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Jaan Laane - One of the best experts on this subject based on the ideXlab platform.
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Fluorescence Excitation and ultraviolet absorption spectra and theoretical calculations for benzocyclobutane vibrations and structure of its excited s1 π π electronic state
Journal of Chemical Physics, 2014Co-Authors: Hee Won Shin, Esther J Ocola, Sunghwan Kim, Jaan LaaneAbstract:The Fluorescence Excitation spectra of jet-cooled benzocyclobutane have been recorded and together with its ultraviolet absorption spectra have been used to assign the vibrational frequencies for this molecule in its S1(π,π*) electronic excited state. Theoretical calculations at the CASSCF(6,6)/aug-cc-pVTZ level of theory were carried out to compute the structure of the molecule in its excited state. The calculated structure was compared to that of the molecule in its electronic ground state as well as to the structures of related molecules in their S0 and S1(π,π*) electronic states. In each case the decreased π bonding in the electronic excited states results in longer carbon-carbon bonds in the benzene ring. The skeletal vibrational frequencies in the electronic excited state were readily assigned and these were compared to the ground state and to the frequencies of five similar molecules. The vibrational levels in both S0 and S1(π,π*) states were remarkably harmonic in contrast to the other bicyclic molecules. The decreases in the frequencies of the out-of-plane skeletal modes reflect the increased floppiness of these bicyclic molecules in their S1(π,π*) excited state.
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jet cooled Fluorescence Excitation spectrum carbonyl wagging and ring puckering potential energy functions of 3 cyclopenten 1 one in its s1 n π electronic excited state
Journal of Chemical Physics, 1995Co-Authors: Paul A. Sagear, Jaan LaaneAbstract:The jet‐cooled Fluorescence Excitation spectrum of 3‐cyclopenten‐1‐one has been recorded in the 308–330 nm region, and the electronic origin for the S1(n,π*) state of A2 symmetry was observed at 30 229 cm−1. The observed spectrum consists of more than 80 bands involving primarily ν3 (carbonyl stretch), ν29 (carbonyl out‐of‐plane wagging), and ν30 (ring puckering). Bands were also assigned to combinations with seven other vibrational modes. The energies for the v=0 to 11 quantum states of ν29 were measured and used to determine a one‐dimensional potential energy function. This function has energy minima at wagging angles of ±24° and a barrier to inversion of 939 cm−1. Four bands associated with ν30 were observed and were used to determine an asymmetric single‐minimum one‐dimensional ring‐puckering potential energy function for the S1(n,π*) state. The ring‐puckering energy levels in the ν29 vibrational excited states are little changed from the v=0 state indicating that there is little interaction between t...
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jet cooled Fluorescence Excitation spectra conformation and carbonyl wagging potential energy function of cyclopentanone and its deuterated isotopomers in the s1 n π electronic excited states
Journal of Chemical Physics, 1993Co-Authors: Jian Zhang, Wheyi Chiang, Jaan LaaneAbstract:The jet‐cooled Fluorescence Excitation spectra of cyclopentanone and its 2,2,5,5‐d4 isotopomer have been recorded in the 305–335 nm region. In addition, the spectra of d1, d2, and d3 species were obtained from isotopic mixtures. The electronic band origin of the d0 molecule for the S1 (n,π*) state of A2 symmetry occurs at 30 276 cm−1, while that of the d4 molecule is at 30 265 cm−1. More than 100 Fluorescence bands were assigned for each species. These arise from combinations of ν3 (C=O stretch), ν11 (ring‐angle bending), ν18 (ring twisting), ν25 (C=O out‐of‐plane wag), ν26 (ring bending), and ν36 (C=O in‐plane wag) and their vibrational excited states. The vibrational frequencies for ν3, ν11, and ν36 are significantly lower in the S1 state than the S0 ground state. However, the out‐of‐plane ring modes ν18 and ν26 are only slightly shifted. A progression observed for ν26 does indicate that in the S1 state, the bent ring conformation lies about 500 cm−1 above the ring‐twisting minimum and corresponds to a ...
