Emission Spectra Research Articles

2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study

Many properties of 2,4-dichlorophenoxyacetic acid (2,4-D) depend on its molecular environment, such as whether it is an isolated molecule, a dimer, or in a crystalline state. The molecular geometry, conformational analysis, and vibrational spectrum of 2,4-D were theoretically calculated using Density Functional Theory (DFT) methods. A new slightly more stable conformer was found, which is different to those previously reported. The most stable conformer shows a dimer by means of hydrogen bonds between the carboxylic groups of both molecules, which agrees with the experimental results. The crystal structure of 2,4-D was also calculated with 3D periodical boundary conditions at the DFT level. From the theoretical IR spectra, a vibrational analysis of this molecular species was accomplished, and the bands were reassigned. 1H and 13C NMR in the dissolution and solid states, respectively, showed intramolecular hydrogen bonds between carboxylic acid groups. The dimer is more stable than the isolated molecule. All these results indicated that the dimer can also exist in the solid state, which could explain the low solubility of this compound. In addition, the intercalation of 2,4-D into the confined interlayer space of montmorillonite was also calculated, and it was found that the adsorption is energetically favourable. This result was experimentally confirmed. These findings predicted that these natural clay minerals, which are found in the environment, can be excellent adsorbents for the 2,4-D pollutant.

Exploring a metal/base-free porphyrin involving a carboxyl-functionalized pyridine moiety for photocatalytic N-arylation of benzamide validated using RSM.

A porphyrin comprising a carboxyl-functionalized pyridine moiety was synthesized and characterized using 1H NMR, 13C NMR, FT-IR, powder-XRD, BET, ICP-MS, SEM and EDAX. The proton level (H0 = 1.19) and energy band gap (1.39 eV) were determined via UV-Vis spectrophotometry. The UV-visible and fluorescence emission spectra indicated the absorption window of the porphyrin photocatalyst with a distinct Soret band at 424 nm and four Q-bands at 517, 558, 595, and 649 nm. The existence of four Q-bands, the powder XRD data and the ICP-MS analysis supported the absence of metal in the porphyrin photocatalyst. The best photocatalytic conditions generated using Box-Behnken design of RSM (0.2 mol% PcCFP, 5 W LED, 1 : 1.2 ArX : ArCONH2, 24 h) were confirmed through the model reaction of benzamide and 1-bromo-4-nitrobenzene. The N-arylation of benzamide was achieved in a custom-built photoreactor at ambient conditions under exposure to 5 W LED light. Different ArX compounds comprising electron-repelling and electron-attracting groups were assessed to test the potential of the photocatalyst. The porphyrin was found to exhibit significant catalytic activity for C-N bond formation, resulting in 21-73% yields of the substituted benzanilide products. The N-arylated benzamide formation was confirmed using 1H NMR, 13C NMR, HR-MS and SC-XRD. Additionally, heteroaryl halides such as 2-bromo-, 3-bromo-, and 4-bromo-pyridine, as well as 2-chloro-4-methylpyridine, were also found to be compatible and provided admirable yields (28-67%). The stability and heterogeneous nature of the porphyrin photocatalyst were confirmed using FT-IR. The stability of the photocatalyst after the sixth run was demonstrated by the slight decline in the yield of the product from 71 to 67%. The formation of an aryl radical was detected using the scavenger TEMPO, which led to the achievement of N-arylated benzamides containing intermediates of industrial drugs.

Updates on the molecular spectrum of MEFV variants in lebanese patients with Familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disorder, particularly present in the Mediterranean populations, and associated with pathogenic variants in the MEFV gene. This study aims to investigate the distribution of MEFV variants in a large cohort of Lebanese patients, and to explore the genotype-phenotype correlation among affected individuals. A retrospective analysis was conducted on 3,167 patients referred for MEFV sequencing at the Medical Genetics and Genomics Center(CGGM) at Saint-Joseph University of Beirut-Lebanon, from 2006 to 2023. Sanger sequencing was used to detect MEFV variants, focusing initially on hot-spot exons. Among the 3,167 patients, 46.73% (N = 1,480) carried at least one MEFV variant. The most common variants detected were M694V and V726A, both found in 28.98% of cases, followed by E148Q(27.83%) and M694I(13.98%). Moreover, Shiites and Sunni Muslims, and individuals from South and North Lebanon exhibited the highest frequency of variants. Interestingly, family history was found to be significantly higher in patients having two MEFV variants than those with one variant (p = 0.0026). The most commonly reported symptoms were fever(78%), abdominal pain(88%), joint pain(65%), and thoracic pain(46%). The genotype-phenotype correlation analysis revealed a more severe phenotype in patients carrying the M694V or V726A mutations compared to those with the homozygous E148Q genotype. This study, the largest in Lebanon, highlights the high prevalence of MEFV variants, particularly M694V and V726A, in FMF patients. Our data provide valuable insights into the genetic landscape of FMF in Lebanon and emphasize the importance of early genetic screening for a better disease management and genetic counselling.

