The advent of genome editing techniques based on the clustered regularly interspersed short palindromic repeats (CRISPR)-Cas9 system has revolutionized research in the biological sciences. CRISPR is ...quickly becoming an indispensible experimental tool for researchers using genetic model organisms, including the nematode Caenorhabditis elegans. Here, we provide an overview of CRISPR-based strategies for genome editing in C. elegans. We focus on practical considerations for successful genome editing, including a discussion of which strategies are best suited to producing different kinds of targeted genome modifications.
Measuring consumer-based brand authenticity Napoli, Julie; Dickinson, Sonia J.; Beverland, Michael B. ...
Journal of business research,
06/2014, Letnik:
67, Številka:
6
Journal Article
Recenzirano
Postmodern consumers use brands to create an authentic self and to reconnect to place, time, culture and others. Although previous research has identified that consumers draw on a range of cues in ...order to attribute authenticity to branded objects, no scales exist to measure the construct of brand authenticity. Building on the existing literature, this paper uses quantitative methods to develop a psychometrically robust measure of brand authenticity from a consumer's perspective. Findings demonstrate convergent, discriminant and predictive validity, whereby 14 items represent three interrelated first order factors labeled quality commitment, sincerity and heritage that correspond with a higher order brand authenticity construct. This study extends our understanding of the consumption of authenticity. Moreover, it provides a tool by which firms can evaluate the effectiveness of strategic decisions designed to deliver an authentic brand offering to consumers. Limitations and directions for future research are discussed.
The authors provide a metrology-led perspective on best practice for the electrochemical characterisation of materials for electrochemical energy technologies. Such electrochemical experiments are ...highly sensitive, and their results are, in practice, often of uncertain quality and challenging to reproduce quantitatively.
Regulated protein-protein interactions are critical for cell signaling, differentiation, and development. For the study of dynamic regulation of protein interactions in vivo, there is a need for ...techniques that can yield time-resolved information and probe multiple protein binding partners simultaneously, using small amounts of starting material. Here we describe a single-cell protein interaction assay. Single-cell lysates are generated at defined time points and analyzed using single-molecule pull-down, yielding information about dynamic protein complex regulation in vivo. We established the utility of this approach by studying PAR polarity proteins, which mediate polarization of many animal cell types. We uncovered striking regulation of PAR complex composition and stoichiometry during Caenorhabditis elegans zygote polarization, which takes place in less than 20 min. PAR complex dynamics are linked to the cell cycle by Polo-like kinase 1 and govern the movement of PAR proteins to establish polarity. Our results demonstrate an approach to study dynamic biochemical events in vivo.
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•Protein interactions are assayed in single-cell lysates via single-molecule pull-down•This approach provides time-resolved information about protein complex regulation•PAR complex oligomerization occurs during cell polarity establishment in C. elegans•Oligomerization is linked to the cell cycle and controls PAR complex segregation
Single-cell analysis is becoming increasingly important for cell biology. Dickinson et al. describe a single-cell assay for protein interactions, using microfluidic lysis and single-molecule pull-down. They apply this approach to show that PAR complex assembly is dynamic and is linked to the cell cycle during cell polarization in C. elegans.
TurboPixels: Fast Superpixels Using Geometric Flows Levinshtein, A.; Stere, A.; Kutulakos, K.N. ...
IEEE transactions on pattern analysis and machine intelligence,
12/2009, Letnik:
31, Številka:
12
Journal Article
Recenzirano
Odprti dostop
We describe a geometric-flow-based algorithm for computing a dense oversegmentation of an image, often referred to as superpixels. It produces segments that, on one hand, respect local image ...boundaries, while, on the other hand, limiting undersegmentation through a compactness constraint. It is very fast, with complexity that is approximately linear in image size, and can be applied to megapixel sized images with high superpixel densities in a matter of minutes. We show qualitative demonstrations of high-quality results on several complex images. The Berkeley database is used to quantitatively compare its performance to a number of oversegmentation algorithms, showing that it yields less undersegmentation than algorithms that lack a compactness constraint while offering a significant speedup over N-cuts, which does enforce compactness.
Copositive programming has become a useful tool in dealing with all sorts of optimisation problems. It has however been shown by Murty and Kabadi (Math. Program. 39(2):117–129,
1987
) that the strong ...membership problem for the copositive cone, that is deciding whether or not a given matrix is in the copositive cone, is a co-NP-complete problem. From this it has long been assumed that this implies that the question of whether or not the strong membership problem for the dual of the copositive cone, the completely positive cone, is also an NP-hard problem. However, the technical details for this have not previously been looked at to confirm that this is true. In this paper it is proven that the strong membership problem for the completely positive cone is indeed NP-hard. Furthermore, it is shown that even the weak membership problems for both of these cones are NP-hard. We also present an alternative proof of the NP-hardness of the strong membership problem for the copositive cone.
