Andrey Prosvirin

Laser and Plasma Technologies (LPT) has developed a sub-coating detection system, the LPT-S2. This handheld system is able to “see” through painted surfaces to detect incipient corrosion, image composite structures, and discover sub-surface defects.
Examination of aircraft and other military assets for corrosion and structural defects is still heavily dependent upon visual inspection methods, either with the unaided eye or with a flashlight. These techniques have traditionally been… Show more

Laser and Plasma Technologies (LPT) has developed a sub-coating detection system, the LPT-S2. This handheld system is able to “see” through painted surfaces to detect incipient corrosion, image composite structures, and discover sub-surface defects.
Examination of aircraft and other military assets for corrosion and structural defects is still heavily dependent upon visual inspection methods, either with the unaided eye or with a flashlight. These techniques have traditionally been unreliable, with detection of problem areas occurring only after defects have extended to larger areas where high cost repairs are required.
The LPT-S2 can be described as a handheld video imaging instrument engineered to penetrate coating systems. In order to resolve an image of the sub-coating surface, photons have to travel through the paint layers and reach the surface of the metal or composite. These photons must then return back through the paint to transmit surface information to a detector. The LPT-S2 is designed to generate and detect photons at wavelength bands transparent to many MIL-SPEC paint systems. Show less

UV irradiation is one of the most harmful exogenous factors for plants. Reactive oxygen species promote oxidative stress and can damage DNA. Carotenes are present in plants, in part, to prevent damage by scavenging these oxygenated radical species. The speed of response of the organism in production of carotenes is related to adaptation for survival. In vivo Raman microspectroscopy was applied to monitor the enhancement of carotene content in Coleus leaves when they were irradiated by low power… Show more

UV irradiation is one of the most harmful exogenous factors for plants. Reactive oxygen species promote oxidative stress and can damage DNA. Carotenes are present in plants, in part, to prevent damage by scavenging these oxygenated radical species. The speed of response of the organism in production of carotenes is related to adaptation for survival. In vivo Raman microspectroscopy was applied to monitor the enhancement of carotene content in Coleus leaves when they were irradiated by low power UV-light.
The spectroscopic analysis of different parts of the leaf showed strong carotene Raman signals arising from the blade area between the stems shows a marked increase in the signal intensity upon UV irradiation without any significant Raman shift changes. The main Raman shifts associated with chlorophyll and β-carotene in plant leaves changed with the increasing time of UV exposure. However, the band associated with lignin did not change significantly. The ratios of the Raman signal intensities of the chlorophyll and β-carotene to lignin were used to study UV induced changes in Coleus. By using the ratios between the two Raman bands, artifacts caused by the uneven surface, changes in the laser intensity and other measurement errors were overcome.
Raman spectra were obtained for two Coleus samples with different coloration. It was shown that, with respect to control samples, the carotene content in the leaves increased about two-fold, after exposure to UV- irradiation, followed by photo-degradation for UVA and UVB light. UVC radiation showed a different stress response.
These promising results may lead to the development of facile spectroscopic techniques to improve food quality and the use of UV light in greenhouses and for indoor plants. Our results indicate that Raman spectroscopy of carotene content in plants is a useful and simple tool for monitoring plant stress and analyzing UV-protective molecular species.
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Revolutionary instrumentation is currently being developed through a partnership between Texas A&M, Harbor Branch Oceanographic Institution, and WET Labs for the measurement of the backscattering coefficient bb and the total scattering coefficient b. For decades, simple instrumentation to obtain the important bb coefficient has been pursued, however the best available sensors rely on the accuracy of an empirical relation between measurements taken at specific angles and the total backscattering… Show more

Revolutionary instrumentation is currently being developed through a partnership between Texas A&M, Harbor Branch Oceanographic Institution, and WET Labs for the measurement of the backscattering coefficient bb and the total scattering coefficient b. For decades, simple instrumentation to obtain the important bb coefficient has been pursued, however the best available sensors rely on the accuracy of an empirical relation between measurements taken at specific angles and the total backscattering coefficient. The resulting data is thought to have accuracy in the range of 10% down to a few percent. This data is doubted due to the need for additional measurements or assumptions made about the phase function of the sample. The instrumentation being developed by Texas A&M and WET Labs will provide the first single direct measurement of bb without any prior assumptions about the phase function and will provide measurement accuracy of a few tenths of one percent. In order to measure the total scattering coefficient b, the instrument has adapted an inverted Beutell/Brewer (IBB) design developed at WET Labs into the bb sensor. The instrumentation that is being developed will have a transformational impact on light scattering studies in the oceans. The combined bb and b meter will provide unparalleled accuracy in determining the optical scattering and backscattering coefficients, which are very important in remote sensing and in-water bio-optical applications. This instrument has the potential to shed new light on the nature and distribution of scattering particulates. Show less

