scholarly journals THE PIGMENT-PROTEIN COMPOUND IN PHOTOSYNTHETIC BACTERIA

1940 ◽  
Vol 23 (4) ◽  
pp. 483-494 ◽  
Author(s):  
C. S. French
Keyword(s):  
Spectral Region ◽  
Photosynthetic Bacteria ◽  
Water Soluble ◽  
Absorption Curve ◽  
Absorption Bands ◽  
Soluble Cell

Absorption curves have been obtained in the spectral region of 450 to 900 mµ for the water soluble cell juice of four species of photosynthetic bacteria, Spirillum rubrum (strain S1), Rhodovibrio sp. (strain Gaffron), Phaeomonas sp. (strain Delft), and Streptococcus varians (strains C11 and orig.). These curves all show maxima at 790 and 590 mµ due to bacteriochlorophyll, whose highest band, however, occurs at 875, 855, or 840 mµ depending on the species. The bacteria that appear red rather than brown have a band at 550 mµ due to a carotinoid pigment. An absolute absorption curve of bacteriophaeophytin has maxima at 530 and 750 mµ. The extraction of cell juice by supersonic vibration does not change the position of the absorption bands or of the light absorbing capacity of the pigment.

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>

Excitonic Bands in the Optical Absorption Spectra of A3MX6 and A3M2X9 (A = MeNH3, Me2NH2, Me3NH, Me4N; M = Bi, Sb; X = Cl, Br, I)

1994 ◽  
Vol 49 (6) ◽  
pp. 849-851 ◽  
Author(s):  
G. C. Papavassiliou ◽  
I. B. Koutselas
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Spectral Region ◽  
Visible Spectral Region ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Uv Visible ◽  
Low Dimensional

The title compounds (natural low-dimensional semiconductors) show strong excitonic optical absorption bands in the UV-visible spectral region, because of the dielectric confinement of excitons. as in the cases of other similar systems based on PbX2-4, SnX2-4. PtI - X - PtIV-X , Cdx,Sy-clusters etc

scholarly journals Coccidioides immitis Vaccine: Potential of an Alkali-Soluble, Water-Soluble Cell Wall Antigen

1983 ◽  
Vol 39 (1) ◽  
pp. 473-475 ◽  
Author(s):  
Grace Lecara ◽  
Rebecca A. Cox ◽  
Russell B. Simpson
Keyword(s):  
Cell Wall ◽  
Water Soluble ◽  
Coccidioides Immitis ◽  
Soluble Cell ◽  
Vaccine Potential

An acidic water-soluble cell wall polysaccharide: a chemotaxonomic marker for Fusarium and Gibberella

2000 ◽  
Vol 104 (5) ◽  
pp. 603-610 ◽  
Author(s):  
O. Ahrazem ◽  
B. Gómez-Miranda ◽  
A. Prieto ◽  
I. Barasoaín ◽  
M. Bernabé ◽  
...  
Keyword(s):  
Cell Wall ◽  
Water Soluble ◽  
Cell Wall Polysaccharide ◽  
Acidic Water ◽  
Soluble Cell ◽  
Chemotaxonomic Marker

scholarly journals Near-Infrared Studies of Glucose and Sucrose in Aqueous Solutions: Water Displacement Effect and Red Shift in Water Absorption from Water-Solute Interaction

2013 ◽  
Vol 67 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Youngeui Jung ◽  
Jungseek Hwang
Keyword(s):  
Aqueous Solutions ◽  
Near Infrared ◽  
Hydration Shell ◽  
Glucose Absorption ◽  
Water Soluble ◽  
Red Shift ◽  
Water Molecules ◽  
Water Displacement ◽  
Absorption Bands ◽  
Displacement Effect

We used near infrared spectroscopy to obtain concentration dependent glucose absorption spectra in aqueous solutions in the near-infrared range (3800–7500 cm−1). Here we introduce a new method to obtain reliable glucose absorption bands from aqueous glucose solutions without measuring the water displacement coefficients of glucose separately. Additionally, we were able to extract the water displacement coefficients of glucose, and this may offer a new general method using spectroscopy techniques applicable to other water-soluble materials. We also observed red shifts in the absorption bands of water in the hydration shell around solute molecules, which comes from the contribution of the interacting water molecules around the glucose molecules in solutions. The intensity of the red shift gets larger as the concentration increases, which indicates that as the concentration increases more water molecules are involved in the interaction. However, the red shift in frequency does not seem to depend significantly on the concentration. We also performed the same measurements and analysis with sucrose instead of glucose as solute and compared.

