74 research outputs found
Self-stabilizing algorithms for Connected Vertex Cover and Clique decomposition problems
In many wireless networks, there is no fixed physical backbone nor
centralized network management. The nodes of such a network have to
self-organize in order to maintain a virtual backbone used to route messages.
Moreover, any node of the network can be a priori at the origin of a malicious
attack. Thus, in one hand the backbone must be fault-tolerant and in other hand
it can be useful to monitor all network communications to identify an attack as
soon as possible. We are interested in the minimum \emph{Connected Vertex
Cover} problem, a generalization of the classical minimum Vertex Cover problem,
which allows to obtain a connected backbone. Recently, Delbot et
al.~\cite{DelbotLP13} proposed a new centralized algorithm with a constant
approximation ratio of for this problem. In this paper, we propose a
distributed and self-stabilizing version of their algorithm with the same
approximation guarantee. To the best knowledge of the authors, it is the first
distributed and fault-tolerant algorithm for this problem. The approach
followed to solve the considered problem is based on the construction of a
connected minimal clique partition. Therefore, we also design the first
distributed self-stabilizing algorithm for this problem, which is of
independent interest
Diagnostic and prognostic role of TFF3, Romo-1, NF-кB and SFRP4 as biomarkers for endometrial and ovarian cancers: a prospective observational translational study
Purpose: This study aimed to evaluate trefoil factor 3 (TFF3), secreted frizzled-related protein 4 (sFRP4), reactive oxygen species modulator 1 (Romo1) and nuclear factor kappa B (NF-κB) as diagnostic and prognostic markers of endometrial cancer (EC) and ovarian cancer (OC). Methods: Thirty-one patients with EC and 30 patients with OC undergone surgical treatment were enrolled together with 30 healthy controls in a prospective study. Commercial ELISA kits determined serum TFF-3, Romo-1, NF-кB and sFRP-4 concentrations. Results: Serum TFF-3, Romo-1 and NF-кB levels were significantly higher in patients with EC and OC than those without cancer. Regarding EC, none of the serum biomarkers differs significantly between endometrial and non-endometrioid endometrial carcinomas. Mean serum TFF-3 and NF-кB levels were significantly higher in advanced stages. Increased serum levels of TFF-3 and NF-кB were found in those with a higher grade of the disease. Regarding OC, none of the serum biomarkers differed significantly among histological subtypes. Significantly increased serum levels of NF-кB were observed in patients with advanced-stage OC than those with stage I and II diseases. No difference in serum biomarker levels was found between those who had a recurrence and those who had not. The sensibility and specificity of these four biomarkers in discriminating EC and OC from the control group showed encouraging values, although no one reached 70%. Conclusions: TFF-3, Romo-1, NF-кB and SFRP4 could represent new diagnostic and prognostic markers for OC and EC. Further studies are needed to validate our results
Ion channel function of polycystin‐2/polycystin‐1 heteromer revealed by structure‐guided mutagenesis
Mutations in polycystin‐1 (PC1) or polycystin‐2 (PC2) cause autosomal‐dominant polycystic kidney disease (ADPKD). Structural data suggest that one PC1 and three PC2 form heterotetrameric ion channels with an ion permeation pathway blocked by PC1 (R4100, R4107, and H4111) and PC2 (L677, N681) residues. Here, we demonstrate that replacing these residues with alanines results in a gain‐of‐function (GOF) PC2/PC1 construct with distinct selectivity properties compared to PC2 homomers. We also show preferential formation of PC2/PC1 heteromeric complexes over PC2 homomers. Re‐interpretation of published PC2/PC1 cryo‐electron microscopy data, combined with cysteine modification experiments, suggests that the pore‐forming domain of PC1 adopts a canonical TRP channel‐like conformation. This novel PC2/PC1 GOF construct offers the opportunity to investigate the functional impact of ADPKD mutations.Mutations in polycystin‐1 (PC1) or polycystin‐2 (PC2) cause autosomal‐dominant polycystic kidney disease (ADPKD). We generated a novel gain‐of‐function PC2/PC1 heteromeric ion channel by mutating pore‐blocking residues. Moreover, we demonstrated that PC2 will preferentially assemble with PC1 to form heteromeric complexes when PC1 is co‐expressed. Furthermore, we provided evidence for a canonical TRP channel‐like conformation of the PC1 pore loop. imageInterdisziplinäres Zentrum für Klinische Forschung (IZKF, Interdisciplinary Center for Clinical Research Erlangen)Deutsche Forschungsgemeinschaft 10.13039/50110000165
Role of Position 627 of PB2 and the Multibasic Cleavage Site of the Hemagglutinin in the Virulence of H5N1 Avian Influenza Virus in Chickens and Ducks
Highly pathogenic H5N1 avian influenza viruses have caused major disease outbreaks in domestic and free-living birds with transmission to humans resulting in 59% mortality amongst 564 cases. The mutation of the amino acid at position 627 of the viral polymerase basic-2 protein (PB2) from glutamic acid (E) in avian isolates to lysine (K) in human isolates is frequently found, but it is not known if this change affects the fitness and pathogenicity of the virus in birds. We show here that horizontal transmission of A/Vietnam/1203/2004 H5N1 (VN/1203) virus in chickens and ducks was not affected by the change of K to E at PB2-627. All chickens died between 21 to 48 hours post infection (pi), while 70% of the ducks survived infection. Virus replication was detected in chickens within 12 hours pi and reached peak titers in spleen, lung and brain between 18 to 24 hours for both viruses. Viral antigen in chickens was predominantly in the endothelium, while in ducks it was present in multiple cell types, including neurons, myocardium, skeletal muscle and connective tissues. Virus replicated to a high titer in chicken thrombocytes and caused upregulation of TLR3 and several cell adhesion molecules, which may explain the rapid virus dissemination and location of viral antigen in endothelium. Virus replication in ducks reached peak values between 2 and 4 days pi in spleen, lung and brain tissues and in contrast to infection in chickens, thrombocytes were not involved. In addition, infection of chickens with low pathogenic VN/1203 caused neuropathology, with E at position PB2-627 causing significantly higher infection rates than K, indicating that it enhances virulence in chickens
An analytic framework to assess future electricity options in Kosovo
We have developed an analytic platform to analyze the electricity options, costs, and impacts for Kosovo, a nation that is a critical part of the debate over centralized versus distributed electricity generation and the role of fossil fuels versus cleaner electricity options to meet growing demands for power. We find that a range of alternatives exists to meet present supply constraints all at a lower cost than constructing a proposed 600 MW coal plant. The options include energy efficiency measures, combinations of solar PV, wind, hydropower, and biomass, and the introduction of natural gas. A 30 EUR ton-1 shadow price on CO2 increases costs of coal generation by at least 330 million EUR. The results indicate that financing a new coal plant is the most expensive pathway to meet future electricity demand
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An analytic framework to assess future electricity options in Kosovo
We have developed an analytic platform to analyze the electricity options, costs, and impacts for Kosovo, a nation that is a critical part of the debate over centralized versus distributed electricity generation and the role of fossil fuels versus cleaner electricity options to meet growing demands for power. We find that a range of alternatives exists to meet present supply constraints all at a lower cost than constructing a proposed 600 MW coal plant. The options include energy efficiency measures, combinations of solar PV, wind, hydropower, and biomass, and the introduction of natural gas. A 30 EUR ton-1 shadow price on CO2 increases costs of coal generation by at least 330 million EUR. The results indicate that financing a new coal plant is the most expensive pathway to meet future electricity demand
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