Deep Space Missions for Small Satellites

Small satellites, with masses well under 100 kg, can perform useful deep space science missions for costs similar to those of low earth orbit and geosynchronous smallsats. Space Explorations has identified several interesting missions for smallsats, with the objective of developing turnkey space-science packages which would have a cost to the customer of $10,000,000 and be operable by one or a few people. We have analyzed one mission, a Lunar Polar Photographic Orbiter, in great detail over the last year. We conclude that it is commercially and scientifically feasible to produce a small lunar satellite which is capable of doing extensive, high-resolution photography of the moon. The LPPO would photograph those portions of the moon which have never been observed, at resolutions of 30 m, and it would remap the entire far southern quadrant of the moon at 100 times the resolution of existing maps

Lack of homologous sequence-specific DNA methylation in response to stable dsRNA expression in mouse oocytes

Double-stranded RNA (dsRNA) induces sequence-specific mRNA degradation in most eukaryotic organisms via a conserved pathway known as RNA interference (RNAi). Post-transcriptional gene silencing by RNAi is also connected with transcriptional silencing of cognate sequences. In plants, this transcriptional silencing is associated with sequence-specific DNA methylation. To address whether this mechanism operates in mammalian cells, we used bisulfite sequencing to analyze DNA in mouse oocytes constitutively expressing long dsRNA against the Mos gene. Our data show that long dsRNA induces efficient Mos mRNA knockdown but not CpG and non-CpG DNA methylation of the endogenous Mos sequence in oocytes and early embryos. These data demonstrate that dsRNA does not directly induce DNA methylation in the trans form of this sequence in these mammalian cell

A conserved circadian function for the Neurofibromatosis 1 gene

Summary: Loss of the Neurofibromatosis 1 (Nf1) protein, neurofibromin, in Drosophila disrupts circadian rhythms of locomotor activity without impairing central clock function, suggesting effects downstream of the clock. However, the relevant cellular mechanisms are not known. Leveraging the discovery of output circuits for locomotor rhythms, we dissected cellular actions of neurofibromin in recently identified substrates. Herein, we show that neurofibromin affects the levels and cycling of calcium in multiple circadian peptidergic neurons. A prominent site of action is the pars intercerebralis (PI), the fly equivalent of the hypothalamus, with cell-autonomous effects of Nf1 in PI cells that secrete DH44. Nf1 interacts genetically with peptide signaling to affect circadian behavior. We extended these studies to mammals to demonstrate that mouse astrocytes exhibit a 24-hr rhythm of calcium levels, which is also attenuated by lack of neurofibromin. These findings establish a conserved role for neurofibromin in intracellular signaling rhythms within the nervous system. : Bai et al. show that the gene mutated in the disease Neurofibromatosis 1 is required for maintaining levels or cycling of calcium in circadian neurons in Drosophila and in mammalian cells. These effects likely account for effects of Nf1 on circadian behavior in Drosophila and may be relevant in explaining sleep phenotypes in patients. Keywords: circadian rhythms, neurofibromatosis 1, Drosophila, peptide signaling, cycling of calcium, mouse astrocyte

Genetic variation and cognitive dysfunction in opioid-treated patients with cancer

Background and purpose The effects of single‐nucleotide polymorphisms (SNP s) on the cognitive function of opioid‐treated patients with cancer until now have not been explored, but they could potentially be related to poor functioning. This study aimed at identifying associations between SNP s of candidate genes, high opioid dose, and cognitive dysfunction. Methods Cross‐sectional multicenter study (European Pharmacogenetic Opioid Study, 2005–2008); 1586 patients; 113 SNP s from 41 genes. Inclusion criteria: cancer, age ≥18 year, opioid treatment, and available genetic data. Cognitive assessment by Mini‐Mental State Examination (MMSE ). Analyses: SNP s were rejected if violation of Hardy–Weinberg equilibrium (P < 0.0005), or minor allele frequency <5%; patients were randomly divided into discovery sample (2/3 for screening) and validation sample (1/3 for confirmatory test); false discovery rate of 10% for determining associations (Benjamini–Hochberg method). Co‐dominant, dominant, and recessive models were analyzed by Kruskal–Wallis and Mann–Whitney tests. Results In the co‐dominant model significant associations (P < 0.05) between MMSE scores and SNP s in the HTR 3E , TACR 1 , and IL 6 were observed in the discovery sample, but the replication in the validation sample did not confirm it. Associations between MMSE scores among patients receiving ≥400 mg morphine equivalent dose/day and SNP s in TNFRSF 1B , TLR 5 , HTR 2A , and ADRA 2A were observed, but they could not be confirmed in the validation sample. After correction for multiple testing, no SNP s were significant in the discovery sample. Dominant and recessive models also did not confirm significant associations. Conclusions The findings did not support influence of those SNP s analyzed to explain cognitive dysfunction in opioid‐treated patients with cancer

