scholarly journals Analysis of Emission Infrared Spectra of Protein Solutions in Low Concentrations

2020 ◽  
Vol 8 ◽  
Author(s):  
Nikita Penkov ◽  
Nadezda Penkova
Keyword(s):  
Emission Spectra ◽  
Infrared Emission ◽  
Water Control ◽  
Three Solutions ◽  
Buffer Solution ◽  
Radiation Level ◽  
Low Concentration ◽  
Spectral Bands ◽  
Distant Effect ◽  
Low Concentrations

In this work, based on the method of infrared emission spectroscopy, the study of emission spectra of interferon-gamma (IFNγ) solution in a mixture or surrounded by three low-concentration solutions (IFNγ, antibodies to IFNγ, glycine buffer) or water control was performed. First of all, the solutions of low concentrations themselves were studied. It was shown that low-concentration solutions of IFNγ and antibodies to IFNγ had lower emission intensity in three spectral bands near 800, 1,300 and 2000 cm−1 compared to water control. Glycine buffer solution had a radiation level indistinguishable from that of the control. In this work, the effect of adding these low-concentration solutions to IFNγ (1 mg/ml) was compared to the effect of adding water control to IFNγ. All solutions or water were added in 10% (v/v). It was found that adding each of the three test solutions induced an increase in the radiation intensity of the IFNγ solution in the spectral range of 400–1700 cm−1 (compared to the IFNγ solution with control spike). It was also tested whether the radiation of the studied low-concentration solutions surrounding the IFNγ solution (1 mg/ml) affected the IFNγ radiation. The measurement results were compared to the data obtained for IFNγ surrounded by water control. All three solutions were found to exert a distant effect on the IFNγ solution (1 mg/ml), which was manifested in a decrease in the intensity of its radiation near 1,000 and 1,500 cm−1 compared to the control solution of IFNγ. Thus, the emission spectra of low-concentration aqueous solutions were measured for the first time, and differences in the emission spectra of the IFNγ solution depending on low-concentration additives and the environment were shown. The paper interprets the observed differences and discusses possible mechanisms underlying the observed phenomena.

Infrared Emission Spectra of Elastohydrodynamic Contacts

1976 ◽  
Vol 98 (2) ◽  
pp. 230-235 ◽  
Author(s):  
J. L. Lauer ◽  
M. E. Peterkin
Keyword(s):  
Contact Region ◽  
Radiant Energy ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Operating Conditions ◽  
Test Fluid ◽  
Two Fluids ◽  
Spectral Bands ◽  
Ball Surface ◽  
Lower Fluid

A small diamond disk mounted as a window in a steel plate was covered with test fluid, and a weighted steel ball was rotated over the window so as to form a sliding elastohydrodynamic (EHD) contact region. Some of the radiant energy generated in this region, both in the fluid and at the boundaries, passed through the window into an infrared interferometer, giving rise to an emission spectrum. This spectrum could be separated into contributions from the fluid and from the ball surface, making it possible, by appropriate calibrations, to estimate their temperatures separately under operating conditions. Moreover, the shape of the discrete spectral bands of the fluid permitted some inferences on its state. Two fluids were studied under identical mechanical conditions, a polyester and a naphthenic oil, each containing an equal amount of polymethylstyrene as a spectral indicator. Differences of band intensity, band width, and frequency could, therefore, be attributed to differences in the behavior of the base fluid. The principal results were much lower fluid temperatures and lower metal surface temperatures when the polyester was used than when the naphthenic oil was similarly used. Polyester films were also thicker and of higher density than naphthenic oil films under the same conditions. This work is only the beginning of a comprehensive study of EHD contacts by infrared spectroscopy, but the results already achieved lead to interesting speculations on the mechanisms of EHD processes, which further study is expected to elucidate.

Molecular Transformations in DNA under the Influence of UV-radiation

2020 ◽  
Vol 04 ◽  
Author(s):  
Vigen G. Barkhudaryan ◽  
Gayane V. Ananyan ◽  
Nelli H. Karapetyan
Keyword(s):  
Uv Radiation ◽  
Uv Irradiation ◽  
Absorption Spectroscopy ◽  
Calf Thymus Dna ◽  
Dilute Solutions ◽  
Concentrated Solutions ◽  
Buffer Solution ◽  
Low Concentration ◽  
Calf Thymus ◽  
Dna Solutions

Background: The processes of destruction and crosslinking of macromolecules occur simultaneously under the influence of ultraviolet (UV) radiation in synthetic polymers, dry DNA and their concentrated solutions. Objective: The effect of UV radiation on calf thymus DNA in dilute solutions subjected to UV- irradiation was studied in this work. Method: The calf thymus DNA was studied in dilute solutions using viscometry, absorption spectroscopy and electrophoresis. Results: It was shown, that at a low concentration of DNA in the buffer solution ([DNA] = 85 μg / ml) under the influence of UV radiation, the processes of destruction of macromolecules and an increase in their flexibility predominate, which is accompanied by a gradual decrease in the viscosity of their solution. In addition, due to the low concentration of the solution, intramolecular crosslinking of macromolecules predominates, which also reduces their size and, consequently, the viscosity of the solution. Conclusion: It was concluded, that in dilute DNA solutions, due to the predominance of the processes of intramolecular crosslinking of macromolecules over intermolecular, only constant processes of decreasing the sizes of DNA macromolecules occur. As a result, its solubility remains virtually unchanged during UV irradiation. The described comments are also excellently confirmed by the results of absorption spectroscopy and electrophoresis

