The Effect of Connecting Bridges on Vortex-induced Vibration of Skyscrapers

The shapes of slender skyscrapers are unfavourable for carrying horizontal loads. In this paper, we investigate the possibility of improving their structural behaviour by adding urban-scale networks of structural connections among the buildings. We focus on vibrations of skyscrapers in response to wind-induced vortex shedding. We develop a conceptual model of those structural networks composed of springs, dampers and point masses. The proposed model enables rapid numerical simulations involving large networks, which is not possible in the case of more detailed engineering models. The effect of connections, dilatation gaps, and network size are investigated for random collections of high-rise buildings, and triangular networks of horizontal bar connections among them. It is found that connections efficiently reduce vibrations in the network, especially for large network size. This study aims to be a first step towards uncovering the benefits of a novel form of urban development. A karcsú felhőkarcolók alakja kedvezőtlen a rájuk ható vízszintes terhek viselése szempontjából. Munkánkban a szerkezeti viselkedés javítási lehetőségeit vizsgáljuk az épületeket összekötő szerkezeti kapcsolatok városi léptékű hálózata segítségével. Vizsgálatunk középpontjában a szél által kiváltott örvényleválás okozta szerkezeti rezgések állnak. A rendszert rugókból, csillapítóelemekből és tömegpontokból álló koncepcionális modell segítségével írjuk le. Ez a megközelítésmód lehetővé teszi nagy hálózatok gyors numerikus szimulációját, amely részletesebb mérnöki modellek esetében nem lehetséges. Véletlenszerűen generált épületcsoportok, és vízszintes rúdszerű kapcsolatokból kialakított háromszögelt hálózatok esetén vizsgáljuk a kapcsolatoknak, a bennük kialakított dilatációs hézagoknak és a hálózat méretének a hatását. Eredményeink azt mutatják, hogy a kapcsolatok jelentősen csökkentik a hálózat rezgéseit, különösen nagy hálózati méret esetén. A tanulmány célja, hogy kezdeti lépéseket tegyünk egy újszerű városfejlesztési modell előnyeinek feltárására.

Cortical-subcortical structural connections support transcranial magnetic stimulation engagement of the amygdala

The amygdala processes valenced stimuli, influences affective states, and exhibits aberrant activity across anxiety disorders, depression, and PTSD. Interventions that modulate amygdala activity hold promise for treating transdiagnostic affective symptoms. We investigated (N=45) whether transcranial magnetic stimulation (TMS) elicits indirect changes in amygdala activity when applied to ventrolateral prefrontal cortex (vlPFC), a region important for affect regulation. Harnessing in-scanner interleaved TMS/functional MRI (fMRI), we reveal that vlPFC neurostimulation evoked acute, dose-dependent modulations of amygdala fMRI BOLD signal. Larger TMS-evoked changes in amygdala fMRI signal were associated with higher fiber density in a vlPFC-amygdala white matter pathway, suggesting this pathway facilitated stimulation-induced communication between cortex and subcortex. This work provides evidence of amygdala engagement by TMS, highlighting stimulation of vlPFC-amygdala circuits as a candidate treatment for affective psychopathology. More broadly, it indicates that targeting cortical-subcortical connections may enhance the impact of TMS on subcortical neural activity and, by extension, subcortex-subserved behaviors.

Benchmarking functional connectivity by the structure and geometry of the human brain

The brain’s structural connectivity supports the propagation of electrical impulses, manifesting as patterns of co-activation, termed functional connectivity. Functional connectivity emerges from the underlying sparse structural connections, particularly through poly-synaptic communication. As a result, functional connections between brain regions without direct structural links are numerous, but their organization is not completely understood. Here we investigate the organization of functional connections without direct structural links. We develop a simple, data-driven method to benchmark functional connections with respect to their underlying structural and geometric embedding. We then use this method to re-weigh and re-express functional connectivity. We find evidence of unexpectedly strong functional connectivity within the canonical intrinsic networks of the brain. We also find unexpectedly strong functional connectivity at the apex of the unimodal-transmodal hierarchy. Our results suggest that both phenomena – functional modules and functional hierarchies – emerge from functional interactions that transcend the underlying structure and geometry. These findings also potentially explain recent reports that structural and functional connectivity gradually diverge in transmodal cortex. Collectively, we show how structural connectivity and geometry can be used as a natural frame of reference with which to study functional connectivity patterns in the brain.

Joint Analysis of Functional and Structural Connectomes Between Preterm and Term Infant Brains via Canonical Correlation Analysis With Locality Preserving Projection

Preterm is a worldwide problem that affects infants’ lives significantly. Moreover, the early impairment is more than limited to isolated brain regions but also to global and profound negative outcomes later, such as cognitive disorder. Therefore, seeking the differences of brain connectome between preterm and term infant brains is a vital step for understanding the developmental impairment caused by preterm. Existing studies revealed that studying the relationship between brain function and structure, and further investigating their differentiable connectomes between preterm and term infant brains is a way to comprehend and unveil the differences that occur in the preterm infant brains. Therefore, in this article, we proposed a novel canonical correlation analysis (CCA) with locality preserving projection (LPP) approach to investigate the relationship between brain functional and structural connectomes and how such a relationship differs between preterm and term infant brains. CCA is proposed to study the relationship between functional and structural connections, while LPP is adopted to identify the distinguishing features from the connections which can differentiate the preterm and term brains. After investigating the whole brain connections on a fine-scale connectome approach, we successfully identified 89 functional and 97 structural connections, which mostly contributed to differentiate preterm and term infant brains from the functional MRI (fMRI) and diffusion MRI (dMRI) of the public developing Human Connectome Project (dHCP) dataset. By further exploring those identified connections, the results innovatively revealed that the identified functional connections are short-range and within the functional network. On the contrary, the identified structural connections are usually remote connections across different functional networks. In addition, these connectome-level results show the new insights that longitudinal functional changes could deviate from longitudinal structural changes in the preterm infant brains, which help us better understand the brain-behavior changes in preterm infant brains.

