Molecular mechanism of distinct chemokine engagement and functional divergence of the human Duffy antigen receptor.

The Duffy antigen receptor is a seven-transmembrane (7TM) protein expressed primarily at the surface of red blood cells and displays strikingly promiscuous binding to multiple inflammatory and homeostatic chemokines. It serves as the basis of the Duffy blood group system in humans and also acts as the primary attachment site for malarial parasite Plasmodium vivax and pore-forming toxins secreted by Staphylococcus aureus. Here, we comprehensively profile transducer coupling of this receptor, discover potential non-canonical signaling pathways, and determine the cryoelectron microscopy (cryo-EM) structure in complex with the chemokine CCL7. The structure reveals a distinct binding mode of chemokines, as reflected by relatively superficial binding and a partially formed orthosteric binding pocket. We also observe a dramatic shortening of TM5 and 6 on the intracellular side, which precludes the formation of the docking site for canonical signal transducers, thereby providing a possible explanation for the distinct pharmacological and functional phenotype of this receptor.

A SIRT7-dependent acetylation switch regulates early B cell differentiation and lineage commitment through Pax5.

B lymphopoiesis is orchestrated by lineage-specific transcription factors. In B cell progenitors, lineage commitment is mediated by Pax5, which is commonly mutated in B cell acute lymphoblastic leukemia. Despite its essential role in immunity, the mechanisms regulating Pax5 function remain largely unknown. Here, we found that the NAD+-dependent enzyme SIRT7 coordinates B cell development through deacetylation of Pax5 at K198, which promotes Pax5 protein stability and transcriptional activity. Neither Pax5K198 deacetylated nor acetylated mimics rescued B cell differentiation in Pax5-/- pro-B cells, suggesting that B cell development requires Pax5 dynamic deacetylation. The Pax5K198 deacetylation mimic restored lineage commitment in Pax5-/- pro-B cells and B cell differentiation in Sirt7-/- pro-B cells, suggesting the uncoupling of differentiation from lineage commitment. The SIRT7-Pax5 interplay was conserved in B cell acute lymphoblastic leukemia, where SIRT7 expression correlated with good prognosis. Our findings reveal a crucial mechanism for B lymphopoiesis and highlight the relevance of sirtuins in immune function.

Biogenesis and Functionality of Sortase-Assembled Pili in Gram-Positive Bacteria.

A unique class of multimeric proteins made of covalently linked subunits known as pili, or fimbriae, are assembled and displayed on the gram-positive bacterial cell surface by a conserved transpeptidase enzyme named pilus-specific sortase. Sortase-assembled pili are produced by a wide range of gram-positive commensal and pathogenic bacteria inhabiting diverse niches such as the human oral cavity, gut, urogenital tract, and skin. These surface appendages serve many functions, such as molecular adhesins, immunomodulators, and virulence determinants, that significantly contribute to both the commensal and pathogenic attributes of producer microbes. Intensive genetic, biochemical, physiological, and structural studies have been devoted to unveiling the assembly mechanism and functions, as well as the utility of these proteins in vaccine development and other biotechnological applications. We provide a comprehensive review of these topics and discuss the current status and future prospects of the field.

SIRT7 promotes lung cancer progression by destabilizing the tumor suppressor ARF.

Sirtuin 7 (SIRT7) is a member of the mammalian family of nicotinamide adenine dinucleotide (NAD+)-dependent histone/protein deacetylases, known as sirtuins. It acts as a potent oncogene in numerous malignancies, but the molecular mechanisms employed by SIRT7 to sustain lung cancer progression remain largely uncharacterized. We demonstrate that SIRT7 exerts oncogenic functions in lung cancer cells by destabilizing the tumor suppressor alternative reading frame (ARF). SIRT7 directly interacts with ARF and prevents binding of ARF to nucleophosmin, thereby promoting proteasomal-dependent degradation of ARF. We show that SIRT7-mediated degradation of ARF increases expression of protumorigenic genes and stimulates proliferation of non-small-cell lung cancer (NSCLC) cells both in vitro and in vivo in a mouse xenograft model. Bioinformatics analysis of transcriptome data from human lung adenocarcinomas revealed a correlation between SIRT7 expression and increased activity of genes normally repressed by ARF. We propose that disruption of SIRT7-ARF signaling stabilizes ARF and thus attenuates cancer cell proliferation, offering a strategy to mitigate NSCLC progression.

