Search

Cocrystals are assemblies of more than one type of molecule stabilized through noncovalent interactions. They are promising materials for improved drug formulation in which the stability, solubility, or biocompatibility of the active pharmaceutical ingredient (API) is improved by including a coformer. In this work, a range of density functional theory (DFT) and density functional tight binding (DFTB) models are systematically compared for their ability to predict the lattice enthalpy of a broad range of existing pharmaceutically relevant cocrystals. These range from cocrystals containing model compounds 4,4′‐bipyridine and oxalic acid to those with the well benchmarked APIs of aspirin and paracetamol, all tested with a large set of alternative coformers. For simple cocrystals, there is a general consensus in lattice enthalpy calculated by the different DFT models. For the cocrystals with API coformers the cocrystals, enthalpy predictions depend strongly on the DFT model. The significantly lighter DFTB models predict unrealistic values of lattice enthalpy even for simple cocrystals. [ABSTRACT FROM AUTHOR]

We explored the potential value of the alcohol dehydrogenase (ADH) inhibitor isovaleramide (ISO) in the treatment of acute ethylene glycol (EG) poisoning‐induced acute kidney injury. Sprague–Dawley rats were divided into the control, EG, EG + ISO (10 mg/kg) and EG + ISO (20 mg/kg) groups. It is found that ISO intervention significantly reduced the ADH activity in liver tissue by using visible spectrophotometry, inhibited the in vivo metabolism of EG by using gas chromatography, lowered the levels of toxic metabolites glycolic acid and oxalic acid by using high‐performance liquid chromatography and decreased the expression of kidney injury markers serum creatinine (sCr), KIM‐1, neutrophil gelatinase‐associated lipocalin (NGAL) and liver fatty acid‐binding protein (L‐FABP) by ELISA. Additionally, Western blotting results showed that ISO down‐regulated the expression of apoptotic factors Bax and cleaved caspase‐3 in the kidneys and upregulated the expression of antiapoptotic factor Bcl‐2. Pizzolato staining and polarized light microscopy results revealed the reduced deposition of calcium oxalate crystals in the kidney tubules. Using haematoxylin and eosin (H&E), periodic acid‐Schiff (PAS) and Masson staining, we found attenuated kidney tissue pathological injury. Finally, ISO significantly reduced the mortality rate. In conclusion, ISO has the potential to be a valuable drug for the treatment of EG poisoning‐induced acute kidney injury. [ABSTRACT FROM AUTHOR]

Choline chloride (ChCl) based binary and ternary deep eutectic solvents (DES) were evaluated for methylene green electropolymerization with oxalic acid (OA) and ethylene glycol (EG) as hydrogen bond donors. Binary DES ChCl : OA in molar ratios 1 : 1 and 2 : 1 and ChCl : EG 1 : 2 and ternary DES (tDES) in different molar ratios and percentages of water were evaluated. The highest polymer growth was in ChCl : OA : EG‐tDES with 13% added water, that had a lower viscosity and higher ionic conductivity when associated with HCl as dopant. This enhanced the formation of more cation radicals and, consequently, more polymer formation. The PMG/MWCNT/GCE‐tDES sensor was successfully applied to the simultaneous determination of 5‐aminosalicylic acid (5‐ASA) and acetaminophen (APAP) by differential pulse voltammetry in the concentration range 1 μM–200 μM, with detection limits of 0.37 μM and 0.49 μM for 5‐ASA and APAP, respectively. The sensor demonstrated good repeatability, reproducibility and stability, and was successfully applied in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Strongly oxidizing ·OH can non‐selectively degrade various organic pollutants, but how to selectively generate ·OH is a great challenge. In this study, the directed generation of ·OH was achieved based on Ni–Ca metastable–nonmetastable bimetallic sites, Ni2+/Ni3+ valence cycling provided electrons for ·OH generation induced by the non‐variable Ca‐based sites, which constructed a nearly 100% selective generation pathway of ·OH (O3 → HO3/HO2 → OH). The antibiotic pefloxacin could be completely removed in 15 min, and the COD removal efficiency for other hard‐to‐degrade pollutants such as oxalic acid and chlorobenzoic acid could reach more than 90%. Ni doping significantly increased the oxygen vacancy and Lewis acid content, and DFT calculations showed that Ni–Ca dual‐site had a lower reaction energy barrier and the complexed hydroxyl radical intermediate *OO had a higher spin density (−0.6), which was more favorable for the generation of ·OH. Therefore, this study provides new ideas for efficient treatment of actual wastewater. [ABSTRACT FROM AUTHOR]

In this study, the cathode active material was first separated from the aluminum foil through a heat treatment at 500 °C. The separated cathode active material was calcined at a temperature of 1000 °C to remove completely carbon particles generated from the organic adhesive during heat treatment. Then, Co, Mn, and Ni were recovered from the cathode active material using lactic acid and oxalic acid as leaching and precipitating reagents. The lactic acid showed almost similar metal leaching effects from cathode active material compared to sulfuric acid, hydrochloric acid, and nitric acid. The optimal metal leaching efficiency by lactic acid was obtained when 30 g of the cathode active material was added to the 2 N lactic acid solution. At these conditions, the leaching efficiencies of Li, Mn, Co, and Ni were 90.4%, 89.2%, 92.2%, and 91.8%, respectively. Subsequently, when 5 g of oxalic acid was added to the lactic leachate of 2 N, a phenomenon in which all metals were precipitated was observed. Based on this result, the optimal condition for precipitating the leached metals using oxalic acid was oxalic acid/cathode active material = 1:7 (w/w %). Through XRD and EDX analysis, the precipitate was identified as a polynuclear crystalline material (NiCoMnC2O4·2H2O) in which the three components of Mn, Co, and Ni oxalates were mixed with approximately 7:4:10 in integer ratio of weight. The produced precipitate can be recycled as a raw material of cathode active material through simple heat treatment. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The stability of organic radicals in ambient condition is important for their practical application. During the development of organic radical chemistry, the electron‐withdrawing and steric hindrance groups are usually introduced to improve the stability of radicals via reducing the reactivity of radicals with oxygen in air. Herein, the electron‐withdrawing carbonyl groups are introduced to construct a planar aromatic oxalic acid radical (IDF‐O8) with two‐dimensional electron spin pan structure. Interestingly, IDF‐O8 exhibited a low optical bandgap of 0.91 eV in film, however, the multiple quinone resonance structures between electron‐withdrawing ketone and phenol radicals contribute to the high stability of open‐shell radical IDF‐O8 without protection of large steric hindrance groups. Under the irradiation of 808 nm (1.2 W·cm–2), IDF‐O8 reaches 147 °C in powder state. This work provides an efficient synthesis route for the open‐shell electron spin pan system, which is different from the famous fullerene, carbon nanotube and graphene. The electron spin pan can be extended to spin tube or spin sphere system based on the design strategy of aromatic inorganic acid radicals in future. [ABSTRACT FROM AUTHOR]

