Journal articles: 'Biomedical photometer'

1

Bezuglaya, N. V., A. A. Haponiuk, D. V. Bondariev, S. A. Poluectov, V. A. Chornyi, and M. A. Bezuglyi. "Rationale for the Choice of the Ellipsoidal Reflector Parameters for Biomedical Photometers." Devices and Methods of Measurements 12, no. 4 (December 22, 2021): 259–71. http://dx.doi.org/10.21122/2220-9506-2021-12-4-259-271.

Full text

Abstract:

Biomedical photometersʼ information-measuring systems with ellipsoidal reflectors have acceptable results in determining of biological tissues optical properties in the visible and near-infrared spectral range. These photometers make it possible to study the optical radiation propagation in turbid media for direct and inverse problems of light-scattering optics. The purpose of this work is to study the influence of the ellipsoidal reflectors design parameters on the results of biomedical photometry when simulating the optical radiation propagation in a system of biological tissue and reflectors in transmitted and reflected light.The paper substantiates the choice of the ellipsoidal reflectors’ focal parameter for efficient registration of forward and backscattered light. The methodology of the process is illustrated by the results of a model experiment using the Monte Carlo simulation for samples of human brain white and gray matter at the visible range of 405 nm, 532 nm, and 650 nm. The total transmittance, diffuse reflectance, and absorption graphs depending on the sample thickness were obtained. Based on the introduced concepts of the ellipsoidal reflector efficiency index and its efficiency factor, the expediency of choosing the ellipsoidal reflectors focal parameter is analyzed to ensure the registration of the maximum amount of scattered light. The graphs of efficiency index in reflected and transmitted light for different thickness samples of white and gray matter and efficiency factors depending on the sample thickness were obtained.The influence of the reflectors ellipticity on the illuminance of various zones of photometric images using the example of an absorbing biological medium – pig liver tissue – at wavelength of 405 nm with a Monte Carlo simulation was analyzed.The optical properties of biological media (scattering and absorption coefficients, scattering anisotropy factor, refractive index) and the samples’ geometric dimensions, particularly the thickness, are predetermined when choosing the ellipsoidal reflectors parameters for registration of the scattered light. Coordinates of the output of photons and their statistical weight obtained in the Monte Carlo simulation of light propagation in biological tissue have a physical effect on a characteristic scattering spot formation in the receiving plane of a biomedical photometer with ellipsoidal reflectors.

APA, Harvard, Vancouver, ISO, and other styles

2

Bezugla, Natalia, Serhii Poluectov, Vladyslav Chornyi, and Mikhail Bezuglyi. "MONTE CARLO SIMULATION OF LIGHT SCATTERING IN HUMAN SKIN LAYERS BY SPATIAL PHOTOMETRY METHODS." Bulletin of Kyiv Polytechnic Institute. Series Instrument Making, no. 61(1) (June 30, 2021): 91–100. http://dx.doi.org/10.20535/1970.61(1).2021.237112.

Full text

Abstract:

The ability to register and analyze the spatial distribution of light scattered within the full solid angle is the basis for the development and improvement of information-measuring systems and software and hardware complexes for problems of optical biomedical diagnostics. The greatest contribution to light scattering at non-invasive methods of biomedical research are made by the layers of human skin, affecting the depth of probing and the resolution of diagnostic systems. The significant individual variability of the optical properties of biological tissues does not allow practically (clinically) assessing their effect on the light scattering characteristics; therefore, the use of methods for modeling the optical radiation propagation in media in the measuring tools functioning context makes it possible to provide such a prognostic analysis. The goal of this work is a comparative evaluation of the results of the light propagation in human skin layers by Monte Carlo simulation using information-measuring systems of a biomedical photometer with ellipsoidal reflectors and a goniophotometer. The Monte Carlo simulation results of light scattering in dermis and epidermis at a wavelength of 632.8 nm using spatial photometry methods and the "BT_Mod" software, as well as coordinates, direction, and statistical weight of photons, allows the ray-tracing in a biomedical photometer with ellipsoidal reflectors are presented in this work. As a result of modeling, graphs of the dependence of optical coefficients (transmission T, diffuse reflection Rd, and absorption A) for the studied tissues of various thicknesses on the value of the scattering anisotropy factor were obtained, as well as photometric images of the second focal plane of ellipsoidal reflectors when receiving a scattering spot in reflected and transmitted light. Diagrams of the averaged scattering indicatrix at three thicknesses of the epidermis and dermis were obtained for a set of biophysically significant values of the scattering anisotropy factor, based on which the integral distribution of the photons statistical weight in diffuse scattered light was analyzed. A quantitative assessment of the illuminance level of images is carried out according to the zone analysis principles in photometry by ellipsoidal reflectors. The resulting graphs of the illuminance dependence the external and middle rings of photometric images in reflected and transmitted light. The results of the research make it possible to analyze the spatial distribution of light scattered by the human skin layers (epidermis and dermis) within the full solid angle, which can be used in problems of optical dosimetry and medical imaging in diagnostic, endoscopic, and therapeutic methods of biophotonics.

