Modulating the Optical Properties of Cationic Surfactant Cetylpyridinium Chloride and Hydrazine Mediated Copper Nanoclusters.

This study investigates the modulations in the optical properties of cationic surfactant cetylpyridinium chloride (CPC) and hydrazine-mediated copper nanoclusters (CuNCs). By employing a bottom-up approach, we demonstrate the formation of blue-emitting CuNCs facilitated by CPC and hydrazine, where hydrazine acts both as a reducing and stabilizing agent. The optical properties of the CuNCs were systematically tuned by varying the chain length of the diamine, resulting in emissions ranging from blue to yellow.

Superstructures of copper nanoclusters as NIR TADF emitters: solvent-dependent optical and morphological modulation.

Herein, we report 2-mercaptopyridine-templated copper nanoclusters (CuNCs) which display near infra-red (NIR) emission, both in the solid and colloidal states. Interestingly, the NIR emission can be modulated to orange emission by preparing the CuNCs in a mixed solvent system of chloroform and methanol instead of water. The drastic change in the photo-physical properties of the CuNCs when prepared in two different solvent systems is accompanied by a unique morphological tuning.

Fabrication and optimization of extended-release beads of diclofenac sodium based on Ca cross-linked Taro (Colocasia esculenta) stolon polysaccharide and pectin by quality-by-design approach.

The present investigation was aimed to fabricate and optimize extended-release beads of diclofenac sodium based on an ion-cross-linked matrix of pectin (PTN) and taro (Colocasia esculenta) stolon polysaccharide (TSP) with 2 full factorial design. Total polysaccharide concentration (TPC), polysaccharide ratio (PR), and cross-linker concentration ([CaCl]) were taken as independent factors with two levels of each. Initially, TSP was extracted, purified, and characterized.

Assemble-Disassemble-Reassemble Dynamics in Copper Nanocluster-Based Superstructures.

Assembling metal nanoclusters (MNCs) to form superstructures generates exciting photophysical properties distinct from those of their discrete precursors. Controlling the assembly process of MNCs and understanding the assembly-disassembly dynamics can have implications in achieving the reversible self-assembly of MNCs. The formation of self-assembled copper nanoclusters (CuNCs) as homogeneous superstructures and the underlying mechanisms governing such a process remain unexplored.

Plasmon-emitter coupling in cytosine-rich hairpin DNA-templated silver nanoclusters: Thermal reversibility, white light emission, and dynamics inside live cells.

Bio-templated luminescent noble metal nanoclusters (NCs) have attracted great attention for their intriguing physicochemical properties. Continuous efforts are being made to prepare NCs with high fluorescence quantum yield (QY), good biocompatibility, and tunable emission properties for their widespread practical applications as new-generation environment-friendly photoluminescent materials in materials chemistry and biological systems. Herein, we explored the unique photophysical properties of silver nanoclusters (AgNCs) templated by cytosine-rich customized hairpin DNA.

Deciphering the liquid-liquid phase separation induced modulation in the structure, dynamics, and enzymatic activity of an ordered protein β-lactoglobulin.

Owing to the significant role in the subcellular organization of biomolecules, physiology, and the realm of biomimetic materials, studies related to biomolecular condensates formed through liquid-liquid phase separation (LLPS) have emerged as a growing area of research. Despite valuable contributions of prior research, there is untapped potential in exploring the influence of phase separation on the conformational dynamics and enzymatic activities of native proteins. Herein, we investigate the LLPS of β-lactoglobulin (β-LG), a non-intrinsically disordered protein, under crowded conditions.

Exploring the Specific Role of Iron Center in the Catalytic Activity of Human Serum Transferrin: CTAB-Induced Conformational Changes and Sequestration by Mixed Micelles.

Conformational changes play a seminal role in modulating the activity of proteins. This concept becomes all the more relevant in the context of metalloproteins, owing to the formation of specific conformation(s) induced by internal perturbations (like a change in pH, ligand binding, or receptor binding), which may carry out the binding and release of the metal ion/ions from the metal binding center of the protein. Herein, we investigated the conformational changes of an iron-binding protein, monoferric human serum transferrin (Fe-hTF), using several spectroscopic approaches.

An Electrical Resistance Diagnostic for Conductivity Monitoring in Laser Powder Bed Fusion.

With the growing interest in metal additive manufacturing using laser powder bed fusion (LPBF), there is a need for advanced in-situ nondestructive evaluation (NDE) methods that can dynamically monitor manufacturing process-related variations, that can be used as a feedback mechanism to further improve the manufacturing process, leading to parts with improved microstructural properties and mechanical properties. Current NDE techniques either lack sensitivity beyond build layer, are costly or time-consuming, or are not compatible for in-situ integration. In this research, we develop an electrical resistance diagnostic for in-situ monitoring of powder fused regions during laser powder bed fusion printing.

