scholarly journals Hydroporphyrins of the meso-tetra(hydroxyphenyl)porphyrin series as tumour photosensitizers

1989 ◽  
Vol 261 (1) ◽  
pp. 277-280 ◽  
Author(s):  
R Bonnett ◽  
R D White ◽  
U J Winfield ◽  
M C Berenbaum
Keyword(s):  
Visible Spectrum ◽  
Strong Absorption ◽  
Absorption Bands

Four new hydroporphyrins [the o, m and p isomers of 5,10,15,20-tetra(hydroxyphenyl)chlorin and 5,10,15,20-tetra(m-hydroxyphenyl)bacteriochlorin] related to the tetra(hydroxyphenyl)porphyrins have been prepared. They show the expected strong absorption bands in the red region of the visible spectrum and are found to be very effective tumour photosensitizers.

Peroxidase: a multifunctional enzyme in grapevines

2003 ◽  
Vol 30 (6) ◽  
pp. 577 ◽  
Author(s):  
Alfonso Ros Barceló ◽  
Federico Pomar ◽  
Matías López-Serrano ◽  
Maria Angeles Pedreño
Keyword(s):  
Cell Wall ◽  
Metabolic Regulation ◽  
Trichoderma Viride ◽  
Visible Spectrum ◽  
H2o2 Production ◽  
Class Iii ◽  
Absorption Bands ◽  
Peroxidase Isoenzyme ◽  
Wide Range ◽  
Uv C

Peroxidases are heme-containing enzymes that catalyse the one-electron oxidation of several substrates at the expense of H2O2. They are probably encoded by a large multigene family in grapevines, and therefore show a high degree of polymorphism. Grapevine peroxidases are glycoproteins of high thermal stability, whose molecular weight usually ranges from 35 to 45 kDa. Their visible spectrum shows absorption bands characteristic of high-spin class III peroxidases. Grapevine peroxidases are capable of accepting a wide range of natural compounds as substrates, such as the cell wall protein extensin, plant growth regulators such as IAA, and phenolics such as benzoic acids, stilbenes, flavonols, cinnamyl alcohols and anthocyanins. They are located in cell walls and vacuoles. These locations are in accordance with their key role in determining the final cell wall architecture, especially regarding lignin deposition and extensin insolubilization, and the turnover of vacuolar phenolic metabolites, a task that also forms part of the molecular program of disease resistance. Although peroxidase is a constitutive enzyme in grapevines, its levels are strongly modulated during plant cell development and in response to both biotic and abiotic environmental factors. To gain an insight into the metabolic regulation of peroxidase, several authors have studied how grapevine peroxidase and H2O2 levels change in response to a changing environment. Nevertheless, the results obtained are not always easy to interpret. Despite such difficulties, the response of the peroxidase–H2O2 system to both UV-C radiation and Trichoderma viride elicitors is worthy of study. Both UV-C and T. viride elicitors induce specific changes in peroxidase isoenzyme / H2O2 levels, which result in specific changes in grapevine physiology and metabolism. In the case of T. viride-elicited grapevine cells, they show a particular mechanism for H2O2 production, in which NADPH oxidase-like activities are apparently not involved. However, they offer a unique system whereby the metabolic regulation of peroxidase by H2O2, with all its cross-talks and downstream signals, may be elegantly dissected.

A built-in zero valent iron anaerobic reactor to enhance treatment of azo dye wastewater

2011 ◽  
Vol 63 (4) ◽  
pp. 741-746 ◽  
Author(s):  
Yaobin Zhang ◽  
Yanwen Jing ◽  
Xie Quan ◽  
Yiwen Liu ◽  
Pascal Onu
Keyword(s):  
Azo Dye ◽  
Visible Spectrum ◽  
Zero Valent Iron ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Dye Wastewater ◽  
Absorption Bands ◽  
Anaerobic Reactor ◽  
Anaerobic Sludge Blanket

Waste scrap iron was packed into an upflow anaerobic sludge blanket (UASB) reactor to form a zero valent iron (ZVI) - UASB reactor system for treatment of azo dye wastewater. The ZVI acted as a reductant to decrease ORP in the reactor by more than 40 mv and functioned as an acid buffer to increase the pH in the reactor from 5.44 to 6.29, both of which improved the performance of the anaerobic reactor. As a result, the removal of color and COD in this reactor was 91.7% and 53%, respectively, which was significantly higher than that of a reference UASB reactor without ZVI. The UV-visible spectrum demonstrated that absorption bands of the azo dye from the ZVI-UASB reactor were substantially reduced. The ZVI promoted methanogenesis, which was confirmed by an increase in CH4 content in the biogas from 47.9% to 64.8%. The ZVI bed was protected well from rusting, which allowed it to function stably. The effluent could be further purified only by pH adjustment because the Fe2+ released from ZVI served as a flocculent.

