Characterization of Microscale Particles Using a Microfluidic Flow Cytometer Equipped With a Multi-Plex Photon Counter

2013 ◽  
Author(s):  
Pouya Asrar ◽  
Nastaran Hashemi
Keyword(s):  
Integrated Optics ◽  
Scattered Light ◽  
Photon Counting ◽  
High Gain ◽  
Flow Cytometer ◽  
Photon Counter ◽  
Microfluidic Flow ◽  
Compact Size ◽  
Using Data ◽  
New Generation

We have shown the design and fabrication of a microfluidic flow cytometer. The microfluidic flow cytometer has been used to characterize microspheres of different sizes. The device is consisted of a microchannel, electronics, and integrated optics. The microchannel has three inlets. Two inlets are used to introduce sheath flows and one middle inlet is assigned as sample inlet. The sample flow is hydrodynamically focused at the center of the microchannel by two side streams (sheath flows). Also arrays of four chevron grooves compress the sample flow from the top and bottom of the microchannel. The core flow contains microspheres at a certain concentration. Detection of the microspheres at the interrogation region of the channel is performed by integrated optics and electronics. The scattered light emitted from the microspheres is collected by a multi-plex photo diode (MPPC). The results are recorded using data acquisition (DAQ) unit. The MPPCs employed in the setup is the new generation of photon counter devices with an excellent detection limit, a compact size, and capability of recording data at high gain compared to previous generation of photodetectors such as photomultipliers or avalanche photon diodes. The flow cytometer was sensitive enough to collect data from 3 μm microspheres using such mentioned sensitive photon counting unit. We have also used COMSOL Multiphysics software to investigate velocity and pressure distribution as well as concentration distribution along the microchannel. The average voltage collected by MPPC was 1.9 V for 10.2 μm and 1.6 V for 3.2 μm microsphere.

scholarly journals A 300-GHz low-cost high-gain fully metallic Fabry–Perot cavity antenna for 6G terahertz wireless communications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Basem Aqlan ◽  
Mohamed Himdi ◽  
Hamsakutty Vettikalladi ◽  
Laurent Le-Coq
Keyword(s):  
Communication Systems ◽  
Low Cost ◽  
Frequency Selective Surface ◽  
High Gain ◽  
Wireless Communication Systems ◽  
Beam Radiation ◽  
Compact Size ◽  
Fabry Perot ◽  
Operating Bandwidth ◽  
Polarization Level

AbstractA low-cost, compact, and high gain Fabry–Perot cavity (FPC) antenna which operates at 300 GHz is presented. The antenna is fabricated using laser-cutting brass technology. The proposed antenna consists of seven metallic layers; a ground layer, an integrated stepped horn element (three-layers), a coupling layer, a cavity layer, and an aperture-frequency selective surface (FSS) layer. The proposed aperture-FSS function acts as a partially reflective surface, contributing to a directive beam radiation. For verification, the proposed sub-terahertz (THz) FPC antenna prototype was developed, fabricated, and measured. The proposed antenna has a measured reflection coefficient below − 10 dB from 282 to 304 GHz with a bandwidth of 22 GHz. The maximum measured gain observed is 17.7 dBi at 289 GHz, and the gain is higher than 14.4 dBi from 285 to 310 GHz. The measured radiation pattern shows a highly directive pattern with a cross-polarization level below − 25 dB over the whole band in all cut planes, which confirms with the simulation results. The proposed antenna has a compact size, low fabrication cost, high gain, and wide operating bandwidth. The total height of the antenna is 1.24 $${\lambda }_{0}$$ λ 0 ($${\lambda }_{0}$$ λ 0 at the design frequency, 300 GHz) , with a size of 2.6 mm × 2.6 mm. The proposed sub-THz waveguide-fed FPC antenna is suitable for 6G wireless communication systems.

Photon-counting microcolorimeter with 40-nl cuvette

1991 ◽  
Vol 261 (1) ◽  
pp. F203-F206
Author(s):  
T. L. Pallone
Keyword(s):  
Lower Limit ◽  
Plasma Volume ◽  
Fiber Optic ◽  
Limit Of Detection ◽  
Photon Counting ◽  
Injection Port ◽  
Photon Counter ◽  
Sample Injection ◽  
Lowry Assay

A colorimeter with a 40-nl cuvette has been constructed. The wall of standard capillary glass was perforated to produce a sample injection port. A section of the capillary glass was drawn to a length of 1/2 cm and 80 microns ID by heating on a microforge. This produced a cuvette volume of approximately 40 nl. Two fiber-optic filaments, 80 microns in diameter, were fixed into the cuvette to transmit and receive light from the sample. The output of the colorimeter was measured with a microscope photon-counting detection assembly. It has been shown that the colorimeter enables a reduction of the plasma volume requirements of the Lowry microprotein assay from several nanoliters to 60 pl. The linearity and reproducibility of the microcolorimeter when used with the Lowry assay has been verified. The colorimeter output is several orders of magnitude above the lower limit of detection of the photon counter.

