Synthesis of water-soluble chiral DOTA lanthanide complexes with predominately twisted square antiprism isomers and circularly polarized luminescence emission

One-step cyclization of a tetraazamacrocycle 5 with 70% yield in a 25-g scale was performed. Its chiral DOTA derivatives, L4, has ∼93% of TSAP coordination isomer in its Eu(III) and Yb(III) complexes in aqueous solution. [GdL4]5– exhibits a high relaxivity, making it a promising and efficient MRI contrast agent. High luminescence dissymmetry factor (glum) values of 0.285 (ΔJ = 1) for [TbL3]– and 0.241 (ΔJ = 1) for [TbL4]5– in buffer solutions were recorded

Socialising Big Data: From concept to practice

The working paper is a report on an ESRC-fundedproject, Socialising Big Data, that sought to address problematic conceptions of Big Data in popular discourse such as the ‘data deluge’ and the tendency to reduce the term to definitions such as the oft-cited‘3 Vs’. Instead, building on how social scientists have conceived of things, methods and data as having social and cultural lives, the project sought to identify the normative, political and technical imperatives and choices that come to shape Big Data at various momentsin its social lives. Recognising that Big Data involves distributed practices across a range of fields, the project experimentedwith collaboratories as a method for bringing together and engaging with practitioners acrossthree different domains –genomics, national statistics and waste management. In this way it explored how relations between data are also simultaneously relations between people and that it is through such relations that a shared literacyand social framework for Big Datacan be forged

Impact of carbon nanotube length on electron transport in aligned carbon nanotube networks

Here, we quantify the electron transport properties of aligned carbon nanotube (CNT) networks as a function of the CNT length, where the electrical conductivities may be tuned by up to 10× with anisotropies exceeding 40%. Testing at elevated temperatures demonstrates that the aligned CNT networks have a negative temperature coefficient of resistance, and application of the fluctuation induced tunneling model leads to an activation energy of ≈14 meV for electron tunneling at the CNT-CNT junctions. Since the tunneling activation energy is shown to be independent of both CNT length and orientation, the variation in electron transport is attributed to the number of CNT-CNT junctions an electron must tunnel through during its percolated path, which is proportional to the morphology of the aligned CNT network.United States. Army Research Office (contract W911NF-07-D-0004)United States. Army Research Office (contract W911NF-13-D-0001)United States. Air Force Office of Scientific Research (AFRL/RX contract FA8650-11-D-5800, Task Order 0003)National Science Foundation (U.S.) (NSF Award No. ECS-0335765)United States. Dept. of Defense (National Defense Science and Engineering Graduate Fellowship

A multispectral microscope for in vivo oximetry of rat dorsal spinal cord vasculature

Quantification of blood oxygen saturation (SO2) in vivo is essential for understanding the pathogenesis of diseases in which hypoxia is thought to play a role, including inflammatory disorders such as multiple sclerosis (MS) and rheumatoid arthritis (RA). We describe a low-cost multispectral microscope and oximetry technique for calibration-free absolute oximetry of surgically exposed blood vessels in vivo. We imaged the vasculature of the dorsal spinal cord in healthy rats, and varied inspired oxygen (FiO2) in order to evaluate the sensitivity of the imaging system to changes in SO2. The venous SO2 was calculated as 67.8  ±  10.4% (average  ±  standard deviation), increasing to 83.1  ±  11.6% under hyperoxic conditions (100% FiO2) and returning to 67.4  ±  10.9% for a second normoxic period; the venous SO2 was 50.9  ±  15.5% and 29.2  ±  24.6% during subsequent hypoxic states (18% and 15% FiO2 respectively). We discuss the design and performance of our multispectral imaging system, and the future scope for extending this oximetry technique to quantification of hypoxia in inflamed tissue

Influence of polyvinylpyrrolidone (PVP) in the synthesis of luminescent NaYF4:Yb,Er upconversion nanoparticles

