The study assessed rates and predictor variables of hepatitis C virus (HCV) infection among drug users receiving pharmacological treatment for opiates addiction.
There was a large cohort study in 16 ...public centres for drug users in north‐eastern Italy, with data collected by standardized face‐to‐face interviews between February 2001 and August 2001.
Of 1095 participants, 74.2% were HCV seropositive. Anti‐HCV status was independently associated with duration of drug use of over 10 years, injecting as a route of drug administration, and hepatitis B virus (HBV) and human immunodeficiency virus (HIV) seropositivity. Further statistical analysis was conducted by dividing the subjects on the basis of the duration of heroin use: more or <10 years. In the multivariate analyses, route of drug administration and HBV status were associated with HCV seropositivity among both groups. Less education was associated with HCV among the shorter term drug users. HIV status and having a sexual partner with a history of drug use were associated with HCV seropositivity among the longer term drug users.
Half of the short‐term heroin users were still HCV seronegative when starting treatment, suggesting opportunities for reducing new HCV infections. Remarkable was the relationship between vaccination for hepatitis B and HCV serostatus. Being HBV seropositive was strongly associated with being HCV seropositive. But heroin users who had been vaccinated for HBV were not significantly more likely to be HCV seropositive than heroin users who were HBV seronegative. HBV vaccination does not provide biological protection against HCV; however, vaccinating heroin users against HBV may help to create a stronger pro‐health attitude among heroin users, leading to a reduction in HCV risk behaviour.
This paper proposes a new prediction-based routing protocol for Delay Tolerant Networks (DTNs) called Greedy Ant (GrAnt). GrAnt uses a greedy transition rule of the Ant Colony Optimization (ACO) ...metaheuristic to provide the exploitation of good previous solutions, when available, and to forward the messages to the most promising node(s). By making use of pheromone concentration and heuristic function, GrAnt protocol provides three modules: scheduling, routing, and buffer management. Simulation results show that in a community-based movement model GrAnt is able to achieve higher successfully message delivery and lower bytes overhead than Epidemic and PROPHET. In a buffer size of 5 MB, for example, GrAnt delivers almost 79 percent of the messages against 39 percent of messages delivered by PROPHET and 45 percent of messages delivered by Epidemic.
Braces were introduced by Rump to study non-degenerate involutive set-theoretic solutions of the Yang-Baxter equation. We generalize Rump's braces to the non-commutative setting and use this new ...structure to study not necessarily involutive non-degenerate set-theoretical solutions of the Yang-Baxter equation. Based on results of Bachiller and Catino and Rizzo, we develop an algorithm to enumerate and construct classical and non-classical braces of small size up to isomorphism. This algorithm is used to produce a database of braces of small size. The paper contains several open problems, questions and conjectures.
We develop a theory of extensions for involutive and nondegenerate solutions of the set-theoretic Yang–Baxter equation and use it to produce new families of solutions. As an application we construct ...an infinite family of counterexamples to a conjecture of Gateva-Ivanova related to the retractability of square-free solutions.
With over 20,000 species, Asteraceae is the second largest plant family. High-throughput sequencing of nuclear and chloroplast genomes has allowed for a better understanding of the evolutionary ...relationships within large plant families. Here, the globe artichoke chloroplast (cp) genome was obtained by a combination of whole-genome and BAC clone high-throughput sequencing. The artichoke cp genome is 152,529 bp in length, consisting of two single-copy regions separated by a pair of inverted repeats (IRs) of 25,155 bp, representing the longest IRs found in the Asteraceae family so far. The large (LSC) and the small (SSC) single-copy regions span 83,578 bp and 18,641 bp, respectively. The artichoke cp sequence was compared to the other eight Asteraceae complete cp genomes available, revealing an IR expansion at the SSC/IR boundary. This expansion consists of 17 bp of the ndhF gene generating an overlap between the ndhF and ycf1 genes. A total of 127 cp simple sequence repeats (cpSSRs) were identified in the artichoke cp genome, potentially suitable for future population studies in the Cynara genus. Parsimony-informative regions were evaluated and allowed to place a Cynara species within the Asteraceae family tree. The eight most informative coding regions were also considered and tested for "specific barcode" purpose in the Asteraceae family. Our results highlight the usefulness of cp genome sequencing in exploring plant genome diversity and retrieving reliable molecular resources for phylogenetic and evolutionary studies, as well as for specific barcodes in plants.
Cancer evolution: Darwin and beyond Vendramin, Roberto; Litchfield, Kevin; Swanton, Charles
The EMBO journal,
15 September 2021, Letnik:
40, Številka:
18
Journal Article
Recenzirano
Odprti dostop
Clinical and laboratory studies over recent decades have established branched evolution as a feature of cancer. However, while grounded in somatic selection, several lines of evidence suggest a ...Darwinian model alone is insufficient to fully explain cancer evolution. First, the role of macroevolutionary events in tumour initiation and progression contradicts Darwin's central thesis of gradualism. Whole‐genome doubling, chromosomal chromoplexy and chromothripsis represent examples of single catastrophic events which can drive tumour evolution. Second, neutral evolution can play a role in some tumours, indicating that selection is not always driving evolution. Third, increasing appreciation of the role of the ageing soma has led to recent generalised theories of age‐dependent carcinogenesis. Here, we review these concepts and others, which collectively argue for a model of cancer evolution which extends beyond Darwin. We also highlight clinical opportunities which can be grasped through targeting cancer vulnerabilities arising from non‐Darwinian patterns of evolution.
Evolutionary concepts explaining cancer progression, the selective pressures acting on tumours, and their therapeutic implications are discussed in this comprehensive review.
Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly ...Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea) distributed across Europe. Adult trees within a given area in each stand were exhaustively sampled (range 239, 754, mean 423), mapped, and acorns were collected (17,147, 51) from several mother trees (3, 47, 23). Seedlings (65,387, 178) were harvested and geo-referenced in six of the eight stands. Genetic information was obtained from screening distinct molecular markers spread across the genome, genotyping each tree, acorn or seedling. All samples were thus genotyped at 5-8 nuclear microsatellite loci. Fathers/parents were assigned to acorns and seedlings using likelihood methods. Mating success of male and female parents, pollen and seed dispersal curves, and also hybridisation rates were estimated in each stand and compared on a continental scale. On average, the percentage of the wind-borne pollen from outside the stand was 60%, with large variation among stands (21-88%). Mean seed immigration into the stand was 40%, a high value for oaks that are generally considered to have limited seed dispersal. However, this estimate varied greatly among stands (20-66%). Gene flow was mostly intraspecific, with large variation, as some trees and stands showed particularly high rates of hybridisation. Our results show that mating success was unevenly distributed among trees. The high levels of gene flow suggest that geographically remote oak stands are unlikely to be genetically isolated, questioning the static definition of gene reserves and seed stands.
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