Impact of Soil Use On Winter Greenhouse Gas Emissions: The Agricultural Sector in Alagoas Through An Emissions Inventory

Objective: To prepare a greenhouse gas inventory within the state of Alagoas for 2019, using data and factors from livestock and agriculture. Theoretical framework: Preparing an inventory is an important tool for understanding climate change that is directly related to greenhouse gas (GHG) emissions, mostly resulting from anthropogenic activities. In Brazil, agriculture stands out as one of the main sources of emissions, driven by the production of grains and animals for domestic and foreign consumption. Due to the difficulty of direct measurement, emissions are often assessed through inventories. The GHG emissions inventory is one of the basic tools that provides relevant data to direct certain public policies, or civil society actions, to reduce GHG emissions into the atmosphere, given that the state of Alagoas has few scientific productions on GHG sources and emissions. Methodology: Emissions were calculated by multiplying the emission coefficient following the methodology proposed by the IPCC, GHG Protocol, using the multiplication of the emission coefficient also indicated by the IPCC, MCTIC, EMBRAPA by the total number of heads or by the number of hectares of each crop in 2019 to calculate emissions. The results were then transformed into figures to facilitate understanding and analysis. Results and Discussions: N2O emissions from temporary and permanent crops, and N2O and CH4 emissions from flooded rice crops; as well as CH4 and N2O emissions from the livestock sector, totaling 10.53 MtCO2e of emissions in 2019. Comparing with other results, differences were noted in the total emissions due to the adoption of different methodologies and factors, as well as in what to measure, so this article presents advances and limitations, contributing to a greater depth of understanding of emissions. Research Implications: This research contributes to the scientific literature, public policy actions and environmental planning, as well as understanding and analyzing the impacts on the agricultural sector, and methodological and scientific advances, and the promotion of new research and data updates that can guide new research and updates. Originality/value: This study provides a regional focus on Alagoas, with consistent applications of international methodologies (IPCC, GHG Protocol) in local contexts. It serves as a basis for local public policies, environmental and climate impacts, expanding knowledge about the state's emissions, and encouraging innovation in local methods, as well as awareness and social mobilization.

Green Assessment of Sensitive Spectrofluorimetric Methods for Simultaneous Estimation of Formoterol Fumarate and Fluticasone Propionate Using a Micelle-Mediated Approach.

Highly sensitive spectrofluorimetric methods were developed for the quantitative estimation of formoterol fumarate dihydrate (FFD) and fluticasone propionate (FP) in both authentic raw materials and marketed dosage forms using a micellar-enhanced spectrofluorimetric approach. The proposed methods are based on the determination of FP in the presence of FFD using the first derivative emission spectrofluorimetry. The peak amplitude of the emission spectra of the formed micellar fluorescence was measured at 465nm after excitation at 236nm (λ max of FP).The second method quantifies FFD in the presence of FP using second derivative emission spectrofluorimetry. This method measures the peak amplitude of the emission spectra of the formed micelle at 283nm, where there is no interference from FP, following excitation at 214nm. In these methods, the emission spectra of the target drugs are measured after micellar formation, with excitation wavelengths at 214nm for FFD and 236nm for FP. The fluorescence intensity was enhanced using β-cyclodextrin as a micellar system after optimizing parameters affecting native fluorescence, such as diluting solvents, surfactants, and varying concentrations of β-cyclodextrin. A linear relationship was observed between the fluorescence intensity and concentration for FP over the range of 50-100ng/mL and for FFD over the range of 30-700ng/mL. The developed methods are simple, sensitive, non-extractive, economical, and suitable for routine analysis of FFD and FP in their raw materials and combined marketed dosage forms. The proposed techniques were carefully validated for linearity, accuracy, precision, and specificity according to the International Council for Harmonization (ICH) guidelines, demonstrating high sensitivity with lower limits of detection and quantitation. Additionally, the analytical greenness of the suggested procedures was assessed using the Analytical Greenness Metric Approach (AGREE), the Red-Green-Blue model, and the Green Procedure Analytical Index (GAPI).

