Principal Product Research Articles

Advances in Carbon Dioxide Catalytic Conversion and Applications

To achieve the global climate goals set out in the Paris Agreement, reducing carbon dioxide (CO2) emissions and utilizing resources have become key areas of focus within international energy technology research and development. CO2 can be converted into high-value chemicals, including hydrocarbons, alcohols and hydrocarbons, through the catalytic technology. This process can potentially address environmental issues while generating economic benefits. This paper presents a review of the principal products resulting from the catalytic conversion of CO2, together with an examination of their practical applications. These include hydrogenation of olefins, light aromatics, methanol, polyols, and synthetic bioconversion technologies. The development of catalysts with high conversion and selectivity represents a key area of current research. In the future, it will be necessary to combine physical, chemical, and biological technologies to establish an engineered heterogeneous carbon sequestration technology system to achieve the efficient conversion and utilization of CO2.

Development of Neural Network Potentials for Studying Chemical Behaviors of La3+/Nd3+ Ions in Molten LiCl-KCl-CsCl in Combination with Raman Spectroscopy.

The chemistry of molten salts has attracted great research interest owing to their wide applications in diverse fields. In the pyrochemical reprocessing of spent nuclear fuel or molten salt nuclear reactors, lanthanide elements as the principal fission products bring about changes in the composition and properties of molten salts. Herein, we report a comprehensive study on the coordination chemistry of the representative trivalent lanthanide ions (La3+/Nd3+) in LiCl-KCl-CsCl using a multiscale strategy combining Raman spectroscopy, deep learning, and large-scale molecular dynamics (MD) simulations. The neural network potential (NNP)-based MD and Raman spectroscopy studies revealed that La3+/Nd3+ ions prefer to form persistent octahedron complexes with the six-coordinated species as the dominant species at high temperatures. Compared to LaCl63-, NdCl63- shows higher stability with obviously longer lifetimes in LiCl-KCl-CsCl, as confirmed by the observed stronger interaction of Nd3+-Cl- pairs. The total and partial structure factors further indicated the formation of a more stable network structure in LiCl-KCl-CsCl containing NdCl3. Besides, the temperature exerts a larger influence on the local structures of the La3+ species compared to the Nd3+ analogues. According to the potential mean force calculations, the bond dissociation energies follow the order Ln-Cl > Li-Cl > K-Cl > Cs-Cl in LiCl-KCl-CsCl-LnCl3. The NNP-based large-scale MD simulations have been verified to be an efficient and powerful way in molten salt chemistry research.

Research on the protection of intangible cultural heritage and sustainable development of city brands—Taking Jingdezhen as an example

This research aims to examine the intricate connection between the preservation of intangible cultural assets and the promotion of city brands, using Jingdezhen, known as the “Porcelain Capital” of China, as a case study. Through an exploratory investigation, the study highlighted two distinct yet significant issues: the recognition of Jingdezhen’s intangible cultural assets, encompassing folklore, rituals, traditional ceramic skills, and artwork, and the economic effects resulting from cultural tourism. The research delineates the obstacles encountered by Jingdezhen in relation to urbanization, industrialization, and globalization subsequent to its establishment as the principal production hub for Chinese blue and white porcelain. Additionally, it highlights the decline of traditional ceramic skills and expertise, as community members who relied on handicrafts for their livelihoods were affected by the closure of companies. Subsequently, it elucidates the potential prospects arising from cultural tourism and the consequential economic influence of this progress on the local economy and the community’s quality of life. The report delineates community engagement initiatives and collaborative partnerships with local enterprises, colleges, government agencies, and Jingdezhen communities to use the city’s abundant cultural legacy. This research provides a comprehensive overview and assessment of the most effective methods, as identified by international studies, for incorporating the safeguarding of intangible cultural assets into sustainable urban development. Concisely, the paper offers guidance to stakeholders, the local administration, and its legislators. The statement emphasizes the necessity of implementing a comprehensive policy framework in Jingdezhen to safeguard its intangible cultural heritage and promote urban development. The objective is to achieve sustainable growth by leveraging the city’s cultural assets. The results serve as a benchmark for other cities and towns to use their cultural legacy in order to establish a sustainable city brand. Additionally, they make a valuable addition to the worldwide discourse on striking a balance between cultural preservation and economic development.