A novel and efficient protocol for the microwave‐assisted synthesis of diversely substituted 2,2′‐bisbenzimidazol‐5,6′‐dicarboxylic acid (BIMCA) from the reaction of 3,4‐diaminobenzoic acid with oxalic acid has been developed, which proceeds through sequential nucleophilic addition and electrophilic substitution in accordance with the Philips method. The synthetic utility of this strategy was demonstrated by the concise, one‐pot synthesis of (BIMCA) and metal complexes. (BIMCA) with a [{Fe(salen)}2O] Schiff base ligand complex and new benzimidazole coordination compounds with double oxygen [(BIMCA){Fe(salen)}2] ligand complexes were obtained. The resulting [(BIMCA){Fe(salen)}2] ligand complex was then synthesized from Co(CH3COO)2.4H2O, Ni(CH3COO)2.4H2O and Cu(CH3COO)2.H2O heteronuclear complexes. The condensations proceed with good yield to give products that, in certain instances, are not readily attainable by conventional condensation techniques. The structures of the compounds were identified by Fourier‐transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), elemental analysis and magnetic susceptibility. The mutagenic potential of the synthesized chemicals was evaluated by the Ames test towards mutant Salmonella typhimurium strains TA98 and TA100. It was recorded that these chemicals had no mutagenic action. Also, antimicrobial activities were screened by broth microdilution test. It was seen that the minimum inhibitory concentration (MIC) against Klebsiella pneumoniae, Staphylococcus aureus and Staphylococcus epidermidis was 0.195 mg/mL, followed by a MIC value of 0.390 mg/mL against Escherichia coli and Salmonella typhimurium. [(BIMCA){Fe(salen)}2Co(II)] demonstrated significant antimicrobial activity against Proteus mirabilis and Staphylococcus aureus, with an MIC of 0.195 mg/mL, followed by an MIC of 0.390 mg/mL against Pseudomonas aeruginosa, K. pneumonia and Salmonella typhimurium. The antioxidant properties were examined using various chemical assays, and [(BIMCA){Fe(salen)}2O] and (BIMCA) exhibited greater 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging ability, when compared with other compounds. Enzyme inhibitory effects were tested against acetylcholinesterase (AChE), amylase, butyrylcholinesterase (BChE) and tyrosinase. [(BIMCA){Fe(salen)}2Cu(II)] displayed the best AChE (IC50 0.51 mg/mL), BChE (IC50 0.51 mg/mL) and tyrosinase (IC50 1.52 mg/mL) inhibitory effects. Furthermore, molecular docking calculations were performed to gain insights into the interaction between [(BIMCA){Fe(salen)}2] and AChE, and between [(BIMCA){Fe(salen)}2Cu(II)] and amylase. Both compounds showed the potential inhibition of the protein targets. [ABSTRACT FROM AUTHOR]

Dicarboxylic acids (DCAs) are major players in the formation of secondary organic aerosols (SOAs) and climate change. DCAs have potential impact on human health and environmental issues ranging from local scale to global scale participate mainly in the cloud condensation. In this context, oxalic acid (OA) and malonic acid (MA) are the most dominant DCAs in the atmosphere. A full atmospheric degradation mechanism of OA and MA with the most reactive tropospheric oxidants, namely, OH, Cl and NO3 radicals, were studied using M06‐2X, ωB97XD/cc‐pVTZ and 6‐311++G(2df,2p) level of theories. To evaluate the atmospheric influence, this study enables us to deep investigation of fate of OA and MA with respect to the mentioned radicals and their subsequent secondary reactions. The latter result in the formation of carbon dioxide (CO2), formic acid (HCOOH), which contributes to the formation of SOA and climate change. The reaction mechanism in this study was initiated through H‐abstraction reaction, followed by dehydrogenation and decarboxylation reaction of both DCAs. The rate coefficients of OA, MA with OH, Cl and NO3 radicals are determined theoretically using variational transition state theory (VTST) with Eckart tunnelling method in the temperature range of 278–1000 K. At 298 K, the rate coefficient of OA with OH, Cl and NO3 are 2.48 × 10−15, 2.37 × 10−20, 6.16 × 10−23 in cm3 molecule−1 s−1, whereas MA with OH, Cl and NO3 are 9.76 × 10−14, 1.01 × 10−12 and 5.89 × 10−18 in cm3 molecule−1 s−1, respectively. Our present results shed light on the atmospheric implications of two DCAs and provide the significant insight for the atmospheric pathways. [ABSTRACT FROM AUTHOR]

BACKGROUND: The excessive salt intake associated with Douchi has become a topic of controversy. Addressing this concern and enhancing its market competitiveness necessitates the application of salt reduction fermentation in Douchi. Therefore, to promote the application of salt reduction fermentation in Douchi, a comprehensive study was undertaken aiming to investigate the differences in biogenic amines, volatile compounds and non‐volatile compounds in Douchi with varying salt content. RESULTS: The findings unequivocally demonstrate that salt hampers the formation of metabolites in Douchi. As the salt content increased, there was a significant decrease (P < 0.05) in the levels of total acid, amino‐type nitrogen and free amino acids in Douchi. Notably, when the salt content exceeded 80 g kg−1, there was a substantial reduction (P < 0.05) in putrescine, lactic acid and malic acid levels. Similarly, when the salt content surpassed 40 g kg−1, β‐phenethylamine and oxalic acid levels exhibited a significant decline (P < 0.05). Furthermore, the results of E‐nose and principal component analysis based on headspace solid phase microextraction gas chromatography–mass spectrometry revealed notable discrepancies in the volatile compound content between Douchi samples with relatively low salt content (40 and 80 g kg−1) and those with relatively high salt content (120, 160 and 200 g kg−1) (P < 0.05). By employing partial least squares discriminant analysis, eight distinct volatile compounds, including o‐xylene, benzaldehyde and 1‐octen‐one, were identified. These compounds exhibited higher concentrations in Douchi samples with relatively low salt content (40 and 80 g kg−1). The sensory results showed that Douchi samples with lower salt content exhibited higher scores in the soy sauce‐like and Douchi aroma attributes. CONCLUSION: In conclusion, this study significantly enhances our understanding of the impact of salt on metabolites in Douchi and provides invaluable insights for the development of salt reduction fermentation in this context. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI)) has attracted great considerations due to their high toxicity, teratogenicity, and carcinogenicity. In this study, four Zr‐MOFs were synthesized and used to comparative study their catalytic performances of oxalic acid (OA) for Cr(VI) removal. Results showed that the removal efficiency for Cr(VI) was reached 65.91%, 78.64%, 53.58%, and 96.32% by MOF‐525, MOF‐525(Co), MOF‐525(Zn), and MOF‐525(Fe) in the presence of OA when the initial Cr(VI) concentration was 100 mg·L−1, respectively. The single‐factor experiments for further improving the Cr(VI) removal by MOF‐525(Fe)/OA demonstrated that the optimal conditions were OA dosage of 790 mg·L−1, and MOF‐525(Fe) dosage of 500 mg·L−1 and pH of 2.0, and the MOF‐525(Fe)/OA system could be used to treat Cr(VI)‐containing wastewater at concentrations below 50 mg·L−1. Ionic strength studies indicated that Na+, K+, Mg2+, Cl−, and SO42− had little effect on the catalytic reduction of Cr(VI), while high concentrations of Ca2+ (0.10 and 0.25 mol·L−1), NO3− (0.25 mol·L−1), and PO43− (0.25 mol·L−1) had significant inhibition effects. The reusability experiments showed that the stability of MOF‐525(Fe) was excellent, and it could be used for potential applications. Based on the results of Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and Electron Paramagnetic Resonance spectrometer (EPR), the possible reduction mechanism of Cr(VI) by MOF‐525(Fe)/OA system was proposed as follows: The complexation of OA with Fe3+ was first complexed to produce Fe2+ and CO2•−, then Cr(VI) was combined with Zr–O and Fe–O clusters in MOF‐525(Fe) to obtain activation energy, and the reduction ability was enhanced at the same time; finally, Cr(VI) obtained electrons from CO2•− and was sequentially reduced as Cr(V) and Cr(III). [ABSTRACT FROM AUTHOR]

Fire and mechanical performances of a bio‐based flax/furan resin composite are evaluated and, in order to assess their commercial potential, compared with those of conventional carbon/glass fiber‐reinforced composites. Fire retardant (FR) variants of flax/furan were obtained by adding FRs to the resin and using (i) flax or (ii) FR‐treated flax fabrics. With (i), the fire hazard of the composite could be reduced to minimum, without detrimental effect on the mechanical properties. However, use of FR‐flax fabric (ii) led to impairment of mechanical properties. This indicated that for optimized fire and mechanical properties, use of a FR in the resin matrix suffices; there is no advantage in using a FR‐treated flax fabric. Natural aging of the samples for 10 years followed by water aging indicated that water absorption in flax/furan composites was much higher than in comparable carbon/epoxy composites. While there was evidence of released acidic components such as acetic acid, oxalic acid, and so forth, in flax/furan composites, mainly from oxidative degradation of furan resin, there was no evidence of leaching of FR additives from the matrix. However, FR treatment of flax fabric affected the fiber–matrix interfacial adhesion, leading to considerable water absorption during aging and disintegration of the reinforcement. Highlights: Furan resins are naturally fire retardant, burn only under forced combustion.FR flax/furan composites obtained by adding FRs to the resin or the flax fabric.FR treatment of the flax impairs mechanical properties and water tolerance.FRs in the resin neither affect mechanical properties nor leach out in water. [ABSTRACT FROM AUTHOR]

