine (DA), or Fc-ECG, onto a screen-printed electrode (SPE), the successful simultaneous detection of nitrite (NO2−) and thiosulfate (S2O32−) ions was observed. Under optimal operating conditions, the notable electrocatalytic abilities of a Heme/SPE sensor were detected for the oxidation of NO2− and S2O32−, with remarkable peak potential differences, after characterization via SEM, CV, and DPV. Linear relationships were obtained in the ranges of 5.0–200.0 μmol L−1 and 1.0–100.0 μmol L−1 for the current response versus concentration of NO2− and S2O32−, respectively. The limits of detection were determined to be 1.67 and 0.33 μmol L−1 while the sensitivities of detection were noted to be 0.43 and 1.43 μA μM−1 cm−2, respectively. During the detection of NO2− and S2O32−, no interfering common ions were observed. Furthermore, average recoveries from 96.0 to 104.3% and a total R.S.D. of less than 3.1% were found for the detection of NO2− and S2O32− in pickled juice and tap water using the simple sensor. These results showed that rapid and precise measurements for actual application in NO2− and S2O32− detection could be conducted in food samples, indicating a potential use in food safety.

Labarrière, Luc; Moncomble, Aurélien; Cornard, Jean-Paul

doi: 10.1039/d0ra06833kpmid: 35515691

2′,3-Dihydroxyflavone (2′3HF) is a natural flavonol that has barely ever been studied, however the scarce studies of its physico-chemical properties have highlighted its atypical behaviour. We present a structural and spectral study of 2′3HF, performed using UV-visible absorption and fluorescence spectroscopies, coupled with DFT and TD-DFT calculations. Although its structure is close to that of 3-hydroxyflavone, 2′3HF shows a much lower pKa value. We show that the origin of this particularity is the substitution by a hydroxyl group on position 2′, that induces a stronger inter-ring interaction weakening the bonding of the proton at position 3. The main absorption band of the is red-shifted upon deprotonation. The remaining proton is highly bonded in between oxygen atoms 3 and 2′, making the second deprotonation unattainable in methanol. The neutral form can undergo an excited-state intramolecular proton transfer to emit dual fluorescence by the normal and tautomer forms. We suggested five geometries to be the sources of the emission bands, and showed that the energy barriers to interconversions were almost null. The anion is also fluorescent. The Stokes shifts for the neutral normal and anion species are extremely high, that can be explained by the conformational rearrangement, as the species go from twisted in the ground-state, to planar in the excited-state. Finally, another emission band is evidenced when exciting in the vicinity of the absorption maximum of the anion species in acidic medium. We suggest an aggregate with the solvent to be the origin of the emission.

Koroleva, Maria S.; Tracey, Chantal; Sidunets, Yuri A.; Torlopov, Mikhail A.; Mikhaylov, Vasily I.; Krivoshapkin, Pavel V.; Martakov, Ilia S.; Krivoshapkina, Elena F.

doi: 10.1039/d0ra07300hpmid: 35515643

Both cellulose nanocrystals and gold nanoparticles show immense potential for biological and chemical applications. Gold nanoparticles, which tend to aggregate, are hybridized with cellulose nanocrystals to form stable inorganic–organic hybrids in which nanocellulose acts as a green supporting material for the catalytically active gold nanoparticles. A green synthesis approach was taken, and hydrothermal treatment was used to reduce electrostatic repulsion between the gold nanoparticles and the cellulose nanocrystals to promote heteroaggregation instead of homoaggregation. AFM analysis showed hybrid films to be hygroscopic, suggesting that they would respond to changes in humidity. Laser diffraction and fluorescence quenching were used to determine how hybrid films respond to changes in humidity. Hybrid films were found to respond to changes in humidity quickly, reversibly, and autonomously, making them ideal for use as or in a humidity sensor. Gold nanoparticles were shown to enhance the hybrid response to ambient moisture, causing them to show a linear dependence on changes in humidity, making the hybrid controllable, highly sensitive, and a viable prospective material for humidity sensing applications.

