scholarly journals Thermally controlled microfluidic back pressure regulator

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Karolina Svensson ◽  
Simon Södergren ◽  
Klas Hjort
Keyword(s):  
Large Scale ◽  
Pressure Control ◽  
Back Pressure ◽  
Dead Volume ◽  
Pressure Regulator ◽  
Total Analysis System ◽  
Elevated Pressures ◽  
Upstream Pressure ◽  
Analysis System ◽  
Pressure Changes

AbstractBy using the temperature dependence of viscosity, we introduce a novel type of microfluidic lab-on-a-chip back pressure regulator (BPR) that can be integrated into a micro-total-analysis-system. A BPR is an important component used to gain pressure control and maintain elevated pressures in e.g. chemical extractions, synthesis, and analyses. Such applications have been limited in microfluidics, since the back pressure regularly has been attained by passive restrictors or external large-scale BPRs. Herein, an active microfluidic BPR is presented, consisting of a glass chip with integrated thin-film heaters and thermal sensors. It has no moving parts but a fluid restrictor where the flow resistance is controlled by the change of viscosity with temperature. Performance was evaluated by regulating the upstream pressure of methanol or water using a PID controller. The developed BPR has the smallest reported dead volume of 3 nL and the thermal actuation has time constants of a few seconds. The pressure regulation were reproducible with a precision in the millibar range, limited by the pressure sensor. The time constant of the pressure changes was evaluated and its dependence of the total upstream volume and the compressibility of the liquids is introduced.

scholarly journals Oil Immersed Lossless Total Analysis System (OIL-TAS): Integrated RNA Extraction and Detection for SARS-CoV-2 Testing

2020 ◽  
Author(s):  
Duane S. Juang ◽  
Terry D. Juang ◽  
Dawn M. Dudley ◽  
Christina M. Newman ◽  
Thomas C. Friedrich ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Large Scale ◽  
Rna Extraction ◽  
Cost Effective ◽  
Acid Extraction ◽  
Input Concentration ◽  
Total Analysis System ◽  
Total Analysis ◽  
Analysis System ◽  
Disease Testing

AbstractThe coronavirus disease 2019 (COVID-19) pandemic exposed difficulties in scaling current quantitative PCR (qPCR)-based diagnostic methodologies for large-scale infectious disease testing. Bottlenecks include the lengthy multi-step process of nucleic acid extraction followed by qPCR readouts, which require costly instrumentation and infrastructure, as well as reagent and plastic consumable shortages stemming from supply chain constraints. Here we report a novel Oil Immersed Lossless Total Analysis System (OIL-TAS), which integrates RNA extraction and detection onto a single device that is simple, rapid, cost effective, uses minimal supplies and requires reduced infrastructure to perform. We validated the performance of OIL-TAS using contrived samples containing inactivated SARS-CoV-2 viral particles, which show that the assay can reliably detect an input concentration of 10 copies/μL and sporadically detect down to 1 copy/μL. The OIL-TAS method can serve as a faster, cheaper, and easier-to-deploy alternative to current qPCR-based methods for infectious disease testing.

scholarly journals Oil immersed lossless total analysis system for integrated RNA extraction and detection of SARS-CoV-2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Duane S. Juang ◽  
Terry D. Juang ◽  
Dawn M. Dudley ◽  
Christina M. Newman ◽  
Molly A. Accola ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Large Scale ◽  
Rna Extraction ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Acid Extraction ◽  
Total Analysis System ◽  
Total Analysis ◽  
Analysis System ◽  
Disease Testing

AbstractThe COVID-19 pandemic exposed difficulties in scaling current quantitative PCR (qPCR)-based diagnostic methodologies for large-scale infectious disease testing. Bottlenecks include lengthy multi-step processes for nucleic acid extraction followed by qPCR readouts, which require costly instrumentation and infrastructure, as well as reagent and plastic consumable shortages stemming from supply chain constraints. Here we report an Oil Immersed Lossless Total Analysis System (OIL-TAS), which integrates RNA extraction and detection onto a single device that is simple, rapid, cost effective, and requires minimal supplies and infrastructure to perform. We validated the performance of OIL-TAS using contrived SARS-CoV-2 viral particle samples and clinical nasopharyngeal swab samples. OIL-TAS showed a 93% positive predictive agreement (n = 57) and 100% negative predictive agreement (n = 10) with clinical SARS-CoV-2 qPCR assays in testing clinical samples, highlighting its potential to be a faster, cheaper, and easier-to-deploy alternative for infectious disease testing.

scholarly journals Algorithmic Transparency of Large-Scale *AIDA Programs

2020 ◽  
Vol 30 (09) ◽  
pp. 1263-1288
Author(s):  
Yutaka Watanobe ◽  
Nikolay Mirenkov
Keyword(s):  
Data Structures ◽  
Large Scale ◽  
Software Systems ◽  
Computational Algorithms ◽  
Computer Language ◽  
Algorithms And Data Structures ◽  
Application Methods ◽  
Analysis System ◽  
Computational Comparison