Three members of the family of trigonal bipyramidal
(TBP) complexes of general formula [M(tmphen)2]3-
[M0(CN)6]2 (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline)
or [M3M0
2], which are known to exhibit thermally
induced spin crossover and charge transfer, have been investigated
for optical and photomagnetic properties. The lightinduced
excited spin-state trapping (LIESST) effect found in
classical spin crossover compounds, such as [Fe(phen)2(NCS)2],
was explored for… Show more

Three members of the family of trigonal bipyramidal
(TBP) complexes of general formula [M(tmphen)2]3-
[M0(CN)6]2 (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline)
or [M3M0
2], which are known to exhibit thermally
induced spin crossover and charge transfer, have been investigated
for optical and photomagnetic properties. The lightinduced
excited spin-state trapping (LIESST) effect found in
classical spin crossover compounds, such as [Fe(phen)2(NCS)2],
was explored for the [Fe3Fe2] and [Fe3Co2] compounds.
Similarly, inspired by the light-induced charge-transfer properties
of K0.2Co1.4[Fe(CN)6] 3 6.9H2O and related Prussian blue materials, the possibility of photo-induced magnetic changes was
investigated for the [Co3Fe2] TBP complex. Optical reflectivity and magnetic susceptibility measurements were used to evaluate the
photoactivity of these compounds. A comparison of these data before and after light irradiation demonstrates that (i) the spin
crossover of the FeII centers in the [Fe3Fe2] and [Fe3Co2] analogues and the (ii) charge transfer events in the [Co3Fe2] complex
occur with temperature and irradiation. In addition, photomagnetic behavior is exhibited by all three compounds. The photoconversion
efficiency has been estimated at 20% of photo-induced high spin FeII centers in [Fe3Co2], 30% of paramagnetic
CoII-FeIII pairs in [Co3Fe2], and less than 2% of photo-induced high spin FeII centers in [Fe3Fe2]. Show less

To expand the field of new cyanide materials of the 5d elements, we incorporated the [Os(CN)6]3− anion into PB architectures in combination with the Co(II) cation. Herein, we report the first example of a photomagnetic PB analog containing Os(III) ions. In a similar vein as the prototypical CoFe PB analogs, this compound exhibits a wide variety of properties including Charge Transfer Induced Spin Transition (CTIST), Temperature Induced Excited Spin State Trapping (TIESST), and magnetic… Show more

To expand the field of new cyanide materials of the 5d elements, we incorporated the [Os(CN)6]3− anion into PB architectures in combination with the Co(II) cation. Herein, we report the first example of a photomagnetic PB analog containing Os(III) ions. In a similar vein as the prototypical CoFe PB analogs, this compound exhibits a wide variety of properties including Charge Transfer Induced Spin Transition (CTIST), Temperature Induced Excited Spin State Trapping (TIESST), and magnetic ordering. Show less

In this work, we present a detailed AC magnetic susceptibility investigation of the metamagnet {[Mn(OH)(CH3CO2)2]·CH3CO2H·H2O}∞ (1). Compound 1 was previously reported and the magnetic properties were investigated. The data revealed that the compound is a linear-chain antiferromagnet with a phase transition at TN = 6.1 K to an ordered antiferromagnetic state and a metamagnetic transition at approximately 1000 Oe from the antiferromagnetic phase to a paramagnetic phase. In this new study we… Show more

In this work, we present a detailed AC magnetic susceptibility investigation of the metamagnet {[Mn(OH)(CH3CO2)2]·CH3CO2H·H2O}∞ (1). Compound 1 was previously reported and the magnetic properties were investigated. The data revealed that the compound is a linear-chain antiferromagnet with a phase transition at TN = 6.1 K to an ordered antiferromagnetic state and a metamagnetic transition at approximately 1000 Oe from the antiferromagnetic phase to a paramagnetic phase. In this new study we report detailed AC susceptibility measurements which reveal frequency dependent data indicative of a slow relaxation process which was not previously described. These additional magnetic data support the conclusion that this compound is a rare example of an antiferromagnetic ordered system that displays magnetic relaxation properties induced by the intrinsic single chain magnet (SCM) properties of the canted homospin chains composing the material. Show less

Inorganic Chemistry Communications. 2013; 33, 1-5

Polyhedron, 2013; 58, 18-29

Solid State Nuclear Magnetic Resonance, 2009, 36(3), 129-136

Crystal Growth & Design, 2012, 12, 2662-2672

Microporous & Mesoporous Materials, 2009, 118(1-3), 78-86

Colloids and Surfaces, A: Physicochemical and Engineering Aspects, 2010, 357(1-3), 105-115.