Organization of the Smallest Eukaryotic Spindle

In metazoans, plants, and fungi, the spindle checkpoint delays mitosis until each chromosome is attached to one or more of its own kinetochore microtubules (kMTs). Some unicellular eukaryotes, however, have been reported to have fewer kMTs than chromosomes. If this is the case, it is unclear how the spindle checkpoint could be satisfied. In the vast majority of the previous studies, mitotic cells were chemically fixed at room temperature, but this does not always preserve dynamic and/or small structures like spindle MTs and kinetochores. Indeed, later higher-resolution studies have reversed some earlier claims. Here we show that in Ostreococcus tauri (the smallest eukaryote known), mitosis does involve fewer spindle microtubules than chromosomes. O. tauri cultures were enriched for mitotic cells, high-pressure frozen, and then imaged in 3D both in plastic and in a near-native ("frozen-hydrated") state through electron tomography. Mitotic cells have a distinctive intranuclear heterochromatin-free "spindle tunnel" with approximately four short and occasionally one long, incomplete (unclosed) microtubule at each end of the spindle tunnel. Because other aspects of O. tauri’s spindle checkpoint seem typical, these data suggest that O. tauri’s 20 chromosomes are physically linked and segregated as just one or a small number of groups

Optimal aeroassisted intercept trajectories at hyperbolic speeds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76250/1/AIAA-1989-3444-892.pd

Optimal aeroassisted intercept trajectories at hyperbolic speeds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76040/1/AIAA-20613-974.pd

High Quality Audio Coding with MDCTNet

We propose a neural audio generative model, MDCTNet, operating in the perceptually weighted domain of an adaptive modified discrete cosine transform (MDCT). The architecture of the model captures correlations in both time and frequency directions with recurrent layers (RNNs). An audio coding system is obtained by training MDCTNet on a diverse set of fullband monophonic audio signals at 48 kHz sampling, conditioned by a perceptual audio encoder. In a subjective listening test with ten excerpts chosen to be balanced across content types, yet stressful for both codecs, the mean performance of the proposed system for 24 kb/s variable bitrate (VBR) is similar to that of Opus at twice the bitrate.Comment: Five pages, five figure

Submm/mm Galaxy Counterpart Identification Using a Characteristic Density Distribution

We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer IRAC colors as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and SMA-confirmed counterparts to AzTEC sources across three fields (GOODS-N, GOODS-S, and COSMOS), we develop a non-parametric IRAC color-color characteristic density distribution (CDD), which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around SMGs and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beamsize (~18"), this technique identifies ~85 per cent of SMG counterparts. For much larger beamsizes (>30"), we report identification rates of 33-49 per cent. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the LMT and SCUBA-2 on JCMT.Comment: 30 pages, 9 figures, 5 tables. Accepted for publication in MNRA

Electron tomography of cells

The electron microscope has contributed deep insights into biological structure since its invention nearly 80 years ago. Advances in instrumentation and methodology in recent decades have now enabled electron tomography to become the highest resolution three-dimensional (3D) imaging technique available for unique objects such as cells. Cells can be imaged either plastic-embedded or frozen-hydrated. Then the series of projection images are aligned and back-projected to generate a 3D reconstruction or ‘tomogram’. Here, we review how electron tomography has begun to reveal the molecular organization of cells and how the existing and upcoming technologies promise even greater insights into structural cell biology

In vivo clonal expansion and phenotypes of hypocretin-specific CD4(+) T cells in narcolepsy patients and controls

Individuals with narcolepsy suffer from abnormal sleep patterns due to loss of neurons that uniquely supply hypocretin (HCRT). Previous studies found associations of narcolepsy with the human leukocyte antigen (HLA)-DQ6 allele and T-cell receptor alpha (TRA) J24 gene segment and also suggested that in vitro-stimulated T cells can target HCRT. Here, we present evidence of in vivo expansion of DQ6-HCRT tetramer(+)/TRAJ24(+)/CD4(+) T cells in DQ6(+) individuals with and without narcolepsy. We identify related TRAJ24(+) TCRalphabeta clonotypes encoded by identical alpha/beta gene regions from two patients and two controls. TRAJ24-G allele(+) clonotypes only expand in the two patients, whereas a TRAJ24-C allele(+) clonotype expands in a control. A representative tetramer(+)/G-allele(+) TCR shows signaling reactivity to the epitope HCRT87-97. Clonally expanded G-allele(+) T cells exhibit an unconventional effector phenotype. Our analysis of in vivo expansion of HCRT-reactive TRAJ24(+) cells opens an avenue for further investigation of the autoimmune contribution to narcolepsy development

