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In the title compound, C9H11N3O·CH4O, the semicarbazone moiety is nearly planar [maximum deviation = 0.017 (2) Å] and is twisted by a dihedral angle of 29.40 (13)° with respect to the phenyl ring. The semicarbazone moiety and phenyl ring are located on opposite sides of the C=N bond, showing the E configuration. An intermolecular O—H...O and N—H...O hydrogen-bonding network occurs in the crystal structure.

Various excellent catalysts have been explored for the methanolysis of polycarbonate (PC), but it is still challenging to develop green and economical catalysts for solvent-free PC methanolysis to recover both bisphenol A (BPA) and dimethyl carbonate (DMC). Herein, green, efficient and solvent-free degradation of PC to BPA and DMC was achieved using urea as a cheap green catalyst. At 140 °C for 3 h, PC was completely degraded to BPA and DMC with yields of 93.4% and 74.7%, respectively. A possible catalytic degradation mechanism of PC was proposed by kinetic experiments and NMR, where urea, methanol and carbonate formed a six-membered ring in the reaction. It was found that the increase of urea concentration significantly reduced the activation energy, which was attributed to the fact that the increase of urea concentration made the six-membered ring easier to form and activated the carbonate bond. The degradation system can be reused directly up to 10 times and 100% degradation rate can be maintained. This work provides a simple, green and economical method for industrial PC recycling. [ABSTRACT FROM AUTHOR]

The present review proposes an approach for remediation of atmosphere pollution by carbon dioxide. The global economic growth nowadays requires extensive energy consumption. Energy is produced traditionally by combustion of carbon containing fuels, resulting in the release of large amounts of carbon dioxide in the atmosphere. These emissions of released CO2 lead to the greenhouse effect on the atmosphere with subsequent impact on the global climate. Remediation of this harmful effect requires reduction in CO2 emissions. In addition to improving the efficiency of energy consumption, this reduction can be also accomplished by the recycling of carbon dioxide into fuels and useful commodities. This conversion of CO2 into fuels and commercial products leads to multiple benefits such as reduction in carbon emissions and greenhouse gases, production of value-added goods, thus reducing oil consumption and associated pollutions of the environment. This review summarizes the efforts to remove, or at least to remediate, the release of carbon dioxide in the atmosphere by its conversion to value-added products prior to discharging. Some of these products are urea, methanol, formic acid, some polymers of practical importance, light hydrocarbons and methane. The recent achievements in chemical catalysis, electrochemistry, bioelectrochemistry and photocatalysis are considered. Discussion on the feasibility of the considered methods compared to the traditional technologies is made. It is concluded that although production of value-added chemicals by carbon dioxide recycling is not yet competitive, it seems promising in the future when its economic feasibility will become a reality. [ABSTRACT FROM AUTHOR]

Polycrystalline carbon nitride thin films were deposited on Si(400) and ITO coated glass substrates by electrolysis of methanol–urea solution under high voltage, at atmospheric pressure and at temperatures below 350 K. Fourier transform infrared spectroscopy (FTIR) measurements of the films deposited on Si suggested the existence of single, double and triple carbon–nitrogen bonds in the films. A maximum N/C atomic ratio of 0·81 was achieved in the films as measured by C/H/N analysis. X-ray diffraction spectra of the films grown with different urea concentrations showed various peaks for different d values, which could be assigned to different crystalline carbon nitride phases. Selected area electron diffraction patterns measured by transmission electron microscopy (TEM) showed a number of concentric sharp rings, corresponding to various planes of theoretically predicted β-C3N4 phase. Scanning electron microscopy (SEM) images of the films indicated the existence of grains, the number density and size of which were dependent on the solute concentration. Optical transmission measurements of the films on ITO coated glass substrates revealed a band gap value of around 2·87 eV for direct transition. The hardness of the films on Si substrates was as high as 28 GPa. [ABSTRACT FROM AUTHOR]

