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1.
Heliyon ; 10(16): e36188, 2024 Aug 30.
Article in English | MEDLINE | ID: mdl-39253172

ABSTRACT

The Lithium-chromium phosphate Li3Cr2(PO3)4 sample was synthesized via the solid-state reaction method. The morphological integrity and chemical homogeneity were verified by energy dispersive X-ray analysis (EDX) and scanning electron microscopy (SEM). Infrared and Raman patterns were also analyzed. Optical absorption spectrum analysis, conducted within the range of 10000 cm-1 to 30000 cm-1 at room temperature, yielded some optical parameters (Eg, Eu, δ , k, n). The Neuhauser model is used to interpret the interference dip which was on the absorption spectrum of Li3Cr2(PO3)4. The Fourier transform of the autocorrelation function leads to the Zero Phonon Lines of the observed absorption energies. The electronic structure of Cr3+ (3d (Huang et al., 2009) 33) ions in Li3Cr2(PO3)4 was calculated using Racah method, which allowed for precise calculations of Racah and crystal-field parameters. The results showed good agreement between the theoretical and experimental energy levels.

2.
Front Public Health ; 12: 1367805, 2024.
Article in English | MEDLINE | ID: mdl-39247230

ABSTRACT

Background: University emergencies, garnering significant public attention and shaping network opinions, pose a crucial challenge to universities' management and societal stability. Hence, network public opinion on university emergencies is a vital issue. Nevertheless, the underlying mechanism has not been fully explored and cannot be efficiently controlled. This study aimed to explore the formation pattern of network public opinion on university emergencies, analyze its causes, and provide scientific governance strategies for coping with this issue. Methods: Based on a sample set of 204 cases from the Zhiwei Data Sharing Platform, this study classifies network public opinion on university emergencies into six types and visually analyzes their characteristics: time distribution, subject, duration, and emotion. By integrating the theory of the network public opinion field, this study develops a network public opinion field model of university emergencies to reveal its formation pattern. Furthermore, it analyzes the causes of network public opinion on university emergencies from the perspective of the public opinion lifecycle and proposes corresponding governance strategies. Results: The sample consisted of 304 cases of real-life public opinion, and the visualization results show that public opinion on mental health and teacher-student safety constitutes the predominant types, accounting for 83.3%. High-occurrence subjects are public universities (88.24%) and students (48%). The most frequent months are July and December. 90.20% of the public opinions have a lifespan of less than 19 days, with an impact index ranging from 40 to 80. The public's emotional response to different types of public opinion varies, with negative emotions dominating. Conclusion: This study provides novel insights for understanding their formation and dissemination. It also provides practical implications for relevant departments to govern network public opinion on university emergencies.


Subject(s)
Emergencies , Public Opinion , Humans , Universities , Male , Female , Adult , Students/psychology , Surveys and Questionnaires
3.
Methods Enzymol ; 703: 29-49, 2024.
Article in English | MEDLINE | ID: mdl-39261000

ABSTRACT

Non-heme iron enzymes play key roles in antibiotic, neurotransmitter, and natural product biosynthesis, DNA repair, hypoxia regulation, and disease states. These enzymes had been refractory to traditional bioinorganic spectroscopic methods. Thus, we developed variable-temperature variable-field magnetic circular dichroism (VTVH MCD) spectroscopy to experimentally define the excited and ground ligand field states of non-heme ferrous enzymes (Solomon et al., 1995). This method provides detailed geometric and electronic structure insight and thus enables a molecular level understanding of catalytic mechanisms. Application of this method across the five classes of non-heme ferrous enzymes has defined that a general mechanistic strategy is utilized where O2 activation is controlled to occur only in the presence of all cosubstrates.


