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At least 19 recordsLinked to original sources
PubMed1979

[Quantum analysis of postsynaptic potentials].

Basic formulations of the quantum theory for synaptic transmission are listed. Methods for determining the mean quantum content, quantum value and binomial parameters describing the amplitude distributions of the unitary and "minimal" postsynaptic potentials are discussed. Literature and author's determinations of the quantum parameters for the synapses of the central nervous system are described. The comparison is made with similar determinations for more studied peripheral junctions. Some difficulties and perspective of the quantum theory are discussed.

Animals↗
PubMed1979

Computing in the bio-sciences with hypernumbers: a survey.

A survey of higher types of number, with more sophisticated arithmetics than square root -1, is presented. Such powerful embodiments of the number concept are capable of representing entities and operations in the bio-sciences, where phenomena are characteristically more recondite than in naively reductionist, mechanistic physics or chemistry, which today even quantum theory (which itself deploys two kinds of hypernumber) has shown to be inadequate to explain observed phenomena. When the bio-sciences enter the picture, four other kinds of hypernumber are needed, one of them (w) relating also to the frontiers of quantum theory, in terms of the resolution of problems such as the breakdown of parity conservation and of time reversal, and the concomitant elimination of unwanted divergences (infinities). A brief statement of the relevance of each of the additional kinds of hypernumbers in bio-scientific computing is furnished, as an introduction to an approach that is not only viable in terms of digital computing, but is fraught with new implications for bio-scientific research.

Computers↗
PubMed1976

On the Comorosan effect.

A possible explanation for the necessary and sufficient irradiation to produce the controversial Comorosan effect is discussed. Using a modified quantum theory requiring a definition of the relation of four parameters of a light signal instead of the usual two, the lack of superposition of irradiating sources is accounted for as well as the ineffectiveness of all parts of the total visible spectrum. The most effective average wavelength for obtaining the effect is unique merely because of the appropriateness of the bandwidth of the filter. Changing the filter bandwidth in a way related to a change in the average wavelength should produce the effect at other average wavelengths. The storage of energy within the irradiated substance is considered to be due to either a resonance effect with photon annihilation or a Raman effect with photon scattering.

Enzymes↗
PubMed2025

Enzymatic Anti-Baldwin Ring-Closure Cascade for Fused Bicyclic Ether Formation.

Pyrenulic acids are cytotoxic polyketides isolated from the ascomycete Pyrenula sp. derived from Vietnamese lichen that are characterized by complex fused cyclic core structures. Genome sequencing, in silico sequence analysis, and RT-PCR studies identified the pyrenulic acid (pya) biosynthetic gene cluster. Based on a functional analysis of the enzymes by expression of each gene in a heterologous host using Aspergillus nidulans, we discovered two cytochrome P450s PyaJ and PyaG that effect epoxidation and hydroxylation of the alkyl chain terminal, respectively, and an α/β hydrolase PyaF that constructs a 6- and 7-membered fused bicyclic diether skeleton by catalyzing successive epoxide ring-opening 6-endo and 7-endo cyclization reactions. To elucidate the detailed mechanism of pyrenulic acid formation, we obtained PyaF as a recombinant enzyme and performed an in vitro experiment, which confirmed catalysis by PyaF of the cyclization reaction. In addition, we performed alignment analysis of PyaF with α/β hydrolases with known functions, as well as an in-depth computational study. In-depth computational analyses of the cyclization reaction pathways with density functional theory quantum mechanics and detailed characterization of PyaF by Chai-1-based protein structure modeling with molecular dynamics simulations and site-specific mutagenesis predicted the active amino acid residues of this serine α/β hydrolase to be an unusual catalytic serine tetrad involving Ser170, Asn342, Asp314, and His169, with Tyr255 and His284 acting as general bases to facilitate opening of the epoxides. Our study provides insight into how regioselectivity of enzymatic anti-Baldwin epoxide ring-opening cascades for the formation of a fused cyclic ether structure is controlled.

Cyclization↗
PubMed1978

A new theory of cochlear function based on quasi quantum considerations.

A new theory of cochlear function is proposed. It locates the 2nd filter in the IHC which are regarded as biological resonators. The OHC play no part in frequency discrimination. Confirmation of the theory is derived from the fact that it offers plausible explanations for many otherwise unexplained paradoxes in the distribution of cochlear microphonics. It also explains why combination tones only occur in very restricted frequency regions, and it predicts their relative audibility. Finally a test is proposed whereby the theory must stand or fall.

Cochlea↗
PubMedDate not supplied

[Electronic-conformational interactions of molecular-biological systems. I. Quantum-chemical aspect of the theory of electronic-conformational interaction].

