1,774 research outputs found
The role of initial geometry in experimental models of wound closing
Wound healing assays are commonly used to study how populations of cells,
initialised on a two-dimensional surface, act to close an artificial wound
space. While real wounds have different shapes, standard wound healing assays
often deal with just one simple wound shape, and it is unclear whether varying
the wound shape might impact how we interpret results from these experiments.
In this work, we describe a new kind of wound healing assay, called a sticker
assay, that allows us to examine the role of wound shape in a series of wound
healing assays performed with fibroblast cells. In particular, we show how to
use the sticker assay to examine wound healing with square, circular and
triangular shaped wounds. We take a standard approach and report measurements
of the size of the wound as a function of time. This shows that the rate of
wound closure depends on the initial wound shape. This result is interesting
because the only aspect of the assay that we change is the initial wound shape,
and the reason for the different rate of wound closure is unclear. To provide
more insight into the experimental observations we describe our results
quantitatively by calibrating a mathematical model, describing the relevant
transport phenomena, to match our experimental data. Overall, our results
suggest that the rates of cell motility and cell proliferation from different
initial wound shapes are approximately the same, implying that the differences
we observe in the wound closure rate are consistent with a fairly typical
mathematical model of wound healing. Our results imply that parameter estimates
obtained from an experiment performed with one particular wound shape could be
used to describe an experiment performed with a different shape. This
fundamental result is important because this assumption is often invoked, but
never tested
A Learning Game For Youth Financial Literacy Education In The Teen Grid Of Second Life Three-Dimensional Virtual Environment
Game-like three-dimensional (3D) virtual worlds have become popular venues for youth to explore and interact with friends. To bring vital financial literacy education to them in places they frequent, a multi-disciplinary team of computer scientists, educators, and financial experts developed a youth-oriented financial literacy education game in the Teen Grid of Second Life 3D online virtual world. This paper presents the design and development process of this financial literacy education game, its learning effectiveness in classrooms, and lessons learned from the process
Innovative concrete sensing technologies for nuclear power plants
Postupak nerazornog ispitivanja primjenjuje se za istraĆŸivanja tijekom izvoÄenja i uporabe betonskih konstrukcija koje se koriste za potrebe nuklearne industrije. Beton u nuklearnim elektranama Äesto se odlikuje posebnim svojstvima koja ga Äine osjetljivim na propadanje te koja onemoguÄuju analizu i kontrolu pomoÄu tradicionalnih nerazornih postupaka. Moderne tehnologije analize unutar betona omoguÄuju dubinsko istraĆŸivanje nuklearnih armiranobetonskih konstrukcija. U radu se analiziraju perspektivne dubinske i povrĆĄinske analitiÄke metode te se kritiÄki ocjenjuje primjena senzora u analizi betonskih konstrukcija koje se koriste u nuklearnoj industriji.Nondestructive evaluation has been used to investigate construction and use of concrete structures for the nuclear power industry. Nuclear concrete often has unique structural characteristics which increase proclivity towards degradation and inhibit analysis and inspection using traditional nondestructive techniques. Modern embedded sensing technologies can provide opportunities for the in-depth evaluation of nuclear reinforced-concrete structures. This paper offers an assessment of emerging embedded and surficial sensor techniques, and critically evaluates sensor applicability in the analysis of concrete structures used in the nuclear power industry
Rising to Ostromâs challenge:An invitation to walk on the bright side of public governance and public service
In this programmatic essay, we argue that public governance scholarship would benefit from developing a self-conscious and cohesive strand of "positive" scholarship, akin to social science subfields like positive psychology, positive organizational studies, and positive evaluation. We call for a program of research devoted to uncovering the factors and mechanisms that enable high performing public policies and public service delivery mechanisms; procedurally and distributively fair processes of tackling societal conflicts; and robust and resilient ways of coping with threats and risks. The core question driving positive public administration scholarship should be: Why is it that particular public policies, programs, organizations, networks, or partnerships manage do much better than others to produce widely valued societal outcomes, and how might knowledge of this be used to advance institutional learning from positives
Gender, migration and the ambiguous enterprise of professionalizing domestic service: the case of vocational training for the unemployed in France
Drawing on ethnographic data concerning migrant male domestic workers, this article examines the gendered dimensions of the process of racialization in Italy and France. First, it shows that specific racialized constructions of masculinity are mobilized by the employers as well as by training and recruitment agencies. These constructions of masculinity are related to different forms of organization of the sector in each country and to different ideologies about the integration of migrants. Second, the data presented reveal the strategies used by migrant male domestic workers to reaffirm their masculinity in a traditionally feminized sector. In doing so, this article intends to explore the connections between international migration and the gendering of occupations, with regard to the construction and management of masculinities in domestic service. Finally, by examining menâs experiences, this article aims to contribute to a more complex definition of the international division of care work
Evidence for the role of EPHX2 gene variants in anorexia nervosa.