Europium-based ß-hydroxyketone complexes: synthesis, optoelectronic, thermal and computational analyses.

Six red-light-emitting Eu(III) complexes having a ß-hydroxyketone as ligand and heterocyclic ring containing compounds as ancillary ligands were synthesized to explore their use in displays and optoelectronics. The coordinating behavior of complexes was determined by various techniques such as FTIR (Fourier transform infrared), 1H-NMR (Nuclear magnetic resonance), and 13C-NMR that establishes a bonding of ligand and ancillary ligand with the Eu(III) ion. Morphology and purity were investigated through XRD (X-ray diffraction), SEM (scanning electron microscopy) and EDS (energy-dispersive X-ray spectroscopy) analyses that suggest semicrystalline and pure complex formation. Thermal analysis of complexes by TGA/DTG (thermogravimetric/derivative thermogravimetric) indicates that complexes are stable upto 200 ºC temperature making them suitable for use in display devices. Analysis of the photophysical properties was carried out in both solid and solution states using PL (photoluminescence) studies, color parameters, J-O (Judd-Ofelt) analysis and bandgap. Most emissive transition (5D0 → 7F2) is responsible for the red emission in the complexes. The CIE (Commission International de I'Eclairage) coordinates of complexes also indicate the red emission on UV excitation. The bandgap which was obtained in the range of 2.54-3.02 eV reveals the semiconducting behavior of complexes. Values of J-O parameters and Ω2 in the complexes reflect asymmetric chemical environment around Eu (III) and less covalence and the Ω4 indicates that complexes are less rigid. Bandgap calculated through DFT (density function theory) for complexes is in range of 2.37-2.77 eV, and intensity parameters (J-O), energy transfer rates, and spherical coordinates were determined by LUMPAC software. The computational data are in good harmony with the experimental data. Further biological aspects of complexes were studied using antioxidant and antimicrobial studies.

Hijacking of the methylglyoxal detoxification pathway: a new tactic of Xoo pathogenesis in rice.

Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial blight (BB), has developed a unique strategy to infect rice by hijacking the host's methylglyoxal (MG) detoxification pathway. This results in an over-accumulation of MG, which facilitates tissue colonization and evasion of host's immune responses. While MG role in abiotic stresses is well-documented, its involvement in biotic stresses has not been extensively explored. Recently, Fu et al. (2024) provided the first evidence of MG role in promoting Xoo pathogenesis in rice. This new virulence strategy contributes to the pathogen's remarkable adaptability and survival. In this mechanism of hijacking of MG detoxification pathway, Xoo induces OsWRKY62.1 to inhibit OsGLY II expression, leading to MG overaccumulation in infected rice cells. This excess MG hinders plant cell organelle function, creating a favorable environment for Xoo by compromising the rice defense system. In this article, we have presented our perspectives on how the BB pathogen adapts its virulence mechanisms to infect and cause disease in rice.

Study of Luminescence Phenomena of Tb (III) Containing Fluroquinoline for Application in Optoelectronic Devices.

This study presents a series of six vivid green Tb(III) complexes, denoted by the general formula [Tb(L)3.secondary sensitizers], where L represents 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-4-oxoquinoline-3-carboxylic acid and secondary sensitizers consist of heterocyclic N-donor aromatic systems. The synthesis of these complexes were achieved through a solvent-assisted grinding method, and their characterization involved various techniques such as CHN analysis, FTIR, NMR, UV, XRD, and NIR spectroscopy. These analyses confirmed the successful synthesis of complexes with coordination between the quinoline moiety and the metal ion. Photoluminescence studies were conducted in solid and solution phases, revealing excellent luminescence properties. The bright green color emitted by the complexes upon exposure to UV rays was attributed to the hypersensitive 5D4 → 7F5 transition. J-O analysis indicated an asymmetrical coordination environment around in the complexes. Additionally, various radiative properties (Ared, Anred, η, ßexp, σs) and band gap values were determined, highlighting the potential applications of these complexes in diverse optoelectronic fields. Chromaticity evaluation demonstrated high color purity in both solid and solution phases. Furthermore, the CCT value identified the solid complexes as a cool light source. Overall, the analyses supported the exceptional luminosity of synthesized complexes, positioning them as promising luminescent materials for a wide range of devices.

