633 research outputs found
On the simplest centralizer of a language
Given a finite alphabet ÎŁ and a language
L â â+,
the centralizer of L is defined as the maximal language commuting with it.
We prove that if the primitive root of the smallest word of L (with respect to a lexicographic order) is prefix distinguishable in L then the centralizer of L
is as simple as possible, that is, the submonoid
L*.
This lets us obtain a simple proof of a known result concerning the centralizer of nonperiodic three-word languages
Surveillance of Ruminant Diseases in the Nordic Countries
<p/> <p>All the Nordic countries have a basis for their surveillance and disease control in ruminants in national legislation and regulations listing notifiable diseases of concern to the countries. The Nordic countries are a disease-free zone comparing to other parts of the world and the aim of the surveillance is to keep that status and be able to document it. Following is a short summary from each country.</p
PRODUCT LIFECYCLE DATA SHARING AND VISUALISATION: WEB-BASED APPROACHES
Both product design and manufacturing are intrinsically collaborative processes. From conception and design to project completion and ongoing maintenance, all points in the lifecycle of any product involve the work of fluctuating teams of designers, suppliers and customers. That is why companies are involved in the creation of a distributed design and a manufacturing environment which could provide an effective way to communicate and share information throughout the entire enterprise and the supply chain. At present, the technologies that support such a strategy are based on World Wide Web platforms and follow two different paths. The first one focuses on 2D documentation improvement and introduces 3D interactive information in order to add knowledge to drawings. The second one works directly on 3D models and tries to extend the life of 3D data moving these design information downstream through the entire product lifecycle. Unfortunately the actual lack of a unique 3D Web-based standard has stimulated the growing up of many different proprietary and open source standards and, as a consequence, a production of an incompatible information exchange over the WEB. This paper proposes a structured analysis of Web-based solutions, trying to identify the most critical aspects to promote a unique 3D digital standard model capable of sharing product and manufacturing data more effectivelyâregardless of geographic boundaries, data structures, processes or computing environmen
Nuclear translocation of vitellogenin in the honey bee (Apis mellifera)
Vitellogenin (Vg) is a conserved protein used by nearly all oviparous animals to produce eggs. It is also pleiotropic and performs functions in oxidative stress resistance, immunity, and, in honey bees, behavioral development of the worker caste. It has remained enigmatic how Vg affects multiple traits. Here, we asked whether Vg enters the nucleus and acts via DNA-binding. We used cell fractionation, immunohistology, and cell culture to show that a structural subunit of honey bee Vg translocates into cell nuclei. We then demonstrated Vg-DNA binding theoretically and empirically with prediction software and chromatin immunoprecipitation with sequencing (ChIP-seq), finding binding sites at genes influencing immunity and behavior. Finally, we investigated the immunological and enzymatic conditions affecting Vg cleavage and nuclear translocation and constructed a 3D structural model. Our data are the first to show Vg in the nucleus and suggest a new fundamental regulatory role for this ubiquitous protein.Peer reviewe
Safe and complete contig assembly via omnitigs
Contig assembly is the first stage that most assemblers solve when
reconstructing a genome from a set of reads. Its output consists of contigs --
a set of strings that are promised to appear in any genome that could have
generated the reads. From the introduction of contigs 20 years ago, assemblers
have tried to obtain longer and longer contigs, but the following question was
never solved: given a genome graph (e.g. a de Bruijn, or a string graph),
what are all the strings that can be safely reported from as contigs? In
this paper we finally answer this question, and also give a polynomial time
algorithm to find them. Our experiments show that these strings, which we call
omnitigs, are 66% to 82% longer on average than the popular unitigs, and 29% of
dbSNP locations have more neighbors in omnitigs than in unitigs.Comment: Full version of the paper in the proceedings of RECOMB 201
A multilevel layout algorithm for visualizing physical and genetic interaction networks, with emphasis on their modular organization
Adolescent survey non-response and later risk of death. A prospective cohort study of 78 609 persons with 11-year follow-up