scholarly journals Detection limits of organic compounds achievable with intense, short-pulse lasers

The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 4270-4276 ◽  
Author(s):  
Jordan Miles ◽  
Simone De Camillis ◽  
Grace Alexander ◽  
Kathryn Hamilton ◽  
Thomas J. Kelly ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Organic Molecules ◽  
Short Pulse ◽  
Detection Limits ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Short Pulse Lasers

Many organic molecules have strong absorption bands which can be accessed by ultraviolet short pulse lasers to produce efficient ionization.

Fourier-transform photoacoustic spectroscopy: a more complete method for quantitative analysis

1986 ◽  
Vol 64 (9) ◽  
pp. 1081-1085 ◽  
Author(s):  
M. Choquet ◽  
G. Rousset ◽  
L. Bertrand
Keyword(s):  
Absorption Spectrum ◽  
Fourier Transform ◽  
Quantitative Analysis ◽  
Photoacoustic Spectroscopy ◽  
Photoacoustic Signal ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Asbestos Fibers ◽  
Fourier Transform Spectra ◽  
Signal Saturation

Strong absorption bands of photoacoustic Fourier-transform spectra are often truncated relative to weaker bands owing to signal saturation. To correct this problem, we propose processing both the phase and the amplitude information in the photoacoustic signal. Under certain conditions, easily fulfilled in typical experiments, we are able to calculate the absolute absorption spectrum from the photoacoustic data. Experimental results are given for asbestos fibers (chrysotile).

scholarly journals The absorption spectra of conjugated dienes in the vacuum ultra-violet (1)

1940 ◽  
Vol 174 (957) ◽  
pp. 220-234 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Ultra Violet ◽  
Conjugated Dienes ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Lennard Jones ◽  
Vacuum Ultra Violet

Butadiene is important as the simplest example of resonance between two conjugated double bonds. The comparison of its ultra-violet absorption spectrum with that of ethylene might be expected to give some indication of the way the π electrons of the molecule are affected by the resonance. The electronic structures of a number of molecules for which resonance is important have been worked out theoretically by Hückel (1935), Lennard- Jones (1937), Sklar (1937) and Mulliken (1939 a and b ). The purpose of the present work is to obtain spectroscopic data with which the theoretical expectations can be compared. As most of the strong absorption bands of these molecules occur at wave-lengths less than 2000 A, the investigation falls naturally into the region of vacuum spectroscopy.

Structure, stability and spectral properties of seleno[n]helicenes (n = 1–10)

2020 ◽  
Vol 44 (2) ◽  
pp. 428-441
Author(s):  
Rahul Kumar ◽  
Dilip Kumar Maity
Keyword(s):  
Excited State ◽  
Spectral Properties ◽  
Radical Cations ◽  
Strong Absorption ◽  
Structure Stability ◽  
Absorption Bands ◽  
Stable Structures

The most stable structures of seleno[n]helicenes (n = 3–10) are flexible and helical in nature. The excited state results show that many of the seleno[n]helicene radical cations have strong absorption bands in the IR region.

scholarly journals The Evolution of Hα Profiles in S-type Mira Stars

1993 ◽  
Vol 139 ◽  
pp. 209-209
Author(s):  
A.W. Woodsworth
Keyword(s):  
Shock Waves ◽  
Data Base ◽  
Strong Absorption ◽  
Emission Lines ◽  
High Dispersion ◽  
Absorption Bands ◽  
Good Data ◽  
Mira Variables ◽  
Static Models ◽  
Simple Models

Past attempts to model the Hα emission profiles from Mira stars have been hampered by the strong absorption bands produced by TiO (M-type Miras) or carbon-based molecules (C-type Miras). The S-type Miras, however, exhibit relatively clean emission lines. As part of a larger study of Mira variables, I have obtained a series of high-dispersion Hα profiles of S-type Miras at different phases, using the DAO 48” coudé spectrograph. Although most profiles were obtained from different stars, their shapes develop in a regular way with advancing phase, so it appears that the observations can be used together to provide a good data base for the fitting of evolutionary (rather than static) models for the shock waves in S-type Miras.Initial experiments with fitting simple models to the profiles have been extremely encouraging. The profiles can be represented very well by three Gaussian components.

scholarly journals The absorption spectra of solutions of cobalt chloride, cobalt bromide, and cobalt iodide in concentrated hydrochloric, hydrobromic, and hydriodic acids

