6,582 research outputs found
Human occipital and parietal GABA selectively influence visual perception of orientation and size
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in human brain. GABA level varies substantially across individuals and this variability is associated with inter-individual differences in visual perception. However, it remains unclear whether the association between GABA level and visual perception reflects a general influence of visual inhibition, or whether GABA level of different cortical regions selectively influences perception of different visual features. To address this, we studied how GABA level in parietal and occipital cortices related to inter-individual differences in size, orientation, and brightness perception, in a group of healthy young male participants. We used visual contextual illusion as a perceptual assay, since it dissociates perceptual content from stimulus content and its magnitude reflects the effect of visual inhibition. Across individuals, we observed selective correlations between GABA level and the magnitude of contextual illusion. Specifically, parietal GABA level correlated with size illusion magnitude but not with orientation or brightness illusion magnitude; in contrast, occipital GABA level correlated with orientation illusion magnitude but not with size or brightness illusion magnitude. Our findings reveal a region- and feature-dependent influence of GABA level on human visual perception. Parietal and occipital cortices contain, respectively, topographic maps of size and orientation preference in which neural responses to sizes or orientations are modualted by intra-regional lateral connections. We propose that these lateral connections may underlie the selective influence of GABA level on visual feature perception.SIGNIFICANCE STATEMENTGamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in human visual system, varies substantially across individuals and this variability is linked to inter-individual differences in many aspects of visual perception. The widespread influence of GABA raises the question of whether inter-individual variability in GABA reflects an overall variability in visual inhibition and has a general influence on visual perception, or whether GABA level of different cortical regions has selective influence on perception of different visual features. Here we report a region- and feature-dependent influence of GABA level on human visual perception. Our findings suggest that GABA level of a cortical region selectively influences perception of visual features that are topographically mapped in this region through intra-regional lateral connections
Mobile Communication Signatures of Unemployment
The mapping of populations socio-economic well-being is highly constrained by
the logistics of censuses and surveys. Consequently, spatially detailed changes
across scales of days, weeks, or months, or even year to year, are difficult to
assess; thus the speed of which policies can be designed and evaluated is
limited. However, recent studies have shown the value of mobile phone data as
an enabling methodology for demographic modeling and measurement. In this work,
we investigate whether indicators extracted from mobile phone usage can reveal
information about the socio-economical status of microregions such as districts
(i.e., average spatial resolution < 2.7km). For this we examine anonymized
mobile phone metadata combined with beneficiaries records from unemployment
benefit program. We find that aggregated activity, social, and mobility
patterns strongly correlate with unemployment. Furthermore, we construct a
simple model to produce accurate reconstruction of district level unemployment
from their mobile communication patterns alone. Our results suggest that
reliable and cost-effective economical indicators could be built based on
passively collected and anonymized mobile phone data. With similar data being
collected every day by telecommunication services across the world,
survey-based methods of measuring community socioeconomic status could
potentially be augmented or replaced by such passive sensing methods in the
future
Effect modifications of smoking on risk of mortality associated with influenza
BACKGROUND AND AIMS: Influenza is well known to cause heavy disease burden in both temperate and tropical/subtropical regions. Although smoking has been found to increase susceptibility to influenza infection, its role in modifying the mortality risk associated with influenza remains unexplored. This study examined the effect modifications of cigarette smoking on influenza-associated mortality in a cohort of older …postprin
Digit-only sauropod pes trackways from China - evidence of swimming or a preservational phenomenon?
For more than 70 years unusual sauropod trackways have played a pivotal role in debates about the swimming ability of sauropods. Most claims that sauropods could swim have been based on manus-only or manus-dominated trackways. However none of these incomplete trackways has been entirely convincing, and most have proved to be taphonomic artifacts, either undertracks or the result of differential depth of penetration of manus and pes tracks, but otherwise showed the typical pattern of normal walking trackways. Here we report an assemblage of unusual sauropod tracks from the Lower Cretaceous Hekou Group of Gansu Province, northern China, characterized by the preservation of only the pes claw traces, that we interpret as having been left by walking, not buoyant or swimming, individuals. They are interpreted as the result of animals moving on a soft mud-silt substrate, projecting their claws deeply to register their traces on an underlying sand layer where they gained more grip during progression. Other sauropod walking trackways on the same surface with both pes and manus traces preserved, were probably left earlier on relatively firm substrates that predated the deposition of soft mud and silt . Presently, there is no convincing evidence of swimming sauropods from their trackways, which is not to say that sauropods did not swim at all
Rubber Impact on 3D Textile Composites
A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools
Potential immunomodulatory effects of SCAP on Treg conversion in tissue regeneration for regenerative endodontic treatment
To evaluate the expression of Foxp3‐positive lymphocytes around newly formed tissue after regenerative endodontic treatment (RET) in vivo and investigate the effects of stem cells from the apical papilla (SCAP) on the conversion of CD4+CD25− T cells to CD4+CD25+Foxp3+ regulatory T cells (Tregs) in vitro. Methodology Three 6‐month‐old beagles with nine doubled‐rooted premolars in each dog were randomly assigned to the RET group and the control group. RET was performed after apical periodontitis had been induced in the experimental immature teeth. Three months later, the expression of Foxp3 was detected in the histological sections by immunofluorescent staining. Human SCAP and CD4+CD25− T cells from mice spleens (1 : 1 and 1 : 5) were co‐cultured in cell–cell contact or in Transwells, respectively, for 24 and 72 h in vitro. The percentage of Tregs was evaluated by flow cytometry. The results were analysed using the Fisher's exact test and analysis of variance. P < 0.05 was regarded as statistically significant. Results Inflammatory cells were present with tissue regeneration in the RET group, and Foxp3‐positive T cells were enriched around the newly formed tissues. SCAP promoted Treg conversion after 72 h in vitro. Cell–cell contact played an important role after the 24 h co‐culture, whilst soluble factors were also involved after 72 h (P < 0.05). Conclusions SCAP promoted the conversion of pro‐inflammatory T cells to Tregs in vitro. Tregs were enriched around the regenerating tissues in the root canals after RET, which may create a suitable immune microenvironment for the differentiation of SCAP. This study provides an underlying mechanism for tissue regeneration during RET
Microscopic Polarization in Bilayer Graphene
Bilayer graphene has drawn significant attention due to the opening of a band
gap in its low energy electronic spectrum, which offers a promising route to
electronic applications. The gap can be either tunable through an external
electric field or spontaneously formed through an interaction-induced symmetry
breaking. Our scanning tunneling measurements reveal the microscopic nature of
the bilayer gap to be very different from what is observed in previous
macroscopic measurements or expected from current theoretical models. The
potential difference between the layers, which is proportional to charge
imbalance and determines the gap value, shows strong dependence on the disorder
potential, varying spatially in both magnitude and sign on a microscopic level.
