scholarly journals What is the optimal light source for optical mapping using voltage- and calcium-sensitive dyes?

2020 ◽  
pp. 599-607
Author(s):  
V Olejnickova ◽  
D Sedmera
Keyword(s):  
Light Source ◽  
Optical System ◽  
High Speed ◽  
Optical Mapping ◽  
The Other ◽  
Mouse Heart ◽  
Xenon Lamp ◽  
Light Sources ◽  
High Speed Imaging ◽  
Advantages And Disadvantages

Optical mapping is a fluorescence-based physiological method to image spreading of action potential in excitable tissues, such as the heart and central nervous system. Because of the requirements for high speed imaging in low light conditions, highly sensitive high-speed cameras together with an optical system with maximum photon efficiency are required. While the optimization of these two components is relatively straightforward, the choice of the perfect light source is less simple; depending on the other (usually fixed) components, various parameters may acquire different weight in decision-making process. Here we describe the rationale for building an optical mapping setup and consider the relative advantages and disadvantages of three different commonly available light sources: mercury vapor lamp (HBO), xenon lamp (XBO), and light emitting diode (LED). Using the same optical system (fluorescence macroscope) and high-speed camera (Ultima L), we have tested each of the sources for its ability to provide bright and even illumination of the field of view and measured its temporal fluctuations in intensity. Then we used each in the actual optical mapping experiment using isolated, perfused adult mouse heart or chick embryonic heart to determine the actual signal to noise ratio at various acquisition rates. While the LED sources have undergone significant improvements in the recent past, the other alternatives may still surpass them in some parameters, so they may not be the automatic number one choice for every application.

scholarly journals Open-Source Low-Cost Cardiac Optical Mapping System

2021 ◽  
Author(s):  
Dmitry Rybashlykov ◽  
Jaclyn Brennan ◽  
Zexu Lin ◽  
Igor R. Efimov ◽  
Roman Syunyaev
Keyword(s):  
Action Potential ◽  
Open Source ◽  
High Speed ◽  
Optical Mapping ◽  
Signal To Noise Ratio ◽  
Fluorescent Imaging ◽  
Source Image ◽  
Mouse Heart ◽  
Signal To Noise ◽  
Noise Ratio

Fluorescent imaging with voltage- or calcium-sensitive dyes, i.e. optical mapping, is one of the indispensable modern techniques to study cardiac electrophysiology, unsurpassed by temporal and spatial resolution. High-speed CMOS cameras capable of optical registration of action potential propagation are in general very costly. We present a complete solution priced below US$1,000 (including camera and lens) at the moment of publication with an open-source image acquisition and processing software. We demonstrate that the iDS UI-3130CP rev.2 camera we used in this study is capable of 200x200 977 frames per second (FPS) action potential recordings from rodent hearts. The signal-to-noise-ratio of a conditioned signal was 16 ± 10 for rodent hearts. A comparison with a specialized MiCAM Ultimate-L camera has shown that signal-to-noise ratio (SNR) is sufficient for accurate measurements of AP waveform, conduction velocity (± 0.04 m/s) and action potential duration (± 7ms) in mouse and rat hearts. We measured the action potential prolongation during 4-aminopyridine administration in mouse heart, showing that proposed system signal quality is adequate for drug studies.

Design of off-axis optical system applied for digital high-speed imaging

2015 ◽  
Vol 36 (2) ◽  
pp. 194-198
Author(s):  
Xie Hongbo ◽  
◽  
Zhu Shimin ◽  
Gong Yanxia ◽  
Xu Mengmeng
Keyword(s):  
Optical System ◽  
High Speed ◽  
High Speed Imaging

Spectral characteristics of road surfaces and eye transmittance: Effects on energy efficiency of road lighting at mesopic levels

2017 ◽  
Vol 50 (6) ◽  
pp. 842-861 ◽  
Author(s):  
OU Preciado ◽  
ER Manzano
Keyword(s):  
Energy Efficiency ◽  
Light Source ◽  
Spectral Characteristics ◽  
The Other ◽  
Visual Performance ◽  
Light Sources ◽  
Surface Reflectance ◽  
Road Lighting ◽  
Road Surfaces ◽  
Final Effect

In 2010, the CIE published a recommended system for mesopic photometry based on visual performance. According to this system, scenes illuminated at mesopic levels with light sources of high S/P ratio, will produce better visual performance than those illuminated with light sources of a lower S/P ratio at equal photopic luminance. However, there could be other factors affected by SPD that, when quantified, could lead to a contradictory final effect. The scope of this paper was to evaluate how road lighting is affected by the spectral road surface reflectance and by the human eye transmittance as people get older. Our results suggest that the benefits of considering the mesopic vision effect for light sources with high S/P ratios are totally counteracted by the other two effects at mesopic luminances between 0.75 cd/m2 and 1.73 cd/m2 for people between 20 and 60 years of age, depending on the light source and the age of observers.

scholarly journals High-throughput spatial sensitive quantitative phase microscopy using low spatial and high temporal coherent illumination

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azeem Ahmad ◽  
Vishesh Dubey ◽  
Nikhil Jayakumar ◽  
Anowarul Habib ◽  
Ankit Butola ◽  
...  
Keyword(s):  
Light Source ◽  
High Throughput ◽  
High Speed ◽  
Light Sources ◽  
Single Shot ◽  
Phase Sensitivity ◽  
Quantitative Phase ◽  
Phase Microscopy ◽  
Spatial Phase ◽  
Quantitative Phase Microscopy

