Synthesis and Antiviral Evaluation of (1,4-Disubstituted-1,2,3-Triazol)-(E)-2-Methyl-but-2-Enyl Nucleoside Phosphonate Prodrugs

A series of hitherto unknown (1,4-disubstituted-1,2,3-triazol)-(E)-2-methyl-but-2-enyl nucleosides phosphonate prodrugs bearing 4-substituted-1,2,3-triazoles were prepared in a straight approach through an olefin acyclic cross metathesis as the key synthetic step. All novel compounds were evaluated for their antiviral activities against HBV, HIV and SARS-CoV-2. Among these molecules, only compound 15j, a hexadecyloxypropyl (HDP)/(isopropyloxycarbonyl-oxymethyl)-ester (POC) prodrug, showed activity against HBV in Huh7 cell cultures with 62% inhibition at 10 μM, without significant cytotoxicity (IC₅₀ = 66.4 μM in HepG2 cells, IC₅₀ = 43.1 μM in HepG2 cells) at 10 μM.     

Synthesis of linseed oil based biodegradable homo and copolymers: role as multifunctional greener additives in lube oil

Abstract

Homopolymer of linseed oil and its four copolymers with styrene, 1-decene, isodecyl acrylate and octyl acrylate, respectively, have been synthesized in this present context. The prepared polymers are characterized by NMR and FTIR spectroscopy. The molecular weights have been measured by gel permeation chromatography. Their effectiveness as pour point depressant (PPD), viscosity index improver (VII) and their shear stability in terms of permanent shear stability index have been evaluated in lube oil. The copolymers acted as better PPDs than the homopolymer whereas the homopolymer of linseed oil excelled as VII. Further it was observed that all the prepared polymers were stable enough under severe mechanical shear.     

Q-switched Yb-doped nonlinear microstructured fiber laser for the emission of broadband spectrum

We report on an innovative configuration of a supercontinuum laser based on an Yb-doped nonlinear microstructured fiber. Due to this particular fiber design combining amplification and nonlinear properties, a wideband output spectrum is generated in the fiber under the Q-switched regime. By exploiting stimulated Brillouin scattering, high peak power pulses are achieved and contribute to a spectral broadening due to a nonlinear wavelength conversion process. Both infrared (1000-1200 nm) and visible (650-750 nm) spectra are generated with an average power of 200 mW.     

Behavioral Characteristics of Children With Vocal Fold Nodules

Vocal fold nodules (VNs) in children are benign, bilateral lesions occurring on the mid-membranous vocal folds. Repetitive phonotraumatic behavior leading to chronic vocal fold injury and repair is frequently cited as the primary etiology; however, specific behavioral characteristics may predispose some children toward intense and potentially phonotraumatic voice use, thereby contributing secondarily to VN formation. The purpose of this case-control study was to determine whether children with VNs possess unique behavioral characteristics that may predispose them to VN development. Parents of 26 children with VNs (20 boys, 6 girls, mean age=7.2 years, SD=2.5 years), and 29 vocally normal, medical controls (22 boys, 7 girls, mean age=6.7 years, SD=2.4), completed the Childhood Behavior Checklist (CBCL/4-18, Achenbach, 1991), a standardized parent-rating scale with strong psychometric properties. No significant between-group differences were detected on any of the behavior problem syndrome scales. Group differences approached significance for the individual items "screams a lot" and "teases a lot" (VN group > Controls). The VN group scored significantly higher than the controls on the "Social Scale," a compilation of positive ratings of the child's social activity, frequency of contacts with friends, behavior with others, and behavior by themselves. Observed outcomes were consistent with previous characterizations of children with VN as "outgoing" or "extroverted" but were not consistent with other claims that this population may be at risk for "aggressive," "attentional," or "impulsive" behavior problems.     

Synthesis,electrical and thermal properties of Bi4V2−xMexO11 (Me=Nb,Zr, Y and Cu with x = 0.0 and 0.06) ceramics

Polycrystalline ceramic samples of Bi₄V_2?xMe_xO₁₁ (Me=Nb, Zr, Y and Cu and x = 0.0 and 0.06) have been synthesized by standard solid state reaction method using high purity oxides. The formation of the compounds have been analysed by X-ray diffraction method. The dielectric constant, dielectric loss and AC conductivity as a function of frequency and temperature have been measured. The dielectric studies indicate that the material is highly lossy, and hence, its AC conductivity increases with the increase of temperature. The DC conductivity of material has been measured as a function of temperature from room temperature to 723 K and its activation energy was calculated using the relation σ = σ ₀exp (?E _a/kT). The modulated differential scanning calorimetry has been used to investigate the effect of substitution on the phase transition (heat capacity and heat flow) of the compounds. The results are discussed in detail.     

