scholarly journals Low-cost, open-access refractive index mapping of algal cells using the transport of intensity equation

2019 ◽  
Author(s):  
Stephen Grant ◽  
Kyle Richford ◽  
Heidi Burdett ◽  
David McKee ◽  
Brian R. Patton
Keyword(s):  
Refractive Index ◽  
Biological Samples ◽  
Low Cost ◽  
Algal Species ◽  
Spatially Resolved ◽  
Potential Applications ◽  
Index Mapping ◽  
Transport Of Intensity Equation ◽  
Open Source Hardware ◽  
Species Being

AbstractPhase contrast microscopy allows stain free imaging of transparent biological samples. One technique, using the transport of intensity equation (TIE), can be performed without dedicated hardware by simply processing pairs of images taken at known spacings within the sample. The resulting TIE images are quantitative phase maps of unstained biological samples. Therefore, spatially resolved refractive index information can also be determined.Using low-cost, open-source hardware, we applied the TIE to living algal cells to measure their refractive index. We obtained refractive index values that were repeatable within species and differed by distinct amounts depending on the species being measured. We suggest TIE imaging as a method of discrimination between different algal species and, potentially, non-biological materials, based on refractive index. Potential applications in biogeochemical modelling and climate sciences are suggested.

scholarly journals Low-cost, open-access quantitative phase imaging of algal cells using the transport of intensity equation

2020 ◽  
Vol 7 (1) ◽  
pp. 191921
Author(s):  
Stephen D. Grant ◽  
Kyle Richford ◽  
Heidi L. Burdett ◽  
David McKee ◽  
Brian R. Patton
Keyword(s):  
Biological Samples ◽  
Low Cost ◽  
Algal Species ◽  
Optical Path Length ◽  
Phase Imaging ◽  
Quantitative Phase ◽  
Spatially Resolved ◽  
Potential Applications ◽  
Transport Of Intensity Equation ◽  
Open Source Hardware

Phase microscopy allows stain-free imaging of transparent biological samples. One technique, using the transport of intensity equation (TIE), can be performed without dedicated hardware by simply processing pairs of images taken at known spacings within the sample. The resulting TIE images are quantitative phase maps of unstained biological samples. Therefore, spatially resolved optical path length (OPL) information can also be determined. Using low-cost, open-source hardware, we applied the TIE to living algal cells to measure their effect on OPL. We obtained OPL values that were repeatable within species and differed by distinct amounts depending on the species being measured. We suggest TIE imaging as a method of discrimination between different algal species and, potentially, non-biological materials, based on refractive index/OPL. Potential applications in biogeochemical modelling and climate sciences are suggested.

scholarly journals Polymer Waveguide Coupled Surface Plasmon Refractive Index Sensor: A Theoretical Study

2020 ◽  
Vol 10 (4) ◽  
pp. 353-363
Author(s):  
Lanting Ji ◽  
Shuqing Yang ◽  
Rongna Shi ◽  
Yujie Fu ◽  
Juan Su ◽  
...  
Keyword(s):  
Refractive Index ◽  
Surface Plasmon ◽  
Low Cost ◽  
High Refractive Index ◽  
Waveguide Layer ◽  
Polymer Materials ◽  
Refractive Index Sensor ◽  
Polymer Waveguide ◽  
Compact Size ◽  
Potential Applications

Abstract A waveguide coupled surface plasmon sensor for detection of liquid with high refractive index (RI) is designed based on polymer materials. The effects of variation of the thickness of the Au film, polymethyl methacrylate (PMMA) buffer, and waveguide layer on the sensing performance of the waveguide are comprehensively investigated by using the finite difference method. Numerical simulations show that a thinner gold film gives rise to a more sensitive structure, while the variation of the thickness of the PMMA buffer and waveguide layer has a little effect on the sensitivity. For liquid with high RI, the sensitivity of the sensor increases significantly. When RI of liquid to be measured increases from 1.45 to 1.52, the sensitivity is as high as 4518.14nm/RIU, and a high figure of merit of 114.07 is obtained. The waveguide coupled surface plasmon RI sensor shows potential applications in the fields of environment, industry, and agriculture sensing with the merits of compact size, low cost, and high integration density.

