The Raman Spectrum of Rubber

1935 ◽  
Vol 8 (4) ◽  
pp. 521-521
Author(s):  
S. D. Gehman
Keyword(s):  
Raman Effect ◽  
Monochromatic Light ◽  
Ultra Violet ◽  
Light Filter ◽  
Oxidation Products ◽  
Colloidal Structure ◽  
Light Filters ◽  
Wide Range ◽  
Continuous Background ◽  
Viscous Solutions

Abstract It has been previously reported that the Raman effect is exhibited by rubber as a continuous scattering together with the presence of broad bands (Franklin and Laird, Phys. Rev., 36, 147 (1930); Busse, J. Phys. Chem., 36, 2862 (1932)). Busse attributed this result to the viscosity of the solutions or to the possibility that the rubber groups respond to a wide range of frequencies. However, viscous solutions of polysterol in carbon tetrachloride give a line spectrum (Signer and Weiler, Helv. Chim. Acta, 15, 649 (1932)). As to the second explanation, this does not seem to be the nature of the Raman effect (Bär, Helv. Phys. Acta, 4, 369 (1931); Bär, Z. Physik, 79, 455 (1932)). The Raman effect has been investigated extensively for terpenes other than rubber. The bands and continuous background for rubber appear to be due to fluorescence of impurities, oxidation products, or the rubber hydrocarbon. The acetone extract of rubber is fluorescent as observed in ultra-violet light. The intensity of the bands and background for rubber decreases as the rubber is purified. However, acetone extraction and two diffusions with ethyl ether did not remove the fluorescence entirely, as could be seen by examination between complementary light filters. Some of the background is undoubtedly unmodified radiation, that is, Tyndall scattering by the colloidal structure and by motes. This can be reduced by a monochromatic light filter.

scholarly journals Study of electrolytic dissociation by the Raman effect. I.—Nitric acid

1930 ◽  
Vol 127 (805) ◽  
pp. 279-289 ◽  
Keyword(s):  
Nitric Acid ◽  
Raman Effect ◽  
Scattered Light ◽  
Monochromatic Light ◽  
Ultra Violet ◽  
Spectral Lines ◽  
Electrolytic Dissociation ◽  
Infra Red ◽  
The Difference

In a recent discovery Raman found that when monochromatic light of frequency v is incident upon a substance, the scattered light contains not only light of the original frequency v hut also light of modified frequency v 1 , and the difference in frequency between the two corresponds to an infra-red character­istic frequency v 0 of the molecules constituting the substance. Thus a new field of work has been opened up, in which the infra-red characteristic frequencies of molecules can be determined with as much precision as is possible in the visible and ultra-violet regions of the spectrum. The present investigation has shown a further possibility of the new discovery. On studying the Raman effect in solutions of nitric acid at different concentrations, the author was able to trace the progress in the electrolytic dissociation of the acid by measuring the changes in the intensities of the Raman lines due to the undissociated molecules and of the ions. Thus the method not only gives direct evidence of the phenomenon of dissociation, but enables the determination of its amount as accurately as is possible in the measurement of intensities of spectral lines. The only defect of the method lies in the fact that it cannot be extended to those electrolytes that do not show any Raman lines. The purpose of the present communication is to describe the results with nitric acid.

scholarly journals A coma-free super-high resolution optical spectrometer using 44 high dispersion sub-gratings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hua-Tian Tu ◽  
An-Qing Jiang ◽  
Jian-Ke Chen ◽  
Wei-Jie Lu ◽  
Kai-Yan Zang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Wavelength Region ◽  
Ultra Violet ◽  
High Spectral Resolution ◽  
Visible Range ◽  
High Dispersion ◽  
Charge Coupled Device ◽  
Wide Range ◽  
High Resolution Spectrometer

AbstractUnlike the single grating Czerny–Turner configuration spectrometers, a super-high spectral resolution optical spectrometer with zero coma aberration is first experimentally demonstrated by using a compound integrated diffraction grating module consisting of 44 high dispersion sub-gratings and a two-dimensional backside-illuminated charge-coupled device array photodetector. The demonstrated super-high resolution spectrometer gives 0.005 nm (5 pm) spectral resolution in ultra-violet range and 0.01 nm spectral resolution in the visible range, as well as a uniform efficiency of diffraction in a broad 200 nm to 1000 nm wavelength region. Our new zero-off-axis spectrometer configuration has the unique merit that enables it to be used for a wide range of spectral sensing and measurement applications.

