809 research outputs found
Collaborative Computation in Self-Organizing Particle Systems
Many forms of programmable matter have been proposed for various tasks. We
use an abstract model of self-organizing particle systems for programmable
matter which could be used for a variety of applications, including smart paint
and coating materials for engineering or programmable cells for medical uses.
Previous research using this model has focused on shape formation and other
spatial configuration problems (e.g., coating and compression). In this work we
study foundational computational tasks that exceed the capabilities of the
individual constant size memory of a particle, such as implementing a counter
and matrix-vector multiplication. These tasks represent new ways to use these
self-organizing systems, which, in conjunction with previous shape and
configuration work, make the systems useful for a wider variety of tasks. They
can also leverage the distributed and dynamic nature of the self-organizing
system to be more efficient and adaptable than on traditional linear computing
hardware. Finally, we demonstrate applications of similar types of computations
with self-organizing systems to image processing, with implementations of image
color transformation and edge detection algorithms
Genotypic variation in phosphorus efficiency between wheat cultivars grown under greenhouse and field conditions
Phosphorus (P) efficiency (relative growth), which is described as the ratio of shoot dry matter or grain yield at deficient P supply to that obtained under adequate P supply, was compared in 25 winter wheat cultivars grown under greenhouse and field conditions with low and adequate P levels in a P-deficient calcareous soil. Adequate P supply resulted in significant increases in shoot dry weight and grain yield under both experimental conditions. In the greenhouse experiment, the increases in shoot dry weight under adequate P supply (80 mg kg(-1)) were from 0% (cv: C-1252) to 34% (cv: Dagdas). Under field conditions, the cultivars showed much greater variation in their response to adequate P supply (60 kg ha(-1)): the increases in shoot dry weight and grain yield with adequate P supply were between -2% (cv: Sivas-111/33) and 25% (cv: Kirac-66) for shoot dry matter production at the heading stage and between 0% (cv: Kirkpinar-79) and 76% (cv: Kate A-1) for grain yield at maturity. Almost all cultivars behaved totally different in their response to P deficiency under greenhouse and field conditions. Phosphorus efficiency ratios (relative growth) under greenhouse conditions did not correlate with the P efficiency ratios under field conditions. In general, durum wheat cultivars were found to be more P efficient compared with bread wheat cultivars. The results of this study indicated that there is wide variation in tolerance to P deficiency among wheat cultivars that can be exploited in breeding new wheat cultivars for high P deficiency tolerance. The results also demonstrated that P efficiency was expressed differently among the wheat cultivars when grown under greenhouse and field conditions and, therefore, special attention should be paid to growth conditions in screening wheat for P efficiency
Spatial and temporal genetic heterogeneity of epidermal growth factor receptor gene status in a patient with non-small cell lung cancer: a case report
<p>Abstract</p> <p>Introduction</p> <p>To date, an epidermal growth factor receptor-activating mutation is recognized as a genetic hallmark that predicts a good response to treatment with epidermal growth factor receptor tyrosine kinase inhibitor. However, there has been less long-term observation of the mutational status within the same patient. To the best of our knowledge, this is the first case report which illustrates the instability of the genetic status of pulmonary adenocarcinoma cells.</p> <p>Case presentation</p> <p>A 64-year-old Japanese woman with advanced lung adenocarcinoma had been undergoing various anticancer treatments, including epidermal growth factor receptor tyrosine kinase inhibitor, for seven years. She had been receiving locoregional treatment in addition to systemic treatment. She maintained a good performance status until seven years after the initial diagnosis, although she had local and distant recurrences. We analyzed the genetic status of the epidermal growth factor receptor gene in a series of specimens obtained from various tumor-containing lesions throughout the therapeutic period. The results of the genetic analyses clearly showed that the spatial and temporal genetic heterogeneity of the epidermal growth factor receptor gene status originated from an identical tumor ancestor.</p> <p>Conclusions</p> <p>An alternative paradigm to determine a therapeutic strategy for a patient with lung cancer should be considered given the genetic heterogeneity and instability of tumor cells.</p
Edible crabs βGo Westβ: migrations and incubation cycle of Cancer pagurus revealed by electronic tags
Crustaceans are key components of marine ecosystems which, like other exploited marine taxa, show seasonable patterns of distribution and activity, with consequences for their availability to capture by targeted fisheries. Despite concerns over the sustainability of crab fisheries worldwide, difficulties in observing crabsβ behaviour over their annual cycles, and the timings and durations of reproduction, remain poorly understood. From the release of 128 mature female edible crabs tagged with electronic data storage tags (DSTs), we demonstrate predominantly westward migration in the English Channel. Eastern Channel crabs migrated further than western Channel crabs, while crabs released outside the Channel showed little or no migration. Individual migrations were punctuated by a 7-month hiatus, when crabs remained stationary, coincident with the main period of crab spawning and egg incubation. Incubation commenced earlier in the west, from late October onwards, and brooding locations, determined using tidal geolocation, occurred throughout the species range. With an overall return rate of 34%, our results demonstrate that previous reluctance to tag crabs with relatively high-cost DSTs for fear of loss following moulting is unfounded, and that DSTs can generate precise information with regards life-history metrics that would be unachievable using other conventional means
Rethinking Design : A Dialogue on Anti-Racism and Art Activism from a Decolonial Perspective