Preparation and Judd-Ofelt Analysis of Warm Red Luminescent Eu3+ Complexes for Semiconductor Lasing Devices.

Six novel red photoluminescent Eu3+ complexes with 3-formyl chromone as the primary sensitizer (L) were synthesized using the solution precipitation method. These complexes are [Eu(L3).X] where X is 2H2O (C1), phen (C2), neo (C3), bipy (C4), dmph (C5), and biquno (C6). These complexes were characterized by elemental analysis, EDAX analysis, SEM, FT-IR, thermo-gravimetric analysis (TGA/DTA) and photoluminescence spectra. The transition rates, quantum efficiency, and J-O intensity parameters were calculated using emission data and luminescence decay time (τ). Complexes exhibit a strong emission peak (5D0 → 7F2) of the Eu3+ ion in their luminescence emission spectra in solid and solution states, making them an effective emitter of the red color in OLEDs. The branching ratio of these complexes ranges from 80.67-82.92 in solid and 50.53-62.65 in solution state; CIE color coordinate of complexes falls in the red region. The color purity ranges [CP(%)] values for solid 95.26-97.27% and for solution ranges 85.11-93.43%. Correlated color temperature (CCT) of the complexes (C1-C6) ranged from 2710 to 3049 K in the solid state and 1775 to 2450 K in the solution state. These complexes are promising red emitters in OLEDs, semiconductors, and leasing devices.

Lipase domain effector AGLIP1 in Rhizoctonia solani triggers necrotic killing in plants.

KEY MESSAGE: We highlight the emerging role of the R. solani novel lipase domain effector AGLIP1 in suppressing pattern-triggered immunity and inducing plant cell death. The dynamic interplay between plants and Rhizoctonia solani constitutes a multifaceted struggle for survival and dominance. Within this complex dynamic, R. solani has evolved virulence mechanisms by secreting effectors that disrupt plants' first line of defense. A newly discovered effector, AGLIP1 in R. solani, plays a pivotal role in inducing plant cell death and subverting immune responses. AGLIP1, a protein containing a signal peptide and a lipase domain, involves complex formation in the intercellular space, followed by translocation to the plant cytoplasm, where it induces cell death (CD) and suppresses defense gene regulation. This study provides valuable insights into the intricate molecular interactions between plants and necrotrophic fungi, underscoring the imperative for further exploration in this field.

Prevalence, risk factors and effect of curative parathyroidectomy on nephrocalcinosis in Asian-Indian patients with symptomatic primary hyperparathyroidism.