Open building for a kaleidoscope of care: a new conceptual approach to open scenario planning

Open scenario planning, in a market such as healthcare infrastructure where change at every scale is inevitable, provides a significant opportunity. Healthcare, which comprises a complex mix of people, technology, buildings and other forms of infrastructure, is facing huge pressures. As such healthcare trusts are looking to make better use of resources; decrease carbon emissions; and re-think how they can act in a more sustainable and integrated way. Within the UK National Health Service, “taking care closer to home” and “saving carbon, improving health” are two of a number of Department of Health (DH) initiatives to improve healthcare and respond to the need for sustainable, accessible, efficient and effective services. Furthermore these are also the drivers for integration between health, social care, local authority, independent and third sector providers which is creating blurring between spatial scales and roles. Against this backdrop it is not surprising that the effective life span of buildings is continuing to shorten, which is significant in a sector that has infrastructure that is one of the most expensive to operate, maintain and replace. As such the notion of “change ready” is key. This paper through a state-of-the-art literature review introduces and explores the potential and conceptual linkage between infrastructure, capacity and scalability within open building and planning extending (Astley, 2009; Kendall, 2009). The authors’ collaborative and action research has contributed to the development of a new approach and this research has identified the need for a flexible, dynamic and scenario based approach to planning that goes beyond estates strategy and beyond master planning and which precedes open building. The diversity of care pathways across a changing healthcare planning environments is demonstrated using a case study review, which raises the importance of a hierarchy of decision making, principles and process within an open planning approach. This paper further provides a review of existing business case development processes and capacity planning tools that are prevalent in healthcare strategic planning and operations management, but not so in adaptability research. Scalability as a concept that can bridge the healthcare and estates infrastructure domains is also introduced

MicroRNA-143 activation regulates smooth muscle and endothelial cell crosstalk in pulmonary arterial hypertension

Rationale: The pathogenesis of PAH remains unclear. The four microRNAs representing the miR-143 and miR-145 stem loops are genomically clustered. Objective: To elucidate the transcriptional regulation of the miR-143/145 cluster, and the role of miR-143 in PAH. Methods and Results: We identified the promoter region that regulates miR-143/145 miRNA expression in pulmonary artery smooth muscle cells (PASMCs). We mapped PAH-related signalling pathways, including estrogens receptor (ER), liver X factor/retinoic X receptor (LXR/RXR), TGF-β (Smads), and hypoxia (HRE) that regulated levels of all pri-miR stem loop transcription and resulting miRNA expression. We observed that miR-143-3p is selectively upregulated compared to miR-143-5p during PASMC migration. Modulation of miR-143 in PASMCs significantly altered cell migration and apoptosis. In addition, we found high abundance of miR-143-3p in PASMCs-derived exosomes. Using assays with pulmonary arterial endothelial cells (PAECs) we demonstrated a paracrine pro-migratory and pro-angiogenic effect of miR-143-3p enriched exosomes from PASMC. Quantitative PCR and in situ hybridisation showed elevated expression of miR-143 in calf models of PAH as well as in samples from PAH patients. Moreover, in contrast to our previous findings that had not supported a therapeutic role in vivo, we now demonstrate a protective role for miR-143 in experimental PH in vivo in miR-143-/- and antimiR143-3p-treated mice exposed to chronic hypoxia in both preventative and reversal settings. Conclusions: MiR-143-3p modulated both cellular and exosome-mediated responses in pulmonary vascular cells, while inhibition of miR-143-3p blocked experimental PH. Taken together these findings confirm an important role for the miR-143/145 cluster in PAH pathobiology