4,247 research outputs found
Familial Sneddon's syndrome
A syndrome associating Livedo Reticularis (LR) with Cerebrovascular disease (CVD) was described, in 1965, by Sneddon. It occurs sporadically, but a few familial cases of Sneddon's Syndrome (SS) have been reported, like these 3 cases that represent one of the largest number among siblings. We studied three male brothers, aged 28, 37 and 42 years, with CVD (ischaemic stroke in 2 patients and cerebral haemorrhages in the third) and their sister with no CVD. All patients presented with long lasting Livedo Reticularis, extending beyond the lower limbs. Skin biopsy on the centre of the reticular pattern showed, only in the second patient, partial endothelium detachment in dermo-hypodermic blood vessels. The males also had accesses of Livedoid Vasculitis (LV), in which a skin biopsy showed obliteration of several upper dermal vessels with hialin thrombi and a very scarce inflammatory infiltrate. Complementary studies, with an extensive investigation on pro-coagulation/pro-thrombotic features including antiphospholipid antibodies, were repeatedly negative. Their non-consanguineous parents were not affected, but among these kindred of 9 individuals, apart from the 4 patients reported above, LR and LV were present in two other brothers and also in an aunt and uncle, suggesting autosomal dominant pattern of inheritance, with incomplete penetrance. The relationship between Sneddon's Syndrome and Antiphospholipid Antibody Syndrome is controversial. The present cases, having repeatedly negative antiphospholipid antibodies, support the classification of Sneddon's Syndrome as an independent nosological entity
Influence of aerial seed banks on germination response in three desert plant species
© The Author 2016. Aims To determine if the germination response of desert plant species to a period of aerial storage in field conditions (i.e. mature seeds that remain attached to the parent plant) is comparable to seeds harvested at maturity and stored in ambient laboratory conditions, to better understand the role of aerial seed bank in the germination ecology of desert plants, using one annual and two perennial species. Methods Seeds of three desert plants (Anastatica hierochuntica, Blepharis ciliaris and Scrophularia deserti) that matured in June 2014, were collected from wild plants in June and November 2014, and germinated under two photoperiods (0, 12 hours light) and three thermoperiods (night/day temperatures of 15/25, 20/30 and 25/35°C). Important Findings Seeds of B. ciliaris and S. deserti had significantly higher germination percentages when harvested and stored for five months, compared to being stored in the aerial seed bank. Germination percentages of these two species increased with decreasing temperature and in the presence of light. These results indicate that these species use a combination of aerial and soil seed banks to maintain a percentage of viable seeds through favourable germination periods. Germination percentages of A. hierochuntica were high under all tested circumstances, indicating that this species relies mainly on the aerial seed bank to maintain a percentage of viable seeds through favourable germination periods. This study shows that the population survival strategies of an aerial seed bank are species-specific. These results have practical implications for conservation and habitat restoration for these species, and also for their propagation since early collection of mature fruits and ex situ storage will result in greater germination percentages of some species
Charge Measurement of Cosmic Ray Nuclei with the Plastic Scintillator Detector of DAMPE
One of the main purposes of the DArk Matter Particle Explorer (DAMPE) is to
measure the cosmic ray nuclei up to several tens of TeV or beyond, whose origin
and propagation remains a hot topic in astrophysics. The Plastic Scintillator
Detector (PSD) on top of DAMPE is designed to measure the charges of cosmic ray
nuclei from H to Fe and serves as a veto detector for discriminating gamma-rays
from charged particles. We propose in this paper a charge reconstruction
procedure to optimize the PSD performance in charge measurement. Essentials of
our approach, including track finding, alignment of PSD, light attenuation
correction, quenching and equalization correction are described detailedly in
this paper after a brief description of the structure and operational principle
of the PSD. Our results show that the PSD works very well and almost all the
elements in cosmic rays from H to Fe are clearly identified in the charge
spectrum.Comment: 20 pages, 4 figure
Nasal cannula use during polysomnography in children aged under three with suspected sleep apnea
Nasal cannula; Pediatric sleep apnea; PolysomnographyCánula nasal; Apnea del sueño pediátrica; PolisomnografÃaCà nula nasal; Apnea del son pedià trica; PolisomnografiaObjective
Early diagnosis of obstructive sleep apnea (OSA) in children is important. The use of a nasal cannula as an airflow sensor during polysomnography has not been evaluated in younger children. The study aims to evaluate the use of nasal cannula in detecting respiratory events in children under three with suspected OSA during daytime nap studies.
Methods
A total of 185 patients were prospectively included. Respiratory events were scored using nasal cannula alone, thermistor alone, and both methods simultaneously as the airflow sensor. Agreement and diagnostic accuracy were assessed.
Results
One hundred and seventy-two children were finally analyzed and 110 (64.0%) presented OSA. Total sleep time with an uninterpretable signal was longer with the nasal cannula than with the thermistor (17.8% vs 1.9%; p < 0.001), and was associated with poor sensor tolerance and adenotonsillar hypertrophy. In the estimation of the apnea-hypopnea index, the nasal cannula showed lower agreement than the thermistor with the joint use of the two sensors (intraclass correlation coefficient: 0.79 vs 0.996 with thermistor). Compared with the thermistor, the nasal cannula presented lower sensitivity for detecting OSA (82.7% vs 95.5%) and a lower negative predictive value (76.5% vs 92.4%). Overall, fewer children were diagnosed with severe OSA with the nasal cannula (19.8% vs 30.8% with the thermistor, and 32.6% with both).
