Astrobee: A New Tool for ISS Operations

Astrobee is a new class of free-flying robots that operate in the interior of the International Space Station (ISS). In addition to providing a research platform for zero-g free-flying robotics (replacing the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES)), Astrobee improves the efficiency of ISS operations by providing flight and payload controllers with a mobile camera/sensor platform. The Astrobee system consists of three robots, a docking station, and a ground data system. Development began in late 2014, and Astrobee will launch to ISS in late 2018. This paper provides an overview of the capabilities of the Astrobee system, the concept of operations for ISS operations support, and the challenges of operating a free-flying robot within the constraints of the ISS environment

Measuring Fluorescent Dye in the Bubbly and Sediment-Laden Surfzone

Decisions about recreational beach closures would be enhanced if better estimates of surfzone contaminant transport and dilution were available. In situ methods for measuring fluorescent Rhodamine WT dye tracer in the surfzone are presented, increasing the temporal and spatial resolution over previous surfzone techniques. Bubbles and sand suspended by breaking waves in the surfzone interfere with in situ optical fluorometer dye measurements, increasing the lower bound for dye detection (≈ 1 ppb) and reducing (quenching) measured dye concentrations. Simultaneous turbidity measurements are used to estimate the level of bubble and sand interference and correct dye estimates. After correction, root-mean-square dye concentration errors are estimated to be < 5% of dye concentration magnitude, thus demonstrating the viability of in situ surfzone fluorescent dye measurements. The surfzone techniques developed here may be applicable to other environments with high bubble and sand concentrations (e.g., cascading rivers and streams)

Detailed deletion mapping of chromosome band 14q32 in human neuroblastoma defines a 1.1-Mb region of common allelic loss

Neuroblastoma (NB) is a well-known malignant disease in infants, but its molecular mechanisms have not yet been fully elucidated. To investigate the genetic contribution of abnormalities on the long arm of chromosome 14 (14q) in NB, we analysed loss of heterozygosity (LOH) in 54 primary NB samples using 12 microsatellite markers on 14q32. Seventeen (31%) of 54 tumours showed LOH at one or more of the markers analysed, and the smallest common region of allelic loss was identified between D14S62 and D14S987. This region was estimated to be 1-cM long from the linkage map. Fluorescence in situ hybridization also confirmed the loss. There was no statistical correlation between LOH and any clinicopathologic features, including age, stage, amplification of MYCN and ploidy. We further constructed a contig spanning the lost region using bacterial artificial chromosome and estimated this region to be approximately 1.1-Mb by pulsed-field gel electrophoresis. Our results will contribute to cloning and characterizing the putative tumour-associated gene(s) in 14q32 in NB. © 2000 Cancer Research Campaig

From bit to it: How a complex metabolic network transforms information into living matter

Organisms live and die by the amount of information they acquire about their environment. The systems analysis of complex metabolic networks allows us to ask how such information translates into fitness. A metabolic network transforms nutrients into biomass. The better it uses information on available nutrient availability, the faster it will allow a cell to divide. I here use metabolic flux balance analysis to show that the accuracy I (in bits) with which a yeast cell can sense a limiting nutrient's availability relates logarithmically to fitness as indicated by biomass yield and cell division rate. For microbes like yeast, natural selection can resolve fitness differences of genetic variants smaller than 10-6, meaning that cells would need to estimate nutrient concentrations to very high accuracy (greater than 22 bits) to ensure optimal growth. I argue that such accuracies are not achievable in practice. Natural selection may thus face fundamental limitations in maximizing the information processing capacity of cells. The analysis of metabolic networks opens a door to understanding cellular biology from a quantitative, information-theoretic perspective

Functional Diversity and Structural Disorder in the Human Ubiquitination Pathway

The ubiquitin-proteasome system plays a central role in cellular regulation and protein quality control (PQC). The system is built as a pyramid of increasing complexity, with two E1 (ubiquitin activating), few dozen E2 (ubiquitin conjugating) and several hundred E3 (ubiquitin ligase) enzymes. By collecting and analyzing E3 sequences from the KEGG BRITE database and literature, we assembled a coherent dataset of 563 human E3s and analyzed their various physical features. We found an increase in structural disorder of the system with multiple disorder predictors (IUPred - E1: 5.97%, E2: 17.74%, E3: 20.03%). E3s that can bind E2 and substrate simultaneously (single subunit E3, ssE3) have significantly higher disorder (22.98%) than E3s in which E2 binding (multi RING-finger, mRF, 0.62%), scaffolding (6.01%) and substrate binding (adaptor/substrate recognition subunits, 17.33%) functions are separated. In ssE3s, the disorder was localized in the substrate/adaptor binding domains, whereas the E2-binding RING/HECT-domains were structured. To demonstrate the involvement of disorder in E3 function, we applied normal modes and molecular dynamics analyses to show how a disordered and highly flexible linker in human CBL (an E3 that acts as a regulator of several tyrosine kinase-mediated signalling pathways) facilitates long-range conformational changes bringing substrate and E2-binding domains towards each other and thus assisting in ubiquitin transfer. E3s with multiple interaction partners (as evidenced by data in STRING) also possess elevated levels of disorder (hubs, 22.90% vs. non-hubs, 18.36%). Furthermore, a search in PDB uncovered 21 distinct human E3 interactions, in 7 of which the disordered region of E3s undergoes induced folding (or mutual induced folding) in the presence of the partner. In conclusion, our data highlights the primary role of structural disorder in the functions of E3 ligases that manifests itself in the substrate/adaptor binding functions as well as the mechanism of ubiquitin transfer by long-range conformational transitions. © 2013 Bhowmick et al