Value-added utilization technologies for seaweed processing waste in a circular economy: Developing a sustainable modern seaweed industry.

The global seaweed industry annually consumes approximately 600,000 tons of dried algal biomass to produce algal hydrocolloids, yet only 15-30% of this biomass is utilized, with the remaining 70-85% discarded or released as scum or wastewater during the hydrocolloid extraction process. This residual biomass is often treated as waste and not considered for further commercial use, which contradicts the principles of sustainable development. In reality, the residual algal biomass could be employed to extract additional biochemical components, such as pigments, proteins, and cellulose, and these ingredients have important application prospects in the food sector. According to the biorefinery concept, recycling various products alongside the principal product enhances overall biomass utilization. Transitioning from traditional single-product processes to multi-product biorefineries, however, raises operating costs, presenting a significant challenge. Alternatively, developing value-added utilization technologies that target seaweed waste without altering existing processes is gaining traction among industry practitioners. Current advancements include methods such as separation and extraction of residual biomass, anaerobic digestion, thermochemical conversion, enzymatic treatment, functionalized modification of algal scum, and efficient utilization through metabolic engineering. These technologies hold promise for converting seaweed waste into alternative proteins, dietary supplements, and bioplastics for food packaging. Combining multiple technologies may offer the most effective strategy for future seaweed waste treatment. Nonetheless, most research on value-added waste utilization remains at the laboratory scale, necessitating further investigation at pilot and commercial scales.

OH radical initiated oxidative degradation of imidacloprid in the environment: An assessment of breakdown kinetics and environmental hazards

Imidacloprid (IMI) is a common neonicotinoid pesticide that acts via a similar mechanism of action to nicotine, a naturally occurring insecticide. It is therefore important to understand its chemical fate in the environment. Hydroxyl radicals (HO) are significant oxidizing species in natural aquifers due to their strong reactivity towards organic substrates. Therefore, principal photo-oxidation products are expected to form with the involvement of HO in the self-cleaning process of water in nature. Here quantum chemical calculations are used to examine the reaction of IMI with HO in the atmosphere and aqueous environments. It was found that the principal mechanism of the HO + IMI reaction is the hydrogen transfer that, in a two-step process, produces stable cations in the gas phase. Within the atmospheric temperature range of 253–323 K, the overall rate constants for the HO + IMI reaction decreased from 4.35 × 1010 to 2.13 × 1010 M−1 s−1. Consequently, IMI can undergo rapid gaseous degradation within a comparatively brief period of 2.81 × 10−4 – 5.75 × 10−4 years. However, differences in environmental temperature and pH in aqueous environments influence the processes, rate constants, and products of IMI breakdown by the HO radical. The data indicate that IMI breakdown by OH radicals is strongly temperature and pH-dependent, resulting in the generation of different reaction products. The results imply that at all pH levels, the interaction between IMI and the ambient HO radical in water produces toxic chemical species. According to the computed data, it appears that IMI and the vast majority of degradation products present potentially carcinogenic and/or mutagenic hazards, and they also lack downstream biodegradability.

