Chemical Potential Research Articles

The chemical composition, antioxidative and antimicrobial potentials of Toona sinensis essential oils from different regions of China

Toona sinensis is one of the traditional Chinese medicinal materials with rich physiological activities. This study aimed to investigate the chemical composition differences of the essential oils from the tender leaves and shoots of T. sinensis, collected from four main producing areas in China, and to verify their anti-listeria and antioxidant properties. Gas chromatography-mass spectrometry (GC-MS) analysis was conducted on the essential oils obtained by hydro-distillation. The results indicated that compounds such as β-elemene (3.5∼8.1%), α-caryophyllene (3.7∼7.2%), and trans-caryophyllene (4.0∼9.7%) were the main common components of T. sinensis essential oils (TSEO) from four producing areas. The results of DPPH and ABTS showed that the essential oil from Dazhou, Sichuan, China had the best antioxidant effect. At a concentration of 1.25 mg/mL, the antioxidant activity of TSEO-DZ from Sichuan was comparable to 0.08 mg/mL of BHT and was only slightly lower than 0.06 mg/mL of VC. The broth dilution method showed that the essential oil from Tai ‘an, Shandong, China, showed better antibacterial effect, with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MLC) values of 1.25 μL/mL and 2.54 μL/mL, respectively. This study demonstrates that TSEO possesses promising application potential in antioxidant and anti-listeria activities, and it confirms that the growth environment of T. sinensis significantly influences the quality, content, and biological activity of the essential oil.

Information theoretic measures on quantum droplets in ultracold atomic systems

We consider Shannon entropy, Fisher information, Rényi entropy, and Tsallis entropy to study the quantum droplet phase in Bose–Einstein condensates. In the beyond mean-field description, the Gross–Pitaevskii equation with Lee-Huang-Yang correction gives a family of quantum droplets with different chemical potentials. At a larger value of chemical potential, quantum droplet with sharp-top probability density distribution starts to form while it becomes flat top for a smaller value of chemical potential. We show that entropic measures can distinguish the shape change of the probability density distributions and thus can identify the onset of the droplet phase. During the onset of droplet phase, the Shannon entropy decreases gradually with the decrease of chemical potential and attains a minimum in the vicinity where a smooth transition from flat-top to sharp-top QDs occurs. At this stage, the Shannon entropy increases abruptly with the lowering of chemical potential. We observe an opposite trend in the case of Fisher information. These results are found to be consistent with the Rényi and Tsallis entropic measures.

DiDBiT-TMT: A Novel Method to Quantify Changes in the Proteomic Landscape Induced by Neural Plasticity.

Direct detection of biotinylated proteins (DiDBiT) is a proteomic method that can enrich and detect newly synthesized proteins (NSPs) labeled with bio-orthogonal amino acids with 20-fold improved detectability compared to conventional methods. However, DiDBiT has currently been used to compare only two conditions per experiment. Here, we present DiDBiT-TMT, a method that can be used to quantify NSPs across many conditions and replicates in the same experiment by combining isobaric tandem mass tagging (TMT) with DiDBiT. We applied DiDBiT-TMT to brain slices to determine changes in the de novo proteome that occur after inducing chemical long-term potentiation (cLTP) or treatment with the neuromodulator norepinephrine. We successfully demonstrated DiDBiT-TMT's capacity to quantitatively compare up to 9 samples in parallel. We showed that there is a minimal overlap among NSPs that are differentially expressed in cLTP-treated organotypic brain slices, norepinephrine-treated organotypic brain slices, and organotypic slices undergoing combinatorial treatment with norepinephrine and cLTP. Our results point to the possible divergence of the molecular mechanisms underlying these treatments and showcase the applicability of DiDBiT-TMT for studying neurobiology.

On the Functionalization of C60 with Vinylallenes Generated in situ by Rhodium Catalysis

The functionalization of fullerenes is important for several reasons, primarily related to enhancing their chemical reactivity, solubility, and potential of applications in optoelectronics and biomedicine. In this study, we present a novel approach to functionalize C60 through a cascade process encompassing an unprecedented Rh‐catalyzed cycloisomerization of 1,6‐allenynes to in situ generate a vinylallene that is followed by a Diels‐Alder reaction with pristine fullerene, resulting in the formation of 6,6‐fused bicyclic fullerene derivatives. The mechanism governing this process was elucidated by DFT calculations and confirmed by deuterium labelling and control experiments, demonstrating the critical role of traces of water in the reaction medium to mediate the observed reactivity.

