SEARCH · PubMed Health

Results for “PHOSPHORESCENCE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources

PubMed2005

Molecularly imprinted polymers based on iodinated monomers for selective room-temperature phosphorescence optosensing of fluoranthene in water.

Aiming at enhancing the advantages of traditional molecularly imprinted polymers (MIPs) for chemical sensing, a new MIP design approach introducing an internal heavy atom in their polymeric structure is described. Based on the heavy-atom effect, the novel polymer allows one to perform room-temperature phosphorescence (RTP) transduction of the analyte. The synergic combination of a tailor-made MIP recognition with a selective RTP detection is a novel concept for optosensing devices which is assessed here for simple and highly selective determination of trace amounts of fluoranthene in water. The noncovalent MIP was synthesized using the laboratory-synthesized tetraiodobisphenol A as one of the polymeric precursors and fluoranthene as template. In the presence of an oxygen scavenger, the iodide included in the polymeric structure induced efficient RTP emission from the analyte, once recognized by the MIP. The developed optosensing system has demonstrated a high specificity for fluoranthene against other polycyclic aromatic hydrocarbons. Detection limit for the target molecule was 35 ng/L (5-mL sample injections), and the linear range extended above 100 microg/L of the analyte. The polymer can be easily regenerated for subsequent sample injections (at least up to 450 cycles) with acetonitrile. The synthesized sensing material showed good stability for at least 6 months after preparation. The feasibility of monitoring fluoranthene in real samples was successfully evaluated through the analysis of five spiked river water samples.

Journal Article↗

PubMed1999

Determination of benzo[a]pyrene-DNA adducts by solid-matrix phosphorescence.

It has been demonstrated for the first time that linear relationships can be obtained between the solid-matrix phosphorescence (SMP) and the percent modification of benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts. The samples of DNA were modified with BPDE at levels of 5.0 x 10(-3), 1.0 x 10(-3), 5.0 x 10(-4), 1.0 x 10(-4), 5.0 x 10(-5), and 1.0 x 10(-5%). In addition, the changes in the SMP intensities of a given percentage of DNA adduct were investigated as a function of sample size, and linear relationships were also acquired. With the different percentages of modified DNA, very good reproducibility of the SMP signals was obtained. Data were acquired with both Whatman 1PS paper and 30% TlNO3/sodium acetate as solid matrixes. The limit of detection for the BPDE-DNA adducts was 2 adducts in 10(7) bases for both Whatman 1PS paper and 30% TlNO3/sodium acetate. In addition, it was shown that it would be important to develop a standard procedure for the preparation of the BPDE-DNA samples if different batches of DNA were used in the preparation procedure.

Benzo(a)pyrene↗

PubMed2000

Phosphorescent oxygen sensors utilizing sulfur-nitrogen-phosphorous polymer matrixes: synthesis, characterization, and evaluation of poly(thionylphosphazene)-b-poly(tetrahydrofuran) block copolymers

We examine the use of thionylphosphazene-based block copolymers as matrixes for oxygen sensor applications. Poly(aminothionylphosphazene)-b-poly(tetrahydrofuran) (PATPy-PTHFx) block copolymers were prepared via reaction of ring-opened poly(chlorothionylphosphazene) with THF and subsequently with excess n-butylamine (to form PBATPy-PTHFx) or methylamine (to form PMATPy-PTHFx). The block copolymers were characterized by NMR, gel permeation chromatography, and differential scanning calorimetry. Films of PBATPy-PTHFx block copolymers containing platinum octaethylporphyrin or [Ru(dpp)3]Cl2 (dpp = 4,7-diphenyl-1,10-phenanthroline) as the oxygen-sensitive chromophore were prepared, and time-scan experiments were carried out to determine the diffusion coefficients, Do2, and solubilities, So2, of oxygen therein. Despite microphase separation, the data fit well to a simple Fick's law description of oxygen diffusion and gave Do2 values smaller than that for the n-butylamino-substituted PBATP635. For films freshly annealed above the melting point of PTHFx, the Do2 values were 35-50% (dye-dependent) larger than after aging 3 days at room temperature. Films with [Ru(dpp)3]Cl2 as the dye were evaluated as media for phosphorescent pressure-sensing. The dye-containing polymer films exhibit linear Stern-Volmer-like plots, even at high dye concentrations, as well as good photostability, and significantly higher sensitivity to oxygen quenching than simple mixtures of the analogous homopolymers.