APA, Harvard, Vancouver, ISO, and other styles

3

Bezuglyi, M. A., N. V. Bezuglaya, and S. Kostuk. "INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS." Devices and Methods of Measurements 9, no. 1 (March 20, 2018): 56–65. http://dx.doi.org/10.21122/2220-9506-2018-9-1-56-65.

Full text

Abstract:

The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue) of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer) the influence of profile can be observed only for derma in reflected layer and is equal not more than 15 %.

APA, Harvard, Vancouver, ISO, and other styles

4

Karlsson, Jan Olof G., Nils Grundstrom, Hans Elwing, and Rolf G. G. Andersson. "The Fish Pigment Cell: An Alternative Model in Biomedical Research." Alternatives to Laboratory Animals 18, no. 1_part_1 (November 1990): 201–24. http://dx.doi.org/10.1177/026119299001800121.1.

Full text

Abstract:

Receptor-mediated pigment aggregation within pigment cells (chromatophores) of an isolated fish scale is an ideal model system for functional receptor studies. The superficial layer of the scale contains both dermal chromatophores and postganglionic sympathetic nerves. By means of stimulation of the nerves, or by addition of appropriate receptor agonists, it is possible to elicit pigment aggregation within the chromatophores. A single fish can contribute hundreds of scales, various pharmacological and biochemical experiments are easily carried out and the physiological response, i.e. pigment aggregation, is readily evaluated by the aid of a light microscope or a simple scale photometer. A denervation model, based on isolated scales, permits studies of factors involved in the sensitivity change, which typically takes place after experimental or pathological denervation. By using isolated fish scales it is quite simple to illustrate many biomedically important concepts, like receptor theory and nerve-effector cell communication. This makes the scale a very useful preparation in biomedical education.

APA, Harvard, Vancouver, ISO, and other styles

5

Goode, D. H., and R. C. Pointon. "Calibration of the Nuclear Associates 07-621 precision photometer." Australasian Physics & Engineering Sciences in Medicine 28, no. 2 (June 2005): 111–14. http://dx.doi.org/10.1007/bf03178701.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Shiffers, L. A., P. I. Bresler, and Ya S. Polyakov. "Means of checking an automatic two-dimensional photometer for immunological research." Biomedical Engineering 25, no. 3 (May 1991): 145–47. http://dx.doi.org/10.1007/bf00566715.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Камзин, А. С., H. Das, N. Wakiya, and А. А. Валиуллин. "Магнитные нанокомпозиты MgFe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=-/SiO-=SUB=-2-=/SUB=- типа ядро/оболочка для биомедицинских применений: синтез и свойства." Физика твердого тела 60, no. 9 (2018): 1707. http://dx.doi.org/10.21883/ftt.2018.09.46388.019.

Full text

Abstract:

AbstractMagnetic core/shell (CS) nanocomposites (MNCs) are synthesized using a simple method, in which a magnesium ferrite nanoparticle (MgFe_2O_4) is a core, and an amorphous silicon dioxide (silica SiO_2) layer is a shell. The composition, morphology, and structure of synthesized particles are studied using X-ray diffraction, field emission electron microscopy, transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), scattering electrophoretic photometer, thermogravimetric analysis (TGA), and Mössbauer spectroscopy. It is found that the MgFe_2O_4/SiO_2 MNC has the core/shell structure formed by the Fe‒O–Si chemical bond. After coating with silica, the MgFe_2O_4/SiO_2 MNC saturation magnetization significantly decreases in comparison with MgFe_2O_4 particles without a SiO_2 shell. Spherical particles agglomerated from MgFe_2O_4 nanocrystallites ∼9.6 and ∼11.5 nm in size function as cores coated with SiO_2 shells ∼30 and ∼50 nm thick, respectively. The total size of obtained CS MNCs is ∼200 and 300 nm, respectively. Synthesized CS MgFe_2O_4/SiO_2 MNCs are very promising for biomedical applications, due to the biological compatibility of silicon dioxide, its sizes, and the fact that the Curie temperature is in the region required for hyperthermal therapy, 320 K.

