Methane and Nitrogen Abundances On Pluto and Eris

We present spectra of Eris from the MMT 6.5 meter telescope and Red Channel Spectrograph (5700-9800 angstroms; 5 angstroms per pix) on Mt. Hopkins, AZ, and of Pluto from the Steward Observatory 2.3 meter telescope and Boller and Chivens spectrograph (7100-9400 angstroms; 2 angstroms per pix) on Kitt Peak, AZ. In addition, we present laboratory transmission spectra of methane-nitrogen and methane-argon ice mixtures. By anchoring our analysis in methane and nitrogen solubilities in one another as expressed in the phase diagram of Prokhvatilov and Yantsevich (1983), and comparing methane bands in our Eris and Pluto spectra and methane bands in our laboratory spectra of methane and nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are about 10% and about 90%, and Pluto's bulk methane and nitrogen abundances are about 3% and about 97%. Such abundances for Pluto are consistent with values reported in the literature. It appears that the bulk volatile composition of Eris is similar to the bulk volatile composition of Pluto. Both objects appear to be dominated by nitrogen ice. Our analysis also suggests, unlike previous work reported in the literature, that the methane and nitrogen stoichiometry is constant with depth into the surface of Eris. Finally, we point out that our Eris spectrum is also consistent with a laboratory ice mixture consisting of 40% methane and 60% argon. Although we cannot rule out an argon rich surface, it seems more likely that nitrogen is the dominant species on Eris because the nitrogen ice 2.15 micron band is seen in spectra of Pluto and Triton.Comment: The manuscript has 44 pages, 15 figures, and four tables. It will appear in the Astrophysical Journa

Complications related to deep venous thrombosis prophylaxis in trauma: a systematic review of the literature

Deep venous thrombosis prophylaxis is essential to the appropriate management of multisystem trauma patients. Without thromboprophylaxis, the rate of venous thrombosis and subsequent pulmonary embolism is substantial. Three prophylactic modalities are common: pharmacologic anticoagulation, mechanical compression devices, and inferior vena cava filtration. A systematic review was completed using PRISMA guidelines to evaluate the potential complications of DVT prophylactic options. Level one evidence currently supports the use of low molecular weight heparins for thromboprophylaxis in the trauma patient. Unfortunately, multiple techniques are not infrequently required for complex multisystem trauma patients. Each modality has potential complications. The risks of heparin include bleeding and heparin induced thrombocytopenia. Mechanical compression devices can result in local soft tissue injury, bleeding and patient non-compliance. Inferior vena cava filters migrate, cause inferior vena cava occlusion, and penetrate the vessel wall. While the use of these techniques can be life saving, they must be appropriately utilized

Regulation of in vivo dynein force production by CDK5 and 14-3-3ε and KIAA0528.

Single-molecule cytoplasmic dynein function is well understood, but there are major gaps in mechanistic understanding of cellular dynein regulation. We reported a mode of dynein regulation, force adaptation, where lipid droplets adapt to opposition to motion by increasing the duration and magnitude of force production, and found LIS1 and NudEL to be essential. Adaptation reflects increasing NudEL-LIS1 utilization; here, we hypothesize that such increasing utilization reflects CDK5-mediated NudEL phosphorylation, which increases the dynein-NudEL interaction, and makes force adaptation possible. We report that CDK5, 14-3-3ε, and CDK5 cofactor KIAA0528 together promote NudEL phosphorylation and are essential for force adaptation. By studying the process in COS-1 cells lacking Tau, we avoid confounding neuronal effects of CDK5 on microtubules. Finally, we extend this in vivo regulatory pathway to lysosomes and mitochondria. Ultimately, we show that dynein force adaptation can control the severity of lysosomal tug-of-wars among other intracellular transport functions involving high force

High positive predictive value (PPV) of cell-free DNA (cfDNA) testing in a clinical study of 10,000 consecutive pregnancies

Background: Cell-free DNA (cfDNA) analysis in maternal blood for the detection of fetal Down syndrome is gradually replacing first trimester screening. We present here a large clinical series of 10,000 consecutive pregnancies. Objectives: To study the reliability of cell-free DNA (cfDNA) analysis in maternal blood for the detection of fetal trisomy 21, 18 and 13 in a clinical setting in 10,000 consecutive pregnancies with variable risk. cfDNA testing has been evaluated in an increasing number of pregnancies mainly at high risk for fetal trisomy, and some studies have suggested that its positive predictive value (PPV) might be lower in low-risk populations. Study design: CfDNA testing using the Harmony™ Prenatal Test was performed in 10,000 consecutive pregnancies with high or low a-priori risk for fetal trisomy 21, 18 and 13. Results: In 147 (1.47%) of the 10,000 pregnancies a high-risk cfDNA testing result indicated trisomy 21 (n=121), trisomy 18 (n=15) or trisomy 13 (n=11). It failed to detect 5 trisomies (2 trisomies 21, 2 trisomies 18, and 1 trisomy 13). Five false-positive results were recorded (4 in the high and 1 in the low risk population). The overall positive predictive value (PPV) was 96%, with a PPV of 96% in the high-risk (>1/200) population and 97% in the low risk (<1/200) population. Conclusions: In this large clinical series of 10,000 consecutive pregnancies, cfDNA testing proved very reliable in detecting fetal trisomy 21, 18 and 13, with a very high PPV both in high and low risk populations