Direct Product Research Articles

Integrating Multipolar Structures and Carboxyl Groups in sp2‐Carbon Conjugated Covalent Organic Frameworks for Overall Photocatalytic Hydrogen Peroxide Production

The direct production of hydrogen peroxide (H2O2) through photocatalytic reaction via H2O and O2 is considered as an ideal approach. However, the efficiency of H2O2 generation is generally limited by insufficient charge and mass transfer. Covalent organic framework (COFs) offer a promising platform as metal‐free photocatalyst for H2O2 production due to their potential for rational design at the molecular level. Herein, we integrated the multipolar structures and carboxyl groups into COFs to enhance the efficiency of photocatalytic H2O2 production in pure water without any sacrificial agents. The introduction of octupolar and quadrupolar structures, along with an increase of molecular planarity, created efficient oxygen reduction reaction (ORR) sites. Meanwhile, carboxyl groups could not only boost O2 and H2O2 movement via enhancement of pore hydrophilicity, but also promote proton conduction, enabling the conversion to H2O2 from ·O2‐, which is the crucial intermediate product in H2O2 photocatalysis. Overall, we demonstrate that TACOF‐1‐COOH, consisting of optimal octupolar and quadrupolar structures, along with enrichment sites (carboxyl groups), exhibited a H2O2 yield rate of 3542 μmol h‐1 g‐1 and a solar‐to‐chemical (SCC) efficiency of 0.55%. This work provides valuable insights for designing metal‐free photocatalysts for efficient H2O2 production.

Integrating Multipolar Structures and Carboxyl Groups in sp2-Carbon Conjugated Covalent Organic Frameworks for Overall Photocatalytic Hydrogen Peroxide Production.

The direct production of hydrogen peroxide (H2O2) through photocatalytic reaction via H2O and O2 is considered as an ideal approach. However, the efficiency of H2O2 generation is generally limited by insufficient charge and mass transfer. Covalent organic framework (COFs) offer a promising platform as metal-free photocatalyst for H2O2 production due to their potential for rational design at the molecular level. Herein, we integrated the multipolar structures and carboxyl groups into COFs to enhance the efficiency of photocatalytic H2O2 production in pure water without any sacrificial agents. The introduction of octupolar and quadrupolar structures, along with an increase of molecular planarity, created efficient oxygen reduction reaction (ORR) sites. Meanwhile, carboxyl groups could not only boost O2 and H2O2 movement via enhancement of pore hydrophilicity, but also promote proton conduction, enabling the conversion to H2O2 from ⋅O2 -, which is the crucial intermediate product in H2O2 photocatalysis. Overall, we demonstrate that TACOF-1-COOH, consisting of optimal octupolar and quadrupolar structures, along with enrichment sites (carboxyl groups), exhibited a H2O2 yield rate of 3542 μmol h- 1 g-1 and a solar-to-chemical (SCC) efficiency of 0.55 %. This work provides valuable insights for designing metal-free photocatalysts for efficient H2O2 production.

The super edge-connectivity of direct product of a graph and a cycle

The super edge-connectivity of direct product of a graph and a cycle

Direct Itaconate Production from Brown Macroalgae Using Engineered Vibrio sp. dhg.

Itaconate is a promising platform chemical with broad applicability, including the synthesis of poly(methyl methacrylate). Most studies on microbial itaconate production entail the use of crop-based feedstock, which imposes constraints due to its limited supply. Brown macroalgae have recently gained attention as next-generation biomass owing to their high biomass productivity and carbohydrate content and amenability to mass production. Therefore, the use of macroalgae for itaconate production warrants exploration. In this study, the direct production of itaconate from brown macroalgae was demonstrated using engineered Vibrio sp. dhg, which has emerged as an efficient platform host for brown macroalgal biorefineries. Specifically, to enhance production, cis-aconitate decarboxylase (Cad) from Aspergillus terreus was heterologously expressed and isocitrate dehydrogenase (icd) was deleted. Notably, the resulting strain, VIC, achieved itaconate titers of 2.5 and 1.5 g/L from a mixture of alginate and mannitol (10 g/L of each) and 40 g/L of raw Saccharina japonica (S. japonica), respectively. Overall, this study highlights the utility of brown macroalgae as feedstock, as well as that of Vibrio sp. dhg as a platform strain for improving itaconate bioproduction.