APA, Harvard, Vancouver, ISO, and other styles

8

Michalak, Gregory J., Heather A. Anderson, and D. Patrick O'Neal. "Feasibility of Using a Two-Wavelength Photometer to Estimate the Concentration of Circulating Near-Infrared Extinguishing Nanoparticles." Journal of Biomedical Nanotechnology 6, no. 1 (February 1, 2010): 73–81. http://dx.doi.org/10.1166/jbn.2010.1094.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Modibo Coulibaly, Jean Luis Konan, Mary Laure Hauhouot Attoungbre, and Dagui Monnet. "Electrolytes internal quality control by using ISO 15189 version 2007: Particular requirements for quality and competence for biomedical laboratories." World Journal of Advanced Research and Reviews 14, no. 1 (April 30, 2022): 293–301. http://dx.doi.org/10.30574/wjarr.2022.14.1.0321.

Full text

Abstract:

Background: the blood electrolytes analysis is a routine laboratory test which proper execution would help in the diagnosis of hydro-electrolytes disorders. The objective of this work was to assess the internal quality control of the sodium and potassium tests from the pre-pre-analytical phase to the post-analytical phase. Material and Methods: This was a cross-sectional study which took in the laboratory of biochemistry at the Institute of Cardiology, Abidjan, Ivory Coast from March 1st to March 31, 2009. We used the flame photometer to measure the sodium and potassium electrolytes level in the internal control Exatrol-Normal from Biolabo®. Clinical samples were also taken for the determination of the same electrolytes levels. The pre-pre-analytical quality indicators depending on the physicians order, the pre-analytical quality, the analytical quality and the post-analytical indicators under the control of the laboratory were assessed by using “NF en ISO 15189 version 2007” check list: Particular requirements for quality and competence for biomedical laboratories paragraph 5.4.1, 5.4.2, 5.5 and 5.7. Data were captured into Microsoft Excel [Microsoft Corporation, Redmond, WA] and then imported and analyzed using QI Macros SPC Software for Excel®. The levels of Na+ and K+ in the control material Exatrol Normal from Biolabo® were represented as follow: mean (m), Standard deviation (SD). The values of the monthly distribution of Na+ and K+ concentrations around the mean were used to draw the Levey-Jennings diagram and Wesgard’s rules were used to evaluate the performances of the analytical process. Results: a total of 112 electrolytes analysis order were received at the biochemistry laboratory. For the pre-pre-analytical phase, the analysis of these requests forms revealed that 81 (72.3%) requests forms carried no clinical information. The non-compliance of the samples were mainly represented by the sampling under tight tourniquet 4 (3.6%), followed by the non-respect of the succession of tubes during multiple sampling process 3 (2.7%). For the analytical phase, the monthly Levey-Jennings diagram showed a dispersion of the two electrolytes Exatrol-Normal Biolabo® levels between the mean plus or minus 2 standard deviations [m ± 2SD]: 139.34 ± 2.84 mmol/L for Na+ and for K+, between [m± SD]: 4.2 ± 0.78 mmol/L. The analytical performances assessment for the two Levey-Jennings diagrams by using Wesgard’s rules did not found any significant critical deviations with regard to the distribution of Na+ and K+ levels. For clinical samples, isolated hyponatremia was the most common disturbance (30.4%) followed by isolated hypokalemia (12.5%). At the post-analytical phase we observed for test execution a mean turnaround time of 34 ± 5.2 minutes with extremes ranging from 23 to 95 minutes. One case (0.9%) of transcription error was noted. Conclusion: the internal quality control process is applied in the clinical biochemistry laboratory at the Institute of Cardiology, Abidjan. A systematic verification system of the different phases of the analytical process helped to follow quality indicators at all levels of the pre, analytical and post analytical process and corrective actions were taken if necessary. Better collaboration between clinicians requesting electrolytes analysis and biologists performing the analysis is necessary to improve the pre-pre-analytical phase and, beyond that, improve the patient outcome throughout a comprehensive care.

APA, Harvard, Vancouver, ISO, and other styles

10

Bezuglyi, Mikhail, Olga Linyucheva, Natalia Bezuglaya, Mikhail Byk, and Stepan Kostiuk. "CONTROL OF THE ELLIPSOIDAL REFLECTORS SHAPE FOR BIOMEDICAL PHOTOMETERS." Bulletin of Kyiv Polytechnic Institute. Series Instrument Making, no. 53(1) (June 30, 2017): 62–69. http://dx.doi.org/10.20535/1970.53(1).2017.106543.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Imad, Abdulrahman, Noreha Abdul Malik, Belal Ahmed Hamida, Gan Hong Hong Seng, and Sheroz Khan. "Acoustic Photometry of Biomedical Parameters for Association with Diabetes and Covid-19." Emerging Science Journal 6 (February 7, 2022): 42–56. http://dx.doi.org/10.28991/esj-2022-sper-04.

