2,753 research outputs found
Classifying the content of online notepad services using active learning
Get PDFPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE[EN] Pastebin is an online notepad service to share text anonymously. However, it could be misused
to propagate suspicious or even illegal activities, like leaking sensitive information or sharing
hyperlinks to child sexual abuse material. Due to the high rate of daily upload pastes, manual
inspection of this material is not feasible. Conversely, an automatic classifier could identify
such activities with little or no human intervention. However, a supervised model may require
a significant number of training samples and have to handle distinct text typologies presented
in Pastebin. This paper presents a classification approach composed of three cascading supervised classifiers that use Active Learning to select and label the most informative samples
from Pastebin. The modularity of the proposed design allows each classifier to adapt to a
specific text typology. The first classifier determines whether the text is a code snippet, and
the second is to identify whether it is readable. The third classification level is twofold: (i) a
binary classifier to say whether the text is suspicious and (ii) a multiclass classifier with seven
predefined categories of possibly illegal activities. The average class recall of the binary and
multiclass classifiers is 95.24% and 80.33%, respectively. Additionally, this paper presents a
dataset of 3.8 million Pastebin samples, called onlIne Notepad Services PastEbin aCtiviTies
(INSPECT-3.8M), along with their labels using our classification framework. Our classifier recognised that 7.54% of the collected samples are correlated with presumably criminal
activities. Law enforcement agencies may benefit from the insights shared in our research
when aiming to investigate or automate the monitoring of Pastebin or other Online Notepad
Services. This would allow responsible authorities to block illegal content before it spreads
to the public.SIOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature
The Structure of Isolated Synechococcus Strain WH8102 Carboxysomes as Revealed by Electron Cryotomography
Get PDFCarboxysomes are organelle-like polyhedral bodies found in cyanobacteria and many chemoautotrophic bacteria that are thought to facilitate carbon fixation. Carboxysomes are bounded by a proteinaceous outer shell and filled with ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO), the first enzyme in the CO_2 fixation pathway, but exactly how they enhance carbon fixation is unclear. Here we report the three-dimensional structure of purified carboxysomes from Synechococcus species strain WH8102 as revealed by electron cryotomography. We found that while the sizes of individual carboxysomes in this organism varied from 114 nm to 137 nm, surprisingly, all were approximately icosahedral. There were on average ~250 RuBisCOs per carboxysome, organized into three to four concentric layers. Some models of carboxysome function depend on specific contacts between individual RuBisCOs and the shell, but no evidence of such contacts was found: no systematic patterns of connecting densities or RuBisCO positions against the shell's presumed hexagonal lattice could be discerned, and simulations showed that packing forces alone could account for the layered organization of RuBisCOs
In Vitro Assessment of Bio-Functional Properties from Lactiplantibacillus plantarum Strains
Get PDFIn recent years, alongside the conventional screening procedures for the evaluation of probiotics for human usage, the pharmaceutical and food industries have encouraged scientific research towards the selection of new probiotic bacterial strains with particular functional features. Therefore, this study intended to explore novel functional properties of five Lactiplantibacillus plantarum strains isolated from bee bread. Specifically, antioxidant, antimicrobial and β-glucosidase activities, exopolysaccharides (EPS) production and the ability to synthesize γ-aminobutyric acid (GABA) were evaluated. The results demonstrated that the investigated L. plantarum strains were effective in inhibiting the growth of some human opportunistic pathogens in vitro (Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Enterococcus faecalis and Staphylococcus aureus). Moreover, the evaluation of antioxidant and β-glucosidase activity and of EPS and GABA production, revealed a different behavior among the strains, testifying how these properties are strongly strain-dependent. This suggests that a careful selection within a given species is important in order to identify appropriate strains for specific biotechnological applications. The results highlighted that the five strains of L. plantarum are promising candidates for application as dietary supplements in the human diet and as microbial cultures in specific food productions
DNA Damage Repair Kinase DNA-Pk and cGAS Synergize To Induce Cancer-Related Inflammation in Glioblastoma
Get PDFCytosolic DNA promotes inflammatory responses upon detection by the cyclic GMP-AMP (cGAMP) synthase (cGAS). It has been suggested that cGAS downregulation is an immune escape strategy harnessed by tumor cells. Here, we used glioblastoma cells that show undetectable cGAS levels to address if alternative DNA detection pathways can promote pro-inflammatory signaling. We show that the DNA-PK DNA repair complex (i) drives cGAS-independent IRF3-mediated type I Interferon responses and (ii) that its catalytic activity is required for cGAS-dependent cGAMP production and optimal downstream signaling. We further show that the cooperation between DNA-PK and cGAS favors the expression of chemokines that promote macrophage recruitment in the tumor microenvironment in a glioblastoma model, a process that impairs early tumorigenesis but correlates with poor outcome in glioblastoma patients. Thus, our study supports that cGAS-dependent signaling is acquired during tumorigenesis and that cGAS and DNA-PK activities should be analyzed concertedly to predict the impact of strategies aiming to boost tumor immunogenicity
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