1,011 research outputs found
Typical Borel measures on satisfy a multifractal formalism
In this article, we prove that in the Baire category sense, measures
supported by the unit cube of typically satisfy a multifractal
formalism. To achieve this, we compute explicitly the multifractal spectrum of
such typical measures . This spectrum appears to be linear with slope 1,
starting from 0 at exponent 0, ending at dimension at exponent , and it
indeed coincides with the Legendre transform of the -spectrum associated
with typical measures .Comment: 17 pages. To appear in Nonlinearit
First case of highly pathogenic H5N1 avian influenza virus in Spain
<p>Abstract</p> <p>Background</p> <p>The H5N1 strain of avian influenza virus has been involved in severe mortality in domestic poultry, and has also been found in different species of wildlife in Europe. The Basque Country avian influenza surveillance program began sample collection and processing the fall of 2005.</p> <p>Results</p> <p>Here we report the first confirmation of the presence of highly pathogenic H5N1 strain in a Great Crested Grebe (<it>Podiceps cristatus</it>) found dead in a pond near Vitoria in the Basque Country on the North of Spain. Regarding the survey for generic influenza type A virus, we have obtained positive results in about 8% of more that 3500 birds examined.</p> <p>Conclusion</p> <p>We think that the self-limiting nature of our finding and others proves that certain regions have ecological, geographical and climatological features that make it difficult for the H5N1 virus to spread <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> and cause disease at least in the large scale scenario that has been worrying human and animal health authorities during the last years.</p
Leishmanial infection: analysis of its first steps. A review
The first steps in leishmaniasis are critical in determining the evolution of the disease. Major advances have recently been done in understanding this crucial moment. Fundamental research in parasite-vector interaction, parasite biology, insect saliva, and vertebrate host response have shed new light and uncovered a most fascinating and complex moment in leishmaniasis. We review here some of these aspects and we try to connect them in a logical framework
Gamma rays from microquasars Cygnus X-1 and Cygnus X-3
Gamma-ray observations of microquasars at high and very-high energies can
provide valuable information of the acceleration processes inside the jets, the
jet-environment interaction and the disk-jet coupling. Two high-mass
microquasars have been deeply studied to shed light on these aspects: Cygnus
X-1 and Cygnus X-3. Both systems display the canonical hard and soft X-ray
spectral states of black hole transients, where the radiation is dominated by
non-thermal emission from the corona and jets and by thermal emission from the
disk, respectively. Here, we report on the detection of Cygnus X-1 above 60 MeV
using 7.5 yr of Pass8 Fermi-LAT data, correlated with the hard X-ray state. A
hint of orbital flux modulation was also found, as the source is only detected
in phases around the compact object superior conjunction. We conclude that the
high-energy gamma-ray emission from Cygnus X-1 is most likely associated with
jets and its detection allow us to constrain the production site. Moreover, we
include in the discussion the final results of a MAGIC long-term campaign on
Cygnus X-1 that reaches almost 100 hr of observations at different X-ray
states. On the other hand, during summer 2016, Cygnus X-3 underwent a flaring
activity period in radio and high-energy gamma rays, similar to the one that
led to its detection in the high-energy regime in 2009. MAGIC performed
comprehensive follow-up observations for a total of about 70 hr. We discuss our
results in a multi-wavelength context.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC
2017), Bexco, Busan, Korea (arXiv:1708.05153
Arginase levels and their association with Th17-related cytokines, soluble adhesion molecules (sICAM-1 and sVCAM-1) and hemolysis markers among steady-state sickle cell anemia patients
Sickle cell anemia (SCA) is characterized by a marked endothelial dysfunction, owing to many factors. Arginine metabolism can be related to the inflammatory chronic state presented by patients, playing a key role in their clinical outcome and vascular endothelium. We investigated the serum arginase levels in 50 SCA patients (22 men and 28 women, mean age of 17 ± 10.5 years) and 28 healthy controls. Serum arginase levels were associated with biochemical hemolysis markers and cytokines involved in Th17 response, as well as levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1). Arginase concentrations were higher in SCA patients, compared with controls (p = 0.005), and were significantly and positively associated with total bilirubin (p = 0.004), indirect bilirubin (p = 0.04), and aspartate aminotransferase (AST; p = 0.039) in the SCA patient group. Moreover, arginase was significantly and positively associated with transforming growth factor-beta (TGF-beta; p = 0.008) among SCA patients. sICAM-1 was significantly and positively associated to reticulocytes (p = 0.014) and AST (p = 0.04). sVCAM-1 was likewise associated with lactate dehydrogenase (p = 0.03). These data suggest a new insight into arginase metabolism, as we show here a shift in arginine catabolism, where TGF-beta may induces the arginase pathway instead of the nitric oxide pathway and a possible involvement of the vascular activation and the serum arginase in chronic hemolysis among SCA patients. Additional studies should be carried out in order to investigate the mechanisms by which TGF-beta participates in the metabolism of arginase in SCA patients
Fatores de risco para a transmissao vertical do HIV-1 e a influencia da terapia antirretroviral (ARV) no desfecho gestacional