1928 ◽  
Vol 120 (784) ◽  
pp. 21-33 ◽  
Keyword(s):  
Cobalt Chloride ◽  
Wave Length ◽  
Radiant Energy ◽  
Visible Spectrum ◽  
Hydriodic Acid ◽  
Selective Absorption ◽  
Absorption Bands ◽  
Average Deviation ◽  
The Mean ◽  
Absorption Measurements

In a recent paper by one of us (W. R. B) the selective absorption in the region of 600 to 710 mμ of cobalt chloride dissolved in concentrated hydrochloric acid was shown to consist of a number of superimposed, similarly shaped absorption bands. The frequency values at which these component bands exhibited a maximum of absorption corresponded with integral multiples of a common of fundamental frequency. The analysis of the observed absorption curve has now been extended into the blue so as to cover the whole of the selective absorption occurring in the visible portion of the spectrum. Similar analyses have also been obtained for the absorption shown by cobalt bromide when dissolved in concentrated hydrobromic acid and cobalt iodide dissolved in concentrated hydriodic acid. Apparatus and Method of Observation . The apparatus previously described was again used. Since the principal absorption band of cobalt bromide, as compared with that of cobalt chloride, is situated farther towards the red end of the visible spectrum, where the dispersion of the apparatus is smaller, the wave-length interval between the different sets of observations was increased from 2 to 2·5 mμ in the region of 625 to 725 mμ . At every wave-length value for which absorption measurements were obtained on the principal band, a minimum of 20 observations were made, and in the extreme red, where the sensitivity of the eye is poor, the number of observations was even larger. The average deviation from the mean absorption value E (where E = log 10 I 0 /I, I 0 being the intensity of the radiant energy passing through the comparison cell filled with the solvent, and I the intensity of the radiant energy passing through the cell containing the solvent and the material under observations) was approximately the same as in the earlier work on cobalt chloride, i. e. , 0·025.

scholarly journals PHOTOSENSITIZATION OF ANIMALS AFTER THE INGESTION OF BUCKWHEAT

1928 ◽  
Vol 47 (6) ◽  
pp. 1013-1028 ◽  
Author(s):  
Charles Sheard ◽  
Harold D. Caylor ◽  
Carl Schlotthauer
Keyword(s):  
Wave Length ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Mercury Vapor ◽  
Malignant Neoplasms ◽  
Absorption Bands ◽  
Quartz Mercury ◽  
Degree Of Sensitization ◽  
The Common ◽  
Mercury Vapor Lamp

The chief points presented in this paper are: 1. Following the ingestion of buckwheat (plant or seed) varicolored guinea pigs, white swine and goats exhibited symptoms of photosensitization, the degree of sensitization being in the order given. 2. Rabbits, dogs, white mice and rats did not manifest symptoms of photosensitization. 3. The symptoms and reactions were: agitation, itching, scratching of the ears, weakness, urticaria with sloughing and symptoms similar to those in anaphylaxis. 4. Microscopic examinations showed the lack of marked pathologic change. The lesions, such as petechial hemorrhage of the lungs, brain, liver, stomach and kidneys, suggest that profound toxemia has been present. 5. Lesions were not found which appeared to be suggestive of malignant neoplasms. 6. Irradiation by a quartz mercury vapor lamp apparently develops a resistance to photosensitization, probably because of increased pigmentation induced by ultra-violet light. 7. From the nature of the physiologic and pathologic reactions produced under various filters and from a consideration of the percentages of transmission of solar energy in the visible spectrum, it would seem that the region of photosensitization lies between 580 millimicrons (yellow) and the red end of the spectrum. This conclusion, moreover, is substantiated by the fact that irradiation by a quartz mercury vapor lamp (which radiates no energy in the visible spectrum at a wave-length greater than 579 millimicrons) produces no symptoms or reactions. 8. Spectrophotometric determinations of alcoholic extracts of grass (non-toxic) and of buckwheat (toxic) show the presence of two additional bands in the absorption spectrum of buckwheat with maxima at about 540 and 600 millimicrons, respectively, together with the common absorption zones at 430 to 490 millimicrons and 630 to 690 millimicrons. 9. Spectrophotometric determinations of blood serums of sensitized animals show, besides the usual absorption bands peculiar to oxyhemoglobin (with maxima at 540 and 580 millimicrons respectively), two zones with maxima at 600 and 660 millimicrons respectively. 10. The fluorescence of chlorophyll per se, as suggested by previous investigators, is not, in all probability, the cause of the sensitization induced by buckwheat. 11. Hematoporphyrine is not the photodynamic substance in all probability. 12. Phylloporphyrine may be the photodynamic substance. In this regard, also, the possibility of cholehematin is not to be ruled out.

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