Primary hyperparathyroidism (PHPT) is characterized by inappropriate secretion of parathyroid hormone, causing hypercalcemia and hypercalciuria, leading to renal stone diseases and nephrocalcinosis. The frequency, risk factors, and curative effect on nephrocalcinosis in post-parathyroidectomy have not been identified yet. Therefore, the present study evaluated the clinico-biochemical, radiological parameters and curative effect on nephrocalcinosis. A total of 583 PHPT patients were analysed in four groups viz. Group 1 (PHPT with nephrocalcinosis-98; 16.8%); Group 2 (PHPT with nephrolithiasis-227; 38.9%); Group 3 (PHPT with both nephrolithiasis and nephrocalcinosis-59; 10.1%); and Group 4 (PHPT without renal diseases-199, 34.1%). In the sub-group analysis, younger age (p ≤ 0.05), male gender (p ≤ 0.05), and hematuria (p ≤ 0.005) were significant in Group 1 vs. Group 4. Dysuria and low eGFR were significant in Group 1 vs. Group 2 (p ≤ 0.0005; p ≤ 0.05) and Group 1 vs. Group 4 (p ≤ 0.0005; p ≤ 0.0005). Polyuria (p ≤ 0.05; p ≤ 0.05, p ≤ 0.005), and gravluria (p ≤ 0.05; p ≤ 0.0005, p ≤ 0.005) were frequent in Group 1 vs. other groups. A significant difference was observed in S.Ca and, 24-hrs U.Ca in Group 1 vs. Group 2 {(12.2 (10.8-13.4) vs. 11.2 (10.7-12.4), p ≤ 0.05; 301 (189.5-465) vs. 180 (92.5-323.1), p ≤ 0.05} and Group 1 vs. Group 4 {(12.2 (10.8-13.4) vs. 11.4 (10.7-12.5), p ≤ 0.05 ; 301 (189.5-465) vs. 213 (110-360), p ≤ 0.0005}. Multivariate logistic regression showed gravluria [aOR = 9.2, p = 0.0001], S.Ca (aOR = 1.30, p = 0.003) and, 24-hrs U.Ca (aOR = 1.02, p = 0.042) to be independent predictors of nephrocalcinosis. Pre and post-operative assessment revealed decreased S. Ca levels [(11.9 ± 1.9) vs. (10.5 ± 1.0) mg/dL; p = 0.04] and complete radiological resolution (10.4%) in PHPT with nephrocalcinosis. Therefore, serum calcium, 24-hrs Urinary calcium, and gravluria were independent predictors of nephrocalcinosis with 10.4% showing complete radiological resolution post-operatively.

Holliday junction resolution by At-HIGLE: an SLX1 lineage endonuclease from Arabidopsis thaliana with a novel in-built regulatory mechanism.

Holliday junction is the key homologous recombination intermediate, resolved by structure-selective endonucleases (SSEs). SLX1 is the most promiscuous SSE of the GIY-YIG nuclease superfamily. In fungi and animals, SLX1 nuclease activity relies on a non-enzymatic partner, SLX4, but no SLX1-SLX4 like complex has ever been characterized in plants. Plants exhibit specialized DNA repair and recombination machinery. Based on sequence similarity with the GIY-YIG nuclease domain of SLX1 proteins from fungi and animals, At-HIGLE was identified to be a possible SLX1 like nuclease from plants. Here, we elucidated the crystal structure of the At-HIGLE nuclease domain from Arabidopsis thaliana, establishing it as a member of the SLX1-lineage of the GIY-YIG superfamily with structural changes in DNA interacting regions. We show that At-HIGLE can process branched-DNA molecules without an SLX4 like protein. Unlike fungal SLX1, At-HIGLE exists as a catalytically active homodimer capable of generating two coordinated nicks during HJ resolution. Truncating the extended C-terminal region of At-HIGLE increases its catalytic activity, changes the nicking pattern, and monomerizes At-HIGLE. Overall, we elucidated the first structure of a plant SLX1-lineage protein, showed its HJ resolving activity independent of any regulatory protein, and identified an in-built novel regulatory mechanism engaging its C-terminal region.

SIRT7-dependent deacetylation of NPM promotes p53 stabilization following UV-induced genotoxic stress.

Adaptation to different forms of environmental stress is crucial for maintaining essential cellular functions and survival. The nucleolus plays a decisive role as a signaling hub for coordinating cellular responses to various extrinsic and intrinsic cues. p53 levels are normally kept low in unstressed cells, mainly due to E3 ubiquitin ligase MDM2-mediated degradation. Under stress, nucleophosmin (NPM) relocates from the nucleolus to the nucleoplasm and binds MDM2, thereby preventing degradation of p53 and allowing cell-cycle arrest and DNA repair. Here, we demonstrate that the mammalian sirtuin SIRT7 is an essential component for the regulation of p53 stability during stress responses induced by ultraviolet (UV) irradiation. The catalytic activity of SIRT7 is substantially increased upon UV irradiation through ataxia telangiectasia mutated and Rad3 related (ATR)-mediated phosphorylation, which promotes efficient deacetylation of the SIRT7 target NPM. Deacetylation is required for stress-dependent relocation of NPM into the nucleoplasm and MDM2 binding, thereby preventing ubiquitination and degradation of p53. In the absence of SIRT7, stress-dependent stabilization of p53 is abrogated, both in vitro and in vivo, impairing cellular stress responses. The study uncovers an essential SIRT7-dependent mechanism for stabilization of the tumor suppressor p53 in response to genotoxic stress.