Programming in pictures is an approach where pictures and moving pictures are used as super-characters to represent the features of computational algorithms and data structures, as well as for explaining the models and application methods involved. *AIDA is a computer language that supports programming in pictures. This language and its environment have been developed and promoted as a testbed for various innovations in information technology (IT) research and implementation, including exploring the compactness of the programs and their adaptive software systems, and obtaining better understanding of information resources. In this paper, new features of the environment and methods of their implementation are presented. They are considered within a case study of a large-scale module of a nuclear safety analysis system to demonstrate that *AIDA language is appropriate for developing efficient codes of serious applications and for providing support, based on folding/unfolding techniques, enhancing the readability, maintainability and algorithmic transparency of programs. Features of this support and the code efficiency are presented through the results of a computational comparison with a FORTRAN equivalent.

scholarly journals Large-Scale Molecular Dynamics Simulations Reveal New Insights Into the Phase Transition Mechanisms in MIL-53(Al)

2021 ◽  
Vol 9 ◽  
Author(s):  
Sander Vandenhaute ◽  
Sven M. J. Rogge ◽  
Veronique Van Speybroeck
Keyword(s):  
Large Scale ◽  
Pressure Control ◽  
Layer By Layer ◽  
Major Step ◽  
Transition Mechanism ◽  
External Pressures ◽  
Pressure Regime ◽  
Dynamics Simulations ◽  
Experimental Crystal ◽  
External Stimuli

Soft porous crystals have the ability to undergo large structural transformations upon exposure to external stimuli while maintaining their long-range structural order, and the size of the crystal plays an important role in this flexible behavior. Computational modeling has the potential to unravel mechanistic details of these phase transitions, provided that the models are representative for experimental crystal sizes and allow for spatially disordered phenomena to occur. Here, we take a major step forward and enable simulations of metal-organic frameworks containing more than a million atoms. This is achieved by exploiting the massive parallelism of state-of-the-art GPUs using the OpenMM software package, for which we developed a new pressure control algorithm that allows for fully anisotropic unit cell fluctuations. As a proof of concept, we study the transition mechanism in MIL-53(Al) under various external pressures. In the lower pressure regime, a layer-by-layer mechanism is observed, while at higher pressures, the transition is initiated at discrete nucleation points and temporarily induces various domains in both the open and closed pore phases. The presented workflow opens the possibility to deduce transition mechanism diagrams for soft porous crystals in terms of the crystal size and the strength of the external stimulus.

scholarly journals An integrated microfluidic platform for quantifying drug permeation across biomimetic vesicle membranes

2019 ◽  
Author(s):  
Michael Schaich ◽  
Jehangir Cama ◽  
Kareem Al Nahas ◽  
Diana Sobota ◽  
Kevin Jahnke ◽  
...  
Keyword(s):  
Drug Transport ◽  
Membrane Composition ◽  
Drug Permeability ◽  
Bacterial Membranes ◽  
Drug Molecules ◽  
Total Analysis System ◽  
Transport Assay ◽  
Order Of Magnitude ◽  
Analysis System ◽  
The Individual

The low membrane permeability of candidate drug molecules is a major challenge in drug development and insufficient permeability is one reason for the failure of antibiotic treatment against bacteria. Quantifying drug transport across specific pathways in living systems is challenging since one typically lacks knowledge of the exact lipidome and proteome of the individual cells under investigation. Here, we quantify drug permeability across biomimetic liposome membranes, with comprehensive control over membrane composition. We integrate the microfluidic octanol-assisted liposome assembly platform with an optofluidic transport assay to create a complete microfluidic total analysis system for quantifying drug permeability. Our system enables us to form liposomes with charged lipids mimicking the negative charge of bacterial membranes at physiological salt and pH levels, which proved difficult with previous liposome formation techniques. Furthermore, the microfluidic technique yields an order of magnitude more liposomes per experiment than previous assays. We demonstrate the feasibility of the assay by determining the permeability coefficient of norfloxacin across biomimetic liposomes.

Flexible Non-Intrusive Heat Flux Instrumentation for the AFRL Research Turbine

2011 ◽  
Author(s):  
Richard J. Anthony ◽  
John P. Clark ◽  
Stephen W. Kennedy ◽  
John M. Finnegan ◽  
Dean Johnson ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Large Scale ◽  
Thermal Loading ◽  
Pressure Sensors ◽  
Large Data ◽  
Fast Response ◽  
Data Sets ◽  
Unsteady Aerodynamic ◽  
Analysis System

This paper describes a large scale heat flux instrumentation effort for the AFRL HIT Research Turbine. The work provides a unique amount of high frequency instrumentation to acquire fast response unsteady heat flux in a fully rotational, cooled turbine rig along with unsteady pressure data to investigate thermal loading and unsteady aerodynamic airfoil interactions. Over 1200 dynamic sensors are installed on the 1 & 1/2 stage turbine rig. Airfoils include 658 double-sided thin film gauges for heat flux, 289 fast-response Kulite pressure sensors for unsteady aerodynamic measurements, and over 40 thermocouples. An overview of the instrumentation is given with in-depth focus on the non-commercial thin film heat transfer sensors designed and produced in the Heat Flux Instrumentation Laboratory at WPAFB. The paper further describes the necessary upgrade of data acquisition systems and signal conditioning electronics to handle the increased channel requirements of the HIT Research Turbine. More modern, reliable, and efficient data processing and analysis code provides better handling of large data sets and allows easy integration with the turbine design and analysis system under development at AFRL. Example data from cooled transient blowdown tests in the TRF are included along with measurement uncertainty.

Sign in / Sign up

Export Citation Format

Share Document