Student-led podcasting for engineering education

The use of podcasts is challenging traditional communication methods in higher education, with the potential for creating highly engaging and flexible resources for learning and development. In a similar way, podcasts are helping to facilitate a stronger student identity and community within learning environments, replacing traditional student newsletter and website approaches. In this work, an innovative podcasting approach is presented in which there is a strong student-centred and student-led premise to foster and advance engineering education related uses. Podcasts are intended to cover a range of relevant engineering topics such as sharing student views on global and scientific developments, raising issues for current matters important to students and disseminating information on unique educational opportunities. Details on the set-up of the initiative are presented, and include resource requirements, management and organisation structures for an effective interface between academic staff and the student podcasting team, and mechanisms for ensuring that the podcasts maintain balanced educational outcomes

Flow of DNA solutions in a microfluidic gradual contraction

The flow of λ-DNA solutions in a gradual micro-contraction was investigated using direct measurement techniques. The effects on DNA transport in microscale flows are significant because the flow behavior is influenced by macromolecular conformations, both viscous and elastic forces dominate inertial forces at this length scale, and the fully extended length of the molecule approaches the characteristic channel length wc (L/wc ∼ 0.13). This study examines the flow of semi-dilute and entangled DNA solutions in a gradual planar micro-contraction for low Reynolds numbers (3.7 × 10−6 \u3c Re \u3c 3.1 × 10−1) and high Weissenberg numbers (0.4 \u3c Wi \u3c 446). The semi-dilute DNA solutions have modest elasticity number, El = Wi/Re = 55, and do not exhibit viscoelastic behavior. For the entangled DNA solutions, we access high elasticity numbers (7.9 × 103 \u3c El \u3c 6.0 × 105). Video microscopy and streak images of entangled DNA solution flow reveal highly elastic behavior evidenced by the presence of large, stable vortices symmetric about the centerline and upstream of the channel entrance. Micro-particle image velocimetry measurements are used to obtain high resolution, quantitative velocity measurements of the vortex growth in this micro-contraction flow. These direct measurements provide a deeper understanding of the underlying physics of macromolecular transport in microfluidic flow, which will enable the realization of enhanced designs of lab-on-a-chip systems

Deletions of neuraminidase and resistance to oseltamivir may be a consequence of restricted receptor specificity in recent H3N2 influenza viruses

<p>Abstract</p> <p>Background</p> <p>Influenza viruses attach to cells via sialic acid receptors. The viral neuraminidase (NA) is needed to remove sialic acids so that newly budded virions can disperse. Known mechanisms of resistance to NA inhibitors include mutations in the inhibitor binding site, or mutations in the hemagglutinin that reduce avidity for sialic acid and therefore reduce the requirement for NA activity.</p> <p>Results</p> <p>Influenza H3N2 isolates A/Oklahoma/323/03 (Fujian-like), A/Oklahoma/1992/05 (California-like), and A/Oklahoma/309/06 (Wisconsin-like) lost NA activity on passage in MDCK cells due to internal deletions in the NA-coding RNA segment. The viruses grow efficiently in MDCK cells despite diminished NA activity. The full length NA enzyme activity is sensitive to oseltamivir but replication of A/Oklahoma/323/03 and A/Oklahoma/309/06 in MDCK cells was resistant to this inhibitor, indicating that NA is not essential for replication. There was no change in HA activity or sequence after the NA activity was lost but the three viruses show distinct, quite restricted patterns of receptor specificity by Glycan Array analysis. Extensive predicted secondary structure in RNA segment 6 that codes for NA suggests the deletions are generated by polymerase skipping over base-paired stem regions. In general the NA deletions were not carried into subsequent passages, and we were unable to plaque-purify virus with a deleted NA RNA segment.</p> <p>Conclusion</p> <p>H3N2 viruses from 2003 to the present have reduced requirement for NA when passaged in MDCK cells and are resistant to NA inhibitors, possibly by a novel mechanism of narrow receptor specificity such that virus particles do not self-aggregate. These viruses delete internal regions of the NA RNA during passage and are resistant to oseltamivir. However, deletions are independently generated at each passage, suggesting that virus with a full length NA RNA segment initiates the first round of infection.</p

Receptor binding specificity of recent human H3N2 influenza viruses

<p>Abstract</p> <p>Background</p> <p>Human influenza viruses are known to bind to sialic acid linked α2-6 to galactose, but the binding specificity beyond that linkage has not been systematically examined. H3N2 human influenza isolates lost binding to chicken red cells in the 1990s but viruses isolated since 2003 have re-acquired the ability to agglutinate chicken erythrocytes. We have investigated specificity of binding, changes in hemagglutinin sequence of the recent viruses and the role of sialic acid in productive infection.</p> <p>Results</p> <p>Viruses that agglutinate, or do not agglutinate, chicken red cells show identical binding to a Glycan Array of 264 oligosaccharides, binding exclusively to a subset of α2-6-sialylsaccharides. We identified an amino acid change in hemagglutinin that seemed to correlate with chicken red cell binding but when tested by mutagenesis there was no effect. Recombinant hemagglutinins expressed on Sf-9 cells bound chicken red cells but the released recombinant baculoviruses agglutinated only human red cells. Similarly, an isolate that does not agglutinate chicken red cells show hemadsorption of chicken red cells to infected MDCK cells. We suggest that binding of chicken red cells to cell surface hemagglutinin but not to virions is due to a more favorable hemagglutinin density on the cell surface. We investigated whether a virus specific for α2-6 sialyloligosaccharides shows differential entry into cells that have varying proportions of α2-6 and α2-3 sialic acids, including human A549 and HeLa cells with high levels of α2-6 sialic acid, and CHO cells that have only α2-3 sialic acid. We found that the virus enters all cell types tested and synthesizes viral nucleoprotein, localized in the nucleus, and hemagglutinin, transported to the cell surface, but infectious progeny viruses were released only from MDCK cells.</p> <p>Conclusion</p> <p>Agglutination of chicken red cells does not correlate with altered binding to any oligosaccharide on the Glycan Array, and may result from increased avidity due to density of hemagglutinin and not increased affinity. Absence of α2-6 sialic acid does not protect a cell from influenza infection and the presence of high levels of α2-6-sialic acids on a cell surface does not guarantee productive replication of a virus with α2-6 receptor specificity.</p