Subject(s)
Catalytic Domain , Circular Dichroism , Circular Dichroism/methods , Iron/chemistry , Iron/metabolism , Nonheme Iron Proteins/chemistry , Nonheme Iron Proteins/metabolism , Oxygen/metabolism , Oxygen/chemistry , Ferrous Compounds/chemistry , Ferrous Compounds/metabolism
4.
PeerJ ; 12: e17784, 2024.
Article in English | MEDLINE | ID: mdl-39148681

ABSTRACT

Heterodonty and complex molar morphology are important characteristics of mammals acquired during the evolution of early mammals from non-mammalian synapsids. Some non-mammalian synapsids had only simple, unicuspid teeth, whereas others had complex, multicuspid teeth. In this study, we reconstructed the ancestral states of tooth morphological complexity across non-mammalian synapsids to show that morphologically complex teeth evolved independently multiple times within Therapsida and that secondary simplification of tooth morphology occurred in some non-mammalian Cynodontia. In some mammals, secondary evolution of simpler teeth from complex molars has been previously reported to correlate with an anterior shift of tooth eruption position in the jaw, as evaluated by the dentition position relative to the ends of component bones used as reference points in the upper jaw. Our phylogenetic comparative analyses showed a significant correlation between an increase in tooth complexity and a posterior shift in the dentition position relative to only one of the three specific ends of component bones that we used as reference points in the upper jaw of non-mammalian synapsids. The ends of component bones depend on the shape and relative area of each bone, which appear to vary considerably among the synapsid taxa. Quantification of the dentition position along the anteroposterior axis in the overall cranium showed suggestive evidence of a correlation between an increase in tooth complexity and a posterior shift in the dentition position among non-mammalian synapsids. This correlation supports the hypothesis that a posterior shift of tooth eruption position relative to the morphogenetic fields that determine tooth form have contributed to the evolution of morphologically complex teeth in non-mammalian synapsids, if the position in the cranium represents a certain point in the morphogenetic fields.


Subject(s)
Biological Evolution , Phylogeny , Tooth Eruption , Tooth , Animals , Tooth Eruption/physiology , Tooth/anatomy & histology , Fossils , Jaw/anatomy & histology
5.
Entropy (Basel) ; 26(8)2024 Jul 24.
Article in English | MEDLINE | ID: mdl-39202091

ABSTRACT

We develop an action principle for producing a single-fluid two-constituent system with dissipation in general relativity. The two constituents in the model are particles and entropy. The particle flux creation rate is taken to be zero, while the entropy creation rate is non-zero. Building on previous work, it is demonstrated that a new term (the proper time derivative of the matter space "metric") is required in the Lagrangian in order to produce terms typically associated with bulk and shear viscosity. Equations of motion, entropy creation rate, and energy-momentum-stress tensor are derived. Using an Onsager approach of identifying thermodynamic "forces" and "fluxes", a model is produced which delivers the same entropy creation rate as the standard, relativistic Navier-Stokes equations. This result is then contrasted with a model generated in the spirit of the action principle, which takes as its starting point a specific Lagrangian and then produces the equations of motion, entropy creation rate, and energy-momentum-stress tensor. Unlike the equations derived from Onsager reasoning, where the analogs of the bulk and shear viscosity coefficients are prescribed "externally", we find that the forms of the coefficients in the second example are a direct result of the specified Lagrangian. Furthermore, the coefficients are shown to satisfy evolution equations along the fluid worldline, also a product of the specific Lagrangian.

6.
Chemphyschem ; : e202400650, 2024 Aug 12.
Article in English | MEDLINE | ID: mdl-39133572

ABSTRACT

We present a comprehensive mean-field model that takes into account the key components of modern electrical double layer theory at the interface between an electrode and an electrolyte solution. The model considers short-range specific interactions between different species, including electrode-ion repulsion, the hydration of ions, dielectric saturation of solvent (water), and excluded volume (steric) interactions between species. By solving a modified Poisson-Boltzmann equation and using the appropriate results of quantum chemistry calculations on the hydration of ions, we can accurately approximate the differential capacitance profiles of aqueous electrolyte solutions at the boundary with a silver electrode. The specific interactions between the ions and the electrodes in the systems under consideration are assumed to be significantly weaker than their Coulomb interactions. A novel aspect of our research is the investigation of the impact of short-range ion-water interactions on the differential capacitance, which provides new insights into the behavior of the electrical double layer. This model holds the potential to be useful for electrochemical engineers working on the development of supercapacitors and related electrochemical energy storage devices. It serves as a basis for future modeling of electrolyte systems on real electrodes, especially in scenarios where chemical ion-electrode interactions are significant.