scholarly journals Extensive reduction of surface UV radiation since 1750 in world's populated regions

2009 ◽  
Vol 9 (20) ◽  
pp. 7737-7751 ◽  
Author(s):  
M. M. Kvalevåg ◽  
G. Myhre ◽  
C. E. Lund Myhre
Keyword(s):  
Uv Radiation ◽  
Correlation Coefficients ◽  
Ultra Violet ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Polar Regions ◽  
Ultra Violet Radiation ◽  
Wide Range ◽  
Extensive Surface ◽  
Year 2000

Abstract. Human activity influences a wide range of components that affect the surface UV radiation levels, among them ozone at high latitudes. We calculate the effect of human-induced changes in the surface erythemally weighted ultra-violet radiation (UV-E) since 1750. We compare results from a radiative transfer model to surface UV-E radiation for year 2000 derived by satellite observations (from Total Ozone Mapping Spectroradiometer) and to ground based measurements at 14 sites. The model correlates well with the observations; the correlation coefficients are 0.97 and 0.98 for satellite and ground based measurements, respectively. In addition to the effect of changes in ozone, we also investigate the effect of changes in SO2, NO2, the direct and indirect effects of aerosols, albedo changes and aviation-induced contrails and cirrus. The results show an increase of surface UV-E in polar regions, most strongly in the Southern Hemisphere. Furthermore, our study also shows an extensive surface UV-E reduction over most land areas; a reduction up to 20% since 1750 is found in some industrialized regions. This reduction in UV-E over the industrial period is particularly large in highly populated regions.

Chemical Stability of Proteins in Foods: Oxidation and the Maillard Reaction

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Mahesha M. Poojary ◽  
Marianne N. Lund
Keyword(s):  
Maillard Reaction ◽  
Protein Oxidation ◽  
Oxidation Products ◽  
Protein Carbonyls ◽  
Annual Review ◽  
Publication Date ◽  
Food Protein ◽  
Food Proteins ◽  
Wide Range ◽  
Specific Oxidation

Protein is a major nutrient present in foods along with carbohydrates and lipids. Food proteins undergo a wide range of modifications during food production, processing, and storage. In this review, we discuss two major reactions, oxidation and the Maillard reaction, involved in chemical modifications of food proteins. Protein oxidation in foods is initiated by metal-, enzyme-, or light-induced processes. Food protein oxidation results in the loss of thiol groups and the formation of protein carbonyls and specific oxidation products of cysteine, tyrosine, tryptophan, phenylalanine, and methionine residues, such as disulfides, dityrosine, kynurenine, m-tyrosine, and methionine sulfoxide. The Maillard reaction involves the reaction of nucleophilic amino acid residues with reducing sugars, which yields numerous heterogeneous compounds such as α-dicarbonyls, furans, Strecker aldehydes, advanced glycation end-products, and melanoidins. Both protein oxidation and the Maillard reaction result in the loss of essential amino acids but may positively or negatively impact food structure and flavor. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Abstract P461: Genome-wide Analysis in Sedentary Adults of Non-completion of a Controlled Exercise Intervention

Circulation ◽  
2020 ◽  
Vol 141 (Suppl_1) ◽  
Author(s):  
Rong Jiang ◽  
Kim M Huffman ◽  
Elizabeth Hauser ◽  
Monica Hubal ◽  
Cris Slentz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Exercise Intervention ◽  
Linkage Disequilibrium Block ◽  
Exercise Program ◽  
Oxidation Products ◽  
Expression Array ◽  
Genetic Traits ◽  
Wide Range ◽  
Risk Reduction Intervention

