6,509 research outputs found
Editorial: Neuroglial antibodies: From clinical associations to pathophysiological investigations
Negative plant–soil feedback predicts tree-species relative abundance in a tropical forest
The accumulation of species-specific enemies around adults is hypothesized to maintain plant diversity by limiting the recruitment of conspecific seedlings relative to heterospecific seedlings1,2,3,4,5,6. Although previous studies in forested ecosystems have documented patterns consistent with the process of negative feedback7,8,9,10,11,12,13,14,15,16, these studies are unable to address which classes of enemies (for example, pathogens, invertebrates, mammals) exhibit species-specific effects strong enough to generate negative feedback17, and whether negative feedback at the level of the individual tree is sufficient to influence community-wide forest composition. Here we use fully reciprocal shade-house and field experiments to test whether the performance of conspecific tree seedlings (relative to heterospecific seedlings) is reduced when grown in the presence of enemies associated with adult trees. Both experiments provide strong evidence for negative plant–soil feedback mediated by soil biota. In contrast, above-ground enemies (mammals, foliar herbivores and foliar pathogens) contributed little to negative feedback observed in the field. In both experiments, we found that tree species that showed stronger negative feedback were less common as adults in the forest community, indicating that susceptibility to soil biota may determine species relative abundance in these tropical forests. Finally, our simulation models confirm that the strength of local negative feedback that we measured is sufficient to produce the observed community-wide patterns in tree-species relative abundance. Our findings indicate that plant–soil feedback is an important mechanism that can maintain species diversity and explain patterns of tree-species relative abundance in tropical forests
Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation
FUNDING AND DISCLOSURE The research was funded by Wellcome Trust (WT098012) to LKH; and National Institute of Health (DK056731) and the Marilyn H. Vincent Foundation to MGM. The University of Michigan Transgenic Core facility is partially supported by the NIH-funded University of Michigan Center for Gastrointestinal Research (DK034933). The remaining authors declare no conflict of interest. ACKNOWLEDGMENTS We thank Dr Celine Cansell, Ms Raffaella Chianese and the staff of the Medical Research Facility for technical assistance. We thank Dr Vladimir Orduña for the scientific advice and technical assistance.Peer reviewedPublisher PD
Towards improving early diagnosis of congenital Chagas disease in an endemic setting.
: Congenital Trypanosoma cruzi transmission is now estimated to account for 22% of new infections, representing a significant public health problem across Latin America and internationally. Treatment during infancy is highly efficacious and well tolerated, but current assays for early detection fail to detect >50% of infected neonates and 9 month follow-up is low. : Women presenting for delivery in two urban hospitals in Santa Cruz department, Bolivia were screened by rapid test. Specimens from infants of infected women were tested by microscopy (micromethod), quantitative PCR (qPCR) and IgM trypomastigote excreted-secreted antigen (TESA)-blots at birth and 1 month, and by IgG serology at 6 and 9 months. : Among 487 infants of 476 seropositive women, congenital T. cruzi infection was detected in 38 infants of 35 mothers (7.8%). In cord blood, qPCR, TESA-blot and micromethod sensitivities/specificities were 68.6%/99.1%, 58.3%/99.1% and 16.7%/100%, respectively. When birth and 1 month results were combined, cumulative sensitivities reached 84.2%, 73.7% and 34.2%, respectively. Low birth weight and/or respiratory distress were reported in 11 (29%) infected infants. Infants with clinical signs had higher parasite loads and were significantly more likely to be detected by micromethod. : The proportion of T. cruzi infected infants with clinical signs has fallen from the 1990s, but symptomatic congenital Chagas disease still represents a significant, albeit increasingly challenging to detect, public health problem. Molecular methods could facilitate earlier diagnosis and circumvent loss to follow-up but remain logistically and economically prohibitive for routine screening in resource-limited settings.<br/
Conformal TiO aerogel-like films by plasma deposition: from omniphobic antireflective coatings to perovskite solar cells photoelectrodes
The ability to control porosity in oxide thin films is one of the key factors
that determine their properties. Despite the abundance of dry processes for the
synthesis of oxide porous layers, the high porosity range is typically achieved
by spin-coating-based wet chemical methods. Besides, special techniques such as
supercritical drying are required to replace the pore liquid with air while
maintaining the porous network. In this study, we propose a new method for the
fabrication of ultra-porous titanium dioxide thin films at room or mild
temperatures (T lower or equal to 120 degrees Celsius) by the sequential
process involving plasma deposition and etching. These films are conformal to
the substrate topography even for high-aspect-ratio substrates and show
percolated porosity values above 85 percent that are comparable to advanced
aerogels. The films deposited at room temperature are amorphous. However, they
become partly crystalline at slightly higher temperatures presenting a
distribution of anatase clusters embedded in the sponge-like structure.
