Field notes on stapeliae collected in the Laikipia-Samburu district of Kenya

Volume: XI

Permeability of Two Parachute Fabrics - Measurements, Modeling, and Application

Two parachute fabrics, described by Parachute Industry Specifications PIA-C-7020D Type I and PIA-C-44378D Type I, were tested to obtain their permeabilities in air (i.e., flow-through volume of air per area per time) over the range of differential pressures from 0.146 psf (7 Pa) to 25 psf (1197 Pa). Both fabrics met their specification permeabilities at the standard differential pressure of 0.5 inch of water (2.60 psf, 124 Pa). The permeability results were transformed into an effective porosity for use in calculations related to parachutes. Models were created that related the effective porosity to the unit Reynolds number for each of the fabrics. As an application example, these models were used to calculate the total porosities for two geometrically-equivalent subscale Disk-Gap-Band (DGB) parachutes fabricated from each of the two fabrics, and tested at the same operating conditions in a wind tunnel. Using the calculated total porosities and the results of the wind tunnel tests, the drag coefficient of a geometrically-equivalent full-scale DGB operating on Mars was estimated

The ral exchange factor rgl2 promotes cardiomyocyte survival and inhibits cardiac fibrosis

Cardiomyocytes compensate to acute cardiac stress by increasing in size and contractile function. However, prolonged stress leads to a decompensated response characterized by cardiomyocyte death, tissue fibrosis and loss of cardiac function. Identifying approaches to inhibit this transition to a decompensated response may reveal important targets for treating heart failure. The Ral guanine nucleotide disassociation (RalGDS) proteins are Ras-interacting proteins that are upregulated by hypertrophic stimuli. The Ral guanine nucleotide dissociation stimulator-like 2 (Rgl2) is a member of the RalGDS family that modulates expression of hypertrophic genes in cardiomyocytes. However, the pathophysiologic consequence of increased Rgl2 expression in cardiomyoctyes remains unclear. To evaluate the effect of increasing Rgl2 activity in the heart, transgenic mice with cardiac-targeted over-expression of Rgl2 were generated. Although Ral activation was increased, there were no apparent morphologic or histological differences between the hearts of Rgl2 transgenic and nontransgenic mice indicating that increased Rgl2 expression had no effect on basal cardiac phenotype. To determine if Rgl2 modulates the cardiac response to stress, mice were infused with the ß-adrenergic receptor agonist, isoproterenol. Isoproterenol infusion increased heart mass in both Rgl2 transgenic and nontransgenic mice. However, unlike nontransgenic mice, Rgl2 transgenic mice showed no morphologic evidence of cardiomyocyte damage or increased cardiac fibrosis following isoproterenol infusion. Increased Rgl2 expression in cultured cardiomyocytes stimulated Ral activation and inhibited staurosporine-induced apoptosis via increased activation of PI3-kinase. Activation of the PI3-kinase signaling pathway was confirmed in hearts isolated from Rgl2 transgenic mice. Increased expression and function of Rgl2 in cardiomyocytes promotes activation of the PI3-kinase signaling cascade and protects from carciomyocyte death and pathologic cardiac fibrosis. Taken further, these results suggest that Rgl2 upregulation in hypertrophic hearts may be a protetive mechanism, and that Rgl2 may be a novel therapeutic target in treating heart disease

Comment on ``Conduction states in oxide perovskites: Three manifestations of Ti3+^{3 +} Jahn-Teller polarons in barium titanate''

In this comment to [S. Lenjer, O. F. Schirmer, H. Hesse, and Th. W. Kool, Phys. Rev. B {\bf 66}, 165106 (2002)] we discuss the electronic structure of oxygen vacancies in perovskites. First principles computations are in favour of rather deep levels in these vacancies, and Lenjer et al suggest that the electrons' interaction energy is negative, but data on electroconductivity are against.Comment: 2 pages, no figure

Controlling TcT_c of Iridium films using interfacial proximity effects

High precision calorimetry using superconducting transition edge sensors requires the use of superconducting films with a suitable $T_c$, depending on the application. To advance high-precision macrocalorimetry, we require low-$T_c$ films that are easy to fabricate. A simple and effective way to suppress $T_c$ of superconducting Iridium through the proximity effect is demonstrated by using Ir/Pt bilayers as well as Au/Ir/Au trilayers. While Ir/Au films fabricated by applying heat to the substrate during Ir deposition have been used in the past for superconducting sensors, we present results of $T_c$ suppression on Iridium by deposition at room temperature in Au/Ir/Au trilayers and Ir/Pt bilayers in the range of $\sim$20-100~mK. Measurements of the relative impedance between the Ir/Pt bilayers and Au/Ir/Au trilayers fabricated show factor of $\sim$10 higher values in the Ir/Pt case. These new films could play a key role in the development of scalable superconducting transition edge sensors that require low-$T_c$ films to minimize heat capacity and maximize energy resolution, while keeping high-yield fabrication methods.Comment: 5 journal pages, 4 figure

Masked volume wise principal component analysis of small adrenocortical tumours in dynamic [11C]-metomidate positron emission tomography