Confocal Laser Scanning Microscopy as a Method for Identifying Variation in Puparial Morphology and Establishing Characters for Taxonomic Determination

Calliphoridae, or blow flies, are of much ecological and practical importance given their roles in decompositional ecology, medical and veterinary myiasis, and forensic entomology. As ephemeral and rapidly developing species, adults are frequently not present for identification, but puparia (the remaining outer integument of the third instar larvae) are frequently found. These heavily sclerotized remains are stable in the environment but they are of a conservative character. Historically, scanning electron microscopy (SEM) has been used for characterization, a technique which is not only time-consuming but also often expensive, effectively making large numbers of specimens impossible to quantify. As an alternative, confocal laser scanning laser microscopy (CSLM) was tested for utility in providing superior data over SEM. Furthermore, due to the use of intrinsic autofluorescence for imagining, CSLM is significantly more rapid than SEM, requiring no preparation for imaging. Three channels of excitation and emission spectra provided not only image data from the pupal wall but also from the hydrocarbons found upon the puparia. The excitation wavelengths were 404.7, 488, and 640.5 nm, and the emissions were 425–475, 500–550, and 663–738 nm. For ten species of calliphorids, CSLM was used to image puparia. Not only did this provide characters for species identification but it also allowed for the examination of hundreds of specimens.

Energy-resolved pulse profile changes in V 0332+53: Indications of wings in the cyclotron absorption line profile

We aim to investigate the energy-resolved pulse profile changes of the accreting X-ray pulsar focusing in the cyclotron line energy range, using the full set of available observations. We applied a tailored pipeline to study the energy dependence of the pulse profiles and to build the pulsed fraction spectra (PFS) for the different observations. We also studied the profile changes using cross-correlation and lag spectra. We re-analysed the energy spectra to search for links between the local features observed in the PFS and spectral emission components associated with the shape of the fundamental cyclotron line. In the PFS data, with sufficiently high statistics, we observe a consistent behaviour around the cyclotron line energy. Specifically, two Gaussian-shaped features appear symmetrically on either side of the putative cyclotron line. These features exhibit minimal variation with source luminosity, and their peak positions consistently remain on the left and right of the cyclotron line energy. Associated with the cyclotron line-forming region, we interpret them as evidence for the resonant cyclotron absorption line wings, as predicted by theoretical models of how the cyclotron line profile should appear along the observer's line of sight. A phase-resolved analysis of the pulse in the energy bands surrounding these features enables us to determine both the spectral shape and the intensity of the photons responsible for these peaks in the PFS. Assuming these features correspond to a spectral component, we used their shapes as priors for the corresponding emission components, finding a statistically satisfactory description of the spectra. To explain these results, we propose that our line of sight is close to the direction of the spin axis, while the magnetic axis is likely orthogonal to it.

Asymmetric Donor–Acceptor 2,7-Disubstituted Fluorenes and Their 9-Diazoderivatives: Synthesis, Optical Spectra and Photolysis

In a search for dyes photoactivatable with visible light, fluorenes with substituents at positions 2 and 7 were prepared, and their absorption and emission spectra were studied. In particular, the synthesis route to 9-diazofluorenes with 2-(N,N-dialkylamino) and N-modified 7-(4-pyridyl) substituents was established. These compounds are initially non-fluorescent, undergo photolysis with UV or blue light, and—in non-polar media—provide orange- to red-emitting products with a large separation between absorption and emission bands. Irradiation of non-fluorescent 9-diazoderivative 20 in dioxane with the light of 365 nm or 470 nm was accompanied by strong fluorescence gain (10 to 20 times), orange–red emission, and a large Stokes shift of photoproducts, which structurally relate to fluorescent betaine 13 (model compound without diazo group). Photolysis of 20 in protic solvents (ROH = MeOH, H2O) provided clean transformation to C9-OR derivatives, though the emission gain in protic solvents was low.