<p>Abstract</p> <p>Background</p> <p>Non-response in survey studies is a growing problem and, being usually selective, it leads to under- or overestimation of health outcomes in the follow-up. We followed both respondents and non-respondents by registry linkage to determine whether there is a risk of death, related to non-response at baseline.</p> <p>Methods</p> <p>Sample data of biennial surveys to 12-18-year-old Finns in 1979â1997 were linked with national death registry up to 2001. The number of respondents was 62 528 (79.6%) and non-respondents 16 081 (20.4%). The average follow-up was 11.1 years, totalling 876 400 person-years. The risk of death between non-respondents and respondents was estimated by hazard ratios (HR).</p> <p>Results</p> <p>The number of deaths per 100 000 person-years were 229 in non-respondents and 447 in respondents (HR 2.0, 95% CI: 1.5â2.6). The hazard ratios of death were for intoxication 3.2 (95% CI: 1.9â5.4), for disease 3.1 (95% CI: 2.2â4.1), for violence-related injury 2.0 (95% CI: 1.5â2.6) and for unintentional injury 1.8 (95% CI: 1.3â2.4) in non-respondents vs. respondents. The association between non-response and death increased with age at baseline, and the increase persisted after the age of 25.</p> <p>Conclusion</p> <p>Our study demonstrated significantly increased rates of death among adolescent non-respondents in a follow-up. The highest hazard ratios were seen in disease- and violence-related deaths. The death rate varied between respondents and non-respondents by death type. Increased rates of death persisted beyond the age of 25.</p
Pre-transplant donor-specific anti-human leukocyte antigen antibodies are associated with high risk of delayed graft function after renal transplantation
Sensitive screening methods have revealed that many patients have donor-specific human leucocyte antigen antibodies (DSAs) prior to transplantation, regardless of negative crossmatch results. The clinical significance of pre-transplant (pre-Tx) DSAs for early graft function has remained unclear. Our aim was to examine the association of DSAs with delayed graft function (DGF). Pre-Tx sera of 771 patients who received kidney transplants in our single-centre study were retrospectively screened. All transplantations were performed after negative complement-dependent cytotoxicity (CDC) crossmatch. DSAs were detected in 13% of the patients. The overall DGF rate in our study was 29%. Patients with DSAs had a higher incidence of DGF when compared with non-sensitized patients (48 and 26%, respectively; P <0.0001). Third-party antibodies had no effect for DGF incidence (28%; P = 0.6098). The relative risk (RR) of DGF for patients with DSAs in the multivariate analysis was 2.039 (95% CI 1.246-3.335; P = 0.0046). Analyses of the cumulative mean fluorescent intensity (MFI) value of the DSAs revealed a rate of DGF more than two times higher in patients with a cumulative value of 3000-5000 MFI compared with a cumulative value of 1000-3000 (65 versus 31%; P = 0.0351). DSAs against any loci showed an elevated DGF incidence of 44-69% when compared with patients without DSA (27%). The risk of DGF is twice as high in patients having pre-formed DSAs. Pre-Tx DSAs is a modifiable risk factor that can be obviated with careful organ allocation relying on careful pre-Tx analysis of non-accepted mismatches determined with sensitive solid phase methods.Peer reviewe
Novel pyrimidine-2,4-diamine derivative suppresses the cell viability and spindle assembly checkpoint activity by targeting Aurora kinases
Mitosis represents a clinically important determination point in the life cycle of proliferating cells. One potential drug target within the mitotic machinery is the spindle assembly checkpoint (SAC), an evolutionarily conserved signaling pathway that monitors the connections between microtubules (MTs) and chromosomes. Mistakes in SAC signaling may lead to cell division errors that can trigger elimination of cancer cells at M phase or soon after exit from mitosis. In this study, we describe the cellular effects of a novel pyrimidine-2,4-diamine derivative that we discovered to inhibit the activity of SAC. The compound caused rapid escape from the mitotic arrest induced by lack of interkinetochore tension but not by lack of MT-kinetochore attachments. In cycling cells, the compound disrupted the architecture of mitotic spindle that triggered a transient M-phase arrest that was rapidly followed by a forced mitotic exit. The premature termination of M phase was found to be a consequence of precocious inactivation of SAC caused by a direct inhibitory effect of the compound on Aurora B kinase in vitro and in cells. The compound also targets Aurora A kinase and tubulin in vitro and in cells, which can explain the observed spindle anomalies. The reduced activity of Aurora B kinase resulted in polyploidy and suppression of cancer cell viability. Our data suggest that this new pharmacophore possesses interesting anticancer properties that could be exploited in development of mitosis-targeting therapies
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