Finitely and non-finitely related words

An algebra is finitely related (or has finite degree) if its term functions are determined by some finite set of finitary relations. Nilpotent monoids built from words, via Rees quotients of free monoids, have been used to exhibit many interesting properties with respect to the finite basis problem. We show that much of this intriguing behaviour extends to the world of finite relatedness by using interlocking patterns called chain, crown, and maelstrom words. In particular, we show that there are large classes of non-finitely related nilpotent monoids that can be used to construct examples of: ascending chains of varieties alternating between finitely and non-finitely related; non-finitely related semigroups whose direct product are finitely related; the addition of an identity element to a non-finitely related semigroup to produce a finitely related semigroup.

Conjugate Graph and Conjugacy Class Graph related to Direct Product of Dihedral Groups

Conjugate Graph and Conjugacy Class Graph related to Direct Product of Dihedral Groups

Bioconversion of Alternative Substrates for the Biosynthesis of HMG-CoA Reductase Inhibitors by Aspergillus spp. Strains with Antimicrobial Potential

Simvastatin, a semisynthetic drug widely used to lower cholesterol, is among the most prescribed statins worldwide. This study focuses on the direct production of a simvastatin-like biomolecule using alternative substrates by Aspergillus spp. strains. Two species, A. terreus UCP 1276 and A. flavus UCP 0316, were initially evaluated in synthetic media as control. Subsequently, the carbon and nitrogen sources were replaced by agro-industrial substrates, resulting in five modified media. Cultures were maintained at 28 °C, pH 6.5, at 180 rpm for 21 days. Fungal growth kinetics were evaluated and a 23 full-factorial design (FFD) was used to investigate the influence of substrate concentration on statin yield. Presence of inhibitors was confirmed by bioassay, UV–visible spectrophotometry, and thin-layer chromatography (TLC). According to the results, A. flavus UCP yielded 0.24 mg/g of statin in condition 2 of FFD (medium containing 4.5% soluble starch and saline base), suggesting it as a promising candidate for direct production of the biomolecule. Statistical analysis showed the significant effect of soluble starch on inhibitor production, making it a viable and profitable alternative substrate. Moreover, the isolated statin exhibited broad-spectrum antimicrobial activity, including efficacy against Gram-negative and Gram-positive bacteria and yeasts, indicating therapeutic potential against antimicrobial resistance.

Ab initio MO study on direct production of H2O, N2O and CO3 from the respective CH2OO “Bee-sting-like” attack at H2, N2 and CO2

ContextWe have computationally elucidated the mechanism for formation of H2O, N2O and CO3 from the reactions of CH2OO with H2, N2 and CO2, respectively, by the direct attack of the terminal O atom of CH2OO. This unique mechanism, which is characteristically “bee-sting-like” in nature, was found to be closely parallel to their reactions with the O(1D) atom. Reactions with H2 and CO2 take place by side-on attack, while the N2 reaction occurs by end-on attack with predicted barriers, 19.4, 13.1 and 25.3 kcal.mol−1, respectively. The CO2 reaction with CH2OO was found to occur by producing the C2v CO3, O = C < (O)O, instead of its D3h conformer, essentially similar to the O(1D) + CO2 reaction. The rate constants for the three reactions have been computed by the transition state theory (TST) based on the predicted potential energy profiles. We have also utilized the isodesmic nature of the dative bond exchange in the N2 reaction, CH2O → O + N2 = CH2O + N2 → O, to estimate the heat of the formation of CH2OO. Based on the heat of reaction computed at the highest level of theory employed, we obtained ΔfHo0 (CH2OO) = 27.5 kcal.mol−1; the value agrees with the recent results within ± 1 kcal.mol−1.MethodsAll calculations were performed using Gaussian 16 software. Geometry, frequency, and IRC analysis calculations were conducted at the M06-2X/aug-cc-pVTZ level of theory. The heats of reaction have been evaluated at the highest level, CCSD(T)/CBS(T,Q,5)//M06-2x/aug-cc-pvTz.