7.
J Phys Condens Matter ; 36(43)2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39029502

ABSTRACT

Motivated by the recent developments in terahertz spectroscopy using pump-probe setups to study correlated electronic materials, we review the field theoretical formalism to compute finite frequency nonlinear electro-optical responses in centrosymmetric systems starting from basic time dependent perturbation theory. We express the nonlinear current kernel as a sum of several causal response functions. These causal functions cannot be evaluated using perturbative field theory methods, since they are not contour ordered. Consequently, we associate each response function with a corresponding imaginary time ordered current correlation function, since the latter can be factorized using Wick's theorem. The mapping between the response functions and the correlation functions, suitably analytically continued to real frequencies, is proven exactly. We derive constraints satisfied by the nonlinear current kernel and we prove a generalizedf-sum rule for the nonlinear conductivity, all of which are consequences of particle number conservation. The constraints guarantee that the nonlinear static responses are free from spurious divergences. We apply the theory to compute the gauge invariant nonlinear conductivity of a system of noninteracting electrons in the presence of weak disorder. As special cases of this generalized nonlinear response, we discuss its third harmonic and its instantaneous terahertz Kerr signals. The formalism can be used to compute the nonlinear conductivity in symmetry broken phases of electronic systems such as superconductors, density waves and nematic states.

8.
J Comput Chem ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39012324

ABSTRACT

The electronic structure of the strongly correlated electron system plutonium hexaboride is studied by using single-particle approximations and a many-body approach. Imaginary components of impurity Green's functions show that 5fj=5/2 and 5fj=7/2 manifolds are in conducting and insulating regimes, respectively. Quasi-particle weights and their ratio suggest that the intermediate coupling mechanism is applicable for Pu 5f electrons, and PuB6 might be in the orbital-selective localized state. The weighted summation of occupation probabilities yields the interconfiguration fluctuation and average occupation number of 5f electrons n5f ~ 5.101. The interplay of 5f-5f correlation, spin-orbit coupling, Hund's exchange interaction, many-body transition of 5f configurations, and final state effects might be responsible for the quasiparticle multiplets in electronic spectrum functions. Prominent characters in the density of state, such as the coexistence of atomic multiplet peaks in the vicinity of the Fermi level and broad Hubbard bands in the high-lying regime, suggest that PuB6 could be identified as a Racah material. Finally, the quasiparticle band structure is also presented.

9.
Proc Natl Acad Sci U S A ; 121(29): e2323013121, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-38976737

ABSTRACT

Sr2IrO4 has attracted considerable attention due to its structural and electronic similarities to La2CuO4, the parent compound of high-Tc superconducting cuprates. It was proposed as a strong spin-orbit-coupled Jeff = 1/2 Mott insulator, but the Mott nature of its insulating ground state has not been conclusively established. Here, we use ultrafast laser pulses to realize an insulator-metal transition in Sr2IrO4 and probe the resulting dynamics using time- and angle-resolved photoemission spectroscopy. We observe a gap closure and the formation of weakly renormalized electronic bands in the gap region. Comparing these observations to the expected temperature and doping evolution of Mott gaps and Hubbard bands provides clear evidence that the insulating state does not originate from Mott correlations. We instead propose a correlated band insulator picture, where antiferromagnetic correlations play a key role in the gap opening. More broadly, our results demonstrate that energy-momentum-resolved nonequilibrium dynamics can be used to clarify the nature of equilibrium states in correlated materials.