Comparative genomics unravels a rich set of biosynthetic gene clusters with distinct evolutionary trajectories across fungal species (Termitomyces) farmed by termites

The use of compounds produced by hosts or symbionts for defence against antagonists has been identified in many organisms, including in fungus-farming termites (Macrotermitinae). The obligate mutualistic fungus Termitomyces plays a pivotal role in plant biomass decomposition and as the primary food source for these termites. Despite the isolation of various specialized metabolites from different Termitomyces species, our grasp of their natural product repertoire remains incomplete. To address this knowledge gap, we conducted a comprehensive analysis of 39 Termitomyces genomes, representing 21 species associated with members of five termite host genera. We identified 754 biosynthetic gene clusters (BGCs) coding for specialized metabolites and categorized 660 BGCs into 61 biosynthetic gene cluster families (GCFs) spanning five compound classes. Seven GCFs were shared by all 21 Termitomyces species and 21 GCFs were present in all genomes of subsets of species. Evolutionary constraint analyses on the 25 most abundant GCFs revealed distinctive evolutionary histories, signifying that millions of years of termite-fungus symbiosis have influenced diverse biosynthetic pathways. This study unveils a wealth of non-random and largely undiscovered chemical potential within Termitomyces and contributes to our understanding of the intricate evolutionary trajectories of biosynthetic gene clusters in the context of long-standing symbiosis.

Signature of pressure-induced topological phase transition in ZrTe5

The layered van der Waals material ZrTe5 is known as a candidate topological insulator (TI), however its topological phase and the relation with other properties such as an apparent Dirac semimetallic state is still a subject of debate. We employ a semiclassical multicarrier transport (MCT) model to analyze the magnetotransport of ZrTe5 nanodevices at hydrostatic pressures up to 2 GPa. The temperature dependence of the MCT results between 10 and 300 K is assessed in the context of thermal activation, and we obtain the positions of conduction and valence band edges in the vicinity of the chemical potential. We find evidence of the closing and re-opening of the band gap with increasing pressure, which is consistent with a phase transition from weak to strong TI. This matches expectations from ab initio band structure calculations, as well as previous observations that CVT-grown ZrTe5 is a weak TI in ambient conditions.

Finite temperature fermionic condensate and energy–momentum tensor in cosmic string spacetime

Here we analyze the expectation value of the fermionic condensate and the energy–momentum tensor associated with a massive charged fermionic quantum field with a nonzero chemical potential propagating in a magnetic-flux-carrying cosmic string in thermal equilibrium at finite temperature T. The expectation values of the fermionic condensate and the energy–momentum tensor are expressed as the sum of vacuum expectation values and the finite temperature contributions coming from the particles and antiparticles excitation. The thermal expectations values of the fermionic condensate and the energy–momentum tensor are even periodic functions of the magnetic flux with period being the quantum flux, and also even functions of the chemical potential. Because the analyses of vacuum expectation of the fermionic condensate and energy–momentum tensor have been developed in literature, here we are mainly interested in the investigation of the thermal corrections. In this way we explicitly study how these observable behaves in the limits of low and high temperatures, and also for points near the string. Besides the analytical discussions, we included some graphs that exhibit the behavior of these observable for different values of the physical parameters of the model.

Real-time chiral dynamics at finite temperature from quantum simulation

In this study, we explore the real-time dynamics of the chiral magnetic effect (CME) at a finite temperature in the (1+1)-dimensional QED, the massive Schwinger model. By introducing a chiral chemical potential μ5 through a quench process, we drive the system out of equilibrium and analyze the induced vector currents and their evolution over time. The Hamiltonian is modified to include the time-dependent chiral chemical potential, thus allowing the investigation of the CME within a quantum computing framework. We employ the quantum imaginary time evolution (QITE) algorithm to study the thermal states, and utilize the Suzuki-Trotter decomposition for the real-time evolution. This study provides insights into the quantum simulation capabilities for modeling the CME and offers a pathway for studying chiral dynamics in low-dimensional quantum field theories.

Information theoretic measures for Lifshitz system

In this work, we have studied various mixed state information theoretic quantities for an excited state of Lifshitz spacetime in 3 + 1-dimensions. This geometry is the gravity dual to a class of 2 + 1-dimensional quantum field theories having Lifshitz symmetry. We have holographically calculated mutual information, entanglement wedge cross section, entanglement negativity and mutual complexity for strip like subsystems at the boundary. For this we have used the results of holographic entanglement entropy and complexity present in the literature. We first calculate all of these mentioned quantities for the pure state of Lifshitz spacetime. Then we have moved on to calculate all these quantities for excited state of the Lifshitz spacetime. The gravity dual of excited state of Lifshitz systems in field theory can be obtained by applying constant perturbations along the boundary direction. Further, we would like to mention that for the simplicity of calculation we are only considering results up to the first order in perturbation. The change in the obtained holographic information theoretic quantities are then related to entanglement entropy, entanglement pressure, entanglement chemical potential and charge using the stress tensor complex. These relations are analogous to the first law of entanglement thermodynamics given earlier in the literature. All the calculations are carried out for both values of dynamical scaling exponent (z) present in the Lifshitz field theory.