High-entropy multi-elemental (HEM) electrocatalysts present superior catalytic performance due to the efficient synergism of their components. HEM electrocatalysts are usually prepared through hydrothermal reactions or calcination, which could generate undesired heterogeneous structures that hinder the exploration of the structure-property relationship of these HEM electrocatalysts. Herein, we report a sol-gel method to synthesize homogeneous HEM electrocatalysts for electro-oxidation of methanol and urea (methanol oxidation reaction (MOR) and urea oxidation reaction (UOR)), through an acid-catalyzed gelation at room temperature. With Ni as the primary component for MOR and UOR, Co can reduce the overpotentials, while Fe can increase the catalytic activities and durability. Borate and phosphate can tune the charge distribution in active sites and speed up the reaction kinetics through fast proton transfer. Thus, the optimal Ni2Fe0.5Co0.5-BP HEM catalyst demonstrates superior catalytic activity together with good durability and great resistance to CO poisoning. In addition, a direct methanol fuel cell with Ni2Fe0.5Co0.5-BP electrode can not only provide power, but also produce formic acid with high yield and high Faraday efficiency. This work presents a simple strategy to prepare high-performance HEM electrocatalysts for fuel cells and production of value-added chemicals. [ABSTRACT FROM AUTHOR]

Various technologies including carbon capture and utilization or sequestration (CCUS) have been defined to achieve sustainability. CCUS aims to reduce global anthropogenic CO2 emissions to tackle climate change by capturing carbon at the source of emission and prevent its entry into the atmosphere. The captured carbon is then either utilized in industries or sequestered geologically. CO2 capture is accomplished by employing several methods like the use of membranes, chemical looping, cryogenic distillation, etc. Membranes provide a more effective and economic alternative as compared to the options that exist currently. Hence, in this paper we try to scrutinise the properties of certain mixed matrix membranes (MMM), alumina and zeolite-based membranes among others with respect to their selectivity towards flue gases, hoping to provide a broader understanding of current technology. The potential use of ionic liquids (ILs) to enhance properties of membranes will also be discussed. Next, this paper investigates the existing as well as possible carbon utilization pathways. Existing pathways include the usage of CO2 in the manufacturing of fertilizers, urea, methanol, oil and gas recovery in addition to water desalination projects and electrochemical conversion to certain chemicals. While we observe that ILs and MMMs provide good alternatives, an extensive further research is, however, still required for implementation of these ideas on an industrial scale. [ABSTRACT FROM AUTHOR]

Near-infrared light-triggered photocatalytic water treatment has attracted significant attention in recent years. In this novel research, rational sonochemical fabrication of Ag2S/g-C3N4 nanocomposites with various compositions of Ag2S (0–25) wt% was carried out to eliminate hazardous rhodamine B dye in a cationic organic pollutant model. g-C3N4 sheets were synthesized via controlled thermal annealing of microcrystalline urea. However, black Ag2S nanoparticles were synthesized through a precipitation-assisted sonochemical route. The chemical interactions between various compositions of Ag2S and g-C3N4 were carried out in an ultrasonic bath with a power of 300 W. XRD, PL, DRS, SEM, HRTEM, mapping, BET, and SAED analysis were used to estimate the crystalline, optical, nanostructure, and textural properties of the solid specimens. The coexistence of the diffraction peaks of g-C3N4 and Ag2S implied the successful production of Ag2S/g-C3N4 heterojunctions. The band gap energy of g-C3N4 was exceptionally reduced from 2.81 to 1.5 eV with the introduction of 25 wt% of Ag2S nanoparticles, implying the strong absorbability of the nanocomposites to natural solar radiation. The PL signal intensity of Ag2S/g-C3N4 was reduced by 40% compared with pristine g-C3N4, implying that Ag2S enhanced the electron–hole transportation and separation. The rate of the photocatalytic degradation of rhodamine B molecules was gradually increased with the introduction of Ag2S on the g-C3N4 surface and reached a maximum for nanocomposites containing 25 wt% Ag2S. The radical trapping experiments demonstrated the principal importance of reactive oxygen species and hot holes in destroying rhodamine B under natural solar radiation. The charge transportation between Ag2S and g-C3N4 semiconductors proceeded through the type I straddling scheme. The enriched photocatalytic activity of Ag2S/g-C3N4 nanocomposites resulted from an exceptional reduction in band gap energy and controlling the electron–hole separation rate with the introduction of Ag2S as an efficient photothermal photocatalyst. The novel as-synthesized nanocomposites are considered a promising photocatalyst for destroying various types of organic pollutants under low-cost sunlight radiation. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cell (MSC) therapy aids cardiac repair and regeneration, but the low rate of MSC survival and engulfment in the infarcted heart remains a major obstacle for routine clinical application. Here, an injectable suspension of human acellular amniotic membrane (HAAM) that may serve as synergistic cell delivery vehicle for the treatment of myocardial infarction (MI) by improving MSC homing and survival is developed. The results demonstrate that compared with MSC transplantation alone, HAAM‐loaded MSCs have higher survival and engraftment rates in infarcted tissue, alleviated hypoxia‐induced myocardial damage, achieved higher improvements in cardiac function, promoted angiogenesis, and reduced myocardial fibrosis. In addition, HAAM‐loaded MSCs increase N‐cadherin levels and thereby enhance the efficacy of MSCs in treating MI. This study provides a new approach for MSC‐based cardiac repair and regeneration. [ABSTRACT FROM AUTHOR]