10.
Methods Enzymol ; 701: 425-455, 2024.
Article in English | MEDLINE | ID: mdl-39025578

ABSTRACT

Adhesion of cell membranes involves multi-scale phenomena, ranging from specific molecular binding at Angstrom scale all the way up to membrane deformations and phase separation at micrometer scale. Consequently, theory and simulations of cell membrane adhesion require multi-scale modeling and suitable approximations that capture the essential physics of these phenomena. Here, we present a mesoscale model for membrane adhesion which we have employed in a series of our recent studies. This model quantifies, in particular, how nanoscale lipid clusters physically affect and respond to the intercellular receptor-ligand binding that mediates membrane adhesion. The goal of this Chapter is to present all details and subtleties of the mean-field theory and Monte Carlo simulations of this mesoscale model, which can be used to further explore physical phenomena related to cell membrane adhesion.


Subject(s)
Cell Adhesion , Cell Membrane , Monte Carlo Method , Cell Membrane/chemistry , Cell Membrane/metabolism , Computer Simulation , Models, Biological , Humans , Lipid Bilayers/chemistry , Lipid Bilayers/metabolism
11.
Entropy (Basel) ; 26(6)2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38920504

ABSTRACT

Brain-computer interfaces have seen extraordinary surges in developments in recent years, and a significant discrepancy now exists between the abundance of available data and the limited headway made in achieving a unified theoretical framework. This discrepancy becomes particularly pronounced when examining the collective neural activity at the micro and meso scale, where a coherent formalization that adequately describes neural interactions is still lacking. Here, we introduce a mathematical framework to analyze systems of natural neurons and interpret the related empirical observations in terms of lattice field theory, an established paradigm from theoretical particle physics and statistical mechanics. Our methods are tailored to interpret data from chronic neural interfaces, especially spike rasters from measurements of single neuron activity, and generalize the maximum entropy model for neural networks so that the time evolution of the system is also taken into account. This is obtained by bridging particle physics and neuroscience, paving the way for particle physics-inspired models of the neocortex.

12.
Biosystems ; 242: 105259, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38936537

ABSTRACT

In this paper we propose a control theory of manipulating holograms in Quantum Brain Dynamics (QBD) involving our subjective experiences, i.e. qualia. We begin with the Lagrangian density in QBD and extend our theory to a hierarchical model involving multiple layers covering the neocortex. We adopt reservoir computing approach or morphological computation to manipulate waveforms of holograms involving our subjective experiences. Numerical simulations performed indicate that the convergence to target waveforms of holograms is realized by external electric fields in QBD in a hierarchy. Our theory can be applied to non-invasive neuronal stimulation of the neocortex and adopted to check whether or not our brain adopts the language of holography. In case the protocol in a brain is discovered and the brain adopts the language of holography, our control theory will be applied to develop virtual reality devices by which our subjective experiences provided by the five senses in the form of qualia are manipulated non-invasively. Then, the information content of qualia might be directly transmitted into our brain without passing through sensory organs.


Subject(s)
Brain , Quantum Theory , Virtual Reality , Humans , Brain/physiology , Computer Simulation , Holography/methods , Models, Neurological , Neocortex/physiology
13.
J Am Psychoanal Assoc ; : 30651231223968, 2024 May 13.
Article in English | MEDLINE | ID: mdl-38738603

ABSTRACT

What develops in adulthood? More specifically, what develops in adult analysis, not just in terms of thwarted childhood capacities, not just through accrued experience, but even more fundamentally in terms of abilities or structures not possible until the present moment? In this paper, I posit narrative capacity-the capacity to organize conflictual aspects of self and other in a temporary causal-motivational sequence-as a core feature of what develops in the clinical encounter between the analyst and adult patient. It develops, as I demonstrate, through play with narrative fragments, contrasts, and integrations in the analytic field. I present a clinical process note to show how these elements texture and problematize one another. A successful analysis leads not to any one life story but to the more basic ability to weave and unweave our stories.

