Surface Design for Precise Control of Spatial Growth of a Mesostructured Inorganic/Organic Film on a Large-Scale Area

Langmuir ◽  
2007 ◽  
Vol 23 (6) ◽  
pp. 3265-3272 ◽  
Author(s):  
Atsushi Hozumi ◽  
Satoshi Kojima ◽  
Shusaku Nagano ◽  
Takahiro Seki ◽  
Naoto Shirahata ◽  
...  
Keyword(s):  
Large Scale ◽  
Organic Film ◽  
Surface Design ◽  
Precise Control ◽  
Spatial Growth

Scalable Microfluidic Platform for Flexible Configuration of and Experiments with Microtissue Multiorgan Models

2018 ◽  
Vol 24 (1) ◽  
pp. 79-95 ◽  
Author(s):  
Christian Lohasz ◽  
Nassim Rousset ◽  
Kasper Renggli ◽  
Andreas Hierlemann ◽  
Olivier Frey
Keyword(s):  
Large Scale ◽  
Plastic Material ◽  
Microtiter Plate ◽  
Scale Production ◽  
Experimental Conditions ◽  
Precise Control ◽  
Open Design ◽  
Gravity Driven ◽  
Gravity Driven Flow

Microphysiological systems hold the promise to increase the predictive and translational power of in vitro substance testing owing to their faithful recapitulation of human physiology. However, the implementation of academic developments in industrial settings remains challenging. We present an injection-molded microfluidic microtissue (MT) culture chip that features two channels with 10 MT compartments each and that was designed in compliance with microtiter plate standard formats. Polystyrene as a chip material enables reliable, large-scale production and precise control over experimental conditions due to low adsorption or absorption of small, hydrophobic molecules at or into the plastic material in comparison with predecessor chips made of polydimethylsiloxane. The chip is operated by tilting, which actuates gravity-driven flow between reservoirs at both ends of every channel, so that the system does not require external tubing or pumps. The flow rate can be modulated by adjusting the tilting angle on demand. The top-open design of the MT compartment enables efficient MT loading using standard or advanced pipetting equipment, ensures oxygen availability in the chip, and allows for high-resolution imaging. Every channel can be loaded with up to 10 identical or different MTs, as demonstrated by culturing liver and tumor MTs in the same medium channel on the chip.

How Purely Wind-Driven Long Planetary Geostrophic Waves May Be Energized in the Western Part of Ocean Subtropical Gyres

2007 ◽  
Vol 37 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Ivana Cerovečki ◽  
Roland de Szoeke
Keyword(s):  
Large Scale ◽  
Satellite Observations ◽  
Subtropical Gyre ◽  
Background Flow ◽  
Flow Perturbation ◽  
Spatial Growth ◽  
Unstable Solutions ◽  
Annual Frequency ◽  
Spatially Varying ◽  
Annual Period

Abstract Satellite observations and idealized numerical studies reveal intensification of long-period (on the order of one cycle per year) waves in the western part of ocean basins. The authors explore the idea that the intensification is associated with the spatial growth of purely time periodic, but baroclinically unstable, motions. The framework is a simple idealized 2½-layer model in which only the upper layer is directly forced by the wind, a setting similar to the shadow zone of the Luyten–Pedlosky–Stommel (LPS) model. The upper two layers participate in the wave motion, which is driven by a large-scale wind stress fluctuating with the annual period, representing the seasonal cycle. Although possibly unstable solutions exist everywhere in the subtropical gyre on account of the nonzero meridional background flow, they are not seen in the eastern part of the basin in satellite observations nor are they excited there by model gyre-scale annual-period winds. Instead, energy injected into the model ocean at a fixed frequency and with zonal and meridional wavenumbers, such that the resulting flow perturbation is locally stable, refracts westward as it propagates through the spatially varying background flow without change of frequency and reaches distant regions where the spatial wavenumber becomes complex so that spatial growth occurs. This process results in spatially growing solutions of annual or near-annual frequency only in the southwestern part of the model subtropical gyre, thus explaining why the intensification is preferentially manifested in the southwestern subtropical gyre in published numerical model results. The paper concludes with a discussion of relevant satellite and in situ observations.

scholarly journals ViSpa (Vision Spaces): A computer-vision-based representation system for individual images and concept prototypes, with large-scale evaluation

