Chemical Composition of Essential Oil from Pilea microphylla and its Antimicrobial Activity

Chemistry of Natural Compounds -     

Lossy mode resonance-based uniform core tapered fiber optic sensor for sensitivity enhancement

A lossy mode resonance (LMR)-supported fiber optic sensor in which a uniform fiber core is placed among two identical tapered regions, is investigated numerically. Indium tin oxide (ITO) and aluminum-doped zinc oxide (AZO) are considered as LMR active materials used to excite several lossy modes and gold and silver are used as surface plasmon resonance (SPR) active materials. In this probe design, a central uniform core coated with ITO/AZO is the active sensing region, whereas tapered regions are meant for bringing the incident angle close to the critical angle. The sensitivity of the present fiber optic bio-sensor is evaluated for first two LMRs utilizing both ITO and AZO separately, along with its variation with the taper ratio (TR). For ITO, the maximum sensitivity values are observed to be 18.425 μm RIU⁻¹ (refractive index unit) and 0.825 μm RIU⁻¹, corresponding to the first and second LMRs, respectively, at a TR of 1.6 and for AZO, equivalent values are 0.79 μm RIU⁻¹ and 0.35 μm RIU⁻¹, respectively, at a TR of 2.0. The results illustrate that the first LMR is more sensitive than the second LMR and the ITO-coated probe possesses greater sensitivity than the AZO-coated probe for both LMRs. Similarly, for the fiber optic SPR sensor, the maximum value of sensitivity is 5.6425 μm RIU⁻¹, in the case of gold and 5.0615 μm RIU⁻¹ in the case of silver, at a TR of 1.6. Hence, the result shows that the sensor with the present fiber optic probe design has around a 3-fold enhancement in sensitivity compared with conventional SPR sensors. This study will have applications in many sensing schemes where the requirement of large sensitivity is vital.     

Decay of Hot and Rotating $${}^{\boldsymbol{88}}$$ Mo $${}^{\boldsymbol{*}}$$ at Incident Energies of 300, 450, and 600 MeV

Physics of Atomic Nuclei - The reaction mechanism for the decay of the hot and rotating compound system $${}^{88}$$ Mo $${}^{*}$$ formed in $${}^{48}\textrm{Ti}+^{40}$$ Ca reaction and the time for...     

Transition-Metal-Free Reverse Reactivity of (2-Alkynyl)-Arylaldimines: Assembly of Functionalized Amino-Indinones

Transition-metal-free regioselective synthesis of functionalized amino-indenones by the reaction of ortho-alkynylaldehydes with a broad range of primary amines by intramolecular cyclization has been described. The designed reaction proceeds through KOH-mediated Prins-type cyclization and DMSO-promoted oxidation of the cyclopent-2-en-1-one system. The proposed mechanism and role of solvent were well supported by control experiments. For the first time, we have disclosed the reverse reactivity of (2-alkynyl)-arylaldimines in a super basic system.     

How does a hydrocarbon staple affect peptide hydrophobicity?

Water is essential for the proper folding of proteins and the assembly of protein–protein/ligand complexes. How water regulates complex formation depends on the chemical and topological details of the interface. The dynamics of water in the interdomain region between an E3 ubiquitin ligase (MDM2) and three different peptides derived from the tumor suppressor protein p53 are studied using molecular dynamics. The peptides show bimodal distributions of interdomain water densities across a range of distances. The addition of a hydrocarbon chain to rigidify the peptides (in a process known as stapling) results in an increase in average hydrophobicity of the peptide–protein interface. Additionally, the hydrophobic staple shields a network of water molecules, kinetically stabilizing a water chain hydrogen‐bonded between the peptide and MDM2. These properties could result in a decrease in the energy barrier associated with dehydrating the peptide–protein interface, thereby regulating the kinetics of peptide binding. © 2015 Wiley Periodicals, Inc.     

Improvement in the yield and quality of kalmegh (Andrographis paniculata Nees) under the sustainable production system

Andrographis paniculata Nees is an annual erect herb with wide medicinal and pharmacological applications due to the presence of andrographolide and other active chemical constituents. The large-scale cultivation of the kalmegh is not in practice. The aim of this study was to establish sustainable production systems of A. paniculata cv CIM-Megha with the application of different bioinoculants and chemical fertilisers. A. paniculata herb and andrographolide yield in the dried leaves was found to be highest (218% and 61.3%, respectively) in treatment T₃ (NPK+Bacillus sp.) compared with T₁ (control). The soil organic carbon, soil microbial respiration, soil enzymes activity and available nutrients improved significantly with combined application of bioinoculants and chemical fertilisers.     

Cytotoxic agents for KB and SiHa cells from n-hexane fraction of Cissampelos pareira and its chemical composition

Eleven constituents were characterised by gas chromatography–mass spectrometry analysis, and five molecules were isolated using column chromatography. The in vitro study of the extract and isolated molecules against KB and SiHa cell lines revealed oleanolic acid (1) and oleic acid (2) as potent cytotoxic molecules with potential anticancer activity. The IC₅₀ values of n-hexane extract (CPHF), oleanolic acid (1) and oleic acid (2) were >300, 56.08 and 70.7 μg/mL (μM), respectively, against KB cell lines and >300, 47.24 and 80.2 μg/mL (μM), respectively, against SiHa cell lines.     

Enhancement of electrical conductivity,director relaxation frequency and slope of electro-optical characteristics in the composites of single-walled carbon nanotubes and a strongly polar nematic liquid crystal

In the present work, single-walled carbon nanotubes (SWCNTs) were dispersed in a room temperature nematic liquid crystal 4-pentyl-4′-cyanobiphenyl at the concentration of 0.02 and 0.05 wt%. Differential scanning calorimetry and temperature-dependent dielectric studies suggest decrease in clearing temperature of the composite materials as compared to the pure material. Ionic conductivity increases by two orders of magnitude due to the dispersion of such a low concentration (0.05 wt%) of SWCNTs. Dielectric studies also show that the presence of the SWCNTs decreases the effective longitudinal as well as transverse components of the dielectric permittivity. For homeotropic aligned samples, a relaxation mechanism has been detected in the lower MHz region both for the pure as well as dispersed samples. Presence of SWCNTs increases the relaxation frequency corresponding to flip-flop motion of molecules around their short axes. From frequency-dependent dielectric studies, important dielectric parameters such as relaxation frequency, dielectric strength and distribution parameters have been determined. Electro-optical experiments show that the threshold voltage decreases and the steepness of the transmission voltage curve improves due to the dispersion of SWCNTs.     

Hydromagnetic flow due to torsional oscillations of an infinite disk about a steady non-zero mean

The present investigation is the study of the laminar hydromagnetic flow due to torsional oscillations of an infinite disk about a steady non-zero mean in an electrically conducting fluid. Separate solutions have been obtained for the limiting cases of low and high frequency oscillations. The low frequency solution is obtained by expressing the flow functions in powers (ik) while for high frequencies, the flow functions are expressed in powers of $\text{(ik)}{}^{\mathrm{<mtext>?</mtext><mtext>1</mtext><mtext>2</mtext>}}$, where $\text{k =}\text{ω}\text{Ω}$ being the ratio of the frequency of oscillations ω to the mean disk-angular velocity Ω and i² = ?1. It is found that the oscillating part of the transverse shearing stress has a phase-lead while that of the radial shearing stress has a phase lag behind the disk oscillations. The phase-lead in the former case and phase-lag in the latter case decrease with the increase in the strength of the applied magnetic field.