Full text

Abstract:

Because of their mortality rate, diabetes and COVID-19 are serious diseases. Moreover, people with diabetes are at a higher risk of developing COVID-19 complications. This article therefore proposes a single, non-invasive system that can help people with diabetes and COVID-19 to monitor their health parameters by measuring oxygen saturation (SPO2), heart rate, and body temperature. This is in contrast to other pulse oximeters and previous work reported in the literature. A Max30102 sensor, consisting of two light-emitting diodes (LEDs), can serve as a transmission spectrum to enable three synchronous parameter measurements. Hence, the Max30102 sensor facilitates identification of the relationship between COVID-19 and diabetes in a cost-effective manner. Fifty subjects (20 healthy, 20 diabetic, and 10 with COVID-19), aged 18-61 years, were recruited to provide data on heart rate, body temperature, and oxygen saturation, measured in a variety of activities and scenarios. The results showed accuracy of ±97% for heart rate, ±98% for body temperature, and ±99% for oxygen saturation with an enhanced time efficiency of 5-7 seconds in contrast to a commercialized pulse oximeter, which took 10-12 seconds. The results were then compared with those of commercially available pulse oximetry (Oxitech Pulse Oximeter) and a thermometer (Medisana Infrared Thermometer). These results revealed that uncontrolled diabetes can be as dangerous as COVID-19 in terms of high resting heart rate and low oxygen saturation. Doi: 10.28991/esj-2022-SPER-04 Full Text: PDF

APA, Harvard, Vancouver, ISO, and other styles

12

Hamza, Alnazier Osman, Issam Osman Elhassan Elkhalifa, and Mohamed Omer Khider Hassan. "Appropriateness of Clinical Laboratory Photometers Quality Requirements." Journal of Clinical Engineering 37, no. 3 (2012): 102–8. http://dx.doi.org/10.1097/jce.0b013e31825ce841.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Tugal-Tutkun, Ilknur, F. Nilüfer Yalçındağ, and Carl P. Herbort. "Laser flare photometry and its use in uveitis." Expert Review of Ophthalmology 7, no. 5 (October 2012): 449–57. http://dx.doi.org/10.1586/eop.12.47.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Campora, Lorenzo Donato, Christoph Metzger, Stephan Dähnhardt-Pfeiffer, Roland Drexel, Florian Meier, and Siegfried Fürtauer. "Fluorescence Labeling of Cellulose Nanocrystals—A Facile and Green Synthesis Route." Polymers 14, no. 9 (April 29, 2022): 1820. http://dx.doi.org/10.3390/polym14091820.

Full text

Abstract:

Efficient chemical modification of cellulose nanocrystals (CNCs) by grafting commonly involves aprotic solvents, toxic reactants, harsh reaction conditions, or catalysts, which have negative effects on the particle character, reduced dispersibility and requires further purification, if products are intended for biomedical applications. This work, in contrast, presents a robust, facile, and green synthesis protocol for the grafting of an amino-reactive fluorophore like fluorescein isothiocyanate (FITC) on aqueous CNCs, combining and modifying existent approaches in a two-step procedure. Comparably high grafting yields were achieved, which were confirmed by thermogravimetry, FTIR, and photometry. The dispersive properties were confirmed by DLS, AF4-MALS, and TEM studies. The presented route is highly suitable for the introduction of silane-bound organic groups and offers a versatile platform for further modification routes of cellulose-based substrates.

APA, Harvard, Vancouver, ISO, and other styles

15

Gourmelin, Y., B. Gouget, and A. Truchaud. "Electrode measurement of glucose and urea in undiluted samples." Clinical Chemistry 36, no. 9 (September 1, 1990): 1646–49. http://dx.doi.org/10.1093/clinchem/36.9.1646.

Full text

Abstract:

Abstract The development of ion-selective electrodes (ISEs) for electrolyte measurements necessitates a re-evaluation of the biological and clinical interpretation of a result. In pathological situations (e.g., hyperlipidemia and hyperproteinemia) direct potentiometry is the method of choice for ion measurements in blood. However, the "plasma water effect" exists also in normal samples, requiring new reference values for physiological ranges. A compromise between medical and instrumentation workers retained the old reference values (flame photometry for Na+ and K+) by introducing correction factors into the ISE instruments, so that the results for direct ISE and flame photometry are the same for "normal" samples. Analyses of "abnormal" samples will reveal biases between the two methods. Now, a new generation of electrodes for assaying additional metabolites reopens the issue. Although classical methods measure a quantity of substance in a predetermined volume of sample, the majority of the substance is usually in the aqueous phase, and the volumes occupied by lipid and protein are not taken into consideration. In evaluating the NOVA 12 instrument (NOVA Biomedical), using electrodes for direct measurement in serum or plasma of Na, K, Cl, total CO2, urea, and glucose, we have demonstrated the inadequacy of classical measurements of urea and glucose, especially in pathological situations characterized by a large variation in the plasma water fraction.