This study investigated the catalytic CO2 methanation using nickel oxide (NiO) nanoparticles and nickel oxalate (NiC2O4) as catalysts. The NiC2O4 precursor was synthesized through a chemical precipitation reaction between nickel (II) nitrate hexahydrate (Ni(NO3)2.6H2O) and oxalic acid (H2C2O4.2H2O). Nickel oxide (NiO) nanoparticles were synthesized through thermal decomposition of NiC2O4 precursor at 450 °C in air. The samples were characterized by XRD, FTIR, BET, SEM, and EDX. The XRD and FTIR analyses revealed that the NiO nanoparticles were well‐crystallized having size 17.30 nm. The BET analysis of the NiO sample revealed mesoporous NiO nanoparticles with a specific surface area (SBET) of 29.08 m2/g and a narrow distribution of pore sizes. The catalytic performance of NiO and NiC2O4 catalysts studied for the CO2 methanation in tubular packed bed reactor at 150–550 °C and 1 atm. The reduced NiO nanoparticles exhibited more catalytic activity than the decomposed NiC2O4 catalyst. At 380 °C, 1 atm, and gas hourly space velocity (GHSV) of 9000 mL g−1 h−1, the reduced NiO nanoparticle catalyst showed high catalytic activity, with a maximum CO2 conversion of 85.54 %, 99 % CH4 selectivity, and 84.69 % CH4 yield. Furthermore, the NiO nanoparticle catalyst demonstrated excellent stability after 12 h of streaming at 380 °C. [ABSTRACT FROM AUTHOR]

Analytical methods with wide field range and high spatial resolution are required to observe the distribution of the crystal structure in micro‐regions undergoing macroscopic chemical reactions. A recent X‐ray diffraction (XRD) imaging method combines XRD with an X‐ray optical device such as a glass polycapillary consisting of a bundle of numerous monocapillaries. The former provides the crystal structure, while the latter controls the shape of the incident or diffracted X‐rays and retains the positional information of the sample. Although reducing the monocapillary pore size should improve the spatial resolution, manufacturing technology challenges must be overcome. Here, an anodic aluminium oxide (AAO) film, which forms self‐ordered porous nanostructures by anodic oxidation in an electrolyte, is applied as an X‐ray optical device. The AAO film (pore diameter: 110 nm; size of the disc: 11 mm; and thickness: 620 µm) was fabricated by anodization in a mixture of oxalic acid and ethylene glycol. The film was incorporated into a laboratory XRD instrument. Compared with using a glass polycapillary alone, using a combination of a glass polycapillary and the AAO film improved the spatial resolution of the XRD imaging method by 40%. This XRD imaging method should not only provide practical analysis in a laboratory environment but also support various observations of the crystal structure distribution. [ABSTRACT FROM AUTHOR]

Aliphatic‐aromatic copolyesters offer a promising solution to mitigate plastic pollution, but high content of aliphatic units (>40 %) often suffer from diminished comprehensive performances. Poly(butylene oxalate‐co‐furandicarboxylate) (PBOF) copolyesters were synthesized by precisely controlling the oxalic acid content from 10 % to 60 %. Compared with commercial PBAT, the barrier properties of PBOF for H2O and O2 increased by more than 6 and 26 times, respectively. The introduction of the oxalic acid units allowed the water contact angle to be reduced from 82.5° to 62.9°. Superior hydrophilicity gave PBOF an excellent degradation performance within a 35‐day hydrolysis. Interestingly, PBO20F and PBO30F also displayed obvious decrease of molecular weight during hydrolysis, with elastic modulus >1 GPa and tensile strength between 35–54 MPa. PBOF achieved the highest hydrolysis rates among the reported PBF‐based copolyesters. The hydrolytic mechanism was further explored based on Fukui function analysis and density functional theory (DFT) calculation. Noncovalent analysis indicated that the water molecules formed hydrogen bonding interaction with adjacent ester groups and thus improved the reactivity of carbonyl carbon. PBOF not only meet the requirements of the high‐performance packaging market but can quickly degrade after the end of their usage cycles, providing a new choice for green and environmental protection. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pectin from Ficus carica Linn. (fig) peels is a valuable and recyclable constituent that may bring huge economic benefits. To maximize the utilization of this resource, deep eutectic solvent (DES)‐assisted extraction was applied to extract pectin from fig peels, and the extraction process was optimized with response surface methodology. RESULTS: When DES (choline chloride/oxalic acid = 1:1) content was 168.1 g kg−1, extraction temperature was 79.8 °C, liquid–solid ratio was 23.3 mL g−1, and extraction time was 120 min, the maximum yield of 239.6 g kg−1 was obtained, which was almost twice the extraction of hot water. DES‐extracted fig peel pectin (D‐FP) exhibited better nature than hot water‐extracted fig peel pectin (W‐FP) in terms of uronic acid content, particle size distribution, and solubility, but lower molecular weight and esterification degree. D‐FP and W‐FP had similar infrared spectra and thermodynamic peaks but differed in monosaccharide compositions. D‐FP also showed good antioxidant capacities and exhibited better functional activities than W‐FP. CONCLUSION: These results indicated that D‐FP was of promising quality being utilized in food or medical industries and the optimal DES‐assisted extraction method might be applied as a sustainable process for the effective extraction of bioactive pectin from fig peels with the excellence of low equipment requirements and simple operation. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The synthesis of enantiomerically pure tertiary alcohols is an important issue in organic synthesis of a range of pharmaceuticals including molecules such as the anti‐HIV drug Efavirenz. A conceptually elegant approach to such enantiomers is the dynamic kinetic resolution of racemic tertiary alcohols, which, however, requires efficient racemization strategies. The racemization of tertiary alcohols is particularly challenging due to various side reactions that can occur because of their high tendency for elimination reactions. In the last few years, several complementary catalytic concepts for racemization of tertiary alcohols have been developed, characterized by efficient racemization and suppression of unwanted side‐reactions. Besides resins bearing sulfonic acid moieties and a combination of boronic acid and oxalic acid as heterogeneous and homogeneous Brønsted‐acids, respectively, immobilized oxovanadium and piperidine turned out to be useful catalysts. The latter two catalysts, which have already been applied to different types of substrates, also have proven good compatibility with lipase, thus leading to the first two examples of chemoenzymatic dynamic kinetic resolution of tertiary alcohols. In this review, the difficulties in racemizing tertiary alcohols are specifically described, and the recently developed complementary concepts to overcome these hurdles are summarized. [ABSTRACT FROM AUTHOR]

The economic advantages of H2SO4 make it the acid of choice for the hydrometallurgical treatment of waste lithium-ion batteries (LIBs). However, to facilitate the full dissolution of the higher valency metal oxides present in the cathode black mass, a suitable reducing agent is required. Herein, the application of industrial black liquor (BL) obtained from the Kraft pulping for papermaking is investigated as a renewable reducing agent for the enhanced leaching of transition metals from LIB powder with H2SO4. The addition of acidified BL to H2SO4 significantly improved the leaching efficiency for a range of LIB cathode chemistries, with the strongest effect observed for manganese-rich active material. Focusing on NMC111 (LiMnxCoyNizO2) material, a linear correlation between the BL concentration and the leaching yield of Mn was obtained, with the best overall leaching efficiencies being achieved for 2.0 molL-1 H2SO4 and 50 vol% of BL at 353 K. A quasi-total degradation of oxygenated and aromatic groups from the BL during NMC111 dissolution was observed after leaching, suggesting that these chemical groups are essential for LIB reduction. Finally, the leached transition metals could be easily recovered by pH adjustment and oxalic acid addition, closing the resource loop and fostering resource efficiency. [ABSTRACT FROM AUTHOR]

