scholarly journals RELATION OF OXYGEN TENSION AND TEMPERATURE TO THE TIME OF REDUCTION OF CYTOCHROME

1935 ◽  
Vol 19 (2) ◽  
pp. 339-350 ◽  
Author(s):  
T. J. B. Stier
Keyword(s):  
Absorption Band ◽  
Linear Relation ◽  
Optical Method ◽  
Respiratory Activity ◽  
Yeast Cells ◽  
O2 Consumption ◽  
Average Difference ◽  
Absorption Bands ◽  
Experimental Conditions ◽  
Reduction Time

The time for the appearance of the cytochrome C absorption band after shaking a suspension of bakers' yeast with various O2-N2 mixtures was determined at each of six temperatures. At each temperature a linear relation between this interval—called the reduction time—and O2 tension was found. It was shown: 1. That under our experimental conditions, absorption bands of cytochrome were seen when the O2 tension of the suspension was reduced to, or below, a certain pressure which was found to be specific for each temperature (this pressure is provisionally considered to be identical with or very near to the "critical O2 tension" usually found in QOO2-O2-tension relationships); 2. That the x-axis intercept obtained from the reduction time - O2-tension plot gives the value of the "critical" O2 pressure at each temperature; 3. That the O2 tension within the suspension is reduced by the respiratory activity of the yeast cells. An equation describing these observations is given and is used in calculating rates of O2 consumption from measurements of reduction time of cytochrome. The average difference between the calculated values and the manometric measurements of QOO2 was found to be 6.6 per cent. A rapid optical method of measuring rates of O2 consumption based on the findings of these experiments is proposed for use with cytochrome-containing microorganisms.

First Nano-Infrared Spectroscopy and Imaging Measurements of Single Phospholipid Bilayers

2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Absorption Band ◽  
Spectral Region ◽  
Near Field ◽  
Phospholipid Bilayers ◽  
Model Systems ◽  
Absorption Bands ◽  
Protein Complement ◽  
20 Nm

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>

scholarly journals OLIGOMERIC SILSESQUIOXANES COMBINING AZO- AND FLUORESCENT DYES IN ORGANIC SHELL

2019 ◽  
Vol 85 (4) ◽  
pp. 71-80
Author(s):  
Mariana Gumenna ◽  
Nina Klimenko ◽  
Alexandr Stryutsky ◽  
Alexandr Shevchuk ◽  
Viktor Kravchenko ◽  
...  
Keyword(s):  
Absorption Band ◽  
Rhodamine B ◽  
Fluorescent Dyes ◽  
Hydroxyl Groups ◽  
Uv Spectrum ◽  
Absorption Bands ◽  
Organic Shell ◽  
Similar Band ◽  
Inorganic Nanocomposites ◽  
Epoxy Groups

A method for the synthesis of reactive oligomeric silsesquioxanes, combining fragments of azo dye 4-(phenylazo)phenol and fluorescent dye Rhodamine B in various proportions in an organic shell was developed. These compounds were obtained by the reaction between the oligosilsesquioxane nanoparticles consisting of a mixture of linear, branched, ladder and polyhedral structures with epoxy groups in an organic frame (OSS–Ep) and the dyes. The structure of the synthesized substances was characterized by the methods of IR and 1H NMR spectroscopy. The UV-Vis spectra of OSS–Pp–Rh in DMF solution contain absorption bands characteristic of both acidic (560 and 350 nm) and lactone (in the range of 318–326 nm) forms of Rhodamine B. The absorption band of 4-(phenylazo) phenol fragments corresponding to π−π* transition is observed at 348 nm and overlaps the absorption band of Rhodamine B at 350 nm.The intensity of the absorption bands of fragments of various dyes depends on their content in organic frame of the silsesquioxane core. The intensity of the absorption bands at 348 nm and at 560 nm increases with an increase in the content of 4-(phenylazo)phenol and Rhodamine B correspondingly.It should be noted that when using DMF as a solvent the absorption band corresponding to acidic form of Rhodamine B at 560 nm in the UV-Vis spectra of the compounds obtained is more intense than similar band in the spectrum of the original Rhodamine B. Therefore, the attachment of Rhodamine B to the silsesquioxane core of oligomeric silsesquioxanes mixture does not have a significant effect on the position of absorption maxima in the UV-spectrum and prevents dye’s fragments from converting to the colorless lactone form. In the fluorescence spectra of OSS–Pp–Rh obtained using DMF as a solvent a peak at λ max = 592 nm (λex= 520 nm) is observed. The position of the fluorescence peak and its intensity in the spectra at the same optical density of the medium practically do not depend on the ratio of fragments of 4-(phenylazo)phenol and Rhodamine B in organic frame of OSS–Pp–Rh.  The combination of two different chromophores in organic shell of the silsesquioxane core broadens the range of absorbed light and the change of their ratio allows to adjust the absorption intensity in a certain area. The presence of hydroxyl groups makes it possible to introduce the obtained compounds into the composition of polymeric organic-inorganic nanocomposites by covalent bonding.

