43 research outputs found
Hyperserotonemia in Adults with Autistic Disorder
Abstract Hyperserotonemia is the most consistent serotonin-related finding in autism. The basis of this phenomenon, and its relationship to the central serotonergic dysfunction remains unclear. Platelet serotonin level (PSL) in 53 autistic adults and 45 healthy controls was measured. Mean PSL in autistic group (75.7 ± 37.4 ng/lL) was significantly higher than the control sample (59.2 ± 16.2 ng/lL) due to a presence of hyperserotonemic subjects which comprised 32% of the patients. PSL of autistic subjects did not correlate with the severity of symptoms, as measured by total CARS score, or the degree of mental retardation. However, significant negative relationship was observed between PSL and speech development, indicating the relationship between the peripheral 5HT concentrations and verbal abilities in autistic subjects
Synchronization in complex networks
Synchronization processes in populations of locally interacting elements are
in the focus of intense research in physical, biological, chemical,
technological and social systems. The many efforts devoted to understand
synchronization phenomena in natural systems take now advantage of the recent
theory of complex networks. In this review, we report the advances in the
comprehension of synchronization phenomena when oscillating elements are
constrained to interact in a complex network topology. We also overview the new
emergent features coming out from the interplay between the structure and the
function of the underlying pattern of connections. Extensive numerical work as
well as analytical approaches to the problem are presented. Finally, we review
several applications of synchronization in complex networks to different
disciplines: biological systems and neuroscience, engineering and computer
science, and economy and social sciences.Comment: Final version published in Physics Reports. More information
available at http://synchronets.googlepages.com
Evolutionary Analysis of DELLA-Associated Transcriptional Networks
[EN] DELLA proteins are transcriptional regulators present in all land plants which have been shown to modulate the activity of over 100 transcription factors in Arabidopsis, involved in multiple physiological and developmental processes. It has been proposed that DELLAs transduce environmental information to pre-wired transcriptional circuits because their stability is regulated by gibberellins (GAs), whose homeostasis largely depends on environmental signals. The ability of GAs to promote DELLA degradation coincides with the origin of vascular plants, but the presence of DELLAs in other land plants poses at least two questions: what regulatory properties have DELLAs provided to the behavior of transcriptional networks in land plants, and how has the recruitment of DELLAs by GA signaling affected this regulation. To address these issues, we have constructed gene co-expression networks of four different organisms within the green lineage with different properties regarding DELLAs: Arabidopsis thaliana and Solanum lycopersicum (both with GA- regulated DELLA proteins), Physcomitrella patens (with GA- independent DELLA proteins) and Chlamydomonas reinhardtii (a green alga without DELLA), and we have examined the relative evolution of the subnetworks containing the potential DELLA-dependent transcriptomes. Network analysis indicates a relative increase in parameters associated with the degree of interconnectivity in the DELLA-associated subnetworks of land plants, with a stronger effect in species with GA- regulated DELLA proteins. These results suggest that DELLAs may have played a role in the coordination of multiple transcriptional programs along evolution, and the function of DELLAs as regulatory 'hubs' became further consolidated after their recruitment by GA signaling in higher plants.Work in the laboratories was funded by grants BFU2016-80621-P and BIO2014-52425-P of the Spanish Ministry of Economy, Industry and Competitiveness, and H2020-MSCA-RISE-2014-644435 of the European Union. AB-M and JH-G hold Fellowships of the Spanish Ministry of Education, Culture and Sport FPU14/01941 and FPU15/01756, respectively.Briones-Moreno, A.; HernĂĄndez-GarcĂa, J.; Vargas-ChĂĄvez, C.; Romero-Campero FJ; Romero, J.; Valverde, F.; Blazquez Rodriguez, MA. (2017). Evolutionary Analysis of DELLA-Associated Transcriptional Networks. Frontiers in Plant Science. 8(626):1-11. https://doi.org/10.3389/fpls.2017.00626S111862