Research Progress of Paper-Based Microfluidic Devices

2013 ◽  
Vol 421 ◽  
pp. 334-336 ◽  
Author(s):  
Yong Qiang Cheng ◽  
Cui Lian Guo ◽  
Yang Li ◽  
Bin Zhao ◽  
Xiao Cui
Keyword(s):  
Environmental Monitoring ◽  
Plasma Etching ◽  
Biological Samples ◽  
Recent Progress ◽  
Point Of Care ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Research Progress ◽  
Potential Applications

Paper-based microfluidic devices have recently received increasing attention as a potential platform for its low cost, portability and excellent compatibility with biological samples. A variety of fabrication technologies were employed, including simple photolithography, wax plotting, printing, inkjet etching, plasma etching and so on. Meanwhile, the potential applications of paper-based microfluidic devices in diagnostic, point-of-care (POC), and environmental monitoring were reported. We review the recent progress of fabrication technologies and the applications of paper-based microfluidic devices.

scholarly journals Experimental Setting for Applying Mechanical Stimuli to Study the Endothelial Response of Ex Vivo Vessels under Realistic Pathophysiological Environments

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 671
Author(s):  
Ana Osuna ◽  
Anna Ulldemolins ◽  
Hector Sanz-Fraile ◽  
Jorge Otero ◽  
Núria Farré ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Low Cost ◽  
Technical Information ◽  
Rabbit Aorta ◽  
Pressure Waveform ◽  
Mechanical Stimuli ◽  
Experimental Setting ◽  
Endothelial Response ◽  
Flow Through ◽  
Open Source Hardware

This paper describes the design, construction and testing of an experimental setting, making it possible to study the endothelium under different pathophysiological conditions. This novel experimental approach allows the application of the following stimuli to an ex vivo vessel in a physiological bath: (a) a realistic intravascular pressure waveform defined by the user; (b) shear stress in the endothelial layer since, in addition to the pressure waveform, the flow through the vessel can be independently controlled by the user; (c) conditions of hypo/hyperoxia and hypo/hypercapnia in an intravascular circulating medium. These stimuli can be applied alone or in different combinations to study possible synergistic or antagonistic effects. The setting performance is illustrated by a proof of concept in an ex vivo rabbit aorta. The experimental setting is easy to build by using very low-cost materials widely available. Online Supplement files provide all the technical information (e.g., circuits, codes, 3D printer drivers) following an open-source hardware approach for free replication.

scholarly journals Realization of frequency hopping characteristics of an epsilon negative metamaterial with high effective medium ratio for multiband microwave applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Tariqul Islam ◽  
Md. Moniruzzaman ◽  
Touhidul Alam ◽  
Md Samsuzzaman ◽  
Qutaiba A. Razouqi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Low Cost ◽  
Frequency Hopping ◽  
Small Dimension ◽  
Effective Medium ◽  
Unit Cell ◽  
Negative Permittivity ◽  
Design System ◽  
Microwave Applications ◽  
Meander Line

AbstractIn this paper, a meander-lines-based epsilon negative (ENG) metamaterial (MTM) with a high effective medium ratio (EMR) and near-zero refractive index (NZI) is designed and investigated for multiband microwave applications. The metamaterial unit cell is a modification of the conventional square split-ring resonator in which the meander line concept is utilized. The meander line helps to increase the electrical length of the rings and provides strong multiple resonances within a small dimension. The unit cell of proposed MTM is initiated on a low-cost FR4 substrate of 1.5 mm thick and electrical dimension of 0.06λ × 0.06λ, where wavelength, λ is calculated at the lowest resonance frequency (2.48 GHz). The MTM provides four major resonances of transmission coefficient (S21) at 2.48, 4.28, 9.36, and 13.7 GHz covering S, C, X, and Ku bands. It shows negative permittivity, near-zero permeability, and near-zero refractive index in the vicinity of these resonances. The equivalent circuit is designed and modeled in Advanced Design System (ADS) software. The simulated S21 of the MTM unit cell is compared with the measured one and both show close similarity. The array performance of the MTM is also evaluated by using 2 × 2, 4 × 4, and 8 × 8 arrays that show close resemblance with the unit cell. The MTM offers a high effective medium ratio (EMR) of 15.1, indicating the design's compactness. The frequency hopping characteristics of the proposed MTM is investigated by open and short-circuited the three outer rings split gaps by using three switches. Eight different combinations of the switching states provide eight different sets of multiband resonances within 2–18 GHz; those give the flexibility of using the proposed MTM operating in various frequency bands. For its small dimension, NZI, high EMR, and frequency hopping characteristics through switching, this metamaterial can be utilized for multiband microwave applications, especially to enhance the gain of multiband antennas.

scholarly journals Visualization of Surface Acoustic Waves in Thin Liquid Films

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
R. W. Rambach ◽  
J. Taiber ◽  
C. M. L. Scheck ◽  
C. Meyer ◽  
J. Reboud ◽  
...  
Keyword(s):  
Liquid Film ◽  
Acoustic Waves ◽  
Low Cost ◽  
Thin Liquid Film ◽  
Surface Acoustic Waves ◽  
Liquid Films ◽  
Theoretical Description ◽  
Propagation Path ◽  
Microfluidic Channels ◽  
Potential Applications

Abstract We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.