Journal Article↗

PubMed1983

Penetration of dioxygen into proteins studied by quenching of phosphorescence and fluorescence.

Experiments were done to measure the ability of dioxygen to collisionally quench the phosphorescent and fluorescent tryptophans in alcohol dehydrogenase and alkaline phosphatase. In all cases, luminescence is quenched with rate constants close to 1 x 10(9) M-1 s-1. The rate of reaching the buried tryptophans is little affected by solvent viscosity due to added glycerol. Quenching by dioxygen is not due to a protein-opening reaction. It appears to be rate limited by internal protein diffusion rather than at the entry step. Dioxygen appears to enter the proteins directly, as in liquidlike diffusion, rather than through transiently forming channels that are only present a small fraction of the time. A high-pressure oxygen system is described that considerably facilitates fluorescence quenching experiments.

Alcohol Dehydrogenase↗

PubMed1984

Comparative phosphorescence and optically detected magnetic resonance studies of pig and yeast glyceraldehyde-3-phosphate dehydrogenase.

A comparative optically detected magnetic resonance (ODMR) investigation has been made of the tryptophan (Trp) residues of glyceraldehyde-3-phosphate dehydrogenase (GAPD) from pig and yeast. We find that pig GAPD emits phosphorescence from only two of the three distinct Trp sites, while yeast GAPD exhibits resolved 0,0-bands from all three Trps. Heavy atom effects observed in the CH3Hg(II)-sulfhydryl complex of pig GAPD resemble closely those reported earlier for the analogous rabbit GAPD-CH3Hg(II) complex. Trp-310, with a 0,0-band at 416 nm, undergoes a selective heavy atom perturbation as a result of CH3Hg(II) binding to the nearby Cys-281. The 416-nm peak in yeast GAPD is assigned to Trp-310 on the basis of ODMR, but no heavy atom effect of CH3Hg(II)-sulfhydryl complexing is observed because of the absence of Cys-281 in yeast, thus supporting this assignment. The 406-nm 0,0-bands of pig and rabbit GAPD and the 409-nm band of yeast GAPD are assigned to Trp-193, located in a subunit contact region. This residue is solvent exposed in the yeast enzyme but appears to be buried in a polar environment in the mammalian GAPD. These differences may be related to variations in subunit co-operativity between species. Trp-84 appears to be quenched in pig and rabbit GAPD, most likely by His-108. In yeast GAPD, on the other hand, Trp-84 is not quenched, probably because His-108 is further removed. The Trp-84 0,0-band of the yeast enzyme peaks at 420 nm, making it the most red-shifted Trp origin reported thus far.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Microsecond rotational dynamics of phosphorescent-labeled muscle cross-bridges.

We have measured the microsecond rotational motions of myosin heads in muscle cross-bridges under physiological ionic conditions at 4 degrees C, by detecting the time-resolved phosphorescence of eosin-maleimide covalently attached to heads in skeletal muscle myofibrils. The anisotropy decay of heads in rigor (no ATP) is constant over the time range from 0.5 to 200 microsecond, indicating that they do not undergo rotational motion in this time range. In the presence of 5 mM MgATP, however, heads undergo complex rotational motion with correlation times of about 5 and 40 microsecond. The motion of heads in relaxed myofibrils is restricted out to 1 ms, as indicated by a nonzero value of the residual anisotropy. The anisotropy decay of eosin-labeled myosin, extracted from labeled myofibrils, also exhibits complex decay on the 200-microsecond time scale when assembled into synthetic thick filaments. The correlation times and amplitudes of heads in filaments (under the same ionic conditions as the myofibril experiments) are unaffected by MgATP and very similar to the values for heads in relaxed myofibrils. The larger residual anisotropy and longer correlation times seen in myofibrils are consistent with a restriction of rotational motion in the confines of the myofibril protein lattice. These are the first time-resolved measurements under physiological conditions of the rotational motions of cross-bridges in the microsecond time range.

Animals↗

PubMed1990

Time-resolved rotational dynamics of phosphorescent-labeled myosin heads in contracting muscle fibers.

