Microfluidic Gas Sensing with Living Microbial Cells Confined in a Microaquarium

2013 ◽  
Vol 543 ◽  
pp. 431-434 ◽  
Author(s):  
Kazunari Ozasa ◽  
Jee Soo Lee ◽  
Simon Song ◽  
Masahiko Hara ◽  
Mizuo Maeda
Keyword(s):  
Real Time ◽  
Concentration Gradient ◽  
Gas Sensing ◽  
Bacterial Chemotaxis ◽  
Optical Microscope ◽  
Sensor Chip ◽  
Microfluidic Channels ◽  
Microbial Cells ◽  
Gas Molecules ◽  
On Chip

We investigated on-chip cytotoxicity gas sensing using the bacterial chemotaxis of Euglena confined in a microaquarium. The sensor chip made from PDMS had one microaquarium and two microfluidic channels passing aside of the microaquarium. The chemotactic microbial cells were confined in the microaquarium, whereas two gases (one sample and one reference) flowed in the two isolated microchannels. Gas molecules move from the microchannels into the microaquarium by permeation through porous PDMS wall, and dissolve into the water in the microaquarium, where Euglena cells are swimming. The chemotactic movements of Euglena were observed with an optical microscope and measured as traces in real time. By injecting CO2 and air into each microchannel separately, the Euglena cells in the microaquarium moved to air side, escaping from CO2. This observation showed that the concentration gradient of CO2 was produced in the water in the microaquarium. The CO2-avoiding movement of Euglena was increased largely at a CO2 concentration of 40%, and then moderately increased above 60%. Some Euglena cells stopped swimming at the air side of the microaquarium and remained there even after CO2 has been removed, which can be used as the indicator of CO2 history.

sbRIO Lab–On–Chip Gas Sensing and Monitoring for Multisensory Array

2013 ◽  
Vol 61 (2) ◽  
Author(s):  
Siti Noradhlia Mohamad Tukijan ◽  
Mohd Azhar Abdul Razak ◽  
Fauzan Khairi Che Harun
Keyword(s):  
Response Time ◽  
Real Time ◽  
Virtual Instrument ◽  
Room Temperature ◽  
Gas Sensing ◽  
Fast Response ◽  
Lab On Chip ◽  
Flow Through ◽  
On Chip ◽  
Early Preparation

It is utmost to create a system at which can monitor and indicate the gas level exist in certain area, especially for hazardous gas, as early preparation and protection before something worst happen. The gas sensing and monitoring system composes of hardware and software elements. A spiral chamber which is simplified on chip, known as Lab–On–Chip (LOC), plays an important role in this system. The examined gases will be analysed by 16 sensors during the flow through the spiral chamber. The responses of these sensors are obtained via analogue input channels from single board RIO (sbRIO) and are displayed on a computer using LabVIEW virtual instrument software. The system offers portable, real–time monitoring and fast response time even in room temperature.

Principles of Low-Vacuum SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1304-1305
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
New Technologies ◽  
High Vacuum ◽  
Optical Microscope ◽  
Specimen Surface ◽  
Electrical Field ◽  
Gaseous Environment ◽  
New Information ◽  
Gas Molecules ◽  
New Interactions ◽  
Gas Pressures

Only recently it became possible to expand scanning electron microscopy to low vacuum and atmospheric pressure through the introduction of several new technologies. In principle, only the specimen is provided with a controlled gaseous environment while the optical microscope column is kept at high vacuum. In the specimen chamber, the gas can generate new interactions with i) the probe electrons, ii) the specimen surface, and iii) the specimen-specific signal electrons. The results of these interactions yield new information about specimen surfaces not accessible to conventional high vacuum SEM. Several microscope types are available differing from each other by the maximum available gas pressure and the types of signals which can be used for investigation of specimen properties.Electrical non-conductors can be easily imaged despite charge accumulations at and beneath their surface. At high gas pressures between 10-2 and 2 torr, gas molecules are ionized in the electrical field between the specimen surface and the surrounding microscope parts through signal electrons and, to a certain extent, probe electrons. The gas provides a stable ion flux for a surface charge equalization if sufficient gas ions are provided.

Adsorption of the Gas Molecules (NH3, C2H6O, C3H6O, CO, H2S) on noble metal (Ag, Au, Pt, Pd, Ru)–Doped MoSe2 Monolayer: A First-Principles Study

2021 ◽  
Author(s):  
Lanjuan Zhou ◽  
Sujing Yu ◽  
Yan Yang ◽  
Qi Li ◽  
Tingting Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Noble Metal ◽  
First Principles ◽  
Density Functional ◽  
Noble Metals ◽  
Gas Sensing ◽  
Functional Theory ◽  
First Principles Study ◽  
Gas Molecules ◽  
Sensing Performance

In this paper, the effects of five noble metals (Au, Pt, Pd, Ag, Ru) doped MoSe2 on improving gas sensing performance were predicted through density functional theory (DFT) based on...

scholarly journals Design Methodology of Passive In-Line Relays for Molecular Communication in Flow-Induced Microfluidic Channel

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 65
Author(s):  
Puneet Manocha ◽  
Gitanjali Chandwani
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Microfluidic Channel ◽  
Microfluidic Channels ◽  
Molecular Communication ◽  
External Energy ◽  
Lab On Chip ◽  
Molecular Communication Systems ◽  
Macro Scale ◽  
On Chip