scholarly journals Recent Findings in Azaphilone Pigments

2021 ◽  
Vol 7 (7) ◽  
pp. 541
Author(s):  
Lúcia P. S. Pimenta ◽  
Dhionne C. Gomes ◽  
Patrícia G. Cardoso ◽  
Jacqueline A. Takahashi
Keyword(s):  
Water Solubility ◽  
Biological Activities ◽  
Low Cost ◽  
Scale Up ◽  
Structural Diversity ◽  
Downstream Processing ◽  
Global Market ◽  
Yield Improvement ◽  
Potential Applications ◽  
New Compounds

Filamentous fungi are known to biosynthesize an extraordinary range of azaphilones pigments with structural diversity and advantages over vegetal-derived colored natural products such agile and simple cultivation in the lab, acceptance of low-cost substrates, speed yield improvement, and ease of downstream processing. Modern genetic engineering allows industrial production, providing pigments with higher thermostability, water-solubility, and promising bioactivities combined with ecological functions. This review, covering the literature from 2020 onwards, focuses on the state-of-the-art of azaphilone dyes, the global market scenario, new compounds isolated in the period with respective biological activities, and biosynthetic pathways. Furthermore, we discussed the innovations of azaphilone cultivation and extraction techniques, as well as in yield improvement and scale-up. Potential applications in the food, cosmetic, pharmaceutical, and textile industries were also explored.

scholarly journals ResUHUrge: A Low Cost and Fully Functional Ventilator Indicated for Application in COVID-19 Patients

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6774
Author(s):  
Francisco José Vivas Fernández ◽  
José Sánchez Segovia ◽  
Ismael Martel Bravo ◽  
Carlos García Ramos ◽  
Daniel Ruiz Castilla ◽  
...  
Keyword(s):  
Low Cost ◽  
Pulmonary Ventilation ◽  
Lung Infection ◽  
Health Condition ◽  
Multidisciplinary Research ◽  
Global North ◽  
Severity Of The Disease ◽  
Open Source Hardware ◽  
The University

Although the cure for the SARS-CoV-2 virus (COVID-19) will come in the form of pharmaceutical solutions and/or a vaccine, one of the only ways to face it at present is to guarantee the best quality of health for patients, so that they can overcome the disease on their own. Therefore, and considering that COVID-19 generally causes damage to the respiratory system (in the form of lung infection), it is essential to ensure the best pulmonary ventilation for the patient. However, depending on the severity of the disease and the health condition of the patient, the situation can become critical when the patient has respiratory distress or becomes unable to breathe on his/her own. In that case, the ventilator becomes the lifeline of the patient. This device must keep patients stable until, on their own or with the help of medications, they manage to overcome the lung infection. However, with thousands or hundreds of thousands of infected patients, no country has enough ventilators. If this situation has become critical in the Global North, it has turned disastrous in developing countries, where ventilators are even more scarce. This article shows the race against time of a multidisciplinary research team at the University of Huelva, UHU, southwest of Spain, to develop an inexpensive, multifunctional, and easy-to-manufacture ventilator, which has been named ResUHUrge. The device meets all medical requirements and is developed with open-source hardware and software.

scholarly journals Color-Variable Photodynamic Antimicrobial Wool/Acrylic Blended Fabrics

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4141
Author(s):  
Tingting Wang ◽  
Wangbingfei Chen ◽  
Tingting Dong ◽  
Zihao Lv ◽  
Siming Zheng ◽  
...  
Keyword(s):  
Low Cost ◽  
Pathogen Transmission ◽  
Cationic Dyes ◽  
Light Illumination ◽  
Antibacterial Studies ◽  
Wool Fibers ◽  
Visible Light Illumination ◽  
Potential Applications ◽  
Dyed Fabrics ◽  
Acrylic Fibers

Towards the goal of developing scalable, economical and effective antimicrobial textiles to reduce infection transmission, here we prepared color-variable photodynamic materials comprised of photosensitizer (PS)-loaded wool/acrylic (W/A) blends. Wool fibers in the W/A blended fabrics were loaded with the photosensitizer rose bengal (RB), and the acrylic fibers were dyed with a variety of traditional cationic dyes (cationic yellow, cationic blue and cationic red) to broaden their color range. Investigations on the colorimetric and photodynamic properties of a series of these materials were implemented through CIELab evaluation, as well as photooxidation and antibacterial studies. Generally, the photodynamic efficacy of these dual-dyed fabrics was impacted by both the choice, and how much of the traditional cationic dye was employed in the dyeing of the W/A fabrics. When compared with the PS-only singly-dyed material, RB-W/A, that showed a 99.97% (3.5 log units; p = 0.02) reduction of Staphylococcus aureus under visible light illumination (λ ≥ 420 nm, 60 min), the addition of cationic dyes led to a slight decrease in the photoinactivation ability of the dual-dyed fabrics, but was still able to achieve a 99.3% inactivation of S. aureus. Overall, our findings demonstrate the feasibility and potential applications of low cost and color variable RB-loaded W/A blended fabrics as effective self-disinfecting textiles against pathogen transmission.

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