Artificial tongues have attracted increasing attention for the perception abilities of five basic tastes. However, simple and versatile identification of different tastes is a formidable challenge for bionic taste sensor. Enriching photoluminescence mechanisms to improve possibilities of multiple optical responses is conducive to simplify the sensor array. Herein, a single sensor Tb@MCATMA (Tb@1) is developed displaying dual‐emissions of both green fluorescence and deep‐blue phosphorescence by ternary co‐assembly of Tb3+, trimesic acid (TMA) and a 2D hydrogen‐bonded organic framework of melamine and cyanuric acid, MCA HOF. This sensor is capable of imitating the human gustatory system to identify and discriminate umami (disodium 5′‐inosinate and disodium 5′‐guanylate), sour (citric acid and oxalic acid) and bitter (2‐furaldehyde and 5‐hydroxymethylfurfural) substances through the diverse photoresponsive modes. Upon excitation wavelength as additional variable, the sensor can further collect the individual "fingerprint information" of six analytes related to tastes and quantitatively detect them with high accuracy. Moreover, the sensing mechanism of each analyte is explored in detail and substantiate that the uniform photoresponsive modes elicited by distinct analytes stem from the shared sensing mechanism. This work provides a facile and powerful sensor platform for taste perception to develop artificial photoresponsive tongue applicable to bionic gustatory system. [ABSTRACT FROM AUTHOR]

We evidence the ferroelectricity of two isostructural magnetic coordination networks obtained from a chiral imidazolium dicarboxylate salt ((S, S)‐1,3‐bis(1‐carboxylethyl)imidazolium or [HL*]) and Gd3+ or Dy3+ ions in presence of oxalic acid (H2ox). The two compounds exhibit a chiral structure P1 and ferroelectric properties. The crystallographic study shows that the Dy based‐compound is isostructural to the Gd analog. The non‐centrosymmetry of the two samples was further checked by means of nonlinear optical spectroscopy. The room temperature ferroelectric character of the compounds has been investigated through by an original method, derived from that used for thin films, made possible by preparing the sample as thin slices of resin containing inclusions of the coordination compounds. [ABSTRACT FROM AUTHOR]

Gummy stem blight (GSB), a widespread disease causing great loss to cucurbit production, has become a major threat to melon cultivation. However, the melon–GSB interaction remains largely unknown. Here, full‐length transcriptome and widely targeted metabolome were used to investigate the defence responses of resistant (PI511089) and susceptible (Payzawat) melon accessions to GSB pathogen infection at 24 h. The biosynthesis of secondary metabolites and MAPK signalling pathway were specifically enriched for differentially expressed genes in PI511890, while carbohydrate metabolism and amino acid metabolism were specifically enriched in Payzawat. More than 1000 novel genes were identified and MAPK signalling pathway was specifically enriched for them in PI511890. There were 11 793 alternative splicing events involving in the defence response to GSB. Totally, 910 metabolites were identified in Payzawat and PI511890, and flavonoids were the dominant metabolites. Integrated full‐length transcriptome and metabolome analysis showed eriodictyol and oxalic acid were the potential marker metabolites for GSB resistance in melon. Moreover, posttranscription regulation was widely involved in the defence response of melon to GSB pathogen infection. These results not only improve our understanding on the interaction between melon and GSB, but also facilitate the genetic improvement of melon with GSB resistance. Summary statement: The early defence responses of resistant and susceptible melon (Cucumis melo L.) accessions to gummy stem blight infection caused by Stagonosporopsis cucurbitacearum were investigated and compared using the full‐length transcriptome, widely targeted metabolome and histochemical staining methods. [ABSTRACT FROM AUTHOR]

Catalytic carbonylation has gained a lot of interest over the past 20 years. It produced various pharmaceuticals, agrochemicals, and intermediates that can made through this process. The carbonylation process is the most straightforward method to insert CO into any organic substrate using a simple carbonyl source, i. e., CO gas. Apart from gaseous CO, many techniques have devised for producing CO in situ using surrogates such as HCOOH, DMF, Formic acid, Phenyl Formate, Oxalic acid, and Chloroform. Several carbonylation methods, such as aminocarbonylation, alkoxycarbonylation, double carbonylation, and oxidative carbonylation, provide viable and appealing substitutes for conventional synthetic methods on a commercial or laboratory scale. Many recent studies focus on catalyst‐product separation, catalyst recoverability, and reusability in these reactions. Therefore, advancements in using different approaches, such as supported liquid phase catalysis and biphasic catalysis, to anchor homogeneous catalysts are becoming increasingly important. These carbonylation methods are easy to use, cost‐effective, and do not require ligands. They also produce excellent yields of the products necessary. Using phosphine ligands has drawbacks, including high work‐up costs, laborious work‐up techniques, and sensitivity to air and moisture. Several phosphine‐free carbonylation pathways offer affordable and straightforward ways to accomplish these changes without phosphine ligands. This review summarizes the synthetic application of homogeneous and immobilized catalysts in producing carboxylic acid derivatives and heterocycles that have medicinal properties. [ABSTRACT FROM AUTHOR]

The recovery of valuable metals from spent lithium‐ion batteries using deep eutectic solvents (DESs) is an environmentally and economically beneficial process. In this study, a method has been developed for recovering LiNi0.33Co0.33Mn0.33O2. Our process operates under mild conditions and with a little oxalic acid as a reducing agent, dissolving lithium, cobalt, manganese, and nickel completely utilizing a DES that is composed of tetrabutylammonium chloride and of monochloroacetic acid. Lithium and nickel were selectively precipitated using oxalic acid. Cobalt and manganese were precipitated as oxalates by adding an oxalic acid aqueous solution. Finally, the DES can be regenerated by evaporating the water. Importantly, valuable metals can be recovered with a 100 % yield through the process of DES recycling. This environmentally friendly and recyclable process is suitable for the recycling of spent lithium‐ion batteries industry. [ABSTRACT FROM AUTHOR]

The contents of organic acids (OAs) in tea beverage and their relationship with taste intensity have not been fully understood. In this work, a rapid (10 min for a single run) and sensitive (limits of quantification: 0.0044–0.4486 µg/mL) method was developed and validated for the simultaneous determination of 17 OAs in four types of tea, based on liquid chromatography‐tandem mass spectrometry with multiple reaction monitoring mode. The contents of 17 OAs in 96 tea samples were measured at levels between 0.01 and 11.80 g/kg (dried weight). Quinic acid, citric acid, and malic acid were determined as the major OAs in green, black, and raw pu‐erh teas, while oxalic acid and tartaric acid exhibited the highest contents in ripe pu‐erh tea. Taking the OAs composition as input features, a partial least squares regression model was proposed to predict the sourness intensity of tea beverages. The model achieved a root‐mean‐square error of 0.58 and a coefficient of determination of 0.84 for the testing set. The proposed model provides a theoretical way to evaluate the sensory quality of tea infusion based on its chemical composition. [ABSTRACT FROM AUTHOR]

Waste PCBs the core of e‐waste is rich in copper, tin, zinc, iron, and nickel. Leaching base metals from PCB used to be done in toxic, corrosive acidic/alkali mediums. In this work, an environmentally friendly method for leaching metals from thermally treated PCBs (TPCBs) of mobile phones was proposed using choline chloride based deep eutectic solvents (DES). DES selectivity and solubility of metals from metal oxides were the main screening criteria. FA−ChCl had the maximum solubility of Cu, Fe, and Ni, while Urea−ChCl had high Zn selectivity and solubility. Oxalic acid has high selectivity for Sn. FA−ChCl extracted Cu and Fe best at 16 h, 100 °C, and 1/30 g/mL. Urea−ChCl extracted Zn (90.4±2.9 %) from TPCBs at 100 °C, 21 h, 1/20 g/mL, and 400 rpm. Oxalic acid (1 M) removed 92.3±2.1 % Sn from TPCBs in 1 h at 80 °C and 1/20 g/mL. The shrinking core model‐based kinetic investigation of FA−ChCl for Cu extraction showed a diffusion‐controlled process. The proposed method is greener than mineral acids utilized for metal extraction. [ABSTRACT FROM AUTHOR]

The present study reports an environmentally friendly in‐situ synthesis of novel antibacterial copper‐based MOFs within the hydrogel network of sodium alginate. Two different copper‐based MOF/sodium alginate composite beads were prepared via the post‐treatment of copper‐ion‐crosslinked alginate hydrogels with two different ligand solutions, namely, tartaric acid and oxalic acid, at 100 °C for 24 h. The structural, thermal, and morphological properties of the prepared samples were investigated using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), and their antibacterial activities against gram‐positive (Staphylococcus aureus and Bacillus) and gram‐negative (Escherichia coli and Pseudomonas aeruginosa) strains were examined using the conventional disc diffusion method. The results demonstrated the success of the in‐situ synthesis of two distinct copper‐based MOFs with FTIR spectra, confirming the existence of characteristic bands of the ligands complexed to the sodium alginate matrix. Moreover, the XRD diffractograms revealed the formation of two distinct crystalline structures with well‐defined morphologies observed in the SEM images. In addition, thermal analysis showed that the prepared composite beads had enhanced thermal stability compared to the copper‐ion‐crosslinked alginate beads. Antibacterial testing revealed the strong capacity of the copper‐based MOFs/sodium alginate composite beads to deactivate the growth of all the bacterial strains used, with a minimum inhibition zone of 23 mm, which highlights the potential of the synthesized materials as highly potent antibacterial agents. [ABSTRACT FROM AUTHOR]