scholarly journals Local vibrational modes of vacancy-oxygen-related complexes at room temperature

2020 ◽  
Vol 56 (4) ◽  
pp. 480-487
Author(s):  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
L. I. Murin
Keyword(s):  
Absorption Band ◽  
Room Temperature ◽  
Clear Correlation ◽  
Ir Absorption ◽  
Oxygen Impurity ◽  
Interstitial Oxygen ◽  
Vibrational Modes ◽  
Oxygen Defect ◽  
Absorption Bands ◽  
Local Vibrational Modes

The isotopic content of natural silicon (28Si (92.23 %), 29Si (4.68 %) и 30Si (3.09 %)) affects noticeably the shape of IR absorption bands related to the oxygen impurity atoms. In the present work an attempt is undertaken to determine the positions of local vibrational modes (LVMs), related to quasimolecules 28Si16OS29Si and 28Si16OS30Si (OS – substitutional oxygen atom), for the absorption spectra measured at room temperature. An estimation of the isotopic shifts of corresponding modes is done by fitting the shape of the experimentally measured absorption band related to the vacancy–oxygen center in irradiated Si crystals. The LVM isotope shifts are found to be equal 2,2 ± 0.25 cm–1 for 28Si-16OS29Si and 4,3 ± 0,9 см–1 for 28Si-16OS30Si in relation to the basic band due to 28Si-16OS28Si, and the full width at half maximum of the A-center absorption band (28Si-16OS28Si) is 5,3 ± 0.25 cm–1. By means of infrared absorption spectroscopy a clear correlation between the disappearance of the divacancy (V2) in the temperature range 200–275 ºС and appearance of two absorption bands with their maxima at 825.8 and 839.2 cm–1 in irradiated oxygen-rich Si crystals is found. The band positioned at 825.8 cm–1 is assigned to a divacancy-oxygen defect V2O formed via an interaction of mobile V2 with interstitial oxygen (Oi ) atoms. The 839.2 cm–1 band is much more pronounced in neutron irradiated samples as compared to samples irradiated with electrons. We argue that it is related to a trivacancy–oxygen defect (V3O) formed via an interaction of mobile V3 with Oi atoms.

Factors regulating basal metabolism of the isolated perfused rabbit heart

1986 ◽  
Vol 250 (6) ◽  
pp. H998-H1007 ◽  
Author(s):  
C. L. Gibbs ◽  
G. Kotsanas
Keyword(s):  
Metabolic Rate ◽  
Coronary Flow ◽  
Constant Pressure ◽  
Rabbit Heart ◽  
Basal Metabolism ◽  
Papillary Muscles ◽  
O2 Consumption ◽  
Calcium Depletion ◽  
Experimental Conditions ◽  
High K

Basal metabolism has been measured in isolated whole hearts from rabbits and compared with myothermic and polarographic measurements on isolated papillary muscles. Hearts were perfused at constant pressure (Langendorff method) using a modified Krebs-Henseleit solution (KH) with glucose as substrate. Higher levels of basal O2 consumption (MVO2) and coronary flow (CF) were observed when arrest was induced by calcium depletion (low Ca; 0.1 mM CaCl2, 10.0 mM KCl) rather than by potassium excess (high K; 30.0 mM KCl). The metabolic rate of high K arrested hearts was close to earlier myothermic estimates (J. Mol. Cell. Cardiol. 16: 953-962, 1984); polarographic values, however, were about twofold higher, and somewhat higher than the value obtained in low Ca arrested hearts. The addition of erythrocytes, albumin, or dextran significantly reduced CF but did not substantially alter basal MVO2. Basal metabolic rate was substrate- and O2 tension-dependent, and under all experimental conditions there was linear relationship between MVO2 and CF. Extrapolations to zero flow showed that the basal MVO2 values so obtained were similar in low Ca or high K and were not altered by the presence of erythrocytes. Our results show that there are several factors regulating basal metabolism.