Curious subgroups of $${\text {GL}}(2, {\mathbb {Z}}/ N {\mathbb {Z}})$$ as direct products of groups of distinct prime-power level

Curious subgroups of $${\text {GL}}(2, {\mathbb {Z}}/ N {\mathbb {Z}})$$ as direct products of groups of distinct prime-power level

Direct production of light scalars in the type-I two-Higgs-doublet model at the lifetime frontier of the LHC

A light pseudoscalar A in the sufficient large tanβ region of type-I two-Higgs-doublet model can be naturally a long-lived particle. We focus on H±A, HA, and AA pair productions via the electroweak processes mediated by the bosons at the LHC, including pp→W±/Z→H±/HA and pp→h→AA at the 14 TeV LHC. The possibility of probing A as a LLP at the FASER-2, FACET, MoEDAL-MAPP-2, and MATHUSLA is discussed. We find that FASER-2 fails to probe any parameter space within 0.2 GeV&lt;mA&lt;10 GeV for all the considered processes. For 130&lt;mH±=mH&lt;400 GeV, FACET, MoEDAL-MAPP-2, and MATHUSLA can probe tanβ≲104−6 for mA≲3 GeV, and tanβ≲106−8 for 3 GeV≲mA&lt;10 GeV from pp→W±/Z→H±/ZA processes. And pp→h→AA process covers similar parameter space. All processes can surpass the current limits. Published by the American Physical Society 2024

Enhancing the catalytic performance of Cu/ZnO/Al2O3 catalyst in methanol synthesis from biomass‐derived syngas with CeO2, MnO2 and ZrO2 as promoters

AbstractThe performance of Cu/ZnO/Al2O3 (CZA) catalysts promoted by addition of CeO2, MnO2 or ZrO2 in direct methanol production from unconventional syngas was experimentally investigated. The unconventional syngas used in this study contain 25% H2, 25% CO, 20% CH4, 20% CO2 and 10% N2, representing biomass‐derived syngas cultivated from an industrial wood chips pyrolysis plant. The catalysts were synthesised using co‐precipitation technique and tested for methanol synthesis in a fixed‐bed reactor. The activity test of the catalysts showed that the addition of CeO2 or ZrO2 to the CZA catalyst improved the methanol yield, albeit with lower selectivity, whereas adding MnO2 enhanced methanol selectivity but decreased the methanol yield. ZrO2‐promoted catalyst showed the best‐improved activity and stability. The calcined and spent catalysts were characterised using X‐ray diffraction (XRD), N2 physisorption, N2O chemisorption, hydrogen temperature‐programmed reduction (H2‐TPR) and X‐ray photoelectron spectroscopy (XPS). The characterisation results indicate that the catalytic activity is dependent on Cu dispersion, Cu‐active surface area, the catalyst reducibility, Brunauer–Emmett–Teller (BET) surface area and the Cu0/Cu+ ratio. In contrast, catalyst stability was related to the proportion of Cu+ among all surface Cu species.

Direct production of olefins from waste plastic using a pyrolysis and fluid catalytic cracking integrated process: Part 1. study on the production and analysis of waxy oil obtained using a new type of a fluidized bed reactor

The ultimate aim of this research is to produce ethylene and propylene directly from waste plastic. To achieve this, we designed a new cracker having a fluidized bed reactor (FBR) and a fluid catalytic cracking (FCC) unit. The FBR produces oil in vapor phase, and the FCC unit transforms the vapor into olefins. As a first step toward achieving the research goal, the current study conducts pyrolysis of low-density polyethylene using a new pyrolysis process having a FBR. By understanding characteristics of pyrolysis oils obtained in this study, it becomes possible to determine its suitability as FCC feed and its relationship with olefin productivity. The current investigation focused on the effects of vapor residence time, reaction temperature, and type of fluidizing medium on yield and composition of oil. The results showed that the waxy oil yield depended highly on reaction temperature, reaching a maximum of about 95 wt%. The sum of yields of n-alkenes and n-alkadienes, which are favorable for producing olefins when catalytically cracked in the FCC unit, reached 82 wt%. SIMDIS analysis, which determines the boiling point range distribution of oil, revealed strong effects of reaction temperature and residence time on the carbon numbers of the waxy oil.

Direct lactic acid production from raw jerusalem artichoke powder by Lacticaseibacillus paracasei NJ and the comparative transcriptomic profiling of inulin and monosaccharide utilization

A feasible fermentation process for the production of lactic acid (LA), one of the most important food additives, from non-crop feedstocks would help alleviate the challenges of food safety. In this study, 215 g/L inulin-rich Jerusalem artichoke powder (JAP) were directly converted into LA without exogenous nitrogen addition under non-sterile conditions via selected Lacticaseibacillus paracasei NJ. The LA concentration, yield, and average productivity reached 144.08 g/L, 0.67 g/g, and 4.37 g/L/h, respectively, which can be scalable from 5 L to 50 L bioreactors. The viable counts of Lacticaseibacillus reached to 142.30–301.50 × 108 CFU/mL, allowing the products a promising probiotic in food additives. Transcriptional analysis revealed that strain NJ utilized inulin mainly via extracellular β-fructosidase and fructose transporters encoded by the fosRABCDXE operon, and the gene expression within the phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS), pyruvate metabolism, and fatty acid synthesis was significantly altered. For strain NJ grown on JAP, the expressions of genes related to amino acid biosynthesis and peptide/amino acid relevant ATP-binding cassette (ABC) transport system were upregulated to fit nitrogen limitation. We found the availability of L. paracasei NJ for high-yield lactic acid from raw JAP and explores the inner changes of gene expression by utilizing inulin, which provide both promising food additives and new perspectives on the understanding of inulin metabolism in Lacticaseibacillus.

