Quantifying the impact of small variations in fracture geometric characteristics on peak rock mass properties at a mining project using a coupled DFN–DEM approach

Using field data from Agnico-Eagle’s Meliadine gold project located in Nunavut Territory in northern Canada, a coupled DFN–DEM approach was used to evaluate the rock mass mechanical properties at REV. Variability in the structural data gathered on site and the variability associated with the stochastic modeling process have an impact on discrete fracture model (DFN) properties. Through a sensitivity analysis, this paper assesses the influence of a variation in the DFN model input parameters’ values on the rock mass peak properties – uniaxial compressive strength, Young modulus and Poisson ratio. The results not only highlight the possibilities associated with DFN–DEM modeling in characterizing rock mass properties at the engineering scale, they also provide a systematic way to assess the critical structural parameters controlling the rock mass properties

Methanol-Driven Oxidative Rearrangement of Biogenic Furans - Enzyme Cascades vs. Photobiocatalysis

The oxidative ring expansion of bio-derived furfuryl alcohols to densely functionalized six-membered O-heterocycles represents an attractive strategy in the growing network of valorization routes to synthetic building blocks out of the lignocellulosic biorefinery feed. In this study, two scenarios for the biocatalytic Achmatowicz-type rearrangement using methanol as terminal sacrificial reagent have been evaluated, comparing multienzymatic cascade designs with a photo-bio-coupled activation pathway.Peer reviewe

Divorticity and Dihelicity In Two-Dimensional Hydrodynamics

A framework is developed based on the concepts of {\it divorticity} ${\textbf B}$(\equiv\nabla\times\bfo, \bfo being the vorticity) and \textit{dihelicity} g \lp \equiv\bfv\cdot\textbf{B}\rp for discussing the theoretical structure underlying two-dimensional (2D) hydrodynamics. This formulation leads to the global and Lagrange invariants that could impose significant constraints on the evolution of divorticity lines in 2D hydrodynamics

Caractérisation statistique de la résistance en compression uniaxiale, de la résistance en tension et de l’indice de double poinçonnement du roc intact pour un projet minier

The design of excavation in underground mines relies on rock mass characterization. Intact rock properties are assessed according to the guidelines suggested by the International Society for Rock Mechanics. For laboratory testing, a minimum number of specimens must be analysed. This number is specific for a given test type. Nonetheless, rock variability, heterogeneity and anisotropy may suggest that a larger number of specimens could be necessary to fully assess rock mass properties. Furthermore, a characterization campaign must also respect certain practical and financial limitations. Using a case study from a Quebec mine site, this paper presents a methodology that allows directly linking the results of statistical analysis on campaign results to target levels of confidence for geotechnical data at all stages of a mining project

Estimating the contribution of stimulant injection to HIV and HCV epidemics among people who inject drugs and implications for harm reduction:A modeling analysis

BACKGROUND: Stimulants, such as amphetamines and cocaine, are widely injected among people who inject drugs (PWID). Systematic reviews indicate stimulant injection is associated with HIV and HCV among PWID. Using these associations, we estimated the contribution of stimulant injection to HIV and HCV transmission among PWID. METHODS: We modeled HIV and HCV transmission among PWID, incorporating excess injecting and sexual risk among PWID who inject stimulants. We simulated three illustrative settings with different stimulants injected, prevalence of stimulant injecting, and HIV/HCV epidemiology. We estimated one-year population attributable fractions of stimulant injection on new HIV and HCV infections, and impact of scaling up needle-syringe programs (NSP). RESULTS: In low prevalence settings of stimulant injection (St. Petersburg-like, where 13% inject amphetamine), 9% (2.5-97.5% interval [95%I]: 6-15%) and 7% (95%I 4-11%) of incident HIV and HCV cases, respectively, could be associated with stimulant injection in the next year. With moderate stimulant injection (Montreal-like, where 34% inject cocaine), 29% (95%I: 19–37%) and 19% (95%I: 16-21%) of incident HIV and HCV cases, respectively, could be associated with stimulant injection. In high-burden settings like Bangkok where 65% inject methamphetamine, 23% (95%I:10–34%) and 20% (95%I: 9-27%) of incident HIV and HCV cases could be due to stimulant injection. High-coverage NSP (60%) among PWID who inject stimulants could reduce HIV (by 22-65%) and HCV incidence (by 7-11%) in a decade. DISCUSSION: Stimulant injection contributes substantially to HIV and HCV among PWID. NSP scale-up and development of novel interventions among PWID who inject stimulants are warranted

Experimental study of Taylor's hypothesis in a turbulent soap film

An experimental study of Taylor's hypothesis in a quasi-two-dimensional turbulent soap film is presented. A two probe laser Doppler velocimeter enables a non-intrusive simultaneous measurement of the velocity at spatially separated points. The breakdown of Taylor's hypothesis is quantified using the cross correlation between two points displaced in both space and time; correlation is better than 90% for scales less than the integral scale. A quantitative study of the decorrelation beyond the integral scale is presented, including an analysis of the failure of Taylor's hypothesis using techniques from predictability studies of turbulent flows. Our results are compared with similar studies of 3D turbulence.Comment: 27 pages, + 19 figure

Loss of 5-hydroxymethylcytosine is a frequent event in peripheral T-cell lymphomas.