This study conducts hydrothermal leaching of commercial LiFePO4 (LFPO) cathode materials with oxalic acid, citric acid, or glycine without any other oxidants or reductants. Of these acids, glycine exhibits the weakest leaching behavior, with the leaching efficiency of lithium (Li), iron (Fe), or phosphorus (P) less than 15% even at 200 °C and an acid concentration of 0.8 mol L−1 for 10 min. For oxalic acid, at 200 °C for 10 min, with a pulp density of 30 g L−1 and an acid concentration of 0.8 mol L−1, the leaching efficiencies for Li and P are 100% and 97%, respectively, and 98.5% of Fe precipitates as iron oxalate (FeC2O4) that can be used as a precursor for preparing LFPO cathode materials. Citric acid shows the highest leaching efficiency for Li, Fe, and P, reaching 96%, 100%, and 88%, respectively, at 90 °C for 10 min with a pulp density of 10 g L−1 and an acid concentration of 0.8 mol L−1. The continuous hydrothermal leaching of LFPO cathode materials with citric acid is first achieved. These results clarify the superiority of citric acid over oxalic acid and glycine with respect to the leaching efficiency for Li, Fe, and P from LFPO batteries under hydrothermal conditions. [ABSTRACT FROM AUTHOR]

The present research proposes investigating deep eutectic solvents for extracting Pb from biological samples for further determination by GF AAS. Among the synthesized solvents, the DES obtained from choline chloride and oxalic acid (ChCl : Ox) in a molar ratio 1 : 1 presented the best lead (Pb) extraction efficiency. Subsequently, it was characterized by Fourier Transform Infrared Spectroscopy (FTIR). For extraction, the optimized conditions were: 40 mg of sample, 400 μL of DES (ChCl : Ox) added, and 30 min at 95±5 °C. The supernatant was diluted, and the Pb was determined by GF AAS. The optimized instrumental conditions for Pb determination were 900 °C and 2100 °C, pyrolysis and atomization temperatures, respectively, using Pd as a chemical modifier. The limits of detection and quantification were 0.04 and 0.12 μg g−1, respectively. The method's accuracy was evaluated by analyzing the certificate reference materials, and good agreement was obtained between the determined and certificate values. The greenness of the proposed method was evaluated by green star and eco‐scale metrics. Thus, the proposed method proved simple, efficient, and eco‐friendly for determining Pb in biological samples. [ABSTRACT FROM AUTHOR]

Surface defects engineered nano‐Cu/TiO2 photocatalysts are synthesized through an easy and cost‐effective microwave‐assisted hydrothermal synthesis, mixing commercial P25 titania (TiO2) and oxalic acid (Ox), followed by 2.0 wt% Cu co‐catalyst (labeled as Cu2.0) loading through in situ photodeposition during reaction. The hydrothermal treatment does not affect the catalyst crystalline structure, morphology, nor the surface area. However, depending on the Ox/TiO2 molar ratio used an influence on the optical properties and on the reactivity of the system is detected. The presence of surface defects leads to intraband states formation between valence band and conduction band of bare titania, inducing an important enhancement in the photoactivity. Thus, Cu2.0/gOx/P25 200 (where g is the weight of Ox and 200 the temperature in Celsius degrees used during the synthesis) have been successfully tested as efficient photocatalysts for hydrogen production through methanol (MeOH) reforming under UV light in a MeOH/ H2O solution (10% v/v) by fluxing the system with N2, showing an increased reactivity compared to the bare Cu2.0/P25 system. [ABSTRACT FROM AUTHOR]

Multiple impurities removal represents one of the most daunting challenges in gas purification, but the attainment of efficient adsorptive separation is hindered by the difficulty in designing adsorbents that could simultaneously capture different impurities. Herein, we revealed a molecular trap within Zn‐trz‐ox (trz = 1,2,4‐triazole; ox = oxalic acid) that featured positive H and negative O sites, and the suitable pore size, which exhibited remarkable one‐step C2H4 purification performance directly from quaternary C2H4/C2H2/C2H6/CO2 mixtures. The separation selectivities of C2H4 with respect to CO2, C2H2, and C2H6 are 9.8, 2.6, and 2.5, higher than the sole adsorbent yet reported. Meanwhile, polymer grade C2H4 (≥99.95%) could be directly obtained with record C2H4 productivity of 1.5 mol kg−1, over 10 times higher than that of the previous benchmark material. The deep insight into the binding behavior revealed by simulation studies offers important clues for the design of advanced adsorbent for multiple impurities capture. [ABSTRACT FROM AUTHOR]

The synthesis of glycoluril and its derivatives is carried out using the greener acids. We have screened four different greener acids for this synthesis, namely, (1) ethan‐1,2‐diyl bis(hydrogen sulfate) (EDSA), (2) NMP‐HSO4 ionic liquids (NHIL), (3) choline chloride: p‐TSA(ChCl:p‐TSA) DES and (4) choline chloride: oxalic acid (ChCl:OA) DES. These acids are easy to make, safe to handle, environmentally benign and recyclable. Along with the glycoluril, different glycoluril derivatives are also prepared. We have also developed a novel glycoluril derivative in which we have introduced 4‐bromophenyl moieties at 2nd and 6th position of the glycoluril. Our developed method is a one‐step reaction with shorter reaction time and high product yield. All the acids are recyclable up to four cycles without considerable loss of the yield. A comparative study of the yield obtained with the four acids is also carried out. [ABSTRACT FROM AUTHOR]

In China, liquid residue was mostly found in sealed bronze vessels associated with alcohol drinks, which are supposed to conserve the complete composition of the beverage, including the additives. So far, most of them have not been sufficiently scientifically verified. In this study, the liquid residue in bronze jars from the late Western Han period in the burial area of Jin Yang ancient city site was investigated by GC/MS, LC–MS/MS, SEM and Raman spectroscopy. These sensitive versatile techniques had unintended consequences in addition to confirming the presence of fermentation products (monosaccharides, alditols, glycerol‐related substances and organic acids). The enrichment of oxalic acid, VLCFA (very‐long‐chain fatty acid), and alkaloids hints that multiple plants were involved in the beverage preparation. The quinazoline alkaloid products from the sediments reveal an important Rutaceae ingredient, which relates to multiple ancient spices and Chinese herbs. Therefore, the liquid residues from Jin Yang ancient city site imply that they are the earliest known herbal wine remains in East Asia to this day. [ABSTRACT FROM AUTHOR]

