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Fluorescent Technology in the Assessment of Metabolic Disorders in Diabetes
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Elena V. Zharkikh, Viktor V. Dremin, Andrey V. Dunaev
The study included the skin fluorescence spectra recording upon excitation with 365- and 450-nm light, as well as recording the LDF signal under thermoneutral conditions and during a series of temperature tests with temperature modes of 25°C, 35°C, and 42°C, respectively. A multi-optical fiber probe was used for delivery of probing radiation and registration of back-reflected secondary radiation from the tissue. The probe was secured on the dorsal surface of the foot to a point located on a plateau between the 1st and 2nd metatarsal bones. Figure 9.6 shows the location of the optical sensor on the patient’s foot. To register these parameters, the “LAZMA-D” (SPE “LAZMA” Ltd, Russia) system was used, which consists of a “LAZMA-MC” multichannel laser analyzer and a “LAZMA-TEST” unit for providing functional tests.
Rapid Methods in Cosmetic Microbiology
Published in Philip A. Geis, Cosmetic Microbiology, 2020
The Biolumix and Soleris Neogen systems employ a variety of broth media that will encourage the growth of target microorganisms. The vials contain unique dyes in which microbial growth is detected by changes in color or fluorescence. An optical sensor detects these changes, which are expressed as light intensity units. The vials are also constructed with two independent zones: an upper incubation zone and a lower reading zone. The two zones eliminate masking of the optical pathway by the test sample and/or by microbial turbidity.
Presentation Format
Published in Kitsakorn Locharoenrat, Research Methodologies for Beginners, 2017
Sensor Module. Optical sensor is LDR (light-dependent resistor) served as a light detector with the aperture angle of 60°. As we detect the sun position with three sensors for one direction, this allows us to increase the exposure of the sun up to 180°. The LDR is designed according to a principle of shadow from the aluminum bar as shown in Fig. 1(a). For altitude-LDR as shown in Fig. 1(b), when the sun’s rays are parallel with the aluminum bar in altitude line, three sensors at the upper position represented by T1T2T3 and another three sensors at the lower position represented by T4T5T6 can detect the maximum light intensity. Our tracking program is set at “ON” whereas a logic state is set to be“1”. For azimuth-LDR as shown in Fig. 1(b), three sensors at the left position represented by Z1Z2Z3 and another three sensors at the right position represented by Z4Z2Z6 cannot detect the light. Our tracking program is set at “OFF” position whereas a logic state is set to be “0”. By contrast, if the sun’s rays are parallel with the aluminum bar in azimuth line, the altitude-LDR will show “OFF” and “0”, whilst the azimuth-LDR will show “ON” and “1”.
Evaluation of salivary melatonin concentrations as a circadian phase maker of morning awakening and their association with depressive mood in postpartum mothers
Published in Chronobiology International, 2021
Naoko Kudo, Hitomi Shinohara, Satoko Kagabu, Hideya Kodama
On the day of recruitment, we explained how to use a wristwatch-type acceleration sensor equipped with an optical sensor (Watchware actigraph, Ambulatory Monitoring Inc., Ardsley, NY, USA). Next, each mother took the actigraphy watch home, put it on her nondominant wrist about 1 h before bedtime, and kept wearing it until the morning 3 d later, except when taking a bath. To monitor ambient light exposure as accurately as possible during sleep, we asked mothers to try and keep the hand with the wristwatch exposed (not under a blanket) while they slept. While wearing the wristwatch, the mothers recorded the time they went to bed, their estimated sleep onset time, their awakening periods during nocturnal sleep, and their estimated sleep offset time for every 3 d in a diary. The mothers then mailed watches that had been worn for 3 d to our laboratory. The activity and light data were downloaded from the watch using ACTme software (ver. 3.10.0.3; Ambulatory Monitoring Inc.).
Molecular Diagnostic Tools for the Detection of SARS-CoV-2
Published in International Reviews of Immunology, 2021
Manali Datta, Desh Deepak Singh, Afsar R. Naqvi
Optical biosensors utilize light to monitor interaction (binding or a reaction) between a probe and an analyte by determining changes in light absorption post-interaction. Label-free optical sensor may percept the change in refractive index and thus confirm binding of the analyte–probe molecule. Alternatively, optical sensors can utilize fluorescent tags that have the capability to produce or quench a signal upon interaction between analyte and probe. Gravimetric biosensors use the basic principle of a response to detect change in mass due to binding between probe and analyte. Acoustic-based gravimetric sensors perceive the alteration in resonating frequency corresponding to the binding of the analyte and probe and thus the increase in mass of the bimolecular complex. Electrochemical sensors detect the change in electron flow between interacting molecules and represent it as resultant change in electric current [41]. An interaction between two biological macromolecules often results in the flux of electrons. Leveraging electron level changes may reveal molecular interactions, which thereafter may be assessed quantitatively or semi-quantitatively. Various interacting partners like DNA–DNA, DNA–RNA, DNA–protein, and protein–ligand have been envisaged for designing electrochemical biosensors as in vitro diagnostics.
The intensity of oscillations of the photoplethysmographic waveform variability at frequencies 0.04–0.4 Hz is effective marker of hypertension and coronary artery disease in males
Published in Blood Pressure, 2020
Anton R. Kiselev, Anatoly S. Karavaev
One of the problems we encountered using photoplethysmogram is the difficulty of interpreting the absolute values of photoplethysmogram waveforms. The output signal of the photoplethysmographic optical sensor is proportional to an unknown coefficient, which depends on a number of factors such as the optical characteristics of a subject’s skin, blood pressure values, sensor placement, sensor’s electrical and optical characteristics, and illumination and temperature in the room. Photoplethysmographic waveform absolute values were measured in conventional units (cu), which were defined as a proportion of a discrete sample of photoplethysmogram waveform to the signal at the optical sensor output. Since the coefficient of proportionality between the volume blood flow and cu is unknown, the interpretation of absolute values of low-frequency, high-frequency, and total powers of the photoplethysmographic spectrum is difficult. We do not use these spectral indices in this paper. However, the dimensionless measurements LF/HF, LF%, and HF% are applicable.