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the jet cooled Fluorescence Excitation spectrum and ring bending potential energy function and conformation of 2 cyclopenten 1 one in the s1 n π electronic excited state
Journal of Chemical Physics, 1991Co-Authors: C M Cheatham, Jaan LaaneAbstract:The jet‐cooled Fluorescence Excitation spectra of 2‐cyclopenten‐1‐one and its 5,5‐d2 isotopomer have been recorded in the 370–340 nm region. The electronic origin for the undeuterated species occurs at 27 210 cm−1 for the S1(n,π*) electronic excited state. The vibrational frequencies for the three carbonyl motions and the nine ring modes were observed for the excited state. Bands at 67, 158, and 256 cm−1 for the d0 species, at 63, 147, and 240 cm−1 for the 5‐d1 isotopomer, and at 59, 138, and 227 cm−1 for the d2 species were assigned to the ring‐puckering motion in the S1 state. A single one‐dimensional potential‐energy function accurately fits the data for all three isotopomers. This function is nearly purely quartic in character and shows the ring to be planar in the electronic excited state. However, it has become less rigid, and this is ascribed to a decrease in initial angle strain within the ring. The C=O and C=C stretching frequencies occur at 1418 and 1357 cm−1 for the d0 molecule. The ring‐twisti...
S A Baghoth - One of the best experts on this subject based on the ideXlab platform.
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tracking natural organic matter nom in a drinking water treatment plant using Fluorescence Excitation emission matrices and parafac
Water Research, 2011Co-Authors: S A Baghoth, Saroj K Sharma, Gary AmyAbstract:Natural organic matter (NOM) in water samples from a drinking water treatment train was characterized using Fluorescence Excitation emission matrices (F-EEMs) and parallel factor analysis (PARAFAC). A seven component PARAFAC model was developed and validated using 147 F-EEMs of water samples from two full-scale water treatment plants. It was found that the fluorescent components have spectral features similar to those previously extracted from F-EEMs of dissolved organic matter (DOM) from diverse aquatic environments. Five of these components are humic-like with a terrestrial, anthropogenic or marine origin, while two are protein-like with Fluorescence spectra similar to those of tryptophan-like and tyrosine-like fluorophores. A correlation analysis was carried out for samples of one treatment plant between the maximum Fluorescence intensities (F(max)) of the seven PARAFAC components and NOM fractions (humics, building blocks, neutrals, biopolymers and low molecular weight acids) of the same sample obtained using liquid chromatography with organic carbon detection (LC-OCD). There were significant correlations (p < 0.01) between sample DOC concentration, UVA(254), and F(max) for the seven PARAFAC components and DOC concentrations of the LC-OCD fractions. Three of the humic-like components showed slightly better predictions of DOC and humic fraction concentrations than UVA(254.) Tryptophan-like and tyrosine-like components correlated positively with the biopolymer fraction. These results demonstrate that fluorescent components extracted from F-EEMs using PARAFAC could be related to previously defined NOM fractions and that they could provide an alternative tool for evaluating the removal of NOM fractions of interest during water treatment.
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tracking natural organic matter nom in a drinking water treatment plant using Fluorescence Excitation emission matrices and parafac
Water Research, 2011Co-Authors: S A Baghoth, Saroj K SharmaAbstract:Abstract Natural organic matter (NOM) in water samples from a drinking water treatment train was characterized using Fluorescence Excitation emission matrices (F-EEMs) and parallel factor analysis (PARAFAC). A seven component PARAFAC model was developed and validated using 147 F-EEMs of water samples from two full-scale water treatment plants. It was found that the fluorescent components have spectral features similar to those previously extracted from F-EEMs of dissolved organic matter (DOM) from diverse aquatic environments. Five of these components are humic-like with a terrestrial, anthropogenic or marine origin, while two are protein-like with Fluorescence spectra similar to those of tryptophan-like and tyrosine-like fluorophores. A correlation analysis was carried out for samples of one treatment plant between the maximum Fluorescence intensities ( F max ) of the seven PARAFAC components and NOM fractions (humics, building blocks, neutrals, biopolymers and low molecular weight acids) of the same sample obtained using liquid chromatography with organic carbon detection (LC-OCD). There were significant correlations ( p 254 , and F max for the seven PARAFAC components and DOC concentrations of the LC-OCD fractions. Three of the humic-like components showed slightly better predictions of DOC and humic fraction concentrations than UVA 254. Tryptophan-like and tyrosine-like components correlated positively with the biopolymer fraction. These results demonstrate that fluorescent components extracted from F-EEMs using PARAFAC could be related to previously defined NOM fractions and that they could provide an alternative tool for evaluating the removal of NOM fractions of interest during water treatment.