A theoretical investigation of spectroscopy properties and transition properties of TlBr+ cation

The potential energy curves, dipole moments and transition dipole moments of the 14 Λ–S states and 30 Ω states of TlBr+ cation were performed using the multi-reference configuration interaction method. The Davidson correction and spin–orbit coupling effects were also considered. The spectroscopic properties and transition properties of TlBr+ cation were reported at the first time. The results show that the X2Π is the ground state and the A2Σ+ is the first excited state, which are both weakly bound states. 14 Λ–S states are all electronically bound except for the 24Π state, which is repulsive. The phenomenon of avoided crossing in the Ω states occurs in the energy region between 30,000 and 50,000 cm−1. The Franck–Condon factors, radiative lifetimes and emission coefficients between the and transitions are both calculated. The results indicated that the radiative lifetimes of the and states are too large to laser cooling TlBr+ cation, laser cooling of TlBr+ cation is not feasible. These results provide a theoretical basis to explore the spectroscopic properties of TlBr+ cation.

Dual- and quad-FSF laser optical frequency comb application for time delay variation associated measurements

The frequency-shifted feedback (FSF) laser is an optoelectronic system with an optical feedback loop with a characteristic feature that consists of a broadband optical emission spectrum that does not contain modes. Nevertheless, this system may operate in the so-called mode-locking regime, when the output optical signal is a sequence of short optical pulses with a repetition rate determined by the delay time in the feedback loop. In the frequency domain such a sequence forms the optical frequency comb with line spacing defined by time delay magnitude. It was shown recently that the sequential frequency down-conversion technique allows us to obtain tunable dual- and quad-combs when the FSF laser is seeded only with optical amplifier spontaneous emission. We propose to apply these combs to fulfill measurements associated with time delay variation, such as distance ranging and optical material refraction coefficient measurements.

A novel dynamic vibration absorber for vibration control of piping systems under multi-frequency harmonic excitations

To suppress the significant vibration line spectra of piping systems under multi-frequency harmonic excitations, a novel dynamic vibration absorber (NDVA) is designed. The NDVA integrates numerous independent resonant units within a finite space through an ingenious structural design and possesses rich frequency regulation characteristics. A vibration model of the piping system equipped with the NDVA is established, and the approximate equivalent parameters of both the piping and the resonant units are inverted based on the frequency response function (FRF) test results. These parameters can be substituted into the model to enhance the accuracy and validity of the theoretical calculations. Based on the relationship between the absorbing bandwidth of the NDVA and the intervals of multi-frequency excitation frequencies, a tailored regulation strategy for different densities of excitation frequencies is proposed. Subsequently, the multi-frequency vibration reduction capability of the NDVA is verified through an example involving dual-frequency harmonic excitations. When there is a notable difference in the intensities of the multi-frequency vibration line spectra, a genetic algorithm is utilized to optimize the mass allocation of the resonant units. Simulation and test results demonstrate that the maximum response amplitude of the optimized system is further reduced.

A Vibration Signal-Based Active Noise Control Method for Liquid-Filled Pipelines

Pulsation noise in the piping system generated by the excitation of the pump source seriously affects the reliability of the pipeline system and mechanical equipment. The active noise control can effectively suppress the low-frequency noise in the liquid-filled pipeline. Active control methods with intrusive secondary sources generally use dynamic pressure sensors or hydrophones to collect signals, which destroy the structure of the pipe. In this paper, we propose an active noise control method utilizing signals acquired by accelerometers, which adopts offline modeling of the secondary path and the notch narrowband FxLMS algorithm for controlling the secondary source actuation. The feasibility of this method is verified by LabVIEW simulation and active noise control test of the liquid-filled pipeline. The test results show that this method can achieve more than 4 dB reduction for low-frequency (10~200 Hz) line spectrum noise under most operating conditions.

Clinical, Pathologic, and Molecular spectrum of Angioinmmunoblastic T-cell Lymphoma Cutaneous Lesions: Clinical, Pathologic, and Molecular Analysis.

Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive malignancy that frequently presents with extranodal involvement. Cutaneous tropism is clinically and histopathologically variable, which may pose a diagnostic challenge. We conducted a retrospective analysis of 40 samples of 20 cases of cutaneous AITL, focusing on the clinicopathologic and molecular correlations between skin and lymph node (LN) samples. In all cases, cutaneous involvement was concurrent with or followed the diagnosis of nodal AITL, with no cases preceding systemic involvement. Clinically, cutaneous AITL presented in 2 main forms: an evanescent rash and persistent lesions, with histopathology revealing diverse infiltration patterns, including perivascular, nodular, granulomatous, panniculitic, vasculitis, and epidermotropic. Clinical presentation and histologic patterns tend to correlate. Histopathologically, plasma cells were present in 15/22 skin samples, 5 of them being kappa-light restricted but polytypic in corresponding LNs. Epstein-Barr virus+ B cells were present in 10 cutaneous lesions and were already present in corresponding LNs. Molecular studies found correlations in all but one case between LN and skin, particularly in the presence of RHOA and TET2 mutations, which were identified in 8 of 12 cases. Molecular analysis was also informative in 4 cases with low levels of infiltration. The study also highlighted unique cases with distinct clinical and histopathologic patterns coexisting in the same patient over time. One case exhibited simultaneous granulomatous and epidermotropic patterns in different skin lesions. Four cases of cutaneous B-cell lymphomas associated with AITL were identified. Our study underscores the importance of integrating clinical, histopathologic, and molecular data to accurately diagnose cutaneous AITL.