Factors Associated with Nursing Professionalism: Insights from Tertiary Care Center in India.

BACKGROUND: Professionalism among nurses plays a critical role in ensuring patient safety and quality care and involves delivering competent, safe, and ethical care while also working with clients, families, communities, and healthcare teams. AIMS AND OBJECTIVES: To assess the level of nursing professionalism and the factors affecting professionalism among nurses working at a tertiary care center in India. METHODS: A descriptive cross-sectional study was conducted from October 2022 to March 2023 using a total enumeration sampling technique. Following institutional ethics committee approval, standardized tools were administered consisting of Nursing Professionalism Scale and socio-demographic, personal, and organizational characteristics. RESULTS: A total of 270 nurses participated, with a response rate of 93.7%. The mean age of the participants was 27.33 ± 2.75 years, with the majority being female (82.6%) and belonged to the age group of 23-27 years (59.6%). More than half of the nurses exhibited high professionalism (53%), with the highest and lowest median scores for professional responsibility (29.0) and valuing human beings (13.0) respectively. Multivariate regression analysis demonstrated that, compared with their counterparts, nurses with a graduate nursing qualification (AOR = 4.77, 95% CI = 1.16-19.68), up-to-date training (AOR = 4.13, 95% CI = 1.88-9.06), and adequate career opportunity (AOR = 33.91, 95% CI = 14.48-79.39) had significant associations with high nursing professionalism. CONCLUSION/IMPLICATIONS FOR PRACTICE: The majority of the nurses had high professionalism, particularly in the domains of professional responsibility and management. Hospitals and healthcare institutions can use these findings to develop policies and prioritize opportunities for nurses to attend conferences and workshops to enhance their professional values, ultimately leading to improved patient care outcomes. PATIENT AND PUBLIC CONTRIBUTION: No patient or public contribution.

Effect of different doses of dexmedetomidine as an adjuvant to lignocaine nebulization: A comparative study during awake flexible fiberoptic bronchoscopy.

Background and Aims: Mild to moderate sedation during bronchoscopy is essential for patient safety, comfort during and after the procedure, and to facilitate the performance of the bronchoscopist. Dexmedetomidine is a highly selective, centrally acting α-2 agonist used to provide conscious sedation during various procedures. The aim of this study was to compare the efficacy of three different doses of dexmedetomidine nebulization as an adjuvant to lignocaine during bronchoscopy. Material and Methods: Ninety American Society of Anesthesiologists physical status I/II patients, aged from 18 to 60 years, scheduled for an elective bronchoscopy, were recruited. They were divided into three groups: 30 patients in each group. Group I: The patient was nebulized with a mixture of 4 ml of 4% lignocaine and dexmedetomidine 0.5 µg/kg. Group II: The patient was nebulized with a mixture of 4% lignocaine, 4 ml, and dexmedetomidine, 1 µg/kg. Group III: The patient was nebulized with 4% lignocaine 4 ml and dexmedetomidine 1.5 µg/kg. Results: The mean cough score was (1.17 ± 0.37), (1.40 ± 0.49), and (1.70 ± 0.75) in group III, group II, and group I, respectively. A significant difference was found between the groups. Patients were more comfortable with a statistically significant difference in the comfort score in group III as compared to group II and group I. Conclusion: Dexmedetomidine nebulization in a dose of 1.5 µg/kg (compared to 1 µg/kg or 0.5 µg/kg) as an adjuvant to lignocaine, provides better bronchoscopy conditions and patient satisfaction.

Efficacy and safety of degludec U100 versus glargine U300 for the early postoperative management of patients with type 2 diabetes mellitus undergoing coronary artery bypass graft surgery: A non-inferiority randomized trial.