Conclusions
In children under the age of three, the ability of the nasal cannula to detect obstructive events was relatively low. Therefore, other non-invasive measurements for identifying respiratory events during sleep may be of additional value
End-tidal and transcutaneous CO2 monitoring during sleep in children aged under three with suspected sleep apnea
Monitorización transcutánea de CO2; Niños; Apnea del sueñoTranscutaneous CO2 monitoring; Children; Sleep apneaMonitorització transcutà nia de CO2; Nens; Apnea del so
Correction Method for the Readout Saturation of the DAMPE Calorimeter
The DArk Matter Particle Explorer (DAMPE) is a space-borne high energy
cosmic-ray and -ray detector which operates smoothly since the launch
on December 17, 2015. The bismuth germanium oxide (BGO) calorimeter is one of
the key sub-detectors of DAMPE used for energy measurement and electron proton
identification. For events with total energy deposit higher than decades of
TeV, the readouts of PMTs coupled on the BGO crystals would become saturated,
which results in an underestimation of the energy measurement. Based on
detailed simulations, we develop a correction method for the saturation effect
according to the shower development topologies and energies measured by
neighbouring BGO crystals. The verification with simulated and on-orbit events
shows that this method can well reconstruct the energy deposit in the saturated
BGO crystal.Comment: 17 pages, 9 figures, to be published in Nuclear Inst. and Methods in
Physics Research,
Characterizing the community structure of complex networks
Community structure is one of the key properties of complex networks and
plays a crucial role in their topology and function. While an impressive amount
of work has been done on the issue of community detection, very little
attention has been so far devoted to the investigation of communities in real
networks. We present a systematic empirical analysis of the statistical
properties of communities in large information, communication, technological,
biological, and social networks. We find that the mesoscopic organization of
networks of the same category is remarkably similar. This is reflected in
several characteristics of community structure, which can be used as
``fingerprints'' of specific network categories. While community size
distributions are always broad, certain categories of networks consist mainly
of tree-like communities, while others have denser modules. Average path
lengths within communities initially grow logarithmically with community size,
but the growth saturates or slows down for communities larger than a
characteristic size. This behaviour is related to the presence of hubs within
communities, whose roles differ across categories. Also the community
embeddedness of nodes, measured in terms of the fraction of links within their
communities, has a characteristic distribution for each category. Our findings
are verified by the use of two fundamentally different community detection
methods.Comment: 15 pages, 20 figures, 4 table
Habitat fragmentation and the future structure of tree assemblages in a fragmented Atlantic forest landscape
The biodiversity value of human-modified landscapes has become a central question in the tropical forest conservation biology, yet the degree to which plant populations and communities are restructured in response to environmental change remains unclear. Here, we address tree species density in a fragmented Atlantic forest landscape to test the hypothesis that tree assemblages inhabiting edge-dominated forest habitats approach typical conditions of early successional systems. Seedlings and adults from 141 tree species were sampled across 39 0.1-ha plots: 19 in small fragments (55 % of all tree species exhibiting higher densities in small fragments than in mature forest, particularly pioneers (>60 % of all species). Seedlings and adults of these proliferating species differed from species exhibiting population declines in terms of wood density and seed size, respectively. Additionally, pioneers were more abundant than shade-tolerant species, as were hardwood species in the case of seedlings. Tree species showing highest population increases consisted largely of long-lived, light-demanding canopy species bearing soft or hardwood and small-to-medium-sized seeds. Tree assemblage structure also differed in terms of forest habitats with small forest fragments supporting few rare species, whereas the most rapidly proliferating species were much more widespread and abundant in fragments. However, 60 % of all adult pioneer species recorded in small fragments were not recorded as seedlings in this habitat type, although both seedling and adult assemblages were dominated by pioneer species. Edge-dominated tree assemblages are likely to experience long-term shifts toward greater dominance of long-lived, pioneer canopy species
Downregulation of Mcl-1 has anti-inflammatory pro-resolution effects and enhances bacterial clearance from the lung
Phagocytes not only coordinate acute inflammation and host defense at mucosal sites, but also contribute to tissue damage. Respiratory infection causes a globally significant disease burden and frequently progresses to acute respiratory distress syndrome, a devastating inflammatory condition characterized by neutrophil recruitment and accumulation of protein-rich edema fluid causing impaired lung function. We hypothesized that targeting the intracellular protein myeloid cell leukemia 1 (Mcl-1) by a cyclin-dependent kinase inhibitor (AT7519) or a flavone (wogonin) would accelerate neutrophil apoptosis and resolution of established inflammation, but without detriment to bacterial clearance. Mcl-1 loss induced human neutrophil apoptosis, but did not induce macrophage apoptosis nor impair phagocytosis of apoptotic neutrophils. Neutrophil-dominant inflammation was modelled in mice by either endotoxin or bacteria (Escherichia coli). Downregulating inflammatory cell Mcl-1 had anti-inflammatory, pro-resolution effects, shortening the resolution interval (R(i)) from 19 to 7 h and improved organ dysfunction with enhanced alveolar–capillary barrier integrity. Conversely, attenuating drug-induced Mcl-1 downregulation inhibited neutrophil apoptosis and delayed resolution of endotoxin-mediated lung inflammation. Importantly, manipulating lung inflammatory cell Mcl-1 also accelerated resolution of bacterial infection (R(i); 50 to 16 h) concurrent with enhanced bacterial clearance. Therefore, manipulating inflammatory cell Mcl-1 accelerates inflammation resolution without detriment to host defense against bacteria, and represents a target for treating infection-associated inflammation
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