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ACS Omega Jun 2024A novel thermosetting preceramic resin called acrylate-grafted liquid polysilazane (ALSZ) was readily synthesized. The curing behaviors of ALSZ were investigated by the...
A novel thermosetting preceramic resin called acrylate-grafted liquid polysilazane (ALSZ) was readily synthesized. The curing behaviors of ALSZ were investigated by the techniques of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and rheological tests. The catalytic thermocuring process was controlled by the addition of a polymerization accelerator composed of a radical initiator (cumene hydroperoxide) and a transition metal catalyst (nickel naphthenate or cobalt naphthenate). Photocuring at room temperature can proceed readily by the addition of photosensitizer 819 (phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide). By combining a radical initiator, a transition metal catalyst, and a photosensitizer, synergistic photothermocuring was achieved, demonstrating advantages such as material shaping at room temperature and low weight loss during curing. The ceramization of the solidified ceramic precursors in an Ar atmosphere was studied using TGA and tube furnace pyrolysis. ALSZs exhibited comparatively high ceramic transformation yields (71-75% at 800 °C). The resulting pyrolytic ceramics maintained their original shape without deformation or foaming expansion. Polysilazanes containing acrylate groups can directly form casting bodies, showing a high static glass transition temperature (>380 °C) by thermomechanical analysis (TMA). FT-IR analyses revealed that multiple reactions are involved in the curing of ALSZ. The results in this paper showed that ALSZ might find prospective applications in material processing, such as additive manufacturing and ceramic-matrix composites.
PubMed: 38882088
DOI: 10.1021/acsomega.4c02018 -
Journal of Biomedical Informatics Jun 2024Art. 50 of the proposal for a Regulation on the European Health Data Space (EHDS) states that "health data access bodies shall provide access to electronic health data...
BACKGROUND
Art. 50 of the proposal for a Regulation on the European Health Data Space (EHDS) states that "health data access bodies shall provide access to electronic health data only through a secure processing environment, with technical and organizational measures and security and interoperability requirements".
OBJECTIVE
To identify specific security measures that nodes participating in health data spaces shall implement based on the results of the IMPaCT-Data project, whose goal is to facilitate the exchange of electronic health records (EHR) between public entities based in Spain and the secondary use of this information for precision medicine research in compliance with the General Data Protection Regulation (GDPR).
DATA AND METHODS
This article presents an analysis of 24 out of a list of 72 security measures identified in the Spanish National Security Scheme (ENS) and adopted by members of the federated data infrastructure developed during the IMPaCT-Data project.
RESULTS
The IMPaCT-Data case helps clarify roles and responsibilities of entities willing to participate in the EHDS by reconciling technical system notions with the legal terminology. Most relevant security measures for Data Space Gatekeepers, Enablers and Prosumers are identified and explained.
CONCLUSION
The EHDS can only be viable as long as the fiduciary duty of care of public health authorities is preserved; this implies that the secondary use of personal data shall contribute to the public interest and/or to protect the vital interests of the data subjects. This condition can only be met if all nodes participating in a health data space adopt the appropriate organizational and technical security measures necessary to fulfill their role.
PubMed: 38880235
DOI: 10.1016/j.jbi.2024.104670 -
Learning & Memory (Cold Spring Harbor,... May 2024The common fruit fly provides a powerful platform to investigate the genetic, molecular, cellular, and neural circuit mechanisms of behavior. Research in this model... (Review)
Review
The common fruit fly provides a powerful platform to investigate the genetic, molecular, cellular, and neural circuit mechanisms of behavior. Research in this model system has shed light on multiple aspects of brain physiology and behavior, from fundamental neuronal function to complex behaviors. A major anatomical region that modulates complex behaviors is the mushroom body (MB). The MB integrates multimodal sensory information and is involved in behaviors ranging from sensory processing/responses to learning and memory. Many genes that underlie brain disorders are conserved, from flies to humans, and studies in have contributed significantly to our understanding of the mechanisms of brain disorders. Genetic mutations that mimic human diseases-such as Fragile X syndrome, neurofibromatosis type 1, Parkinson's disease, and Alzheimer's disease-affect MB structure and function, altering behavior. Studies dissecting the effects of disease-causing mutations in the MB have identified key pathological mechanisms, and the development of a complete connectome promises to add a comprehensive anatomical framework for disease modeling. Here, we review models of human neurodevelopmental and neurodegenerative disorders via the effects of their underlying mutations on MB structure, function, and the resulting behavioral alterations.