Understanding the Links between Mentoring and Self-Efficacy in the New Generation of Women STEM Scholars

2010 ◽  
pp. 97-117 ◽  
Author(s):  
Elizabeth Yost ◽  
Donna M. Handley ◽  
Shelia R. Cotten ◽  
Vicki Winstead
Keyword(s):  
Self Efficacy ◽  
Mentoring Programs ◽  
National Study ◽  
Stem Fields ◽  
New Faculty ◽  
Gender Inequity ◽  
Mentoring Practices ◽  
Using Data ◽  
New Generation ◽  
The Impact

American colleges and universities are in need of innovative approaches to recruit and retain the upcoming generation of new faculty members. Specifically within the STEM (Science, Technology, Engineering, and Math) fields, there is an additional need to focus on meeting the needs of women in order to begin to address gender inequity within STEM. This chapter examines the impact of mentoring on self-efficacy for female graduate students and post doctoral fellows in STEM fields. Using data from a national study of selected U.S. academic institutions, recommendations are made in order to enhance mentoring practices that will reduce the barriers women face within STEM fields. Quality mentoring programs represent a viable way to enhance institutional change that may result in increased numbers of women in STEM fields.

scholarly journals Validation of ICESat-2 ATLAS Bathymetry and Analysis of ATLAS’s Bathymetric Mapping Performance

2019 ◽  
Vol 11 (14) ◽  
pp. 1634 ◽  
Author(s):  
Christopher E. Parrish ◽  
Lori A. Magruder ◽  
Amy L. Neuenschwander ◽  
Nicholas Forfinski-Sarkozi ◽  
Michael Alonzo ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Photon Counting ◽  
Water Clarity ◽  
Virgin Islands ◽  
Maximum Depth ◽  
Laser Altimeter ◽  
Bathymetric Mapping ◽  
Primary Focus ◽  
Using Data ◽  
Water Depths

NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) was launched in September, 2018. The satellite carries a single instrument, ATLAS (Advanced Topographic Laser Altimeter System), a green wavelength, photon-counting lidar, enabling global measurement and monitoring of elevation with a primary focus on the cryosphere. Although bathymetric mapping was not one of the design goals for ATLAS, pre-launch work by our research team showed the potential to map bathymetry with ICESat-2, using data from MABEL (Multiple Altimeter Beam Experimental Lidar), NASA’s high-altitude airborne ATLAS emulator, and adapting the laser-radar equation for ATLAS specific parameters. However, many of the sensor variables were only approximations, which limited a full assessment of the bathymetric mapping capabilities of ICESat-2 during pre-launch studies. Following the successful launch, preliminary analyses of the geolocated photon returns have been conducted for a number of coastal sites, revealing several salient examples of seafloor detection in water depths of up to ~40 m. The geolocated seafloor photon returns cannot be taken as bathymetric measurements, however, since the algorithm used to generate them is not designed to account for the refraction that occurs at the air–water interface or the corresponding change in the speed of light in the water column. This paper presents the first early on-orbit validation of ICESat-2 bathymetry and quantification of the bathymetric mapping performance of ATLAS using data acquired over St. Thomas, U.S. Virgin Islands. A refraction correction, developed and tested in this work, is applied, after which the ICESat-2 bathymetry is compared against high-accuracy airborne topo-bathymetric lidar reference data collected by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). The results show agreement to within 0.43—0.60 m root mean square error (RMSE) over 1 m grid resolution for these early on-orbit data. Refraction-corrected bottom return photons are then inspected for four coastal locations around the globe in relation to Visible Infrared Imaging Radiometer Suite (VIIRS) Kd(490) data to empirically determine the maximum depth mapping capability of ATLAS as a function of water clarity. It is demonstrated that ATLAS has a maximum depth mapping capability of nearly 1 Secchi in depth for water depths up to 38 m and Kd(490) in the range of 0.05–0.12 m−1. Collectively, these results indicate the great potential for bathymetric mapping with ICESat-2, offering a promising new tool to assist in filling the global void in nearshore bathymetry.

Microfluidic Flow Cytometer for Multiparameter Screening of Fluorophore Photophysics

CLEO: 2014 ◽  
2014 ◽  
Author(s):  
Kevin M. Dean ◽  
Lloyd M. Davis ◽  
Jennifer L. Lubbeck ◽  
Premashis Manna ◽  
Amy E. Palmer ◽  
...  
Keyword(s):  
Flow Cytometer ◽  
Microfluidic Flow

High-speed photon-counting x-ray computed tomography system utilizing a multipixel photon counter

2009 ◽  
Author(s):  
Eiichi Sato ◽  
Toshiyuki Enomoto ◽  
Manabu Watanabe ◽  
Keitaro Hitomi ◽  
Kiyomi Takahashi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Speed ◽  
Photon Counting ◽  
Photon Counter ◽  
X Ray ◽  
Tomography System ◽  
X Ray Computed
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