Surprisingly, the porous structure remains after annealing the films at 450
degrees Celsius in air, which increases the fraction of the embedded anatase
nanocrystals. The films are antireflective, omniphobic, and photoactive
becoming super-hydrophilic subjected to UV light irradiation The supported
percolated nanoporous structure can be used as an electron-conducting electrode
in perovskite solar cells. The properties of the cells depend on the aerogel
film thickness reaching efficiencies close to those of commercial mesoporous
anatase electrodes. This generic solvent-free synthesis is scalable and is
applicable to ultra-high porous conformal oxides of different compositions with
potential applications in photonics, optoelectronics, energy storage, and
controlled wetting.Comment: 31 pages, 10 Figs. plus Supporting Information 7 pags, 6 figs. Full
Pape
Kinetic modelling of competition and depletion of shared miRNAs by competing endogenous RNAs
Non-conding RNAs play a key role in the post-transcriptional regulation of
mRNA translation and turnover in eukaryotes. miRNAs, in particular, interact
with their target RNAs through protein-mediated, sequence-specific binding,
giving rise to extended and highly heterogeneous miRNA-RNA interaction
networks. Within such networks, competition to bind miRNAs can generate an
effective positive coupling between their targets. Competing endogenous RNAs
(ceRNAs) can in turn regulate each other through miRNA-mediated crosstalk.
Albeit potentially weak, ceRNA interactions can occur both dynamically,
affecting e.g. the regulatory clock, and at stationarity, in which case ceRNA
networks as a whole can be implicated in the composition of the cell's
proteome. Many features of ceRNA interactions, including the conditions under
which they become significant, can be unraveled by mathematical and in silico
models. We review the understanding of the ceRNA effect obtained within such
frameworks, focusing on the methods employed to quantify it, its role in the
processing of gene expression noise, and how network topology can determine its
reach.Comment: review article, 29 pages, 7 figure
MicroRNAs in cardiac arrhythmia: DNA sequence variation of MiR-1 and MiR-133A in long QT syndrome.
Long QT syndrome (LQTS) is a genetic cardiac condition associated with prolonged ventricular repolarization, primarily a result of perturbations in cardiac ion channels, which predisposes individuals to life-threatening arrhythmias. Using DNA screening and sequencing methods, over 700 different LQTS-causing mutations have been identified in 13 genes worldwide. Despite this, the genetic cause of 30-50% of LQTS is presently unknown. MicroRNAs (miRNAs) are small (∼ 22 nucleotides) noncoding RNAs which post-transcriptionally regulate gene expression by binding complementary sequences within messenger RNAs (mRNAs). The human genome encodes over 1800 miRNAs, which target about 60% of human genes. Consequently, miRNAs are likely to regulate many complex processes in the body, indeed aberrant expression of various miRNA species has been implicated in numerous disease states, including cardiovascular diseases. MiR-1 and MiR-133A are the most abundant miRNAs in the heart and have both been reported to regulate cardiac ion channels. We hypothesized that, as a consequence of their role in regulating cardiac ion channels, genetic variation in the genes which encode MiR-1 and MiR-133A might explain some cases of LQTS. Four miRNA genes (miR-1-1, miR-1-2, miR-133a-1 and miR-133a-2), which encode MiR-1 and MiR-133A, were sequenced in 125 LQTS probands. No genetic variants were identified in miR-1-1 or miR-133a-1; but in miR-1-2 we identified a single substitution (n.100A> G) and in miR-133a-2 we identified two substitutions (n.-19G> A and n.98C> T). None of the variants affect the mature miRNA products. Our findings indicate that sequence variants of miR-1-1, miR-1-2, miR-133a-1 and miR-133a-2 are not a cause of LQTS in this cohort
Measurement of Total and Differential Cross Sections of Neutrino and Antineutrino Coherent Production on Carbon
Neutrino induced coherent charged pion production on nuclei,
, is a rare inelastic interaction in
which the four-momentum squared transfered to the nucleus is nearly zero,
leaving it intact. We identify such events in the scintillator of MINERvA by
reconstructing |t| from the final state pion and muon momenta and by removing
events with evidence of energetic nuclear recoil or production of other final
state particles. We measure the total neutrino and antineutrino cross sections
as a function of neutrino energy between 2 and 20 GeV and measure flux
integrated differential cross sections as a function of , and
. The dependence and equality of the neutrino and
anti-neutrino cross-sections at finite provide a confirmation of Adler's
PCAC hypothesis
Measurement of the muon anti-neutrino double-differential cross section for quasi-elastic scattering on hydrocarbon at~ GeV
We present double-differential measurements of anti-neutrino quasi-elastic
scattering in the MINERvA detector. This study improves on a previous single
differential measurement by using updated reconstruction algorithms and
interaction models, and provides a complete description of observed muon
kinematics in the form of a double-differential cross section with respect to
muon transverse and longitudinal momentum. We include in our signal definition
zero-meson final states arising from multi-nucleon interactions and from
resonant pion production followed by pion absorption in the primary nucleus. We
find that model agreement is considerably improved by a model tuned to MINERvA
inclusive neutrino scattering data that incorporates nuclear effects such as
weak nuclear screening and two-particle, two-hole enhancements.Comment: 47 pages, 31 figure
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