Anorexia nervosa (AN) and related eating disorders are complex, multifactorial neuropsychiatric conditions with likely rare and common genetic and environmental determinants. To identify genetic variants associated with AN, we pursued a series of sequencing and genotyping studies focusing on the coding regions and upstream sequence of 152 candidate genes in a total of 1205 AN cases and 1948 controls. We identified individual variant associations in the Estrogen Receptor-Ă (ESR2) gene, as well as a set of rare and common variants in the Epoxide Hydrolase 2 (EPHX2) gene, in an initial sequencing study of 261 early-onset severe AN cases and 73 controls (P=0.0004). The association of EPHX2 variants was further delineated in: (1) a pooling-based replication study involving an additional 500 AN patients and 500 controls (replication set P=0.00000016); (2) single-locus studies in a cohort of 386 previously genotyped broadly defined AN cases and 295 female population controls from the Bogalusa Heart Study (BHS) and a cohort of 58 individuals with self-reported eating disturbances and 851 controls (combined smallest single locus P<0.01). As EPHX2 is known to influence cholesterol metabolism, and AN is often associated with elevated cholesterol levels, we also investigated the association of EPHX2 variants and longitudinal body mass index (BMI) and cholesterol in BHS female and male subjects (N=229) and found evidence for a modifying effect of a subset of variants on the relationship between cholesterol and BMI (P<0.01). These findings suggest a novel association of gene variants within EPHX2 to susceptibility to AN and provide a foundation for future study of this important yet poorly understood condition
(13) C magnetic resonance spectroscopy measurements with hyperpolarized [1-(13) C] pyruvate can be used to detect the expression of transgenic pyruvate decarboxylase activity in vivo.
PURPOSE: Dissolution dynamic nuclear polarization can increase the sensitivity of the (13) C magnetic resonance spectroscopy experiment by at least four orders of magnitude and offers a novel approach to the development of MRI gene reporters based on enzymes that metabolize (13) C-labeled tracers. We describe here a gene reporter based on the enzyme pyruvate decarboxylase (EC 4.1.1.1), which catalyzes the decarboxylation of pyruvate to produce acetaldehyde and carbon dioxide. METHODS: Pyruvate decarboxylase from Zymomonas mobilis (zmPDC) and a mutant that lacked enzyme activity were expressed using an inducible promoter in human embryonic kidney (HEK293T) cells. Enzyme activity was measured in the cells and in xenografts derived from the cells using (13) C MRS measurements of the conversion of hyperpolarized [1-(13) C] pyruvate to H(13) CO3-. RESULTS: Induction of zmPDC expression in the cells and in the xenografts derived from them resulted in an approximately two-fold increase in the H(13) CO3-/[1-(13) C] pyruvate signal ratio following intravenous injection of hyperpolarized [1-(13) C] pyruvate. CONCLUSION: We have demonstrated the feasibility of using zmPDC as an in vivo reporter gene for use with hyperpolarized (13) C MRS. Magn Reson Med 76:391-401, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.PD was in receipt of a studentship funded by CRUK and S.-S.T. a Yousef Jameel studentship. TBR was in receipt of an Intra-European Marie Curie (FP7-PEOPLE- 2009-IEF, Imaging Lymphoma) and Long-term EMBO (EMBO-ALT-1145-2009) fellowships and E.M.S. and I.M.R were recipients of fellowships from the European Union Seventh Framework Programme (FP7/2007-2013) under the Marie Curie Initial Training Network METAFLUX (project number 264780). E.M.S. also acknowledges the educational support of Programme for Advanced Medical Education from Calouste Gulbenkian Foundation, Champalimaud Foundation, Ministerio de Saude and Fundacao para a Ciencia e Tecnologia, Portugal. The work was supported by a CRUK Programme Grant (17242) to KMB. The polarizer and related materials were provided by GE-Healthcare.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/mrm.2587