AIMS: To compare the efficacy and safety of degludec U100 versus glargine U300 for the early postoperative management of patients with type 2 diabetes mellitus (T2D) undergoing coronary artery bypass graft (CABG) surgery. METHODS: A total of 239 patients were randomly assigned (1:1) to receive a basal-bolus regimen in the early postoperative period using degludec U100 (n = 122) or glargine U300 (n = 117) as basal and glulisine before meals. The primary outcome was mean differences between groups in their daily BG concentrations. The major safety outcome was the occurrence of hypoglycemia. RESULTS: There were no differences in mean daily BG concentrations (157 vs. 162 mg/dl), mean percentage of readings within target BG of 70-180 mg/dl (74% vs. 73%), daily basal insulin dose (19 vs. 21 units/day), length of stay (median [IQR]: 9 vs. 9 days), or hospital complications (21.3% vs. 21.4%) between treatment groups. There were no differences in the proportion of patients with BG <70 mg/dl (15.6% vs. 23.1%) or <54 mg/dl (1.6% vs. 4.3%) between degludec-100 and glargine-300 groups. CONCLUSIONS: Treatment with degludec U100 is as effective and safe as glargine U300 for the early postoperative hospital management of patients with T2D undergoing CABG.

Plants and endophytes interaction: a "secret wedlock" for sustainable biosynthesis of pharmaceutically important secondary metabolites.

Many plants possess immense pharmacological properties because of the presence of various therapeutic bioactive secondary metabolites that are of great importance in many pharmaceutical industries. Therefore, to strike a balance between meeting industry demands and conserving natural habitats, medicinal plants are being cultivated on a large scale. However, to enhance the yield and simultaneously manage the various pest infestations, agrochemicals are being routinely used that have a detrimental impact on the whole ecosystem, ranging from biodiversity loss to water pollution, soil degradation, nutrient imbalance and enormous health hazards to both consumers and agricultural workers. To address the challenges, biological eco-friendly alternatives are being looked upon with high hopes where endophytes pitch in as key players due to their tight association with the host plants. The intricate interplay between plants and endophytic microorganisms has emerged as a captivating subject of scientific investigation, with profound implications for the sustainable biosynthesis of pharmaceutically important secondary metabolites. This review delves into the hidden world of the "secret wedlock" between plants and endophytes, elucidating their multifaceted interactions that underpin the synthesis of bioactive compounds with medicinal significance in their plant hosts. Here, we briefly review endophytic diversity association with medicinal plants and highlight the potential role of core endomicrobiome. We also propose that successful implementation of in situ microbiome manipulation through high-end techniques can pave the way towards a more sustainable and pharmaceutically enriched future.

Study of Judd-Ofelt, Urbach energy and photosensitization process in luminescent Sm(III) complexes with heterocyclic ligands.

Six samarium (III) complexes were synthesised by employing the ß-ketocarboxylic acid as main ligand and five N-donor systems as ancillary ligands through the environmentally safe liquid-assisted grinding method. Various characterisation techniques were employed to determine the structure of the complexes i.e. NMR, IR, XRD and SEM. Photoluminescent studies were carried out in solid as well as in solution form. In solid and solution form emission spectra show maximum intensity peak at 604 and 602 nm, respectively, assigned to 4G5/2 → 6H7/2 transition which explains orange emission on UV excitation in complexes. CCT, CP, colorimetric parameters and quantum yield (relative and intrinsic) of the synthesized complexes were calculated. With the help of reflectance spectra, band gap and Urbach energy were determined. Lasing parameters were also calculated by employing FWHM values obtained from Gaussian fitting. Energy transfer study revealed the efficacious energy transfer from ligand to metal's emissive level. Further antimicrobial studies revealed higher activity in case of complexes in comparison to ligand.

Computational and optoelectronic quantification of semi-conducting, warm ruby red color emanating Eu3+ complexes with hetro-cyclic ligands.