Polyvinylpyrrolidone (PVP) can be used to produce upconversion nanoparticles (UCNPs) in an advantageous manner, i.e. at modest temperatures in open-to-air conditions with simple hotplate and flask apparatus. However, the influence of PVP parameters on the formation of UCNPs has not been previously investigated. In this exploratory study, we establish that PVP molecular weight and relative amount of PVP can greatly influence the morphology and diameter of NaYF4:Yb,Er UCNPs produced via the PVP-assisted route. At nominal amounts of PVP, varying the molecular weight of PVP in synthesis between 10,000 g/mol (PVP10), 40,000 g/mol (PVP40), and 55,000 g/mol (PVP55), had minimal effect on UCNP morphology, whereas reducing the quantity of PVP10 and PVP40 in the reaction to 10% of the nominal amount resulted in two notable effects: (1) the generation of a greater range of UCNP diameters and (2) the production of an unexpected sub-population of rhombus-shaped UCNPs. Bulk and individual nanoparticle analysis indicates that all UCNP morphologies were cubic (α-phase) crystal structure and consisted of NaYF4:Yb,Er. Optical emission properties exhibited only modest green and red luminescence emission ratio when PVP parameters were varied. However, separately produced PVP40 NaYF4:Yb,Tm UCNPs exhibited a much more intense and dual-band blue /red emission. This exploratory work demonstrates that tailoring PVP content in synthesis of UCNPs can greatly alter morphology of UCNPs produced and should be carefully considered in experimental design. However, the underlying mechanisms of action of the role PVP plays in this synthesis remain unclear. Ultimately, significant further work is still required to fully elucidate the relevant chemistry to achieve full control of PVP-UCNP synthesis

Stroke Ready Intervention: Community Engagement to Decrease Prehospital Delay

Background: Time-limited acute stroke treatments are underused, primarily due to prehospital delay. One approach to decreasing prehospital delay is to increase stroke preparedness, the ability to recognize stroke, and the intention to immediately call emergency medical services, through community engagement with high-risk communities. Methods and Results: Our community-academic partnership developed and tested "Stroke Ready," a peer-led, workshop-based, health behavior intervention to increase stroke preparedness among African American youth and adults in Flint, Michigan. Outcomes were measured with a series of 9 stroke and nonstroke 1-minute video vignettes; after each video, participants selected their intended response (primary outcome) and symptom recognition (secondary outcome), receiving 1 point for each appropriate stroke response and recognition. We assessed differences between baseline and posttest appropriate stroke response, which was defined as intent to call 911 for stroke vignettes and not calling 911 for nonstroke, nonemergent vignettes and recognition of stroke. Outcomes assessments were performed before workshop 1 (baseline), at the conclusion of workshop 2 (immediate post-test), and 1 month later (delayed post-test). A total of 101 participants completed the baseline assessment (73 adults and 28 youths), 64 completed the immediate post-test, and 68 the delayed post-test. All participants were African American. The median age of adults was 56 (interquartile range 35-65) and of youth was 14 (interquartile range 11-16), 65% of adults were women, and 50% of youths were women. Compared to baseline, appropriate stroke response was improved in the immediate post-test (4.4 versus 5.2, P < 0.01) and was sustained in the delayed post-test (4.4 versus 5.2, P < 0.01). Stroke recognition did not change in the immediate post-test (5.9 versus 6.0, P=0.34), but increased in the delayed post-test (5.9 versus 6.2, P=0.04). Conclusions: Stroke Ready increased stroke preparedness, a necessary step toward increasing acute stroke treatment rates

Understanding Anthropological Understanding: for a merological anthropology

In this paper I argue for a merological anthropology in which ideas of ‘partiality’ and ‘practical adequacy’ provide a way out of the impasse of relativism which is implied by post-modernism and the related abandonment of a concern with ‘truth’. Ideas such as ‘aptness’ and ‘faithfulness’ enable us to re-establish empirical foundations without having to espouse a simple realism which has been rightly criticised. Ideas taken from ethnomethodology, particularly the way we bootstrap from ‘practical adequacy’ to ‘warrants for confidence’ point to a merological anthropology in which we recognize that we do not and cannot know everything, but that we can have reasons for being confident in the little we know

Synthesis and Structural Diversification of Circularly Polarised Luminescence Active, Helically Chiral, “Confused” N,N,O,C‐BODIPYs**

Helically chiral boron-chelated dipyrromethene (BODIPY) dyes are known to exhibit solution phase circularly polarized luminescence (CPL), but examples are limited to a few synthetically accessible molecular architectures. We report a B−N chelation, SNAr, Suzuki cross-coupling, B−O chelation cascade reaction for the synthesis of understudied helically chiral, N,N,O,C-boron chelated, “confused” BODIPYs, from readily accessible 3,5-dibromo-BODIPY starting materials. Using this approach we have prepared a series of helically chiral “confused” BODIPYs with variation of the 3,5-subsitutents. Following resolution by chiral HPLC, absolute stereochemistry was assigned through comparison of the experimental and calculated ECD spectra, and solution phase chiroptical properties including CPL were determined (|glum| from 2.1 to 3.7×10−3; BCPL from 11.3 to 27.2)