Robust Cd(4,5-Imdb)-MOF for Lewis-Acid Assisted Catalysis and Selective Sensing of 2,4,6-Trinitrophenol.

Developing multifunctional metal-organic frameworks (MOFs) for effective catalysis and sensing remain a significant challenge. This study presents the synthesis of an imidazole-based angular linker, 4,4'-(1-methyl-1H-imidazole-4,5-diyl)dibenzoic acid (4,5-HImdb), which is used in the synthesis of the Cd(4,5-Imdb)-MOF. This MOF demonstrates robust and recyclable properties, making it suitable for solvent-free Strecker synthesis and in the detection of the secondary explosive 2,4,6-trinitrophenol (TNP) molecule, with a limit of detection (LOD) of 7.

Not so inert -tris-chelate cobalt(III) complex of a hydroxy-pyridine functionalized NHC ligand for cyclic carbonate synthesis.

The homoleptic hydroxy-pyridine functionalized Co(III)-NHC complex (2) demonstrates extraordinary catalytic activity towards the CO cycloaddition under mild conditions. Using this catalyst and TBAB, the highest TON (666 667) and TOF (52 713 h) were achieved compared to previously reported cobalt catalysts.

Synthesis of N-heterocycles through alcohol dehydrogenative coupling.

Nitrogen heterocycles are found in the structures of many biologically important compounds, as well as materials used in the synthesis of fine chemicals. Notably, ~59% of US Food and Drug Administration-approved small-molecule drugs contain nitrogen heterocycles. It is therefore meaningful to explore greener or more sustainable methods for their synthesis.

Detection of oral mucosal lesions by the fluorescence spectroscopy and classification of cancerous stages by support vector machine.

Detection of oral mucosal lesions has been performed by an in-house developed fluorescence-based portable device in the present study. A laser diode of 405 nm wavelength and a UV-visible spectrometer are utilized in the portable device as excitation and detection sources. At the 405 nm excitation wavelength, the flavin adenine dinucleotide (FAD) band at 500 nm and three porphyrin bands at 634, 676, and 703 nm are observed in the fluorescence spectrum of the oral cavity tissue.

Speeding-up Hybrid Functional-Based Molecular Dynamics Using Multiple Time-stepping and Resonance-Free Thermostat.

molecular dynamics (AIMD) based on density functional theory (DFT) has become a workhorse for studying the structure, dynamics, and reactions in condensed matter systems. Currently, AIMD simulations are primarily carried out at the level of generalized gradient approximation (GGA), which is at the second rung of DFT functionals in terms of accuracy. Hybrid DFT functionals, which form the fourth rung in the accuracy ladder, are not commonly used in AIMD simulations as the computational cost involved is 100 times or higher.

An interoperable implementation of collective-variable based enhanced sampling methods in extended phase space within the OpenMM package.

Collective variable (CV)-based enhanced sampling techniques are widely used today for accelerating barrier-crossing events in molecular simulations. A class of these methods, which includes temperature accelerated molecular dynamics (TAMD)/driven-adiabatic free energy dynamics (d-AFED), unified free energy dynamics (UFED), and temperature accelerated sliced sampling (TASS), uses an extended variable formalism to achieve quick exploration of conformational space. These techniques are powerful, as they enhance the sampling of a large number of CVs simultaneously compared to other techniques.

In-vivo Testing of Oral Mucosal Lesions with an In-house Developed Portable Imaging Device and Comparison with Spectroscopy Results.

Progression of oral mucosal lesions is generally marked by changes in the concentration of the intrinsic fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD) and porphyrin present in the human oral tissue. In this study, we have probed the changes in FAD and porphyrin by exciting with 405 nm laser light on different sites (tongue, buccal mucosa, lip etc.) of the oral cavity.

Mixed-Valent Stellated Cuboctahedral Cu(2,4-Imdb)-MOF for Trace Water Detection.

Developing an economical and robust sensor using an earth-abundant metal-based metal-organic framework (MOF) to detect trace water content rapidly is crucial for laboratories and chemical industries. Herein, a mixed-valent chiral [{CuCu(2,4-Imdb)(HO)}·Cl] MOF manifests atypical quantitative detection of a trace amount of water [0.016% (v/v)] in organic solvents.

Hybrid Functional and Plane Waves based Ab Initio Molecular Dynamics Study of the Aqueous Fe /Fe Redox Reaction.

