Efficiency of 2D Photonic Crystal Emitters in Thermophotovoltaic Systems

Thermophotovoltaic (TPV) systems have the potential to convert energy in a very efficient way by using 2D photonic crystal (PhC) emitters. Recent advancements in TPV technology have developed many methods for effectively generating power. These recent advancements propose that emitters can suppress low energy photon emissions while increasing higher energy photon emissions. This can be achieved by utilising new 2D photonic crystal (PhC) structures on the surface of the emitter with varying diameter and shape.In this meta study we consider the multiple design fabrications of photonic crystal emitters and compare the efficiencies, power densities, and their potential use for converting different wavelengths into heat and power. This is done by analysing the thermodynamic factors present in the system that could potentially reduce the efficiency, and therefore power generation, of the thermophotovoltaic cell. This study found that certain shapes and materials can impact on the PhC structure and its ability to emit energy.

Investigation of the Safety of Focused Ultrasound-Induced Blood-Brain Barrier Opening in a Natural Canine Model of Aging

Rationale: Ultrasound-mediated opening of the Blood-Brain Barrier(BBB) has shown exciting potential for the treatment of Alzheimer\u27s disease(AD). Studies in transgenic mouse models have shown that this approach can reduce plaque pathology and improve spatial memory. Before clinical translation can occur the safety of the method needs to be tested in a larger brain that allows lower frequencies be used to treat larger tissue volumes, simulating clinical situations. Here we investigate the safety of opening the BBB in half of the brain in a large aged animal model with naturally occurring amyloid deposits. Methods: Aged dogs naturally accumulate plaques and show associated cognitive declines. Low-frequency ultrasound was used to open the BBB unilaterally in aged beagles (9-11yrs, n=10) in accordance with institutionally approved protocols. Animals received either a single treatment or four weekly treatments. Magnetic resonance imaging(MRI) was used to guide the treatments and assess the tissue effects. The animals underwent neurological testing during treatment follow-up, and a follow-up MRI exam 1 week following the final treatment. Results: The permeability of the BBB was successfully increased in all animals (mean enhancement: 19±11% relative to untreated hemisphere). There was a single adverse event in the chronic treatment group that resolved within 24 hrs. Follow-up MRI showed the BBB to be intact with no evidence of tissue damage in all animals. Histological analysis showed comparable levels of microhemorrhage between the treated and control hemispheres in the prefrontal cortex (single/repeat treatment: 1.0±1.4 vs 0.4±0.5/5.2±1.8 vs. 4.0±2.0). No significant differences were observed in beta-amyloid load (single/repeat: p=0.31/p=0.98) although 3/5 animals in each group showed lower Aβ loads in the treated hemisphere. Conclusion: Whole-hemisphere opening of the BBB was well tolerated in the aged large animal brain. The treatment volumes and frequencies used are clinically relevant and indicate safety for clinical translation. Further study is warranted to determine if FUS has positive effects on naturally occurring amyloid pathology

Gene expression changes linked to antimicrobial resistance, oxidative stress, iron depletion and retained motility are observed when Burkholderia cenocepacia grows in cystic fibrosis sputum

<p>Abstract</p> <p>Background</p> <p>Bacteria from the <it>Burkholderia cepacia </it>complex (Bcc) are the only group of cystic fibrosis (CF) respiratory pathogens that may cause death by an invasive infection known as cepacia syndrome. Their large genome (> 7000 genes) and multiple pathways encoding the same putative functions make virulence factor identification difficult in these bacteria.</p> <p>Methods</p> <p>A novel microarray was designed to the genome of <it>Burkholderia cenocepacia </it>J2315 and transcriptomics used to identify genes that were differentially regulated when the pathogen was grown in a CF sputum-based infection model. Sputum samples from CF individuals infected with the same <it>B. cenocepacia </it>strain as genome isolate were used, hence, other than a dilution into a minimal growth medium (used as the control condition), no further treatment of the sputum was carried out.</p> <p>Results</p> <p>A total of 723 coding sequences were significantly altered, with 287 upregulated and 436 downregulated; the microarray-observed expression was validated by quantitative PCR on five selected genes. <it>B. cenocepacia </it>genes with putative functions in antimicrobial resistance, iron uptake, protection against reactive oxygen and nitrogen species, secretion and motility were among the most altered in sputum. Novel upregulated genes included: a transmembrane ferric reductase (BCAL0270) implicated in iron metabolism, a novel protease (BCAL0849) that may play a role in host tissue destruction, an organic hydroperoxide resistance gene (BCAM2753), an oxidoreductase (BCAL1107) and a nitrite/sulfite reductase (BCAM1676) that may play roles in resistance to the host defenses. The assumptions of growth under iron-depletion and oxidative stress formulated from the microarray data were tested and confirmed by independent growth of <it>B. cenocepacia </it>under each respective environmental condition.</p> <p>Conclusion</p> <p>Overall, our first full transcriptomic analysis of <it>B. cenocepacia </it>demonstrated the pathogen alters expression of over 10% of the 7176 genes within its genome when it grows in CF sputum. Novel genetic pathways involved in responses to antimicrobial resistance, oxidative stress, and iron metabolism were revealed by the microarray analysis. Virulence factors such as the cable pilus and Cenocepacia Pathogenicity Island were unaltered in expression. However, <it>B. cenocepacia </it>sustained or increased expression of motility-associated genes in sputum, maintaining a potentially invasive phenotype associated with cepacia syndrome.</p

Right to Serve, Right to Lead: Lives and Legacies of the USCT

This is a catalog for an exhibit that follows the evolution of African-American participation in the Civil War, from slaves, to contrabands, to soldiers of the United States Colored Troops (USCT), as well as the lives of black veterans beyond the war, and their ultimate military and social legacy. Using a variety of period items, it creates a narrative that stretches from the Antebellum Period to the current day. In doing so, the exhibit shows how black sacrifice on the battlefield redefined the war\u27s purpose throughout the divided nation, how Jim Crowe suppressed the memory of black participation after Reconstruction, and how the illustrious African-American military tradition left by the USCT endures to this day in their modern heirs

Barium sulfate crystallization in non-aqueous solvent

Crystallisation is performed in a non-aqueous solvent, dimethylsulfoxide (DMSO), in order to determine what the role of water is on the crystallisation pathway. In both water and DMSO environments the particles do not appear to grow by ion addition but rather appear to grow through aggregation. The main difference in water is that the aggregation processes are not random and result in particle morphologies that bear relation to the single-crystal faces, suggesting an oriented attachment mechanism. In DMSO, the aggregation processes appear less oriented and while there is some lattice registry, lattice mismatch is also observed and the aggregate shape is spherical overall. This is confirmed in the 1200 cm−1infrared band shift to 1174 cm−1suggesting a strained solid is formed. It is observed that the solubility of barium sulfate in DMSO is higher than in water (presumably caused by a strong Ba2+O-S(CH3)2interaction), which explains the lower nucleation rates in DMSO compared to water at the same concentration. Intriguingly, there is a lower nucleation rate observed (even at a relatively high supersaturation) when Ba2+is solvated with DMSO supporting the hypothesis that de-solvation of the cation is the rate determining step in nucleation and is of higher activation energy in DMSO than in water