APA, Harvard, Vancouver, ISO, and other styles

16

Sui, Kunyang, Marcello Meneghetti, Jaspreet Kaur, R. J. F. Sørensen, Rune W. Berg, and Christos Markos. "Adaptive polymer fiber neural device for drug delivery and enlarged illumination angle for neuromodulation." Journal of Neural Engineering 19, no. 1 (February 1, 2022): 016035. http://dx.doi.org/10.1088/1741-2552/ac5267.

Full text

Abstract:

Abstract Objective. Optical fiber devices constitute significant tools for the modulation and interrogation of neuronal circuitry in the mid and deep brain regions. The illuminated brain area during neuromodulation has a direct impact on the spatio-temporal properties of the brain activity and depends solely on the material and geometrical characteristics of the optical fibers. In the present work, we developed two different flexible polymer optical fibers (POFs) with integrated microfluidic channels (MFCs) and an ultra-high numerical aperture (UHNA) for enlarging the illumination angle to achieve efficient neuromodulation. Approach. Three distinct thermoplastic polymers: polysulfone, polycarbonate, and fluorinated ethylene propylene were used to fabricate two step-index UHNA POF neural devices using a scalable thermal drawing process. The POFs were characterized in terms of their illumination map as well as their fluid delivery capability in phantom and adult rat brain slices. Main results. A 100-fold reduced bending stiffness of the proposed fiber devices compared to their commercially available counterparts has been found. The integrated MFCs can controllably deliver dye (trypan blue) on-demand over a wide range of injection rates spanning from 10 nl min−1 to 1000 nl min−1. Compared with commercial silica fibers, the proposed UHNA POFs exhibited an increased illumination area by 17% and 21% under 470 and 650 nm wavelength, respectively. In addition, a fluorescent light recording experiment has been conducted to demonstrate the ability of our UHNA POFs to be used as optical waveguides in fiber photometry. Significance. Our results overcome the current technological limitations of fiber implants that have limited illumination area and we suggest that soft neural fiber devices can be developed using different custom designs for illumination, collection, and photometry applications. We anticipate our work to pave the way towards the development of next-generation functional optical fibers for neuroscience.

APA, Harvard, Vancouver, ISO, and other styles

17

SANKAI, Y., T. TSUTSUI, T. JIKUYA, O. SHIGETA, M. OHTA, and T. MITSUI. "Method of Noninvasive and Continuous Hemolysis/Thrombogenesis Measurement by Laser Photometry During Artificial Heart Development." ASAIO Journal 43, no. 5 (September 1997): M686. http://dx.doi.org/10.1097/00002480-199709000-00071.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Eickner, Thomas, Michael Teske, Natalia Rekowska, Volkmar Senz, Klaus-Peter Schmitz, and Niels Grabow. "A hydrogel based quasi-stationary test system for in vitro dexamethasone release studies for middle ear drug delivery systems." Current Directions in Biomedical Engineering 7, no. 2 (October 1, 2021): 692–95. http://dx.doi.org/10.1515/cdbme-2021-2176.

Full text

Abstract:

Abstract For the investigation of in vitro drug release, methods have been used in which samples of drug delivery systems are immersed in release medium. The medium is used to measure drug concentration via chromatography or photometry. These systems are suitable to investigate the drug release of different systems or to simulate tissue environments. When considering predominantly humid regions, e.g. for drug release into the cochlea through the round window membrane by a drug delivery system placed at that membrane, reproducible in vitro determination of drug release becomes particularly challenging. In this study the development of a system is reported that allows the investigation of the in vitro drug release simulating such conditions. The presented test system consists of an alginate hydrogel in glass vials simulating the biological membrane, which separates the drug delivery system from the medium filled compartment. Saline is used as release medium and injected under the hydrogel. The samples are placed on top of the hydrogel, which slightly contacts the medium surface. The drug concentration in the release medium was determined by HPLC measurements. This system allows for testing the release of dexamethasone without the samples being completely surrounded by medium. The hydrogel mediates the diffusion of the drug by ensuring the contact with the medium. Release was monitored for more than 23 days. The presented concept was successfully designed and manufactured. The system is inexpensive and can be duplicated easily. In this study, it was used to monitor the drug release of dexamethasone from PEGDA700 derived polymer. One challenge that remains to be considered is the low mechanical stability of the hydrogel, which results in a need for repeated manufacturing during the handling of the system.