2021 ◽  
Author(s):  
Fritz Guenther ◽  
Marco Marelli ◽  
Sam Tureski ◽  
Marco A. Petilli
Keyword(s):  
Large Scale ◽  
Error Rates ◽  
Behavioral Data ◽  
Wide Audience ◽  
Precise Control ◽  
Processing Times ◽  
On Line ◽  
Image Pairs ◽  
Distributional Semantic Models ◽  
Visual Domain

Quantitative, data-driven models for mental representations have long enjoyed popularity and success in psychology (for example, distributional semantic models in the language domain), but have largely been missing for the visual domain. To overcome this, we present ViSpa (Vision Spaces), high-dimensional vector spaces that include vision-based representation for naturalistic images as well as concept prototypes. These vectors are derived directly from visual stimuli through a deep convolutional neural network (DCNN) trained to classify images, and allow us to compute vision-based similarity scores between any pair of images and/or concept prototypes. We successfully evaluate these similarities against human behavioral data in a series of large-scale studies, including off-line judgments – visual similarity judgments for the referents of word pairs (Study 1) and for image pairs (Study 2), and typicality judgments for images given a label (Study 3) – as well as on-line processing times and error rates in a discrimination (Study 4) and priming task (Study 5) with naturalistic image material. ViSpa similarities predict behavioral data across all tasks, which renders ViSpa a theoretically appealing model for vision-based representations and a valuable research tool for data analysis and the construction of experimental material: ViSpa allows for precise control over experimental material consisting of images (also in combination with words), and introduces a specifically vision-based similarity for word pairs. To make ViSpa available to a wide audience, this article a) includes (video) tutorials on how to use ViSpa in R, and b) presents a user-friendly web interface at http://vispa.fritzguenther.de.

scholarly journals A Research Method for Semi-Automated Large-Scale Cultivation of Maize to Full Maturity in an Artificial Environment

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1898
Author(s):  
Matthew Wiethorn ◽  
Chad Penn ◽  
James Camberato
Keyword(s):  
Light Intensity ◽  
Large Scale ◽  
Maize Yield ◽  
Nutrient Concentrations ◽  
Shoot Biomass ◽  
Plant Responses ◽  
Precise Control ◽  
Advantages And Disadvantages ◽  
Artificial Environment ◽  
Maize Plants

There are unique advantages and disadvantages to using the field, greenhouse, growth chamber, and media-less techniques for growing maize (Zea mays L.) for research purposes. Soil-buffered nutrients such as phosphorus (P) do not allow for precise control of solution concentrations in the field, while greenhouses, growth chambers, and hydroponics provide limiting conditions. The objectives of this study were to develop a practical technique for productively cultivating several maize plants from seed to physiological maturity (R6) in a grow room environment, with precise control of nutrient availability and timing, and evaluate its utility for the purpose of measuring plant responses to variations in nutrient concentrations. The construction and testing of a semi-automated grow room for conducting nutrient studies on 96 maize plants utilizing simulated or artificial conditions are described. Plant growth response to a range of solution phosphorus (P) concentrations was tested to evaluate the utility of the technique. Maize yield components were measured and compared to values for field-grown plants. Due to ideal conditions and successful simulation of light intensity, diurnal fluctuations in temperature and RH, and changing photoperiod, grain yield and tissue nutrient concentrations were comparable to field-grown maize, although with greater shoot biomass. Plants responded positively to increased P concentrations in fertigation. The technique can be used for large-scale plant nutrient studies that require precise control of bioavailability and timing as well as manipulation of light intensity and photoperiod duration.

scholarly journals A Robust Metatranscriptomic Technology for Population-Scale Studies of Diet, Gut Microbiome, and Human Health

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Andrew Hatch ◽  
James Horne ◽  
Ryan Toma ◽  
Brittany L. Twibell ◽  
Kalie M. Somerville ◽  
...  
Keyword(s):  
Human Health ◽  
Gut Microbiome ◽  
Large Scale ◽  
Rna Extraction ◽  
Rna Degradation ◽  
Small Scale ◽  
Sample Collection ◽  
Precise Control ◽  
Wide Range ◽  
Population Scale