Summary Background In patients with suspected coronary heart disease, single-photon emission computed tomography (SPECT) is the most widely used test for the assessment of myocardial ischaemia, but ...its diagnostic accuracy is reported to be variable and it exposes patients to ionising radiation. The aim of this study was to establish the diagnostic accuracy of a multiparametric cardiovascular magnetic resonance (CMR) protocol with x-ray coronary angiography as the reference standard, and to compare CMR with SPECT, in patients with suspected coronary heart disease. Methods In this prospective trial patients with suspected angina pectoris and at least one cardiovascular risk factor were scheduled for CMR, SPECT, and invasive x-ray coronary angiography. CMR consisted of rest and adenosine stress perfusion, cine imaging, late gadolinium enhancement, and MR coronary angiography. Gated adenosine stress and rest SPECT used99m Tc tetrofosmin. The primary outcome was diagnostic accuracy of CMR. This trial is registered at controlled-trials.com , number ISRCTN77246133. Findings In the 752 recruited patients, 39% had significant CHD as identified by x-ray angiography. For multiparametric CMR the sensitivity was 86·5% (95% CI 81·8–90·1), specificity 83·4% (79·5–86·7), positive predictive value 77·2%, (72·1–81·6) and negative predictive value 90·5% (87·1–93·0). The sensitivity of SPECT was 66·5% (95% CI 60·4–72·1), specificity 82·6% (78·5–86·1), positive predictive value 71·4% (65·3–76·9), and negative predictive value 79·1% (74·8–82·8). The sensitivity and negative predictive value of CMR and SPECT differed significantly (p<0·0001 for both) but specificity and positive predictive value did not (p=0·916 and p=0·061, respectively). Interpretation CE-MARC is the largest, prospective, real world evaluation of CMR and has established CMR's high diagnostic accuracy in coronary heart disease and CMR's superiority over SPECT. It should be adopted more widely than at present for the investigation of coronary heart disease. Funding British Heart Foundation.
Light-activatable proteins allow precise spatial and temporal control of biological processes in living cells and animals. Several approaches have been developed for controlling protein localization ...with light, including the conditional inhibition of a nuclear localization signal (NLS) with the Light Oxygen Voltage (AsLOV2) domain of phototropin 1 from Avena sativa. In the dark, the switch adopts a closed conformation that sterically blocks the NLS motif. Upon activation with blue light the C-terminus of the protein unfolds, freeing the NLS to direct the protein to the nucleus. A previous study showed that this approach can be used to control the localization and activity of proteins in mammalian tissue culture cells. Here, we extend this result by characterizing the binding properties of a LOV/NLS switch and demonstrating that it can be used to control gene transcription in yeast. Additionally, we show that the switch, referred to as LANS (light-activated nuclear shuttle), functions in the C. elegans embryo and allows for control of nuclear localization in individual cells. By inserting LANS into the C. elegans lin-1 locus using Cas9-triggered homologous recombination, we demonstrated control of cell fate via light-dependent manipulation of a native transcription factor. We conclude that LANS can be a valuable experimental method for spatial and temporal control of nuclear localization in vivo.
Domestic gardens collectively cover substantial areas within cities and play an important role in supporting urban biodiversity and ecosystem functioning. The extent of their contribution to urban ...biodiversity is ultimately determined by the attitudes, motivations, and practices of their owners. We identified variables characterizing individual householders and their properties that explained variation in perennial plant and avian species richness and plant diversity among 55 gardens in New Zealand. The size of the vegetated area was most important in explaining bird and plant diversity, independent of property size. Also important and positively associated with plant richness were socio-economic status and ability to discriminate between native and exotic species. Median housing age and neighborhood green space were less important. Contrary to expectations, better educated householders who demonstrated pro-environmental orientation (NEP) did not necessarily have gardens with greater plant diversity, however, people with higher NEP scores tended to have gardens with more structurally complex vegetation. Similar variables were important in explaining native and exotic species richness, but higher exotic plant diversity was associated with older people with smaller properties of lower value. Avian species richness increased primarily with vegetated area, but also the areas of beds and hedges. We demonstrate that although householder knowledge is an important determinant of garden biodiversity, vegetated area is most important. Promoting urban garden biodiversity requires that larger vegetated properties be supported and encouraged, and that planners should consider biodiversity when formulating policies, concerning garden size, property size, and consents that may result in a progressive increase in the proportion of built over/paved areas.
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