APA, Harvard, Vancouver, ISO, and other styles

19

Kopyakov, L. N., O. B. Kostrova, V. E. Kurochkin, L. K. Panina, and D. Yu Uglov. "Recording of the results of the indirect hemagglutination test in the microanalysis class by vertical photometry." Biomedical Engineering 20, no. 5 (September 1986): 152–55. http://dx.doi.org/10.1007/bf00563380.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Thomaneck, U., J. Vienken, U. Waldschläger, M. Diamantoglou, W. Schütt, D. Falkenhagen, and H. Klinkmann. "Detection of Charges and their Distribution on Dialysis Membranes with Cationic/Anionic Dyes Using Confocal Laser Scanning Microscopy." International Journal of Artificial Organs 14, no. 11 (November 1991): 686–90. http://dx.doi.org/10.1177/039139889101401102.

Full text

Abstract:

Methods for the detection of positive or negative charges on the surface of biomaterials/membranes and inside a membrane are important for the characterisation of such materials. We tested different dyes and optimized staining procedures. Under standardized conditions negatively charged membranes were stained with cationic triarylmethane compounds such as crystal violet and positively charged membranes with the anionic anthraquinone dye anthralan blue B. There was no staining of uncharged cellulose membranes. The applicability of these methods was demonstrated on membranes coated to varying degrees with charged compounds such as heparin, these changes in charge being detectible quantitatively by photometry. The distribution of charges inside a membrane was detected by optical sectioning across the stained (FITC labelled poly-L-lysine) membrane using confocal laser scanning microscopy (LSM). LSM offers a completely new application possibility in biomaterial and biocompatibility research.

APA, Harvard, Vancouver, ISO, and other styles

21

Chattopadhyay, Ishanu, and Hod Lipson. "Data smashing: uncovering lurking order in data." Journal of The Royal Society Interface 11, no. 101 (December 6, 2014): 20140826. http://dx.doi.org/10.1098/rsif.2014.0826.

Full text

Abstract:

From automatic speech recognition to discovering unusual stars, underlying almost all automated discovery tasks is the ability to compare and contrast data streams with each other, to identify connections and spot outliers. Despite the prevalence of data, however, automated methods are not keeping pace. A key bottleneck is that most data comparison algorithms today rely on a human expert to specify what ‘features' of the data are relevant for comparison. Here, we propose a new principle for estimating the similarity between the sources of arbitrary data streams, using neither domain knowledge nor learning. We demonstrate the application of this principle to the analysis of data from a number of real-world challenging problems, including the disambiguation of electro-encephalograph patterns pertaining to epileptic seizures, detection of anomalous cardiac activity from heart sound recordings and classification of astronomical objects from raw photometry. In all these cases and without access to any domain knowledge, we demonstrate performance on a par with the accuracy achieved by specialized algorithms and heuristics devised by domain experts. We suggest that data smashing principles may open the door to understanding increasingly complex observations, especially when experts do not know what to look for.

APA, Harvard, Vancouver, ISO, and other styles

22

Shlyk, Irina F. "Cytokine Profile and Endothelial Status in Patients with Coronary Artery Disease and Different Outcomes of Coronary Artery Bypass Grafting." Kuban Scientific Medical Bulletin 26, no. 5 (November 9, 2019): 96–104. http://dx.doi.org/10.25207/1608-6228-2019-26-5-96-104.

Full text

Abstract:

Aim. To assess the cytokine profile and the level of endothelial dysfunction in patients with coronary artery disease (CAD) and different outcomes of coronary artery bypass grafting (CABG).Materials and methods. The study included 95 people, with 22 of them being practically healthy (without CAD). The CAD patients (73) were retrospectively divided into 2 subgroups according to the presence of complications within the first month after the CABG. The first subgroup consisted of 25 patients suffering from complications after CABG, with 48 people making up the second subgroup (no complications after CABG). CABG was performed on a beating heart; bypass grafts were attached during revascularisation. The serum levels of IL-4 and IFN-γ were determined through the enzyme-linked immunosorbent assay (ELISA) using appropriate test systems manufactured by BCM Diagnostics and a Zenyth 340 microplate photometer (Biochrom Ltd). In order to determine the content of endothelin-1 in blood serum, ELISA test systems manufactured by Biomedica were used. The statistical analysis of study results was performed employing the descriptive statistics module of Statistica 12.0 (StatSoft, USA). The mean (M), its error (m), median (Me) and the interquartile range [Q25; Q75] were calculated. In cases when p ≤ 0.05, the results were considered statistically significant.Results. It was revealed that, in the preoperative period, CAD patients from both subgroups exhibited increased levels of endothelin-1 (p = 0.0001) and IFN-γ (p = 0.0001), whereas an increase in IL-4 production was noted only in the first subgroup (p = 0.0001), as compared to the control group. The follow-up revealed that CAD patients with complications after CABG exhibited stable high levels of IL-4 (p > 0.05) and IFN-γ (p > 0.05) during the entire observation period, as compared to the initial values. The content of endothelin-1 in both subgroups increased significantly on the 4th day of observation (p > 0.05) and returned to its initial high values after 1 month.Conclusion. Immune response in CAD patients suffering from complications after CABG develops mainly along the pro-inflammatory pathway and is accompanied by endothelial dysfunction.