Six Eu3+ complexes were synthesised with ß-keto acid as main ligand and secondary ligands through liquid assisted grinding method. These complexes were characterised by various techniques such as spectroscopic technique, XRD, EDAX, SEM analysis, thermal technique, Urbach energy and optical band gap investigation. The luminous photophysical properties were studied by PL spectroscopy in solid as well as solution phase and some theoretical calculation was done to investigate the radiative (Arad) & non-radiative (Anrad) transition rate, quantum efficiency (ɸ), Judd Ofelt parameters for 5D0 → 7F2,4 transitions in both states. Judd Ofelt parameters were also calculated by the JOES software and the outcomes are well harmonised with theoretical values. The complexes have CIE color coordinate value in ruby red region and above 88.65% color purity in both phases, which made them attractive candidates for red light-emitting displays. 5D0 → 7F2 transition was proposed as a laser emission transition owing to their high branching ratio (67.18-74.24%) in solid and (60.09-74.40%) in solution phase. Computational methods were employed to determine the structure and energy of various molecular orbitals. Antimicrobial assay of complexes was also rationalised and found that the complexes are pertinent as good bactericidal and fungicidal agents in pharmaceutical industry.

Exploration of Optical and Radiative Properties of Fluorinated ß-keto Carboxylate Tb3+ Complexes Emanating Cool Green Light.

Tb3+ complexes with ß-ketocarboxylic acid as main ligand and heterocyclic systems as auxiliary ligand were synthesized and analyzed to assess their prospective relevance as green light emitting material. The complexes were characterized via various spectroscopic techniques and were found to be stable up to ≈ 200 ℃. Photoluminescent (PL) investigation was performed to assess the emissive nature of complexes. Longest luminescence time of decay (1.34 ms) and highest intrinsic quantum efficiency (63.05%) were fetched for complex T5. Color purity of complexes was found to be in range 97.1 - 99.8% which demonstrated the aptness of these complexes in green color display devices. NIR Absorption spectra were employed to evaluate Judd-Ofelt parameters to appraise the luminous performance and environment encircling Tb3+ ions. The JO parameters were found to follow the order: Ω2 > Ω4 > Ω6 and suggested the higher covalence character in complexes. Theoretical branching ratio in the range 65.32 - 72.68%, large stimulated emission cross section and narrow FWHM for 5D4 → 7F5 transition unlocked the relevance of these complexes as a green color laser media. Band gap and Urbach analysis were consummated via enforcing nonlinear curve fit function on absorption data. Two band gaps with values in between 2.02 - 2.93 eV established the prospective use of complexes in photovoltaic devices. Energies of HOMO and LUMO were estimated employing geometrically optimized structures of complexes. Investigation of biological properties accomplished via antioxidant and antimicrobial assays which communicated their applicability in biomedical domain.

New Highly Luminescent Red Emitting Complexes: Synthesis, Characterization, Judd-Ofelt Intensity Parameters and Pharmacological Investigations.

A series of new red luminescent Eu(III) complexes were integrated by ß-hydroxyketone ligand 2-(4-chlorophenyl)-1-(2-hydroxy-4,6-dimethoxyphenyl)ethan-1-one (CHDME) as main ligand and 1,10-phenanthroline (phen) or 5,6-dimethyl-1,10-phenanthroline (dmphen) or bathophenanthroline (bathophen) as ancillary ligand. The complexes were synthesised by solution precipitation method. The CHDME is taken as ligand and its analogous Eu(III) complexes were characterized by elemental analysis, FT-IR and 1H-NMR. The photoluminescent properties were also examined in solid state. The Judd-Ofelt intensity parameters (Ω2 and Ω4) and luminescence quantum efficiency (η) of Eu(III) complexes were additionally figured out as per luminescence spectra and decay cure. UV analysis and optical band was also calculated. Computational analysis were carried out and optical band and Judd-Ofelt intensity parameters were determined. Furthermore, the pharmacological activities such as antimicrobial and antioxidant activity of ligand CHDME and its analogous Europium complexes were also examined. The methods used were tube dilution method for calculating antimicrobial activity and DPPH free radical method for antioxidant activity.