Gary Amy - One of the best experts on this subject based on the ideXlab platform.
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tracking natural organic matter nom in a drinking water treatment plant using Fluorescence Excitation emission matrices and parafac
Water Research, 2011Co-Authors: S A Baghoth, Saroj K Sharma, Gary AmyAbstract:Natural organic matter (NOM) in water samples from a drinking water treatment train was characterized using Fluorescence Excitation emission matrices (F-EEMs) and parallel factor analysis (PARAFAC). A seven component PARAFAC model was developed and validated using 147 F-EEMs of water samples from two full-scale water treatment plants. It was found that the fluorescent components have spectral features similar to those previously extracted from F-EEMs of dissolved organic matter (DOM) from diverse aquatic environments. Five of these components are humic-like with a terrestrial, anthropogenic or marine origin, while two are protein-like with Fluorescence spectra similar to those of tryptophan-like and tyrosine-like fluorophores. A correlation analysis was carried out for samples of one treatment plant between the maximum Fluorescence intensities (F(max)) of the seven PARAFAC components and NOM fractions (humics, building blocks, neutrals, biopolymers and low molecular weight acids) of the same sample obtained using liquid chromatography with organic carbon detection (LC-OCD). There were significant correlations (p < 0.01) between sample DOC concentration, UVA(254), and F(max) for the seven PARAFAC components and DOC concentrations of the LC-OCD fractions. Three of the humic-like components showed slightly better predictions of DOC and humic fraction concentrations than UVA(254.) Tryptophan-like and tyrosine-like components correlated positively with the biopolymer fraction. These results demonstrate that fluorescent components extracted from F-EEMs using PARAFAC could be related to previously defined NOM fractions and that they could provide an alternative tool for evaluating the removal of NOM fractions of interest during water treatment.
Walfre Franco - One of the best experts on this subject based on the ideXlab platform.
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noninvasive assessment of mycotic nail tissue using an ultraviolet Fluorescence Excitation imaging system
Lasers in Surgery and Medicine, 2021Co-Authors: Vinzent Kevin Ortner, Walfre Franco, Merete Haedersdal, Peter A PhilipsenAbstract:BACKGROUND AND OBJECTIVES Mycological diagnosis of onychomycosis is based on direct microscopy using external fluorophores to visualize fungal tissue in nail samples and agar culture. Ultraviolet Fluorescence Excitation imaging (u-FEI) has shown potential in monitoring biological processes by exploiting variations in autoFluorescence. This study aimed at assessing the potential of a handheld u-FEI system as a practical screening tool for fungal nail infections. STUDY DESIGN/MATERIALS AND METHODS Ninety samples from 29 patients with microscopy-confirmed fungal infection and 10 control samples from healthy participants were collected (n = 100). Using a prototype u-FEI system (single bandpass 25 mm filter with a central pass wavelength of 340 nm and a bandwidth of 12 nm, 295 nm Excitation flash, resolution of 640 × 480), images of all samples were acquired under standardized conditions. Average and maximum Fluorescence intensity image values in arbitrary units (AU) of manually delineated regions of interests were quantitated and statistically assessed for significant differences between healthy and mycotic samples. RESULTS UV-images clearly depicted all 100 nail samples, with a visibly stronger signal in infected samples. Statistically significant differences (P 0.9). Analysis of Fluorescence measurements of the reference standard demonstrated very low variation (coefficient of variation = 0.62%) CONCLUSION: Quantitation of u-FEI intensities enables differentiation between healthy and mycotic nail samples, constituting a potential point-of-care tool for cost-effective screening for onychomycosis at a primary care level. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
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visualization of neo epidermis formation and evaluation of wound closure using uv Fluorescence Excitation imaging at two wavelengths conference presentation
