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Improving the catalytic performance of materials based on cerium oxide (CeO2) for the activation of methane (CH4) can be achieved through the following strategies: mixture of CeO2 with different oxides (e.g., CeO2–La2O3) and the use of particles with different sizes. In this study, we present a theoretical investigation of the initial CH4 dehydrogenation on (La2Ce2O7)n clusters, where n = 2, 4, and 6. Our framework relies on density functional theory calculations combined with the unity bond index–quadratic exponential potential approximation. Our results indicate that chemical species arising from the first dehydrogenation of CH4, that is, CH3 and H, bind through the formation of C–O and H–O bonds with the clusters, respectively. The coordination of the adsorption site and the chemical environment plays a crucial role in the magnitude of the adsorption energy; for example, species adsorb more strongly in the low-coordinated topO sites located close to the La atoms. Thus, it affects the activation energy barrier, which tends to be lower in configurations where the adsorption of the chemical species is stronger. During CH4 dehydrogenation, the CH3 radical can be present in a planar or tetrahedral configuration. Its conformation changes as a function of the charge transference between the molecule and the cluster, which depends on the CH3-cluster distance. Finally, we analyze the effects of the Hubbard effective parameter (Ueff) on adsorption properties, as the magnitude of localization of Ce f-states affects the hybridization of the interaction between the molecule and the clusters and hence the magnitude of the adsorption energies. We obtained a linear decrease in the adsorption energies by increasing the Ueff parameter; however, the activation energy is only slightly affected. [ABSTRACT FROM AUTHOR]

The spur reaction, a spatially nonhomogeneous chemical reaction following ionization, is crucial in radiolysis or photolysis in liquids, but the spur expansion process has yet to be elucidated. One reason is the need to understand the role of the dielectric response of the solvating molecules surrounding the charged species generated by ionization. The dielectric response corresponds to the time evolution of the permittivity and might affect the chemical reaction–diffusion of the species in a spur expansion process. This study examined the competitive relationship between reaction–diffusion kinetics and the dielectric response by solving the Debye–Smoluchowski equation while considering the dielectric response. The Coulomb force between the charged species gradually decreases with the dielectric response. Our calculation results found a condition where fast recombination occurs before the dielectric response is complete. Although it has been reported that the primary G-values of free electrons depend on the static dielectric constant under low-linear-energy transfer radiation-induced ionization, we propose that considering the dielectric response can provide a deeper insight into fast recombination reactions under high-linear-energy transfer radiation- or photo-induced ionization. Our simulation method enables the understanding of fast radiation-induced phenomena in liquids. [ABSTRACT FROM AUTHOR]

As investigations in the biomedical applications of plasma advance, a demand for describing safe and efficacious delivery of plasma is emerging. It is quite clear that not all plasmas are "equal" for all applications. This Perspective discusses limitations of the existing parameters used to define plasma in context of the need for the "right plasma" at the "right dose" for each "disease system." The validity of results extrapolated from in vitro studies to preclinical and clinical applications is discussed. We make a case for studying the whole system as a single unit, in situ. Furthermore, we argue that while plasma-generated chemical species are the proposed key effectors in biological systems, the contribution of physical effectors (electric fields, surface charging, dielectric properties of target, changes in gap electric fields, etc.) must not be ignored. [ABSTRACT FROM AUTHOR]

Chemical reaction networks can undergo nonequilibrium phase transitions upon variation in external control parameters, such as the chemical potential of a species. We investigate the flux in the associated chemostats that is proportional to the entropy production and its critical fluctuations within the Schlögl model. Numerical simulations show that the corresponding diffusion coefficient diverges at the critical point as a function of system size. In the vicinity of the critical point, the diffusion coefficient follows a scaling form. We develop an analytical approach based on the chemical Langevin equation and van Kampen's system size expansion that yields the corresponding exponents in the monostable regime. In the bistable regime, we rely on a two-state approximation in order to analytically describe the critical behavior. [ABSTRACT FROM AUTHOR]

Chemical reactions can induce Marangoni flows by changing the surface tension of a solution open to the air, either by changing the composition and/or by modifying the temperature. We consider the case of a simple A + B → C reaction front propagating in a thin horizontal system open to air. The effect of the three chemical species on the surface tension of the aqueous solution is quantified by three solutal Marangoni numbers, while the effect of temperature changes is determined by the thermal Marangoni number. By integrating numerically the incompressible Navier–Stokes equations coupled to reaction-diffusion-convection equations for the chemical concentrations and temperature taking into account the Lewis number (ratio between heat and mass diffusivities), we emphasize the importance of thermal changes occurring due to the heat of reaction on the dynamics of chemically induced Marangoni convection. Based on the reaction-diffusion profiles of concentrations and temperature, asymptotic analytical solutions for the surface tension profiles are obtained and classified as a function of the Marangoni numbers and the Lewis number. This new classification allows for the prediction of the convective patterns in thermo-solutal Marangoni flows. The analytical predictions are further confirmed by numerical results and additional extrema in surface tension profiles induced by the thermal effects are found to affect the nonlinear dynamics. [ABSTRACT FROM AUTHOR]

The importance of nitrate and ammonium salts both in the environment and in biological processes cannot be questioned. In this work, using the TIP4P/2005 water model, aqueous solutions of nitrate and ammonium electrolytes are parametrized using scaled charges while keeping a rigid structure and nonpolarizable charge distributions. The models are optimized by systematically testing a set of properties for twelve electrolytes—eight nitrate and four ammonium salts—thus, enlarging the number of potential chemical species encompassed within the Madrid-2019 force field for ions. The capacity of the force field for predicting densities, ion–ion and ion–solvent structures, and transport properties of the solutions comprised by the trial batch of salts was tested and discussed. Both the dependence of the densities with the salt concentration and the solution structure were nicely reproduced by the models in the whole concentration range without any trace of precipitating events and with improved accuracy in comparison with recently reported models, while the agreement of the simulated transport properties with experimental data ranges from good to reasonable, depending on the ion/counterion pair. These scaled charge models might be considered as force fields embodying a reasonable compromise between exactness and general applicability and also as an important step in the development of accurate models for polyatomic ions. [ABSTRACT FROM AUTHOR]

The temperature dependence of the nuclear free induction decay in the presence of a magnetic-field gradient was found to exhibit motional narrowing in gases upon heating, a behavior that is opposite to that observed in liquids. This has led to the revision of the theoretical framework to include a more detailed description of particle trajectories since decoherence mechanisms depend on histories. In the case of free diffusion and single components, the new model yields the correct temperature trends. The inclusion of boundaries in the current formalism is not straightforward. We present a hybrid SDE-MD (stochastic differential equation - molecular dynamics) approach whereby MD is used to compute an effective viscosity and the latter is fed to the SDE to predict the line shape. The theory is in agreement with the experiments. This two-scale approach, which bridges the gap between short (molecular collisions) and long (nuclear induction) timescales, paves the way for the modeling of complex environments with boundaries, mixtures of chemical species, and intermolecular potentials. [ABSTRACT FROM AUTHOR]

The ion–molecule reaction is one of the most important pathways for the formation of new interstellar chemical species. Herein, infrared spectra of cationic binary clusters of acrylonitrile (AN) with methanethiol (CH3SH) and dimethyl sulfide (CH3SCH3) are measured and compared to those previous studies of AN and methanol (CH3OH) or dimethyl ether (CH3OCH3). The results suggest that the ion–molecular reactions of AN with CH3SH and CH3SCH3 only yield products with S...HN H-bonded or S∴N hemibond structures, rather than the cyclic products as observed in AN-CH3OH and AN-CH3OCH3 studied previously. The Michael addition-cyclization reaction between acrylonitrile and sulfur-containing molecules does not occur due to the weaker acidity of CH bonds in sulfur-containing molecules, which results from their weaker hyperconjugation effect compared to oxygen-containing molecules. The reduced propensity for the proton transfer from the CH bonds hinders the formation of the Michael addition-cyclization product that follows. [ABSTRACT FROM AUTHOR]

The underwater streamer discharges have a variety of potential applications in environmental science and technology. The electrical characteristics of the plasma filament generated by underwater streamer discharges play an important role in its propagation through water and influence the production of the chemical reactive species and the energy injected into the plasma filament. In this paper, we studied the electric field inside the plasma filament, the electric field at the head of the plasma filament, and the electrical conductivity of the plasma filament. By measuring the maximum length and the radius of the plasma filament, we found that the linear relation between the maximum length of the plasma filament and the applied voltage is not affected by the water conductivity within the range of 60–540 μS/cm. Based on such kind of linear relation, the electric field inside the plasma filament and the electric field at the head of the plasma filament were estimated as 26.0 ± 1.2 and 372 ± 52 kV/cm on average, respectively, being independent of the water conductivity within the range of 60–540 μS/cm. The electrical conductivity of the plasma filament was 0.4–3.7 S/cm within the range studied, being 3–4 orders of magnitude greater than that of the ambient water and depending significantly on the water conductivity. The experimental data obtained in the present work will be beneficial for the design of the reactor of pulsed underwater discharges. [ABSTRACT FROM AUTHOR]

The ion–molecule reaction is one of the most important pathways for the formation of new interstellar chemical species. Herein, infrared spectra of cationic binary clusters of acrylonitrile (AN) with methanethiol (CH3SH) and dimethyl sulfide (CH3SCH3) are measured and compared to those previous studies of AN and methanol (CH3OH) or dimethyl ether (CH3OCH3). The results suggest that the ion–molecular reactions of AN with CH3SH and CH3SCH3 only yield products with S...HN H-bonded or S∴N hemibond structures, rather than the cyclic products as observed in AN-CH3OH and AN-CH3OCH3 studied previously. The Michael addition-cyclization reaction between acrylonitrile and sulfur-containing molecules does not occur due to the weaker acidity of CH bonds in sulfur-containing molecules, which results from their weaker hyperconjugation effect compared to oxygen-containing molecules. The reduced propensity for the proton transfer from the CH bonds hinders the formation of the Michael addition-cyclization product that follows. [ABSTRACT FROM AUTHOR]

In this paper, we examine a novel generalized (2 + 1) -dimensional Bogoyavlensky–Konopelchenko (gBK) model analytically via application of five mathematical methods, namely called Extended Simple Equation (ESE) method, Modified Extended Auxiliary equation mapping (MEAEM) method, (G ′ / G) -expansion method, Exp (− Ψ (ϕ)) -expansion method and modified F-expansion method, respectively, to obtain different types solitary wave solutions in the form of trigonometric, hyperbolic, rational and exponential functions as compared to solutions exist in [S. T. Chen and W. X. Ma, Math. China 13 (2018) 525; A. Sonia, A. Jamshad, S.-U. Rehman and A. Ali, Int. J. Appl. Comput. Math. 9 (2023)]. The research focuses on physical systems, physiology, mathematical applications, engineering fields, and the chemical processes of species in the porous nanoparticles, examining the impact of various parameters on the nonlinear model. The graphs of some solutions are plotted in the form of two-dimensional and three-dimensional by assigning the particular values to the paraments with the assistance of mathematica software which illustrated the physical behavior of the concern model. The derived solution has numerous applications in fluid dynamics and the interaction of Riemann waves and long waves. [ABSTRACT FROM AUTHOR]

Understanding the diverse electrochemical reactions occurring at electrode‐electrolyte interfaces (EEIs) is a critical challenge to developing more efficient energy conversion and storage technologies. Establishing a predictive molecular‐level understanding of solid electrolyte interphases (SEIs) is challenging due to the presence of multiple intertwined chemical and electrochemical processes occurring at battery electrodes. Similarly, chemical conversions in reactive electrochemical systems are often influenced by the heterogeneous distribution of active sites, surface defects, and catalyst particle sizes. In this mini review, we highlight an emerging field of interfacial science that isolates the impact of specific chemical species by preparing precisely‐defined EEIs and visualizing the reactivity of their individual components using single‐entity characterization techniques. We highlight the broad applicability and versatility of these methods, along with current state‐of‐the‐art instrumentation and future opportunities for these approaches to address key scientific challenges related to batteries, chemical separations, and fuel cells. We establish that controlled preparation of well‐defined electrodes combined with single entity characterization will be crucial to filling key knowledge gaps and advancing the theories used to describe and predict chemical and physical processes occurring at EEIs and accelerating new materials discovery for energy applications. [ABSTRACT FROM AUTHOR]

The Earth's atmosphere is composed of an enormous variety of chemical species associated with trace gases and aerosol particles whose composition and chemistry have critical impacts on the Earth's climate, air quality, and human health. Mass spectrometry analysis as a powerful and popular analytical technique has been widely developed and applied in atmospheric chemistry for decades. Mass spectrometry allows for effective detection, identification, and quantification of a broad range of organic and inorganic chemical species with high sensitivity and resolution. In this review, we summarize recently developed mass spectrometry techniques, methods, and applications in atmospheric chemistry research in the past several years on molecular‐level. Specifically, new developments of ion‐molecule reactors, various soft ionization methods, and unique coupling with separation techniques are highlighted. The new mass spectrometry applications in laboratory studies and field measurements focused on improving the detection limits for traditional and emerging volatile organic compounds, characterizing multiphase highly oxygenated molecules, and monitoring particle bulk and surface compositions. [ABSTRACT FROM AUTHOR]

Investigating the different chemical species of soluble iron in food digests provides more relevant information on the nutritional potential of an iron‐rich food. The objective of this study was to assess the bioaccessibility and speciation of iron from various aqueous extracts of Moringa (Moringa oleifera) leaves. Aqueous extracts were prepared from fresh and dried Moringa leaves using infusion and decoction methods. Spectrophotometric assays were performed to quantify inhibitors and enhancers of iron absorption in the extracts, bioaccessible iron, and its different chemical species. The highest contents of inhibitors (239.43 mg/L for polyphenols and 2.92 mg/L for phytates) and enhancers of iron absorption (1.58 mmol/L for carotenoids and 488.00 mg/L for ascorbic acid) were found in the 5‐minute decoction extract of fresh leaves, and the lowest in all infusion extracts (27.34 mg/L for polyphenols, 0.50 mg/L for phytates, 0.15 mmol/L for carotenoids, and 86.00 mg/L for ascorbic acid). The percentages of bioaccessible iron were higher for decoction extracts (42.57–52.70%) compared to infusion extracts (33.89–36.44%). Ferrous iron was the dominant inorganic species of bioaccessible iron and was more concentrated in the digests of decoction extracts (1.32–4.85 mg/L). The highest content of organic iron (5.33 mg/L) was found in the digest of the 8‐minute decoction extract of dried leaves. Drinking decoction extracts of fresh and dried Moringa leaves could be recommended to alleviate iron deficiency in vulnerable groups of the population living in areas where this plant can grow. [ABSTRACT FROM AUTHOR]

Nanosize-controlled antimony oxides (Sb2O3) that can effectively scavenge fluoride species in a cell are incorporated into a PI separator to regulate its porous structure. The incorporation of the Sb2O3 layer onto the PI separator surface prevents the internal short circuit and efficiently removes fluoride species via chemical scavenging reactions, thereby resulting in stable cycling behaviors upon cycling. [ABSTRACT FROM AUTHOR]

Geckos stand out among lizards for communicating by means of visual, chemical, and acoustic modalities. Although these lizards are known for using these three modalities, the number of studies using them as subjects is restricted, especially those focused on the Chilean endemic genus Garthia. Here, we quantify the social behaviour of G. gaudichaudii, with special focus on the acoustic component. We also examine behaviours linked to the use of visual and chemoreceptive signals, and how these relate to acoustic signals, shedding light on the potential use of multichannel communication in this species. We examined social interactions of these lizards during encounters between pairs of non-breeding adult individuals of same or different sex. We found that both sexes emit single chirp calls of low intensity and at a low rate. Females calls preceded the approach of an interacting individual (male or female), while a single male called exclusively while ramming a female. We suggest an intimidatory functional role for these calls. Geckos also performed different visual displays, among which aggressive vertical tail-waving is followed by aggressive single chirp calls. Both sexes performed tongue-flicks, mainly to the air or to a conspecific, suggesting that vomerolfaction of volatile and non-volatile chemicals is important for chemical communication in this species. Some males performed courtship behaviours, but no copulation was recorded. Females rejected males performing tail-waving displays and made escape attempts, likely because experiments involved non-breeding subjects. Our study demonstrated that female and male G. gaudichaudii use acoustic signals coupled to various visual and chemoreceptive behaviours during social interactions. [ABSTRACT FROM AUTHOR]

Linearly dependent concentration profiles of a chemical reaction can result in a spectral data matrix with a chemical rank smaller than the number of absorbing chemical species. Such a rank deficiency is problematic for a factor analysis as some information on the pure component spectra cannot be recovered from the mixture data. Matrix augmentation can break rank deficiencies and enable successful pure component recovery. In contrast to this, an artificial breakdown of a rank deficiency can be caused by a numerical finite precision simulation of the underlying kinetic model and can fake a successful MCR analysis. This work discusses the problem and points out some remedies. Linearly dependent concentration profiles of a chemical reaction can result in a spectral data matrix with a chemical rank smaller than the number of absorbing chemical species. This work discusses such rank deficiencies and the artificial breakdown of a rank deficiency by a finite precision numerical simulation. [ABSTRACT FROM AUTHOR]

Pseudodictamnus africanus (L.) Salmaki & Siadati [previously called Ballota africana (L.) Benth.] is a well-known Cape traditional medicine in many parts of the Cape region of South Africa. Known as kattekruid , it is used to treat various ailments, including respiratory infections, pain and inflammation. To date, only a single chemical compound, hispanolone, has been identified in the species. This study reports for the first time the major volatile and non-volatile compounds of kattekruid. Using GC–MS, 52 compounds could be identified in 12 samples of essential oil, of which viridiflorol (14.22 %), β-caryophyllene (7.65 %), and caryophyllene oxide (7.41 %) were consistently present as major compounds. Using multivariate statistics, chemophenetic variation was observed amongst the 12 samples collected from four populations used in the study. For example, one population has β-bisabolene (13.09 %) as a major compound, whereas another exhibited germacrene-D (6.87 %) and sesquiabene hydrate (5.30 %). Non-volatile constituents separated using LC–MS, were tentatively identified as (3) forsythoside B, (4) verbascoside/acetoside, (5) isoverbascoside, (12) ballotenol, (13) ballotenic acid and (25) hispanolone. This exploratory study provides the foundation for further, in-depth studies on chemical variation in the species. The reported anti-inflammatory activity of some of the major volatile and non-volatile compounds provides a potential rationale for the traditional medicinal uses that have been recorded. [Display omitted] • First substantial study of volatile and non-volatile compounds. • Non-volatile compounds include forsythoside b and verbascoside. • Volatile compounds include viridiflorol, β-caryophyllene and caryophyllene oxide. • The major compounds have documented anti-inflammatory activity. • The traditional uses may be explained by the major compounds. [ABSTRACT FROM AUTHOR]

The concept of extractables and leachable has introduced a new era for identifying potential impurities in drug products. Pharmaceutical packaging materials encompass a variety of polymers due to their appealing properties for storing the drug product. However, numerous chemical species may leach into the drug product from these polymers, posing significant health hazards in the public domain. Identifying such leachable is crucial for assessing safety and addressing toxicological concerns. Acrylic acids are commonly used materials for adhering needles to the barrel in pre-filled syringes. In this study, we identified acrylic acid leachable impurities in ganirelix drug products available in the market using mass spectrometry as an analytical technique. These impurities leached into the drug product during storage conditions. Characterization of the impurities was carried out through data obtained from HRMS and MS/MS analysis, revealing them as polyacrylic acid-ganirelix adduct impurities. This study offers valuable insights into identifying leachable and susceptible sites, providing a foundation for potential modifications in similar classes of drug products, thereby enhancing their safety and efficacy. [ABSTRACT FROM AUTHOR]

The rising number of diseases and deaths caused by pollution and modern lifestyle habits is a growing societal concern. Marine ecosystems are both victim to this human behaviour as a recipient of human pollution as well as being a source of medicinal chemicals which can cure a variety of diseases. In this paper, we review the chemical basis of water-based treatments and their effects on human health, while focusing on the threats to marine ecosystems and the potential benefits of balneotherapy, thalassotherapy, and bioactive chemical species. We found that seawater has potential benefits for skin health, demonstrating emollient properties, protection against skin barrier disruption, and inhibition of atopic dermatitis-like skin lesions. We present the putative mechanisms by which minerals, salts, and marine organic matter can slow down disease progression, through their numerous activities, such as anti-inflammatory, antioxidant, and wound healing properties. Water-living organisms also have an impact on such mechanisms by producing biologically active compounds with beneficial effects on human health. [ABSTRACT FROM AUTHOR]

The performance of the perturbed‐chain statistical associating fluid theory‐type equations of state (PC‐SAFT‐type EOSs) is compromised in predicting properties of pure compounds in the critical region. In our previous research, we introduced an improved volume‐translated rescaled PC‐SAFT EOS (VTR‐PC‐SAFT EOS) by incorporating a dimensionless distance‐function. Such VTR‐PC‐SAFT EOS is built based on a critical point‐based PC‐SAFT EOS that can reproduce the critical temperature, critical pressure, and critical molar volume of pure compounds. VTR‐PC‐SAFT EOS is found to significantly improve the accuracy of phase behavior predictions in both critical and noncritical regions for pure compounds. In this study, we assess the performance of VTR‐PC‐SAFT EOS in reproducing the critical and noncritical properties of 251 pure compounds, encompassing 20 distinct chemical species. The testing results indicate that, compared to the other three PC‐SAFT‐type EOSs, the VTR‐PC‐SAFT EOS can consistently provide more accurate representations of critical and noncritical properties of 251 pure compounds. [ABSTRACT FROM AUTHOR]

The selective factors that shape phenotypic diversity in prey communities with aposematic animals are diverse and coincide with similar diversity in the strength of underlying secondary defences. However, quantitative assessments of colour pattern variation and the strength of chemical defences in assemblages of aposematic species are lacking. We quantified colour pattern diversity using quantitative colour pattern analysis (QCPA) in 13 dorid nudibranch species (Infraorder: Doridoidei) that varied in the strength of their chemical defences. We accounted for the physiological properties of a potential predator's visual system (a triggerfish, Rhinecanthus aculeatus) and modelled the appearance of nudibranchs from multiple viewing distances (2 and 10 cm). We identified distinct colour pattern properties associated with the presence and strength of chemical defences. Specifically, increases in chemical defences indicated increases in colour pattern boldness (i.e. visual contrast elicited via either or potentially coinciding chromatic, achromatic and/or spatial contrast). Colour patterns were also less variable among species with chemical defences when compared to undefended species. Our results indicate correlations between secondary defences and diverse, bold colouration while showing that chemical defences coincide with decreased colour pattern variability among species. Our study suggests that complex spatiochromatic properties of colour patterns perceived by potential predators can be used to make inferences on the presence and strength of chemical defences. [ABSTRACT FROM AUTHOR]

Episodic accretion in protostars leads to luminosity outbursts that end up heating their surroundings. This rise in temperature pushes the snow lines back, enabling the desorption of chemical species from dust grain surfaces, which may significantly alter the chemical history of the accreting envelope. However, a limited number of extensive chemical surveys of eruptive young stars have been performed thus far. In the present study, we carry out a large spectral survey of the binary Class I protostar L1551 IRS 5, known to be a FUor-like object, in the 3 mm and 2mm bands with the IRAM-30m telescope. As a result, we detected more than 400 molecular lines. The source displays a great chemical richness with the detection of 75 species, including isotopologues. Among these species, there are 13 hydrocarbons, 25 N-bearing species, 30 O-bearing species, 15 S-bearing species, 12 deuterated molecules, and a total of 10 complex organic molecules (l-C4H2, CH3CCH, CH2DCCH, CH3CHO, CH3CN, CH3OCH3, CH3OCHO, CH3OH, CH2DOH, and HC5N). With the help of local thermodynamic equilibrium (LTE) and non-LTE models, we determined the column densities of most molecules as well as excitation and kinetic temperatures. While most of those molecules trace the cold envelope (≲20 K), the OCS and CH3OH emission arise from the warm (>100 K) innermost (<2″) regions. We compared the chemical inventory of L1551 IRS 5 and its column density ratios, including isotopic ratios, with other protostellar sources. A broad chemical diversity is seen among Class I objects. More observations with both single-dish telescopes and interferometers are needed to characterize the diversity in a larger sample of protostars, while more astrochemical models would help explain this diversity, in addition to the impact of luminosity outbursts on the chemistry of protostellar envelopes. [ABSTRACT FROM AUTHOR]

Diatomic multilattices are congruences of simple lattices each made out of atoms of two possible chemical species. We here constitutively characterize, in three dimensions, diatomic multilattices for the geometrically and materially linear elastic regime. We give the most generic expression for the energy for (n + 1) diatomic multilattices and characterize explicitly the tensors present in such an expression for all 122 two-color point groups. For the specific case of diatomic 2- and 3-lattices, we delineate how one can solve the shift vector equation in the static case. For cases where the unique solution of the shift vector in terms of the strain tensor is not possible, we give conditions for the existence of solutions based on the standard Fredholm alternative theorem. [ABSTRACT FROM AUTHOR]

The peculiar behavior of arsenoplatin-1, ([Pt(µ-NHC(CH3)O)2ClAs(OH)2], AP-1), in aqueous solution and the progressive appearance of a characteristic and intense blue color led us to carry out a more extensive investigation to determine the nature of this elusive chemical species, which we named "AsPt blue". A multi-technique approach was therefore implemented to describe the processes involved in the formation of AsPt blue, and some characteristic features of this intriguing species were revealed. [ABSTRACT FROM AUTHOR]

Plasma‐facing liquids (PFLs) facilitate the storage of reactive O and N species (RONS), including H2O2 and NO2−, which remain in the PFL after plasma treatment, and they can continuously influence the target immersed in the liquid. However, their behaviors and levels of generation and extinction depend strongly on the plasma characteristics and liquid condition. Therefore, understanding the effects of the liquid type on the plasma discharge characteristics and the RONS generated via plasma discharge is necessary. We compared the RONS generation and storage trends of deionized H2O and a high‐conductivity PFL, RPMI 1640, which is a well‐known cell culture medium commonly used to culture mammalian cells. RPMI 1640 acted as an electrode and enhanced the plasma discharge power by supplying abundant radicals and RONS. The production of gaseous hydroxyl radicals and NO markedly increased, which facilitated H2O2 and NO2− production in the PFL for the first 200 s, and then the increase in the RONS concentration stagnated. With respect to storage, as the components within RMPI 1640 exhibited high reaction constants for their reactions with H2O2, H2O2 elimination was completed in <30 min. Unlike H2O2, the concentration of NO2− in the PFL was unchanged. [ABSTRACT FROM AUTHOR]

Persistent emission is a well-known property of cadmium metasilicate (CdSiO 3) doped and co-doped with rare earth ions due to the ease of choosing the desired luminescence colour, as well as the possibility of adjusting the emission colour and the luminescence duration. Experimental work has demonstrated that combinations of different rare earth ions can produce different emission spectra colours as well as modify the lifetime of emissions. Theoretical work demonstrated a preference of single dopants to substitute cadmium sites with a Cd-vacancy as a compensation mechanism. To help elucidate the luminescent mechanisms through structural modification and consequently modification of the crystal field generated in the material by the defective region, in this work, several configurations for combined defects were tested considering the distance and preferential configuration of all the defects that comprise the system, as well as the possibility of a high concentration of these defects. Results showed a preferential arrangement for the incorporation of a Cd-vacancy as a form of charge compensation. The arrangement forms an angle closer to 180° considering the Cd-vacancy as vertex and presents a distance of around 7 Å between rare earth ions. It was also identified that the formation of a single pair with two different RE3+ ions close to a cadmium vacancy are minimally energetically more favourable to be formed in relation to clusters of dopants and co-dopants. This indicates that at low doping concentrations, RE3+ dopant pairs will form separately, but by increasing the concentration it is possible to form a cluster of defects involving RE3+. This may explain the low concentrations of dopants in this matrix. The distortion caused in the local lattice by the presence of a RE3+ pair of different dopants is bigger than the distortion caused by a RE3+ pair of dopants of the same chemical species. Therefore, CdSiO 3 : RE13+, RE23+ has a crystal field that is different from the crystal field experienced by RE3+ as a single dopant and the presence of the co-dopant ion will modify the luminescence of the system even though the generating defect of the luminescent centre remains the same. [ABSTRACT FROM AUTHOR]

• We study the chemistry of the core and ocean of Enceladus based on different core compositions. • We study the hydrothermal products from the ocean-core interaction in the context of the chemistry of the plume of Enceladus. • We evaluate the chemistry of the ocean based on its possible pH values and the saturation indices of mineral products. • We find that the actual composition of the core poses a somewhat wide range of possible compositional scenarios. Measurements made by the Cassini spacecraft instruments were able to reveal the composition of the geysers of the Saturn moon, Enceladus, among which salts (sodium chloride, sodium bicarbonate and/ or sodium carbonate) and traces of silica could be the result of hydrothermal processes from the interaction of an inner liquid ocean with the core of Enceladus. The chemistry of the ocean should be closely connected to the chemistry of the core. Even though. the actual composition of the core is unknown, Enceladus has been characterised as a moon with a silicate core and different authors have estimated the properties of the ocean. A core with a silicate composition alone, does not necessarily justify most of the observed species of the plume. Given the many uncertainties, in the current work, we study the possible chemistry of the core and the ocean in the context of a four-layered Enceladus (dry core, hydrated core, ocean and crust) with three different compositional scenarios for the core: primordial (represented by an ordinary chondrite), composite (represented by a carbonaceous chondrite with an igneous inclusion) and non primordial (epresented by a given peridotite). The scenarios comprise a set of minerals that interact with a primordial ocean (either pure or enriched water) at a given temperature and pressure, producing a series of secondary minerals and compounds, some of them, coincident with the chemical species observed in the geysers. Specifically, we make a chemical speciation for each proposed compositional scenario with the software PhreeqC, however our analysis is limited to the study of interactions that reach a given equilibrium. In particular, output values like the potential of hydrogen of the ocean or the saturation indices of mineral products may give us hints about the chemistry of the ocean and the core. We find that, based on the species observed in the plume, the actual composition of the core (and the ocean as well) poses a somewhat wide range of possible compositional scenarios and each of our proposed scenarios and their products justify, to some extent, the observations of the plume. [ABSTRACT FROM AUTHOR]

Emerging pollutants in the environment due to economic development have become a global challenge for environmental and human health management. The presence of metals which exploited for various industrial and economic purposes in the environment is a major cause of pollution. Potentially toxic elements, a major group of pollutants, have been detected in soil, air, water and food crops. Pollution with metals is a serious problem worldwide due to their toxicity and non-biodegradability and ability to accumulate in the environment and living organisms. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. In the presented article, the impact of heavy metals on the environment and living organisms was considered. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are found in many consumer and industrial products. While some PFAS, notably perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), are developmentally toxic in mammals, the vast majority of PFAS have not been evaluated for developmental toxicity potential. A concentration–response study of 182 unique PFAS chemicals using the zebrafish medium-throughput, developmental vertebrate toxicity assay was conducted to investigate chemical structural identifiers for toxicity. Embryos were exposed to each PFAS compound (≤100 μM) beginning on the day of fertilization. At 6 days post-fertilization (dpf), two independent observers graded developmental landmarks for each larva (e.g., mortality, hatching, swim bladder inflation, edema, abnormal spine/tail, or craniofacial structure). Thirty percent of the PFAS were developmentally toxic, but there was no enrichment of any OECD structural category. PFOS was developmentally toxic (benchmark concentration [BMC] = 7.48 μM); however, other chemicals were more potent: perfluorooctanesulfonamide (PFOSA), N-methylperfluorooctane sulfonamide (N-MeFOSA), ((perfluorooctyl)ethyl)phosphonic acid, perfluoro-3,6,9-trioxatridecanoic acid, and perfluorohexane sulfonamide. The developmental toxicity profile for these more potent PFAS is largely unexplored in mammals and other species. Based on these zebrafish developmental toxicity results, additional screening may be warranted to understand the toxicity profile of these chemicals in other species. [ABSTRACT FROM AUTHOR]

Biology is perhaps the most complex of the sciences, given the incredible variety of chemical species that are interconnected in spatial and temporal pathways that are daunting to understand. Their interconnections lead to emergent properties such as memory, consciousness, and recognition of self and non‐self. To understand how these interconnected reactions lead to cellular life characterized by activation, inhibition, regulation, homeostasis, and adaptation, computational analyses and simulations are essential, a fact recognized by the biological communities. At the same time, students struggle to understand and apply binding and kinetic analyses for the simplest reactions such as the irreversible first‐order conversion of a single reactant to a product. This likely results from cognitive difficulties in combining structural, chemical, mathematical, and textual descriptions of binding and catalytic reactions. To help students better understand dynamic reactions and their analyses, we have introduced two kinds of interactive graphs and simulations into the online educational resource, Fundamentals of Biochemistry, a LibreText biochemistry book. One is available for simple binding and kinetic reactions. The other displays progress curves (concentrations vs. time) for simple reactions and complex metabolic and signal transduction pathways. Users can move sliders to change dissociation and kinetic constants as well as initial concentrations and see instantaneous changes in the graphs. They can also export data into a spreadsheet for further processing, such as producing derivative Lineweaver‐Burk and traditional Michaelis–Menten graphs of initial velocity (v0) versus substrate concentration. [ABSTRACT FROM AUTHOR]

External flows of energy, entropy, and matter can cause sudden transitions in the stability of biological and industrial systems, fundamentally altering their dynamical function. How might we control and design these transitions in chemical reaction networks? Here, we analyze transitions giving rise to complex behavior in random reaction networks subject to external driving forces. In the absence of driving, we characterize the uniqueness of the steady state and identify the percolation of a giant connected component in these networks as the number of reactions increases. When subject to chemical driving (influx and outflux of chemical species), the steady state can undergo bifurcations, leading to multistability or oscillatory dynamics. By quantifying the prevalence of these bifurcations, we show how chemical driving and network sparsity tend to promote the emergence of these complex dynamics and increased rates of entropy production. We show that catalysis also plays an important role in the emergence of complexity, strongly correlating with the prevalence of bifurcations. Our results suggest that coupling a minimal number of chemical signatures with external driving can lead to features present in biochemical processes and abiogenesis. [ABSTRACT FROM AUTHOR]

We study the response of chemical reaction networks driven far from equilibrium to logarithmic perturbations of reaction rates. The response of the mean number of a chemical species is observed to be quantitively limited by number fluctuations and the maximum thermodynamic driving force. We prove these trade-offs for linear chemical reaction networks and a class of nonlinear chemical reaction networks with a single chemical species. Numerical results for several model systems support the conclusion that these trade-offs continue to hold for a broad class of chemical reaction networks, though their precise form appears to sensitively depend on the deficiency of the network. [ABSTRACT FROM AUTHOR]

Enzyme catalysis in reactors for industrial applications usually require an external intervention of the species involved in the chemical reactions. We analyze the most elementary open enzyme catalysis with competitive inhibition where a time-dependent inflow of substrate and inhibitor supplies is modeled by almost periodic functions. We prove global stability of an almost periodic solution for the non-autonomous dynamical system arising from the mass-law action. This predicts a well behaved situation in which the reactor oscillates with global stability. This is a first case study in the path toward broader global stability results regarding intraspecific and monotone open reaction networks. [ABSTRACT FROM AUTHOR]

We present the first experimental application of coherent Raman spectroscopy (CRS) on the ro-vibrational ν2 mode spectrum of methane (CH4). Ultrabroadband femtosecond/picosecond (fs/ps) CRS is performed in the molecular fingerprint region from 1100 to 2000 cm−1, employing fs laser-induced filamentation as the supercontinuum generation mechanism to provide the ultrabroadband excitation pulses. We introduce a time-domain model of the CH4ν2 CRS spectrum, including all five ro-vibrational branches allowed by the selection rules Δv = 1, ΔJ = 0, ±1, ±2; the model includes collisional linewidths, computed according to a modified exponential gap scaling law and validated experimentally. The use of ultrabroadband CRS for in situ monitoring of the CH4 chemistry is demonstrated in a laboratory CH4/air diffusion flame: CRS measurements in the fingerprint region, performed across the laminar flame front, allow the simultaneous detection of molecular oxygen (O2), carbon dioxide (CO2), and molecular hydrogen (H2), along with CH4. Fundamental physicochemical processes, such as H2 production via CH4 pyrolysis, are observed through the Raman spectra of these chemical species. In addition, we demonstrate ro-vibrational CH4v2 CRS thermometry, and we validate it against CO2 CRS measurements. The present technique offers an interesting diagnostics approach to in situ measurement of CH4-rich environments, e.g., in plasma reactors for CH4 pyrolysis and H2 production. [ABSTRACT FROM AUTHOR]

Arsenic is one of the most toxic elements present in the environment, especially in water. The World Health Organization (WHO) recommends a maximum concentration of arsenic in drinkable water of 10 μg/l (10 ppb). Sensors implementing Surface Enhanced Raman Scattering (SERS) can detect chemical species at low concentrations. The aim of this study is to compare two kinds of silver-coated SERS substrates for detection and speciation of trace, trivalent and pentavalent, inorganic arsenic compounds. One type of substrate was prepared by a classical thermal evaporation technique, and the second type by an electroless process. The thermally evaporated substrates allowed the detection of As(III) only, at a limit of detection (LOD) of approximately 50 mg/l, whereas As(V) could not be detected at any analyte concentration. The electroless substrates allow one to differentiate As(III) and As(V) with a LOD 1 μg/l (1 ppb) equal for each valency, below the WHO recommendation. The electroless substrates show a very large sensitivity across up to five orders of magnitude in terms of analyte concentration. Although the SERS intensity shows a nonlinear behavior over this range of concentrations, these preliminary results are encouraging in the framework of the demonstration of trace As SERS sensors in drinkable water. [ABSTRACT FROM AUTHOR]

Hydrocarbon pyrolysis is a complex process involving large numbers of chemical species and types of chemical reactions. Its quantitative description is important for planetary sciences, in particular, for understanding the processes occurring in the interior of icy planets, such as Uranus and Neptune, where small hydrocarbons are subjected to high temperature and pressure. We propose a computationally cheap methodology based on an originally developed ten-reaction model and the configurational model from random graph theory. This methodology generates accurate predictions for molecule size distributions for a variety of initial chemical compositions and temperatures ranging from 3200 to 5000 K. Specifically, we show that the size distribution of small molecules is particularly well predicted, and the size of the largest molecule can be accurately predicted provided that this molecule is not too large. [ABSTRACT FROM AUTHOR]

The Venusian atmosphere hosts a 10 km deep convective layer that has been studied by various spacecrafts. However, the impact of the strong vertical mixing on the chemistry of this region is still unknown. This study presents the first realistic coupling between resolved small‐scale turbulence and a chemical network. The resulting vertical mixing is different for each species: those with longer chemical timescales will tend to be well‐mixed. Vertical eddy diffusion due to resolved convection motions was estimated, ranging from 102 to 104 m2/s for the 48–55 km convective layer, several orders of magnitude above the typically used value. In the 48–55 km convective layer, the impact of the small‐scale turbulence on the cloud layer boundaries was between 200 m and 1 km. The impact of turbulence on cloud chemistry is consistent with Venus Express/Visible and Infrared Thermal Imaging Spectrometer observations. The observability at the cloud‐top of small‐scale turbulence by VenSpec‐U spectrometer would be challenging. Plain Language Summary: Venus hosts a global sulfuric acid cloud layer between 45 and 70 km. A convective layer is present between roughly 50 and 60 km, with its variability in latitude and local time assessed by observation, with a thicker layer at high latitude and at night. One question that remains unclear is how this turbulence mixes momentum, heat, and chemical species. Especially, the impact of the strong vertical mixing on the chemistry of this region is still unknown. To investigate this topic, we use a convection‐resolving model coupled for the first time with a realistic chemical network. The resulting vertical mixing is different for each species: those with longer chemical timescales will tend to be well‐mixed. 1D and global circulation models use the so‐called vertical eddy diffusion approach to represent turbulent motion, quantified in our model and underestimated in chemistry models. The small‐scale turbulence in the cloud layer causes a variation in the altitude of the top and bottom boundaries of the cloud. Our model shows that the impact of turbulence on cloud chemistry corresponds well to what has been observed by satellites. In the future, the EnVision mission will be able to observe chemical species at the small turbulence scales. Key Points: Estimation for the first time of the spatial and temporal variability of chemical species due to vertical mixingQuantification of the vertical eddy diffusion coefficient, order of magnitude above typical used valuesCloud‐top altitudes change by 0.2–1 km due to vertical convective mixing and gravity waves [ABSTRACT FROM AUTHOR]

Air quality forecasting system is an essential tool widely used by environmental managers to mitigate adverse health effects of air pollutants. This work presents the latest development of the next generation regional air quality model (AQM) forecast system within the Unified Forecast System (UFS) framework in the National Oceanic and Atmospheric Administration (NOAA). The UFS air quality model incorporates the U.S. Environmental Protection Agency (EPA)'s Community Multiscale Air Quality (CMAQ) model as its main chemistry component. In this system, CMAQ is integrated as a column model to solve gas and aerosol chemistry while the transport of chemical species is processed by UFS. The current AQM version 7 (AQMv7) is coupled with an earlier version of CMAQ (version 5.2.1). Here we describe the development of the updated AQMv7 by coupling to a 'state-of-the-science' CMAQ version 5.4. The updates include improvements in gas and aerosol chemistry, dry deposition processes, and structural changes to the Input/Output (IO) interface, enhancing both computational efficiency and the representation of air-surface exchange processes. A simulation was conducted for the period of August 2023 to assess the effects of these updates on the forecast performance of ozone (O3) and fine particulate matter (PM2.5), two major air pollutants over the continental United States (CONUS). The results show that the updated model demonstrates a significantly enhanced capability in simulating O3 over the CONUS by reducing the positive bias during both day and night, leading to a reduction of the mean bias by 50 % and 72 % for hourly and the maximum daily 8-hour average O3, respectively. Spatially, the updated model lowers the positive bias of hourly O3 in all of the ten EPA regions, particularly within the Great Plains. Similarly, the updates induce uniformly lower fine particulate matter (PM2.5) concentrations across the CONUS domain, reducing the positive bias in the northeast and central Great Plain and exacerbating the negative bias in the west and south. The updated model does not improve model performance for PM2.5 in the vicinity of fire emission sources as compared to AQMv7, thus indicating a focal point of model uncertainty and needed improvement. Despite these challenges, the study highlights the importance of the ongoing refinements for reliable air quality predictions from the UFS-AQM model, which is the future replacement of NOAA's current operational air quality forecast system. [ABSTRACT FROM AUTHOR]

Production of thermoelectric materials from solution‐processed particles involves the synthesis of particles, their purification and densification into pelletized material. Chemical changes that occur during each one of these steps render them performance determining. Particularly the purification steps, bypassed in conventional solid‐state synthesis, are the cause for large discrepancies among similar solution‐processed materials. In present work, the investigation focuses on a water‐based surfactant free solution synthesis of SnSe, a highly relevant thermoelectric material. We show and rationalize that the number of leaching steps, purification solvent, annealing, and annealing atmosphere have significant influence on the Sn : Se ratio and impurity content in the powder. Such compositional changes that are undetectable by conventional characterization techniques lead to distinct consolidated materials with different types and concentration of defects. Additionally, the profound effect on their transport properties is demonstrated. We emphasize that understanding the chemistry and identifying key chemical species and their role throughout the process is paramount for optimizing material performance. Furthermore, we aim to demonstrate the necessity of comprehensive reporting of these steps as a standard practice to ensure material reproducibility. [ABSTRACT FROM AUTHOR]

Background: Volatile compounds are key elements in the interaction and communication between organisms at both interspecific and intraspecific levels. In complex bacterial communities, the emission of these fast-acting chemical messengers allows an exchange of information even at a certain distance that can cause different types of responses in the receiving organisms. The changes in secondary metabolism as a consequence of this interaction arouse great interest in the field of searching for bioactive compounds since they can be used as a tool to activate silenced metabolic pathways. Regarding the great metabolic potential that the Actinobacteria group presents in the production of compounds with attractive properties, we evaluated the reply the emitted volatile compounds can generate in other individuals of the same group. Results: We recently reported that volatile compounds released by different streptomycete species trigger the modulation of biosynthetic gene clusters in Streptomyces spp. which finally leads to the activation/repression of the production of secondary metabolites in the recipient strains. Here we present the application of this rationale in a broader bacterial community to evaluate volatiles as signaling effectors that drive the activation of biosynthesis of bioactive compounds in other members of the Actinobacteria group. Using cocultures of different actinobacteria (where only the volatile compounds reach the recipient strain) we were able to modify the bacterial secondary metabolism that drives overproduction (e.g., granaticins, actiphenol, chromomycins) and/or de novo production (e.g., collismycins, skyllamycins, cosmomycins) of compounds belonging to different chemical species that present important biological activities. Conclusions: This work shows how the secondary metabolism of different Actinobacteria species can vary significantly when exposed in co-culture to the volatile compounds of other phylum-shared bacteria, these effects being variable depending on strains and culture media. This approach can be applied to the field of new drug discovery to increase the battery of bioactive compounds produced by bacteria that can potentially be used in treatments for humans and animals. [ABSTRACT FROM AUTHOR]