In the absence of intervention, the rate of vertical transmission of HIV can range from 15-45%. With the inclusion of antiretroviral drugs during pregnancy and the choice of delivery route this amounts to less than 2%. However ARV use during pregnancy has generated several questions regarding the adverse effects of the gestational and neonatal outcome. This study aims to analyze the risk factors for vertical transmission of HIV-1 seropositive pregnant women living in Rio Grande and the influence of the use of ARVs in pregnancy outcome. Among the 262 pregnant women studied the rate of vertical transmission of HIV was found to be 3.8%. Regarding the VT, there was a lower risk of transmission when antiretroviral drugs were used and prenatal care was conducted at the referral service. However, the use of ART did not influence the outcome of pregnancy. However, initiation of prenatal care after the first trimester had an influence on low birth weight, as well as performance of less than six visits increased the risk of prematurity. Therefore, the risk factors analyzed in this study appear to be related to the realization of inadequate pre-natal and maternal behavior.Na ausência de intervenção, as taxas de transmissão vertical do HIV podem variar de 15-45%. Com a inserção dos antirretrovirais durante a gestação e a escolha da via de parto estas taxas chegam a menos de 2%. No entanto o uso de ARV na gestação tem gerado várias duvidas quanto aos efeitos adversos causados ao desfecho gestacional e ao neonato. Este estudo objetiva analisar os fatores de risco da transmissão vertical do HIV-1 em gestantes soropositivas atendidas na cidade do Rio Grande e a influência do uso do ARV no desfecho gestacional. Entre as 262 gestantes estudadas a taxa de transmissão vertical do HIV encontrada foi de 3,8%. Em relação à TV, foi observado menor risco de transmissão quando esta havia feito uso de antirretrovirais e o pré-natal era realizado no serviço de referência. Entretanto, o uso de ARV não influenciou negativamente o desfecho gestacional. No entanto, o inicio do pré-natal após o primeiro trimestre teve influencia sobre o baixo peso ao nascer, assim como a realização de menos de seis consultas aumentou o risco de prematuridade. Portanto, os fatores de risco analisados neste estudo parecem estar relacionados à realização não adequada do pré-natal e ao comportamento materno
Reconstructed human pigmented skin/epidermis models achieve epidermal pigmentation through melanocore transfer
Funding: We thank the Electron Microscopy Facility at the Instituto Gulbenkian de Ciência, the Pathological Anatomy service in the Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG) and the Histology Facility at CEDOC for technical assistance. This project was supported by Fundação para a Ciência e a Tecnologia (FCT), Portugal through FCT Unit iNOVA4Health – UIDB/04462/2020 and UIDP/04462/2020, a programme financially supported by FCT / Ministério da Ciência, Tecnologia e Ensino Superior, through national funds, grant PTDC/BIA-CEL/29765/2017, PhD fellowships 2020.08528.BD (SLV), PD/BD/128164/2016, PD/BD/137442/2018 (MVN) and PD/BD/136905/2018 (JC) and the FCT Investigator Program to DCB (IF/00501/2014/CP1252/CT0001).The skin acts as a barrier to environmental insults and provides many vital functions. One of these is to shield DNA from harmful UV radiation, which is achieved by skin pigmentation arising as melanin is produced and dispersed within the epidermal layer. This is a crucial defence against DNA damage, photo-ageing and skin cancer. The mechanisms and regulation of melanogenesis and melanin transfer involve extensive crosstalk between melanocytes and keratinocytes in the epidermis, as well as fibroblasts in the dermal layer. Although the predominant mechanism of melanin transfer continues to be debated and several plausible models have been proposed, we and others previously provided evidence for a coupled exo/phagocytosis model. Herein, we performed histology and immunohistochemistry analyses and demonstrated that a newly developed full-thickness 3D reconstructed human pigmented skin model and an epidermis-only model exhibit dispersed pigment throughout keratinocytes in the epidermis. Transmission electron microscopy revealed melanocores between melanocytes and keratinocytes, suggesting that melanin is transferred through coupled exocytosis/phagocytosis of the melanosome core, or melanocore, similar to our previous observations in human skin biopsies. We therefore present evidence that our in vitro models of pigmented human skin show epidermal pigmentation comparable to human skin. These findings have a high value for studies of skin pigmentation mechanisms and pigmentary disorders, whilst reducing the reliance on animal models and human skin biopsies.publishersversionepub_ahead_of_prin
Glycosylation Affects JUNV GPC Trafficking
Junin virus (JUNV), a highly pathogenic New World arenavirus, is the causative agent of Argentine hemorrhagic fever (AHF). The live-attenuated Candid #1 (Can) strain currently serves as a vaccine for at-risk populations. We have previously shown that the Can glycoprotein (GPC) gene is the primary gene responsible for attenuation in a guinea pig model of AHF. However, the mechanisms through which the GPC contributes to the attenuation of the Can strain remain unknown. A more complete understanding of the mechanisms underlying the attenuation and immunogenicity of the Can strain will potentially allow for the rational design of additional safe and novel vaccines. Here, we provide a detailed comparison of both RNA and protein expression profiles between both inter- and intra-segment chimeric JUNV recombinant clones expressing combinations of genes from the Can strain and the pathogenic Romero (Rom) strain. The recombinant viruses that express Can GPC, which were shown to be attenuated in guinea pigs, displayed different RNA levels and GPC processing patterns as determined by Northern and Western blot analyses, respectively. Analysis of recombinant viruses containing amino acid substitutions selected at different mouse brain passages during the generation of Can revealed that altered Can GPC processing was primarily due to the T168A substitution within G1, which eliminates an N-linked glycosylation motif. Incorporation of the T168A substitution in the Rom GPC resulted in a Can-like processing pattern of Rom GPC. In addition, JUNV GPCs containing T168A substitution were retained within the endoplasmic reticulum (ER) and displayed significantly lower cell surface expression than wild-type Rom GPC. Interestingly, the reversion A168T in Can GPC significantly increased GPC expression at the cell surface. Our results demonstrate that recombinant JUNV (rJUNV) expressing Can GPC display markedly different protein expression and elevated genomic RNA expression when compared to viruses expressing Rom GPC. Additionally, our findings indicate that the N-linked glycosylation motif at amino acid positions 166–168 is important for trafficking of JUNV GPC to the cell surface, and the elimination of this motif interferes with the GPC release from the ER
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