Photonics in Dermatology and Plastic Surgery 2019, 2019Co-Authors: Ying Wang, Rox R Anderson, Wenli Cai, Kezhi Kong, Xueyuan Jia, Walfre FrancoAbstract:UV Fluorescence Excitation Imaging (u-FEI) is able to visualize the re-epithelialization of skin wounds at 295 nm Excitation wavelength. In this work, we investigated the feasibility of using u-FEI at 295 and 335 nm to visualize the formation of neo-epidermis and evaluate wound closure of partial and full-thickness skin wounds in an animal model. Partial and full-thickness skin wounds were created in the tail of rats. Wounds were imaged at different time points using u-FEI at 295/340 nm and 335/395 nm Excitation/emission wavelengths, which correspond to the Fluorescence ascribed to tryptophan moieties and pepsin-digestible collagen crosslinks. Because of their penetration depth, these wavelengths probe superficial and deeper fluorophores. Biopsies were collected at specific time points for histology and immunohistology analysis. Neo-epidermis had higher Fluorescence intensity at 295 nm than normal skin and lasted one week in both partial and full-thickness skin wounds, then decreased to normal skin intensity values in partial-thickness wounds or decreased even further in full-thickness wounds. In contrast, the Fluorescence from the 335 nm Excitation band began to increase when the Fluorescence at 295 nm was decreasing and show uniform Fluorescence distribution when the wound was fully closed. H&E and immunohistology show that Fluorescence intensity changes at 295 nm wavelength correlates with keratinocytes proliferation. The combined Fluorescence at 295 and 335 nm Excitation wavelengths may be useful in evaluating short and mid-term wound healing processes, in particular, formation of neo-epidermis and wound closure.
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uv Fluorescence Excitation imaging of healing of wounds in skin evaluation of wound closure in organ culture model
Lasers in Surgery and Medicine, 2016Co-Authors: Ying Wang, Enoch Gutierrezherrera, Antonio Ortegamartinez, Rox R Anderson, Walfre FrancoAbstract:Background and Objective Molecules native to tissue that fluoresce upon light Excitation can serve as reporters of cellular activity and protein structure. In skin, the Fluorescence ascribed to tryptophan is a marker of cellular proliferation, whereas the Fluorescence ascribed to cross-links of collagen is a structural marker. In this work, we introduce and demonstrate a simple but robust optical method to image the functional process of epithelialization and the exposed dermal collagen in wound healing of human skin in an organ culture model. Materials and Methods Non-closing non-grafted, partial closing non-grafted, and grafted wounds were created in ex vivo human skin and kept in culture. A wide-field UV Fluorescence Excitation imaging system was used to visualize epithelialization of the exposed dermis and quantitate wound area, closure, and gap. Histology (H&E staining) was also used to evaluate epithelialization. Results The endogenous Fluorescence Excitation of cross-links of collagen at 335 nm clearly shows the dermis missing epithelium, while the endogenous Fluorescence Excitation of tryptophan at 295 nm shows keratinocytes in higher proliferating state. The size of the non-closing wound was 11.4 ± 1.8 mm and remained constant during the observation period, while the partial-close wound reached 65.5 ± 4.9% closure by day 16. Evaluations of wound gaps using Fluorescence Excitation images and histology images are in agreement. Conclusions We have established a Fluorescence imaging method for studying epithelialization processes, evaluating keratinocyte proliferation, and quantitating closure during wound healing of skin in an organ culture model: the dermal Fluorescence of pepsin-digestible collagen cross-links can be used to quantitate wound size, closure extents, and gaps; and, the epidermal Fluorescence ascribed to tryptophan can be used to monitor and quantitate functional states of epithelialization. UV Fluorescence Excitation imaging has the potential to become a valuable tool for research, diagnostic and educational purposes on evaluating the healing of wounds. Lasers Surg. Med. 48:678–685, 2016. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.