The Use of Ratio-Recording Interferometry for the Measurement of Infrared Emission Spectra: Applications to Oxide Films on Copper Surfaces

1975 ◽  
Vol 29 (6) ◽  
pp. 496-500 ◽  
Author(s):  
D. Kember ◽  
N. Sheppard
Keyword(s):  
Emission Spectra ◽  
Black Body ◽  
Infrared Emission ◽  
Thin Layers ◽  
Oxide Surface ◽  
Surface Layers ◽  
Selective Reflection ◽  
Copper Surfaces ◽  
Emission And Absorption Spectra ◽  
Direct Correspondence

Infrared emission spectra from metal samples with oxide surface layers are shown to be very advantageously studied using the spectrum-ratioing facility of a recording infrared interferometer. The emission from a given sample is ratioed against that from a black-body emitter at the same temperature so as to give emittance as a function of wavenumber directly. This method has very useful application to irregularly shaped metal emitters. In the absence of selective reflection there is a direct correspondence between emission and absorption spectra for thin layers of an emitting substance. However, the presence of selective reflection leads to reduced emission and to considerable differences in the appearance of “absorption” and emission spectra in regions of strong absorption. Emission spectra obtained from copper plates heated, above 150°C, for different periods in air are shown clearly to indicate the presence of cuprous, Cu(I), and cupric, Cu(II), oxides in the surface layer.

Infrared emission spectra of BeH2 and BeD2

2003 ◽  
Vol 118 (8) ◽  
pp. 3622-3627 ◽  
Author(s):  
A. Shayesteh ◽  
K. Tereszchuk ◽  
P. F. Bernath ◽  
R. Colin
Keyword(s):  
Emission Spectra ◽  
Infrared Emission

Temperature Gradients Through EHD Films and Molecular Alignment Evidenced By Infrared Spectroscopy

1981 ◽  
Vol 103 (1) ◽  
pp. 65-73 ◽  
Author(s):  
V. W. King ◽  
J. L. Lauer
Keyword(s):  
Absorption Spectrum ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Molecular Alignment ◽  
Temperature Gradients ◽  
Spectral Change ◽  
Continuum Source ◽  
Polyphenyl Ether ◽  
Elementary Analysis ◽  
Gap Width

Partial and complete emission band reversals have been observed in the infrared emission spectra from portions of operating sliding contacts. An elementary analysis has been carried out to show that partial reversals are due to temperature gradients in the fluid film—the film acts both as a radiation-emitter and absorber, and that total reversals—an emission spectrum appears as an absorption spectrum—are likely to be due to a continuum source, such as hot solid asperities. The total energy radiated under the latter conditions exceeds that under the others. A decrease in gap width with increased load was accompanied by a dramatic spectral change in the case of 5P4E polyphenyl ether, which is indicative of molecular alignment.

Reduction of Escherichia coli O157:H7 Counts on Whole Fresh Apples by Treatment with Sanitizers

2000 ◽  
Vol 63 (6) ◽  
pp. 703-708 ◽  
Author(s):  
MARCY A. WISNIEWSKY ◽  
BONITA A. GLATZ ◽  
MARK L. GLEASON ◽  
CHERYLL A. REITMEIER
Keyword(s):  
Escherichia Coli ◽  
Chlorine Dioxide ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
Water Control ◽  
Buffer Solution ◽  
E Coli ◽  
Log Reduction

The objectives of this study were to determine if washing of whole apples with solutions of three different sanitizers (peroxyacetic acid, chlorine dioxide, or a chlorine-phosphate buffer solution) could reduce a contaminating nonpathogenic Escherichia coli O157:H7 population by 5 logs and at what sanitizer concentration and wash time such a reduction could be achieved. Sanitizers were tested at 1, 2, 4, 8, and 16 times the manufacturer's recommended concentration at wash times of 5, 10, and 15 min. Whole, sound Braeburn apples were inoculated with approximately 1 × 108 or 7 × 106 CFU per apple, stored for 24 h, then washed with sterile water (control) or with sanitizers for the prescribed time. Recovered bacteria were enumerated on trypticase soy agar. Washing with water alone reduced the recoverable population by almost 2 logs from the starting population; this can be attributed to physical removal of organisms from the apple surface. No sanitizer, when used at the recommended concentration, reduced the recovered E. coli population by 5 logs under the test conditions. The most effective sanitizer, peroxyacetic acid, achieved a 5-log reduction when used at 2.1 to 14 times its recommended concentration, depending on the length of the wash time. The chlorine-phosphate buffer solution reduced the population by 5 logs when used at 3 to 15 times its recommended concentration, depending on wash time. At no concentration or wash time tested did chlorine dioxide achieve the 5-log reduction.

