The Use of an Electroactive Marker as a SERS Label in an E‐melting Mutation Discrimination Assay

In this paper we describe the first example of the use of an electroactive label as a SERS marker for detecting and quantifying target oligonucleotides and distinguishing mutations using a combination of voltammetry and electrochemically induced melting (E‐melting). The experiments were carried out on sphere segment void substrates selected to show strong surface enhancement for SERS at 633 nm. DNA analysis was carried out for CFTR sequences using synthetic 22‐mer oligonucleotides labelled with a modified anthraquinone at the 3′‐end. Discrimination between the wild type, 1653C/T (point mutation) and ΔF508 (triple deletion) is demonstrated.     

Synthesis and characterization of novel pyridyl/naphthyl/(diphenyl)methylseleno substituted alkanoic acids: X-ray structure of 2-pyridylselenoethanoic acid, 2-naphthylselenoethanoic acid and 2-(diphenyl)methylselenoethanoic acid

A number of novel and synthetically important pyridyl/naphthyl/(diphenyl)methylseleno substituted alkanoic acids (20-25) have been synthesized using an efficient and operationally simple strategy. Starting substrates, ethyl pyridyl/naphthyl/(diphenyl)methylseleno substituted alkanoates (8-13) were easily prepared by treatment of ethyl chloroalkanoates 7(a-c) with nucleophilic selenium reagent RSeNa⁺, generated from the cleavage of dipyridyl/dinaphthyl/bis(diphenylmethyl) diselenide (1-6) with sodium borohydride in ethanol. The ethyl pyridyl/naphthyl/(diphenyl)methylseleno substituted alkanoates (8-13) on basic hydrolysis and subsequent acidification afford pyridyl/naphthyl/(diphenyl) methylseleno substituted alkanoic acids (20-25) in excellent yields. These selenoalkanoates (8-13) and selenoalkanoic acids (20-25) have been characterized by elemental analysis and various spectroscopic techniques viz. NMR (¹H, ¹³C and ⁷⁷Se), IR and mass spectrometry. The molecular structure of 2-pyridylselenoethanoic acid (20a), 2-naphthylselenoethanoic acid (23a) and 2-(diphenyl)methylselenoethanoic acid (24a) has also been established with the help of single crystal X-ray analysis.     

Terphenyl based ‘Turn On’ fluorescent sensor for mercury

New terphenyl-based derivative 4 with pyrene as a fluorophore has been synthesized and examined for its cation recognition abilities toward various cations by NMR and fluorescence spectroscopy. The results show that it has very high binding affinity (log β = 5.12) and selectivity for mercury. A fluorescence enhancement of 375% was observed for the 4-Hg²⁺ system in THF. A Hg²⁺ selective electrode (ISE) was also formed which showed excellent selectivity over all the other cations tested. The lower limit of detection is 2.1 × 10⁻⁶ M.     

HPTLC Densitometric Quantification of Hydrolyzable Tannins from Triphala churna

JPC – Journal of Planar Chromatography – Modern TLC - A simple high-performance thin-layer chromatographic (HPTLC) method has been established for simultaneous quantification of...     

Bending and radial deformation of lipid tubules on self-assembled thiol monolayers

Lipid tubules represent a hollow, cylindrical supramolecular structure formed by rolled-up lipid bilayers. We find that the lipid tubules of 1,2-bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine can be bent into a loopike shape by the shrinking contact line of droplets on self-assembled monolayers (SAMs) of 1-dodecanethiol. The persistence length of individual lipid tubules is estimated to be approximately 41 microm. The radial deformation of the lipid tubules on SAMs is studied under applied load using atomic force microscope. The stiffness of the tubules in the radial direction is found to increase when the number of the lipid bilayers in the tubule wall increases.     

Effect of temperature on the unfavorable mixing between tetraethylene glycol dodecyl ether and Pluronic P103

The fluorescence measurements of tetraethylene glycol dodecyl ether (C12E4) and triblock polymer (Pluronic P103), poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), (EO)17(PO)60(EO)17, binary mixtures have been performed over the whole mixing range in the temperature range of 20-40 degrees C. The results have been evaluated by computing various micellar parameters and excimer formation. It has been concluded that mixed micelle formation takes place due to unfavorable mixing at lower temperature range, and the magnitude of which decreases with the increase in temperature up to 40 degrees C. The reduction in the unfavorable mixing has been attributed to the dehydration of P103 micelles with the increase in temperature.     

Easily coupled whispering gallery plasmons in dielectric nanospheres embedded in gold films

A new self-aligned robust method for coupling to whispering gallery modes (WGMs) of submicron microspheres utilizes their periodic arrangement without relying on nanopositioned external coupling devices. The microspheres are embedded in a nanostructured gold surface supporting delocalized plasmonic crystal modes that mediate the coupling, and can be tuned by the geometry. Detailed measurements of the angle- and orientation-dependent reflectivity reveal localized plasmonic WGMs whose energies scale with sphere diameter and agree closely with Mie calculations. Coupling between these plasmonic WGMs leads to mode splitting and the formation of plasmonic minibands of a controllable bandwidth.     

Large piezoresponse of lead-free Bi0.5(Na0.85K0.15)0.5TiO3 thin film

0.85Bi_0.5Na_0.5TiO₃-0.15Bi_0.5K_0.5TiO₃ (BNKT15) lead-free thin films were prepared on Pt(111)/TiO₂/SiO₂/Si(100) substrates by the chemical solution deposition method. BNKT15 are MPB composition in the Bi_0.5Na_0.5TiO₃-Bi_0.5K_0.5TiO₃ (BNT-BKT) system. The maximum piezoelectric coefficient (d_33,f) value of BNKT15 thin film is approximately 75 pm/V, which is comparable to that of polycrystalline PZT thin films. These results suggest that BNKT15 thin film can be used as an alternative for PZT films in piezoelectric micro-electromechanical systems.     

An Efficient and Simple One-Pot Synthesis of Novel 2-Amino-5-aza-6-(dinitrilomethylene)-4,7,7-trimethylbicyclo[2.2.2]octane-1,3-dicarbo-nitrile and its Crystal Structure

Abstract  

The title compound was prepared by the reaction of 4-methyl-pent-3-en-2-one and malononitrile, at room temperature, in the presence of indium-triflate and triethylamine. The structure of the molecule was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the monoclinic space group C2/c with unit cell parameters: a = 14.269 (2), b = 10.141 (2), c = 19.743 (3) ?, β = 95.523(4)°, Z = 8. The crystal structure was solved by direct methods and refined to R = 0.0526 for 2,690 observed reflections. The isoquinuclidine rings adopt boat conformation. The molecules in the unit cell are arranged in layers. The crystal structure is stabilized by N–H⋯N interactions.