Refractive index-assisted UV/Vis spectrophotometry to overcome spectral interference by impurities.

A major challenge hindering the application of techniques like UV/Vis spectrophotometry in determining concentration is spectral interference from contaminants. Since molar absorptivities vary significantly, even minuscule amounts of specific contaminants may cause relatively large errors in UV/Vis spectrophotometry based quantification. Current methods to deal with this are slow, cost-intensive, or ineffective for unknown interferents.

Real-Time Blinking Suppression of Perovskite Quantum Dots by Halide Vacancy Filling.

Despite the excellent optoelectronic properties of halide perovskites, the ionic and electronic defects adversely affect the stability and durability of perovskites and their devices. These defects, intrinsic or produced by environmental factors such as oxygen, moisture, or light, not only cause chemical reactions that disintegrate the structure and properties of perovskites but also induce undesired photoluminescence blinking to perovskite quantum dots and nanocrystals. Blinking is also caused by the nonradiative Auger processes in the photocharged quantum dots or nanocrystals.

Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment.

Virtually all SARS-CoV-2 vaccines currently in clinical testing are stored in a refrigerated or frozen state prior to use. This is a major impediment to deployment in resource-poor settings. Furthermore, several of them use viral vectors or mRNA.

HS Generation from CS Hydrolysis at a Dinuclear Zinc(II) Site.

The controlled generation of hydrogen sulfide (HS) under biologically relevant conditions is of paramount importance due to therapeutic interests. Via exploring the reactivity of a structurally characterized phenolate-bridged dinuclear zinc(II)-aqua complex {Zn(OH)}(ClO) () as a hydrolase model, we illustrate in this report that complex readily hydrolyses CS in the presence of EtN to afford HS. In contrast, penta-coordinated [Zn] sites in dinuclear {(Zn)(μ-X)}(ClO) complexes (, X = OAc; , X = dimethylpyrazolyl) do not mediate CS hydrolysis in the presence of externally added water and EtN presumably due to the unavailability of a coordination site for water at the [Zn] centers.

Deoxygenation of nitrosoarene by N-heterocyclic carbene (NHC): an elusive Breslow-type intermediate bridging carbene and nitrene.

N-Heterocyclic carbene (NHC) activates and deoxygenates nitrosoarene (ArNO) to afford arylnitrene (ArN), thereby portraying a fundamental route connecting two 6e- species. A combination of spectroscopic and computational studies suggests that the interaction of ArNO with NHC affords a transient 2,2'-diamino imine-N-oxide as a key intermediate in ArNO deoxygenation.

A swarm intelligence modeling approach reveals noble gas cluster configurations confined within carbon nanotubes.

Confinement of atoms and molecules brings forth fascinating properties to chemical systems that are otherwise not known in the bulk. Carbon nanotubes (CNTs) and fullerenes are excellent hosts for probing the confinement effects. Herein, we explore the potential energy surfaces of large noble gas clusters, Ngn (Ng = He, Ne and Ar; n = 10, 20, 30, 40, and 50), in the confines of CNTs of various lengths.

Acoustic and ultrasonographic characterization of polychloroprene, beeswax, and carbomer-gel to mimic soft-tissue for diagnostic ultrasound.

Materials with acoustic properties similar to soft-tissue are essential as tissue-mimicking materials (TMMs) for diagnostic ultrasound (US). The velocity (c), acoustic impedance (AI) and attenuation coefficient of US (µ) in a material collectively define its acoustic property. In this work, the acoustic properties of polychloroprene rubber, beeswax, and Carbomer-gel are determined.

Understanding the effects of shape, material and location of incorporation of metal nanoparticles on the performance of plasmonic organic solar cells.

Truncated octahedral gold (Au) nanoparticles (NPs), Au nanocubes (NCs)-, and silver (Ag) NCs are used to study the effect of NPs shape, material and incorporation location on the performance of poly(3-hexylthiophene):[6,6]-phenyl-C-butyric acid methyl ester (P3HT:PCBM) based inverted bulk heterojunction (BHJ) organic solar cells (OSCs). Plasmonic OSCs (POSCs) with NPs incorporated as an interfacial layer between zinc oxide (ZnO) and active layer showed highest power conversion efficiency (PCE) and short circuit current density ( ) values for all kind of shapes and material compared to POSCs with NPs blended into the active layer. Near-field enhancement as well as enhanced forward scattering cross section is attributed for POSC performance improvement.