Crystallization, Differential Growth, and Multicolor Emission of Silver Nanoclusters.

The real-time monitoring of the stepwise growth process of the molecular crystal reveals a conclusive understanding of the morphological evolution, which otherwise remains elusive during the conventional crystallization processes. Herein, we report the crystallization of silver nanoclusters (AgNCs) with special emphasis on their differential growth and multicolor emissive properties. A subtle variation of the methanol (MeOH) proportion in the reaction mixture induces the differential growth of these AgNCs, and thereby, a dramatic modulation in their optical properties was observed.

Mechanistic elucidation of the catalytic activity of silver nanoclusters: exploring the predominant role of electrostatic surface.

The core and the ligand shell of metal nanoclusters (MNCs) have an influential role in modulating their spectroscopic signatures and catalytic properties. The aspect of electrostatic interactions to regulate the catalytic properties of MNCs has not been comprehensively addressed to date. Our present work conclusively delineates the role of the metal core and the electrostatic surface of MNCs involved in the reduction of nitroarenes.

pH-Switchable phenylalanine-templated copper nanoclusters: CO probing and efficient peroxidase mimicking activity.

Inter-cluster conversion through the strategic tuning of external stimuli and thereby modulation of the optical properties of metal nanoclusters (MNCs) is an emerging domain for exploration. Herein, we report the preparation of blue-emitting CuNCs using phenylalanine (Phe) as a template under acidic conditions (pH ∼ 4). The as-prepared CuNCs exhibit a sequential tuning of the photophysical properties upon varying the pH of the solution from pH ∼4 to pH ∼12.

Profile of Childhood Glaucoma Attending a Tertiary Eye Care Center in Northern India.

Purpose: To ascertain the prevalence and clinical features of the various types of childhood glaucoma at a tertiary eye care hospital in Northern India.

Materials And Methods: Retrospective chart review of all children less than 16 years of age with childhood glaucoma who presented from 1 April 2014 to 31 March 2019, who was diagnosed to have any subtype of childhood glaucoma as per Childhood Glaucoma Research Network (CGRN) classification and advised appropriate management.

Results: Out of 405 children with childhood glaucoma, 36% had primary glaucoma, whereas the rest had secondary glaucoma.

Fluorescence Resonance Energy Transfer in a Supramolecular Assembly of Luminescent Silver Nanoclusters and a Cucurbit[8]uril-Based Host-Guest System.

The understanding of interactions between organic chromophores and biocompatible luminescent noble metal nanoclusters (NCs) leading to an energy transfer process that has applications in light-harvesting materials is still in its nascent stage. This work describes a photoluminescent supramolecular assembly, made in two stages, employing an energy transfer process between silver (Ag) NCs as the donor and a host-guest system as the acceptor that can find potential applications in diverse fields. Initially, we explored the host-guest chemistry between a cationic guest ethidium bromide and cucurbit[8]uril host to modulate the fluorescence property of the acceptor.

Solvent-Induced Modulation in the Optical Properties of Copper Nanoclusters and Revealing the Isomeric Effect of Templates.

The solvent plays an influential role in controlling the nucleation process of metal nanoclusters (MNCs) and thereby significantly modulates their optical signatures. Herein, we have demonstrated the solvent-induced modulation in the optical properties of copper nanoclusters (CuNCs), primarily governed by the solvent polarity. During the preparation of para-mercaptobenzoic acid (p-MBA)-templated CuNCs, the simultaneous formation of blue-emitting CuNCs (B-CuNCs) and red-emitting CuNCs (R-CuNCs) were observed up to 7 h of reaction time, reflected from the systematic increment in the photoluminescence (PL) intensity at 420 nm and 615 nm, respectively.

Rh(III)-Catalyzed -C-H Amidation of Naphthalene and Perylene Monoimides.

The direct formation of a C-N bond at the -position of naphthalene monoimides (NMI) and perylene monoimides (PMI) is reported herein using dioxazolones as the amide source. This method affords direct access to -amino NMI and PMI through an amidation and deprotection sequence. One-pot telescopic -bromination of amino PMIs was also achieved.

Combined theoretical and experimental insights on DNA and BSA binding interactions of Cu(ii) and Ni(ii) complexes along with the DPPH method of antioxidant assay and cytotoxicity studies.