Development of new sustainable pyridinium ionic liquids: From reactivity studies to mechanism-based activity predictions.

This study addresses the development of sustainable pyridinium ionic liquids (ILs) because of their potential applications in agriculture and pharmaceuticals. Pyridinium-based ILs are known for their low melting points, high thermal stability, and moderate solvation properties. We synthesized three novel pyridinium-based ILs: 1-(2-(isopentyloxy)-2-oxoethyl)pyridin-1-ium chloride, 1-(2-(hexyloxy)-2-oxoethyl)pyridin-1-ium chloride, and 1-(2-(benzyloxy)-2-oxoethyl)pyridin-1-ium chloride. The biological activities of these compounds were evaluated through plant growth promotion, herbicidal, and insecticidal assays. Our results show that the benzyloxy derivative significantly enhances wheat and cucumber growth, whereas the isopentyloxy compound has potent herbicidal effects. Computational methods, including DFT calculations and molecular docking, were applied to understand the structure‒activity relationships (SARs) and mechanisms of action. The computational techniques involved dispersion-corrected density functional theory (DFT) with the B3LYP functional and the 6-311G** basis set. Grimme's D3 corrections were included to account for dispersion interactions. The calculations were performed via GAMESS-US software. Quantum descriptors of reactivity, such as ionization potential, electron affinity, chemical potential, and electrophilicity index, were derived from the HOMO and LUMO energies. Molecular docking studies were conducted via the CB-Dock server via AutoDock Vina software to predict binding affinities to cancer-related proteins. Petra/Osiris/Molinspiration (POM) analysis was used to predict the drug likeness and other pharmaceutical properties of the synthesized ILs.

Machine Learning-Based Toxicological Modeling for Screening Environmental Obesogens.

The emerging presence of environmental obesogens, chemicals that disrupt energy balance and contribute to adipogenesis and obesity, has become a major public health challenge. Molecular initiating events (MIEs) describe biological outcomes resulting from chemical interactions with biomolecules. Machine learning models based on MIEs can predict complex toxic end points due to chemical exposure and improve the interpretability of models. In this study, a system was constructed that integrated six MIEs associated with adipogenesis and obesity. This system showed high accuracy in external validation, with an area under the receiver operating characteristic curve of 0.78. Molecular hydrophobicity (SlogP_VSA) and direct electrostatic interactions (PEOE_VSA) were identified as the two most critical molecular descriptors representing the obesogenic potential of chemicals. This system was further used to predict the obesogenic effects of chemicals on the candidate list of substances of very high concern (SVHCs). Results from 3T3-L1 adipogenesis assays verified that the system correctly predicted obesogenic or nonobesogenic effects of 10 of the 12 SVHCs tested, and identified four novel potential obesogens, including 2-benzotriazol-2-yl-4,6-ditert-butylphenol (UV-320), 4-(1,1,5-trimethylhexyl)phenol (p262-NP), 2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethanol (OP1EO) and endosulfan. These validation data suggest that the screening system has good performance in adipogenic prediction.

High-temperature transport properties of a two-dimensional weakly doped parabolic semiconductor.

A version of the Mexican-hat Hamiltonian is used to study high-temperature transport properties of a two-dimensional weakly doped semiconductor with electron-hole symmetric bands. For a finite doping level and a temperature-dependent band gap, we find a closed analytical form of the temperature-dependent chemical potential. The effective concentrations of charge carriers participating in transport coefficients are analyzed in the space spanned by the total electron concentration and temperature. It is shown that these concentrations are the sum of a residual contribution and two thermally activated contributions, with a complicated dependence on temperature. The analytical expression for the Hall coefficient RHis also found. It is argued that it is a non-monotonic function of the doping level with the maximum at the doping nmax that is a linear function of temperature at high enough temperatures. The analysis of the real part of the interband conductivity shows that it is inversely proportional to incoming photon energy at low temperatures and that it is nearly constant over a wide energy range at high temperatures. This results are expected to be of significant importance in understanding transport and optical properties of weakly doped two-dimensional semiconductors with nearly symmetric parabolic bands.&#xD.

