Understanding local forces in electrophoretic ink systems: utilizing optical tweezers to explore electrophoretic display devices

Optical tweezers can be used as a valuable tool to characterize electrophoretic display (EPD) systems. EPDs are ubiquitous with e-readers and are becoming a commonplace technology where reflective, low-power displays are required; yet the physics of some features crucial to their operation remains poorly defined. We utilize optical tweezers as a tool to understand the motion of charged ink particles within the devices and show that the response of optically trapped electrophoretic particles can be used to characterize electric fields within these devices. This technique for mapping the force can be compared to simulations of the electric field in our devices, thus demonstrating that the electric field itself is the sole governor of the particle motion in an individual-particle regime. By studying the individual-particle response to the electric field, we can then begin to characterize particle motion in ‘real’ systems with many particles. Combining optical tweezing with particle tracking techniques, we can investigate deviations in many particle systems from the single-particle case

Holistic obstetrics and gynaecology mind maps teaching an easy-to-use tool provides equality of learning, teaching, and assessment

Aim: A pilot study was conducted to evaluate the learning benefits of holistic Obstetrics and Gynaecology mind maps (HOGMMs) in acquiring a range of clinical skills, standardizing assessment, and teaching methods. Methodology: HOGMMs were developed and had been used as a teaching tool for Year 3 medical students (n=113) for 6 months in between January and July 2016 as a tool to assist their learning during their Obstetrics and Gynaecology (OG) rotation. The HOGMMs were taught to all Year 3 medical students and a soft copy of the tool was shared with them as a reference for their use during their clinical placement in OG rotation. After the completion of their OG rotation, students were invited to complete a questionnaire assessing perceived benefits for skill acquisition, and standardizing assessment and teaching methods. Results: The majority of students believed HOGMMs was a useful learning tool across a range of parameters (min = 59%; n = 96). Students who believed HOGMMs to be useful for standardising assessment were more likely to report mutual benefits in terms of student learning (χ2=35.836; P=0.0005) and standardising teaching methods (χ2=20.256; P =0.0005). Conclusion: This study suggests that students’ value our HOGMM’s not only for developing clinical skills but also standardising assessment and teaching methods

Electrochemical inhibition biosensor array for rapid detection of water pollutions based on bacteria immobilized on screen-printed gold electrodes

This work reports on the development of a bacteria-based inhibition biosensor array for detection of different types of pollutions, i.e. heavy metal ions (Zn 2+ ), pesticides (DDVP) and petro-chemicals (pentane), in water. The biosensor chip for preliminary identification of the above water pollutants is based on three types of bacteria (Escherichia coli, Shewanella oneidensis and Methylosinus trichosporium OB3b) immobilized on screen-printed gold electrode surface via poly L-lysine which provides strong adhesion of bacterial monolayer to the electrode without losses of biological function. A series of optical measurements and DC electrochemical measurements were carried out on these three types of bacteria species immobilized on modified screen printed gold electrodes as well as on the bacteria in solution samples. The principle of electrochemical detection of pollutants is based on the facts that live bacteria adsorbed (or immobilized) on the electrode surface appeared to be insulating and thus reducing the electrochemical current, while the bacteria damaged by pollutants are less insulating. The results obtained demonstrated different effects of the three different types of analytes studied, e.g. Zn 2+ , DDVP, and pentane, on the three bacteria used. The findings are encouraging for application of a pattern recognition approach for identification pollutants which may lead to development of a novel, simple, and cost-effective bio-sensing array for preliminary detection of environmental pollutants in water

Bench-to-bedside review : targeting antioxidants to mitochondria in sepsis

Peer reviewedPublisher PD

An invisibility cloak using silver nanowires

In this paper, we use the parameter retrieval method together with an analytical effective medium approach to design a well-performed invisible cloak, which is based on an empirical revised version of the reduced cloak. The designed cloak can be implemented by silver nanowires with elliptical cross-sections embedded in a polymethyl methacrylate host. This cloak is numerically proved to be robust for both the inner hidden object as well as incoming detecting waves, and is much simpler thus easier to manufacture when compared with the earlier proposed one [Nat. Photon. 1, 224 (2007)].Comment: 7 pages, 4 figures, 2 table

Quinupristin/dalfopristin in Staphylococcus aureus endophthalmitis: a case report

<p>Abstract</p> <p>Introduction</p> <p>The intravitreal injection of antibiotics remains the mainstay of therapy for postoperative endophthalmitis. Bacterial resistance, however, is still a pitfall in achieving an adequate response to treatment. Quinupristin/dalfopristin might be a feasible therapeutic option in these cases.</p> <p>Case presentation</p> <p>A 55-year-old Hispanic man had endophthalmitis secondary to <it>Staphylococcus aureus </it>in his right eye and was treated with intravitreal 0.4 mg/0.1 ml quinupristin/dalfopristin injection. Inflammation and pain remission were observed at four days after injection. The final best-corrected visual acuity was 20/40.</p> <p>Conclusion</p> <p>Although vancomycin remains the first-line intravitreal antibiotic therapy against infectious endophthalmitis caused by Gram-positive bacteria, quinupristin/dalfopristin exhibits similar efficacy and is theoretically more active against vancomycin-resistant strains, with no apparent retinal toxicity.</p

Cation complexation by mucoid Pseudomonas aeruginosa extracellular polysaccharide

Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung colonizer, producing an extracellular matrix (ECM) composed predominantly of the extracellular polysaccharide (EPS) alginate. The ECM limits antimicrobial penetration and, consequently, CF sufferers are prone to chronic mucoid P. aeruginosa lung infections. Interactions between cations with elevated concentrations in the CF lung and the anionic EPS, enhance the structural rigidity of the biofilm and exacerbates virulence. In this work, two large mucoid P. aeruginosa EPS models, based on β-D-mannuronate (M) and β-D-mannuronate-α-L-guluronate systems (M-G), and encompassing thermodynamically stable acetylation configurations–a structural motif unique to mucoid P. aeruginosa–were created. Using highly accurate first principles calculations, stable coordination environments adopted by the cations have been identified and thermodynamic stability quantified. These models show the weak cross-linking capability of Na+ and Mg2+ ions relative to Ca2+ ions and indicate a preference for cation binding within M-G blocks due to the smaller torsional rearrangements needed to reveal stable binding sites. The geometry of the chelation site influences the stability of the resulting complexes more than electrostatic interactions, and the results show nuanced chemical insight into previous experimental observations