scholarly journals A Facile and Rapid Route to Self-Digitization of Samples into a High Density Microwell Array for Digital Bioassays

2021 ◽  
Author(s):  
Xu Cui ◽  
Tianbao Hu ◽  
Qiang Chen ◽  
Qiang Zhao ◽  
Yin Wu ◽  
...  

ABSTRACTDigital bioassays are powerful methods to detect rare analytes from complex mixtures and study the temporal processes of individual entities within biological systems. In digital bioassays, a crucial first step is the discretization of samples into a large number of identical independent partitions. Here, we developed a rapid and facile sample partitioning method for versatile digital bioassays. This method is based on a detachable self-digitization (DSD) chip which couples a reversible assembly configuration and a predegassing-based self-pumping mechanism to achieve an easy, fast and large-scale sample partitioning. The DSD chip consists of a channel layer used for loading sample and a microwell layer used for holding the sample partitions. Benefitting from its detachability, the chip avoids a lengthy oil flushing process used to remove the excess sample in loading channels and can compartmentalize a sample into more than 100,000 wells of picoliter volume with densities up to 14,000 wells/cm2 in less than 30 s. We also demonstrated the utility of the proposed method by applying it to digital PCR and digital microbial assays.

Author(s):  
Sorin Comorosan ◽  
Silviu Polosan ◽  
Marian Apostol ◽  
Irinel Popescu ◽  
Ileana Farcasanu ◽  
...  

2018 ◽  
Vol 12 (12) ◽  
pp. 2266-2276
Author(s):  
Jing Liu ◽  
Chengpan Li ◽  
Shaohui Cheng ◽  
Shengnan Ya ◽  
Dayong Gao ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3069
Author(s):  
Zheng Liu ◽  
Ling Lin ◽  
Haozhe Zhu ◽  
Zhongyuan Wu ◽  
Xi Ding ◽  
...  

Muscle stem cells (MuSCs) isolated ex vivo are essential original cells to produce cultured meat. Currently, one of the main obstacles for cultured meat production derives from the limited capacity of large-scale amplification of MuSCs, especially under high-density culture condition. Here, we show that at higher cell densities, proliferation and differentiation capacities of porcine MuSCs are impaired. We investigate the roles of Hippo-YAP signaling, which is important regulators in response to cell contact inhibition. Interestingly, abundant but not functional YAP proteins are accumulated in MuSCs seeded at high density. When treated with lysophosphatidic acid (LPA), the activator of YAP, porcine MuSCs exhibit increased proliferation and elevated differentiation potential compared with control cells. Moreover, constitutively active YAP with deactivated phosphorylation sites, but not intact YAP, promotes cell proliferation and stemness maintenance of MuSCs. Together, we reveal a potential molecular target that enables massive MuSCs expansion for large-scale cultured meat production under high-density condition.


2021 ◽  
Author(s):  
◽  
Yingyi Zhang

<p>Parametric tools have been broadly implemented in Architecture, Engineering and Construction (AEC) industry. Recently, an increasing volume of research finds that parametric tools also have the capability to facilitate large-scale planning and urban design. Much of this research, however, focuses on parametric representation or environment simulation. There is insufficient research about using parametric tools to enhance urban regulation. Parametric tools can provide smart design procedures by integrating strategies, solutions and expressions in one system. They may allow alternative approaches to urban regulation that conventional tools do not process.  This research aims to create a parametric modelling system to aid urban regulation. The system offers a visualised coding interface to manipulate parameters and achieve interactive performance feedback at the early stage of urban regulation. Form-Based Code uses the modelling system in this research. It generates a specific morphology by controlling physical form with less focus on land use. With the rise of New Urbanism, Form-Based Code has been used in various American regulation projects. This research extends the application of Form-Based Code, adopting it for urban-peripheral environments outside of the USA. High-density cities where provide the volumetric morphology context is important for this work. Tsim Sha Tsui area of Hong Kong works as an experimental site.  The feasibility of parametric urban regulation is examined by developing a parametric modelling system for Form-Based Code in Hong Kong. Understanding the site’s form characteristics, the transect matrix of Form-Based Code is expanded by incorporating multi-layered zone types and regulating plans. Embedding the zones into parametric modelling software Rhinoceros 3D and Grasshopper 3D, a regenerative prototype works to create real-time scenarios responding to parameters, rules and geometry constraints. The results of parametric urban regulation are evaluated by both Form-Based Code standards and local urban regulation standards to assess its feasibility in context.  This research demonstrates that the parametric modelling system for Form-Based Code has both technological and implemental potential to work as an alternative approach to urban regulation, especially in complex developments. Form complexity is a reflection of sophisticated human-society systems and the sequential evolution of a dynamic morphology. Form-Based Code is enhanced by the parametric modelling system to describe and regulate form complexity in a logical manner. Additionally, although parametric Form-Based Code processing is based on the original Form-Based Code, it is not limited to that. Describing urban regulation with visualised models bridges specialists and the public in community demonstrations and code assembling. The parametric modelling system has a positive impact on resolving challenges, predicting outcomes, and applying urban regulation innovation to the volumetric morphology of high-density cities in Asia.</p>


1996 ◽  
Vol 22 (1-3) ◽  
pp. 65-78 ◽  
Author(s):  
David R. Gray ◽  
Su Chen ◽  
William Howarth ◽  
Duane Inlow ◽  
Brian L. Maiorella

Author(s):  
Qinqing Kang

Node self-positioning is one of the supporting technologies for wireless sensor network applications. In this paper, a clustering localization algorithm is proposed for large-scale high-density wireless sensor networks. Firstly, the potential of the node is defined as the basis for the election of the cluster head. The distance between the nodes in the network is calculated indirectly by the relationship between the received signal strength and the communication radius. The topology information in each cluster is saved by the cluster head, and the linear programming method is used in the cluster head to implement the cluster internal relative positioning. Then, from the sink node, the inter-cluster location fusion is gradually implemented, and finally the absolute positioning of the whole network is realized. Compared with the centralized convex programming algorithm, the proposed algorithm has low computational complexity, small traffic, high positioning accuracy, and does not need to know the signal attenuation factor in the environment in advance, and there is anti-noise ability.


1988 ◽  
Vol 130 ◽  
pp. 259-271
Author(s):  
Carlos S. Frenk

Modern N-body techniques allow the study of galaxy formation in the wider context of the formation of large-scale structure in the Universe. The results of such a study within the cold dark matter cosmogony are described. Dark galactic halos form at relatively recent epochs. Their properties and abundance are similar to those inferred for the halos of real galaxies. Massive halos tend to form preferentially in high density regions and as a result the galaxies that form within them are significantly more clustered than the underlying mass. This natural bias may be strong enough to reconcile the observed clustering of galaxies with the assumption that Ω = 1.


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