scholarly journals pH induced changes in Raman, UV-Vis absorbance, and fluorescence spectra of dipicolinic acid (DPA)

2022 ◽  
pp. 120869
Author(s):  
Dmitry Malyshev ◽  
Rasmus Öberg ◽  
Lars Landström ◽  
Per Ola Andersson ◽  
Tobias Dahlberg ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Dipicolinic Acid ◽  
Induced Changes

A test of the role of refractive index in correlations between solvent effects on electronic spectra and solvent effects on reaction equilibria and rates

1984 ◽  
Vol 49 (10) ◽  
pp. 2332-2341 ◽  
Author(s):  
Vojtěch Bekárek
Keyword(s):  
Refractive Index ◽  
Solvent Effects ◽  
Electronic Spectra ◽  
Kinetic Data ◽  
Fluorescence Spectra ◽  
Simple Relation ◽  
Absorption And Fluorescence Spectra ◽  
Induced Changes ◽  
Better Than

80 correlations have been carried out between the medium-induced changes in equilibrium and kinetic data (Y) and the medium-induced changes in positions of maxima in electronic (both absorption and fluorescence) spectra (Δν) of the Kamlet-Taft type indicators. The correlations have been carried out by means of the equations Y=Y0 + k . Δν and Y=Y0 + k' . Δν/f(n2) using only the Kamlet-Taft select solvents (SSS). The equation involving the function of refreactive index (n), f(n2) = (n2 - 1)/(2n2 + 1), is better than the simple relation between Y and Δν in 93% of the systems studied. The problem of HBD acidity of nitromethane and the relation of the A and B solvent characteristics by Swain and the characteristics of dipolarity of medium by Kamlet-Taft are discussed.

Two Dimensional Multiwavelength Fluorescence Spectra of Dipicolinic Acid and Calcium Dipicolinate

2004 ◽  
Author(s):  
Sivananthan Sarasanandarajah ◽  
Joseph Kunnil ◽  
Burt V. Bronk ◽  
Lou Reinisch ◽  
Burt V. Bronk
Keyword(s):  
Fluorescence Spectra ◽  
Dipicolinic Acid ◽  
Two Dimensional

Albumin-Induced Changes of Fluorescence Spectra of 1-Pyrenebutyric Acid

1986 ◽  
Vol 75 (2) ◽  
pp. 193-194 ◽  
Author(s):  
Yasuo Matsushita ◽  
Mariko Tsukiori ◽  
Tatsuo Suzuki ◽  
Ikuo Moriguchi
Keyword(s):  
Fluorescence Spectra ◽  
Induced Changes

Two-dimensional multiwavelength fluorescence spectra of dipicolinic acid and calcium dipicolinate

2005 ◽  
Vol 44 (7) ◽  
pp. 1182 ◽  
Author(s):  
Sivananthan Sarasanandarajah ◽  
Joseph Kunnil ◽  
Burt V. Bronk ◽  
Lou Reinisch
Keyword(s):  
Fluorescence Spectra ◽  
Dipicolinic Acid ◽  
Two Dimensional

Wear-Induced Changes in the Raman, Infrared, and Fluorescence Spectra of Silicon Nitride Surfaces

1996 ◽  
Vol 50 (11) ◽  
pp. 1378-1388 ◽  
Author(s):  
James L. Lauer
Keyword(s):  
Silicon Nitride ◽  
Fluorescence Spectra ◽  
Wear Track ◽  
Laser Excitation ◽  
Energy Gap ◽  
Silicon Oxycarbide ◽  
Ion Laser ◽  
Argon Stream ◽  
Induced Changes ◽  
Argon Ion

Commercial α-silicon nitride plates and balls used in simulated sliding bearing tests were found to fluoresce under 514.5-nm argon-ion laser excitation after heating to above 350 °C in a stream of argon. Wear track areas fluoresced much more intensely than their surroundings. When small concentrations of ethylene or other carbonaceous gas were added to the argon stream, carbonaceous deposits formed primarily in the wear track in amounts roughly paralleling the fluorescence intensity. Some of the deposits were lubricating carbon and some nonlubricating silicon oxycarbide. Continuous high-temperature lubrication was possible by balancing deposit removal by wear with surface-chemical deposit formation rates. Raman, infrared, fluorescence, and other spectroscopies helped explain the process. Defect energy states within the large silicon nitride energy gap and dangling bonds appear to play a role.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Drug Induced Changes in Cell Organelles

1968 ◽  
Vol 26 ◽  
pp. 110-111
Author(s):  
Sarah A. Luse
Keyword(s):  
Clinical Medicine ◽  
Cell Organelles ◽  
Riboflavin Deficiency ◽  
Drug Induced ◽  
New Era ◽  
Health And Disease ◽  
In The Beginning ◽  
Cellular Pathology ◽  
Induced Changes ◽  
The Impact

In the mid-nineteenth century Virchow revolutionized pathology by introduction of the concept of “cellular pathology”. Today, a century later, this term has increasing significance in health and disease. We now are in the beginning of a new era in pathology, one which might well be termed “organelle pathology” or “subcellular pathology”. The impact of lysosomal diseases on clinical medicine exemplifies this role of pathology of organelles in elucidation of disease today.Another aspect of cell organelles of prime importance is their pathologic alteration by drugs, toxins, hormones and malnutrition. The sensitivity of cell organelles to minute alterations in their environment offers an accurate evaluation of the site of action of drugs in the study of both function and toxicity. Examples of mitochondrial lesions include the effect of DDD on the adrenal cortex, riboflavin deficiency on liver cells, elevated blood ammonia on the neuron and some 8-aminoquinolines on myocardium.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

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