This chapter focuses on feminist anti-racist activism from a decolonial perspective in the field of cultural production. The authors analyze racialized and racist representations in Finland, and propose interventions from a decolonial perspective. We propose a number of strategies in the field of representation to create non-stereotypical and demeaning racist images, in order to challenge and transform racialized representational practices. We analyze our experience of Finland through concepts such as the white savior complex, white fragility and racial illiteracy to grasp the specificity of the ways through which racism is given meaning and acted upon.Peer reviewe
Extensive Copy-Number Variation of Young Genes across Stickleback Populations
MM received funding from the Max Planck innovation funds for this project. PGDF was supported by a Marie Curie European Reintegration Grant (proposal nr 270891). CE was supported by German Science Foundation grants (DFG, EI 841/4-1 and EI 841/6-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Molecular Analysis of Precursor Lesions in Familial Pancreatic Cancer
PMCID: PMC3553106This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
An examination of the Apo-1/Fas promoter Mva I polymorphism in Japanese patients with multiple sclerosis
BACKGROUND: The Apo-1/Fas (CD95) molecule is an apoptosis-signaling cell surface receptor belonging to the tumor necrosis factor (TNF) receptor family. Both Fas and Fas ligand (FasL) are expressed in activated mature T cells, and prolonged cell activation induces susceptibility to Fas-mediated apoptosis. The Apo-1/Fas gene is located in a chromosomal region that shows linkage in multiple sclerosis (MS) genome screens, and studies indicate that there is aberrant expression of the Apo-1/Fas molecule in MS. METHODS: Mva I polymorphism on the Apo-1/Fas promoter gene was detected by PCR-RFLP from the DNA of 114 Japanese patients with conventional MS and 121 healthy controls. We investigated the association of the Mva I polymorphism in Japanese MS patients using a case-control association study design. RESULTS: We found no evidence that the polymorphism contributes to susceptibility to MS. Furthermore, there was no association between Apo-1/Fas gene polymorphisms and clinical course (relapsing-remitting course or secondary-progressive course). No significant association was observed between Apo-1/Fas gene polymorphisms and the age at disease onset. CONCLUSIONS: Overall, our findings suggest that Apo-1/Fas promoter gene polymorphisms are not conclusively related to susceptibility to MS or the clinical characteristics of Japanese patients with MS
Fluorescence-based high-throughput functional profiling of ligand-gated ion channels at the level of single cells
Ion channels are involved in many physiological processes and are attractive targets for therapeutic intervention. Their functional properties vary according to their subunit composition, which in turn varies in a developmental and tissue-specific manner and as a consequence of pathophysiological events. Understanding this diversity requires functional analysis of ion channel properties in large numbers of individual cells. Functional characterisation of ligand-gated channels involves quantitating agonist and drug dose-response relationships using electrophysiological or fluorescence-based techniques. Electrophysiology is limited by low throughput and high-throughput fluorescence-based functional evaluation generally does not enable the characterization of the functional properties of each individual cell. Here we describe a fluorescence-based assay that characterizes functional channel properties at single cell resolution in high throughput mode. It is based on progressive receptor activation and iterative fluorescence imaging and delivers >100 dose-responses in a single well of a 384-well plate, using Ξ±1-3 homomeric and Ξ±Ξ² heteromeric glycine receptor (GlyR) chloride channels as a model system. We applied this assay with transiently transfected HEK293 cells co-expressing halide-sensitive yellow fluorescent protein and different GlyR subunit combinations. Glycine EC values of different GlyR isoforms were highly correlated with published electrophysiological data and confirm previously reported pharmacological profiles for the GlyR inhibitors, picrotoxin, strychnine and lindane. We show that inter and intra well variability is low and that clustering of functional phenotypes permits identification of drugs with subunit-specific pharmacological profiles. As this method dramatically improves the efficiency with which ion channel populations can be characterized in the context of cellular heterogeneity, it should facilitate systems-level analysis of ion channel properties in health and disease and the discovery of therapeutics to reverse pathological alterations
Elusive Origins of the Extra Genes in Aspergillus oryzae
The genome sequence of Aspergillus oryzae revealed unexpectedly that this species has approximately 20% more genes than its congeneric species A. nidulans and A. fumigatus. Where did these extra genes come from? Here, we evaluate several possible causes of the elevated gene number. Many gene families are expanded in A. oryzae relative to A. nidulans and A. fumigatus, but we find no evidence of ancient whole-genome duplication or other segmental duplications, either in A. oryzae or in the common ancestor of the genus Aspergillus. We show that the presence of divergent pairs of paralogs is a feature peculiar to A. oryzae and is not shared with A. nidulans or A. fumigatus. In phylogenetic trees that include paralog pairs from A. oryzae, we frequently find that one of the genes in a pair from A. oryzae has the expected orthologous relationship with A. nidulans, A. fumigatus and other species in the subphylum Eurotiomycetes, whereas the other A. oryzae gene falls outside this clade but still within the Ascomycota. We identified 456 such gene pairs in A. oryzae. Further phylogenetic analysis did not however indicate a single consistent evolutionary origin for the divergent members of these pairs. Approximately one-third of them showed phylogenies that are suggestive of horizontal gene transfer (HGT) from Sordariomycete species, and these genes are closer together in the A. oryzae genome than expected by chance, but no unique Sordariomycete donor species was identifiable. The postulated HGTs from Sordariomycetes still leave the majority of extra A. oryzae genes unaccounted for. One possible explanation for our observations is that A. oryzae might have been the recipient of many separate HGT events from diverse donors
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