146 research outputs found
Pump and Dumps in the Bitcoin Era: Real Time Detection of Cryptocurrency Market Manipulations
In the last years, cryptocurrencies are increasingly popular. Even people who
are not experts have started to invest in these securities and nowadays
cryptocurrency exchanges process transactions for over 100 billion US dollars
per month. However, many cryptocurrencies have low liquidity and therefore they
are highly prone to market manipulation schemes. In this paper, we perform an
in-depth analysis of pump and dump schemes organized by communities over the
Internet. We observe how these communities are organized and how they carry out
the fraud. Then, we report on two case studies related to pump and dump groups.
Lastly, we introduce an approach to detect the fraud in real time that
outperforms the current state of the art, so to help investors stay out of the
market when a pump and dump scheme is in action.Comment: Accepted for publication at The 29th International Conference on
Computer Communications and Networks (ICCCN 2020
The Conspiracy Money Machine: Uncovering Telegram's Conspiracy Channels and their Profit Model
In recent years, major social media platforms have implemented increasingly
strict moderation policies, resulting in bans and restrictions on conspiracy
theory-related content. To circumvent these restrictions, conspiracy theorists
are turning to alternatives, such as Telegram, where they can express and
spread their views with fewer limitations. Telegram offers channels -- virtual
rooms where only administrators can broadcast messages -- and a more permissive
content policy. These features have created the perfect breeding ground for a
complex ecosystem of conspiracy channels.
In this paper, we illuminate this ecosystem. First, we propose an approach to
detect conspiracy channels. Then, we discover that conspiracy channels can be
clustered into four distinct communities comprising over 17,000 channels.
Finally, we uncover the "Conspiracy Money Machine," revealing how most
conspiracy channels actively seek to profit from their subscribers. We find
conspiracy theorists leverage e-commerce platforms to sell questionable
products or lucratively promote them through affiliate links. Moreover, we
observe that conspiracy channels use donation and crowdfunding platforms to
raise funds for their campaigns. We determine that this business involves
hundreds of donors and generates a turnover of over $90 million
Association of the mtDNA m.4171C>A/MT-ND1 mutation with both optic neuropathy and bilateral brainstem lesions
Background: An increasing number of mitochondrial DNA (mtDNA) mutations, mainly in complex I genes, have
been associated with variably overlapping phenotypes of Leber’s hereditary optic neuropathy (LHON),
mitochondrial encephalomyopathy with stroke-like episodes (MELAS) and Leigh syndrome (LS). We here describe
the first case in which the m.4171C>A/MT-ND1 mutation, previously reported only in association with LHON, leads
also to a Leigh-like phenotype.
Case presentation: A 16-year-old male suffered subacute visual loss and recurrent vomiting and vertigo associated
with bilateral brainstem lesions affecting the vestibular nuclei. His mother and one sister also presented subacute
visual loss compatible with LHON. Sequencing of the entire mtDNA revealed the homoplasmic m.4171C>A/MT-ND1
mutation, previously associated with pure LHON, on a haplogroup H background. Three additional non-synonymous
homoplasmic transitions affecting ND2 (m.4705T>C/MT-ND2 and m.5263C>T/MT-ND2) and ND6 (m.14180T>C/MT-ND6)
subunits, well recognized as polymorphisms in other mtDNA haplogroups but never found on the haplogroup H
background, were also present.
Conclusion: This case widens the phenotypic expression of the rare m.4171C>A/MT-ND1 LHON mutation, which
may also lead to Leigh-like brainstem lesions, and indicates that the co-occurrence of other ND non-synonymous
variants, found outside of their usual mtDNA backgrounds, may have increased the pathogenic potential of the
primary LHON mutation
Macular Microcysts in Mitochondrial Optic Neuropathies: Prevalence and Retinal Layer Thickness Measurements.