A functional readout of the gut microbiome is necessary to enable precise control of the gut microbiome’s functions, which support human health and prevent or minimize a wide range of chronic diseases. Stool metatranscriptomic analysis offers a comprehensive functional view of the gut microbiome, but despite its usefulness, it has rarely been used in clinical studies due to its complexity, cost, and bioinformatic challenges. This method has also received criticism due to potential intrasample variability, rapid changes, and RNA degradation. Here, we describe a robust and automated stool metatranscriptomic method, called Viomega, which was specifically developed for population-scale studies. Viomega includes sample collection, ambient temperature sample preservation, total RNA extraction, physical removal of ribosomal RNAs (rRNAs), preparation of directional Illumina libraries, Illumina sequencing, taxonomic classification based on a database of >110,000 microbial genomes, and quantitative microbial gene expression analysis using a database of ~100 million microbial genes. We applied this method to 10,000 human stool samples and performed several small-scale studies to demonstrate sample stability and consistency. In summary, Viomega is an inexpensive, high-throughput, automated, and accurate sample-to-result stool metatranscriptomic technology platform for large-scale studies and a wide range of applications.

scholarly journals Polymer Brush Coating and Adhesion Technology at Scale

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1475 ◽  
Author(s):  
Kristian Birk Buhl ◽  
Asger Holm Agergaard ◽  
Mie Lillethorup ◽  
Jakob Pagh Nikolajsen ◽  
Steen Uttrup Pedersen ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
High Performance ◽  
Large Scale ◽  
Polymer Brush ◽  
Dissimilar Materials ◽  
Industrial Applications ◽  
Polymer Materials ◽  
Full Potential ◽  
Scale Production ◽  
Precise Control

Creating strong joints between dissimilar materials for high-performance hybrid products places high demands on modern adhesives. Traditionally, adhesion relies on the compatibility between surfaces, often requiring the use of primers and thick bonding layers to achieve stable joints. The coatings of polymer brushes enable the compatibilization of material surfaces through precise control over surface chemistry, facilitating strong adhesion through a nanometer-thin layer. Here, we give a detailed account of our research on adhesion promoted by polymer brushes along with examples from industrial applications. We discuss two fundamentally different adhesive mechanisms of polymer brushes, namely (1) physical bonding via entanglement and (2) chemical bonding. The former mechanism is demonstrated by e.g., the strong bonding between poly(methyl methacrylate) (PMMA) brush coated stainless steel and bulk PMMA, while the latter is shown by e.g., the improved adhesion between silicone and titanium substrates, functionalized by a hydrosilane-modified poly(hydroxyethyl methacrylate) (PHEMA) brush. This review establishes that the clever design of polymer brushes can facilitate strong bonding between metals and various polymer materials or compatibilize fillers or nanoparticles with otherwise incompatible polymeric matrices. To realize the full potential of polymer brush functionalized materials, we discuss the progress in the synthesis of polymer brushes under ambient and scalable industrial conditions, and present recent developments in atom transfer radical polymerization for the large-scale production of brush-modified materials.

scholarly journals Scalable Production of Monodisperse Functional Microspheres by Multilayer Parallelization of High Aspect Ratio Microfluidic Channels

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 592 ◽  
Author(s):  
Casper Ho Yin Chung ◽  
Binbin Cui ◽  
Ruyuan Song ◽  
Xin Liu ◽  
Xiaonan Xu ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Large Scale ◽  
Scale Up ◽  
Functional Materials ◽  
Droplet Microfluidics ◽  
Microfluidic Channels ◽  
Layer By Layer ◽  
Precise Control ◽  
Wide Range

Droplet microfluidics enables the generation of highly uniform emulsions with excellent stability, precise control over droplet volume, and morphology, which offer superior platforms over conventional technologies for material synthesis and biological assays. However, it remains a challenge to scale up the production of the microfluidic devices due to their complicated geometry and long-term reliability. In this study, we present a high-throughput droplet generator by parallelization of high aspect ratio rectangular structures, which enables facile and scalable generation of uniform droplets without the need to precisely control external flow conditions. A multilayer device is formed by stacking layer-by-layer of the polydimethylsiloxane (PDMS) replica patterned with parallelized generators. By feeding the sample fluid into the device immersed in the carrying fluid, we used the multilayer device with 1200 parallelized generators to generate monodisperse droplets (~45 μm in diameter with a coefficient of variation <3%) at a frequency of 25 kHz. We demonstrate this approach is versatile for a wide range of materials by synthesis of polyacrylamide hydrogel and Poly (l-lactide-co-glycolide) (PLGA) through water-in-oil (W/O) and oil-in-water (O/W) emulsion templates, respectively. The combined scalability and robustness of such droplet emulsion technology is promising for production of monodisperse functional materials for large-scale applications.

Radiotracer Diffusion Measurements of Noble Metal Atoms in Semiconducting Organic Films.