Excimer formation by steric twisting in carbazole and triphenylamine-based host materials
This paper presents a detailed spectroscopic investigation of luminescence properties of 4,4âČ-Bis(N-carbazolyl)-1,1âČ-biphenyl (CBP) and N,N,Nâ,Nâ-tetraphenylbenzidine (TAD) in solutions and neat films. These compounds are compared to their derivatives CDBP and TDAD that contain methyl groups in the 2 and 2â position of the biphenyl core. We find that whereas steric twisting in CDBP and TDAD leads to a high triplet energy of about 3.0 and 3.1 eV, respectively, these compounds also tend to form triplet excimers in a neat film, in contrast to CBP and TAD. By comparison with N-phenylcarbazole (NPC) and triphenylamine (TPA), on which these compounds are based, as well as with the rigid spiro analogs to CBP and TAD we show that the reduced excimer formation in CBP and TAD can be attributed to a localization of the excitation onto the central biphenyl part of the molecule.We acknowledge support from the Federal Ministry of Education and Research (BMBF) through the project âTrip-Qâ, the German Science Foundation (DFG) through the Research and Training Group GRK 1640 and the UK Engineering and Physical Sciences Research Council (grant number EP/G060738/1).This is the final published version. It first appeared at http://pubs.acs.org/doi/abs/10.1021/jp512772j
Community landscapes: an integrative approach to determine overlapping network module hierarchy, identify key nodes and predict network dynamics
Background: Network communities help the functional organization and
evolution of complex networks. However, the development of a method, which is
both fast and accurate, provides modular overlaps and partitions of a
heterogeneous network, has proven to be rather difficult. Methodology/Principal
Findings: Here we introduce the novel concept of ModuLand, an integrative
method family determining overlapping network modules as hills of an influence
function-based, centrality-type community landscape, and including several
widely used modularization methods as special cases. As various adaptations of
the method family, we developed several algorithms, which provide an efficient
analysis of weighted and directed networks, and (1) determine pervasively
overlapping modules with high resolution; (2) uncover a detailed hierarchical
network structure allowing an efficient, zoom-in analysis of large networks;
(3) allow the determination of key network nodes and (4) help to predict
network dynamics. Conclusions/Significance: The concept opens a wide range of
possibilities to develop new approaches and applications including network
routing, classification, comparison and prediction.Comment: 25 pages with 6 figures and a Glossary + Supporting Information
containing pseudo-codes of all algorithms used, 14 Figures, 5 Tables (with 18
module definitions, 129 different modularization methods, 13 module
comparision methods) and 396 references. All algorithms can be downloaded
from this web-site: http://www.linkgroup.hu/modules.ph
Frenkel exciton model of excitation and recombination processes in crystalline alpha-PTCDA
Fuer anorganische Kristalle werden die chemischen Bindungen durch kovalente oder ionische
Beitraege dominiert. Im Gegensatz dazu stehen organische Molekuelkristalle, in denen in
jedem der Molekuele starke kovalente Bindungen vorherrschen, waehrend die Molekuele
untereinander nur relativ schwache Wechselwirkung zeigen. Daher sind die Veraenderungen
zwischen den Spektren freier Molekuele und den entsprechenden Kristallen wesentlich
geringer als die zwischen einem freien Atom und einem anorganischen Kristall.
In einem organischen Kristall kann eine optisch erzeugte elektronische Anregung zwischen
verschiedenen Molekuelen transferiert werden. Fuer das Modellsystem PTCDA
(3,4,9,10-Perylentetracarbonsaeuredianhydrid) wurden die elektronischen und vibronischen
Spektren analysiert und die aus dem Transfer der Anregung resultierende exzitonische
Bandstruktur untersucht. Die optische Absorption erzeugt ein Frenkel-Exziton am
Dispersionsmaximum in der Naehe des Gamma-Punktes in der Brillouin-Zone. Durch
inelastische Streuvorgaenge relaxiert dieses Exziton zum Dispersionsminimum am Rand
der Brillouin-Zone. Die Photolumineszenz bei tiefen Temperaturen entsteht daraus durch
vertikale Rekombination, wobei der Endzustand eine vibronische Anregung mit endlichem
Quasi-Impuls enthaelt. Die berechnete strahlende Rekombinationsrate und die Linienform
der Photolumineszenzbande stimmen dabei gut mit den experimentellen Ergebnissen ueberein.