We have measured the microsecond rotational motions of myosin heads in contracting rabbit psoas muscle fibers by detecting the transient phosphorescence anisotropy of eosin-5-maleimide attached specifically to the myosin head. Experiments were performed on small bundles (10-20 fibers) of glycerinated rabbit psoas muscle fibers at 4 degrees C. The isometric tension and physiological ATPase activity of activated fibers were unaffected by labeling 60-80% of the heads. Following excitation of the probes by a 10-ns laser pulse polarized parallel to the fiber axis, the time-resolved emission anisotropy of muscle fibers in rigor (no ATP) showed no decay from 1 microsecond to 1 ms (r infinity = 0.095), indicating that all heads are rigidly attached to actin on this time scale. In relaxation (5 mM MgATP but no Ca2+), the anisotropy decayed substantially over the microsecond time range, from an initial anisotropy (r0) of 0.066 to a final anisotropy (r infinity) of 0.034, indicating large-amplitude rotational motions with correlation times of about 10 and 150 microseconds and an overall angular range of 40-50 degrees. In isometric contraction (MgATP plus saturating Ca2+), the amplitude of the anisotropy decay (and thus the amplitude of the microsecond motion) is slightly less than in relaxation, and the rotational correlation times are about twice as long, indicating slower motions than those observed in relaxation. While the residual anisotropy (at 1 ms) in contraction is much closer to that in relaxation than in rigor, the initial anisotropy (at 1 microsecond) is approximately equidistant between those of rigor and relaxation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1981

Investigation of the nature of enzyme--coenzyme interactions in binary and ternary complexes of liver alcohol dehydrogenase with coenzymes, coenzyme analogues, and substrate analogues by ultraviolet absorption and phosphorescence spectroscopy.

The difference spectra of binary and ternary complexes of horse liver alcohol dehydrogenase with oxidized and reduced nicotinamide adenine dinucleotides, nicotinamide 1,N6-ethenoadenine dinucleotide, and adenosine diphosphate ribose along with a number of substrate analogues have been measured. These spectra bear a very close resemblance to those obtained by perturbation of the coenzyme(s) and their analogues by acid, NaCl, dioxane, or tert-butyl alcohol. It is inferred that the coenzymes experience a combination of ionic and nonpolar environments at the adenine binding site of the enzyme. This is borne out by published X-ray crystallographic results. The phosphorescence spectra do not indicate the presence of ionized tyrosine in ternary complexes invovling enzyme, coenzyme, and substrate analogues. The ultraviolet spectra can be explained as arising from the perturbation of the coenzyme chromophores upon binding to the enzyme without having to invoke tyrosine ionization.

Adenosine Diphosphate Ribose↗

PubMed1981

Quenching of enzyme-generated acetone phosphorescence by indole compounds: stereospecific effects of D- and L-tryptophan. Photochemical-like effects.

Indole compounds efficiently quench the acetone phosphorescence observed during the horseradish peroxidase catalyzed aerobic oxidation of isobutyraldehyde. Different types of Stern-Volmer plots are observed: linear, linear with two slopes, and downward- and upward-curved plots. The complexity probably stems from the operation of both dynamic and static quenching, coupled with different efficiencies of quenching of various acetone triplet populations. Binding to the enzyme may also occur, especially in the case of L-tryptophan. The different Stern-Volmer behavior of D- and L-tryptophan fully confirms that the acetone triplet is generated within the enzyme and not free in solution. This chiral discrimination toward an enzymically generated electronically excited species is novel. It is tentatively postulated that a long-range triplet-triplet exciton transfer occurs; the excited triplet indole then undergoes photochemical-like alterations.

Acetone↗

PubMed2003

Monitoring of actin unfolding by room temperature tryptophan phosphorescence.