Flexible Site-Specific Labeling-Mediated Self-Assembly Sensor Based on Quantum Dots and LUMinescent AntiBody Sensor for Duplexed Detection of Antibodies.

Over recent years, the LUMinescent AntiBody Sensor (LUMABS) system, utilizing bioluminescence resonance energy transfer (BRET), has emerged as a highly effective method for antibody detection. This system incorporates NanoLuc (Nluc) as the donor and fluorescent protein (FP) as the acceptor. However, the limited Stokes shift of FP poses a challenge, as it leads to significant spectral cross-talk between the excitation and emission spectra. This issue complicates the implementation of multiplexed detection. To address this challenge, we present an innovative enhancement to the LUMABS sensor with quantum dots (QDs) as the acceptor instead of FP. The use of QDs offers several advantages over those of traditional FP-based sensors. The biotin-avidin system facilitates the flexible interchangeability of QDs, allowing for a more convenient multicolor sensor construct. The new QD-LUMABS system overcomes the limitations of spectral cross-talk and provides better spectral separation. This breakthrough enables the successful implementation of multiplexed detection for multiple targets simultaneously. Results demonstrated that the wavelength-tunable QD-LUMABS sensors achieved picomolar-level detection limits for antibodies and that this sensor-construction strategy was generally applicable among various epitopes and their antibodies. Furthermore, this sensor displayed excellent duplexing capabilities. These features underscore its potential for future clinical disease diagnosis applications.

Angular dependence of random laser emission by using ZnO-CuO heterostructure as scatterer and its applications in biocompatible imaging.

The angular dependence of random laser (RL) generation in a commercially available rhodamine 6G (Rh6G) dye has been demonstrated using ZnO-CuO heterostructure as passive scatterers. The grass-like superstructure formed at a 1M:1M molar ratio of ZnO-CuO significantly enhances scattering, resulting in RL spikes with a full width at half maximum (FWHM) of just a few nanometer and a noticeable reduction in the RL threshold. RL emission spectra were collected over an angular spread of 0-180 degrees, revealing a remarkable shift in RL emission from 566nm to 580nm. Additionally, we explored RL using a biological extract from Caesalpinia sappan L (Biancaeasappan L) and demonstrated speckle-free imaging with an affordable handheld microscope called the Foldscope. The biocompatibility of the wood extract shows significant potential for applications in speckle-free imaging. We had assessed the Pearson correlation coefficient between images captured under LED, RL, and conventional laser illumination. It is observed that the value of the coefficient becomes the lowest under RL illumination which confirms the formation of high-resolution and artifact-free images.

Delocalized Nonbonding Orbitals of Thioxanthone in Polycyclic Aromatic Hydrocarbons for Reduced Energy Gap and Narrowband Emission.

Chalcogen-containing carbonyls, specifically thioxanthone (TX), hold great potential in organic light-emitting diodes (OLEDs). While the development of narrowband OLEDs with chalcogen-containing carbonyls remains challenging due to difficulties in achieving both high device efficiency and narrow emission spectra. Herein, via a strategic incorporation of the TX moiety, two orange-red narrowband emitters, 2TXBN and BNTXBN, are designed and synthesized for the first time. Both 2TXBN and BNTXBN exhibit bright orange-red emissions with peaks at 582 and 585 nm, respectively, along with narrow full widths at half maximum of 30 and 32 nm. Notably, 2TXBN demonstrates delocalization of the nonbonding orbital within the TX segment, which raises the first triplet energy level and reduces the singlet-triplet energy gap. This electronic structural adjustment effectively shortens the delayed fluorescence lifetime, leading to enhanced device performance. Accordingly, OLED employing 2TXBN as the emitter achieves remarkable performance, with a maximum external quantum efficiency of 31.0%, a current efficiency of 69.0 cd A-1, and a power efficiency of 76.0 lm W-1, highlighting the efficacy of the nonbonding orbital delocalization strategy in achieving bathochromic-shifted narrowband OLED materials.