Das Modell des Exzitonentransfers im Volumenmaterial kann auf Filme
endlicher Dicke verallgemeinert werden, so dass sich die
veraenderten optischen Eigenschaften duenner Filme beschreiben
lassen. Durch die endliche Zahl der molekularen Monolagen in einem
solchen Film ist das energetische Spektrum diskret, wobei die
Einhuellenden der exzitonischen Wellenfunktionen entlang der
Quantisierungsrichtung an die Zustaende in einem Quantentrog mit
unendlich hohen Barrieren erinnern.
Das Zusammenspiel von geometrischer Randbedingung und energetischer
Lage des molekularen uebergangs in der Randschicht kann sowohl
zu einer Rot- als auch zu einer Blauverschiebung der optischen Antwort
fuehren
Frenkel exciton model of excitation and recombination processes in crystalline alpha-PTCDA
Fuer anorganische Kristalle werden die chemischen Bindungen durch kovalente oder ionische
Beitraege dominiert. Im Gegensatz dazu stehen organische Molekuelkristalle, in denen in
jedem der Molekuele starke kovalente Bindungen vorherrschen, waehrend die Molekuele
untereinander nur relativ schwache Wechselwirkung zeigen. Daher sind die Veraenderungen
zwischen den Spektren freier Molekuele und den entsprechenden Kristallen wesentlich
geringer als die zwischen einem freien Atom und einem anorganischen Kristall.
In einem organischen Kristall kann eine optisch erzeugte elektronische Anregung zwischen
verschiedenen Molekuelen transferiert werden. Fuer das Modellsystem PTCDA
(3,4,9,10-Perylentetracarbonsaeuredianhydrid) wurden die elektronischen und vibronischen
Spektren analysiert und die aus dem Transfer der Anregung resultierende exzitonische
Bandstruktur untersucht. Die optische Absorption erzeugt ein Frenkel-Exziton am
Dispersionsmaximum in der Naehe des Gamma-Punktes in der Brillouin-Zone. Durch
inelastische Streuvorgaenge relaxiert dieses Exziton zum Dispersionsminimum am Rand
der Brillouin-Zone. Die Photolumineszenz bei tiefen Temperaturen entsteht daraus durch
vertikale Rekombination, wobei der Endzustand eine vibronische Anregung mit endlichem
Quasi-Impuls enthaelt. Die berechnete strahlende Rekombinationsrate und die Linienform
der Photolumineszenzbande stimmen dabei gut mit den experimentellen Ergebnissen ueberein.
Das Modell des Exzitonentransfers im Volumenmaterial kann auf Filme
endlicher Dicke verallgemeinert werden, so dass sich die
veraenderten optischen Eigenschaften duenner Filme beschreiben
lassen. Durch die endliche Zahl der molekularen Monolagen in einem
solchen Film ist das energetische Spektrum diskret, wobei die
Einhuellenden der exzitonischen Wellenfunktionen entlang der
Quantisierungsrichtung an die Zustaende in einem Quantentrog mit
unendlich hohen Barrieren erinnern.
Das Zusammenspiel von geometrischer Randbedingung und energetischer
Lage des molekularen uebergangs in der Randschicht kann sowohl
zu einer Rot- als auch zu einer Blauverschiebung der optischen Antwort
fuehren
Efficiency of informational transfer in regular and complex networks
We analyze the process of informational exchange through complex networks by measuring network efficiencies. Aiming to study nonclustered systems, we propose a modification of this measure on the local level. We apply this method to an extension of the class of small worlds that includes declustered networks and show that they are locally quite efficient, although their clustering coefficient is practically zero. Unweighted systems with small-world and scale-free topologies are shown to be both globally and locally efficient. Our method is also applied to characterize weighted networks. In particular we examine the properties of underground transportation systems of Madrid and Barcelona and reinterpret the results obtained for the Boston subway network