Recruitment of Orc6l, a dormant maternal mRNA in mouse oocytes, is essential for DNA replication in 1-cell embryos

Mouse oocytes acquire the ability to replicate DNA during meiotic maturation, presumably to ensure that DNA replication does not occur precociously between MI and MII and only after fertilization. Acquisition of DNA replication competence requires protein synthesis, but the identity of the proteins required for DNA replication is poorly described. In Xenopus, the only component missing for DNA replication competence is CDC6, which is synthesized from a dormant maternal mRNA recruited during oocyte maturation, and a similar situation also occurs during mouse oocyte maturation. We report that ORC6L is another component required for acquisition of DNA replication competence that is absent in mouse oocytes. The dormant maternal Orc6l mRNA is recruited during maturation via a CPE present in its 3␣ UTR. RNAi-mediated ablation of maternal Orc6l mRNA prevents the maturation-associated increase in ORC6L protein and inhibits DNA replication in 1-cell embryos. These results suggest that mammalian oocytes have more complex mecha- nisms to establish DNA replication competence when compared to their Xenopus counterparts.Fil: Murai, Shin. State University Of Pennsylvania; Estados UnidosFil: Stein, Paula. University of Pennsylvania; Estados UnidosFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina; Argentina. University of Pennsylvania; Estados UnidosFil: Yamashita, Shigeru. Toho University. School of Medicine; JapónFil: Schultz, Richard M.. University of Pennsylvania; Estados Unido

The Deformable Mirror Demonstration Mission (DeMi) CubeSat: optomechanical design validation and laboratory calibration

Coronagraphs on future space telescopes will require precise wavefront correction to detect Earth-like exoplanets near their host stars. High-actuator count microelectromechanical system (MEMS) deformable mirrors provide wavefront control with low size, weight, and power. The Deformable Mirror Demonstration Mission (DeMi) payload will demonstrate a 140 actuator MEMS deformable mirror (DM) with \SI{5.5}{\micro\meter} maximum stroke. We present the flight optomechanical design, lab tests of the flight wavefront sensor and wavefront reconstructor, and simulations of closed-loop control of wavefront aberrations. We also present the compact flight DM controller, capable of driving up to 192 actuator channels at 0-250V with 14-bit resolution. Two embedded Raspberry Pi 3 compute modules are used for task management and wavefront reconstruction. The spacecraft is a 6U CubeSat (30 cm x 20 cm x 10 cm) and launch is planned for 2019.Comment: 15 pages, 10 figues. Presented at SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, US

Speed and grade increment during cardiopulmonary treadmill testing : impact on exercise prescription

Background: Maximal oxygen uptake (VO2max) and both first (VT1) and second (VT2) thresholds have been used as reference points for exercise prescription in different populations. Objective: We aimed to test the hypothesis that exercise prescription, based on VTs determined by treadmill cardiopulmonary exercise testing (CPET), is influenced by the rate of increase in treadmill workload. Methods: Nine healthy individuals underwent two CPETs, followed by two sessions of submaximal exercise, both in randomized order. For the “speed” protocol, there was an increment of 0.1 to 0.3 km.h-1 every 15s. The “grade” incremental protocol increased 1% every 30s and 0.1 km.h-1 every 45s. This was followed by submaximal exercise sessions lasting 40min at an intensity corresponding to heart rate (HR) between the VT1 and VT2. Results: The “speed” protocol resulted in higher VT1 (p = 0.01) and VT2 (p = 0.02) when compared to the “grade” incremental protocol, but there was no effect on VO2max. The target HR for the submaximal exercise sessions was higher in the “speed” protocol compared to the “grade” incremental protocol (p < 0.01) and remained stable during the two steady-state exercise sessions. Blood lactate remained stable during the submaximal exercise sessions, with higher values observed during the “speed” protocol than those “grade” incremental protocol (p < 0.01). Conclusions: Compared to a grade-based protocol, a speed-based protocol resulted in higher VT1 and VT2, which significantly affected cardiorespiratory and metabolic responses to prescribed exercise intensity in healthy young adults