Electronic-conformational interactions (ECI) are the main causes of enzymatic catalysis and other biological processes, occuring at the molecular and super-molecular levels. For the studies of several problems, related to ECI the qualitative methods of quantum chemistry can be used, in particular the method of intermolecular orbitals. The possibilities of this method are shown in some simple cases.

Biopolymers↗
PubMed1976

Theory of spatial-frequency filtering by the human visual system. I. Performance limited by quantum noise.

A theory and model of the visual system are presented to explain the detection of static sinusoidal gratings near the threshold. The model incorporates a set of independent decision centers and associated photoreceptive fields (PRFs). The decision criterion value at each decision center is proportional to the standard deviation of the excitation current transmitted from a PRF to its associated decision center caused by quantum fluctuations in the absorption of light. It is well known that the spatial-frequency-response (SFR) function and the spatial-impulse-response (SIR) function of a photodetector are a Fourier transform pair. A systematic examination of the SIR and SFR functions of PRF configurations consisting of rectangular regions of alternately excitatory and inhibitory response reveals that modulation sensitivity of the visual system is explained at scotopic and photopic illuminance by a set of PRFs composed of a single excitatory region and a central excitatory region bordered by inhibitory regions, respectively. The complete model is shown to yield a high degree of conformity between theoretical and experimental threshold modulation curves.

Decision Making↗
PubMed2026

Applications of quantum AI in brain disorder diagnosis: A systematic review.

BACKGROUND AND OBJECTIVE: Brain disorder diagnosis and prediction remain challenging because neuroimaging, electrophysiological, behavioral, and multimodal data are high-dimensional, noisy, heterogeneous, and limited by small clinical cohorts. This systematic review synthesised applications of quantum artificial intelligence (QAI) for brain disorder diagnosis, prediction, detection, and monitoring. METHODS: Following PRISMA guidelines, studies published from 2016 to 13 January 2026 were retrieved from Scopus, Web of Science, and IEEE Xplore. After screening, 36 studies met the eligibility criteria and were qualitatively analysed according to disorder category, data modality, QAI method, implementation setting, validation strategy, and performance. RESULTS: At the broader disease-group level, neurodegenerative disorders were the most frequently investigated, followed by mental health and psychiatric disorders. At the individual level, Parkinson's disease and schizophrenia were the leading applications, followed by depression, anxiety, Alzheimer's disease, and stress-related tasks. MRI-based modalities were the most frequently used data source, followed by multimodal data and EEG. Methodologically, primary QAI approaches were dominated by quantum neural and QDL architectures, followed by quantum-inspired optimization or feature-selection methods and quantum-kernel/conventional QML classifiers. Qiskit/IBM Quantum and PennyLane were the most frequently reported quantum software frameworks. However, most studies relied on simulators, classical quantum-inspired implementations, or unclear implementation settings, with limited real-hardware evaluation. CONCLUSIONS: QAI shows emerging potential for brain disorder analysis, particularly through hybrid quantum-classical learning, quantum neural architectures, quantum-kernel methods, and quantum-inspired optimization. Nevertheless, current evidence remains preliminary and requires larger datasets, subject-level and external validation, fair classical benchmarking, noise-resilient circuits, real quantum hardware evaluation, explainability, and clinical validation.

Humans↗
PubMed2025

Generating three-dimensional genome structures with a variational quantum algorithm.

Chromosome conformation capture experiments have revealed the underlying spatial interactions that govern three-dimensional (3D) genome organization and topology. Detecting 3D contacts between genomic loci considerably enhances our understanding of fundamental regulatory processes. Modeling 3D structures from experimental contact matrices can further contextualize the relationship between 3D genome organization and regulation. While classical algorithms have been successful in reconstructing genomic conformations, we investigate the prospect of quantum computation to aid in modeling the conformational space. In this context, we propose a novel variational quantum algorithm (VQA) to model the distribution of 3D genomic structures from experimental contact data. Through rigorous evaluations, we demonstrate the capability of our algorithm to sample ensembles of viable 3D conformations that agree well with experimental and simulated contact data. Furthermore, we extend our methodology to model the conformational space of a single cell or a population of cells. In the advent of sufficient quantum utility, the insights gained from this study can serve as a foundation for investigating high-resolution, large-scale ensembles of genomic conformations through generative VQAs.

Algorithms↗
PubMed2026

Quantum computing-assisted validation of a conserved macrophage suppression module shared by ASFV and PEDV.