Molecular communication is a bioinspired communication that enables macro-scale, micro-scale and nano-scale devices to communicate with each other. The molecular communication system is prone to severe signal attenuation, dispersion and delay, which leads to performance degradation as the distance between two communicating devices increases. To mitigate these challenges, relays are used to establish reliable communication in microfluidic channels. Relay assisted molecular communication systems can also enable interconnection among various entities of the lab-on-chip for sharing information. Various relaying schemes have been proposed for reliable molecular communication systems, most of which lack practical feasibility. Thus, it is essential to design and develop relays that can be practically incorporated into the microfluidic channel. This paper presents a novel design of passive in-line relay for molecular communication system that can be easily embedded in the microfluidic channel and operate without external energy. Results show that geometric modification in the microfluidic channel can act as a relay and restore the degraded signal up-to 28%.

scholarly journals On-Device Deep Learning Inference for System-on-Chip (SoC) Architectures

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 689
Author(s):  
Tom Springer ◽  
Elia Eiroa-Lledo ◽  
Elizabeth Stevens ◽  
Erik Linstead
Keyword(s):  
Machine Learning ◽  
Deep Learning ◽  
Real Time ◽  
Operating Systems ◽  
System On Chip ◽  
Low Latency ◽  
Management Framework ◽  
On Chip ◽  
Specialized Hardware ◽  
Deterministic Behavior

As machine learning becomes ubiquitous, the need to deploy models on real-time, embedded systems will become increasingly critical. This is especially true for deep learning solutions, whose large models pose interesting challenges for target architectures at the “edge” that are resource-constrained. The realization of machine learning, and deep learning, is being driven by the availability of specialized hardware, such as system-on-chip solutions, which provide some alleviation of constraints. Equally important, however, are the operating systems that run on this hardware, and specifically the ability to leverage commercial real-time operating systems which, unlike general purpose operating systems such as Linux, can provide the low-latency, deterministic execution required for embedded, and potentially safety-critical, applications at the edge. Despite this, studies considering the integration of real-time operating systems, specialized hardware, and machine learning/deep learning algorithms remain limited. In particular, better mechanisms for real-time scheduling in the context of machine learning applications will prove to be critical as these technologies move to the edge. In order to address some of these challenges, we present a resource management framework designed to provide a dynamic on-device approach to the allocation and scheduling of limited resources in a real-time processing environment. These types of mechanisms are necessary to support the deterministic behavior required by the control components contained in the edge nodes. To validate the effectiveness of our approach, we applied rigorous schedulability analysis to a large set of randomly generated simulated task sets and then verified the most time critical applications, such as the control tasks which maintained low-latency deterministic behavior even during off-nominal conditions. The practicality of our scheduling framework was demonstrated by integrating it into a commercial real-time operating system (VxWorks) then running a typical deep learning image processing application to perform simple object detection. The results indicate that our proposed resource management framework can be leveraged to facilitate integration of machine learning algorithms with real-time operating systems and embedded platforms, including widely-used, industry-standard real-time operating systems.

scholarly journals Design of a Real-Time Breakdown Voltage and On-Chip Temperature Monitoring System for Single Photon Avalanche Diodes

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 25
Author(s):  
Shijie Deng ◽  
Alan P. Morrison ◽  
Yong Guo ◽  
Chuanxin Teng ◽  
Ming Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Breakdown Voltage ◽  
Count Rate ◽  
Single Photon ◽  
Photon Counting ◽  
Temperature Monitoring ◽  
Dark Count ◽  
Chip Temperature ◽  
Avalanche Diodes ◽  
On Chip

The design and implementation of a real-time breakdown voltage and on-chip temperature monitoring system for single photon avalanche diodes (SPADs) is described in this work. In the system, an on-chip shaded (active area of the detector covered by a metal layer) SPAD is used to provide a dark count rate for the breakdown voltage and temperature calculation. A bias circuit was designed to provide a bias voltage scanning for the shaded SPAD. A microcontroller records the pulses from the anode of the shaded SPAD and calculates its real-time dark count rate. An algorithm was developed for the microcontroller to calculate the SPAD’s breakdown voltage and the on-chip temperature in real time. Experimental results show that the system is capable of measuring the SPAD’s breakdown voltage with a mismatch of less than 1.2%. Results also show that the system can provide real-time on-chip temperature monitoring for the range of −10 to 50 °C with errors of less than 1.7 °C. The system proposed can be used for the real-time SPAD’s breakdown voltage and temperature estimation for dual-SPADs or SPAD arrays chip where identical detectors are fabricated on the same chip and one or more dummy SPADs are shaded. With the breakdown voltage and the on-chip temperature monitoring, intelligent control logic can be developed to optimize the performance of the SPAD-based photon counting system by adjusting the parameters such as excess bias voltage and dead-time. This is particularly useful for SPAD photon counting systems used in complex working environments such as the applications in 3D LIDAR imaging for geodesy, geology, geomorphology, forestry, atmospheric physics and autonomous vehicles.

All-nanoparticle layer-by-layer coatings for Mid-IR on-chip gas sensing

2020 ◽  
Vol 56 (91) ◽  
pp. 14283-14286
Author(s):  
Diana Al Husseini ◽  
Junchao Zhou ◽  
Daniel Willhelm ◽  
Trevor Hastings ◽  
Gregory S. Day ◽  
...  
Keyword(s):  
Optical Waveguides ◽  
Gas Sensing ◽  
Layer By Layer ◽  
Precise Control ◽  
Nanoparticle Layer ◽  
Withdrawal Speed ◽  
Layer Deposition ◽  
Nanoparticle Coatings ◽  
On Chip

Functionalization of optical waveguides with submicron all-nanoparticle coatings significantly enhanced the detection of acetone. Such coatings were enabled via precise control of the substrate withdrawal speed using the layer-by-layer deposition.

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