APA, Harvard, Vancouver, ISO, and other styles

23

CAO, YUAN-CHENG, and YUAN-DI ZHAO. "EXTRACTION OF ANTHRAQUINONE DERIVATIVES FROM RHUBARB RHIZOMES AND THEIR ANTIBACTERIAL TESTS." Journal of Innovative Optical Health Sciences 04, no. 02 (April 2011): 127–32. http://dx.doi.org/10.1142/s1793545811001290.

Full text

Abstract:

Photometry was employed to study the optimum extraction conditions of anthraquinone derivatives from rhizomes of Rheum officinale Baill in this study. The influences of extraction solvents (chloroform, benzene, ethanol, methanol, and glycerol), acid, and extraction time on the extraction yield were discussed. The results indicate that, to the Rhubarb rhizomes powder with the average particle size 0.18 mm, the conditions of the extraction solvent composed by chloroform, glycerol, and sulfuric acid (20%) in the ratio of 4:1:1 (v:v), the weight of dried Rhubarb to the solvent volume in the ratio of 1:12 (w:v), extraction time of 110 min, the anthraquinone derivatives extraction could achieve the best yield. And the antibacterial tests showed the raw extraction products had the MIC (minimal inhibitory concentration) of 20 μg/mL and 30 μg/mL to Staphylococcus aureus and Escherichia coli, respectively.

APA, Harvard, Vancouver, ISO, and other styles

24

Yu, Tao, Shangbin Chen, Jingying Pan, Conglin Su, and Jun He. "Optical investigations reveal the effects of 2-aminoethyldiphenyl borate on STIM1 puncta formation." Journal of Innovative Optical Health Sciences 11, no. 02 (February 19, 2018): 1850003. http://dx.doi.org/10.1142/s1793545818500037.

Full text

Abstract:

2-Aminoethyldiphenyl borate (2-APB) is the most commonly used pharmacological agent in the study of calcium release-activated channels (CRACs); however, its inhibitory mechanism to CRACs remains unclear. To address this issue, we systematically employed confocal imaging, dual-wavelength excitation photometry and FRET to examine the effects of 2-APB on the dynamic activities and function of STIM1 and Orai1, two key components of CRACs. Imaging results support that there are two signaling pathways (Orai1-independent and Orai1-dependent) for the formation of STIM1 puncta. 2-APB could dose dependently block Orai1-independent but not Orai1-dependent STIM1 puncta formation, despite its obvious inhibition effect on store-operated Ca[Formula: see text] entry (SOCE). In addition, we found that although 2-APB could not visibly alter near plasma membrane CAD-eYFP localization, it could completely block CAD-YFP-induced constitutive Ca[Formula: see text] entry and promote the interaction between Orai1 and CAD by FRET measurements. Therefore, we proposed that inhibitory action of 2-APB on SOCE might attribute to its direct inhibitory effects on Orai1 channel itself, but not the interference on puncta formation between STIM1 and Orai1.

APA, Harvard, Vancouver, ISO, and other styles

25

El-Khatib, Walid, Virginia Haynes, and Ayman Noreddin. "A High-Throughput In Vitro Model Illustrating Potential Microbiological Interactions During Treatment of Pseudomonas Aeruginosa Biofilm Associated Infections." Journal of Medical Devices 2, no. 2 (June 1, 2008). http://dx.doi.org/10.1115/1.2927395.