Rapid cell extraction in aqueous two-phase microdroplet systems

Distinguishing specific cells is an essential technique in cell research and clinical diagnostics. We report a novel method to passively isolate and extract cells in a microfluidic device. We utilise a droplet-based microfluidic system to generate an aqueous two phase system in which aqueous droplets consist of two phases in the form of a double emulsion. Specifically, we generate PEG droplets that completely encapsulate DEX droplets within a microfluidic channel. Target cells can be introduced directly into the droplets and driven to partition to the more favourable phase, whilst still being contained within the aqueous droplet. Human T lymphoma cells, with diameters in the range of 10–15 μm, are chosen as a model cell line to demonstrate the partitioning

Sacrospinous colpopexy versus McCall’s culdoplasty during vaginal hysterectomy in stage 3 and 4 prolapse for prevention of vault prolapse

Background: Pelvic organ prolapse is a common condition seen in women due to weakening of support of pelvic organs. Different surgical procedures have been adopted for suspension of vaginal vault during vaginal hysterectomy to restore vault to near normal anatomic position as preventive measures for vault prolapse. The aim of study was to compare the efficacy of the McCall’s culdoplasty and sacrospinous ligament colpopexy in stage 3 and 4 prolapse (POP-Q).Methods: This prospective study comprised 100 women presenting with stage 3 and 4 prolapse (POP-Q). They were divided into two equal groups of 50 each. The patients were randomized to undergo McCall’s culdoplasty (Group A) or sacrospinous ligament fixation (Group B) with vaginal hysterectomy based on note contained in an envelope comparative analysis was done, and patients were evaluated for intra-operative difficulties and immediate (48 hours) post-operative complications using SPSS-version 23 for statistical analysis. The patients were followed up at one month and one year to evaluate symptomatically and objectively.Results: In group A, patients with 3-degree prolapse 1 woman had hemorrhage and 1 woman had bladder injury intraoperatively. Whereas in group B, 5 women had hemorrhage and 1 woman had rectal injury intraoperatively. All complications were dealt successfully. No other major intra- and post-operative complications occurred.Conclusions: Vaginal hysterectomy with sacrospinous colpopexy resulted in better outcomes after surgery. Hence, it was concluded that unilateral or bilateral SSLF may be added to vaginal hysterectomy in patients of stage 3 or 4 prolapse

Use of a onedimensional link-node model to develop total maximum daily load strategies for the San Joaquin River Estuary

A one-dimensional link-node model was used to simulate water quality conditions in the tidallyinfluenced, deep water ship channel (DWSC) of the San Joaquin River located in Central California. The DWSC has been plagued with low dissolved oxygen (DO) conditions for decades and is currently a focus of restoration efforts. The model was calibrated using a six-year flow and water quality data set. Model simulations were run by removing the mass loads of each of the following major sources of oxygen depletion to determine the effects: elimination of the deepened ship channel (i.e., restore to its preexisting depth), elimination of import of oxygen-demanding substances (ODS) from the San Joaquin River watershed, elimination of import of ODS from the urban tributaries, and elimination of discharge of ODS from the City of Stockton regional wastewater control facility. The model results suggest that elimination of the deepened ship channel resulted in the best projected improvement relative to the modelled baseline with a predicted 55% improvement, while reducing ODS from the watershed would likely cause a 44% improvement. These results demonstrate that there are multiple contributing factors causing low DO in the DWSC and that removal or elimination of any single variable will not result in a complete resolution of low DO events

Use of the WARMF Model to Identify Sources of Oxygen Impairment and Potential Management Strategies for the San Joaquin River Watershed

Eutrophication of the San Joaquin River (SJR) has resulted in low dissolved oxygen (DO) conditions, which has led to a regulatory response and development of total maximum daily load (TMDL) allocations. Due to the dynamic nature of processes governing oxygen depletion in the SJR, a model was needed to help stakeholders understand the fate and transport of nutrients and oxygendemanding substances that cause the low DO conditions. Here, the Watershed Analysis Risk Management Framework (WARMF) model was used to simulate nutrient removal and control strategies, accounting for the secondary effects of growth and transformation between sources and discharge. Using the management alternatives in the WARMF Consensus Module, simulations were run to test the global removal of nutrient inputs on downstream phytoplankton growth, a major contributor of oxygen demand in the SJR. In the simulations, removal of ammonia had the greatest impact on downstream phytoplankton, causing a 32% reduction, while removal of phosphate and nitrate caused reductions of 25% and 13%, respectively. When ammonia and nitrate were both removed, phytoplankton reduction was 62%. These model results suggest that nitrogen control programs would be more effective than phosphorus programs. Using the Data Module in WARMF, input files were modified to determine the impacts of individual tributaries and agricultural drainages. In each simulation, the contributing loads for individual inputs were removed while maintaining flow. According to the model output, the largest impact on phytoplankton occurred with the removal of mass loads from Salt Slough (32% less than baseline). The effect of removing the mass loads from Mud Slough had a slightly lower impact (26% less than baseline). The WARMF model proved useful for exploration of planning and management alternatives, providing an expert decision-making tool that is available to stakeholders