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Fluorescence Excitation photography of epidermal cellular proliferation
British Journal of Dermatology, 2016Co-Authors: Enoch Gutierrezherrera, A E Ortiz, Apostolos G Doukas, Walfre FrancoAbstract:Summary Background Fluorescence Excitation provides the ability to interrogate innate molecules whose radiation emission correlates with specific functional states of tissue. Objectives The present study demonstrates the effectiveness of a novel ultraviolet (UV) Fluorescence Excitation photography system in its ability to image rapidly proliferating epidermal skin lesions by capturing endogenous Fluorescence emissions attributed to tryptophan. Methods A clinical prototype UV Fluorescence Excitation photography system was used to acquire images of endogenous Fluorescence ascribed to tryptophan. Results Twelve human subjects and 11 ex vivo samples with various skin lesions consistently exhibited increased endogenous Fluorescence at 340-nm wavelength upon Excitation at 295 nm in rapid epidermal proliferations, including psoriasis, actinic keratoses and basal cell carcinoma, compared with surrounding normal skin. In contrast, nonproliferating lesions showed decreased Fluorescence. Conclusions This simple but robust point-and-shoot imaging system may offer a clinically useful, noncontact, noninvasive device for the diagnosis and detection of skin disease. As opposed to structural imaging modalities, Fluorescence Excitation imaging at 295/340-nm wavelengths offers high-sensitivity, wide-field functional imaging of cellular proliferation without the need for externally applied dyes or lengthy image processing. Furthermore, the image is instantly available and does not require interpretation or reconstruction.
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evaluation of cell and matrix mechanics using Fluorescence Excitation spectroscopy feasibility study in collagen gels containing fibroblasts
Lasers in Surgery and Medicine, 2016Co-Authors: Juan Pablo Padillamartinez, Ruisheng Wang, Walfre FrancoAbstract:Background and Objective Collagen gels containing cells are commonly used in tissue engineering, wound healing, and cancer research to investigate the interplay between cells and the extracellular matrix (ECM), as changes in the density and stiffness of the microenvironment are known to play a role in many diseases or pathological conditions. In these gels, the stiffness is regularly determined using destructive methods, such as indentation and tensile tests. Certain molecules native to cells and the ECM display Fluorescence upon irradiation with ultraviolet light. The objective of the present study was to investigate the feasibility of using the endogenous, or innate, Fluorescence of collagen gels containing fibroblasts as an optical marker to evaluate changes in the mechanical properties of the ECM. Materials and Methods Human foreskin fibroblasts cells at concentrations of 50,000 and 100,000 cells/ml were cultured in three-dimensional gels of type I collagen for 16 days. Fibroblast cells remodeled the ECM, contracting and increasing the stiffness of the gel. During this remodeling process, changes in mechanical properties and Fluorescence were measured with an indentation test and a spectrofluorometer, respectively. Force and displacement measurements from the indentation test were used to calculate the elastic modulus of the gel. Maps of Fluorescence intensity, at Excitation/emission of 240–520/290–530 nm, were used to identify the wavelengths of interest. Results Fluorescence Excitation/emission maps exhibited two distinct Excitation/emission bands whose intensities increased as the fibroblasts remodeled and increased the stiffness of the ECM: The 290/340 nm band ascribed to tryptophan and the 330/390 nm band ascribed to cross-links of collagen (pepsin-digestible cross-links). A Spearman correlation analysis, between the elastic modulus of the gel containing fibroblasts and the Fluorescence of cross-links of collagen, resulted in R = 0.95 (P < 0.05) and R = 0.77 (P = 0.12) for 50,000 and 100,000 cells/ml, respectively. Conclusions The endogenous Fluorescence intensity ascribed to pepsin-digestible cross-links of collagen may serve as an optical marker to evaluate changes in the mechanical properties of the ECM; this is relevant to collagenous tissues for which pathological states are related to mechanical alterations, such as keratoconus in cornea and osteoarthritis in articular cartilage. Lasers Surg. Med. © 2016 Wiley Periodicals, Inc.
