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Microchimerism (Mc), originating from bidirectional fetal–maternal cell traffic during pregnancy, has recently been identified in healthy adults and in patients with scleroderma (systemic sclerosis [SSc]). This study was undertaken to investigate the frequency and quantitative levels of maternal Mc (MMc) in healthy women and women with SSc. HLA-specific primers and fluorogenic probes were used in real-time quantitative polymerase chain reaction assays to detect and quantify MMc by targeting noninherited, nonshared HLA sequences. DNA-based HLA typing was conducted in 67 proband-mother pairs and in all children if the proband was parous. Statistical analysis was limited to 50 proband-mother pairs (including 32 healthy women and 18 women with SSc) in whom MMc could be distinguished from potential fetal Mc. MMc in peripheral blood mononuclear cells was more frequent among women with SSc (72%) than healthy women (22%) (odds ratio 9.3, P = 0.001). However, levels of MMc, expressed as the genome equivalent of maternal cells per million (gEq/mil), were not significantly different (0–68.6 gEq/mil in SSc patients, 0–54.5 in healthy women). In additional studies, positivity for MMc was demonstrated in a bone marrow aspirate from an SSc patient in whom peripheral blood had been found to be negative for MMc on 4 occasions, and tissue from a subsequent autopsy of this patient had MMc levels of 757 and 1,489 gEq/mil in the lung and heart, respectively. MMc is not uncommon in the peripheral blood of healthy adults, is increased in frequency in patients with SSc, and may be present in bone marrow and disease-affected tissues although absent in the peripheral blood. [ABSTRACT FROM AUTHOR]

The curvature of gas?liquid interfaces and the step change in properties across these interfaces in microchannels are shown here to create a powerful lens/mirror effect. In a hydrophilic system, light incident on the bubble is focused into the surrounding liquid, resulting in a locally increased total light exposure. The optical phenomena leading to this are discussed, and the effect is demonstrated experimentally by imaging the increased photobleaching rate of fluorophores in the near-bubble region. Numerical simulations of the system are performed to investigate the electrical potential and flow fields resulting from the application of an axial electric field. Microbubble lensing-induced photobleaching (µ-BLIP) is then applied as a method to inject a negative scalar flow marker for flow visualization in microchannels. Once formed, the electrokinetic transport of this marker is analyzed to determine the cross-channel velocity profile of the liquid phase and the liquid velocity in the film. Experimental data is verified by comparison with numerical predictions and previous experimental studies. This contribution represents both a new application of microscale gas?liquid interfacial phenomena, and a new technique for microfluidic flow visualization, particularly applicable (though not limited) to the study of multiphase microchannel flows. [ABSTRACT FROM AUTHOR]

Incorporating potential catastrophic consequences into integrated assessment models of climate change has been a top priority of policymakers and modelers alike. We review the current state of scientific understanding regarding three frequently mentioned geophysical catastrophes, with a view toward their implications for integrated assessment modeling. This review finds inadequacies in widespread model assumptions regarding the nature of catastrophes themselves and climate change impacts more generally. The possibility of greatly postponed consequences from near- and medium-term actions suggests that standard discounting practices are inappropriate for the analysis of climate catastrophe. Careful consideration of paleoclimate and geophysical modeling evidence regarding the possibility of changes in ocean circulation suggests a reframing of the source of climate change damages in economic models, placing changes in climate predictability, rather than gradual changes in mean values, at the focus of economic damage assessments. The implications of decreases in predictability for the modeling of adaptation are further discussed. [ABSTRACT FROM AUTHOR]

This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. [ABSTRACT FROM AUTHOR]

Quantum dot solar cells seek to surpass the solar energy conversion efficiencies achieved by bulk semiconductors. This new field requires a broad selection of materials to achieve its full potential. The 12 nm spherical protein ferritin can be used as a template for uniform and controlled nanocrystal growth, and to then house the nanocrystals for use in solar energy conversion. In this study, precise band gaps of titanium, cobalt, and manganese oxyhydroxide nanocrystals within ferritin were measured, and a change in band gap due to quantum confinement effects was observed. The range of band gaps obtainable from these three types of nanocrystals is 2.19–2.29 eV, 1.93–2.15 eV, and 1.60–1.65 eV respectively. From these measured band gaps, theoretical efficiency limits for a multi-junction solar cell using these ferritin-enclosed nanocrystals are calculated and found to be 38.0% for unconcentrated sunlight and 44.9% for maximally concentrated sunlight. If a ferritin-based nanocrystal with a band gap similar to silicon can be found (i.e. 1.12 eV), the theoretical efficiency limits are raised to 51.3% and 63.1%, respectively. For a current matched cell, these latter efficiencies become 41.6% (with an operating voltage of 5.49 V), and 50.0% (with an operating voltage of 6.59 V), for unconcentrated and maximally concentrated sunlight respectively. [ABSTRACT FROM AUTHOR]

The use of silicon photonic devices for optical manipulation has recently enabled the direct handling of objects like nucleic acids and nanoparticles that are much smaller than could previously be trapped using traditional laser tweezers. The ability to manipulate even smaller matter however requires the development of photonic structures with even stronger trapping potentials. In this work we investigate theoretically several photonic crystal resonator designs and characterize the achievable trapping stiffness and trapping potential depth (sometimes referred to as the trapping stability). Two effects are shown to increase these trapping parameters: field enhancement in the resonator and strong field containment. We find trapping stiffness as high as 22.3 pN nm [?] 1 for 100 nm polystyrene beads as well as potential depth of 51 000 kBT at T = 300 K, for one Watt of power input to the bus waveguide. Under the same conditions for 70 nm polystyrene beads, we find a stiffness of 69 pN nm [?] 1 and a potential depth of 177 000 kBT. Our calculations suggest that with input power of 10 mW we could trap particles as small as 7.7 nm diameter with a trapping depth of 500 kBT. We expect these traps to eventually enable the manipulation of small matter such as single proteins, carbon nanotubes and metallic nanoparticles. [ABSTRACT FROM AUTHOR]