Varas, Lautaro R.; Fantuzzi, Felipe; Coutinho, Lúcia Helena; Bernini, Rafael B.; Nascimento, Marco Antonio Chaer; de Souza, G. G. B.

doi: 10.1039/d0ra05979jpmid: 35515687

Disulfide bonds (–S–S–) are commonly present in biomolecules and have also been detected in astrophysical environments. In this work, the stability of the disulfide bond towards double ionization is investigated using quantum chemical calculations and photoelectron photoion photoion coincidence (PEPIPICO) spectroscopy measurements on the prototype dimethyl disulfide (CH3SSCH3, DMDS) molecule. The experiments were performed using high energy synchrotron radiation photons before (2465.0 eV) and at (2470.9 eV) the first sigma resonance around the S 1s edge. We applied the multivariate normal distribution analysis to identify the most plausible ionic fragmentation mechanisms from the doubly ionized DMDS. By mapping the minimum energy structures on the dicationic C2H6S22+ potential energy surface, we show that disulfide bonds are only present in high-lying isomers, in contrast to their analogous neutral systems. Our results also indicate that the number of fragment ions containing a disulfide bond for both photon energies is negligible. Taken together, our results reveal that the disulfide bond is severely damaged as a consequence of sulfur core–shell ionization processes, due to the lowering of its thermodynamic stability in multiply-charged systems.

Chen, Xinyu; Qin, Yanqing; Shi, Diwei; Guo, Yaolin; Bu, Moran; Yan, Tao; Song, Jiexi; Liu, Guoquan; Zhang, Yiming; Du, Shiyu

doi: 10.1039/d0ra07374apmid: 35515670

U3Si2 has been tested as a new type of nuclear fuel, and Al has been proven to improve its oxidation resistance. However, there is no research on its anisotropic mechanical and thermal properties. The mechanical and thermal properties of Al-alloyed U3Si2 nuclear fuel are calculated on the basis of first principles. Through the phonon dispersion curves, two kinetic stable structures sub-U3Si1.5Al0.5 and sub-U2.5Si2Al0.5(I) are screened out. It is found that the toughness of these two compounds after alloying are significantly improved compared to U3Si2. The three-dimensional Young's modulus shows that, the sub-U3Si1.5Al0.5 formed by Al alloying in U3Si2 maintains a higher mechanical isotropy, while sub-U2.5Si2Al0.5(I) shows higher mechanical anisotropy, which is consistent with the value of Au. The calculation result shows that the lattice thermal conductivity of sub-U3Si1.5Al0.5 and sub-U2.5Si2Al0.5(I) after alloying exhibits high isotropy as the temperature increases.

Bharti, Abha; Natarajan, Rajalakshmi

doi: 10.1039/d0ra06640kpmid: 35515650

A simple and economical route using an environmental friendly solvent is reported for recovering catalyst from the end-of-life membrane electrode assembly. This precious component is recovered in the form of Pt/C and ionomer powder. The catalyst exhibited an electrochemical surface area of 42 m2 g−1 and remarkable stability, showcasing its potential for second life applications.

Zhou, X. W.

doi: 10.1039/d0ra07227cpmid: 35515678

In the past, experimentally observed dislocations were often interpreted using an isolated dislocation assumption because the effect of background dislocation density was difficult to evaluate. Contrarily, dislocations caused by atomistic simulations under periodic boundary conditions can be better interpreted because linear elastic theory has been developed to address the effect of periodic dislocation array in the literature. However, this elastic theory has been developed only for perfect dislocations, but not for dissociated dislocations. The periodic boundary conditions may significantly change the dissociation energy of dislocations and stacking fault width, which in turn, change the deformation phenomena observed in simulations. To enable materials scientists to understand the dislocation behavior under the periodic boundary conditions, we use isotropic elastic theory to analyze the thermodynamics of dissociated periodic dislocations with an arbitrary dislocation character angle. Analytical expressions for force, stacking fault width, and energies are presented in the study. Results obtained from the periodic dislocation array were compared with those obtained from isolated dislocations to shed light on the interpretation of experimentally observed and simulated dislocations.