The demand for food-grade β-mannanases, ideal for high-temperature baking, is increasing. Using the Komagataella phaffii (P. pastoris) expression system for β-mannanase production, this study aimed to enhance purification methods. We evaluated better conditions for production and purification of β-mannanase (PpRmMan134A) from recombinant P. pastoris X-33, focusing on a higher purity and reducing the production of endogenous secretory proteins in fermentation. By adjusting carbon and nitrogen sources, culture time, and temperature, we controlled cell growth to reduce the production of endogenous secretory proteins. The better-evaluated conditions involved culturing recombinant P. pastoris in 70 mL buffered glycerol complex medium for 24 h at 30 °C, then in modified buffered methanol-complex medium with 0.91% (w/v) methanol, 0.56% (w/v) sorbitol, and 0.48% (w/v) mannitol for another 24 h, which improved the PpRmMan134A yield and reduced endogenous secretory proteins, shortening the fermentation time by 72 h. An affordable purification method using ultrafiltration and salt-out precipitation was utilized. PpRmMan134A showed thermostability up to 100 °C and effectively degraded locust bean gum into smaller fragments, mainly producing mannotriose. In conclusion, with its enhanced purity due to reduced levels of endogenous secretory proteins, purified PpRmMan134A emerges as a promising enzyme for high-temperature baking applications. [ABSTRACT FROM AUTHOR]

Some of the largest scale chemical processes for the production of important commodity chemicals and fuels involve an H2-containing gas mixture as an intermediate [e.g. ammonia, urea, methanol, Fischer-Tropsch (F-T) diesel, and hydrotreatment of crude petroleum to refined fuels]. The successful development of a model H2-oxidizing chemoautotrophic host could expand the range of fuels and chemicals produced from H2 and CO2 intermediates in the chemical, oil, and gas sectors in the near term, as well as from renewable and waste-derived sources of these gases that are expected to greatly expand in coming years. Among non-photosynthetic bacteria that can utilize H2 and CO2, Cupriavidus necator (C. necator, formerly Ralstonia eutropha), is the best studied. C. necator is an excellent microbial host for the production of a variety of chemicals because it grows extremely quickly to very high cell densities autotrophically on H2 and CO2, is genetically tractable, and has the ability to accumulate polymers, such as polyhydroxybutyrate, at industrial levels. Despite having great potential as a platform bioproduction host, genetic tools are limited, making metabolic engineering of this organism slow and laborious. In this CRADA project, we developed a number of genetic tools for C. necator: 1) Improvement of C. necator genetic transformation efficiency2) Integration of heterologous genes into the C. necator chromosome and development of promoter library3) Development of graded RBSs to control heterologous protein expression4) Use of RBSs to demonstrate fatty alcohol production in C. necator5) Demonstration of CRISPR-Cas9 gene editing in C. necator

