Novel data on the spectra of photosensitized singlet-oxygen luminescence in the solution phase: detection of vibrationally excited monomols and dye-activated dimols of singlet oxygen

1993 ◽  
Author(s):  
Alexander A. Krasnovsky, Jr. ◽  
K. V. Neverov
Keyword(s):  
Singlet Oxygen ◽  
Solution Phase ◽  
Phase Detection ◽  
Vibrationally Excited

Nanomaterial-based biosensors using dual transducing elements for solution phase detection

The Analyst ◽  
2015 ◽  
Vol 140 (9) ◽  
pp. 2916-2943 ◽  
Author(s):  
Ning Li ◽  
Xiaodi Su ◽  
Yi Lu
Keyword(s):  
Design Principles ◽  
Solution Phase ◽  
Phase Detection ◽  
Recent Advances

This review describes the design principles of dual-transducer nanosensors and the recent advances in this field (“T” = target; “Trans.” in CL = Transducer).

Possible formation of singlet oxygen from vibrationally excited water

1984 ◽  
Vol 25 (2-4) ◽  
pp. 99-104 ◽  
Author(s):  
Ajit Singh ◽  
Grant W. Koroll ◽  
Stephen A. Antonsen
Keyword(s):  
Singlet Oxygen ◽  
Vibrationally Excited

Solution-phase detection of dual microRNA biomarkers in serum

2011 ◽  
Vol 402 (1) ◽  
pp. 543-550 ◽  
Author(s):  
David Broyles ◽  
Kyle Cissell ◽  
Manoj Kumar ◽  
Sapna Deo
Keyword(s):  
Solution Phase ◽  
Phase Detection

Singlet molecular oxygen and primary mechanisms of photo-oxidative damage of chloroplasts. Studies based on detection of oxygen and pigment phosphorescence

1994 ◽  
Vol 102 ◽  
pp. 219-235 ◽  
Author(s):  
A. A. Krasnovsky
Keyword(s):  
Quantum Yield ◽  
Singlet Oxygen ◽  
Photosynthetic Apparatus ◽  
Quantum Yields ◽  
Triplet States ◽  
Vibrationally Excited ◽  
Plant Materials ◽  
Phosphorescence Quenching ◽  
Singlet Oxygen Species ◽  
Pigment Aggregation

SynopsisPhotogeneration of singlet oxygen molecules (1O2), their vibrationally excited stateand dimols (1O2)2has been shown by measuring photosensitised delayed luminescence in pigment-containing media. All singlet oxygen species are formed as a result of energy transfer to O2from triplet pigment molecules. Monomeric pigment molecules are the most efficient singlet oxygen generators. The1O2quantum yields are 40–80% in aerobic solutions of monomeric chlorophylls and pheophytins. Pigment aggregation causes a strong decrease in singlet oxygen production. The1O2quantum yield in chloroplasts has been estimated using literature and experimental data on formation of the chlorophyll triplet states in the photosynthetic apparatus. The most probable value is 0.1%. One of the major sources of singlet oxygen is likely to be the triplet states of newly formed pigment molecules which are not quenched by carotenoids and can be detected by measuring low-temperature pigment phosphorescence. Quenching of singlet oxygen by the thylakoid components has been analysed and the1O2lifetime estimated. The data suggest that carotenoids and chlorophylls are the most efficient physical1O2quenchers and the1O2lifetime is about 70 ns in thylakoids. The quantum yield of1O2-induced pigment photodestruction was estimated to be about 10−6–10−5. This value is close to the quantum yield of chlorophyll photobleaching experimentally observed in aerobic suspensions of isolated chloroplasts. The intensity of pigment phosphorescence at 77 K correlates with the rate of chlorophyll photobleaching in plant materials. The data suggest that1O2generation by the pigment triplet states is the most likely reason for chloroplast photodamage. The intensity of pigment phosphorescence can be used as an index of the degree of plant photo-oxidative stress.

Solution Phase Isomerization of Vibrationally Excited Singlet Nitrenes to Vibrationally Excited 1,2-Didehydroazepine

2006 ◽  
Vol 128 (46) ◽  
pp. 14804-14805 ◽  
Author(s):  
Gotard T. Burdzinski ◽  
Chris T. Middleton ◽  
Terry L. Gustafson ◽  
Matthew S. Platz
Keyword(s):  
Solution Phase ◽  
Excited Singlet ◽  
Vibrationally Excited

scholarly journals Detection of Explosives by SERS Platform Using Metal Nanogap Substrates

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5567
Author(s):  
Samir Adhikari ◽  
Emmanuel K. Ampadu ◽  
Minjun Kim ◽  
Daegwon Noh ◽  
Eunsoon Oh ◽  
...  
Keyword(s):  
Hot Spot ◽  
Solution Phase ◽  
Excitation Wavelength ◽  
Phase Detection ◽  
Incident Power ◽  
Personal Safety ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Detection Of Explosives

Detecting trace amounts of explosives to ensure personal safety is important, and this is possible by using laser-based spectroscopy techniques. We performed surface-enhanced Raman scattering (SERS) using plasmonic nanogap substrates for the solution phase detection of some nitro-based compounds, taking advantage of the hot spot at the nanogap. An excitation wavelength of 785 nm with an incident power of as low as ≈0.1 mW was used to excite the nanogap substrates. Since both RDX and PETN cannot be dissolved in water, acetone was used as a solvent. TNT was dissolved in water as well as in hexane. The main SERS peaks of TNT, RDX, and PETN were clearly observed down to the order of picomolar concentration. The variations in SERS spectra observed from different explosives can be useful in distinguishing and identifying different nitro-based compounds. This result indicates that our nanogap substrates offer an effective approach for explosives identification.

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

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