14.
Dev World Bioeth ; 2024 May 14.
Article in English | MEDLINE | ID: mdl-38742954

ABSTRACT

To ensure informed consent is tailored to ethnic Asian communities, it is necessary to establish an ethical foundation that is relevant to the specific populations. We hypothesized that certain communitarian factors unique to traditional Kyrgyz culture may influence an individual's decision to participate in research. Guided by Seedhouse's (2005) Rational Field Theory, we conducted qualitative, in-depth interviews with cultural experts in Kyrgyzstan to identify the ethical foundations of decision-making for informed consent in Kyrgyz culture. The results indicate that Kyrgyz people have a distinctive decision-making style influenced by their nomadic culture and history, which values and prioritizes family integrity and reputation. These findings indicate that a multidimensional approach based on socio-cultural sensitivities is necessary to assess the appropriateness of consent procedures. We believe our results may have implications for revising the guidelines of local and regional research ethics committees in Kyrgyzstan and other Central Asian countries.

15.
Stud Hist Philos Sci ; 105: 59-73, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38754359

ABSTRACT

This paper provides a conceptual history of the development of early universe particle physics in the 1970s, focusing on the development of more sophisticated tools for constructing gauge-theories at finite-temperature. I start with a focus on early investigations into spontaneous symmetry restoration, and continue through the development of functional methods up to equilibrium finite-temperature field theory. I argue that the early universe provides an ideal setting for integrated modelling of thermal, gravitational, and particle physics effects due to its relative simplicity. I further argue that the development of finite-temperature field theory played an important secondary role in the rise of the effective field theory worldview, and investigate the status of the analogies between phase transitions in particle physics and condensed matter physics. I find that the division into "formal" versus "physical" analogies is too coarse-grained to understand the important physical developments at play.


Subject(s)
Phase Transition , Physics , Physics/history , History, 20th Century , Temperature , Models, Theoretical
16.
Cogn Neurodyn ; 18(2): 557-579, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38699609

ABSTRACT

Because cognitive competences emerge in evolution and development from the sensory-motor domain, we seek a neural process account for higher cognition in which all representations are necessarily grounded in perception and action. The challenge is to understand how hallmarks of higher cognition, productivity, systematicity, and compositionality, may emerge from such a bottom-up approach. To address this challenge, we present key ideas from Dynamic Field Theory which postulates that neural populations are organized by recurrent connectivity to create stable localist representations. Dynamic instabilities enable the autonomous generation of sequences of mental states. The capacity to apply neural circuitry across broad sets of inputs that emulates the function call postulated in symbolic computation emerges through coordinate transforms implemented in neural gain fields. We show how binding localist neural representations through a shared index dimension enables conceptual structure, in which the interdependence among components of a representation is flexibly expressed. We demonstrate these principles in a neural dynamic architecture that represents and perceptually grounds nested relational and action phrases. Sequences of neural processing steps are generated autonomously to attentionally select the referenced objects and events in a manner that is sensitive to their interdependencies. This solves the problem of 2 and the massive binding problem in expressions such as "the small tree that is to the left of the lake which is to the left of the large tree". We extend earlier work by incorporating new types of grammatical constructions and a larger vocabulary. We discuss the DFT framework relative to other neural process accounts of higher cognition and assess the scope and challenges of such neural theories.

17.
J Phys Condens Matter ; 36(35)2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38806048

ABSTRACT

Recently, signatures of superconductivity with critical temperature from 20 to 30 K have been reported in pressured trilayer nickelate La4Ni3O10through a pressure-induced structure transition. Here we explore the evolution of electronic structures and electronic correlations in different phases of La4Ni3O10under corresponding pressure regions, by using density functional theory (DFT) combined with dynamical mean-field theory (DMFT). Similar to bilayer superconductor La3Ni2O7, the electronic bands in superconducting La4Ni3O10are dominated by Ni-3dx2-y2and 3dz2orbits near the Fermi level, in contrast, the inner Ni-O plane in La4Ni3O10generates a doublet hole-pocket Fermi surfaces around the Brillouin-zone corner, meanwhile one branch of the Ni-3dz2bands is pushed very close above the Fermi level, which can induce an electron pocket through small electron doping. The DFT+DMFT simulations suggest that the electronic correlations only give minor modification to the Fermi surfaces, meanwhile the Ni-3dz2and 3dx2-y2states on outer Ni-O layers have considerable greater mass enhancements than on the inner layer. The sensitiveness of electronic structure under doping and unique layer dependence of correlation suggest a distinct superconducting mechanism with respect to bilayer La3Ni2O7. Based on the DFT and DFT+DMFT simulations, we eventually derive a trilayer effective tight-binding model, which can produce rather precise electronic bands and Fermi surfaces, hence can serve as an appropriate model to further study the superconducting mechanism and paring symmetry in trilayer La4Ni3O10.