International audienc

Incarceration history and risk of HIV and hepatitis C virus acquisition among people who inject drugs: a systematic review and meta-analysis

Background People who inject drugs (PWID) experience a high prevalence of incarceration and might be at high risk of HIV and hepatitis C virus (HCV) infection during or after incarceration. We aimed to assess whether incarceration history elevates HIV or HCV acquisition risk among PWID. Methods In this systematic review and meta-analysis, we searched MEDLINE, Embase, and PsycINFO databases for studies in any language published from Jan 1, 2000 until June 13, 2017 assessing HIV or HCV incidence among PWID. We included studies that measured HIV or HCV incidence among community-recruited PWID. We included only studies reporting original results and excluded studies that evaluated incident infections by self-report. We contacted authors of cohort studies that met the inclusion or exclusion criteria, but that did not report on the outcomes of interest, to request data. We extracted and pooled data from the included studies using random-effects meta-analyses to quantify the associations between recent (past 3, 6, or 12 months or since last follow-up) or past incarceration and HIV or HCV acquisition (primary infection or reinfection) risk among PWID. We assessed the risk of bias of included studies using the Newcastle-Ottawa Scale. Between-study heterogeneity was evaluated using the I2 statistic and the P-value for heterogeneity. Findings We included published results from 20 studies and unpublished results from 21 studies. These studies originated from Australasia, western and eastern Europe, North and Latin America, and east and southeast Asia. Recent incarceration was associated with an 81% (relative risk [RR] 1·81, 95% CI 1·40–2·34) increase in HIV acquisition risk, with moderate heterogeneity between studies (I2=63·5%; p=0·001), and a 62% (RR 1·62, 95% CI 1·28–2·05) increase in HCV acquisition risk, also with moderate heterogeneity between studies (I2=57·3%; p=0·002). Past incarceration was associated with a 25% increase in HIV (RR 1·25, 95% CI 0·94–1·65) and a 21% increase in HCV (1·21, 1·02–1·43) acquisition risk. Interpretation Incarceration is associated with substantial short-term increases in HIV and HCV acquisition risk among PWID and could be a significant driver of HCV and HIV transmission among PWID. These findings support the need for developing novel interventions to minimise the risk of HCV and HIV acquisition, including addressing structural risks associated with drug laws and excessive incarceration of PWID

Activating mutations in genes related to TCR signaling in angioimmunoblastic and other follicular helper T-cell-derived lymphomas.

Angioimmunoblastic T-cell lymphoma (AITL) and other lymphomas derived from follicular T-helper cells (TFH) represent a large proportion of peripheral T-cell lymphomas (PTCLs) with poorly understood pathogenesis and unfavorable treatment results. We investigated a series of 85 patients with AITL (n = 72) or other TFH-derived PTCL (n = 13) by targeted deep sequencing of a gene panel enriched in T-cell receptor (TCR) signaling elements. RHOA mutations were identified in 51 of 85 cases (60%) consisting of the highly recurrent dominant negative G17V variant in most cases and a novel K18N in 3 cases, the latter showing activating properties in in vitro assays. Moreover, half of the patients carried virtually mutually exclusive mutations in other TCR-related genes, most frequently in PLCG1 (14.1%), CD28 (9.4%, exclusively in AITL), PI3K elements (7%), CTNNB1 (6%), and GTF2I (6%). Using in vitro assays in transfected cells, we demonstrated that 9 of 10 PLCG1 and 3 of 3 CARD11 variants induced MALT1 protease activity and increased transcription from NFAT or NF-κB response element reporters, respectively. Collectively, the vast majority of variants in TCR-related genes could be classified as gain-of-function. Accordingly, the samples with mutations in TCR-related genes other than RHOA had transcriptomic profiles enriched in signatures reflecting higher T-cell activation. Although no correlation with presenting clinical features nor significant impact on survival was observed, the presence of TCR-related mutations correlated with early disease progression. Thus, targeting of TCR-related events may hold promise for the treatment of TFH-derived lymphomas