The Benzylperoxyl Radical as a Source of Hydroxyl and Phenyl Radicals

The benzyl radical ( 1 ) is a key intermediate in the combustion and tropospheric oxidation of toluene. Because of its relevance, the reaction of 1 with molecular oxygen was investigated by matrix‐isolation IR and EPR spectroscopy as well as computational methods. The primary reaction product of 1 and O₂ is the benzylperoxyl radical ( 2 ), which exists in several conformers that can easily interconvert even at cryogenic temperatures. Photolysis of radical 2 at 365 nm results in a formal [1,3]‐H migration and subsequent cleavage of the O?O bond to produce a hydrogen‐bonded complex between the hydroxyl radical and benzaldehyde ( 4 ). Prolonged photolysis produces the benzoyl radical ( 5 ) and water, which finally yield the phenyl radical ( 7 ), CO, and H₂O. Thus, via a sequence of exothermic reactions 1 is transformed into radicals of even higher reactivity, such as OH and 7 . Our results have implications for the development of models for the highly complicated process of combustion of aromatic compounds.     

Ro-vibrational spectroscopy of molecules represented by a Tietz–Hua oscillator potential

Accurate low and high-lying bound states of Tietz–Hua oscillator potential are presented. The radial Schrödinger equation is solved efficiently by means of the generalized pseudospectral method that enables optimal spatial discreti zation. Both $\ell =0$ and rotational states are considered. Ro-vibrational levels of six diatomic molecules viz., H $_2$ , HF, N $_2$ , NO, O $_2$ , O $_2^+$ are obtained with good accuracy. Most of the states are reported here for the first time. A detailed analysis of variation of eigenvalues with $n, \ell $ quantum numbers is made. Results are compared with literature data, wherever possible. These are also briefly contrasted with the Morse potential results.     

Probing the Binding of Syzygium-Derived α-Glucosidase Inhibitors with N- and C-Terminal Human Maltase Glucoamylase by Docking and Molecular Dynamics Simulation

Human maltase glucoamylase (MGAM) is a potent molecular target for controlling post prandial glucose surplus in type 2 diabetes. Binding of small molecules from Syzygium sp. with α-glucosidase inhibitory potential in MGAM has been investigated in silico. Our results suggest that myricetin was the most potent inhibitor with high binding affinity for both N- and C-terminals of MGAM. Molecular dynamics revealed that myricetin interacts in its stretched conformation through water-mediated interactions with C-terminal of MGAM and by normal hydrogen bonding with the N-terminal. W1369 of the extended 21 amino acid residue helical loop of C-terminal plays a major role in myricetin binding. Owing to its additional sugar sites, overall binding of small molecules favours C-terminal MGAM.     

Effect of ammonia,ammonia-water,and sulfuric acid on the HO2 + HO2 → H2O2 + 3O2 reaction in troposphere: Competition between stepwise and one-step mechanisms

A detailed theoretical study on the reaction mechanisms for the formations of H₂O₂ + ³O₂ from the self-reaction of HO₂ radicals under the effect of NH₃, H₃N···H₂O, and H₂SO₄ catalysts was performed using the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ method. The rate constant was computed using canonical variational transition state theory (CVT) with small curvature tunneling (SCT). Our results indicate that NH₃-, H₃N···H₂O-, and H₂SO₄-catalyzed reactions could proceed through both one-step and stepwise routes. Calculated rate constants show that the catalyzed routes in the presence of the three catalysts all prefer stepwise pathways. Compared to the catalytic efficiency of H₂O, the efficiencies of NH₃, H₃N···H₂O, and H₂SO₄ are much lower due to their smaller relative concentrations. The present results have provided a definitive example of how basic and acidic catalysts influence the atmospheric reaction of HO₂ + HO₂ → H₂O₂ + ³O₂. These results further encourage one to consider the effects of basic and acidic catalysts on the related atmospheric reactions. Thus, the present investigation should have broad implications in the gas-phase reactions of the atmosphere.