Topics: Animals; Mushroom Bodies; Disease Models, Animal; Neurodegenerative Diseases; Neurodevelopmental Disorders; Drosophila melanogaster; Humans; Drosophila
PubMed: 38876485
DOI: 10.1101/lm.053816.123 -
Cerebral Cortex (New York, N.Y. : 1991) Jun 2024The amygdala is present in a diverse range of vertebrate species, such as lizards, rodents, and primates; however, its structure and connectivity differs across species....
The amygdala is present in a diverse range of vertebrate species, such as lizards, rodents, and primates; however, its structure and connectivity differs across species. The increased connections to visual sensory areas in primate species suggests that understanding the visual selectivity of the amygdala in detail is critical to revealing the principles underlying its function in primate cognition. Therefore, we designed a high-resolution, contrast-agent enhanced, event-related fMRI experiment, and scanned 3 adult rhesus macaques, while they viewed 96 naturalistic stimuli. Half of these stimuli were social (defined by the presence of a conspecific), the other half were nonsocial. We also nested manipulations of emotional valence (positive, neutral, and negative) and visual category (faces, nonfaces, animate, and inanimate) within the stimulus set. The results reveal widespread effects of emotional valence, with the amygdala responding more on average to inanimate objects and animals than faces, bodies, or social agents in this experimental context. These findings suggest that the amygdala makes a contribution to primate vision that goes beyond an auxiliary role in face or social perception. Furthermore, the results highlight the importance of stimulus selection and experimental design when probing the function of the amygdala and other visually responsive brain regions.
Topics: Animals; Amygdala; Macaca mulatta; Magnetic Resonance Imaging; Male; Photic Stimulation; Emotions; Brain Mapping; Visual Perception; Female; Pattern Recognition, Visual
PubMed: 38864574
DOI: 10.1093/cercor/bhae245 -
Learning & Memory (Cold Spring Harbor,... May 2024Across animal species, dopamine-operated memory systems comprise anatomically segregated, functionally diverse subsystems. Although individual subsystems could operate... (Review)
Review
Across animal species, dopamine-operated memory systems comprise anatomically segregated, functionally diverse subsystems. Although individual subsystems could operate independently to support distinct types of memory, the logical interplay between subsystems is expected to enable more complex memory processing by allowing existing memory to influence future learning. Recent comprehensive ultrastructural analysis of the mushroom body revealed intricate networks interconnecting the dopamine subsystems-the mushroom body compartments. Here, we review the functions of some of these connections that are beginning to be understood. Memory consolidation is mediated by two different forms of network: A recurrent feedback loop within a compartment maintains sustained dopamine activity required for consolidation, whereas feed-forward connections across compartments allow short-term memory formation in one compartment to open the gate for long-term memory formation in another compartment. Extinction and reversal of aversive memory rely on a similar feed-forward circuit motif that signals omission of punishment as a reward, which triggers plasticity that counteracts the original aversive memory trace. Finally, indirect feed-forward connections from a long-term memory compartment to short-term memory compartments mediate higher-order conditioning. Collectively, these emerging studies indicate that feedback control and hierarchical connectivity allow the dopamine subsystems to work cooperatively to support diverse and complex forms of learning.
Topics: Animals; Dopamine; Mushroom Bodies; Drosophila; Feedback, Physiological; Memory Consolidation; Nerve Net; Dopaminergic Neurons; Neural Pathways
PubMed: 38862171
DOI: 10.1101/lm.053807.123 -
Brain, Behavior and Evolution Jun 2024Social experience early in life appears to be necessary for the development of species-typical behavior. Although isolation during critical periods of maturation has...