2005 ◽  
Vol 871 ◽  
Author(s):  
Michael Scharnberg ◽  
Jörn Kanzow ◽  
Klaus Rätzke ◽  
Rainer Adelung ◽  
Franz Faupel ◽  
...  
Keyword(s):  
Noble Metal ◽  
Large Scale ◽  
Field Effect Transistors ◽  
Organic Films ◽  
Organic Layer ◽  
Organic Film ◽  
Single Atoms ◽  
Metal Atoms ◽  
Diffusion Profiles ◽  
Diffusion Behaviour

AbstractThe application of organic field effect transistors (OFETs) for large scale low-cost electronic devices has lead to intense research. Diindenoperylene (DIP) thin films on SiO2 are a prominent system due to their high structural out-of-plane order. While bottom contact OFET structures can be realized easily, preparation of top contacts might cause diffusion of metal atoms (typically Ag or Au) deep into the organic film changing the injection properties at the interface. These properties are of great importance for device fabrication. Therefore, only by understanding the diffusion behaviour of metals into the organic layer, formation of well defined interfaces and control of their properties will become possible. For a better understanding of the diffusion of noble metal atoms into crystalline organic films, a radiotracer technique has been used to obtain diffusion profiles for Ag and Au diffusion in crystalline DIP films. For Ag diffusion in DIP, the decrease in Ag concentration of four orders of magnitude within the first few nanometers indicates that most of the metal atoms remain near the surface while small amounts can penetrate deep into the thin film and can even accumulate at the interface between organic film and the silicon substrate. A comparison with diffusion profiles obtained for polymers indicates that the interplay between diffusion and immobilization by aggregation also determine the diffusion behaviour of metals in organic crystalline materials. Latest experiments support this interpretation of the diffusion profiles. Single atoms are highly mobile in the organic crystalline material due to the weak interaction between the metal and the organic material. Therefore, most of the single atoms that penetrate into the material do so during the initial phase of the deposition. When more and more atoms arrive at the surface, cluster formation sets in. Due to the high cohesive energy of the metal the atoms can not leave the cluster and become immobilized. After deposition of a closed surface layer no further metal diffusion should be observed. With the knowledge about the diffusion processes gained by the radiotracer measurements control of process parameters and development of barrier layers in sub-monolayer range should be possible.

scholarly journals Constraint-based Diversification of JOP Gadgets

2021 ◽  
Vol 72 ◽  
pp. 1471-1505
Author(s):  
Rodothea Myrsini Tsoupidi ◽  
Roberto Castañeda Lozano ◽  
Benoit Baudry
Keyword(s):  
Large Scale ◽  
Distance Measure ◽  
Neighborhood Search ◽  
Software Systems ◽  
Code Size ◽  
Assembly Code ◽  
Precise Control ◽  
Application Specific ◽  
Specific Distance ◽  
Binary Programs

Modern software deployment process produces software that is uniform, and hence vulnerable to large-scale code-reuse attacks, such as Jump-Oriented Programming (JOP) attacks. Compiler-based diversification improves the resilience and security of software systems by automatically generating different assembly code versions of a given program. Existing techniques are efficient but do not have a precise control over the quality, such as the code size or speed, of the generated code variants.  This paper introduces Diversity by Construction (DivCon), a constraint-based compiler approach to software diversification. Unlike previous approaches, DivCon allows users to control and adjust the conflicting goals of diversity and code quality. A key enabler is the use of Large Neighborhood Search (LNS) to generate highly diverse assembly code efficiently. For larger problems, we propose a combination of LNS with a structural decomposition  of the problem. To further improve the diversification efficiency of DivCon against JOP attacks, we propose an application-specific distance measure tailored to the characteristics of JOP attacks.  We evaluate DivCon with 20 functions from a popular benchmark suite for embedded systems. These experiments show that DivCon's combination of LNS and our application-specific distance measure generates binary programs that are highly resilient against JOP  attacks (they share between 0.15% to 8% of JOP gadgets) with an optimality gap of 10%. Our results confirm that there is a trade-off between the quality of each assembly code version and the diversity of the entire pool of versions. In particular, the experiments  show that DivCon is able to generate binary programs that share a very small number of  gadgets, while delivering near-optimal code.  For constraint programming researchers and practitioners, this paper demonstrates that LNS is a valuable technique for finding diverse solutions. For security researchers and software  engineers, DivCon extends the scope of compiler-based diversification to performance-critical and resource-constrained applications.  

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