BACKGROUND: African swine fever virus (ASFV) and porcine epidemic diarrhea virus (PEDV) differ in viral biology and cellular tropism, yet both pathogens suppress macrophage-mediated immune responses in pigs. OBJECTIVE: To identify a conserved macrophage suppression module shared by ASFV and PEDV and evaluate quantum computing as an independent framework for biological network validation. METHODS: Integrated analysis of publicly available GEO datasets (GSE231435 for ASFV and GSE306895) identified 471 shared downregulated genes. A network- and multi-omics-informed 20-gene core was selected and encoded as a 20-qubit modularity-based Quadratic Unconstrained Binary Optimization (QUBO) problem. Community detection was benchmarked using the Quantum Approximate Optimization Algorithm (QAOA) on both the IBM Quantum Aer simulator and the 156-qubit IBM Fez (Heron r2) quantum processor and compared with brute-force enumeration and simulated annealing. RESULTS: A conserved macrophage suppression module shared by ASFV and PEDV was identified. For the STRING protein-protein interaction network, QAOA at circuit depth p = 3 reproduced the brute-force optimum with an approximation ratio of 1.000. In contrast, performance progressively declined in the denser co-expression network with increasing circuit depth, consistent with noise accumulation under current Noisy Intermediate-Scale Quantum (NISQ) conditions. Multi-run consensus analysis identified stable hub genes, including MMP9 and SLA-DOA, as well as genes exhibiting variable community assignments. CONCLUSION: These findings reveal a conserved macrophage suppression module shared between ASFV and PEDV and demonstrate that quantum computing can serve as an independent validation framework for biologically meaningful host-response networks. Network topology emerged as a key determinant of QAOA performance on real NISQ hardware.

Animals↗
PubMed1992

The structure and properties of liquid water: recent theoretical advances.

Computer simulations of water, and of water in the neighborhood of biological materials, are now commonplace. However, from the molecular physicist's viewpoint existing models of water/water, water/solute, and water/substrate interactions are incorrect and potentially misleading. Almost all existing simulations of biological interest assume that the molecules are rigid, or at least that the bonds do not vibrate. In this paper we review recent advances in the theory of water interactions, emphasizing the need to construct potential energy surfaces that include vibrational degrees of freedom.

Computer Simulation↗
PubMed1977

A reexamination of the problem of resonance energy transfer between DNA intercalated chromophores using bisintercalating compounds.

The rate of energy transfer between DNA intercalated ethidium cations calculated by Paoletti and Le Pecq1 using the Forster theory differs from the measured one by a factor of twenty two, if the proper geometrical factors are taken into account. By changing some of the parameters used in the calculation, the discrepancy can be reduced but not eliminated. This led us to the study of other systems where experimental and calculated results can be more directly compared. The apparent rate of energy transfer between ethidium and one of its non fluorescent analogues and between various pairs of intercalated chromophores has been studied. The fluorescence anisotropy decay of acridine dimers in glycerol or bisintercalated in DNA has been measured. These studies show that the Forster theory of energy transfer does not apply to the case of identical chromophores when they are relatively close to each other.

Acridines↗
PubMed1991

Probabilistic secretion of quanta in the central nervous system: granule cell synaptic control of pattern separation and activity regulation.

The implications of probabilistic secretion of quanta for the functioning of neural networks in the central nervous system have been explored. A model of stochastic secretion at synapses in simple networks, consisting of large numbers of granule cells and a relatively small number of inhibitory interneurons, has been analysed. Such networks occur in the input to the cerebellum Purkinje cells as well as to hippocampal CA3 pyramidal cells and to pyramidal cells in the visual cortex. In this model the input axons terminate on granule cells as well as on an inhibitory interneuron that projects to the granule cells. Stochastic secretion at these synapses involves both temporal variability in secretion at single synapses in the network as well as spatial variability in the secretion at different synapses. The role of this stochastic variability in controlling the size of the granule cell output to a level independent of the size of the input and in separating overlapping inputs has been determined analytically as well as by simulation. The regulation of granule-cell output activity to a reasonably constant value for different size inputs does not occur in the absence of an inhibitory interneuron when both spatial and temporal stochastic variability occurs at the remaining synapses; it is still very poor in the presence of such an interneuron but in the absence of stochastic variability. However, quite good regulation is achieved when the inhibitory interneuron is present with spatial and temporal stochastic variability of secretion at synapses in the network. Excellent regulation is achieved if, in addition, allowance is made for the nonlinear behaviour of the input-output characteristics of inhibitory interneurons. The capacity of granule-cell networks to separate overlapping patterns of activity on their inputs is adequate, with spatial variability in the secretion at synapses, but is improved if there is also temporal variability in the stochastic secretion at individual synapses, although this is at the expense of reliability in the network. Other factors which improve pattern separation are control of the output to very low activity levels, and a restriction on the cumulative size of the excitatory input terminals of each granule cell. Application of the theory to the input neural networks of the cerebellum and the hippocampus shows the role of stochastic variability in quantal transmission in determining the capacity of these networks for pattern separation and activity regulation.

Animals↗