INTRODUCTION
Social experience early in life appears to be necessary for the development of species-typical behavior. Although isolation during critical periods of maturation has been shown to impact behavior by altering gene expression and brain development in invertebrates and vertebrates, workers of some ant species appear resilient to social deprivation and other neurobiological challenges that occur during senescence or due to loss of sensory input. It is unclear if and to what degree neuroanatomy, neurochemistry, and behavior will show deficiencies if social experience in the early adult life of worker ants is compromised.
METHODS
We reared newly-eclosed adult workers of Camponotus floridanus under conditions of social isolation for 2 to 53 days, quantified brain compartment volumes, recorded biogenic amine levels in individual brains, and evaluated movement and behavioral performance to compare the neuroanatomy, neurochemistry, brood-care behavior, and foraging (predatory behavior) of isolated workers with that of workers experiencing natural social contact after adult eclosion.
RESULTS
We found that the volume of the antennal lobe, which processes olfactory inputs, was significantly reduced in workers isolated for an average of 40 days, whereas the size of the mushroom bodies, centers of higher-order sensory processing, increased after eclosion and was not significantly different from controls. Titers of the neuromodulators serotonin, dopamine, and octopamine remained stable and were not significantly different in isolation treatments and controls. Brood care, predation, and overall movement were reduced in workers lacking social contact early in life.
CONCLUSION
These results suggest that the behavioral development of isolated workers of C. floridanus is specifically impacted by a reduction in the size of the antennal lobe. Task performance and locomotor ability therefore appear to be sensitive to a loss of social contact through a reduction of olfactory processing ability rather than change in the size of the mushroom bodies, which serve important functions in learning and memory, or the central complex, which controls movement.
PubMed: 38857586
DOI: 10.1159/000539546 -
Applied Optics May 20243D printing technologies have distinguished advantages in manufacturing arbitrary shapes and complex structures that have attracted us to use digital light processing...
3D printing technologies have distinguished advantages in manufacturing arbitrary shapes and complex structures that have attracted us to use digital light processing (DLP) technology for specialty silica optical fiber preforms. One of the main tasks is to develop an appropriate recipe for DLP resin that is UV sensitive and loaded with silica nanoparticles. In this work, the effects of a UV absorber in highly silica-loaded resin on DLP printing are experimentally investigated. Spot tests and DLP printing are carried out on resins with varying dosages of a typical UV absorber, Sudan Orange G. Based on the experimental results, the UV absorber can significantly improve the resolution of DLP printed green bodies while requiring a larger exposure dose.
PubMed: 38856327
DOI: 10.1364/AO.516246 -
Philosophical Transactions of the Royal... Jul 2024Commentaries about long-term potentiation (LTP) generally proceed with an implicit assumption that largely the same physiological effect is sampled across different... (Review)
Review
Commentaries about long-term potentiation (LTP) generally proceed with an implicit assumption that largely the same physiological effect is sampled across different experiments. However, this is clearly not the case. We illustrate the point by comparing LTP in the CA3 projections to CA1 with the different forms of potentiation in the dentate gyrus. These studies lead to the hypothesis that specialized properties of CA1-LTP are adaptations for encoding unsupervised learning and episodic memory, whereas the dentate gyrus variants subserve learning that requires multiple trials and separation of overlapping bodies of information. Recent work has added sex as a second and somewhat surprising dimension along which LTP is also differentiated. Triggering events for CA1-LTP differ between the sexes and the adult induction threshold is significantly higher in females; these findings help explain why males have an advantage in spatial learning. Remarkably, the converse is true before puberty: Females have the lower LTP threshold and are better at spatial memory problems. A mechanism has been identified for the loss-of-function in females but not for the gain-of-function in males. We propose that the many and disparate demands of natural environments, with different processing requirements across ages and between sexes, led to the emergence of multiple LTPs. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
Topics: Animals; Female; Humans; Male; CA1 Region, Hippocampal; CA3 Region, Hippocampal; Dentate Gyrus; Long-Term Potentiation; Memory; Sex Factors
PubMed: 38853551
DOI: 10.1098/rstb.2023.0223 -
NeuroImage Jun 2024Brain disorders are often associated with changes in brain structure and function, where functional changes may be due to underlying structural variations. Gray matter...