Seven fatty acids were detected by GC-MS in Xanthoceras sorbifolium Bunge seed oil extracted at different temperatures, including Palmitic acid C16:0, Stearic acid C18:0, Oleic acid C18:1, Eicosenoic acid C20:1, Docosenoic acid C22:1, Tetracosenoic acid C24:1, and Linoleic acid C18:2. The highest content of nervonic acid (NA) was found in Xanthoceras sorbifolium Bunge seed oil extracted at 70 °C. Three methods were selected to analyze the extraction rate of nervonic acid in Xanthoceras sorbifolium Bunge seed oil, including urea complexation, low-temperature solvent crystallization, and a combined treatment using these two methods. The final content of nervonic acid obtained was 14.07%, 19.66%, and 40.17%, respectively. The combined treatment method increased the purity of nervonic acid in Xanthoceras sorbifolium Bunge seed oil by 12.62 times. Meanwhile, thermogravimetric behavior analysis of samples extracted using different methods was conducted by thermogravimetric analyzer, which suggested that the thermal stability of the samples extracted by the combined treatment was enhanced. These results can provide a new process parameter and scientific basis for the extraction of NA. At the same time, FTIR and NMR were also used to characterize the combined extraction sample, and the structure of the samples was proved. [ABSTRACT FROM AUTHOR]

Hyperpolarization has become a powerful tool to enhance the sensitivity of magnetic resonance. A universal tool to hyperpolarize small molecules in solution, however, has not yet emerged. Transferring hyperpolarized, labile protons between molecules is a promising approach towards this end. Therefore, hydrogenative parahydrogen-induced polarization (PHIP) was recently proposed as a source to polarize exchanging protons (PHIP-X). Here, we identified four key components that govern PHIP-X: adding the spin order, polarizing the labile proton, proton exchange, and polarization of the target nucleus. We investigated the last two steps experimentally and using simulations. We found optimal exchange rates and field cycling methods to polarize the target molecules. We also investigated the influence of spin relaxation of exchanging protons on the target polarization. It was found experimentally that transferring the polarization from protons directly bound to the target X-nucleus (here 13C) of lactate and methanol using a pulse sequence was more efficient than applying a corresponding sequence to the labile proton. Furthermore, varying the concentrations of the transfer and target molecules yielded a distinct maximum 13C polarization. We believe this work will further help to understand and optimize PHIP-X towards a broadly applicable hyperpolarization method. Hyperpolarization has become a powerful tool to enhance the sensitivity of NMR analyses, whereby hydrogenative parahydrogen-induced polarization with exchanging protons could broaden its applicability. Here, the authors identify four key components that govern the polarization of exchanging protons, and propose optimal exchange rates and field cycling methods to polarize target molecules. [ABSTRACT FROM AUTHOR]

Hierarchical porous structures and well-modulated interfacial interactions are essential for the performance of electrode materials. The energy storage performance can be promoted by regulating the diffusion behavior of the electrolyte and constructing a coupled interaction at heterogeneous interfaces. Herein, we have synthesized ultrathin NiO nanosheets anchored to nitrogen-doped hierarchical porous carbon (NiO/N-HPC) and applied it to construct aqueous potassium ion hybrid capacitors (APIHCs). The abundant and interconnected porous architecture promotes electrolyte penetration/diffusion and shortens the ion transport path, thereby accelerating storage reaction kinetics. The nitrogen-doped carbon support can achieve optimized metal oxides–carbon interaction and enhance the adsorption ability for the electrolyte ions, leading to earning higher storage capacity. Consequently, the prepared NiO/N-HPC exhibits a superior capacitance of 126.4 F g−1 at a current density of 0.5 A g−1, and the as-fabricated NiO/N-HPC//N-HPC APIHC achieves an ultra-high capacitance retention of 91.6% over 8000 cycles at a current density of 2 A g−1. Meanwhile, the APIHC device shows an excellent energy density of 21.95 W h kg−1 and a power density of 9000 W kg−1. [ABSTRACT FROM AUTHOR]

