The process of morphogenesis carefully crafts cells into complex organ structures which allows them to perform their unique functions. During brain development, the neuroepithelial tissue must go through apical and basal folding which is mediated through the instruction of both intrinsic and extrinsic factors. While much is known about apical folding, the mechanisms that regulate basal folding are less understood.
View Article and Find Full Text PDFEarly development depends on a pool of maternal factors incorporated into the mature oocyte during oogenesis that perform all cellular functions necessary for development until zygotic genome activation. Typically, genetic targeting of these maternal factors requires an additional generation to identify maternal-effect phenotypes, hindering the ability to determine the role of maternally-expressed genes during development. The discovery of the biallelic editing capabilities of CRISPR-Cas9 has allowed screening of embryonic phenotypes in somatic tissues of injected embryos or "crispants," augmenting the understanding of the role zygotically-expressed genes play in developmental programs.
View Article and Find Full Text PDFIn animals, early development is dependent on a pool of maternal factors, both RNA and proteins, which are required for basic cellular processes and cell differentiation until zygotic genome activation. The role of the majority of these maternally expressed factors is not fully understood. By exploiting the biallelic editing ability of CRISPR-Cas9, we identify and characterize maternal-effect genes in a single generation, using a maternal crispant technique.
View Article and Find Full Text PDFBackground: The effect of different musical styles on serum cortisol levels, blood pressure, and heart rate is currently unknown.
Methods: 60 subjects were randomly assigned to three groups that listened to various compositions by W. A.
Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds--a departure from the 'hot mode' accretion model--although unambiguous observational support for this prediction remains elusive.
View Article and Find Full Text PDFThe Universe's largest galaxies reside at the centres of galaxy clusters and are embedded in hot gas that, if left undisturbed, would cool quickly and create many more new stars than are actually observed. Cooling can be regulated by feedback from accretion of cooling gas onto the central black hole, but requires an accretion rate finely tuned to the thermodynamic state of the hot gas. Theoretical models in which cold clouds precipitate out of the hot gas via thermal instability and accrete onto the black hole exhibit the necessary tuning.
View Article and Find Full Text PDFThe neutral κ(2)N,O-salicylaldiminato Ni(II) complexes [κ(2)N,O-{(2,6-(3',5'-R2C6H3)2C6H3-N═C(H)-(3,5-I2-2-O-C6H2)}]NiCH3(pyridine)] (1a-pyr, R = Me; 1b-pyr, R = Et; 1c-pyr, R = iPr) convert ethylene to hyperbranched low-molecular-weight oligomers (Mn ca. 1000 g mol(-1)) with high productivities. While all three catalysts are capable of generating hyperbranched structures, branching densities decrease significantly with the nature of the remote substituent along Me > Et > iPr and oligomer molecular weights increase.
View Article and Find Full Text PDFClusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of a cluster, and the baryons confined by this potential radiate X-rays with a luminosity that depends mainly on the gas density in the cluster's core. Predictions of the X-rays' properties based on models of cluster formation do not, however, agree with the observations.
View Article and Find Full Text PDFCosmological simulations predict that a large fraction of the baryonic mass of the universe exists as 105-107 K diffuse, X-ray-emitting gas, tracing low-density filament and sheetlike structures exterior to massive clusters of galaxies. If present, this gas helps reconcile the current shortfall in observed baryon counts relative to the predictions of the standard big bang model. We present here the discovery and analysis of a 5 sigma significance half-degree filamentary structure, which is present in both the I-band galaxy surface density and the unresolved X-ray emission in a deep ROSAT PSPC field.
View Article and Find Full Text PDFWe used a saline load test in 50 consecutive patients with periarticular lacerations suggestive of joint penetration. The surgeon had predicted on clinical grounds whether or not the laceration penetrated the joint. Joint penetration was demonstrated in 14 and was absent in 36.
View Article and Find Full Text PDFWe report a nondisplaced femoral neck and head fracture diagnosed acutely by CT scanning. This case illustrates the potential benefits of an acute femoral neck/head CT scan in obtunded polytrauma patients with high-energy femoral shaft fractures.
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