4 research outputs found
Reduced apparent fiber density in the white matter of premature-born adults
Premature-born adults exhibit lasting white matter alterations as demonstrated by widespread reduction in fractional anisotropy (FA) based on diffusion-weighted imaging (DWI). FA reduction, however, is non-specific for microscopic underpinnings such as aberrant myelination or fiber density (FD). Using recent advances in DWI, we tested the hypothesis of reduced FD in premature-born adults and investigated its link with the degree of prematurity and cognition. 73 premature- and 89 mature-born adults aged 25–27 years underwent single-shell DWI, from which a FD measure was derived using convex optimization modeling for microstructure informed tractography (COMMIT). Premature-born adults exhibited lower FD in numerous tracts including the corpus callosum and corona radiata compared to mature-born adults. These FD alterations were associated with both the degree of prematurity, as assessed via gestational age and birth weight, as well as with reduced cognition as measured by full-scale IQ. Finally, lower FD overlapped with lower FA, suggesting lower FD underlie unspecific FA reductions. Results provide evidence that premature birth leads to lower FD in adulthood which links with lower full-scale IQ. Data suggest that lower FD partly underpins FA reductions of premature birth but that other processes such as hypomyelination might also take place
Communication and Computation by Bacteria Compartmentalized within Microemulsion Droplets
Amphiphilic
inducer molecules such as <i>N</i>-acyl-l-homoserine
lactones (AHLs) or isopropyl-β-d-thio-galactopyranoside
(IPTG) can be utilized for the implementation
of an artificial communication system between groups of <i>E.
coli</i> bacteria encapsulated within water-in-oil microemulsion
droplets. Using spatially extended arrays of microdroplets, we study
the diffusion of both AHL and IPTG from inducer-filled reservoirs
into bacteria-containing droplets, and also from droplets with AHL
producing sender bacteria into neighboring droplets containing receiver
cells. Computational modeling of gene expression dynamics within the
droplets suggests a strongly reduced effective diffusion coefficient
of the inducers, which markedly affects the spatial communication
pattern in the neighborhood of the senders. Engineered bacteria that
integrate AHL and IPTG signals with a synthetic AND gate gene circuit
are shown to respond only in the presence of both types of sender
droplets, which demonstrates the potential of the system for genetically
programmed pattern formation and distributed computing
Communication and Computation by Bacteria Compartmentalized within Microemulsion Droplets
Amphiphilic
inducer molecules such as <i>N</i>-acyl-l-homoserine
lactones (AHLs) or isopropyl-β-d-thio-galactopyranoside
(IPTG) can be utilized for the implementation
of an artificial communication system between groups of <i>E.
coli</i> bacteria encapsulated within water-in-oil microemulsion
droplets. Using spatially extended arrays of microdroplets, we study
the diffusion of both AHL and IPTG from inducer-filled reservoirs
into bacteria-containing droplets, and also from droplets with AHL
producing sender bacteria into neighboring droplets containing receiver
cells. Computational modeling of gene expression dynamics within the
droplets suggests a strongly reduced effective diffusion coefficient
of the inducers, which markedly affects the spatial communication
pattern in the neighborhood of the senders. Engineered bacteria that
integrate AHL and IPTG signals with a synthetic AND gate gene circuit
are shown to respond only in the presence of both types of sender
droplets, which demonstrates the potential of the system for genetically
programmed pattern formation and distributed computing