Kohn-Sham density functional theory and plane wave basis set based ab initio molecular dynamics (AIMD) simulation is a powerful tool for studying complex reactions in solutions, such as electron transfer (ET) reactions involving Fe /Fe ions in water. In most cases, such simulations are performed using density functionals at the level of Generalized Gradient Approximation (GGA). The challenge in modelling ET reactions is the poor quality of GGA functionals in predicting properties of such open-shell systems due to the inevitable self-interaction error (SIE).

Cyclic Palladium Formamidinate: Synthesis, Structure, Reactivity, and Application to Suzuki-Miyaura Cross-Coupling.

The deprotonation of acyclic palladium amidine chloride () with potassium -butoxide in tetrahydrofuran results in palladium bis(formamidinate) (). undergoes a nucleophilic addition reaction with acetonitrile in the presence of PdCl or Pd(OAc) (OAc = acetate) to give dinuclear cyclic six-membered (triazapentadiene)palladium complexes ( and ). These compounds are also prepared from cyclic six-membered (tap)PdCl (; tap = triazapentadiene) or formamidinium salts (-) with Pd(OAc)/NaOAc in acetonitrile, whereas the direct reaction of with acetonitrile or acrylonitrile resulted in palladium black or an acyclic C-N-coupled product ().

Improving the scaling and performance of multiple time stepping-based molecular dynamics with hybrid density functionals.

Density functionals at the level of the generalized gradient approximation (GGA) and a plane-wave basis set are widely used today to perform ab initio molecular dynamics (AIMD) simulations. Going up in the ladder of accuracy of density functionals from GGA (second rung) to hybrid density functionals (fourth rung) is much desired pertaining to the accuracy of the latter in describing structure, dynamics, and energetics of molecular and condensed matter systems. On the other hand, hybrid density functional based AIMD simulations are about two orders of magnitude slower than GGA based AIMD for systems containing ~100 atoms using ~100 compute cores.

Modified hydrologic regime of upper Ganga basin induced by natural and anthropogenic stressors.

Climate change and anthropogenic activities pose serious threats to river basin hydrology worldwide. The Ganga basin is home to around half a billion people and has been significantly impacted by hydrological alterations in the last few decades. The increasing high-intensity rainfall events often create flash flooding events.

Achieving an Order of Magnitude Speedup in Hybrid-Functional- and Plane-Wave-Based Molecular Dynamics: Applications to Proton-Transfer Reactions in Enzymes and in Solution.

molecular dynamics (MD) with hybrid density functionals and a plane wave basis is computationally expensive due to the high computational cost of exact exchange energy evaluation. Recently, we proposed a strategy to combine adaptively compressed exchange (ACE) operator formulation and a multiple time step integration scheme to reduce the computational cost significantly [ 151102 ]. However, it was found that the construction of the ACE operator, which has to be done at least once in every MD time step, is computationally expensive.

Volume and position change of the stomach during gastric accommodation and emptying: A detailed three-dimensional morphological analysis based on MRI.

Background: The proximal and distal regions of the stomach are thought to have different roles during gastric accommodation and emptying; however, regional changes in gastric structure and function during and after a meal have not been described in detail. This study applied non-invasive imaging to study changes in regional gastric volume and morphology during accommodation and emptying of a liquid nutrient meal.

Method: MRI studies were performed on 16 healthy volunteers.

In vivo detection of oral precancer using a fluorescence-based, in-house-fabricated device: a Mahalanobis distance-based classification.

In vivo detection of oral precancer has been carried out by a fluorescence-based, in-house-developed handheld probe on three groups: oral squamous cell carcinoma (OSCC), dysplastic (precancer), and control (normal). Measurements have been performed on a total of 141 patients and volunteers of different age groups. Excitation wavelength of 405 nm was used and fluorescence emission spectra were recorded in the scan range of 450.

Human Saliva for Oral Precancer Detection: a Comparison of Fluorescence & Stokes Shift Spectroscopy.

We report here a study on human saliva tested as a diagnostic medium for oral cancer detection on three groups: oral squamous cell carcinoma (OSCC), oral sub mucous fibrosis (OSMF; precancer), and healthy controls (normal). Measurements have been conducted using fluorescence spectroscopy with 350 nm excitation and Stokes shift (SS) spectroscopy (SSS) with 120 nm shift from a total of 99 saliva samples. For classification, principal component analysis (PCA) and linear discriminant analysis (LDA) have been applied on the data sets.