Cancer is most frequently treated with antineoplastic agents (ANAs) that are hazardous to patients undergoing chemotherapy and the healthcare workers who handle ANAs in the course of their duties. All aspects related to hazardous oncological drugs illustrate that the monitoring of ANAs is essential to minimize the risks associated with these drugs. Among all analytical techniques used to test ANAs, electrochemistry holds an important position. This review, for the first time, comprehensively describes the progress done in electrochemistry of ANAs by means of a variety of bare or modified (bio)sensors over the last four decades (in the period of 1982–2021). Attention is paid not only to the development of electrochemical sensing protocols of ANAs in various biological, environmental, and pharmaceutical matrices but also to achievements of electrochemical techniques in the examination of the interactions of ANAs with deoxyribonucleic acid (DNA), carcinogenic cells, biomimetic membranes, peptides, and enzymes. Other aspects, including the enantiopurity studies, differentiation between single-stranded and double-stranded DNA without using any label or tag, studies on ANAs degradation, and their pharmacokinetics, by means of electrochemical techniques are also commented. Finally, concluding remarks that underline the existence of a significant niche for the basic electrochemical research that should be filled in the future are presented. [ABSTRACT FROM AUTHOR]

In New Zealand, agriculture accounts for around 50% of total gross greenhouse gas emissions, energy production and use account for 40%. Given the limited possibility of reducing methane from the agricultural sector, we focus on the shape of, and factors influencing, the energy-related emissions profile. A single framework that combines environmental input–output analysis with structural decomposition analysis is established to systematically investigate driving forces shaping energy-related greenhouse gas emissions at national and sectoral levels. Results show that emission intensity, population, and consumption volume are dominant factors influencing shifting the energy-related emissions profile from 2007 to 2013. To achieve a net-zero-carbon economy, decarbonizing the transport sector is foremost and should be given priority. Policy directed at improving energy utilization in private consumption and exports, and the adoption and utilization of advanced technology in manufacturing, would contribute to achieving emissions reduction targets. [ABSTRACT FROM AUTHOR]

The perspectives of technological advances needed for short term energetic transition are briefly reviewed and discussed critically. In particular, the technologies for the greenhouse gas emission-free production of electrical energy, its storage and transport, the production, transport, storage and use of hydrogen, and the use of biomass derived technologies are shortly and critically reviewed. Critical aspects are emphasized. The role of chemistry, and in particular materials chemistry and engineering, in short-term developments are underlined. [ABSTRACT FROM AUTHOR]

The ability of various cosolutes and cosolvents to enhance or quench solvent density fluctuations at solute–water interfaces has crucial implications on the conformational equilibrium of macromolecules such as polymers and proteins. Herein, we use an extended hydrophobic solute as a model system to study the effect of urea and methanol on the density fluctuations in the solute's solvation shell and the resulting thermodynamics. On strengthening the solute–water/cosolute repulsive interaction, we observe distinct trends in the mutual affinities between various species in, and the thermodynamic properties of, the solvation shell. These trends strongly follow the respective trends in the preferential adsorption of urea and methanol: solute–water/cosolute repulsion strengthens, urea accumulation decreases, and methanol accumulation increases. Preferential accumulation of urea is found to quench the density fluctuations around the extended solute, leading to a decrease in the compressibility of the solvation shell. In contrast, methanol accumulation enhances the density fluctuations, leading to an increase in the compressibility. The mode of action of urea and methanol seems to be strongly coupled to their hydration behavior. The observations from this simple model is discussed in relation to urea driven swelling and methanol induced collapse of some well-known thermo-responsive polymers. [ABSTRACT FROM AUTHOR]