PurposeTo investigate the thickness of the retinal layers and to assess the prevalence of macular microcysts (MM) in the inner nuclear layer (INL) of patients with mitochondrial optic neuropathies (MON).MethodsAll patients with molecularly confirmed MON, i.e. Leber's Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), referred between 2010 and 2012 were enrolled. Eight patients with MM were compared with two control groups: MON patients without MM matched by age, peripapillary retinal nerve fiber layer (RNFL) thickness, and visual acuity, as well as age-matched controls. Retinal segmentation was performed using specific Optical coherence tomography (OCT) software (Carl Zeiss Meditec). Macular segmentation thickness values of the three groups were compared by one-way analysis of variance with Bonferroni post hoc corrections.ResultsMM were identified in 5/90 (5.6%) patients with LHON and 3/58 (5.2%) with DOA. The INL was thicker in patients with MON compared to controls regardless of the presence of MM [133.1±7μm vs 122.3±9μm in MM patients (p<0.01) and 128.5±8μm vs. 122.3±9μm in no-MM patients (p<0.05)], however the outer nuclear layer (ONL) was thicker in patients with MM (101.4±1mμ) compared to patients without MM [77.5±8mμ (p<0.001)] and controls [78.4±7mμ (p<0.001)]. ONL thickness did not significantly differ between patients without MM and controls.ConclusionThe prevalence of MM in MON is low (5-6%), but associated with ONL thickening. We speculate that in MON patients with MM, vitreo-retinal traction contributes to the thickening of ONL as well as to the production of cystic spaces
Prognostic accuracy of Prostate Health Index and urinary Prostate Cancer Antigen 3 in predicting pathologic features after radical prostatectomy
Objective: To compare the prognostic accuracy of Prostate Health Index (PHI) and Prostate Cancer Antigen 3 in predicting pathologic features in a cohort of patients who underwent radical prostatectomy (RP) for prostate cancer (PCa). Methods and materials: We evaluated 156 patients with biopsy-proven, clinically localized PCa who underwent RP between January 2013 and December 2013 at 2 tertiary care institutions. Blood and urinary specimens were collected before initial prostate biopsy for [-2] pro-prostate-specific antigen (PSA), its derivates, and PCA3 measurements. Univariate and multivariate logistic regression analyses were carried out to determine the variables that were potentially predictive of tumor volume >0.5. ml, pathologic Gleason sum 657, pathologically confirmed significant PCa, extracapsular extension, and seminal vesicles invasions. Results: On multivariate analyses and after bootstrapping with 1,000 resampled data, the inclusion of PHI significantly increased the accuracy of a baseline multivariate model, which included patient age, total PSA, free PSA, rate of positive cores, clinical stage, prostate volume, body mass index, and biopsy Gleason score (GS), in predicting the study outcomes. Particularly, to predict tumor volume>0.5, the addition of PHI to the baseline model significantly increased predictive accuracy by 7.9% (area under the receiver operating characteristics curve [AUC] = 89.3 vs. 97.2, P>0.05), whereas PCA3 did not lead to a significant increase.Although both PHI and PCA3 significantly improved predictive accuracy to predict extracapsular extension compared with the baseline model, achieving independent predictor status (all P's<0.01), only PHI led to a significant improvement in the prediction of seminal vesicles invasions (AUC = 92.2, P<0.05 with a gain of 3.6%).In the subset of patients with GS 646, PHI significantly improved predictive accuracy by 7.6% compared with the baseline model (AUC = 89.7 vs. 97.3) to predict pathologically confirmed significant PCa and by 5.9% compared with the baseline model (AUC = 83.1 vs. 89.0) to predict pathologic GS 657. For these outcomes, PCA3 did not add incremental predictive value. Conclusions: In a cohort of patients who underwent RP, PHI is significantly better than PCA3 in the ability to predict the presence of both more aggressive and extended PCa
Deciphering OPA1 mutations pathogenicity by combined analysis of human, mouse and yeast cell models
OPA1 is the major gene responsible for Dominant Optic Atrophy (DOA) and the syndromic form DOA “plus”. Over 370 OPA1 mutations have been identified so far, although their pathogenicity is not always clear. We have analyzed one novel and a set of known OPA1 mutations to investigate their impact on protein functions in primary skin fibroblasts and in two “ad hoc” generated cell systems: the MGM1/OPA1 chimera yeast model and the Opa1−/− MEFs model expressing the mutated human OPA1 isoform 1. The yeast model allowed us to confirm the deleterious effects of these mutations and to gain information on their dominance/recessivity. The MEFs model enhanced the phenotypic alteration caused by mutations, nicely correlating with the clinical severity observed in patients, and suggested that the DOA “plus” phenotype could be induced by the combinatorial effect of mitochondrial network fragmentation with variable degrees of mtDNA depletion. Overall, the two models proved to be valuable tools to functionally assess and define the deleterious mechanism and the pathogenicity of novel OPA1 mutations, and useful to testing new therapeutic interventions
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