Transition of Food Consumption Patterns and Carbon Footprint of Urban and Rural Residents in China

The food system is an important source of greenhouse gas emissions, and the carbon footprint analysis of food consumption under the dual carbon background is of great significance for the sustainable development of the food system. To reveal the differences in food consumption patterns and carbon footprints between urban and rural residents in China, the life cycle carbon emission coefficient method was used to measure the direct carbon emissions of food consumption by urban and rural residents in China from 2000 to 2021. From the perspective of carbon footprint composition, the following main conclusions were drawn： ① The structure of food consumption among residents in China shifted from predominantly plant-based to a balanced consumption of both plant- and animal-based foods, reducing the disparity in various food consumption quantities between urban and rural residents. ② The per capita carbon footprint from food consumption among Chinese residents exhibited an overall increasing trend from 2000 to 2021, with an average annual growth rate of 1.4%. Grain consumption contributed the most to the carbon footprint （22.2%）. ③ Currently, urban residents in China demonstrate significantly higher food consumption carbon footprints compared to those of rural residents, and this trend is continuously rising. In urban areas, the carbon footprint of plant-based foods was increasing at a higher rate than that of animal-based foods, while the opposite trend was observed in rural areas. ④ Factors such as per capita disposable income, per capita GDP, Engel coefficient, population structure, and various food consumption carbon footprints, as well as per capita food consumption carbon footprints, exhibited significant correlations. Here, we conducted a comprehensive study on the eating habits of urban and rural residents in China, along with the carbon emissions associated with their food consumption, which offer valuable insights that can guide sustainable food consumption practices among Chinese residents and contribute to the achievement of carbon neutrality in the food industry.

Expanding the Molecular Spectrum of MMP21 Missense Variants: Clinical Insights and Literature Review

Expanding the Molecular Spectrum of MMP21 Missense Variants: Clinical Insights and Literature Review

Symmetry Breaking of FeN4 Moiety via Edge Defects for Acidic Oxygen Reduction Reaction.

Fe-N-C catalysts, with a planar D4h symmetric FeN4 structure, show promising as noble metal-free oxygen reduction reaction catalysts. Nonetheless, the highly symmetric structure restricts the effective manipulation of its geometric and electronic structures, impeding further enhancements in oxygen reduction reaction performance. Here, a high proportion of asymmetric edge-carbon was successfully introduced into Fe-N-C catalysts through morphology engineering, enabling the precise modulation of the FeN4 active site. Electrochemical experimental results demonstrate that FeN4@porous carbon (FeN4@PC), featuring enriched asymmetric edge-FeN4 active sites, exhibits higher acidic oxygen reduction reaction catalytic activity compared to FeN4@flaky carbon (FeN4@FC), where symmetric FeN4 is primarily distributed within the basal-plane. Synchrotron X-ray absorption spectra, X-ray emission spectra, and theoretical calculations indicate that the enhanced oxygen reduction reaction catalytic activity of FeN4@PC is attributed to the higher oxidation state of Fe species in the edge structure of FeN4@PC. This finding paves the way for controlling the local geometric and electronic structures of single-atom active sites, leading to the development of novel and efficient Fe-N-C catalysts.

Enhanced Red Luminescence in Dy3+/Eu3+Co-doped Calcium Alumino Borosilicate Glasses for w-LED Applications.

Dy3+ and Eu3+ co-doped borosilicate glasses have been synthesised via melt quench technique. Amorphous behaviour of the sample has been verified by XRD study. FT-IR analysis confirmed the presence of various bonds in the host lattice. Energy band gap values of the co-doped glasses were estimated from the UV-VIS data via Tauc Plot. Excitation spectra were recorded under 575nm (Dy3+) and 612nm (Eu3+) emission wavelengths of co-doped glasses. Emission spectra of the co-doped glasses under 350nm and 393nm showed a significant shift towards increasing red emission with increasing Eu3+ concentrations. Dexter's theory was applied to study the transfer of energy mechanism between Dy3+ and Eu3+ ions. Time decay curves were plotted for the co-doped glasses for 350nm excitation and 576nm emission wavelength. CIE coordinate diagram shows a shift towards red region with increasing excitation wavelength from 350nm to 465nm. The enhancement of red component with increasing Eu3+ concentrations in the as -prepared borosilicate glasses can be appropriately utilised in various w-LEDs and other optoelectronic devices applications.