scholarly journals On the relative absorption strengths of water vapour in the blue wavelength range

2015 ◽  
Vol 8 (6) ◽  
pp. 5895-5936 ◽  
Author(s):  
J. Lampel ◽  
D. Pöhler ◽  
J. Tschritter ◽  
U. Frieß ◽  
U. Platt
Keyword(s):  
Water Vapour ◽  
Cross Sections ◽  
Spectral Region ◽  
Field Measurements ◽  
Optical Absorption Spectroscopy ◽  
Absorption Cross ◽  
Absorption Bands ◽  
Blue Wavelength ◽  
Water Vapour Absorption ◽  
Density Ratios

Abstract. In recent updates of the HITRAN water vapour H2O spectroscopic compilation covering the blue spectral region (here: 394–480 nm) significant changes for the absorption bands at 416 and 426 nm were reported. In order to investigate the consistency of the different cross-sections calculated from these compilations, H2O vapour column density ratios for different spectral intervals were retrieved from Long-path and Multi-Axis – Differential Optical Absorption Spectroscopy (DOAS) measurements. We observed a significant improvement of the DOAS evaluation when using the updated HITRAN water vapour absorption cross-sections for the calculation of the reference spectra. In particular the magnitudes of the residual spectra as well as the fit errors were reduced. However we also found that the best match between measurement and model is reached when the absorption cross-section of groups of lines are scaled by factors ranging from 0.5 and 1.9, suggesting that the HITRAN water vapour absorption compilation still needs significant corrections. For this spectral region we present correction factors for HITRAN 2009, HITRAN 2012, HITEMP and BT2 derived from field measurements. Additionally, upper limits for water vapour absorption in the UV-A range from 330–390 nm are given.

scholarly journals SULFATION OF ABIES ETHANOL LIGNIN WITH COMPLEXES OF SULFUR TRIOXIDE WITH 1,4-DIOXANE AND PYRIDINE

2020 ◽  
pp. 5-15
Author(s):  
Yuriy Nikolayevich Malyar ◽  
Natal'ya Yur'yevna Vasil'yeva ◽  
Aleksandr Sergeyevich Kazachenko ◽  
Galina Pavlovna Skvortsova ◽  
Irina Vladimirovna Korol'kova ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Sulfur Trioxide ◽  
Chlorosulfonic Acid ◽  
Gel Permeation Chromatography ◽  
Ftir Spectra ◽  
Water Soluble ◽  
Simultaneous Increase ◽  
Absorption Bands ◽  
High Sulfur Content ◽  
Low Degree

In this work, we optimized the process of sulfating abies ethanol lignin with complexes of sulfuric anhydride with pyridine and 1,4-dioxane. Experimentally found are the conditions for the implementation of the process of sulfation of abies ethanol lignin by complexes of sulfur trioxide with 1,4-dioxane and pyridine, providing a high sulfur content (12.0–12.6%). It was shown that a high sulfur content of 12.0–13.5% (mass.) in the obtained ethanol lignin sulfate is achieved when the ratio of the amount of chlorosulfonic acid to the amount of abies ethanol lignin is 20.22 : 1 mmol : g and the duration of the sulfation process is 60–120 min and independent of the nature of the sulfating complex. The structure and composition of water-soluble sulfated abies ethanol lignin are confirmed by FTIR spectroscopy, gel permeation chromatography and elemental analysis. In the FTIR spectra of sulfated abies ethanol lignin, in comparison with the FTIR spectra of the initial abies ethanol lignin, there are absorption bands in the region of 1270–1260, 1220–1212, 861–803 cm-1, corresponding to vibrations of sulfate groups. Compared to the initial lignin, sulfated abies ethanol lignin has a low degree of polydispersity. In particular, there was an increase in Mw c ~1.5 kDa to ~3.4 kDa in lignin sulfated for 30 min and a decrease in polydispersity from 2.59 to 1.22 compared to the initial abies ethanol lignin. With an increase in the sulfation time, the profile of the molecular mass distribution curve shifts to a high molecular weight region, with a simultaneous increase in polydispersity to 1.5 and Mw increases to ~4.3 kDa.

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