Brain disorders are often associated with changes in brain structure and function, where functional changes may be due to underlying structural variations. Gray matter (GM) volume segmentation from 3D structural MRI offers vital structural information for brain disorders like schizophrenia, as it encompasses essential brain tissues such as neuronal cell bodies, dendrites, and synapses, which are crucial for neural signal processing and transmission; changes in GM volume can thus indicate alterations in these tissues, reflecting underlying pathological conditions. In addition, the use of the ICA algorithm to transform high-dimensional fMRI data into functional network connectivity (FNC) matrices serves as an effective carrier of functional information. In our study, we introduce a new generative deep learning architecture, the conditional efficient vision transformer generative adversarial network (cEViT-GAN), which adeptly generates FNC matrices conditioned on GM to facilitate the exploration of potential connections between brain structure and function. We developed a new, lightweight self-attention mechanism for our ViT-based generator, enhancing the generation of refined attention maps critical for identifying structural biomarkers based on GM. Our approach not only generates high quality FNC matrices with a Pearson correlation of 0.74 compared to real FNC data, but also uses attention map technology to identify potential biomarkers in GM structure that could lead to functional abnormalities in schizophrenia patients. Visualization experiments within our study have highlighted these structural biomarkers, including the medial prefrontal cortex (mPFC), dorsolateral prefrontal cortex (DL-PFC), and cerebellum. In addition, through cross-domain analysis comparing generated and real FNC matrices, we have identified functional connections with the highest correlations to structural information, further validating the structure-function connections. This comprehensive analysis helps to understand the intricate relationship between brain structure and its functional manifestations, providing a more refined insight into the neurobiological research of schizophrenia.
PubMed: 38851549
DOI: 10.1016/j.neuroimage.2024.120674 -
Frontiers in Physiology 2024Ants are capable of learning long visually guided foraging routes with limited neural resources. The visual scene memory needed for this behaviour is mediated by the...
Ants are capable of learning long visually guided foraging routes with limited neural resources. The visual scene memory needed for this behaviour is mediated by the mushroom bodies; an insect brain region important for learning and memory. In a visual navigation context, the mushroom bodies are theorised to act as familiarity detectors, guiding ants to views that are similar to those previously learned when first travelling along a foraging route. Evidence from behavioural experiments, computational studies and brain lesions all support this idea. Here we further investigate the role of mushroom bodies in visual navigation with a spiking neural network model learning complex natural scenes. By implementing these networks in GeNN-a library for building GPU accelerated spiking neural networks-we were able to test these models offline on an image database representing navigation through a complex outdoor natural environment, and also online embodied on a robot. The mushroom body model successfully learnt a large series of visual scenes (400 scenes corresponding to a 27 m route) and used these memories to choose accurate heading directions during route recapitulation in both complex environments. Through analysing our model's Kenyon cell (KC) activity, we were able to demonstrate that KC activity is directly related to the respective novelty of input images. Through conducting a parameter search we found that there is a non-linear dependence between optimal KC to visual projection neuron (VPN) connection sparsity and the length of time the model is presented with an image stimulus. The parameter search also showed training the model on lower proportions of a route generally produced better accuracy when testing on the entire route. We embodied the mushroom body model and comparator visual navigation algorithms on a Quanser Q-car robot with all processing running on an Nvidia Jetson TX2. On a 6.5 m route, the mushroom body model had a mean distance to training route (error) of 0.144 ± 0.088 m over 5 trials, which was performance comparable to standard visual-only navigation algorithms. Thus, we have demonstrated that a biologically plausible model of the ant mushroom body can navigate complex environments both in simulation and the real world. Understanding the neural basis of this behaviour will provide insight into how neural circuits are tuned to rapidly learn behaviourally relevant information from complex environments and provide inspiration for creating bio-mimetic computer/robotic systems that can learn rapidly with low energy requirements.
PubMed: 38841209
DOI: 10.3389/fphys.2024.1379977