Saroj K Sharma - One of the best experts on this subject based on the ideXlab platform.
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tracking natural organic matter nom in a drinking water treatment plant using Fluorescence Excitation emission matrices and parafac
Water Research, 2011Co-Authors: S A Baghoth, Saroj K Sharma, Gary AmyAbstract:Natural organic matter (NOM) in water samples from a drinking water treatment train was characterized using Fluorescence Excitation emission matrices (F-EEMs) and parallel factor analysis (PARAFAC). A seven component PARAFAC model was developed and validated using 147 F-EEMs of water samples from two full-scale water treatment plants. It was found that the fluorescent components have spectral features similar to those previously extracted from F-EEMs of dissolved organic matter (DOM) from diverse aquatic environments. Five of these components are humic-like with a terrestrial, anthropogenic or marine origin, while two are protein-like with Fluorescence spectra similar to those of tryptophan-like and tyrosine-like fluorophores. A correlation analysis was carried out for samples of one treatment plant between the maximum Fluorescence intensities (F(max)) of the seven PARAFAC components and NOM fractions (humics, building blocks, neutrals, biopolymers and low molecular weight acids) of the same sample obtained using liquid chromatography with organic carbon detection (LC-OCD). There were significant correlations (p < 0.01) between sample DOC concentration, UVA(254), and F(max) for the seven PARAFAC components and DOC concentrations of the LC-OCD fractions. Three of the humic-like components showed slightly better predictions of DOC and humic fraction concentrations than UVA(254.) Tryptophan-like and tyrosine-like components correlated positively with the biopolymer fraction. These results demonstrate that fluorescent components extracted from F-EEMs using PARAFAC could be related to previously defined NOM fractions and that they could provide an alternative tool for evaluating the removal of NOM fractions of interest during water treatment.
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tracking natural organic matter nom in a drinking water treatment plant using Fluorescence Excitation emission matrices and parafac
Water Research, 2011Co-Authors: S A Baghoth, Saroj K SharmaAbstract:Abstract Natural organic matter (NOM) in water samples from a drinking water treatment train was characterized using Fluorescence Excitation emission matrices (F-EEMs) and parallel factor analysis (PARAFAC). A seven component PARAFAC model was developed and validated using 147 F-EEMs of water samples from two full-scale water treatment plants. It was found that the fluorescent components have spectral features similar to those previously extracted from F-EEMs of dissolved organic matter (DOM) from diverse aquatic environments. Five of these components are humic-like with a terrestrial, anthropogenic or marine origin, while two are protein-like with Fluorescence spectra similar to those of tryptophan-like and tyrosine-like fluorophores. A correlation analysis was carried out for samples of one treatment plant between the maximum Fluorescence intensities ( F max ) of the seven PARAFAC components and NOM fractions (humics, building blocks, neutrals, biopolymers and low molecular weight acids) of the same sample obtained using liquid chromatography with organic carbon detection (LC-OCD). There were significant correlations ( p 254 , and F max for the seven PARAFAC components and DOC concentrations of the LC-OCD fractions. Three of the humic-like components showed slightly better predictions of DOC and humic fraction concentrations than UVA 254. Tryptophan-like and tyrosine-like components correlated positively with the biopolymer fraction. These results demonstrate that fluorescent components extracted from F-EEMs using PARAFAC could be related to previously defined NOM fractions and that they could provide an alternative tool for evaluating the removal of NOM fractions of interest during water treatment.