Full text

Abstract:

Objective: Amend a real-time, high-throughput method of bacterial growth detection for use as a model of biofilm response to co-administered pharmaceuticals during the treatment of devise associated infections. Background: Biofilms are the root etiology for chronic infections, particularly in regard to infections in patients with implanted medical devices. Calcium channel blockers (CCBs) are used for control of hypertension and angina and are commonly prescribed to elderly patients. We address potential interference of commonly prescribed CCBs with levofloxacin for treatment of Pseudomonas aeruginosa biofilms. Methods: Inoculum of 1–3×106CFU∕mL in the log phase were seeded into each well of a polystyrene plate. Biofilms developed over 6h at 37°C, was washed and medium containing various CCBs plus levofloxacin was added to the biofilm. OD measurements were obtained at 1h intervals over 90h at 37°C. Changes in turbidity were kinetically measured with a vertical photometer with a wide-band filter. Results: Mibefradil and diltiazem appear to be strongly antagonistic toward levofloxacin where both of them decrease antibiofilm effect of levofloxacin and they encourage the selection of resistant mutants from biofilm. Discussion: Implanted medical devices are quite common and are subjected to biofilm infections. Increasing multi-drug resistance underscores the need to conserve current antibiotics by judicious use. This necessitates consideration of evidence regarding antagonistic or synergistic activity of commonly prescribed drugs of different classes toward commonly used antibiotics. The combinations described here show vital and previously unreported effects of some CCBs when co-prescribed with levofloxacin on Pseudomonas aeruginosa biofilm.

APA, Harvard, Vancouver, ISO, and other styles

26

Jakupco, Nicholas, Francis Nwaneri, and Michael Mirro. "Pilot Study to investigate Home Potassium testing in Heart Failure." Proceedings of IMPRS 3 (December 15, 2020). http://dx.doi.org/10.18060/24649.

Full text

Abstract:

Background and hypothesis: Heart failure (HF) is one of the leading causes of death in the United States. Normal potassium range is 3.5 to 5 mEq/L. Low potassium level is associated with fatal dysrhythmia, and elevated potassium levels result in slow cardiac rhythms and asystole. Current venipuncture methods used for potassium testing are complicated with hemolysis, which create false potassium results. Our study objective is assessing the effectiveness of an at home device that would enable HF patients to test potassium levels frequently to avoid any complications as it relates to dyskalemia. We hypothesize that by utilizing a home testing solution, patients can develop a home HF management strategy to improve health outcomes. Experimental Design or Project Methods: Patients diagnosed with HF will be recruited from Parkview Physicians Group – Cardiology. A venipuncture and a finger stick sample will be collected simultaneously, and their serum potassium levels will be analyzed. Venipuncture blood will be analyzed by ion-selective electrode (ISE) and flame photometry analyses. Finger stick blood will be analyzed by a novel Blaire Biomedical device. Surveys about the device will be given to both patients and clinicians. Linear regressions comparing the Blaire Biomedical results to both the ISE and flame photometry results will be created. Results: The r-values for the regressions will be analyzed. An r-value close to 1 would indicate that the results are directly correlated and clinically equivalent. Results of the surveys will be used to gauge interest in the device. Conclusion and Potential Impact: This study will establish a more efficient way for HF patients to measure potassium levels and ensure levels stay in the range of 3.5 to 5 mEq/L. This device will assist in reducing potassium imbalance complications, which will translate to a decrease in mortality in HF patients as it relates to dyskalemia.

APA, Harvard, Vancouver, ISO, and other styles

27

Kuvaldin, E. "Counting Method for Measuring and Linearity Checking Photometry Devices." Measurement Science Review 10, no. 2 (January 1, 2010). http://dx.doi.org/10.2478/v10048-010-0010-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Czepita, Maciej. "Aperture photometry measurements of melanin particles in Krukenberg spindles of the cornea in pigment dispersion syndrome." Technology and Health Care, June 25, 2021, 1–8. http://dx.doi.org/10.3233/thc-202501.

Full text

Abstract:

BACKGROUND: Quantification of melanin pigment release in pigment dispersion syndrome as well as observations of melanin brightness changes can be valuable information in the management of this rare ocular disease. OBJECTIVES: Previous studies have focused on examining the iris pigment epithelium and aqueous humor. Therefore, the aim of this study was to examine the cornea. METHODS: A novel technique was developed for this purpose based on aperture photometry. Slit lamp digital video images of the cornea were recorded. A single frame from each video recording based on the quality was chosen for further processing and analysis. Aperture photometry was performed with AstroImageJ open source software. Aperture selection was performed automatically. Melanin particles displaying a signal-to-noise ratio above 20 were analyzed. RESULTS: A total of 16 melanin particles from the right eye of the patient participating in the study were detected and a further 9 melanin particles from the left eye. The examined area of the cornea measured 348 × 348 pixels in the image. Brightness differed by as much as 8.98 × among particles in the right eye and 2.03 × in the left eye. CONCLUSIONS: It seems feasible for this new method to be potentially used in the monitoring of patients with pigment dispersion syndrome and pigmentary glaucoma as well as in other ocular diseases.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Biomedical photometer'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles