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Science Advances Aug 2023The drift diffusion model (DDM) is a prominent account of how people make decisions. Many of these decisions involve comparing two alternatives based on differences of...
The drift diffusion model (DDM) is a prominent account of how people make decisions. Many of these decisions involve comparing two alternatives based on differences of perceived stimulus magnitudes, such as economic values. Here, we propose a consistent estimator for the parameters of a DDM in such cases. This estimator allows us to derive decision thresholds, drift rates, and subjective percepts (i.e., utilities in economic choice) directly from the experimental data. This eliminates the need to measure these values separately or to assume specific functional forms for them. Our method also allows one to predict drift rates for comparisons that did not occur in the dataset. We apply the method to two datasets, one comparing probabilities of earning a fixed reward and one comparing objects of variable reward value. Our analysis indicates that both datasets conform well to the DDM. We find that utilities are linear in probability and slightly convex in reward.
Topics: Humans; Diffusion; Income; Probability; Reward
PubMed: 37611107
DOI: 10.1126/sciadv.adf1665 -
Nature Communications Jan 2024Nanoscale optoelectrodes hold the potential to stimulate optically individual neurons and intracellular organelles, a challenge that demands both a high-density of...
Nanoscale optoelectrodes hold the potential to stimulate optically individual neurons and intracellular organelles, a challenge that demands both a high-density of photoelectron storage and significant charge injection. Here, we report that zinc porphyrin, commonly used in dye-sensitized solar cells, can be self-assembled into nanorods and then coated by TiO. The J-aggregated zinc porphyrin array enables long-range exciton diffusion and allows for fast electron transfer into TiO. The formation of TiO(e) attracts positive charges around the neuron membrane, contributing to the induction of action potentials. Far-field cranial irradiation of the motor cortex using a 670 nm laser or an 850 nm femtosecond laser can modulate local neuronal firing and trigger motor responses in the hind limb of mice. The pulsed photoelectrical stimulation of neurons in the subthalamic nucleus alleviates parkinsonian symptoms in mice, improving abnormal stepping and enhancing the activity of dopaminergic neurons. Our results suggest injectable nanoscopic optoelectrodes for optical neuromodulation with high efficiency and negligible side effects.
Topics: Animals; Mice; Action Potentials; Cranial Irradiation; Diffusion; Dopaminergic Neurons
PubMed: 38195782
DOI: 10.1038/s41467-023-44635-8 -
Magnetic Resonance in Medicine Mar 2024Brain cell structure and function reflect neurodevelopment, plasticity, and aging; and changes can help flag pathological processes such as neurodegeneration and...
Brain cell structure and function reflect neurodevelopment, plasticity, and aging; and changes can help flag pathological processes such as neurodegeneration and neuroinflammation. Accurate and quantitative methods to noninvasively disentangle cellular structural features are needed and are a substantial focus of brain research. Diffusion-weighted MRS (dMRS) gives access to diffusion properties of endogenous intracellular brain metabolites that are preferentially located inside specific brain cell populations. Despite its great potential, dMRS remains a challenging technique on all levels: from the data acquisition to the analysis, quantification, modeling, and interpretation of results. These challenges were the motivation behind the organization of the Lorentz Center workshop on "Best Practices & Tools for Diffusion MR Spectroscopy" held in Leiden, the Netherlands, in September 2021. During the workshop, the dMRS community established a set of recommendations to execute robust dMRS studies. This paper provides a description of the steps needed for acquiring, processing, fitting, and modeling dMRS data, and provides links to useful resources.
Topics: Consensus; Brain; Magnetic Resonance Spectroscopy; Diffusion; Diffusion Magnetic Resonance Imaging
PubMed: 37946584
DOI: 10.1002/mrm.29877 -
Toxins Sep 2023Blue-green algae, or cyanobacteria, may be prevalent in our rivers and tap water. These minuscule bacteria can grow swiftly and form blooms in warm, nutrient-rich water.... (Review)
Review
Blue-green algae, or cyanobacteria, may be prevalent in our rivers and tap water. These minuscule bacteria can grow swiftly and form blooms in warm, nutrient-rich water. Toxins produced by cyanobacteria can pollute rivers and streams and harm the liver and nervous system in humans. This review highlights the properties of 25 toxin types produced by 12 different cyanobacteria genera. The review also covered strategies for reducing and controlling cyanobacteria issues. These include using physical or chemical treatments, cutting back on fertilizer input, algal lawn scrubbers, and antagonistic microorganisms for biocontrol. Micro-, nano- and ultrafiltration techniques could be used for the removal of internal and extracellular cyanotoxins, in addition to powdered or granular activated carbon, ozonation, sedimentation, ultraviolet radiation, potassium permanganate, free chlorine, and pre-treatment oxidation techniques. The efficiency of treatment techniques for removing intracellular and extracellular cyanotoxins is also demonstrated. These approaches aim to lessen the risks of cyanobacterial blooms and associated toxins. Effective management of cyanobacteria in water systems depends on early detection and quick action. Cyanobacteria cells and their toxins can be detected using microscopy, molecular methods, chromatography, and spectroscopy. Understanding the causes of blooms and the many ways for their detection and elimination will help the management of this crucial environmental issue.
Topics: Humans; Drinking Water; Lakes; Ultraviolet Rays; Diffusion; Cyanobacteria Toxins
PubMed: 37756009
DOI: 10.3390/toxins15090582 -
Journal of Controlled Release :... Feb 2024Drug delivery systems which rely on diffusion for mass transport, such as hydrogels and nanoparticles, have enhanced drug targeting and extended delivery profiles to... (Review)
Review
Drug delivery systems which rely on diffusion for mass transport, such as hydrogels and nanoparticles, have enhanced drug targeting and extended delivery profiles to improve health outcomes for patients suffering from diseases including cancer and diabetes. However, diffusion-dependent systems often fail to provide >0.01-1% drug bioavailability when transporting macromolecules across poorly permeable physiological tissues such as the skin, solid tumors, the blood-brain barrier, and the gastrointestinal walls. Convection-enabling robotic ingestibles, wearables, and implantables physically interact with tissue walls to improve bioavailability in these settings by multiple orders of magnitude through convective mass transfer, the process of moving drug molecules via bulk fluid flow. In this Review, we compare diffusive and convective drug delivery systems, highlight engineering techniques that enhance the efficacy of convective devices, and provide examples of synergies between the two methods of drug transport.
Topics: Humans; Diffusion; Biological Transport; Drug Delivery Systems; Blood-Brain Barrier; Neoplasms
PubMed: 38190971
DOI: 10.1016/j.jconrel.2024.01.008 -
Lab on a Chip Apr 2024Tumor spheroids are now intensively investigated toward preclinical and clinical applications, necessitating the establishment of accessible and cost-effective methods...
Tumor spheroids are now intensively investigated toward preclinical and clinical applications, necessitating the establishment of accessible and cost-effective methods for routine operations. Without losing the advantage of organ-chip technologies, we developed a rocking system for facile formation and culture of tumor spheroids in hydrogel microwells of a suspended membrane under microfluidic conditions. While the rocking is controlled with a step motor, the microfluidic device is made of two plastic plates, allowing plugging directly syringe tubes with Luer connectors. Upon injection of the culture medium into the tubes and subsequent rocking of the chip, the medium flows back and forth in the channel underneath the membrane, ensuring a diffusion-based culture. Our results showed that such a rocking- and diffusion-based culture method significantly improved the quality of the tumor spheroids when compared to the static culture, particularly in terms of growth rate, roundness, junction formation and compactness of the spheroids. Notably, dynamically cultured tumor spheroids showed increased drug resistance, suggesting alternative assay conditions. Overall, the present method is pumpless, connectionless, and user-friendly, thereby facilitating the advancement of tumor-spheroid-based applications.
Topics: Spheroids, Cellular; Humans; Lab-On-A-Chip Devices; Cell Culture Techniques; Diffusion; Microfluidic Analytical Techniques; Hydrogels; Cell Line, Tumor; Tumor Cells, Cultured; Equipment Design
PubMed: 38629978
DOI: 10.1039/d3lc01116j -
Japanese Journal of Radiology Nov 2023This study aimed to evaluate the along the perivascular space (ALPS) index based on the diffusion tensor image ALPS (DTI-ALPS) in corticobasal degeneration with...
PURPOSE
This study aimed to evaluate the along the perivascular space (ALPS) index based on the diffusion tensor image ALPS (DTI-ALPS) in corticobasal degeneration with corticobasal syndrome (CBD-CBS) and investigate its correlation with motor and cognitive functions.
MATERIALS AND METHODS
The data of 21 patients with CBD-CBS and 17 healthy controls (HCs) were obtained from the 4-Repeat Tauopathy Neuroimaging Initiative and the Frontotemporal Lobar Degeneration Neuroimaging Initiative databases. Diffusion magnetic resonance imaging was performed using a 3-Tesla MRI scanner. The ALPS index based on DTI-ALPS was automatically calculated after preprocessing. The ALPS index was compared between the CBD-CBS and HC groups via a general linear model analysis, with covariates such as age, sex, years of education, and intracranial volume (ICV). Furthermore, to confirm the relation between the ALPS index and the motor and cognitive score in CBD-CBS, the partial Spearman's rank correlation coefficient was calculated with covariates such as age, sex, years of education, and ICV. A p value of < 0.05 was considered as statistically significant in all statistical analyses.
RESULTS
The ALPS index of CBD-CBS was significantly lower than that of HC (Cohen's d = - 1.53, p < 0.005). Moreover, the ALPS index had a significant positive correlation with the mini mental state evaluation score (r = 0.65, p < 0.005) and a significant negative correlation with the unified Parkinson's Disease Rating Scale III score (r = - 0.75, p < 0.001).
CONCLUSION
The ALPS index of patients with CBD-CBS, which is significantly lower than that of HCs, is significantly associated with motor and cognitive functions.
Topics: Humans; Corticobasal Degeneration; Glymphatic System; Databases, Factual; Diffusion; Diffusion Magnetic Resonance Imaging
PubMed: 37273112
DOI: 10.1007/s11604-023-01454-7 -
Environmental Science & Technology Nov 2023The development of energy-efficient and environmentally friendly lithium extraction techniques is essential to meet the growing global demand for lithium-ion batteries....
The development of energy-efficient and environmentally friendly lithium extraction techniques is essential to meet the growing global demand for lithium-ion batteries. In this work, a dual-channel ion conductor membrane was designed for a concentration-driven lithium-selective ion diffusion process. The membrane was based on a porous lithium-ion conductor, and its pores were modified with an anion-exchange polymer. Thus, the sintered lithium-ion conductors provided highly selective cation transport channels, and the functionalized nanopores with positive charges enabled the complementary permeation of anions to balance the transmembrane charges. As a result, the dual-channel membrane realized an ultrahigh Li/Na selectivity of ∼1389 with a competitive Li flux of 21.6 mmol·m·h in a diffusion process of the LiCl/NaCl binary solution, which was capable of further maintaining the high selectivity over 7 days of testing. Therefore, this work demonstrates the great potential of the dual-channel membrane design for high-performing lithium extraction from aqueous resources with low energy consumption and minimal environmental impact.
Topics: Lithium; Sodium; Diffusion
PubMed: 37918342
DOI: 10.1021/acs.est.3c05935 -
Japanese Journal of Radiology Dec 2023This study aimed to evaluate the relationship between sleep quality as assessed using the Pittsburgh Sleep Quality Index (PSQI) and the index of diffusivity along the...
PURPOSE
This study aimed to evaluate the relationship between sleep quality as assessed using the Pittsburgh Sleep Quality Index (PSQI) and the index of diffusivity along the perivascular space (ALPS index), a possible indirect indicator of glymphatic system activity.
MATERIALS AND METHODS
This study included the diffusion magnetic resonance imaging (MRI) data of 317 people with sleep disruption and 515 healthy controls (HCs) from the Human Connectome Project (WU-MINN HCP 1200). The ALPS index was calculated automatically based on diffusion tensor image analysis (DTI)-ALPS of diffusion MRI. The ALPS index of the sleep disruption and HC groups was compared using general linear model (GLM) analysis with covariates, such as age, sex, level of education, and intracranial volume. In addition, to confirm the relationship between sleep quality and the ALPS index in the sleep disruption group as well as evaluate the effect of each PSQI component on the ALPS index, correlation analyses between the ALPS indices and PSQI scores of all the components and between the ALPS index and each PSQI component was performed using GLM analysis with the abovementioned covariates, respectively.
RESULTS
The ALPS index was significantly lower in the sleep disruption group than in the HC group (p = 0.001). Moreover, the ALPS indices showed significant negative correlations with the PSQI scores of all the components (false discovery rate [FDR]-corrected p < 0.001). Two significant negative correlations were also found between the ALPS index and PSQI component 2 (sleep latency, FDR-corrected p < 0.001) and 6 (the use of sleep medication, FDR-corrected p < 0.001).
CONCLUSION
Our findings suggest that glymphatic system impairment contributes to sleep disruption in young adults.
Topics: Young Adult; Humans; Glymphatic System; Sleep; Diffusion; Diffusion Magnetic Resonance Imaging; Image Processing, Computer-Assisted
PubMed: 37368182
DOI: 10.1007/s11604-023-01463-6 -
Journal of the Royal Society, Interface Feb 2024We link continuum models of reaction-diffusion systems that exhibit diffusion-driven instability to constraints on the particle-scale interactions underpinning this...
We link continuum models of reaction-diffusion systems that exhibit diffusion-driven instability to constraints on the particle-scale interactions underpinning this instability. While innumerable biological, chemical and physical patterns have been studied through the lens of Alan Turing's reaction-diffusion pattern-forming mechanism, the connections between models of pattern formation and the nature of the particle interactions generating them have been relatively understudied in comparison with the substantial efforts that have been focused on understanding proposed continuum systems. To derive the necessary reactant combinations for the most parsimonious reaction schemes, we analyse the emergent continuum models in terms of possible generating elementary reaction schemes. This analysis results in the complete list of such schemes containing the fewest reactions; these are the simplest possible hypothetical mass-action models for a pattern-forming system of two interacting species.
Topics: Models, Biological; Diffusion
PubMed: 38412962
DOI: 10.1098/rsif.2023.0490