Slow intramolecular mobility of native and inactivated actin from rabbit skeletal muscle during the process of protein unfolding induced by GdnHCl was studied using tryptophan room temperature phosphorescence (RTP). By this method, the conclusion was confirmed that an essentially unfolded intermediate preceded the formation of inactivated actin [Turoverov et al. Biochemistry (2002) 41, 1014-1019]. It was found that the kinetic intermediate generated at the early stage of protein denaturation has no tryptophan RTP, suggesting the high lability of its structure. Symbate changes of integral intensity and the mean lifetime of RTP during the U* --> I transition suggests a gradual increase of the number of monomers incorporated in the associate (U* --> I(1)... --> I(n)... --> I(15)), which is accompanied by an increase of structural rigidity. The rate of inactivated actin formation (I identical with I(15)) is shown to increase with the increase of protein concentration. It is shown that, no matter what the means of inactivation, actin transition to the inactivated state is accompanied by a significant increase of both integral intensity and the mean lifetime of RTP, suggesting that inactivated actin has a rigid structure.

Actins↗

PubMed1998

Phosphorescence and optically detected magnetic resonance characterization of the environments of tryptophan analogues in staphylococcal nuclease, its V66W mutant, and Delta 137-149 fragment.

Phosphorescence and optically detected magnetic resonance (ODMR) measurements are reported on the triplet states of the tryptophan analogues, 7-azatryptophan (7AW), 5-hydroxytryptophan (5HW), and 4-, 5-, and 6-fluorotryptophan (4FW, 5FW, 6FW), when incorporated at position 140 of wild-type Staphylococcal nuclease (7AW-nuclease, etc. ), positions 66 and 140 of its V66W mutant (7AW-V66W, etc.), and the deletion fragment of the latter, Delta 137-149 (7AW-V66W', etc.). These measurements point to the retention of protein structure at position 140 in each of the wild-type nuclease analogues. Substitution of the analogue at both tryptophan sites of V66W leads to structured sites with differentiated triplet-state properties for all analogues except 7AW-V66W, whose structure is destabilized. 5HW-V66W' is the only fragment that apparently lacks structure at position 66. All other V66W' analogues exhibit a structured environment at position 66 (4FW-V66W' was not studied), but in each case this site can be differentiated readily from the corresponding site in intact V66W. 7AW-V66W' is resolved by ODMR into two discrete structures with slightly differing zero field splittings (ZFS). Interaction of the protein with 5HW at position 66 of 5HW-V66W induces a 2-fold increase in the ZFS E parameter, which is reduced to its normal value upon formation of the fragment, 5HW-V66W'. Analogous effects occur for 5FW, but on a smaller scale.

5-Hydroxytryptophan↗

PubMed1999

Ligand-induced conformational changes in lactose repressor: a phosphorescence and ODMR study of single-tryptophan mutants.

Phosphorescence and optically detected magnetic resonance (ODMR) measurements are reported on four single-tryptophan mutants of lac repressor protein from Escherichia coli: H74W/Wless, W201Y, Y273W/Wless, and F293W/Wless, where Wless represents a protein background containing the double mutation W201Y/W220Y. The single-tryptophan residues are located in the protein core region, either in the monomer-monomer interface of the tetrameric protein or in the region of the inducer binding cleft. Inducer binding elicits large changes in the energy (0,0-band wavelength shifts) and zero-field splitting energies (ZFS) of the triplet states for each of the mutant proteins except W201Y which exhibits more modest effects. F293W/Wless exists in two distinguishable conformations, only one of which appears to be sensitive to the presence of inducer. These effects of inducer binding can be attributed to a conformational change that alters specific polar interactions that occur at each affected tryptophan site. Changes in the tryptophan triplet state indicator depend on the existence of specific polar interactions that are altered by local atomic relocations.

Amino Acid Substitution↗

PubMed1999

Rotational dynamics of the regulatory light chain in scallop muscle detected by time-resolved phosphorescence anisotropy.