Isobutyric and n-butyric acid production from H2 and CO2 by Clostridium luticellarii in a hollow fiber membrane biofilm reactor: Reactor operation and process modelling

Clostridium luticellarii is an acetogen uniquely capable of producing acetic, n-butyric and isobutyric acid from H2 and CO2. Since n-butyric and isobutyric acid are currently produced from petrochemically derived propylene, establishing a direct production route from CO2 and H2 could greatly improve their sustainability as platform chemicals while simultaneously capturing carbon. Here, we demonstrate for the first time the production of these acids from H2 and CO2 by C. luticellarii in a continuously operated hollow fiber membrane biofilm reactor (HFMBR). The HFMBR was operated for 80 days while gradually increasing the H2:CO2 ratio from 2.5 to 5.0. Concentrations of acetic, n-butyric and isobutyric acid of respectively 8.93 ± 0.22 g L−1, 1.56 ± 0.04 g L−1 and 1.51 ± 0.06 g L−1 were achieved at a dilution rate of 0.25 d−1. Subsequently, a holistic process model was developed to gain deeper insights into the performance of the system and how to optimize its operation. The model described the autotrophic production of the acids, as well as mass transfer of H2 and CO2 through the membrane, biofilm diffusion and convective movement of particulates, and biofilm growth and detachment. Calibration against experimental data confirmed the model accuracy in reflecting the production dynamics (NRMSE of products < 0.1). Scenario analyses highlighted the importance of biofilm thickness control to minimize pH gradients and revealed that increased membrane surface area and optimized dilution rates are critical in enhancing volumetric production rates and steering product selectivity. Overall, these combined experimental results and model-generated insights can inform future optimization of HFMBRs for the production of added-value products from H2 and CO2.

Hydrogen bond regulation to promote the direct production of diosgenin from Dioscorea zingiberensis rhizomes

Herein, a renewable system consisted of tartaric acid and isopropanol was developed to produce diosgenin efficiently from Dioscorea zingiberensis rhizomes. The yield of diosgenin reached 4.15% comparable to the highest value reported in previous researches. The combination of experiment and DFT calculation revealed that the acid-alcohol system could regulate the hydrogen bond interaction of each component in the rhizomes to disassemble the connection network and promote the release of saponin. Meanwhile, the intramolecular hydrogen bond of tartaric acid and the steric hindrance effect of isopropanol could prevent the esterification reaction and maintain the strong acidity of the system for the high yield of diosgenin. The scale-up experiment with a 100-fold feeding capacity was also conducted successfully. Furthermore, the technological process integrated with purification of diosgenin, recovery of organic acid and solvent and upgrading of residual solid to porous carbon materials has been established systematically to verify the prospective of industrialization.

When the Tracy-Singh product of matrices represents a certain operation on linear operators

Given two linear transformations, with representing matrices A and B with respect to some bases, it is not clear, in general, whether the Tracy-Singh product of the matrices A and B corresponds to a particular operation on the linear transformations. Nevertheless, it is not hard to show that in the particular case that each matrix is a square matrix of order of the form n 2, n > 1, and is partitioned into n 2 square blocks of order n, then their Tracy-Singh product, A ⊠ B , is similar to A ⊗ B , and the change of basis matrix is a permutation matrix. In this note, we prove that in the special case of linear operators induced from set-theoretic solutions of the Yang-Baxter equation, the Tracy-Singh product of their representing matrices is the representing matrix of the linear operator obtained from the direct product of the set-theoretic solutions.