This present study delineates the syntheses, detailed characterization and anti-proliferative potential against SiHa (cervical cancer cell) of two mononuclear complexes of Cu(ii) and Ni(ii) using a Schiff base ligand (L) derived from 2-hydroxybenzaldehyde and -methyl-propane 1,3-diamine. The crystallographic results show the centro-symmetric space group of orthorhombic nature () for Cu(ii) complex (1) where the central Cu(ii) has an inversion center symmetry with six co-ordinations resulting in a distorted octahedral geometry. Whereas, in complex (2), the two independent Ni(ii) atoms present in the special position within version symmetry and form a distorted geometry of octahedral nature with six coordinations.

Multi-Defect Detection in Additively Manufactured Lattice Structures Using 3D Electrical Resistance Tomography.

Cellular lattice structures possess high strength-to-weight ratios suitable for advanced lightweight engineering applications. However, their quality and mechanical performance can degrade because of defects introduced during manufacturing or in-service. Their complexity and small length scale features make defects difficult to detect using conventional nondestructive evaluation methods.

Biophysical insights into the binding capability of Cu(II) schiff base complex with BSA protein and cytotoxicity studies against SiHa.

Herein, we have explored the effects of chlorinated mononuclear Cu(II) complex upon binding with BSA protein (bovine serum albumin) and its anti-proliferative potentiality against SiHa cell. The complex was synthesized involving a Schiff base ligand having N,N,O donor centers and characterized by several spectroscopic studies. Structure, DFT studies and Hirshfeld surface (HS) analyses were identified using crystallographic computational studies.

Structure and Transition Dynamics of Intrinsically Disordered Proteins Probed by Single-Molecule Spectroscopy.

Intrinsically disordered proteins (IDPs) are a class of proteins that do not follow the unanimated perspective of the structure-function paradigm. IDPs enunciate the dynamics of motions which are often difficult to characterize by a particular experimental or theoretical approach. The chameleon nature of the IDPs is a result of an alteration or transition in their conformation upon binding with ligands.

Deciphering the Nanoconfinement Effect on the Folding Pathway of Promoter-Based Intercalated-Motif DNA by Single-Molecule Förster Resonance Energy Transfer.

Intercalated-motif (i-motif) DNA formed by cytosine (C)-rich sequences has been considered a novel target in anticancer research. Interestingly, this type of noncanonical DNA structure is highly dynamic and can display several conformational polymorphisms based on the immediate surrounding environment. However, studies regarding the folding pathway of i-motifs having disease-specific sequences under a confined environment at physiological pH are relatively scarce.

Association of primary angle-closure disease in patients with retinal vein occlusion in North Indian population.

Purpose: To determine the association of primary angle-closure disease (PACD) in patients with retinal vein occlusion (RVO) at a tertiary eye care center in North India.

Methods: It is a cross-sectional, observational study. Sixty consecutive patients with retinal vein occlusion within a period of one year from a single tertiary eye care center were enrolled.

A Bioinspired Light Harvesting System in Aqueous Medium: Highly Efficient Energy Transfer through the Self Assembly of β-Sheet Nanostructures of Poly-d-Lysine.

Nature has beautifully assembled its light harvesting pigments within protein scaffolds, which ensures a very high energy transfer. Designing a highly efficient artificial bioinspired light harvesting system (LHS) thus requires the nanoscale spatial orientation and electronic control of the associated chromophores. Although DNA has been used as a scaffold to organize chromophores, proteins or polypeptides, however, are very rarely explored.

Macrocyclic Cavitand β-Cyclodextrin Inhibits the Alcohol-Induced Trypsin Aggregation.

Trypsin, the most abundant pancreatic protein, aids in protein digestion by hydrolysis and exhibits aggregation propensity in presence of alcohol, which can further lead to pancreatitis and eventually pancreatic cancer. Herein, by several experimental and theoretical approaches, we unearth the inhibition of alcohol-induced aggregation of Trypsin by macrocyclic cavitand, β-cyclodextrin (β-CD). β-CD interacts with the native protein and shows inhibitory effect in a dose dependent manner.

Rh(III)-Catalyzed One-Step Synthesis of ortho-Alkynylated Perylene Imide Dyes: Optical and Electrochemical Properties of New Derivatives.

A one-step Rh-catalyzed site-selective ortho-C-H alkynylation of perylene as well as naphthalene mono- and diimides is reported. A single step regioselective access to ortho-C-H alkynylated derivatives of these ryleneimides not only increases the step economy of the ortho-functionalization on these dyes but also provides a quick access route towards highly functionalized dyes that have potential optoelectronic applications. Increased solubility of tetra(triisopropylsilyl)acetylenyl PDIs in organic solvents greatly enhances their utility for further derivatization.