18.
Front Robot AI ; 11: 1362735, 2024.
Article in English | MEDLINE | ID: mdl-38694882

ABSTRACT

We introduce a novel approach to training data augmentation in brain-computer interfaces (BCIs) using neural field theory (NFT) applied to EEG data from motor imagery tasks. BCIs often suffer from limited accuracy due to a limited amount of training data. To address this, we leveraged a corticothalamic NFT model to generate artificial EEG time series as supplemental training data. We employed the BCI competition IV '2a' dataset to evaluate this augmentation technique. For each individual, we fitted the model to common spatial patterns of each motor imagery class, jittered the fitted parameters, and generated time series for data augmentation. Our method led to significant accuracy improvements of over 2% in classifying the "total power" feature, but not in the case of the "Higuchi fractal dimension" feature. This suggests that the fit NFT model may more favorably represent one feature than the other. These findings pave the way for further exploration of NFT-based data augmentation, highlighting the benefits of biophysically accurate artificial data.

19.
Psychoanal Q ; 93(1): 105-134, 2024.
Article in English | MEDLINE | ID: mdl-38578262

ABSTRACT

This paper explores the intricate nexus of writing and psychoanalysis by addressing a key question: In what and how many directions should analytic writing be ethical? The author structures the argument across three axes. First, in an introduction, writing's role as a psychoanalytic invariant is emphasized. Then, an exploration ensues, delving into writing as praxis, navigating complex technical choices, from micro- to macro-perspectives in clinical vignettes, their autobiographical essence, their relevance as models for theory, self-revelation, etc. Lastly, a succinct epilogue considers the relationship between aesthetics and ethics in psychoanalytic writing.


Subject(s)
Psychoanalysis , Psychoanalytic Therapy , Humans , Writing , Psychoanalytic Theory
20.
Int J Mol Sci ; 25(7)2024 Mar 29.
Article in English | MEDLINE | ID: mdl-38612655

ABSTRACT

In this paper we would like to highlight the problems of conceiving the "Hydrogen Bond" (HB) as a real short-range, directional, electrostatic, attractive interaction and to reframe its nature through the non-approximated view of condensed matter offered by a Quantum Electro-Dynamic (QED) perspective. We focus our attention on water, as the paramount case to show the effectiveness of this 40-year-old theoretical background, which represents water as a two-fluid system (where one of the two phases is coherent). The HB turns out to be the result of the electromagnetic field gradient in the coherent phase of water, whose vacuum level is lower than in the non-coherent (gas-like) fraction. In this way, the HB can be properly considered, i.e., no longer as a "dipolar force" between molecules, but as the phenomenological effect of their collective thermodynamic tendency to occupy a lower ground state, compatible with temperature and pressure. This perspective allows to explain many "anomalous" behaviours of water and to understand why the calculated energy associated with the HB should change when considering two molecules (water-dimer), or the liquid state, or the different types of ice. The appearance of a condensed, liquid, phase at room temperature is indeed the consequence of the boson condensation as described in the context of spontaneous symmetry breaking (SSB). For a more realistic and authentic description of water, condensed matter and living systems, the transition from a still semi-classical Quantum Mechanical (QM) view in the first quantization to a Quantum Field Theory (QFT) view embedded in the second quantization is advocated.


Subject(s)
Electromagnetic Fields , Polymers , Hydrogen Bonding , Water , Hydrogen
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