An avian retrovirus uses canonical expression and processing mechanisms to generate viral microRNA

To date, the vast majority of known virus-encoded microRNAs (miRNAs) are derived from polymerase II transcripts encoded by DNA viruses. A recent demonstration that the bovine leukemia virus, a retrovirus, uses RNA polymerase III to directly transcribe the pre-miRNA hairpins to generate viral miRNAs further supports the common notion that the canonical pathway of miRNA biogenesis does not exist commonly among RNA viruses. Here, we show that an exogenous virus-specific region, termed the E element or XSR, of avian leukosis virus subgroup J (ALV-J), a member of avian retrovirus, encodes a novel miRNA, designated E (XSR) miRNA, using the canonical miRNA biogenesis pathway. Detection of novel microRNA species derived from the E (XSR) element, a 148-nucleotide noncoding RNA with hairpin structure, showed that the E (XSR) element has the potential to function as a microRNA primary transcript, demonstrating a hitherto unknown function with possible roles in myeloid leukosis associated with ALV-J

Predicting Risk of Serious Bacterial Infections in Febrile Children in the Emergency Department

BACKGROUND: Improving the diagnosis of serious bacterial infections (SBIs) in the children's emergency department is a clinical priority. Early recognition reduces morbidity and mortality, and supporting clinicians in ruling out SBIs may limit unnecessary admissions and antibiotic use. METHODS: A prospective, diagnostic accuracy study of clinical and biomarker variables in the diagnosis of SBIs (pneumonia or other SBI) in febrile children <16 years old. A diagnostic model was derived by using multinomial logistic regression and internally validated. External validation of a published model was undertaken, followed by model updating and extension by the inclusion of procalcitonin and resistin. RESULTS: There were 1101 children studied, of whom 264 had an SBI. A diagnostic model discriminated well between pneumonia and no SBI (concordance statistic 0.84, 95% confidence interval 0.78-0.90) and between other SBIs and no SBI (0.77, 95% confidence interval 0.71-0.83) on internal validation. A published model discriminated well on external validation. Model updating yielded good calibration with good performance at both high-risk (positive likelihood ratios: 6.46 and 5.13 for pneumonia and other SBI, respectively) and low-risk (negative likelihood ratios: 0.16 and 0.13, respectively) thresholds. Extending the model with procalcitonin and resistin yielded improvements in discrimination. CONCLUSIONS: Diagnostic models discriminated well between pneumonia, other SBIs, and no SBI in febrile children in the emergency department. Improvements in the classification of nonevents have the potential to reduce unnecessary hospital admissions and improve antibiotic prescribing. The benefits of this improved risk prediction should be further evaluated in robust impact studies

Electrostatic phase separation: a review

The current understanding and developments in the electrostatic phase separation are reviewed. The literature covers predominantly two immiscible and inter-dispersed liquids following the last review on the topic some 15 years. Electrocoalescence kinetics and governing parameters, such as the applied field, liquid properties, drop shape and flow, are considered. The unfavorable effects, such as chain formation and partial coalescence, are discussed in detail. Moreover, the prospects of microfluidics platforms, non-uniform fields, coalescence on the dielectric surfaces to enhance the electrocoalescence rate are also considered. In addition to the electrocoalescence in water-in-oil emulsions the research in oil-in-oil coalescence is also discussed. Finally the studies in electrocoalescer development and commercial devices are also surveyed. The analysis of the literature reveals that the use of pulsed DC and AC electric fields is preferred over constant DC fields for efficient coalescence; but the selection of the optimum field frequency a priori is still not possible and requires further research. Some recent studies have helped to clarify important aspects of the process such as partial coalescence and drop–drop non-coalescence. On the other hand, some key phenomena such as thin film breakup and chain formation are still unclear. Some designs of inline electrocoalescers have recently been proposed; however with limited success: the inadequate knowledge of the underlying physics still prevents this technology from leaving the realm of empiricism and fully developing in one based on rigorous scientific methodology

Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees

Background - Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1) a single break-up followed by a long isolation or 2) multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. Results - Our results provide strong evidence that East African endemic lineages of Annonaceae have multiple origins dated to significantly different times spanning the Oligocene and Miocene epochs. Moreover, these successive origins (c. 33, 16 and 8 million years ¿ Myr) coincide with known periods of aridification and geological activity in Africa that would have recurrently isolated the Guineo-Congolian rain forest from the East African one. All East African taxa were found to have diversified prior to Pleistocene times. Conclusion - Molecular phylogenetic dating analyses of this large pan-African clade of Annonaceae unravels an interesting pattern of diversification for rain forest restricted trees co-occurring in West/Central and East African rain forests. Our results suggest that repeated reconnections between the West/Central and East African rain forest blocks allowed for biotic exchange while the break-ups induced speciation via vicariance, enhancing the levels of endemicity. These results provide an explanation for present day distribution patterns and origins of endemicity for African rain forest trees. Moreover, given the pre-Pleistocene origins of all the studied endemic East African genera and species, these results also offer important insights for setting conservation priorities in these highly diversified but threatene