We have used time-resolved phosphorescence anisotropy (TPA) to study the rotational dynamics of chicken gizzard regulatory light chain (RLC) bound to scallop adductor muscle myofibrils in key physiological states. Native RLC from scallop myofibrils was extracted and replaced completely with gizzard RLC labeled specifically at Cys 108 with erythrosin iodoacetamide (ErIA). The calcium sensitivity of the ATPase activity of the labeled myofibril preparation was quite similar to that of the native sample, indicating that the ErIA-labeled RLC is functionally bound to the myosin head. In rigor (in the absence of ATP, when all the myosin heads are rigidly bound to the thin filament), a slight decay was observed in the first few microseconds, followed by no change in the anisotropy. This indicates small-amplitude restricted motions of the RLC or the entire LC domain of myosin. Addition of calcium to rigor restricts these motions further. Relaxation with ATP (no Ca) causes a large decay in the anisotropy, indicating large-amplitude rotational motion with correlation times of 5-50 micros. Further addition of calcium, to induce contraction, resulted in a decrease in the rate and amplitude of anisotropy decay. In particular, there is clear evidence for a slow rotational motion with a correlation time of approximately 300 micros, which is not present either in rigor or relaxation. This indicates rotational motion that specifically correlates with force generation. The changes in the rotational dynamics of the light-chain domain in rigor, relaxation, and contraction support earlier work based on probes of the catalytic domain that muscle contraction is accompanied by a disorder-to-order transition of the myosin head. However, the motions of the LC domain are different from those of the catalytic domain, which indicates rotation of the two domains relative to each other.

Adenosine Triphosphatases↗

PubMed2001

Synthesis and characterization of phosphorescent cyclometalated iridium complexes.

The preparation, photophysics, and solid state structures of octahedral organometallic Ir complexes with several different cyclometalated ligands are reported. IrCl3.nH2O cleanly cyclometalates a number of different compounds (i.e., 2-phenylpyridine, 2-(p-tolyl)pyridine, benzoquinoline, 2-phenylbenzothiazole, 2-(1-naphthyl)benzothiazole, and 2-phenylquinoline), forming the corresponding chloride-bridged dimers, CwedgeN2Ir(mu-Cl)2IrCwedgeN2 (CwedgeNis a cyclometalated ligand) in good yield. These chloride-bridged dimers react with acetyl acetone (acacH) and other bidentate, monoanionic ligands such as picolinic acid (picH) and N-methylsalicylimine (salH), to give monomeric CwedgeN2Ir(LX) complexes (LX = acac, pic, sal). The emission spectra of these complexes are largely governed by the nature of the cyclometalating ligand, leading to lambda(max) values from 510 to 606 nm for the complexes reported here. The strong spin-orbit coupling of iridium mixes the formally forbidden 3MLCT and 3pi-pi* transitions with the allowed 1MLCT, leading to a strong phosphorescence with good quantum efficiencies (0.1-0.4) and room temperature lifetimes in the microsecond regime. The emission spectra of the CwedgeN2Ir(LX) complexes are surprisingly similar to the fac-IrCwedgeN3 complex of the same ligand, even though the structures of the two complexes are markedly different. The crystal structures of two of the CwedgeN2Ir(acac) complexes (i.e., CwedgeN = ppy and tpy) have been determined. Both complexes show cis-C,C', trans-N,N' disposition of the two cyclometalated ligands, similar to the structures reported for other complexes with a "CwedgeN2Ir" fragment. NMR data (1H and 13C) support a similar structure for all of the CwedgeN2Ir(LX) complexes. Close intermolecular contacts in both (ppy)2Ir(acac) and (tpy)2Ir(acac) lead to significantly red shifted emission spectra for crystalline samples of the ppy and tpy complexes relative to their solution spectra.

Journal Article↗

PubMed2003

Realizing green phosphorescent light-emitting materials from rhenium(i) pyrazolato diimine complexes.

Two neutral pyrazolato diimine rhenium(I) carbonyl complexes with formula [Re(CO)(3)(N-N)(btpz)] where N-N = 2,2'-bipyridine (1) and 1,10-phenanathroline (2), and btpz = 3,5-bis(trifluoromethyl) pyrazolate, were synthesized and characterized by elemental analysis, routine spectroscopic methods, and single-crystal X-ray diffraction study. Ground and excited state properties of these complexes were investigated by steady-state and time-resolved spectroscopies. Complexes 1 and 2 show photoluminescent emission in both solution and solid-state at room temperature, arising from metal to ligand charge-transfer (MLCT) transition with strong overlapping of intraligand pi --> pi transitions. The long-lived excited state lifetimes of complexes 1 and 2, which are on the order of microseconds, indicate the presence of phosphorescent emission. As these complexes hold the potential to serve as phosphors for organic light-emitting diodes (OLEDs), their electroluminescent performances were evaluated by employing them as dopants of various electron transport layer (ETL) or hole transport layer (HTL) hosts. For complex 1, a green electrophosphorescence emission centered at lambda(max) = 530 nm was observed at low turn-on voltage ( approximately 6 V) with luminous power efficiency of 0.72 lm/W, external quantum efficiency of 0.82%, and luminance of 2300 cd/m(2) at a current density of 100 mA/cm(2).