Oxygen consumption and ventilation of dogs during passive and active exercise

1977 ◽  
Vol 42 (6) ◽  
pp. 923-927 ◽  
Author(s):  
A. K. Russo ◽  
J. Tarasantchi ◽  
M. A. Griggio
Keyword(s):  
Minute Volume ◽  
O2 Consumption ◽  
Experimental Conditions ◽  
Pentobarbital Sodium ◽  
Passive Exercise ◽  
Respiratory Parameters ◽  
Ventilatory Equivalent ◽  
Before And After ◽  
Proportional Increase ◽  
Passive Muscle

A comparison was made between the influence of passive and active exercise on the energy metabolism (EM) and respiratory parameters (RP) of dogs: respiratory minute volume and ventilatory equivalent for O2. Passive exercise was performed in 24 dogs, anesthetized with pentobarbital sodium and morphine or ketamine hydrochloride and pentobarbital sodium, by moving the four limbs at constant frequencies of 25, 45, or 80 movements/min before and after curarization. Active exercise was induced in 35 animals by electric stimulation of the quadriceps and triceps muscles or of the distal ends of femoral and radial nerves at the same frequencies previously indicated. Values obtained for EM and RP during passive exercise were not significantly different from those obtained during resting conditions; active exercise caused a significant increase which was directly proportional to the frequencies of limb movement. Our results indicate that passive muscle movement induces no alteration in O2 consumption and the possible relfexes generated in these experimental conditions were not apparently important on ventilatory control. In active movements, over the range of the frequencies studied, there is a proportional increase in O2 consumption followed by a corresponding increase in ventilation.

scholarly journals A role for adenosine in metabolic depression in the marine invertebrate Sipunculus nudus

1997 ◽  
Vol 272 (1) ◽  
pp. R350-R356 ◽  
Author(s):  
A. Reipschlager ◽  
G. E. Nilsson ◽  
H. O. Portner
Keyword(s):  
Body Wall ◽  
Marine Invertebrate ◽  
Coelomic Fluid ◽  
Metabolic Depression ◽  
O2 Consumption ◽  
Experimental Conditions ◽  
Indwelling Catheter ◽  
Sipunculus Nudus ◽  
Body Wall Musculature ◽  
Concentration Changes

Involvement of neurotransmitters in metabolic depression under hypoxia and hypercapnia was examined in Sipunculus nudus. Concentration changes of several putative neurotransmitters in nervous tissue during anoxic or hypercapnic exposure or during combined anoxia and hypercapnia were determined. Among amino acids (gamma-aminobutyric acid, glutamate, glycine, taurine, serine, and aspartate) and monoamines (serotonin, dopamine, and norepinephrine), some changes were significant, but none were consistent with metabolic depression under all experimental conditions applied. Only the neuromodulator adenosine displayed concentration changes in accordance with metabolic depression under all experimental conditions. Levels increased during anoxia, during hypercapnia, and to an even greater extent during anoxic hypercapnia. Adenosine infusions into coelomic fluid via an indwelling catheter induced a significant depression of the normocapnic rate of O2 consumption from 0.36 +/- 0.04 to a minimum of 0.24 +/- 0.02 (SE) mumol.g-1.h-1 after 90 min (n = 6). Application of the adenosine antagonist theophylline caused a transient rise in O2 consumption 30 min after infusion during hypercapnia but not during normocapnia. Effects of adenosine and theophylline were observed in intact individuals but not in isolated body wall musculature. The results provide evidence for a role of adenosine in inducing metabolic depression in S. nudus, probably through the established effects of decreasing neuronal excitability and neurotransmitter release. In consideration of our previous finding that metabolic depression in isolated body wall musculature was elicited by extracellular acidosis, it is concluded that central and cellular mechanisms combine to contribute to the overall reduction in metabolic rate in S. nudus.