Comparison and mechanism analysis of MgO, CaO, and Portland cement for immobilization of heavy metals in MSWI fly ash

The significant production of municipal solid waste incineration fly ash (MSWI FA) underscores the importance of developing efficient solidification materials. This study employed MgO and CaO for immobilizing MSWI FA (with a 70% fly ash incorporation), and the immobilization effect was compared with that of Portland cement (PC). Experimental findings revealed that MgO exhibited the most effective stabilization for heavy metals (Cd, Cu, Pb, and Zn) compared to CaO and PC. XRD, FTIR, TG, and SEM analysis indicated that the principal hydration products in MSWI FA binders solidified with MgO, CaO, and PC were Mg(OH)2, CaCO3, and C-S-H gel, respectively. Mg(OH)2 efficiently immobilized heavy metals through chemical complexation and surface adsorption mechanisms. The MgO-treated MSWI FA demonstrated the highest residual fractions and the lowest easily leachable fractions. Moreover, the leaching characteristics of heavy metals were significantly influenced by the pH level, so MgO-treated MSWI FA with a leachate pH of 9.18 achieved the precipitation and stabilization of most heavy metals. In summary, this study provided an effective material selection for MSWI FA immobilization and presented a novel strategy for MSWI FA management.

An insight on the mechanism of the Hoppe-Seyler test for xanthine

Being xanthine an important biomolecule, it has attracted the attention of scholars from different points of view. In the analytical field some tests for identification have been developed. Hoppe-Seyler detected xanthine using calcium chlorohypochlorite and sodium hydroxide since a green ring, changing to brown, is formed. It is a challenge to the theoretical chemist disentangle what is happening at molecular level during the assay. In this communication emphasis is placed in a reactive tri-polar intermediate that arises in a reaction sequence. That is, a carboxylate and a newly formed zwitterion. Reaction with water can eliminate the last dipole (a negatively charged nitrogen and a carbonium ion). However, there is other pair of ions that are connected: the carboxylate and the carbonium ion at β-position. This situation produces immediate decarboxylation, eliminating two electrical charges in a single internal way, and forming a double bond. Neutralization of the negatively charged nitrogen atom gives an ureido. This reaction sequence produces the principal reaction product, imidazo-imidazolone. The observed colours are due to halochromism.

Modification of magnesium phosphate cement with steel slag powder and ground blast furnace slag: Mechanism of hydration and electrical conductivity

This paper delves into the impacts of steel slag powder (SSP) and ground granulated blast furnace slag (GBFS) on the workability, compressive strength, conductivity, and microstructural characteristics of magnesium phosphate cement (MPC). The findings reveal that the incorporation of mineral admixtures ranging from 10 % to 30 % enhances the fluidity of MPC. Despite a slight reduction in the 28d compressive strength of MPC with the inclusion of SSP and GBFS, there is a significant reduction in raw material costs. A notable presence of unreacted MgO, with struvite identified as the principal hydration product. Furthermore, the interaction of SSP, GBFS, and MgO with ADP yielded a dense compound that bolstered the mechanical attributes of MPC. The modified MPC exhibits diminished resistance and markedly enhanced conductivity, suggesting promising applications as an energy storage material. This research introduces an innovative approach to cost reduction in MPC, recycles industrial by-products, and promises to enable the application of MPC in the field of electrode materials for energy storage.

Additional considerations in cancer cell radioresistance, integrin αvβ3 and thyroid hormones

ABSTRACT Background The existence of a functional relationship between a certain thyroid hormone analogue and cancer cell radioresistance has been shown by Leith and coworkers. The hormone analogue with relevance to malignant cells’ radioresistance is tetraiodothyroacetic acid (tetrac). Tetrac is the deaminated derivative of L-thyroxine (T4), the principal product of the thyroid gland. Preclinical studies demonstrated that tetrac and chemically modified tetrac (CMT), e.g. a fluorobenzyl-conjugated tetrac analogue, restores radiosensitivity in certain radioresistant tumor cells. Due to their molecular, physico-chemical, and biological properties, actions of CMT analogues are believed to be initiated at the thyroid hormone analogue receptor site on plasma membrane integrin αvβ3. Objective To explore possible molecular mechanisms of the potentially therapeutically beneficial effect of CMT on cancer cells’ sensitivity to radiation, we analyzed actions of CMT analogues on expression of selected sets of genes that have been previously implicated in radioresistance of malignant cells. Discussion and conclusions In the current study, we report that genome-wide gene expression profiling analysis of human glioblastoma (GBM) and acute myelocytic leukemia (AML) cell lines exposed in vitro to noncytotoxic doses of CMT has identified decreased expression of discrete trios of genes each of which was previously linked to cancer cells’ radioresistance. Following the CMT treatment in AML cells, expression of PARP9, PARP15 and STAT3 genes was significantly reduced, while in GBM cells, expression of PRKDC, EGFR and CCNDI was significantly decreased by the drug. Notably, a broader spectrum of genes implicated in cancer cells’ radioresistance was observed in primary patient-derived GBM cells after the CMT treatment. Extensive additional experimental and clinical studies are indicated, including analyses of individual patient tumor genomics and of an array of different tumor types to define the sub-sets of tumors manifesting radioresistance in which tetrac-based agents may be expected to enhance therapeutic effects of radiation.

