Preparation of perinones via a novel multicomponent synthesis of isoindole scaffold

A convenient procedure for the preparation of isoindole derivatives is described. The method is based on the multicomponent reaction of heterocyclic ketene aminals with dialkyl acetylenedicarboxylates in presence of DMAP. The reaction is very simple from an experimental point of view and allows the creation of a fused isoindole moiety with concomitant formation of benzene and pyrrole ring in a single operation.     

The simple radiochemical determination of 90Sr in environmental solid samples by solvent extraction

Determination of ⁹⁰Sr in environmental solid samples is a challenging task because of the presence of so many other radionuclides in samples of interest. This problem was dealt with by radiochemical separation of strontium followed by yttrium separation and Cerenkov counting of the high-energy ??-particle emissions of ⁹⁰Y in order to quantitate ⁹⁰Sr. In this work, an improved method is described for the determination of ⁹⁰Sr in soil samples, through the separation of the daughter ⁹⁰Y at equilibrium. The procedure is based on the HDEHP solvent extraction in combination with liquid scintillation spectrometry (LSS). A low background Quantulus has been optimized for low level counting of Cerenkov radiation emitted by the hard ??-emitter ⁹⁰Y. The analytical quality of the method has been checked by analyzing IAEA Soil-375 reference materials. The analytical method has also been successfully applied to the determination of ⁹⁰Sr for moss-soil samples in inter-laboratory exercises through IAEA??s ALMERA network. The chemical recovery for ⁹⁰Y extraction ranged from 80 to 85% and the counting efficiency was 73% in the window 25?C400 keV.     

Interaction of Mitomycin C with DNA Immobilized onto Single‐walled Carbon Nanotube/Polymer Modified Pencil Graphite Electrode

The electrochemical investigation of the interaction between the anticancer drug mitomycin C (MC) and DNA was described using a single‐walled carbon nanotube (SWCNT)/poly(vinylferrocenium) (PVF⁺) modified pencil graphite electrode (PGE). The electrochemical oxidation signals of guanine were monitored before and after the interaction between MC and DNA by using differential pulse voltammetry. The effects of DNA and MC concentration and MC interaction time were examined based on the electrode response. Cyclic voltammetry and electrochemical impedance spectroscopy were used for the characterization of SWCNT/PVF⁺ modified and PVF⁺ modified PGEs. The detection limit corresponded to 625 ng/mL for MC using calf thymus double‐stranded DNA immobilized SWCNT/PVF⁺ modified PGE.     

Preparation and characterization of zinc oxide nanoparticles and their sensor applications for electrochemical monitoring of nucleic acid hybridization

The interaction of PLGA-chitosan Nanoplexes with ocular mucosa was investigated ex vivo and in vivo to assess their potential as ocular delivery system. Fluorescent Rhodamine Nanoplexes (Rd-Nanoplexes) were prepared by ionotropic gelation method. The size and morphology of Nanoplexes was investigated by TEM, SEM and PCS. The corneal retention, uptake and penetration of Nanoplexes were analyzed by spectrofluorimetry and confocal microscopy. Corneas from Rd-Nanoplexes-treated rabbits were evaluated for the in vivo uptake and ocular tolerance. The Nanoplexes prepared were round with a mean diameter of 115.6±17nm and the encapsulation efficiency of Rd was 59.4±2.5%. Data from ex vivo and in vivo studies showed that the amounts of Rd in the cornea were significantly higher for Nanoplexes than for a control Rd solution, these amounts being fairly constant for up to 24h. Confocal microscopy of the corneas revealed paracellular and transcellular uptake of the Nanoplexes. The uptake mechanism postulated was adsorptive-mediated endocytosis and opening of the tight junctions between epithelial cells. No alteration was microscopically observed after ocular surface exposure to Nanoplexes. Taken together, these data demonstrate that Nanoplexes are potentially useful as ocular drug carriers.     

Solid phase extraction and determination of nickel in water samples by using novel thiol-containing sulfonamide polymeric resin and atomic absorption spectrophotometer

Interest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry as well as the high costs of other sensitive methods in compared to flame atomic absorption spectrometry.In this study,thiol-containing sulfonamide resin was synthesized,characterized and applied as a new sorption material for solid phase extraction of nickel in drinking water samples.After preconcentration procedure,flame atomic absorption spectrometry was used for determinations.Optimum parameters were found to be pH=3.2,contact time =20 min and eluate volume=3 mL.The limit of detection was found to be 0.75 ng · mL-1.The synthesized resin exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent,high sorption capacity as well as the relatively fast extraction rate.The Ni concentrations in the studied 21 kind of water samples were found to be in the range of BDL-4.0 ng ·mL-1.     