Journal Article↗

PubMed2003

Enhancement of the phosphorescence of organic luminophores upon interaction with a mercury trifunctional Lewis acid.

The interaction of the trinuclear mercury(II) complex [(o-C(6)F(4)Hg)(3)] (1) and pyrene leads to the formation of the 1:1 adduct 1.pyrene. The crystal structure of this adduct reveals the existence of supramolecular stacks in which molecules of 1 and molecules of pyrene alternate along the infinite chains. Steady-state and time-resolved photoluminescence measurements indicate the occurrence of a heavy atom effect which results in red, green, and blue (RGB) phosphorescent emissions for 1.pyrene, 1.naphthalene, and 1.biphenyl, respectively.

Journal Article↗

PubMed2005

Synthesis and characterization of phenanthrylphosphine gold complex: observation of Au-induced blue-green phosphorescence at room temperature.

A new 9-diphenylphosphinophenanthrene ligand (9DPP, 1), its oxide (9DPPO, 2), and its gold complex [(AuCl(9DPP)] (3) were synthesized. The Au(I) complex 3 was found to exhibit intense blue-green, room-temperature phosphorescence (Phip = 0.06 and tauT = 22.7 micros) originating in the locally excited triplet of the phenanthrene moiety (3LE) in degassed 2-methyltetrahydrofuran solution. On the assumption that PhiST = 1.0 for 3, the radiative rate constant (kr) in the triplet state is calculated to be 2.6 x 10(3) s(-1). This value is 4 orders of magnitude larger than the radiative rate constant of the triplet phenanthrene (0.26 s(-1)). Thus, the coordinated Au(I) atom is concluded to have a markedly large heavy-atom effect on kr of the phenanthrene chromophore in 3.

Journal Article↗

PubMed2005

New phosphorescent polynuclear Cu(I) compounds based on linear and star-shaped 2-(2'-pyridyl)benzimidazolyl derivatives: syntheses, structures, luminescence, and electroluminescence.

Four dinuclear and trinuclear Cu(I) complexes that contain 2-(2'-pyridyl)benzimidazolyl derivative ligands including 1,4-bis[2-(2'-pyridyl)benzimidazolyl]benzene (1,4-bmb), 1,3-bis[2-(2'-pyridyl)benzimidazolyl]benzene (1,3-bmb), 1,3,5-tris[2-(2'-pyridyl)benzimidazolyl]benzene (tmb), and 4,4'-bis[2-(2'-pyridyl)benzimidazolyl]biphenyl (bmbp) have been synthesized. The formulas of these complexes are [Cu(2)(1,4-bmb)(PPh(3))(4)][BF(4)](2) (1), [Cu(2)(1,3-bmb)(PPh(3))(4)][BF(4)](2) (2), [Cu(3)(tmb)(PPh(3))(6)][BF(4)](3) (3), and [Cu(2)(bmbp)(PPh(3))(4)][BF(4)](2) (4), respectively. The crystal structures of 2-4 have been determined by single-crystal X-ray diffraction analyses. The Cu(I) ions in the complexes have a distorted tetrahedral geometry. For 3, two structural isomers (syn and anti) resulted from two different orientations of the three 2-(2'-pyridyl)benzimidazolyl chelating units were observed in the crystal lattice. Variable-temperature (1)H NMR experiments established the presence of syn and anti isomers for 1-3 in solution which interconvert at ambient temperature. Complexes 1-4 have a weak MLCT absorption band in the 350-450 nm region and display a yellow-orange emission when irradiated by UV light. One unexpected finding is that the yellow-orange emission of complexes 1-4 has a very long decay lifetime (approximately 200 micros) at 77 K. An electroluminescent (EL) device using 4 as the emitter and PVK as the host was fabricated. However, the long decay lifetime of the copper complexes may limit their applications as phosphorescent emitters in EL devices.

Journal Article↗