A wide range of health benefits of exercise have been documented in clinical lifestyle medicine. However, many individuals fail to complete or maintain an exercise program. We hypothesized that this behavior has biological underpinnings. Thus, we conducted analyses of multi-omic data obtained from genomic, transcriptomic and metabolomic data specific to subjects (n=603) initiating a well-characterized exercise training trial (STRRIDE-Study of a Targeted Risk Reduction Intervention through Defined Exercise) to understand the biology of non-completion. GWAS detected the strongest evidence of association with non-completion was at SNP rs722069 (P = 2.2 х 10 -7 , OR=2.23, T/C, risk allele =C) on chromosome 16, with other 8 SNPs in a linkage disequilibrium block (pairwise R 2 > 0.74). These SNPs were eQTLs of the EARS2, COG7 and DCTN5 genes in skeletal muscle tissue in GTEx portal. In a subset of the STRRIDE sample, the C allele of rs722069 was associated with lower pre-exercise skeletal muscle expression of EARS2 (P < 0.016) using Affymetrix platform (n=37). This was further replicated (P=0.017) in another set of skeletal muscle expression data using the Illumina gene expression array (n=67). The C allele was associated with lower pre-exercise skeletal muscle concentrations of C2- and C3-acylcarnitines (P < 0.03) - the incomplete oxidation products of fatty acid and amino acid metabolism. Lower EARS2 skeletal muscle expression was also related to the lower C2- and C3-acylcarnitine concentrations in skeletal muscle ( P < 0.05) before exercise. Rs722069 variants were not related to maximal oxygen uptake and insulin sensitivity in the individuals completing the exercise intervention. The tests of glucose and lipids levels associated with the genetic variants in this LD block are ongoing. To further understand the systemic genetics and biology of non-completion, in silico functional analysis for the genes in this region such as UBFD1, NDUFAB1, PALB2 is also under way. Our results imply that non-completion is genetically moderated through differential gene expression and metabolic pathways in skeletal muscle. Impaired mitochondrial energetics in skeletal muscle may be partly responsible for non-completion. Individual genetic traits may allow development of a biomarker-approach to identify individuals that would benefit from more intensive counseling to maintain exercise programs.

scholarly journals Enzyme Specificity of 2-Nitrotoluene 2,3-Dioxygenase from Pseudomonas sp. Strain JS42 Is Determined by the C-Terminal Region of the α Subunit of the Oxygenase Component

1998 ◽  
Vol 180 (5) ◽  
pp. 1194-1199 ◽  
Author(s):  
Juanito V. Parales ◽  
Rebecca E. Parales ◽  
Sol M. Resnick ◽  
David T. Gibson
Keyword(s):  
Amino Acid Sequence Identity ◽  
Large Subunit ◽  
Small Subunit ◽  
Terminal Region ◽  
Oxidation Products ◽  
Enzyme Specificity ◽  
Α Subunit ◽  
Sequence Identity ◽  
Wide Range ◽  
Genes Encoding

ABSTRACT Biotransformations with recombinant Escherichia coliexpressing the genes encoding 2-nitrotoluene 2,3-dioxygenase (2NTDO) from Pseudomonas sp. strain JS42 demonstrated that 2NTDO catalyzes the dihydroxylation and/or monohydroxylation of a wide range of aromatic compounds. Extremely high nucleotide and deduced amino acid sequence identity exists between the components from 2NTDO and the corresponding components from 2,4-dinitrotoluene dioxygenase (2,4-DNTDO) from Burkholderia sp. strain DNT (formerlyPseudomonas sp. strain DNT). However, comparisons of the substrates oxidized by these dioxygenases show that they differ in substrate specificity, regiospecificity, and the enantiomeric composition of their oxidation products. Hybrid dioxygenases were constructed with the genes encoding 2NTDO and 2,4-DNTDO. Biotransformation experiments with these hybrid dioxygenases showed that the C-terminal region of the large subunit of the oxygenase component (ISPα) was responsible for the enzyme specificity differences observed between 2NTDO and 2,4-DNTDO. The small subunit of the terminal oxygenase component (ISPβ) was shown to play no role in determining the specificities of these dioxygenases.

scholarly journals Ultra-Violet Absorption and Raman Effect for Hydrazine

Nature ◽  
1931 ◽  
Vol 127 (3212) ◽  
pp. 782-782 ◽  
Author(s):  
S. IMANISHI
Keyword(s):  
Raman Effect ◽  
Ultra Violet

scholarly journals Terpenes and their oxidation products in the French Landes forest: insights from Vocus PTR-TOF measurements

2020 ◽  
Vol 20 (4) ◽  
pp. 1941-1959 ◽  
Author(s):  
Haiyan Li ◽  
Matthieu Riva ◽  
Pekka Rantala ◽  
Liine Heikkinen ◽  
Kaspar Daellenbach ◽  
...  
Keyword(s):  
Gas Phase ◽  
Detection Efficiency ◽  
Ambient Air ◽  
Reaction Rates ◽  
Early Morning ◽  
Oxidation Products ◽  
Atmospheric Oxidation ◽  
Organic Nitrates ◽  
Reaction Products ◽  
Wide Range