Air-processed active-layer of organic solar cells investigated by conducting AFM for precise defect detection.

Atmospheric processing of organic solar cells (OSCs) has already emerged and will be a challenge to emulate with the existing market leaders in terms of overall cost reduction and large scale production. However, the presence of defects in the active layer of OSC needs to be identified effectively to minimize the performance degradation involved. In this work, conventional bulk-heterojunction (BHJ) OSCs are fabricated entirely in air having an efficiency () up to 4.

Lithium-Ion-Based Electrochemical Energy Storage in a Layered Vanadium Formate Coordination Polymer.

A vanadium formate (VF) coordination polymer and its composite with partially reduced graphene oxide (prGO), namely VF-prGO, can be applied as anode materials for Li-ion based electrochemical energy storage (EcES) systems in the potential range of 0-3 V (vs Li /Li). This study shows that a reversible capacity of 329 mAh g at a current density of 50 mA g after 50 cycles can be realized for VF along with a high rate capability. The composite exhibits even a higher capacity of 504 mAh g at 50 mA g .

Near-Quantitative Triplet State Population via Ultrafast Intersystem Crossing in Perbromoperylenediimide.

Perylenediimide (PDI) derivatives are essential organic semiconductor materials in a variety of photofunctional devices. By virtue of the large energy gap between the singlet and triplet excited states (Δ = 1.1 eV), augmentation of the triplet state population in monomeric PDI is a challenging task.

Temperature-Dependent Emission and Turn-Off Fluorescence Sensing of Hazardous "Quat" Herbicides in Water by a Zn-MOF Based on a Semi-Rigid Dibenzochrysene Tetraacetic Acid Linker.

A zinc metal-organic framework, i.e., Zn-MOF (Zn-DBC), with ca.

O-H vibrational motions promote sub-50 fs nonadiabatic dynamics in 3-hydroxypyran-4-one: interplay between internal conversion and ESIPT.

A theoretical study is used to explore the involvement of O-H vibrational motions in the S0 → S2 photoinduced dynamics of 3-hydroxypyran-4-one (3-HOX). Two transitions, S0 → S1 and S0 → S2, are attributed to the experimentally observed electronic absorption spectral features in the range of 3.5-5.

Ultra-thin anodized aluminium dielectric films: the effect of citric acid concentration and low-voltage electronic applications.

Anodically oxidized, ultra-thin (d < 10 nm) aluminium films emerge as the dielectric of choice for low-cost thin film capacitors (TFCs), thin film transistors (TFTs), and bio- and chemical sensors. In this work, the dielectric properties of ultra-thin aluminium oxide films grown by anodization in aqueous solutions of citric acid (CA) have been studied. It is observed that the electrolyte strength variation from 0.

Terahertz spectroscopic signature of the charge density wave in the spin-ladder compound, SrCuO.

We provide spectroscopic evidence for the charge density wave (CDW) phason mode at ≈0.93 THz in the two-leg, spin-1/2 ladders of SrCuO using terahertz time-domain spectroscopy. We find that annealing in an oxygen atmosphere or doping with a low concentration of Co (≾1%) does not affect the CDW phason mode.

Identification of a receiver triplet state in the ultrafast intersystem crossing of carbonylpyrenes.

The near-unity triplet quantum yield of photoexcited carbonyl functionalized pyrenes is theoretically investigated. The estimated energetics of singlet-triplet manifolds and relevant spin-orbit coupling parameters strongly suggest triplet state formation via the S→ T/T pathway. Quantum wavepacket dynamics of triplet manifolds within the linear vibronic coupling approach reveal that the receiver triplet state would undergo rapid internal conversion decay to the lower triplet state(s), facilitating efficient triplet generation by minimizing the reverse intersystem crossing possibilities.

Gold nanoparticle on semiconductor quantum dot: Do surface ligands influence Fermi level equilibration.

Semiconductor-metal heterojunction nanostructures possess an ability to store electrons upon photoexcitation through Fermi level equilibration. The unique role of capping ligands in modulating the equilibration of Fermi level in CdSe-Au heteronanostructures is explored by taking alkyl thiols and alkyl amines as examples. Alkyl thiol having its highest occupied molecular orbital (HOMO) above the valence band of the heterojunction nanostructure inhibits the exciton recombination by scavenging the photogenerated hole.