A realtime observatory for laboratory simulation of planetary flows
Motivated by the large-scale circulation of the atmosphere and ocean, we develop a system that uses
observations from a laboratory analog to constrain, in real time, a numerical simulation of the laboratory
flow. This system provides a tool to rapidly prototype new methods for state and parameter
estimation, and facilitates the study of prediction, predictability, and transport of geophysical fluids
where observations or numerical simulations would not independently suffice.
A computer vision system is used to extract measurements of the physical simulation. Observations
are used to constrain the model-state of the MIT General Circulation Model in a probabilistic, ensemble based assimilation approach. Using a combination of parallelism, domain decomposition and an efficient
scheme to select ensembles of model-states, we show that estimates that effectively track the fluid state
can be produced. To the best of our knowledge this is the first such observatory for laboratory
analogs of planetary circulation that functions in real time.National Science Foundation (U.S.) (CNS-0540259)National Science Foundation (U.S.) (grant CNS-0540248
Genome-wide linkage analysis of 972 bipolar pedigrees using single-nucleotide polymorphisms.
Because of the high costs associated with ascertainment of families, most linkage studies of Bipolar I disorder (BPI) have used relatively small samples. Moreover, the genetic information content reported in most studies has been less than 0.6. Although microsatellite markers spaced every 10âcM typically extract most of the genetic information content for larger multiplex families, they can be less informative for smaller pedigrees especially for affected sib pair kindreds. For these reasons we collaborated to pool family resources and carried out higher density genotyping. Approximately 1100 pedigrees of European ancestry were initially selected for study and were genotyped by the Center for Inherited Disease Research using the Illumina Linkage Panel 12 set of 6090 single-nucleotide polymorphisms. Of the ~1100 families, 972 were informative for further analyses, and mean information content was 0.86 after pruning for linkage disequilibrium. The 972 kindreds include 2284 cases of BPI disorder, 498 individuals with bipolar II disorder (BPII) and 702 subjects with recurrent major depression. Three affection status models (ASMs) were considered: ASM1 (BPI and schizoaffective disorder, BP cases (SABP) only), ASM2 (ASM1 cases plus BPII) and ASM3 (ASM2 cases plus recurrent major depression). Both parametric and non-parametric linkage methods were carried out. The strongest findings occurred at 6q21 (non-parametric pairs LOD 3.4 for rs1046943 at 119âcM) and 9q21 (non-parametric pairs logarithm of odds (LOD) 3.4 for rs722642 at 78âcM) using only BPI and schizoaffective (SA), BP cases. Both results met genome-wide significant criteria, although neither was significant after correction for multiple analyses. We also inspected parametric scores for the larger multiplex families to identify possible rare susceptibility loci. In this analysis, we observed 59 parametric LODs of 2 or greater, many of which are likely to be close to maximum possible scores. Although some linkage findings may be false positives, the results could help prioritize the search for rare variants using whole exome or genome sequencing
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