Chlorine Solutions in Molten Alkali Chlorides

2007 ◽  
Vol 62 (3-4) ◽  
pp. 205-212 ◽  
Author(s):  
Artem Kolobov ◽  
Vladimir Khokhlov ◽  
Alexei Potapov ◽  
Victor Kochedykov
Keyword(s):  
Absorption Band ◽  
Molten Salt ◽  
Electronic Absorption ◽  
Absorption Maximum ◽  
Electronic Absorption Spectra ◽  
Absorption Bands ◽  
Short Waves ◽  
Wide Absorption Band ◽  
Alkali Chlorides ◽  
Saturated Solutions

Electronic absorption spectra of gaseous chlorine and their saturated solutions in molten alkali chlorides were studied in wide ranges of temperature and wavelength. It was found that gaseous chlorine has a wide absorption band between 20 000 and 43 500 cm−1. There is a tendency to both widening of the band and shifting of the absorption maximum to the short-waves region with rising temperature.The absorption bands of saturated solutions of chlorine in all molten alkali chlorides show a maximum in the neighborhood of 30 000 cm−1. A good correlation was found between the optical density of molten salt-Cl2 systems and the solubility of chlorine.

Trapped Electrons and Radicals in γ-Irradiated Propylene Carbonate Glasses

1972 ◽  
Vol 50 (6) ◽  
pp. 782-791 ◽  
Author(s):  
Eric A. Shaede
Keyword(s):  
New Species ◽  
Absorption Band ◽  
Propylene Carbonate ◽  
Radical Anion ◽  
The Other ◽  
Γ Irradiation ◽  
Absorption Bands ◽  
Trapped Electrons ◽  
Optical Absorption Band ◽  
Positive Ions

Radicals formed by γ-irradiation of propylene carbonate (PC) glasses at 77 °K were studied by e.s.r. and optical spectroscopy. Trapped electrons were identified by their narrow (ΔHms = 4.5 G) Gaussian e.s.r. line at g = 2.0028 which was completely resolved from the radical spectrum. The trapped electrons were unstable at 77 °K. They decayed fairly rapidly via a process exhibiting non-homogeneous kinetics believed to be reaction with positive ions. The temperature dependence of the e.s.r. spectra of the other radicals formed is discussed although conclusive assignment of the lines could not be made.Ultraviolet photolysis of the radicals in the irradiated PC glasses produced new species identified as HCO, CO3−, and CH3 by their characteristic e.s.r. spectra. In addition, a complex optical absorption band in the 500–750 nm region was assigned to a combination of the absorption bands of the CO3− radical anion and the HCO radical.

The reactivity of platinum hydrides in the selective hydrogenation of acetic acid over Pt-ReOx/TiO2 catalysts

2020 ◽  
Vol 20 (6) ◽  
pp. 426-432
Author(s):  
N. V. Makolkin ◽  
H. U. Kim ◽  
E. A. Paukshtis ◽  
J. Jae ◽  
B. S. Bal’zhinimaev
Keyword(s):  
Acetic Acid ◽  
Absorption Band ◽  
Electronic State ◽  
Carboxylic Acids ◽  
Selective Hydrogenation ◽  
High Reactivity ◽  
Absorption Bands ◽  
In Situ Drifts ◽  
High Frequencies

In situ DRIFTS was employed to investigate the reaction of hydrogen with supported subnanometer Pt-ReOx species that are active in the hydrogenation of carboxylic acids. Absorption bands of platinum hydrides in the region of 2025–2043 cm–1 were detected; high reactivity of the hydrides toward the adsorbed acetic acid was revealed. In the process, the absorption band of platinum hydride shifted to high frequencies and increased in intensity due to the influence of adjacent acetates on the electronic state of platinum. It was found that in a hydrogen medium the intensity of platinum hydride bands sharply increases after the adsorption of acetic acid and then gradually decreases owing to the reaction of the hydrides with surface acetates.

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