DDQ as a Mild and Efficient Catalyst for Deprotection of Tetrahydropyranyl Ethers

In the presence of a catalytic amount of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), tetrahydropyranyl ethers are readily hydrolysed to their corresponding alcohols in wet acetonitrile under mild conditions.     

Electrochemical impedance spectroscopic studies of copper dissolution in arginine–hydrogen peroxide solutions

Anodic dissolution of copper in arginine and hydrogen peroxide-based medium suitable for chemical mechanical planarization slurry formulation was investigated using electrochemical impedance spectroscopy. Potentiodynamic polarization and impedance data were acquired for copper dissolving in hydrogen peroxide and arginine solution. Reaction mechanism analysis (RMA) was employed to determine the mechanistic pathway of copper dissolution. RMA analysis indicates that a stable passivating film does not form on the copper surface, and the direct dissolution of copper was also ruled out. A two-step mechanism involving cupric oxide as an intermediate species is proposed. The data were also fit to an electrical equivalent circuit to obtain insight into the variation of the parameters with the overpotential. The modeled data for the two-step mechanism captures the essential features of the impedance spectra at various overpotentials.     

Different approaches in thin-layer chromatography for enantioresolution of acebutolol using colistin sulfate as chiral selector

JPC – Journal of Planar Chromatography – Modern TLC - This work reports the enantioresolution of (RS)-acebutolol (ACB) by a thin-layer chromatographic method involving colistin sulfate...     

Evaluation of transfer factor and ecological half life of 137Cs in terrestrial matrices around Kakrapar Gujarat Site,India during 1993–2019

Journal of Radioanalytical and Nuclear Chemistry - The activity of 137Cs was measured in different terrestrial samples around Kakrapar Gujarat site. Transfer Factor and Ecological half-life of...     

Synthesis and biological activities of 2-methyl-4-N-2′-cyanoethyl-N-substituted benzaldehydes and their derivatives

Synthesis and antiAIDS, anticancer, antitubercular, fungicidal and antibacterial activities of 2-methyl-4-N-2′-cyanoethyl-N-methane/benzenesulphonylaminobenzaldehyde and their hydrazones are reported.     

Spatially resolved wall temperature measurements during flow boiling in microchannels

Spatial and temporal variations of channel wall temperature during flow boiling microchannel flows using infrared thermography are presented and analyzed. In particular, the top channel wall temperature in a branching microchannel silicon heat sink is measured non-intrusively. Using this technique, time-averaged temperature measurements, with a spatial resolution of 10 μm, are presented over an 18 mm × 18 mm area of the heat sink. Also presented, within a specific sub-region of the heat sink, are intensity maps that are recorded at a rate of 120 frames per second. Time series data at selected point locations in this sub-region are analyzed for their frequency content, and dominant temperature fluctuations are extracted using proper orthogonal decomposition.Results at low-vapor-quality boiling condition indicate that temperatures can be determined from recorded radiation intensities with a temperature uncertainty varying from 0.9 °C at 25 °C to 1.0 °C at 125 °C. The time series data indicate periodic wall temperature fluctuations of approximately 2 °C that are attributed to the passage of vapor slugs. A dominant band of frequencies around 2–4 Hz is suggested by the frequency analysis. Proper orthogonal decomposition results indicate that first six orthogonal modes account for approximately 90% of the variance in temperature. The first mode reconstruction accounts for temporal variations in the dataset in the sub-region analyzed; however the magnitude of fluctuations and spatial variations in temperature are not accurately captured. A reconstruction using the first 25 modes is considered sufficient to capture both the temporal and spatial variations in the data.     

Control of Correlation Using Confinement in Case of Quantum System

This article investigates the behavior of a Moshinsky atom in a 1D harmonic trap. Focus is given on the theoretical foundations of confinement and its impact on the correlation between particles in the Moshinsky atom. The investigation begins by illustrating the (de)localization of the probability density function using Shannon entropy. The basics of correlation and interpretation of correlation using tools such as mutual information and statistical correlation coefficients and how these can be quantified are discussed. Then the concept of confinement is explored. The impact of interaction strength and confinement on Shannon entropy, statistical correlation coefficients, and mutual information is investigated. How interaction strength and confinement can be used to induce correlations between previously uncorrelated particles, as well as how they can be used to suppress correlations between previously correlated particles is discussed. Their implications for quantum information processing and quantum simulation are discussed. In conclusion, confinement is a powerful tool for controlling correlations in quantum systems, and its impact on correlation can be understood through theoretical models. The importance of experimental studies in this field, which provide insights into the behavior of quantum systems under confinement and pave the way for future applications in quantum technology is also emphasized.     

Inhibition of Beta-Lactamase by 1,4-Naphthalenedione from the Plant <Emphasis Type="Italic">Holoptelea integrifolia</Emphasis>

The most important mechanism of the beta-lactam antibiotic resistance is the destruction of the antibiotics by the enzyme beta-lactamase. Use of beta-lactamase inhibitors in combination with antibiotics is one of the successful antibacterial strategies. The inhibitory effect of a phytochemical, 1,4-naphthalenedione, isolated from the plant Holoptelea integrifolia on beta-lactamase is reported here. This compound was found to have a synergistic effect with the antibiotic amoxicillin against a resistant strain of Staphylococcus aureus. The enzyme was purified from the organism and incubated with the compound. An assay showed that the compound can inhibit the enzymatic activity of beta-lactamase. Modeling and molecular docking studies indicated that the compound can fit into the active site of beta-lactamase. Hence, the compound can serve as a potential lead compound for the development of effective beta-lactamase inhibitor that can be used against beta-lactam-resistant microbial strains.     

Phenyl-ring-bearing cationic surfactants: effect of ring location on the micellar structure

A series of isomeric cationic surfactants (S1-S5) bearing a long alkyl chain that carries a 1,4-phenylene unit and a trimethyl ammonium headgroup was synthesized; the location of the phenyl ring within the alkyl tail was varied in an effort to understand its influence on the amphiphilic properties of the surfactants. The cmc's of the surfactants were estimated using ionic conductivity measurements and isothermal calorimetric titrations (ITC); the values obtained by the two methods were found to be in excellent agreement. The ITC measurements provided additional insight into the various thermodynamic parameters associated with the micellization process. Although all five surfactants have exactly the same molecular formula, their micellar properties were seen to vary dramatically depending on the location of the phenyl ring; the cmc was seen to decrease by almost an order of magnitude when the phenyl ring was moved from the tail end (cmc of S1 is 23 mM) to the headgroup region (cmc of S5 is 3 mM). In all cases, the enthalpy of micellization was negative but the entropy of micellization was positive, suggesting that in all of these systems the formation of micelles is both enthalpically and entropically favored. As expected, the decrease in cmc values upon moving the phenyl ring from the tail end to the headgroup region is accompanied by an increase in the thermodynamic driving force (ΔG) for micellization. To understand further the differences in the micellar structure of these surfactants, small-angle neutron scattering (SANS) measurements were carried out; these measurements reveal that the aggregation number of the micelles increases as the cmc decreases. This increase in the aggregation number is also accompanied by an increase in the asphericity of the micellar aggregate and a decrease in the fractional charge. Geometric packing arguments are presented to account for these changes in aggregation behavior as a function of phenyl ring location.