Estimation of LAI of tobacco plant using selected spectral subsets of visible and near-infrared reflectance spectroscopy

Flue-cured tobacco is a main economic crop, and leaves are the direct product of tobacco plant. Monitoring leaf area index (LAI) of tobacco plant is important to field management, yield prediction, and industry regulation. Hyperspectral data have hundreds of narrow spectral bands in continuous spectral ranges, significantly advancing monitoring of LAI. However, considering spectral responses of LAI vary with wavelength, the use of the full spectral range in estimation of LAI is redundant. To reduce spectral redundancy and improve estimation of LAI, spectral subsets were selected based on importance of spectral bands. Variable importance in the projection (VIP) score obtained by partial least squares regression (PLSR) was adopted to measure the importance. The study was conducted in Yunnan Province, China. Canopy reflectance spectra of tobacco plant were measured in two consecutive growth seasons. Genetic algorithm (GA) and PLSR were used for model calibration. The identified important spectral regions for estimation of LAI were red edge, near-infrared (NIR), and green regions. In estimation of LAI of tobacco plant, compared with the estimation using the full spectral range of VNIR reflectance spectra, normalized root mean square error (NRMSE) and coefficient of determination (R2) values were improved from 10.30% and 0.83 to 7.68% and 0.90 and from 18.78% and 0.43 to 7.65% and 0.90 by using the reflectance spectra in identified spectral regions in the growth seasons in 2021 and 2022 separately. In addition to the identified continuous spectral regions, central bands of the identified spectral regions also achieved estimation of LAI, with the highest R2 value reaching 0.72. The selected spectral subsets improved estimation accuracy and reduced model complexity. The results indicate that selected spectral subsets are effective and promising in estimation of LAI, providing an alternative for estimation of LAI using hyperspectral data.

On finite groups with the Magnus Property

AbstractWe investigate finite groups with the Magnus Property (MP), where a group is said to have the MP if whenever two elements have the same normal closure, then they are conjugate or inverse conjugate. In particular, we observe that a finite MP group is solvable, determine the finite primitive MP groups, and determine all the possible orders of the chief factors of a finite MP group. We also determine the MP finite direct products of finite primitive groups, as well as the MP crown‐based powers of a finite monolithic primitive group.

Copper-supported hydroxyapatite catalysts for bio-isobutanol synthesis from sustainable short-chain alcohols

Developing high-performance catalysts for the direct production of isobutanol through the Guerbet reaction is a challenge today, due to the potential of isobutanol as fuel. The present study describes the synthesis and characterization of Cu-supported hydroxyapatite catalysts. The synthesis of isobutanol has been investigated through batch experiments and in a continuous-flow reactor operating in a gas-solid phase. This study used ethanol and methanol as the primary feedstock for the synthesis process. It was found that Cu supported hydroxyapatite catalysts are capable of catalyzing the formation of isobutanol from CH3OH and C2H5OH at temperatures (300–500 ºC) and 1 atm in a continuous flow reactor. Notably, the highest selectivity to isobutanol was observed at 400 ºC. The use of Cu10/HAP 1.65 catalyst in a batch reactor greatly enhances the selectivity of iBuOH in the liquid phase, increasing it from 18 % (vapor-phase) to 65 %. The data showed that the reaction of ethanol/methanol was limited by the 1-propanol-to-isobutanol reaction, which is a secondary reaction of the key intermediate. A reaction scheme has been proposed.

The Hepatoprotective Effect of Glycyrrhiza glabra Roots Extract Against Amiodarone Induced Hepatotoxicity in Male Rats

Amiodarone (AMD), a powerful antidysrhythmic medication, can cause hepatotoxicity when used long-term or in high doses. It affects both mitochondrial and lysosomal function because of its lipophilic nature and accumulation in tissues. It also has direct production of ROS. Glycyrrhiza glabra is one of the medicinal plants that have been commonly used for thousands of years. It possesses anti-ulcer, anti-inflammatory and antioxidant properties. In this study, the antihepatotoxic effect of Gg was evaluated against AMD liver toxicity in rats model, thirty rats were taken and divided evenly into five groups given daily doses by gastric gavage oral tube for 3 weeks as follows: the 1st group acted as a control group given D.W., and the 2nd group received AMD at a dose of 300mg/kg for 2 weeks. 3rd, 4th, and 5th groups were pretreated with Gg in doses of 200, 400, and 800 mg, respectively, for one week, then along with AMD for 2 weeks. Hepatic damage, revealed by histology and the increased activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and serum phospholipase A2 (PLA2) was decreased in the AMD group. Gg extract significantly reduced the elevated AST and ALT levels caused by AMD intoxication, rendering PLA2 to its normal level. It also enhanced liver superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) levels. Gg extract markedly reverses the increased serum TNF levels induced by AMD; therefore, it may be considered a good hepatoprotective agent.