Abstract. The capabilities of the recently developed Vocus proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF) are reported for the first time based on ambient measurements. With the deployment of the Vocus PTR-TOF, we present an overview of the observed gas-phase (oxygenated) molecules in the French Landes forest during summertime 2018 and gain insights into the atmospheric oxidation of terpenes, which are emitted in large quantities in the atmosphere and play important roles in secondary organic aerosol production. Due to the greatly improved detection efficiency compared to conventional PTR instruments, the Vocus PTR-TOF identifies a large number of gas-phase signals with elemental composition categories including CH, CHO, CHN, CHS, CHON, CHOS, and others. Multiple hydrocarbons are detected, with carbon numbers up to 20. Particularly, we report the first direct observations of low-volatility diterpenes in the ambient air. The diurnal cycle of diterpenes is similar to that of monoterpenes and sesquiterpenes but contrary to that of isoprene. Various types of terpene reaction products and intermediates are also characterized. Generally, the more oxidized products from terpene oxidations show a broad peak in the day due to the strong photochemical effects, while the less oxygenated products peak in the early morning and/or in the evening. To evaluate the importance of different formation pathways in terpene chemistry, the reaction rates of terpenes with main oxidants (i.e., hydroxyl radical, OH; ozone, O3; and nitrate radical, NO3) are calculated. For the less oxidized non-nitrate monoterpene oxidation products, their morning and evening peaks have contributions from both O3- and OH-initiated monoterpene oxidation. For the monoterpene-derived organic nitrates, oxidations by O3, OH, and NO3 radicals all contribute to their formation, with their relative roles varying considerably over the course of the day. Through a detailed analysis of terpene chemistry, this study demonstrates the capability of the Vocus PTR-TOF in the detection of a wide range of oxidized reaction products in ambient and remote conditions, which highlights its importance in investigating atmospheric oxidation processes.

Raman Effect in the Ultra-violet Region

1931 ◽  
Vol 35 (6) ◽  
pp. 1735-1744 ◽  
Author(s):  
J. C. Ghosh ◽  
B. C. Kar
Keyword(s):  
Raman Effect ◽  
Ultra Violet

scholarly journals Changes in the Raman spectrum of sulphuric acid on dilution

1934 ◽  
Vol 144 (851) ◽  
pp. 129-143 ◽  
Keyword(s):  
Sulphuric Acid ◽  
Raman Effect ◽  
Wave Length ◽  
Frequency Shifts ◽  
Low Concentrations ◽  
Intensity Changes ◽  
Continuous Background ◽  
Length Determination ◽  
Detailed Interpretation ◽  
Two Stages

The results of previous workers upon the Raman effect of sulphuric acid show a considerable lack of agreement, due no doubt in part to the intensity of the accompanying continuous background and the apparent diffuseness of certain of the lines. Thus both Nisi and Woodward found that change of the concentration of the add greatly modified the appearance of the spectrum, influencing both the positions and the relative intensities of the lines. Wood-ward gave photometer carves of the spectra for concentrations ranging from 100% to 25% by volume, and attributed the observed intensity changes to tho successive stages of ionization of the acid. The lines Δ v = 910 and 1140 cm. -1 (approximate values), which were strong in the 100% acid, became weaker and shifted somewhat as the concentration decreased; while a new line Δ v = 1046 cm. -1 made its appearance and increased correspondingly in intensity. At low concentrations this last line became double, a companion appearing at 982 cm. -1 . The frequencies 910 and 1110 were regarded as characteristic of the H 2 SO 4 molecule, 1016 of the HSO' 4 ion, and 982 of the SO" 4 ion. Other diffuse lines also showed frequency shifts. Bell and Fredrickson. however, whose measurements were made not only with a prism spectrograph but also with a grating, failed to find any appreciable shifts of the line with dilution. Moreover, they stated that on their plates the 1016 line gave no indication of becoming double at low concentrations, but merely grew more diffuse. The findings of other workers are referred to in the discussion of our results (see below). In view of the conflicting nature of the above evidence regarding the two stages of ionisation of the acid, it was thought, desirable to repeat tho investigations using a higher dispersion than that employed by Woodward ( loc. cit .), the object of the work being to obtain more conclusive photometer curves of the spectra. The curves we have actually obtained not only give a clear picture of the intensity changes involved, but have also been used in a rational method of wave-length determination, the adoption of which has made it possible for us to propose a somewhat more detailed interpretation of the spectra than has hitherto been attempted.

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