Heritability and interindividual variability of regional structure-function coupling

White matter structural connections are likely to support flow of functional activation or functional connectivity. While the relationship between structural and functional connectivity profiles, here called SC-FC coupling, has been studied on a whole-brain, global level, few studies have investigated this relationship at a regional scale. Here we quantify regional SC-FC coupling in healthy young adults using diffusion-weighted MRI and resting-state functional MRI data from the Human Connectome Project and study how SC-FC coupling may be heritable and varies between individuals. We show that regional SC-FC coupling strength varies widely across brain regions, but was strongest in highly structurally connected visual and subcortical areas. We also show interindividual regional differences based on age, sex and composite cognitive scores, and that SC-FC coupling was highly heritable within certain networks. These results suggest regional structure-function coupling is an idiosyncratic feature of brain organisation that may be influenced by genetic factors.

A single mode of population covariation associates brain networks structure and behavior and predicts individual subjects’ age

Multiple human behaviors improve early in life, peaking in young adulthood, and declining thereafter. Several properties of brain structure and function progress similarly across the lifespan. Cognitive and neuroscience research has approached aging primarily using associations between a few behaviors, brain functions, and structures. Because of this, the multivariate, global factors relating brain and behavior across the lifespan are not well understood. We investigated the global patterns of associations between 334 behavioral and clinical measures and 376 brain structural connections in 594 individuals across the lifespan. A single-axis associated changes in multiple behavioral domains and brain structural connections (r = 0.5808). Individual variability within the single association axis well predicted the age of the subject (r = 0.6275). Representational similarity analysis evidenced global patterns of interactions across multiple brain network systems and behavioral domains. Results show that global processes of human aging can be well captured by a multivariate data fusion approach.

Biophysical network models of phase-synchronization in MEG resting-state

Magnetoencephalography (MEG) is used extensively to study functional connectivity (FC) networks of phase-synchronization, but the relationship of these networks to their biophysical substrates is poorly understood. Biophysical Network Models (BNMs) have been used to produce networks corresponding to MEG-derived networks of phase-synchronization, but the roles of inter-regional conduction delays, the structural connectome and dynamics of model of individual brain regions, in obtaining this correspondence remain unknown. In this study, we investigated the roles of conduction delays, the structural connectome, and dynamics of models of individual regions, in obtaining a correspondence between model-generated and MEG-derived networks between left-hemispheric regions. To do this, we compared three BNMs, respectively comprising Wilson-Cowan oscillators interacting with diffusion Magnetic Resonance Imaging (MRI)-based patterns of structural connections through zero delays, constant delays and distance-dependent delays respectively. For the BNM whose networks corresponded most closely to the MEG-derived network, we used comparisons against null models to identify specific features of each model component, e.g. the pattern of connections in the structure connectome, that contributed to the observed correspondence. The Wilson-Cowan zero delays model produced networks with a closer correspondence to the MEG-derived network than those produced by the constant delays model, and the same as those produced by the distance-dependent delays model. Hence, there is no evidence that including conduction delays improves the correspondence between model-generated and MEG-derived networks. Given this, we chose the Wilson-Cowan zero delays model for further investigation. Comparing the Wilson-Cowan zero delays model against null models revealed that both the pattern of structural connections and Wilson-Cowan oscillatory dynamics contribute to the correspondence between model-generated and MEG-derived networks. Our investigations yield insight into the roles of conduction delays, the structural connectome and dynamics of models of individual brain regions, in obtaining a correspondence between model-generated and MEG-derived networks. These findings result in a parsimonious BNM that produces networks corresponding closely to MEG-derived networks of phase-synchronization.

Designing a steel connection with a high degree of disassembly: a practice-based experience

This article is derived from a feasibility study for a single-story elevation at the Kent School of Architecture and Planning (KSAP) in the United Kingdom. This project embraced two fundamental principles of the circular economy: flexibility of interior spaces and Design for Disassembly (DfD). The goals were to reduce the risk of demolition and preserve the value of the building material to empower its later use. These principles formed the solution for the structural frame. For this paper, the engineering phase was carried out to improve the structural connections designed according to DfD principles and following generative design methods.

Scanning Electron Microscopic Study of the White Pulp of Spleen in Adult Goats

The white pulp of the spleen in adult goats was thoroughly screened under the scanning electron microscope (VEGA3 TESCAN). The study revealed the presence of lymphoid and non-lymphoid cells. The T lymphocytes and B lymphocytes could morphologically be differentiated under the magnification of 8000 to 20000 times by Scanning electron microscopy. The changes in number of cells in relation to the age was also recorded. The peri arterial lymphatic sheath and its structural connections with Reticular cells and other non-lymphoid cells were clearly demonstrated. The types of lymphoid cells and their arrangement around the central arteries upto the marginal zones were observed in detail. A conclusion about the type of circulation in the spleen of goats was arrived after three dimentional observation of the tissue under scanning electron microscope.