Poly(vinyl trimethylsilane) and block copolymers of vinyl trimethylsilane with isoprene: Anionic polymerization, morphology and gas transport properties

Poly(vinyl trimethylsilane) (PVTMS) and block copolymers of vinyl trimethylsilane with isoprene were synthesized by anionic polymerization and characterized. The synthesized pure PVTMS has properties similar to a reference material produced about two decades ago and can be used for thin film composite membrane formation. Even at low isoprene content the block copolymers have improved film forming properties compared to the pure PVTMS. However, the presence of the isoprene units in the block copolymers leads to a decrease of the gas permeability but does not affect the selectivity of the membranes (α(O₂/N₂) = 3.9).     

Preparation of a portable point-of-care in vitro diagnostic system, for quantification of canine C-reactive protein, based on a magnetic two-site immunoassay

In this study, characterization of the binding kinetics and optimization of a magnetic permeability based point-of-care (POC) immunoassay system for quantification of canine C-reactive protein (cCRP) is described. The reagent is based on a two-site heterogeneous immunoassay system utilizing conjugated superparamagnetic nanoparticles (SPION) and silica particles, both particles carrying covalently linked antibodies directed to the cCRP analyte. Detection is carried out using a magnetic permeability-based small instrument, adjusted in order to apply it in a POC setting near the patients. The kinetic parameters are characterized and applied in the final design of the assay system. In the cCRP system studied, 90 % of the binding between immobilized solid-phase silica antibody and cCRP is complete after only 15 s, and 30 s for the binding between the antibody on the SPION and the bound cCRP on the silica particle. Additionally, the binding rate constants are determined to be 149 and 30 M^?1s^?1, respectively. The analytical sensitivity, clinical sensitivity, and imprecision verifies the clinical usefulness of the system. Also, quantification of cCRP, using the system described, in dog clinical samples from mixed breeds shows a high correlation to a commercially available comparative cCRP ELISA system (y?=?0.98?×?+3.2, R ²?=?0.98, n?=?47). The immunoassay system described can thus provide the veterinarian a valuable tool for rapid diagnosis and monitoring of inflammatory diseases in dogs in a setting near the patients.     

A practical approach for generation of WO3-based flexible electrochromic devices

Journal of Solid State Electrochemistry - We managed to provide one-step facile electrochromic device (ECD) preparation to incorporate two cathodic coloring components into lithium ion (Li+)-doped...     

Use of aminoprophyl silica-immobilized humic acid for Cu(II) ions removal from aqueous solution by using a continuously monitored solid phase extraction technique in a column arrangement

Humic acid (HA) which originated from Leonardite was purified and immobilized onto aminoprophyl silica (APS). Afterwards, the remaining amino groups on the silica are successfully end-capped using acetic anhydride in DMF media and this material was used for Cu(II) ions removal from aqueous solution by using continuously solid phase extraction (SPE) technique in a column arrangement. The sorption characteristics of Cu(II)-immobilized humic acid (ImHA) system were investigated at various experimental conditions, and output was observed by a UV detector. All solid phase extraction (SPE) steps were monitored through breakthrough curves used to visualize distribution of Cu(II) concentration between mobile phase and solid phase. In addition to this, the solutions collected from stripping steps were analyzed in atomic absorption spectrophotometry (AAS) and the amount of adsorbed Cu(II) ions was calculated. It was found that there was a high correlation (R² = 1) between the peak area and AAS data of stripping steps. Sorption characteristics were evaluated by using Freundlich, Langmuir, and Dubinin–Radushkevich (D-R) adsorption isotherms, as well as by Scatchard plot analysis. Thus, the sorption characteristics and usability of ImHA as a solid phase for SPE of Cu(II) ions was evaluated in detail. From the obtained results, it was seen that sorption mechanism of Cu(II) fits to Langmuir model on a large scale, sorption was thought to be localized. From D-R isotherm mean free energy of sorption (E) was calculated (17.68 kJ mol⁻¹), and it was deduced that chemical interactions were more effective than physical interactions for Cu(II). This investigation provides a new, environmentally friendly and cost-effective possibility to remove Cu(II) ions from aqueous solution by using the new APS-ImHA material.     

Indicator-based and indicator-free magnetic assays connected with disposable electrochemical nucleic acid sensor system

An indicator-based and indicator-free magnetic assays connected with a disposable pencil graphite electrode (PGE) were successfully developed, and also compared for the electrochemical detection of DNA hybridization. The oxidation signals of echinomycin (ECHI) and electroactive DNA bases, guanine and adenine, respectively were monitored in the presence of DNA hybridization by using differential pulse voltammetry (DPV) technique. The biotinylated probe was immobilized onto the magnetic beads (magnetic particles, microspheres) and hybridization with its complementary target at the surface of particles within the medium was exhibited successfully using electrochemical sensor system. For the selectivity studies, the results represent that both indicator-based and indicator-free magnetic assays provide a better discrimination for DNA hybridization compared to duplex with one-base or more mismatches. The detection limits (S/N = 3) of the magnetic assays based on indicator or indicator-free were found in nM concentration level of target using disposable sensor technology with good reproducibility. The characterization and advantages of both proposed magnetic assays connected with a disposable electrochemical sensor are also discussed and compared with those methods previously reported in the literature.