AbstractHigh space-bandwidth product with high spatial phase sensitivity is indispensable for a single-shot quantitative phase microscopy (QPM) system. It opens avenue for widespread applications of QPM in the field of biomedical imaging. Temporally low coherence light sources are implemented to achieve high spatial phase sensitivity in QPM at the cost of either reduced temporal resolution or smaller field of view (FOV). In addition, such light sources have low photon degeneracy. On the contrary, high temporal coherence light sources like lasers are capable of exploiting the full FOV of the QPM systems at the expense of less spatial phase sensitivity. In the present work, we demonstrated that use of narrowband partially spatially coherent light source also called pseudo-thermal light source (PTLS) in QPM overcomes the limitations of conventional light sources. The performance of PTLS is compared with conventional light sources in terms of space bandwidth product, phase sensitivity and optical imaging quality. The capabilities of PTLS are demonstrated on both amplitude (USAF resolution chart) and phase (thin optical waveguide, height ~ 8 nm) objects. The spatial phase sensitivity of QPM using PTLS is measured to be equivalent to that for white light source and supports the FOV (18 times more) equivalent to that of laser light source. The high-speed capabilities of PTLS based QPM is demonstrated by imaging live sperm cells that is limited by the camera speed and large FOV is demonstrated by imaging histopathology human placenta tissue samples. Minimal invasive, high-throughput, spatially sensitive and single-shot QPM based on PTLS will enable wider penetration of QPM in life sciences and clinical applications.

scholarly journals The dynamics of centromere motion through the metaphase-to-anaphase transition reveal a centromere separation order

2019 ◽  
Author(s):  
Jonathan W. Armond ◽  
Katie L. Dale ◽  
Nigel J. Burroughs ◽  
Andrew D. McAinsh ◽  
Elina Vladimirou
Keyword(s):  
Chromosome Segregation ◽  
High Speed ◽  
Daughter Cell ◽  
Mitotic Chromosome ◽  
Low Frequency ◽  
The Other ◽  
Bayesian Modelling ◽  
High Speed Imaging ◽  
Chromosome Dynamics ◽  
Sister Chromatids

AbstractDuring cell division, chromosomes align at the equator of the cell before sister chromatids separate to move to each daughter cell during anaphase. We use high-speed imaging, Bayesian modelling and quantitative analysis to examine the regulation of centromere dynamics through the metaphase-to-anaphase transition. We find that, contrary to the apparent instantaneous separation seen in low-frequency imaging, centromeres separate asynchronously over 1-2 minutes. The timing of separations negatively correlates with the centromere intersister distance during metaphase, which could potentially be explained by variable amounts of cohesion at centromeres. Depletion of condensin I increases this asynchrony. Depletion of condensin II, on the other hand, abolishes centromere metaphase oscillations and impairs centromere speed in anaphase. These results suggest that condensin complexes have broader direct roles in mitotic chromosome dynamics than previously believed and may be crucial for the regulation of chromosome segregation.

A new continuous light source for high-speed imaging

2017 ◽  
Author(s):  
R. T. Paton ◽  
R. E. Hall ◽  
B. W. Skews
Keyword(s):  
Light Source ◽  
High Speed ◽  
Continuous Light ◽  
High Speed Imaging

Developments in Apparatus and Techniques for Time-Resolved Spectroscopy

1967 ◽  
Vol 21 (2) ◽  
pp. 100-113 ◽  
Author(s):  
Á. Bardócz
Keyword(s):  
Light Source ◽  
High Precision ◽  
Optical System ◽  
Time Resolution ◽  
Physical Meaning ◽  
Low Voltage ◽  
Signal Generator ◽  
Light Sources ◽  
Time Resolved ◽  
Magnetic Coil

Spectra dispersed only according to wavelength have a limited physical meaning since they fail to reveal the changes in the light source in time. Electronically controlled spectroscopic light sources operating with high precision in time make possible the production of time-resolved spectra, which can be represented as a function of wavelength and time. Resolution in time is accomplished with the aid of rotating mirrors and disks, fitted in the optical system of conventional spectrographs. The time-revolving element and the light source are synchronized magnetically or by means of a photocell. The light source is controlled by a trigger signal generator driven by a photocell or a magnetic coil. The rotating mirror or disk, driven by a synchronous motor from the mains voltage, is incorporated in a mechanical apparatus, making possible electric phase adjustments. Several details of time-resolved spectra of high- and low-voltage sparks and of ac arcs are demonstrated.

scholarly journals Internet based light quality measurement

2017 ◽  
Vol 4 (1.) ◽  
Author(s):  
Krisztián Samu ◽  
Bálint Thamó
Keyword(s):  
Everyday Life ◽  
Light Source ◽  
Light Quality ◽  
Quality Measurement ◽  
Basic Theory ◽  
Human Interaction ◽  
The Other ◽  
Color Temperature ◽  
Light Sources ◽  
Calculation Methods

The goal of this project was to implement a device, which can measure the illuminance and the correlated color temperature (CCT) of a light source and also works as a webserver. The analyzation of light sources is very important in our everyday life. With the use of a webserver the measured values are easily accessible and the calculation methods can be changed without any changes on the hardware. It also provides a solution to store and analyze the results without further human interaction. Therefore the device is capable of collecting and analyzing a large amount of data. For these criterions we chose a PIC microcontroller, an Ethernet chip and two different sensors. One of the sensors is an RGB sensor and the other one is a LUX sensor. Both of the sensors are using photodiodes to sense the different attributions of a light source. Through this article we show the basic theory behind the project, the implementation and calibration of the device; then the results of the measurements and finally we mention some possibilities for future improvements.

Organic Light Emitting Diodes - Innovative Light Sources

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny
Keyword(s):  
Light Source ◽  
Organic Light Emitting Diodes ◽  
Organic Leds ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Lighting Systems ◽  
Physical Principles ◽  
Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

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