Furthermore, the gap does not vanish at small charge densities. Additional
interaction-induced effects are observed in a magnetic field with the opening
of a subgap when the zero orbital Landau level is placed at the Fermi energy
DSG2 and c-MYC Interact to Regulate the Expression of ADAM17 and Promote the Development of Cervical Cancer
Li-Mian Song,1,* Du-Juan Yao,1,* Lin Xia,1 Xu-Ming Wang,2 Tian Liu,2 Qian-Qian Tang,1 Jun Zhou1 1Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China; 2Department of Pathology, Affiliated Hospital of Guilin Medical College, Guilin, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jun Zhou, Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China, Email [email protected]: To explore the effect of DSG2 on the growth of cervical cancer cells and its possible regulatory mechanism.Methods: The expression levels and survival prognosis of DSG2 and ADAM17 in cervical squamous cell carcinoma tissues and adjacent normal tissues were analyzed by bioinformatics. CCK-8 assay, colony formation assay and Transwell assay were used to detect the effects of DSG2 on the proliferative activity, colony formation ability and migration ability of SiHa and Hela cells. The effect of DSG 2 on the level of ADAM17 transcription and translation was detected by qPCR and Western blot experiments. The interaction between DSG2 and c-MYC was detected by immunocoprecipitation. c-MYC inhibitors were used in HeLa cells overexpressing DSG2 to analyze the effects of DSG2 and c-MYC on proliferation, colony formation and migration of Hela cells, as well as the regulation of ADAM17 expression.Results: DSG2 was highly expressed in cervical squamous cell carcinoma compared with normal tissues (P< 0.05), and high DSG2 expression suggested poor overall survival (P< 0.05). After DSG2 knockdown, the proliferative activity, colony formation and migration ability of SiHa and Hela cells were significantly decreased (P< 0.05). Compared with adjacent normal tissues, ADAM17 was highly expressed in cervical squamous cell carcinoma (P< 0.05), and high ADAM17 expression suggested poor overall survival in cervical cancer patients (P< 0.05). The results of immunocoprecipitation showed the interaction between DSG2 and c-MYC. Compared with DSG2 overexpression group, DSG2 overexpression combined with c-MYC inhibition group significantly decreased cell proliferation, migration and ADAM17 expression (P < 0.05).Conclusion: DSG2 is highly expressed in cervical cancer, and inhibition of DSG2 expression can reduce the proliferation and migration ability of cervical cancer cells, which may be related to the regulation of ADAM17 expression through c-MYC interaction.Keywords: cervical cancer, proliferation, migration, DSG2, c-MYC, ADAM1
Biological diversification linked to environmental stabilization following the Sturtian Snowball glaciation
The body fossil and biomarker records hint at an increase in biotic complexity between the two Cryogenian Snowball Earth episodes (ca. 661 million to ≤650 million years ago). Oxygen and nutrient availability can promote biotic complexity, but nutrient (particularly phosphorus) and redox dynamics across this interval remain poorly understood. Here, we present high-resolution paleoredox and phosphorus phase association data from multiple globally distributed drill core records through the non-glacial interval. These data are first correlated regionally by litho- and chemostratigraphy, and then calibrated within a series of global chronostratigraphic frameworks. The combined data show that regional differences in postglacial redox stabilization were partly controlled by the intensity of phosphorus recycling from marine sediments. The apparent increase in biotic complexity followed a global transition to more stable and less reducing conditions in shallow to mid-depth marine environments and occurred within a tolerable climatic window during progressive cooling after post-Snowball super-greenhouse conditions
Evolution of Th2 responses : Characterization of IL-4/13 in sea bass (Dicentrarchus labrax L.) and studies of expression and biological activity
Acknowledgements This research was funded by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (Grant Agreement 311993 TARGETFISH). T.W. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference number HR09011) and contributing institutions.Peer reviewedPublisher PD
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