Epigallocatechin-3-gallate mitigates cadmium-induced intestinal damage through modulation of the microbiota-tryptophan-aryl hydrocarbon receptor pathway

Early studies have shown that the gut microbiota is a critical target during cadmium exposure. The prebiotic activity of epigallocatechin-3-gallate (EGCG) plays an essential role in treating intestinal inflammation and damage. However, the exact intestinal barrier protection mechanism of EGCG against cadmium exposure remains unclear. In this experiment, four-week-old mice were exposed to cadmium (5 mg kg−1) for four weeks. Through 16 S rDNA analysis, we found that cadmium disrupted the gut microbiota and inhibited the indole metabolism pathway of tryptophan (TRP), which serves as the principal microbial production route for endogenous ligands to activate the aryl hydrocarbon receptor (AhR). Additionally, cadmium downregulated the intestinal AhR signaling pathway and harmed the intestinal barrier function. Treatment with EGCG (20 mg kg−1) and the AhR agonist 6-Formylindolo[3,2-b] carbazole (FICZ) (1 μg/d) significantly activated the AhR pathway and alleviated intestinal barrier injury. Notably, EGCG partially restored the gut microbiota and upregulated the TRP-indole metabolism pathway to increase the level of indole-related AhR agonists. Our findings demonstrate that cadmium dysregulates common gut microbiota to disrupt TRP metabolism, impairing the AhR signaling pathway and intestinal barrier. EGCG reduces cadmium-induced intestinal functional impairment by intervening in the intestinal microbiota to metabolize AhR agonists. This study offers insights into the toxic mechanisms of environmental cadmium and a potential mechanism to protect the intestinal barrier with EGCG.

Biogeography and diversity patterns of abundant and rare bacterial communities in paddy soils along middle and lower Yangtze River.

The middle and lower reaches of the Yangtze River serve as principal rice production bases in China, yet the biodiversity and ecological processes of bacterial communities in paddy soils are not well understood. This study explores the diversity, composition, ecological function, and assembly processes of abundant and rare bacterial communities in paddy soils. A total of 129 paddy soil samples from 43 sites along the middle and lower reaches of the Yangtze River were collected and analyzed using NovaSeq sequencing. The results showed that the dominant phylum for both abundant and rare taxa was Proteobacteria, with a greater relative abundance of the abundant taxa. The diversity of the abundant community was lower than that of the rare community. Soil properties and geographic variables explained more of the variation in the abundant community than in the rare community. The rare community exhibited a significant distance-decay relationship. The assembly of the abundant community was more influenced by stochastic processes, although both the abundant and rare communities were governed by stochastic processes. It is concluded that both abundant and rare bacterial communities exhibit differing biogeographic patterns, yet they undergo similar ecological processes in the paddy soils along the middle and lower reaches of the Yangtze River. These observations offer a theoretical framework for a deeper comprehension of the function of both abundant and rare bacteria, as well as the development and preservation of soil bacterial diversity within agricultural ecosystems.