BACKGROUND: Calcium is important in the formation of bones and teeth, cell metabolism, and other physiological activities. In this work, casein phosphopeptide‐calcium chelate (CPP‐Ca) was synthesized and the optimal process parameters for the chelation reaction were obtained. The bioavailability of calcium in CPP‐Ca was investigated by in vitro gastrointestinal simulated digestion. The existence of phytic acid and oxalic acid in the digestion system was evaluated to clarify the calcium holding ability of casein phosphopeptide (CPP). Liquid chromatography–tandem mass spectrometry (LC‐MS/MS) was used to identify oligopeptides from CPP‐Ca. RESULTS: The optimal process parameters for the chelation reaction were: peptide concentration 7.76 mgmL−1, pH 8.54, and reaction temperature 43.3 °C. The digestion in vitro results indicated that the calcium release rate of CPP‐Ca in the stomach for 2 h reached 85%, and about 50% of the ionized calcium was re‐chelated with CPP in the intestine. Phytic acid and oxalic acid could lead to a sharp decrease in soluble calcium but around 50% of the calcium was still retained in the form of chelates in the presence of CPP. The LC‐MS/MS identified 19 casein‐derived oligopeptides after digestion, and calcium modifications were found on eight peptides derived from β‐casein and αs2‐casein. CONCLUSIONS: This study clarified the excellent calcium holding capacity of CPP in the presence of phytic acid and oxalic acid. Liquid chromatography–tandem mass spectrometry also revealed peptide changes, and identified peptides that chelate with calcium. These findings provided significant insights that could be relevant to the further utilization and product development of peptide‐calcium chelate in the food industry. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The aim of our work is the preparation of cellulose nanofibrils or nanocrystals made from cellulose that is recovered from sugarcane bagasse agricultural waste (SC) as a dispersant instead of commercial cellulose for oil spill cleanup. In the current study, carboxymethyl cellulose was prepared by cellulose mercerization, which was then esterified by oxalic acid to create nanocellulose. Incorporation of oxalate into carboxymethyl cellulose (CMC) was verified by 1H‐NMR spectroscopy by the appearance of a new peak at 8.15 ppm for CMC–oxalate. The degree of substitution (DS) of oxalate was 0.17. The synthesized nanocellulose formed particles were roughly the same size and shape as both cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs): measuring 321–480 nm in length and 4–5 nm in width. Emulsions of paraffins made from CMC–oxalate are stable up to 10 months without undergoing precipitation. CMC–oxalate had great thermal stability and worked well as a paraffin oil dispersant. CMC–oxalate provided a barrier around the oil droplet surface, which prevented droplets from coalescing. This hypothesis is supported by the contact angle measurement for the O/W emulsion formed by CMC–oxalate being 0°, which is lower than the value for emulsions formed by underivatized CMC, 37.20°. From transmission electron microscopy observations, O/W emulsions of paraffin oil were spherical in shape, and separated from each other by a distance of 30–100 nm. This study shows that CMC–oxalate can be prepared by a low‐cost method, yielding nanocellulose with characteristics that resemble CNFs and CNCs, thereby opening up new potential applications for cellulose nanomaterials. [ABSTRACT FROM AUTHOR]

In the past decade, food-derivedmetal-chelating peptides (MCPs) have attracted significant attention from researchers working towards the prevention of metal (viz., iron, zinc, and calcium) deficiency phenomenon by primarily inhibiting the precipitation of metals caused by the gastrointestinal environment and exogenous substances (including phytic and oxalic acids). However, for the improvement of limits of current knowledge foundations and future investigation directions of MCP or their derivatives, several review categories should be improved and emphasized. The species' uniqueness and differences in MCP productions highly contribute to the different values of chelating ability with particular metal ions, whereas comprehensive reviews of chelation characterization determined by various kinds of technique support different horizons for explaining the chelation and offer options for the selection of characterization methods. The reviews of chelation mechanism clearly demonstrate the involvement of potential groups and atoms in chelating metal ions. The discussions of digestive stability and absorption in various kinds of absorption model in vitro and in vivo as well as the theory of involved cellular absorption channels and pathways are systematically reviewed and highlighted compared with previous reports as well. Meanwhile, the chelation mechanism on the molecular docking level, the binding mechanism in amino acid identification level, the utilizations of everted rat gut sac model for absorption, and the involvement of cellular absorption channels and pathway are strongly recommended as novelty in this review. This review makes a novel contribution to the literature by the comprehensive prospects for the research and development of food-derived mineral supplements. [ABSTRACT FROM AUTHOR]

A 3d–4f heterometallic compound, namely [Ni6GdL4(ox)(H2O)12]⋅[NO3]⋅14.5H2O (1) (L=2,2'‐phosphinico‐dibenzoate and ox=oxalate), was obtained by self‐assembly of nickel nitrate, gadolinium nitrate, oxalic acid, and 2,2'‐phosphinico‐dibenzoic acid (H3L). Such compound has been structurally characterized via single‐crystal X‐ray diffraction analysis and infrared spectroscopy. This compound features a basic unit of {Ni4Gd} clusters and 2,2'‐phosphinico‐dibenzoate ligands. Each unit is connected by another Ni2+ through the axial coordination of benzoate oxygen to form a layer. Meanwhile, each oxalate ligand bridges the expanded Ni4Gd‐Ni4 net, constructing a 3‐D framework. From the viewpoint of network topology, this compound can be simplified as a sqc6 topology. Magnetic analysis shows ferromagnetic interactions between the Ni(II) and Gd(III) centers in Ni4Gd nodes and antiferromagnetic coupling with oxalate bridges in this compound. [ABSTRACT FROM AUTHOR]

Preparation of cellulose nanofibrils (CNFs) with the pretreatments using alkanolamine‐based protic ionic liquids (PILs) with dimeric oxalic acid anions ([(HOA)(H2OA)]−) was fully investigated. The cation type [ethanolamine ([MEA]+), diethanolamine ([DEA]+), triethanolamine ([TEA]+)], and water addition greatly influenced the CNF yields. Under the pretreatment conditions of 110 °C and 3 h, the CNF yields with different PIL‐based systems followed the order: [MEA][(HOA)(H2OA)]>[DEA][(HOA)(H2OA)]>[TEA][(HOA)(H2OA)], similar to their swelling capacities. The highest CNF yield of 85.0 % was obtained after the pretreatment with [MEA][(HOA)(H2OA)]‐water containing 30 wt % PILs. The optimal pH range of PILs‐water was 1.10–1.15. The good recyclability indicated that these inexpensive PILs can be employed as a simple and efficient pretreatment system for preparing CNFs. The physicochemical properties of the prepared CNFs were greatly changed by varying the PILs' pretreatment systems. The thermal stability of CNFs was intimately connected with the crystalline structures and hydrogen bonding modes. [ABSTRACT FROM AUTHOR]

Summary: The properties of pectin extracted by enzyme‐assisted nitric acid (EAE‐N) and pectin extracted by enzyme‐assisted oxalic acid (EAE‐O) were analysed and compared with pectin extracted by nitric acid (AE‐N) and pectin extracted by oxalic acid (AE‐O) systematically. The yield of pectin obtained by the enzyme‐assisted acid method (23.73% ~ 25.60%) was significantly higher than that by acid extraction method (19.75% ~ 20.60%). Monosaccharide analyses demonstrated that the enzyme‐assisted acid method was able to attain more branched rhamnogalacturonan I (RG‐I) regions (36.59% ~ 42.06%) than using acid solely (31.01% ~ 34.58%). Fourier transform infrared spectroscopy (FT–IR) and nuclear magnetic resonance (1H NMR) analyses indicated that there was no obvious difference in the characteristic structure of pectin. The atomic force microscopy (AFM) images revealed that EAE‐N and EAE‐O had more short side chains and cross‐link compared with AE‐N and AE‐O. Thermogravimetric analysis (TGA) shows that EAE‐N and EAE‐O have good thermal stability. All pectin samples showed a shear‐thinning fluid flow behaviour and an elastic gel‐like behaviour. The results suggested that enzyme‐assisted acid provided a viable alternative method for the extraction of pectin. [ABSTRACT FROM AUTHOR]

Summary: Carambola is a nutrient‐rich tropical fruit that ripens and spoils rapidly at ambient temperature, making low‐temperature storage a preferable method to address this problem. Unfortunately, carambola suffered a chilling injury when stored at low temperatures. Carambola was vacuum impregnated with melatonin (MT), γ‐aminobutyric acid (GABA), and oxalic acid (OA) to mitigate chilling injury and improve its quality during cold storage. Carambola fruits were stored at 4 °C for 28 days and analysed every 7 days. Weight loss, firmness, physicochemical properties, phenolic content, flavonoid content, and proline content were assessed. MT‐treated carambola has the highest firmness, 146.31 g and lowest weight loss, 1.53% in comparison to others by the end of the storage period. Visual observations showed that MT‐treated carambola ripened evenly, without any chilling injury symptoms and decay was also delayed, whereas OA‐ and GABA‐treated carambola started to decay on day 28. Instead of degrading, phenolics and flavonoids were retained with 6.10% and 12.67% increase when compared to the initial level. GABA‐treated carambola can also retain its phenolic and flavonoid content; meanwhile, OA‐treated carambola can only retain its phenolic content. Therefore, MT can be applied to mitigate chilling injury and maintain the quality of carambola. [ABSTRACT FROM AUTHOR]

