Synthesis, spectroscopic characterization, insulin-enhancment, and competitive DNA binding activity of a new Zn(II) complex with a vitamin B6 derivative--a new fluorescence probe for Zn(II)

This paper describes the activity of a Schiff base ligand, derived from pyridoxal, as a promising fluorescence probe for biologically important Zn(II) ion sensing. This is the first report of a vitamin based ligand as a fluorescent probe for sensing Zn(II) ions. The Schiff base H(2)pydmedpt, derived from the condensation of pyridoxal (pyd) and N,N-bis[3-aminopropyl]methylamine (medpt), exhibits around a 325-fold increase in fluorescence quantum yield due to zinc triggered fluorescence switching. The response is specific for Zn(II) ions, and remains unaffected by the presence of alkali and alkaline earth metals but is suppressed to varying degrees by transition metal ions. The corresponding Zn(II)-complex, [Zn(pydmedpt], is isolated. The DFT optimized structure of the complex is compatible with elemental analysis, mass spectrometry, FT-IR, electronic and NMR spectra. The isolated complex, having pK(a) values of ～5.3 and ～5, is a moderate intercalator for DNA with an apparent binding constant of 2.3 × 10(6) M(-1). The complex also shows insulin-enhancing activity at par with other reported complexes, with an IC(50) value of 0.65 with respect to ZnSO(4).     

Study of Neutron-Rich Hypernuclei by the (π −, K +) Reaction at J-PARC

We are planning to perform an experiment at J-PARC and produce new neutron-rich Λ hypernuclei by using the (π ^?, K ⁺) reaction (J-PARC E10). As the first step, we are planning to produce ${^6_{\Lambda}{\rm H}}$ hypernuclei with a ⁶Li target. To conduct this experiment, we are developing new detectors, those are scintillating fiber tracker, and silicon strip detector, for high rate operation to aim at increasing beam intensity up to 10⁷/spill. As a result of beam test in Jun 2012, we are going to use high-rate beam at least 10⁷/spill.     

Simultaneous separation of mercury and lignosulfonate from aqueous solution using supported liquid membrane

This paper presents an experimental investigation on facilitated and simultaneous transport of mercury and lignosulfonate (LS) through a flat sheet supported liquid membrane (SLM) having Nylon 6,6 as support, trioctylamine (TOA) as carrier and dichloroethane as solvent. The experiments were performed at various operating conditions such as strip phase concentration, feed pH, carrier concentration and feed concentration to find the best set of parameters that would yield the maximum separation of pure mercury as well as its mixture with LS. The experiments were performed in co-transport mode using NaOH as the strip phase. It was observed that extraction of mercury as well as its mixture increases with increase in concentration of NaOH up to a certain limit 0.1 M NaOH in case of pure solution and 0.2 M NaOH in case of mixture). Feed phase pH significantly affects the mercury separation process. However, initial feed concentration does not affect the extraction process appreciably. Separation of mixture of mercury and LS behaves in a similar way as their pure solution; however the extraction is low in comparison to pure solution. The extraction of mercury from its pure solution is about 81% in 1 h. The extraction of mercury and LS from their mixture is about 52.6% and 50.2%, respectively at optimum condition and in a period of 2 h.     

Characterization and growth of CdS nanoparticles by a cost effective chemical reduction method

A simple chemical reduction method is followed to grow CdS nanoparticles at room temperature with different duration of time. The grown samples are ultrasonicated in ethanol. The dispersed samples are characterized using electron diffraction techniques. Simultaneously optical absorption, photoluminescence and longtime photorelaxation of these samples are studied at room temperature. An increase in band gap is observed in each case as compared to bulk CdS. Also particle size increases with increase of growth time and hence there is decrease of band gap with increase of growth duration. Simultaneously long time relaxation increases with increase of growth time. An attempt is made to correlate the structural, optical, electrical and opto‐electrical properties. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Gamma irradiation route to synthesis of highly re-dispersible natural polymer capped silver nanoparticles

Aqueous dispersions of highly stable, redispersible silver nanoparticles (Ag NPs) were synthesized using gamma radiolysis with gum acacia as a protecting agent. The formation of nanosized silver was confirmed by its characteristic surface plasmon absorption peak at around 405 nm in UV–vis spectra. The size of the silver nanoparticles can be tuned by controlling the radiation dose, ratio of gum acacia to silver ions and also the ionic strength of the medium. Dynamic light scattering (DLS) measurement of the as-synthesized nanoparticles indicated the size less than 3 nm at higher dose of radiation and this also corroborated the size measurement from the width of the corresponding X-ray diffraction (XRD) peak. The face centered cubic (fcc) crystallinity of the nanoparticles was evident from XRD and high resolution transmission electron microscopic (HRTEM) measurements. Fourier transform infra-red (FTIR) spectroscopic data indicate a bonding of Ag NPs with COO^? group of acacia through bridging bidentate linkage.     

Prediction of mass transfer coefficient in rotating bed contactor (Higee) using artificial neural network

The feasibility of drastically reducing the contactor size in mass transfer processes utilizing centrifugal field has generated a lot of interest in rotating packed bed (Higee). Various investigators have proposed correlations to predict mass transfer coefficients in Higee, but, none of the correlations was more than 20–30% accurate. In this work, artificial neural network (ANN) is employed for predicting mass transfer coefficient data. Results show that ANN provides better estimation of mass transfer coefficient with accuracy 5–15%.     

Cu (II) and Co (II/III) complexes of N,O‐chelated Schiff base ligands: DNA interaction,protein binding,cytotoxicity, cell death mechanism and reactive oxygen species generation studies

A series of copper (II) ( 1 and 3 ) and cobalt (II/III) ( 2 , 4 and 5 ) complexes comprising different imino‐phenolate ligands DCH , DTH and DBH ₂ (where DCH = 2,4‐dichloro‐6‐((mesitylimino)methyl)phenol, DTH = 2,4‐di‐tert‐butyl‐6‐((mesitylimino)methyl) phenol and DBH ₂ = 2,4‐dibromo‐6‐((mesitylimino)methyl)phenol) have been prepared with excellent yield and high purity. By utilizing different spectroscopic tools such as UV–visible, electrospray ionization (ESI)‐mass, Fourier‐transform infrared (FTIR) spectrometry and elemental analysis, the prepared complexes ( 1 – 5 ) were thoroughly characterized. The molecular structure of the synthesized complexes was ascertained by using single‐crystal X‐ray diffraction studies (SCXRDs). The experiment reveals that Complexes 1 – 5 bind to calf thymus DNA (CT‐DNA) through non‐intercalative way with good interacting abilities. However, 1 – 5 are excellent quenchers of the fluorescence intensity of bovine serum albumin (BSA) following the static pathway. Additionally, they had shown remarkable cytotoxic potential against MCF‐7 (mammary gland adenocarcinoma) and A549 (lung adenocarcinoma) cell lines. The IC₅₀ values associated with these complexes were much lower than the conventional drug cisplatin. Apoptosis‐induced cell death was confirmed from the DNA fragmentation studies and Hoechst 33342 staining. The 2′,7′‐dichlorofluorescein diacetate (DCFDA) assay indicates that the complex mediated reactive oxygen species (ROS) generation is accountable for governing the apoptosis mechanism via oxidative cell distress. Apart from these studies, by carrying out density functional theory (DFT) method, highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) energy gap calculations and optimized structures of the synthesized complexes were accomplished.     

Chemical Composition and Antioxidant Activity of the Leaf Essential Oil of Schefflera venulosa

Chemistry of Natural Compounds -