Whole-cell selective oxidation of 5-HMF by sugarcane bagasse isolated Bacillus nitratireducens

This study delves into the biocatalytic oxidation of 5-hydroxymethylfurfural (5-HMF) by the newly isolated Bacillus nitratireducens, from sugar cane bagasse. This reaction remains unexplored within the existing scientific literature concerning this microbial strain. Initially, to comprehensively characterize the strain and classify it taxonomically, genotypic and phenotypic analysis were conducted, including whole genome sequencing and ANI analysis. Subsequently, the study proceeded to evaluate for the first time with B. nitratireducens the efficiency of 5-HMF oxidation under aerobic conditions. The process resulted in the formation of 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) as the principal product, a valuable molecule that demonstrates promising potential as a precursor for polyesters. Additionally, the compound exhibits medical applications, including its role as an anti-tumor agent and interleukin inhibitor. Employing Response Surface Methodology (RSM), the conditions conducive to optimizing HMFCA production were assessed. These conditions, including a 3 mM 5-HMF concentration, a pH level of 5.6, and a temperature of 30 °C maintained over a period of 24 h, were found to yield optimal results. Model validation further underscored the effectiveness of these conditions, demonstrating a 91% HMFCA yield, which slightly exceeded the predicted 88%. In conclusion, the study highlights the potential of the biomass-derived Bacillus strain in achieving a high conversion rate through the selective oxidation of the aldehyde group present in the 5-HMF molecule. This whole-cell catalytic process eliminates the need for noble metal catalysts, commonly employed in similar chemical reactions, thereby underscoring its potential for enhancing environmental sustainability and reducing reliance on costly and potentially harmful catalysts.

Molecular insight into the structural and mechanical properties of Ca-based geopolymers

Ca-based geopolymers are a principal product of introducing calcium into geopolymers. Analyzing Ca-based geopolymers structural and mechanical properties aids in optimizing mix design of geopolymers. In this paper, partially reacted low-polymerization and fully reacted high-polymerization models were constructed to examine the structural and mechanical properties of Ca-based geopolymers with varying calcium contents via molecular dynamics simulations. Results show that Ca-based geopolymers contain pentacoordinate aluminum and tricluster oxygen which is more brittle and makes the structure loose. In low-polymerization models, an increase in calcium content accelerates the polymerization rate by overcoming the low-temperature reaction barrier. However, calcium content hinders the formation of pentacoordinate aluminum, decreasing the final degree of polymerization, resulting in weakened mechanical properties. In high-polymerization models, increased calcium decreases tricluster oxygen content, resulting in improved mechanical properties. While the hydrolysis reaction reduces mechanical properties, the weakening effect of water is greater than the enhancing effect of calcium.

Mechanical properties and water resistance study of basic magnesium sulfate cement-emulsified asphalt composite materials

This study introduces a novel semi-flexible composite material (BMSC-EA), formed by merging the favorable properties of emulsified asphalt (EA), known for its high flexibility and crack resistance, with basic magnesium sulfate cement (BMSC), recognized for its high rigidity, early strength, and toughness. The research systematically explores the impact of varying EA dosages on BMSC properties. Furthermore, the study analyzes the phase composition, pore structure, and microstructure of BMSC-EA materials. Results indicate that an increase in EA dosage leads to a corresponding extension in the setting time of BMSC, accompanied by a gradual decrease in compressive and flexural properties. Interestingly, the flexural compression ratio of BMSC increases, suggesting that EA addition significantly enhances BMSC toughness. The principal hydration product of BMSC comprised crystals of 5Mg(OH)2∙MgSO4∙7 H2O (5∙1∙7 phase). However, the introduction of EA exerted an inhibitory influence on the generation of Mg(OH)2, leading to a scenario where more MgO remained uninvolved in the hydration reaction. The porosity of the BMSC matrix increases with higher EA content. After subjecting the BMSC-EA material to water immersion treatment, a noteworthy observation emerged: exceptional water resistance was evident when the EA dosage reached 10%. This phenomenon was primarily ascribed to the heightened densification (ultrasonic velocity) observed in the BMSC-EA samples under these conditions. Additionally, the study observes further growth of Mg(OH)2 in BMSC after water immersion treatment, but excessive Mg(OH)2 negatively impacts BMSC-EA. These findings serve as both experimental and theoretical foundations for advancing innovative semi-flexible composite pavement materials.

Ozonolysis of 2-Methyl-2-pentenal: New Insights from Master Equation Modeling.

Experimental and theoretical studies were carried out to investigate the ozonolysis of trans-2-methyl-2-pentenal. The experiments were conducted in atmospheric simulation chambers coupled to a Fourier transform infrared (FTIR) spectrometer and a gas chromatograph-mass spectrometer at room temperature and atmospheric pressure in the presence of an excess of cyclohexane in dry conditions (RH < 1%). The ozonolysis reaction was investigated theoretically from the results of accurate density functional (M06-2X) and ab initio [CCSD(T)] computations, employing the AVTZ basis set. The sequence of reaction steps was established, and the system of kinetics equations was modeled using MESMER. In the first step, a primary ozonide is formed, which then decomposes along two pathways. The principal ozonolysis products are propanal, methylglyoxal, ethylformate, and a secondary ozonide. An interesting competition between sequential reaction steps and well-skipping is found, which leads to an inversion of the expected methylglyoxal/propanal product ratio at temperatures below 210 K. The mechanism of the "hot ester" reaction channel of the Criegee intermediate was revisited. The computed ozonolysis rate constant and product branching ratio are in excellent agreement with the experimental data that are also reported in the present work.

Hybrid mesoporous electrodes evidence CISS effect on water oxidation.

Controlling product selectivity is essential for improving the efficiency of multi-product reactions. Electrochemical water oxidation is a reaction of main importance in different applications, e.g., renewable energy schemes and environmental protection, where H2O2 and O2 are the two principal products. In this Communication, the product selectivity of electrochemical water oxidation was controlled by making use of the chiral induced spin selectivity (CISS) effect at mesoporous-TiO2 on the molecule-modified Au substrate. Our results show a decrease in H2O2 formation when using chiral hetero-helicene molecules adsorbed on the Au substrate. We propose a mechanism for this kinetic effect based on the onset of CISS-induced spin polarization on the Au-helicene chiral interface. We also present a new tunable substrate to investigate the CISS mechanism.

The Renin-Angiotensin System (RAS) in COVID-19 Disease: Where We Are 3 Years after the Beginning of the Pandemic.

The RAS is a hormonal system playing a pivotal role in the control of blood pressure and electrolyte homeostasis, the alteration of which is associated with different pathologies, including acute respiratory distress syndrome (ARDS). As such, it is not surprising that a number of studies have attempted to elucidate the role and balance of the renin-angiotensin system (RAS) in COVID-19. In this review article, we will describe the evidence collected regarding the two main enzymes of the RAS (i.e., ACE and ACE2) and their principal molecular products (i.e., AngII and Ang1-7) in SARS-CoV-2 infection, with the overarching goal of drawing conclusions on their possible role as clinical markers in association with disease severity, progression, and outcome. Moreover, we will bring into the picture new experimental data regarding the systemic activity of ACE and ACE2 as well as the concentration of AngII and Ang1-7 in a cohort of 47 COVID-19 patients hospitalized at the IRCCS Sacro Cuore-Don Calabria Hospital (Negrar, Italy) between March and April 2020. Finally, we will discuss the possibility of considering this systemic pathway as a clinical marker for COVID-19.

Prediction of Base-Catalyzed Hydrolysis Kinetics of Polychlorinated Dibenzo-p-Dioxins by Density Functional Theory Calculations.

Polychlorinated dibenzo-p-dioxins (PCDDs), comprising 75 congeners, have gained considerable attention from the general public and the scientific community owing to their high toxic potential. The base-catalyzed hydrolysis of PCDDs is crucial for the assessment of their environmental persistence. Nonetheless, owing to the substantial number of congeners and low hydrolysis rates of PCDDs, conducting hydrolysis experiments proves to be exceedingly time-consuming and financially burdensome. Herein, density functional theory and transition state theory were employed to predict the base-catalyzed hydrolysis of PCDDs in aquatic environments. Findings reveal that PCDDs undergo base-catalyzed hydrolysis in aquatic environments with two competing pathways: prevailing dioxin ring-opening and reduced reactivity in the hydrolytic dechlorination pathway. The resultant minor products include hydroxylated PCDDs, which exhibit thermodynamic stability surpassing that of the principal product, chlorinated hydroxydiphenyl ethers. The half-lives (ranging from 17.10 to 1.33 × 1010 h at pH = 8) associated with the base-catalyzed hydrolysis of PCDDs dissolved in water were shorter compared to those within the water-sediment environmental system. This observation implies that hydroxide ions can protect aquatic environments from PCDD contamination. Notably, this study represents the first attempt to predict the base-catalyzed hydrolysis of PCDDs by using quantum chemical methods.

Theoretical study on the effect of oxidation states of phosphorus flame retardants on their mode of action

Polymers are ubiquitous and find applications in various facets of daily life and industrial production. However, the fire incidents induced by polymers jeopardize the safety of human life and property. Improving the fire resistance of polymeric materials through halogen-free flame retardants has become a prominent direction guided by the regulatory framework. In this paper, the decomposition pathways and mechanisms of five phosphorus-containing flame retardants, PPh3, DPPO, PDPP, TPPO and TPP, were investigated. The reaction pathways primarily encompassed the generation of PO, PO2, PO3, PO4, phenyl, and phenoxy radicals. Through a comprehensive analysis of the dissociation energies of P-C, P-O, and CO bonds under diverse chemical environments, phenoxy radicals was the principal decomposition products, with the cleavage of P-O bonds being the predominant choice. Increasing phosphorus oxidation states favors the accumulation of a carbon layer, tending to retard flame propagation through condensed-phase mechanisms. Phosphorus oxidation states primarily facilitated secondary dissociation reactions. The presence of oxygen favored the cleavage of P-C bonds, offering diverse flame retardant mechanisms that concurrently mitigated flame spread. This work provided an in-depth exploration of the flame retardant mechanisms of phosphorus-containing agents and summarized the impact of phosphorus oxidation states on flame retardants.

Spatial Patterns and the Evolution of Logistics Service Node Facilities in Large Cities—A Case from Wuhan

Logistics services are integral to urban economic activity, and delving into the spatial distribution traits and evolutionary pathways of various kinds of logistics service node facilities (LSNF) is markedly valuable for understanding a city’s functional spatial makeup and refining the spatial layout of logistics services. This study quantitatively and qualitatively analyzes the spatial congregation and spreading characteristics of diverse LSNFs in Wuhan in 2011, 2014, 2017, and 2020, employing kernel density analysis, average nearest neighbor index, mean center, and distance distribution frequency, seeking to characterize the spatial evolution characteristics of LSNF, alongside examining the trends in distances to city cores, principal adjoining roads, and production and consumption sites. The following conclusions were made: (1) Between 2011 and 2020, various types of LSNFs in Wuhan experienced a pattern characterized by the noticeable coexistence of spatial expansion and agglomeration, particularly visible after 2014. The degree of agglomeration is classified in a descending order as follows: CWC, STN, PSN, and PDN. (2) An “absolute diffusion” phenomenon characterizes the distribution of distances between various kinds of LSNFs and city cores or neighboring roads, with the lion’s share of high-frequency distribution zones spreading beyond city cores by 5–10 km, and a majority of the LSNFs being situated within 1 km from adjacent roads. (3) While the LSNF collective exhibits a stronger tendency towards the consumption facet, it reflects a surrounding of industrial production sites on the production facet and locations of manufactured goods consumption on the consumption facet, followed by locations of agricultural product consumption and comprehensive consumption sites.