Herein, H+ in oxalic acid is used instead of Naþ to obtain titanate nanosheets through P200 hydrolysis, which further curls to form a multilayer TiO2 nanotubes (NTs) structure. Then, Cu2O quantum dots (QDs) are successfully loaded on TiO2 NTs via a hydrothermal method using fructose as a reducing agent. The optical, impedance, and photocurrent tests indicate that the composite structure improves its optoelectronic performance. The photocatalytic H2 production and CO2 reduction efficiency of Cu2O QDs/TiO2 NTs are lower than those of TiO2 NTs. However, the molar ratio of CH4 to CO produced by CO2 reduction of Cu2O QDs/TiO2 NTs composite catalyst is greater than that of pure TiO2 NTs. The CH4 production accounts for 97%, indicating that the composite catalyst has a high CH4 selectivity. The experimental and density functional theory calculation results prove that the Z-scheme heterojunction accelerates the separation and transfer of photogenerated carriers, and broadens the absorption range of visible light. [ABSTRACT FROM AUTHOR]

Bacterial panicle blight is caused by Burkholderia glumae and results in damage to rice crops worldwide. Virulence of B. glumae requires quorum sensing (QS)‐dependent synthesis and export of toxoflavin, responsible for much of the damage to rice. The DedA family is a conserved membrane protein family found in all bacterial species. B. glumae possesses a member of the DedA family, named DbcA, which we previously showed is required for toxoflavin secretion and virulence in a rice model of infection. B. glumae secretes oxalic acid as a "common good" in a QS‐dependent manner to combat toxic alkalinization of the growth medium during the stationary phase. Here, we show that B. glumae ΔdbcA fails to secrete oxalic acid, leading to alkaline toxicity and sensitivity to divalent cations, suggesting a role for DbcA in oxalic acid secretion. B. glumae ΔdbcA accumulated less acyl‐homoserine lactone (AHL) QS signalling molecules as the bacteria entered the stationary phase, probably due to nonenzymatic inactivation of AHL at alkaline pH. Transcription of toxoflavin and oxalic acid operons was down‐regulated in ΔdbcA. Alteration of the proton motive force with sodium bicarbonate also reduced oxalic acid secretion and expression of QS‐dependent genes. Overall, the data show that DbcA is required for oxalic acid secretion in a proton motive force‐dependent manner, which is critical for QS of B. glumae. Moreover, this study supports the idea that sodium bicarbonate may serve as a chemical for treatment of bacterial panicle blight. [ABSTRACT FROM AUTHOR]

Gonipterus sp. n. 2 (Coleoptera, Curculionidae) is an invasive, commercially important weevil that causes large‐scale defoliation of Eucalyptus trees. The weevil specifically feeds on young leaves and new shoots, thus reducing tree growth. The weevil displays a very strong preference for certain Eucalyptus genotypes, however, this behaviour and the chemistry underlying it is poorly understood, thereby complicating the selection of resistant trees. To elucidate the feeding preference of Gonipterus sp. n. 2, we assessed the relative levels of susceptibility of 62 Eucalyptus genotypes from 23 species using a laboratory choice assay. This revealed large intraspecific variation in susceptibility to weevil feeding, which for certain species, exceeded the interspecific variation. A semiquantitative metabolite profile analysis on 13 genotypes revealed strong correlations of 10 metabolites to feeding damage. The behavioural effects of the identified compounds were assessed through an in vitro feeding preference assay using artificial diets as well as under field conditions. This revealed three phagostimulants (1,8‐cineole, oxalic acid and sucrose) and two feeding deterrent compounds (shikimic acid and palmitic acid) for Gonipterus sp. n. 2. These chemical markers can be applied to tree breeding programmes for the selection of resistant genotypes to reduce damage caused by Gonipterus weevils. Summary statement: Laboratory choice assays on 62 Eucalyptus genotypes from 23 species, detailed metabolic profiling, in vitro feeding assays and independent field trials revealed three phagostimulants and two feeding deterrent compounds for Gonipterus sp. n. 2. [ABSTRACT FROM AUTHOR]

The demand for environmentally friendly and non‐petroleum based natural rubber products is on the rise. Sepiolite, a one‐dimensional clay mineral, has been found to be a suitable reinforcement for natural rubber through latex compounding. However, the aggregation of fibers and minerals may impact the overall properties of natural rubber composites. To overcome this challenge, the study utilized ultrasonic disaggregation and oxalic acid activation to prepare stable sepiolite suspensions with varying specific surface areas and surface activities. These suspensions were then mixed with natural rubber latex to prepare NR/sepiolite composites. The results showed that the dispersibility and bonding ability of sepiolite with natural rubber were improved due to the increased specific surface area and surface activity, resulting in more bonding sites. The mechanical properties of the composites were also found to be improved, with a significant increase in tear strength (from 61.9 to 67.6 N·mm−1) and tensile strength (from 23.0 to 29.5 MPa). This research lays a strong foundation for the utilization of sepiolite in rubber materials. [ABSTRACT FROM AUTHOR]

Background: Aspergillus niger is generally considered safe and is widely used across a broad range of industries from food to pharmaceuticals. The metabolites of some Aspergillus species are effective in killing nematodes. The active ingredients that play a role are citric acid and oxalic acid. Results: The effective nematocidal metabolite in the fermentation broth of the A. niger Ym16 is a calcium oxalate coordination compound (C2H2O4•2(C2HO4)•C2O4•4(H2O)•2(Ca)). The mortality of fermentation broth and compound solution to second‐stage juveniles (J2s) of Meloidogyne incognita were 94% (8 h) and 95% (2 h), respectively. The hatching inhibition rates of fermentation broth and compound solution to eggs of M. incognita were 86% (24 h) and 87% (12 h), respectively. Furthermore, the Ym16 strain promoted plant growth. Conclusion: Strain Ym16 and its metabolites should be the first choice for nematode control because it is an effective agent against soil nematodes. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Solution processed perovskite films usually exhibit numerous defect states on the surfaces of the films. Here in this work, oxalic acid (H2C2O4), which has two C=O groups, is selected and used to passivate the surface defects of the two‐step deposited perovskite films via post‐treatment. Strong interaction between H2C2O4 molecule and the Pb2+ ions located on the surface of perovskite film has been confirmed via Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, which can result in an effective suppress of the surface defects. Furthermore, time‐resolved PL spectrum indicates that carrier lifetime is prolonged in the H2C2O4 passivated perovskite film. After optimizing the H2C2O4 concentration, the target perovskite solar cells can demonstrate superior power conversion efficiencies (21.67 % from reverse measurement and 21.54 % from forward measurement) and superior device‐stability. [ABSTRACT FROM AUTHOR]

The widespread presence of organic aerosols (OA) in the atmosphere and their dominant role in climate forcing are increasingly recognized. Measurements from the high‐altitude region provide insights into the natural processes and long‐range transport of aerosols. We studied water‐soluble organic compounds in PM1.1 during January‐March 2020 and February‐April 2021 at Ponmudi (8.8°N and 77.1°E), a tropical hill station (960 m a.s.l.) located on the Western Ghats of India. The 5‐day backward trajectories of air masses presented that continental and marine sources impacted the site during the campaign, and thus we classified samples as mixed and marine air masses. Their molecular fingerprints revealed the prevalence of oxalic acid (C2), followed by terephthalic acid in mixed air mass and malonic (C3) or succinic (C4) acid in maritime air mass aerosol samples. This feature and the phthalic to azelaic acid ratio, as well as the C3 to C4 and fumaric to maleic acid ratios, evidenced that water‐soluble OA were of anthropogenic origin and less photochemically aged in mixed air mass samples, whereas they derived from biogenic sources and more photochemical aging in marine air mass samples. However, we found their comparable contributions in water‐soluble organic carbon under mixed and marine air masses. Linear correlations between C2 relative abundance and its ratios with the precursor compounds implied that the oxidation of precursors to oxalic acid occurs during atmospheric transport. The results revealed that the input of anthropogenic and biogenic precursors followed by atmospheric processing controlled the burden of water‐soluble OA across the Western Ghats. Plain Language Summary: Dicarboxylic acids (DCAs), oxocarboxylic acids and dicarbonyls are ubiquitous water‐soluble components of organic aerosol (OA) that can serve as cloud condensation nuclei and affect the climate of the Earth. We reveal for the first time the molecular fingerprints and sources as well as formation processes of water‐soluble OA in PM1.1 at a tropical hill station in Western Ghats of India. Significant differences in the molecular fingerprints and atmospheric processes of water‐soluble OA were found due to the influence of different air masses. DCAs and related compounds in mixed air mass aerosols originated from anthropogenic sources and produced in the atmosphere by photooxidation during long‐range transport whereas they were of biogenic origin followed by intense photochemical aging of biogenic volatile organic compounds such as isoprene and unsaturated fatty acids during atmospheric transport in marine air mass aerosols. The results revealed that DCAs substantially contribute to water‐soluble OA not only in mixed air mass aerosols but also in marine air mass aerosols at the tropical hill station in the Western Ghats. These findings have implications for assessing climate‐forcing feedback of secondary OA over the Western Ghats that is driven by anthropogenic and biogenic sources followed by photochemical processes. Key Points: Mixed and marine air masses drive the molecular fingerprints of atmospheric water‐soluble organic compounds over the Western GhatsAerosols of mixed air masses comprised dicarboxylic acids (DCAs) of anthropogenic origin and less photochemically processedDCAs were produced from biogenic sources followed by intense photochemical aging in marine air mass aerosols [ABSTRACT FROM AUTHOR]