scholarly journals Modeling the Anharmonic Infrared Emission Spectra of PAHs: Application to the Pyrene Cation

2020 ◽  
pp. 95-102
Author(s):  
M. Basire ◽  
P. Parneix ◽  
T. Pino ◽  
Ph. Bréchignac ◽  
F. Calvo
Keyword(s):  
Emission Spectra ◽  
Infrared Emission

scholarly journals Low Concentrations of Chlorhexidine Inhibit the Formation and Structural Integrity of Enzyme-Treated Multispecies Oral Biofilms

2021 ◽  
Vol 12 ◽  
Author(s):  
Kay Andrin Gränicher ◽  
Lamprini Karygianni ◽  
Thomas Attin ◽  
Thomas Thurnheer
Keyword(s):  
Structural Integrity ◽  
Fluorescent Dyes ◽  
Combined Treatment ◽  
Extracellular Proteins ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Anaerobic Growth ◽  
Low Concentration ◽  
Low Concentrations ◽  
Dental Hard Tissues

The self-produced matrix of biofilms, consisting of extracellular polymeric substances, plays an important role in biofilm adhesion to surfaces and the structural integrity of biofilms. In dentistry, biofilms cause multiple diseases such as caries, periodontitis, and pulpitis. Disruption of these biofilms adhering to dental hard tissues may pose a major challenge since biofilms show higher tolerance to antimicrobials and antibiotics than planktonic cells. In this study, the effect of low concentrations of chlorhexidine (CHX) on enzyme-treated multispecies oral biofilm was investigated in an in vitro model. Six-species biofilms were enzymatically treated by anaerobic growth in a medium containing DNase I and proteinase K. Biofilms were exposed to a low concentration of CHX at defined time points. After 64h, biofilms were either harvested and quantified by cultural analyses or stained for confocal laser scanning microscopy (CLSM) analyses using either Live/Dead kit or different fluorescent dyes. A mixture of YoPro1 and SYTOX™ Green, Fluorescent Brightener 28 (Calcofluor), and SYPRO™ Ruby Protein Gel Stain was used to stain total DNA, exopolysaccharides, and extracellular proteins, respectively. Extracellular DNA (eDNA) was visualized via an indirect immunofluorescence assay (Mouse anti-DNA IgG, Goat anti-Mouse IgG, Streptavidin-Cy3). Overall, the total colony-forming units significantly decreased after combined treatment with a low concentration of CHX and enzymes compared to the group treated with CHX alone (p<0.001). These findings also apply to five species individually (Streptococcus mutans, Streptococcus oralis, Actinomyces oris, Veillonella dispar, and Candida albicans) occurring in the biofilms, with Fusobacterium nucleatum being the only exception. Furthermore, CLSM images showed less dense biofilms and a reduction in cell numbers after combined treatment compared to the group without enzymes. The combination of enzymes capable of disturbing the matrix integrity with antimicrobial agents thus appears to be a promising approach for biofilm disruption and killing.

Gas Turbine Exhaust Emissions Monitoring Using Nonintrusive Infrared Spectroscopy

1998 ◽  
Vol 120 (3) ◽  
pp. 514-518 ◽  
Author(s):  
M. Hilton ◽  
A. H. Lettington ◽  
C. W. Wilson
Keyword(s):  
Gas Turbine ◽  
Molecular Species ◽  
Tomographic Reconstruction ◽  
Emission Spectra ◽  
Exhaust Emissions ◽  
Infrared Emission ◽  
High Spectral Resolution ◽  
Rotational Line ◽  
Spectroscopic Techniques ◽  
Reconstruction Procedure

Infrared (IR) spectra of the exhaust emissions from a static gas turbine engine have been studied using Fourier Transform (FT) spectroscopic techniques. Passive detection of the infrared emission from remote (range ∼ 3 m) hot exhaust gases was obtained nonintrusively using a high spectral resolution (0.25 cm−1) FTIR spectrometer. Remote gas temperatures were determined from their emission spectra using the total radiant flux method or by analysis of rotational line structure. The HITRAN database of atmospheric species was used to model the emission from gas mixtures at the relevant temperatures. The spatial distribution of molecular species across a section transverse to the exhaust plume ∼10 cm downstream of the jet pipe nozzle was studied using a tomographic reconstruction procedure. Spectra of the infrared emission from the plume were taken along a number of transverse lines of sight from the centerline of the engine outwards. A mathematical matrix inversion technique was applied to reconstruct the molecular concentrations of CO and CO2 in concentric regions about the centerline. Quantitative measurement of the molecular species concentrations determined nonintrusively were compared with results from conventional extractive sampling techniques.

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