We disclose an indenoannulated tridecacyclene comprising a central cyclooctatetraene moiety with multiple adjacent pentagonal rings which is accessible in a concise synthetic sequence. The saddle‐shaped geometry of the non‐benzenoid polycyclic scaffold and its unique packing behavior in the solid state were characterized by X‐ray crystallography. In electrochemical studies, the compound undergoes seven reversible redox events comprising five reductions and two oxidations. The dicationic and dianionic species obtained by chemical oxidation and reduction, respectively, were characterized spectroscopically in solution. Density functional theory calculations were applied to provide insights into aromaticity evolution in the respective charged species, highlighting the beneficial effect of the non‐benzenoid moieties on charge stabilization [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate a variety of approaches to the conversion of biomass, with a particular emphasis on employing anaerobic digestion and biogas upgrading systems. An analysis of the existing technologies is performed, with a focus on highlighting the benefits and downsides of each alternative. In order to assess the effects of nitrogen and oxygen in the biogas on the cryogenic distillation process, an investigation is being carried out. The findings suggest that the presence of these two chemical species in the biogas necessitates the final condensation of methane in order to separate them from one another. In conclusion, a qualitative economic analysis is carried out in order to ascertain the most cost-effective strategy that can be implemented in a typical Italian installation. According to the assumptions that were used, membrane separation is the solution that offers the most cost-effectiveness. [ABSTRACT FROM AUTHOR]

Biomass burning releases large amounts of aerosols and chemical species into the atmosphere, representing a major source of air pollutants. Emissions and by-products can be transported over long distances, presenting challenges in quantification. This is mainly done using satellites, which offer global coverage and data acquisition for places that are difficult to access. In this study, ground-based observations are used to assess the abundance of trace gases and aerosols. On 24 November 2020, a significant increase in formaldehyde was observed with a Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument located in Montevideo (Uruguay), and its vertical column densities reached values of 2.4×1016 molec. cm -2 , more than twice the values observed during the previous days. This was accompanied by an increase in the aerosol levels measured by an AErosol RObotic NETwork (AERONET) photometer located at the same site. The aerosol optical depth (AOD) at 440 nm reached values close to 1, an order of magnitude larger than typical values in Montevideo. Our findings indicate that the increase was associated with the passage of a plume originating from distant biomass burning. This conclusion is supported by TROPOspheric Monitoring Instrument (TROPOMI) satellite observations as well as HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) simulations. The profiles of the gases and aerosols retrieved from the MAX-DOAS observations are consistent with the HYSPLIT analysis, showing the passage of a plume over Montevideo on 24 November located at a height of ∼ 1.5 km. This corroborates the finding that biomass burning events occurring about 800 km north of Montevideo can affect the local atmosphere through long-distance emissions transport. This study underscores the potential of ground-based atmospheric monitoring as a tool for detection of such events. Furthermore, it demonstrates greater sensitivity compared to satellite when it comes to detection of relatively small amounts of carbonyls like glyoxal and formaldehyde. [ABSTRACT FROM AUTHOR]

Carbonated water flooding (CWI) increases oil production due to favorable dissolution effects and viscosity reduction. Accurate modeling of CWI performance requires a simulator with the ability to capture the true physics of such process. In this study, compositional modeling coupled with surface complexation modeling (SCM) are done, allowing a unified study of the influence in oil recovery of reduction of salt concentration in water. The compositional model consists of the conservation equations of total carbon, hydrogen, oxygen, chloride and decane. The coefficients of such equations are obtained from the equilibrium partition of chemical species that are soluble both in oleic and the aqueous phases. SCM is done by using the PHREEQC program, which determines concentration of the master species. Estimation of the wettability as a function of the Total Bound Product (TBP) that takes into account the concentration of the complexes in the aqueous, oleic phases and in the rock walls is performed. We solve analytically and numerically these equations in 1 - D in order to elucidate the effects of the injection of low salinity carbonated water into a reservoir containing oil equilibrated with high salinity carbonated water. [ABSTRACT FROM AUTHOR]

Rules that control the arrangement of chemical species within crystalline arrays of different symmetry and structural complexity are of fundamental importance in geoscience, material science, physics, and chemistry. Here, the volume of crystal phases is normalized by their ionic volume and an algebraic index that is based on their space-group and crystal site symmetries. In correlation with the number of chemical formula units Z, the normalized volumes exhibit upper and lower limits of possible structures. A bottleneck of narrowing limits occurs for Z around 80 to 100, but the field of allowed crystalline configurations widens above 100 due to a change in the slope of the lower limit. For small Z, the highest count of structures is closer to the upper limit, but at large Z, most materials assume structures close to the lower limit. In particular, for large Z, the normalized volume provides rather narrow constraints for the prediction of novel crystalline phases. In addition, an index of higher and lower complexity of crystalline phases is derived from the normalized volume and tested against key criteria. [ABSTRACT FROM AUTHOR]

Volatile oil serves as a traditional antipyretic component of Bupleuri Radix. Bupleurum marginatum var. stenophyllum (Wolff) Shan et Y. Li belongs to the genus Bupleurum and is distinguished for its high level of saikosaponins and volatile oils; nonetheless, prevailing evidence remains inconclusive regarding its viability as an alternative resource of other official species. This study aims to systematically compare the volatile oil components of both dried and fresh roots of B. marginatum var. stenophyllum and the four legally available Bupleurum species across their chemical, molecular, bionics, and anatomical structures. A total of 962 compounds were determined via GC-MS from the dried roots; B. marginatum var. stenophyllum showed the greatest differences from other species in terms of hydrocarbons, esters, and ketones, which was consistent with the results of fresh roots and the e-nose analysis. A large number of DEGs were identified from the key enzyme family of the monoterpene synthesis pathway in B. marginatum var. stenophyllum via transcriptome analysis. The microscopic observation results, using different staining methods, further showed the distinctive high proportion of phloem in B. marginatum var. stenophyllum, the structure which produces volatile oils. Together, these pieces of evidence hold substantial significance in guiding the judicious development and utilization of Bupleurum genus resources. [ABSTRACT FROM AUTHOR]