Synthesis and characterization of a new class of heteronuclear derivatives of zirconium(IV)

Reactions of Zr{Al(OPrⁱ)₄}₂Cl₂ or Zr{Nb(OPrⁱ)₆}₂Cl₂ with KNb(OPrⁱ)₆/KAl(OPrⁱ)₄ and diethanolamines RN(CH₂CH₂OH)₂ [R=H(L^HH₂), Me(L^MeH₂), and Ph(L^PhH₂)] in the presence of two equivalents of Et₃N yield interesting hetero(bi- and tri-) nuclear derivatives (1)–(8) All of these new derivatives have been characterized by elemental analyses, molecular weight measurements, and spectroscopic studies.Ram C. Mehrotra - Deceased     

Nonuniform Multiwavelet Sets and Multiscaling Sets

In this article, we study the theory of nonuniform minimally supported frequency multiwavelets and nonuniform multiscaling sets. A characterization of nonuniform multiwavelet sets is obtained which generalizes a result of Yu and Gabardo. After introducing a notion of generalized nonuniform scaling set, we obtain a characterization of nonuniform multiscaling sets associated with nonuniform multiresolution analysis having finite multiplicity. In addition, we provide a geometric construction to find families of symmetric nonuniform multiwavelet sets.     

Adjuvants Based on Hybrid Antibiotics Overcome Resistance in Pseudomonas aeruginosa and Enhance Fluoroquinolone Efficacy

The use of adjuvants that rescue antibiotics against multidrug‐resistant (MDR) pathogens is a promising combination strategy for overcoming bacterial resistance. While the combination of β‐lactam antibiotics and β‐lactamase inhibitors has been successful in restoring antibacterial efficacy in MDR bacteria, the use of adjuvants to restore fluoroquinolone efficacy in MDR Gram‐negative pathogens has been challenging. We describe tobramycin–ciprofloxacin hybrid adjuvants that rescue the activity of fluoroquinolone antibiotics against MDR and extremely drug‐resistant Pseudomonas aeruginosa isolates in vitro and enhance fluoroquinolone efficacy in vivo. Structure–activity studies reveal that the presence of both tobramycin and ciprofloxacin, which are separated by a C12 tether, is critical for the function of the adjuvant. Mechanistic studies indicate that the antibacterial modes of ciprofloxacin are retained while the role of tobramycin is limited to destabilization of the outer membrane in the hybrid.     

Magnetic beads-based immunoassay as a sensitive alternative for atrazine analysis

A new immunoassay strategy for sensitive atrazine determination based on magnetic beads is reported. The immuno-method is a competitive solid-phase immunoassay where the anti-atrazine antibody is immobilized on the magnetic beads surface and fixed at the reaction cell bottom using a simple magnet, which generates a magnetic field. Analyte and HRP (horseradish peroxidase) tracer compete for active sites of antibody. After the immunointeractions antibody-analyte and antibody-tracer, atrazine quantification from the sample is performed by injection of the chemiluminescence substrate (luminol, hydrogen peroxide and p-iodophenol). Different antibodies (polyIgG anti-atrazine Ab I and affinity purified polyIgG anti-atrazine AbI) were tested in this configuration. Also, optimum concentration of antibody-covered magnetic beads was set up (8 mg/l Ab II). Finally, the performance of magnetic beads-based immunoassay for atrazine determination was evaluated demonstrating that the magnetic beads-based immunoassay is one of the most sensitive method for atrazine determination (LoD = 3 pg/l, IC₅₀ = 37 pg/l, DR = 10-1000 pg/l).     

Rhodium Fluoroapatite Catalyzed Conjugate Addition of Arylboronic Acids to α,β‐Unsaturated Carbonyl Compounds

Rhodium fluoroapatite (RhFAP) is an efficient catalyst for conjugate addition of organoboron reagents to α,β‐unsaturated carbonyl compounds. A variety of arylboronic acids and α,β‐unsaturated carbonyl compounds were converted to the corresponding conjugate‐addition products, demonstrating the versatility of the reaction. The reaction is highly selective. RhFAP was recovered quantitatively by simple filtration, and reused for four cycles.     

Building switchable peptide-architectures on gold/composite surfaces: New perspectives in electrochemical bioassays

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Supramolecular Copolymerization as a Strategy to Control the Stability of Self‐Assembled Nanofibers

A major challenge in supramolecular polymerization is controlling the stability of the polymers formed, that is, controlling the rate of monomer exchange in the equilibrium between monomer and polymer. The exchange dynamics of supramolecular polymers based on benzene‐1,3,5‐tricarboxamide (BTA) can be regulated by copolymerizing molecules with dendronized (dBTA) and linear (nBTA) ethylene glycol‐based water‐soluble side chains. Whereas nBTAs form long nanofibers in water, dBTAs do not polymerize, forming instead small spherical aggregates. The copolymerization of the two BTAs results in long nanofibers. The exchange dynamics of both the BTA monomers in the copolymer are significantly slowed down in the mixed systems, leading to a more stable copolymer, while the morphology and spectroscopic signature of the copolymers are identical to that of nBTA homopolymer. This copolymerization is the supramolecular counterpart of styrene/ maleic anhydride copolymerization.     

Paper-based diagnostic platforms and devices

Paper-based analytical devices have become lately “must have” components in equipment and instrumental designed for point-of-care applications, especially when they are used in tandem with microfluidic platforms. Nowadays, paper-based electrochemical devices (PEDs) represent the first choice in the development of lab-on-a-chip biosensors because of their benefits in biomedical diagnosis in terms of simplicity, affordability, portability, and disposability. Moreover, cellulose is a biodegradable and biocompatible substrate, ideal for building disposable devices for use in remote locations or low-resource settings. Despite their low costs and simplicity, PEDs must face a tough challenge—meeting the affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to end users criteria. The latest achievements in microfluidic PEDs for clinical diagnosis will be critically discussed, putting emphasis on innovative assay formats and methods for surface modification.     

Bioremediation of PCB-contaminated sediments and evaluation of their pre- and post-treatment ecotoxicity

The paper deals with the application of two perspective and promising bioremediation approaches, bioaugmentation and biostimulation, applied to sediment contaminated with polychlo-rinated biphenyls (PCBs) with the aim to enhance biodegradation of PCBs. Sediments were sampled from Strá?sky canal, an industrial waste canal that flows from a former PCB-factory through the Laborec river into the Zemplínska ?írava water reservoir, all located in the eastern part of Slovakia. Bioaugmentation of sediments was performed in microcosms using two bacterial isolates with PCB-degradation ability obtained from the contaminated sediment: Achromobacter xylosoxidans, Stenotrophomonas maltophilia. Biostimulation was performed using an addition of cut plants containing terpenes, known as PCB-inducers (ivy leaves and pine needles). Ecotoxicity of the contaminated sediments was evaluated pre- and post-treatment using biotests of the standard aquatic plant Lemna minor, standard contact test using Lactuca sativa var. capitata, and the bioluminescent bacteria Vibrio fischeri. Biostimulation treatment using ivy leaves revealed higher degradation of detected PCB congeners than that achieved by the addition of pine needles, but moderately higher post-treatment toxicity of the sediment to the bioindicator Lemna minor.