Phenol Reduces Nitrite to NO at Copper(II): Role of a Proton-Responsive Outer Coordination Sphere in Phenol Oxidation.

In the view of physiological significance, the transition-metal-mediated routes for nitrite (NO) to nitric oxide (NO) conversion and phenol oxidation are of prime importance. Probing the reactivity of substituted phenols toward the nitritocopper(II) cryptate complex []Cu(κON)(ClO) (), this report illustrates NO release from nitrite at copper(II) following a proton-coupled electron transfer (PCET) pathway. Moreover, a different protonated state of with a proton hosted in the outer coordination sphere, [H]Cu(κON)(ClO) (), also reacts with substituted phenols via primary electron transfer from the phenol.

Metastable Chiral Azobenzenes Stabilized in a Double Racemate.

The self-assembly of chiral organic chromophores is gaining huge significance due to the abundance of supramolecular chirality found in natural systems. We report an interdigitated molecular assembly involving axially chiral octabrominated perylenediimide (OBPDI) which transfers chiral information to achiral aromatic moieties. The crystalline two-component assemblies of OBPDI and electron-rich aromatic units were facilitated through π-hole⋅⋅⋅π donor-acceptor interactions, and the charge-transfer characteristics in the ground and excited states of the OBPDI cocrystals were established through spectroscopic and theoretical techniques.

Insulin signalling elicits hunger-induced feeding in Drosophila.

Insulin, a highly conserved peptide hormone, links nutrient availability to metabolism and growth in animals. In fed states insulin levels remain high and in animals that are food deprived insulin signalling drops. Here, we report that in Drosophila, feeding elicited by short periods of starvation is dependent on insulin signalling.

Adsorption of Monocyclic Carbon Rings on Graphene: Energetics Revealed via Continuum Modeling.

Gas-phase spectroscopic detection of tiny carbon clusters is a recent success story in the area of carbon cluster research. However, experimental production and isolation of these clusters are extremely difficult because of their high reactivity. One possibility to isolate the generated clusters would be to deposit them on graphene and to desorb them for subsequent use.

Quantum Transmission of He Isotopes through Crown Ether-Embedded Graphene Nanomeshes: An Eckart Potential Approach.

The remarkable performance of carbon membranes for the selective passage of various species has led to extensive research in designing smart membranes. The mechanical stability of graphene in conjunction with the excellent host-guest chemistry of crown ethers makes the recently synthesized family of crown ether-embedded graphene nanomeshes promising candidates for sieving applications. Inspired by the excellent control over pore architectures offered by such nanomeshes, we investigate the abilities of crown ether-embedded graphene nanomeshes for noble gas separation by the size-sieving mechanism and for He isotope separation by the quantum sieving mechanism.

A matter of taste: the adverse effect of pollen compounds on the pre-ingestive gustatory experience of sugar solutions for honeybees.

In addition to sugars, nectar contains multiple nutrient compounds in varying concentrations, yet little is known of their effect on the reward properties of nectar and the resulting implications for insect behaviour. We examined the pre-ingestive responses of honeybees to sucrose solutions containing a mix of pollen compounds, the amino acids proline or phenylalanine, or known distasteful substances, quinine and salt. We predicted that in taste and learning assays, bees would respond positively to the presence of nutrient compounds in a sucrose solution.

Photoacoustic elastography imaging: a review.

Elastography imaging is a promising tool-in both research and clinical settings-for diagnosis, staging, and therapeutic treatments of various life-threatening diseases (including brain tumors, breast cancers, prostate cancers, and Alzheimer's disease). Large variation in the physical (elastic) properties of tissue, from normal to diseased stages, enables highly sensitive characterization of pathophysiological states of the diseases. On the other hand, over the last decade or so, photoacoustic (PA) imaging-an imaging modality that combines the advantageous features of two separate imaging modalities, i.

Periostin and Integrin Signaling in Stem Cell Regulation.

Stem cell function is regulated by a huge repertoire of external cues along with stem cell intrinsic genetic and epigenetic factors. These interactions come through a variety of cell adhesion receptors, of which integrins are one of the most important classes. They interact with extracellular matrix (ECM) components and various bound proteins.