Comparing phase sensitive detection and Fourier analysis of modulation excitation spectroscopy data exemplified by Ambient Pressure X-ray Photoelectron Spectroscopy

Dynamic processes in catalysis are gaining increased attention and could very well be one of the next frontiers in surface science. One way to study such processes is to induce chemical changes on the surface for example by periodically adjusting the (electro)chemical potential in situ and identify the resulting spectral changes. Often this is referred to as Modulation Excitation Spectroscopy (MES). Using Ambient Pressure Photoelectron Spectroscopy data, we here discuss and compare the analysis of MES data using both Phase Sensitive Detection (PSD) and Fourier analysis. We discuss that PSD determines the component magnitude at a user-defined phase value while Fourier analysis provides the maximum oscillation amplitude and respective phase value of oscillating spectral features. We discuss advantages and disadvantages of the different analysis schemes and explore how the full time-evolution can be obtained.

Towards a high-rate operation of contact stabilization process: a microscopic view of carbon capture properties

Carbon capture performance is a key factor determining the chemical energy recovery potential of the high-rate contact stabilization (HiCS) process. However, the mechanisms of organic carbon capture are complex, involving surface adsorption, extracellular adsorption, and intracellular storage. A unique characteristic of the HiCS process is its low sludge residence time (SRT). Unfortunately, the influence of SRT on carbon capture has not been thoroughly studied, especially in terms of the underlying mechanisms. In this study, the microscopic changes in carbon capture performance during the transition from a conventional contact stabilized (CS) system to a high-rate mode of operation were demonstrated using intracellular carbon sources, extracellular polymeric substances (EPS), signaling molecules, and microbial community assays. The results showed that the extracellular carbon adsorption and intracellular carbon storage performance increased, and the microbial community structure changed significantly with converting the CS system to the high-rate operation mode. The enhancement of extracellular carbon adsorption performance mainly relied on the growth of EPS, which was accomplished by the strong growth of the relative abundance of the dominant bacterial group Cloacibacterium within the HiCS system, offsetting the negative effect produced by the decline of acyl-homoserine lactones. 98 mgCOD/gSS, 343 mgCOD/gSS, and 500 mgCOD/gSS of PHAs per sludge unit were obtained at SRT-24d, 8d, and 2d, respectively, suggesting that the HiCS system is more advantageous for rapid PHAs production.

Strangeness-correlations on the pseudocritical line in ( 2+1 )-flavor QCD

We present some lattice QCD results on first (χ1i) and second (χ2i) cumulants of and correlations (χ11ij) among net baryon-number (B), strangeness (S) and electric charge (Q) along the pseudocritical line [Tpc(μB)] in the temperature (T)–baryon chemical potential (μB) phase diagram of (2+1)-flavor QCD. We point out that violations of sum rules among second order cumulants, which hold in the isospin symmetric limit of vanishing electric charge chemical potential, are small along the Tpc(μB) for the entire range of μB covered in the RHIC beam energy scan. For the strangeness neutral matter produced in heavy-ion collisions this leads to a close relation between χ11BS and χ11QS. We compare lattice QCD results for χ11BS/χ2S along the Tpc(μB) line with preliminary experimental measurements of χ11BS/χ2S for collision energies 7.7 GeV≤sNN≤62.4 GeV. While we find good agreements for sNN≥39 GeV, differences are sizeable at smaller values of sNN. Moreover, we compare lattice QCD results for the ratio of the strangeness (μS) to baryon (μB) chemical potentials, which define a strangeness neutral system with fixed electric charge to baryon number density, with experimental results obtained by the STAR collaboration for μS/μB using strange baryon yields on the freeze-out line. Finally, we determine the baryon chemical potential at the freeze-out (μBf) by comparing χ1B/χ2B along the Tpc(μB) with the experimentally measured net-proton cumulants χ1p/χ2p. We find that {μBf,Tpc(μBf)} are consistent with the freeze-out parameters of the statistical-model fits to experimentally measured hadron yields for sNN≥11.5 GeV. Published by the American Physical Society 2024

Charged AdS black holes with higher derivative corrections in the presence of string cloud

We have obtained charged asymptotically anti-de Sitter (AdS) black hole solutions in Einstein–Gauss–Bonnet gravity in the presence of string cloud. It turns out that there exist three black holes in certain range of parameters for small enough chemical potential. However, for large chemical potential, these black holes merge into a single one. The free energy of the black holes is computed from the on-shell Euclidean action by subtracting the contribution of an extremal black hole. We have studied the free energy and specific heat of the solutions, which shows that the medium-sized black hole is unstable. As an application, we have studied the quark–antiquark potential in the dual gauge theory. This study provides necessary ingredients for the study of the dual theories in the context of condensed matter systems.