<p>Abstract</p> <p>Background</p> <p>In previous clinical Positron Emission Tomography (PET) studies novel approaches for application of Principal Component Analysis (PCA) on dynamic PET images such as Masked Volume Wise PCA (MVW-PCA) have been introduced. MVW-PCA was shown to be a feasible multivariate analysis technique, which, without modeling assumptions, could extract and separate organs and tissues with different kinetic behaviors into different principal components (MVW-PCs) and improve the image quality.</p> <p>Methods</p> <p>In this study, MVW-PCA was applied to 14 dynamic 11C-metomidate-PET (MTO-PET) examinations of 7 patients with small adrenocortical tumours. MTO-PET was performed before and 3 days after starting per oral cortisone treatment. The whole dataset, reconstructed by filtered back projection (FBP) 0–45 minutes after the tracer injection, was used to study the tracer pharmacokinetics.</p> <p>Results</p> <p>Early, intermediate and late pharmacokinetic phases could be isolated in this manner. The MVW-PC1 images correlated well to the conventionally summed image data (15–45 minutes) but the image noise in the former was considerably lower. PET measurements performed by defining "hot spot" regions of interest (ROIs) comprising 4 contiguous pixels with the highest radioactivity concentration showed a trend towards higher SUVs when the ROIs were outlined in the MVW-PC1 component than in the summed images. Time activity curves derived from "50% cut-off" ROIs based on an isocontour function whereby the pixels with SUVs between 50 to 100% of the highest radioactivity concentration were delineated, showed a significant decrease of the SUVs in normal adrenal glands and in adrenocortical adenomas after cortisone treatment.</p> <p>Conclusion</p> <p>In addition to the clear decrease in image noise and the improved contrast between different structures with MVW-PCA, the results indicate that the definition of ROIs may be more accurate and precise in MVW-PC1 images than in conventional summed images. This might improve the precision of PET measurements, for instance in therapy monitoring as well as for delineation of the tumour in radiation therapy planning.</p

Modeling the transboundary risk of feed ingredients contaminated with porcine epidemic diarrhea virus

Citation: Dee, S., Neill, C., Singrey, A., Clement, T., Cochrane, R., Jones, C., . . . Nelson, E. (2016). Modeling the transboundary risk of feed ingredients contaminated with porcine epidemic diarrhea virus. Bmc Veterinary Research, 12, 12. doi:10.1186/s12917-016-0674-zBackground: This study describes a model developed to evaluate the transboundary risk of PEDV-contaminated swine feed ingredients and the effect of two mitigation strategies during a simulated transport event from China to the US. Results: Ingredients imported to the USA from China, including organic & conventional soybeans and meal, lysine hydrochloride, D-L methionine, tryptophan, Vitamins A, D & E, choline, carriers (rice hulls, corn cobs) and feed grade tetracycline, were inoculated with PEDV. Control ingredients, and treatments (ingredients plus a liquid antimicrobial (SalCURB, Kemin Industries (LA) or a 2 % custom medium chain fatty acid blend (MCFA)) were tested. The model ran for 37 days, simulating transport of cargo from Beijing, China to Des Moines, IA, US from December 23, 2012 to January 28, 2013. To mimic conditions on land and sea, historical temperature and percent relative humidity (% RH) data were programmed into an environmental chamber which stored all containers. To evaluate PEDV viability over time, ingredients were organized into 1 of 4 batches of samples, each batch representing a specific segment of transport. Batch 1 (segment 1) simulated transport of contaminated ingredients from manufacturing plants in Beijing (day 1 post-contamination (PC)). Batch 2 (segments 1 and 2) simulated manufacturing and delivery to Shanghai, including time in Anquing terminal awaiting shipment (days 1-8 PC). Batch 3 (segments 1, 2 and 3) represented time in China, the crossing of the Pacific and entry to the US at the San Francisco, CA terminal (day 1-27 PC). Batch 4 (segments 1-4) represented the previous events, including transport to Des Moines, IA (days 1-37 PC). Across control (non-treated) ingredients, viable PEDV was detected in soybean meal (organic and conventional), Vitamin D, lysine hydrochloride and choline chloride. In contrast, viable PEDV was not detected in any samples treated with LA or MCFA. Conclusions: These results demonstrate the ability of PEDV to survive in a subset of feed ingredients using a model simulating shipment from China to the US. This is proof of concept suggesting that contaminated feed ingredients could serve as transboundary risk factors for PEDV, along with the identification of effective mitigation options

Quasi-Quantum Groups, Knots, Three-Manifolds, and Topological Field Theory

We show how to construct, starting from a quasi-Hopf algebra, or quasi-quantum group, invariants of knots and links. In some cases, these invariants give rise to invariants of the three-manifolds obtained by surgery along these links. This happens for a finite-dimensional quasi-quantum group, whose definition involves a finite group $G$, and a 3-cocycle \om, which was first studied by Dijkgraaf, Pasquier and Roche. We treat this example in more detail, and argue that in this case the invariants agree with the partition function of the topological field theory of Dijkgraaf and Witten depending on the same data G, \,\om.Comment: 30 page