Removal of manganese (Mn) and iron (Fe) oxide coatings from indicators of reduction in soil (IRIS) is considered a function of microbial reduction of these elements under sufficiently reducing conditions, but there may be situations where removal is abiotic. We examined whether abiotic removal of Mn and Fe oxide coatings may be facilitated by organic acids and whether loss of Mn can take place via chemical reduction by ferrous iron (Fe2+) in vitro. Loss of color from Mn‐IRIS in citric acid solution was highest at 1 and 10 mM regardless of pH, with no loss observed at lower concentrations. Effects of citric acid on Fe‐IRIS were also limited to 1 and 10 mM, but color loss only occurred at pH 4.5 and the rate and extent of loss were lower than for Mn‐IRIS. Color loss from Mn‐IRIS in oxalic acid was highest at 1 and 10 mM and increased with decreasing pH. Effects of oxalic acid on loss of color from Fe‐IRIS were limited to 1 and 10 mM. Loss of color from Mn‐IRIS was limited to 10 mM salicylic acid and pH 4.5, with no effect on Fe‐IRIS regardless of concentration and pH. Only the two highest concentrations of Fe2+ (50 and 100 mM) resulted in reduction of the Mn‐IRIS coating and subsequent deposition of an Fe oxide coating. Organic acids and pH have a differential effect on color loss from Mn‐ and Fe‐IRIS, with only high concentrations of organic acids at low pH possibly interfering with interpretation. Core Ideas: Indicators of reduction in soil (IRIS) are used to assess redox conditions in soils, particularly in wetland soils.We assessed the role of organic acids and Fe2+ as interferences in lab experiments.Interference with IRIS is unlikely except for soil with mM concentrations of the organic acids or Fe2+. [ABSTRACT FROM AUTHOR]

In this study, different polyanilines were synthesized and evaluated for the determination of three hormones, including 17‐β‐estradiol, 17‐α‐ethinylestradiol, and estrone, in urine using a novel methodology based on thin film solid‐phase microextraction technique, employing the sampling well plate system. The extractor phases, designated as polyaniline doped with hydrochloric acid, polyaniline doped with oxalic acid, polyaniline‐silica doped with hydrochloric acid, and polyaniline‐silica doped with oxalic acid, were characterized by electrical conductivity measurements, scanning electron microscopy, and Fourier transform infrared spectroscopy. The optimized extraction conditions were composed of 1.5 mL of urine and pH adjusted to 10, with no need to dilute sample and the desorption step, 300 μL of acetonitrile was used. The calibration curves were performed in the sample matrix, with detection and quantification limits ranged from 0.30 to 3.03 μg L−1 and from 1.0 to 10.0 μg L−1, respectively, with r ≥ 0.9969. The relative recoveries ranged from 71% to 115%, and intraday precision showed values ≤12% and interday ≤20%. The applicability of the method was successfully evaluated, and six urine samples from female volunteers were analyzed. The analytes were not detected or were below the limits of quantification in these samples. [ABSTRACT FROM AUTHOR]

The current examination dealt with the development of a methodology to produce quercetin, a multifunctional bio‐flavonoid, by designing task‐specific, highly acidic deep eutectic solvents, based on glycerol and natural organic acids. The purpose was to achieve a simultaneous hydrolysis of spiraeoside, the major quercetin glycoconjugate occurring in onion solid wastes, and quercetin extraction. After an initial performance screening, the combination of glycerol/oxalic acid was identified as the highest‐performing system, and further investigation showed that the most efficacious molar ratio was glycerol/oxalic acid 3:1. Further study of hydrolysis/extractions conditions suggested 30 min, at 130°C, to be the best operating conditions, giving the highest yield of 19.65 mg quercetin per grams of dry mass. The extract obtained under these conditions displayed significantly enhanced antiradical activity, compared to control extracts prepared with water or aqueous ethanol. On the other hand, results on the ferric‐reducing power were rather contradictory. It is proposed that such a methodology may be implemented to valorize onion solid wastes, for the production of extracts significantly enriched in quercetin, with increased antiradical properties. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fungal diseases remain important causes of crop failure and economic losses. As the resistance toward current selective fungicides becomes increasingly problematic, it is necessary to develop efficient fungicides with novel chemotypes. RESULTS: A series of novel quinazolin‐6‐ylcarboxylates which combined the structures of pyridine or heterocyclic motif and the N‐(3‐chloro‐4‐fluorophenyl)quinazolin‐4‐amine moiety, a binding group of ATP‐binding site of gefitinib, were evaluated for their fungicidal activity on different phytopathogenic fungi. Most of these compounds showed excellent fungicidal activities against Botrytis cinerea and Exserohilum rostratum, especially compound F17 displayed the highest activity with EC50 values as 3.79 μg mL−1 against B. cinerea and 2.90 μg mL−1 against E. rostratum, which was similar to or even better than those of the commercial fungicides, such as pyraclostrobin (EC50, 3.68, 17.38 μg mL−1) and hymexazol (EC50, 4.56, 2.13 μg mL−1). Moreover, compound F17 significantly arrested the lesion expansion of B. cinerea infection on tomato detached leaves and strongly suppressed grey mold disease on tomato seedlings in greenhouse. The abilities of compound F17 to induce cell apoptosis of the non‐germinated spores, to limit oxalic acid production, to reduce malate dehydrogenase (MDH) expression, and to block the active pocket of MDH protein were demonstrated in B. cinerea. CONCLUSION: The novel quinazolin‐6‐ylcarboxylates containing ATP‐binding site‐directed moiety, especially compound F17, could be developed as a potential fungicidal candidate for further study. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Starch straws are developed by focusing on improving the critical weakness of all starch‐based materials: moisture sensitivity. Various technologies including blending (with hydrogel carrageen), chemical crosslinking (using citric and boric acids, and furfural), physical barrier (using talc), and surface modifications (by adding stearic acid, or hot oxalic acids) are evaluated, and then synergized in this study. The materials and products are characterized by Fourier transform infrared spectroscopy, contact angle, mechanical properties, water solubility and water absorption. All the trends of individual modification are similar to previous work but it was found that the influence of some modifications on the extruded straws was significantly different from that of the casting films reported previously since extrusion with high shear stress can destroy chemical and physical crosslinking or network formed. It was found that there was a maximum acid content to improve the water sensitivity since the excessive amount of acid could degrade starch and have more damage to the crosslinking during extrusion, resulting in decreasing mechanical properties and increasing solubility. On the other hand, some synergic functions, like crosslinked by additional citric acid and surface treatment by hot oxalic acid, were observed. The promising starch straws are developed based on synergic methodologies, in which typical samples were prepared by crosslinking using citric (1 w%), boric (2 w%), talc (3 w%), and stearic acids (1 w%) and treated with hot oxalic acids for 2 s. The optimized straw can be smoothly processed, reduced water absorption significantly (55.3%), and mechanical properties (modulus) increased about 54% compared with neat starch one after being immersed in water at room temperature (25°C) for 20 min. This synergic strategy provides a useful guideline for developing starch‐based materials with low moisture sensitivity. [ABSTRACT FROM AUTHOR]