Exploring and challenging the network of angiogenesis

Angiogenesis is one of the hallmarks of cancer and, as such, one of the alternative general targets for anticancer therapy. Since angiogenesis is a complex process involving a high number of interconnected components, a network approach would be a convenient systemic way to analyse responses to directed drug attacks. Herein we show that, although the angiogenic network is easily broken by short combinations of directed attacks, it still remains essentially functional by keeping the global patterns and local efficiency essentially unaltered after these attacks. This is a clear sign of its high robustness and resilience and stresses the need of directed, combined attacks for an effective blockade of the process. The results of this theoretical study could be relevant for the design of new antiangiogenic therapies and the selection of their targets

Functional diversity of mesograzers in an eelgrass-epiphyte system

Historically, small invertebrate grazers in marine plant communities have been considered to be a relatively homogeneous group in their impact on ecosystem processes. However, recent studies propose that species composition is an important agent in determining grazer effects. We used four mesocosm experiments to test the biomass-specific and density-dependent effects of common mesograzers in temperate regions (Littorina littorea, Rissoa membranacea, Idotea baltica and Gammarus oceanicus) on epiphyte and eelgrass biomass and productivity. Mesograzer species identity strongly influenced epiphyte accumulation and eelgrass growth, where Rissoa was the most efficient mesograzer (per biomass) and Gammarus had the weakest impact. Density-dependent effects varied considerably among species. Both gastropod species reduced epiphyte accumulation in direct proportion to their density, and Littorina had the strongest negative effect on epiphyte biomass. The impact of Idotea seemed to level off to a threshold value and Gammarus had no density-dependent effect on epiphyte accumulation at all. Rissoa and Idotea increased eelgrass productivity in accordance with their effect on epiphyte accumulation, whereas Littorina showed a less positive effect than could be expected by its strong impact on epiphyte biomass. Gammarus had no significant impact on eelgrass growth. Our results show that the different functional traits of superficially similar mesograzers can have important consequences for ecosystem processes in macrophyte systems

Self-reported health status of older adults in Malaysia and Singapore: evidence from the 2007 Global Ageing Survey

The aim of this study is to investigate the correlates of self-reported health (SRH) among older adults in Malaysia and Singapore. The study uses data collected in the Global Ageing Study (GLAS) 2007, one of the largest surveys of its kind, specially designed to investigate attitudes towards later life, ageing and retirement. Data were collected from 1002 and 1004 respondents from Malaysia and Singapore respectively. The study found that Singaporeans report a healthier life than Malaysians. The two countries have consistent results with regard to the influences of selected covariates on individual health. Poorer health is more prevalent among people with lower education, among those widowed, divorced or separated, and those working in blue-collar occupations. Although social support is found to be an important determinant of SRH, the effects are partially confounded with other covariates. These findings enhance our knowledge about the health status of older people, and in turn will be useful for governments to ensure effective policy making

Outcomes of resection for colorectal cancer hepatic metastases stratified by evolving eras of treatment

<p>Abstract</p> <p>Background and purpose</p> <p>The outcomes and management of colorectal cancer (CRC) hepatic metastasis have undergone many evolutionary changes. In this study, we aimed to analyze the outcomes of patients with CRC hepatic metastasis in terms of the era of treatment.</p> <p>Methods</p> <p>We conducted a retrospective review of 279 patients who underwent liver resection (LR) for CRC hepatic metastases. The prognoses of patients treated pre-2003 (era 1) and post-2003 (era 2) were examined.</p> <p>Results</p> <p>Of the patients included in the study, 210 (75.3%) had CRC recurrence after LR. There was a significant difference in the ratio of CRC recurrence between the 2 eras (82.0% in era 1 <it>vs</it>. 69.5% in era 2; <it>p </it>= 0.008). Analysis of recurrence-free and overall survival rates also showed that the patient outcome was significantly better in the post-2003 era than in the pre-2003 era. Further analysis showed that a significantly higher percentage of patients in era 2 had received modern chemotherapeutic regimens including irinotecan and oxaliplatin, while patients in era 1 were mainly administered fluorouracil and leucovorin for adjuvant chemotherapy. Among patients with CRC recurrence, a significant ratio of those in era 2 underwent surgical resection for recurrent lesions, and these patients had a better survival curve than did patients without resection (34.1% <it>vs</it>. 2.2% for 5-year survival; <it>p </it>< 0.0001).</p> <p>Conclusion</p> <p>The incidence of CRC recurrence after LR for hepatic metastasis remains very high. However, the management and outcomes of patients with CRC hepatic metastasis have greatly improved with time, suggesting that the current use of aggressive multimodality treatments including surgical resection combined with modern chemotherapeutic regimens effectively prolongs the life expectancy of these patients.</p