A comprehensive review on chemical and pharmacological potential of Synsepalum dulcificum (Schumach. & Thonn.) Daniell

The fruit of plant Synsepalum dulcificum(Schumach. & Thonn.) Daniell, is found native to tropical regions of West Africa, and vernacularly recognized as the “Miracle Fruit” by Africans. The property of the plant has traditionally been employed in many food industries, besides its ethnopharmacological significance. The phytochemical analysis from literature reveals that various parts of plant contains many bioactive components including alkaloids, lignans, phenolic acids, glycoproteins and flavonoids. Recent studies exhibit its pharmacologicalpotential such as antidiabetic, antihyperlipidemic, anti-cancer, antimicrobial, antioxidant, anti-hyperuricemia and anti-convulsant properties. Therefore, this review aims to systematically summarizes scientific evidences with the therapeutic, ethnopharmacological and traditional claims found in literature. However, the data acquired is still very imperfect, thus future research is hopeful to discover the precise mechanism of action of its bioactive components to explore chemical constituents, and their nutraceutical and clinical uses of this multipurpose plant to employ its valuable effects on human beings.

Phytochemical investigation and spectral characterization of isolated compounds from Pyracantha crenulata (D. Don) M. Roem (syn. Crataegus crenulata Roxb) leaves: evaluation of antioxidant activity and molecular docking analysis

Pyracantha crenulata (D. Don) M. Roem (syn. Crataegus crenulata Roxb.) is an evergreen shrub in the Rosaceae family, notable for its chemical diversity and biological potential. This study isolates and characterises six compounds (Cc-1 to Cc-6), including four new ones, using repeated column chromatography. Structural elucidation employed IR, UV-vis, 1H and 13 C NMR, and mass spectrometry. The DPPH assay was used to test the antioxidant activity in vitro. Compounds Cc-4, Cc-2, Cc-1, and Cc-5 had IC50 values of 15.734 μg/ml, 51.422 μg/ml, 62.864 μg/ml, and 71.622 μg/ml, in that order. Quantitative phytochemical analysis revealed flavonoid content (22.81 mg/g), tannin content (385.15 mg/g), and total phenolic content (128.78 mg/g). Human cyclin-dependent kinase 2 (CDK2) (PDB ID: 1hck) docked with compound Cc-4, which demonstrated strong antioxidant activity and revealed significant non-bonding interactions. The pkCSM and SwissADME analyses suggested promising drug-like properties for Cc-4, supported by BOILED-Egg diagrams highlighting its therapeutic potential.

Constrained Hamiltonian dynamics for electrons in magnetic field and additional forces besides the Lorentz force acting on electrons

Abstract We consider the forces acting on electrons in magnetic field including the constraints and a condition arising from quantum mechanics. The force is calculated as the electron mass, me, multiplied
by the total time-derivative of the velocity field evaluated using the quantum mechanical many-electron wave function. The velocity field includes a term of the Berry connection from the many-body wave function; thereby, quantum mechanical effects are included.
It is shown that additional important forces besides the Lorentz force exist; they include the gradient of
the electron velocity field kinetic energy, the gradient of the chemical potential, and the `force' for producing topologically protected loop currents.
These additional forces are shown to be important in superconductivity,
electric current in metallic wires, and charging of capacitors.

CSEL-BGC: A Bioinformatics Framework Integrating Machine Learning for Defining the Biosynthetic Evolutionary Landscape of Uncharacterized Antibacterial Natural Products.

The sluggish pace of new antibacterial drug development reflects a vulnerability in the face of the current severe threat posed by bacterial resistance. Microbial natural products (NPs), as a reservoir of immense chemical potential, have emerged as the most promising avenue for the discovery of next generation antibacterial agent. Directly accessing the antibacterial activity of potential products derived from biosynthetic gene clusters (BGCs) would significantly expedite the process. To tackle this issue, we propose a CSEL-BGC framework that integrates machine learning (ML) techniques. This framework involves the development of a novel cascade-stacking ensemble learning (CSEL) model and the establishment of a groundbreaking model evaluation system. Based on this framework, we predict 6,666 BGCs with antibacterial activity from 3,468 complete bacterial genomes and elucidate a biosynthetic evolutionary landscape to reveal their antibacterial potential. This provides crucial insights for interpretating the synthesis and secretion mechanisms of unknown NPs.