DNA binding selectivity of oligopyridine-ruthenium(II)-lysine conjugate

The synthesis, characterization and DNA binding properties of the complex [Ru(terpy)(4,4'-(COLysCONH(2))(2)bpy)Cl](3+) (1) have been studied. Complex (1) hydrolyzes to (2) with a calculated rate constant K(h) = 2.35 ± 0.08 × 10(-4) s(-1) and binds coordinatively to ct-DNA, with a saturation r-value at about 0.1. Stabilization of the ct-DNA helix at low electrolyte (NaClO(4)) concentration (10 mM) and destabilization at higher electrolyte concentrations (50-200 mM) was observed. Circular dichroism studies indicate that the hydrolyzed complex binds to DNA, increasing the unwinding of the DNA helix with an unwinding angle calculated as Φ = 12 ± 2°. The positive LD signal observed at 350 nm indicates some kind of specificity in complex orientation towards the global DNA axis. Complex (2) binds specifically to G4 on the central part of the oligonucleotide duplexes d(CGCGCG)(2) and d(GTCGAC)(2), as evidenced by NMR spectroscopy. Both lysine moieties were found to interact most likely electrostatically with the DNA phosphates, assisting the coordinative binding and increasing the DNA affinity of the complex. Photoinduced DNA cleavage by (2), upon UVA irradiation was observed, but despite its relative high DNA affinity, it was incomplete (~12%).     

Development and validation of an HPLC confirmatory method for the determination of seven tetracycline antibiotics residues in milk according to the European Union Decision 2002/657/EC

An HPLC method with diode-array detection, at 355 nm, was developed and validated for the determination of seven tetracyclines (TCs) in milk: minocycline (MNC), TC, oxytetracycline (OTC), methacycline (MTC), demeclocycline (DMC), chlortetracycline (CTC), and doxycycline (DC). Oxalate buffer (pH 4) was used with 20% TCA as a deproteinization agent for the extraction of analytes from milk followed by SPE. The separation was achieved on an Inertsil ODS-3, 5 microm, 250 x 4 mm(2 )analytical column at ambient temperature. The mobile phase, a mixture of A: 0.01 M oxalic acid and B: CH(3)CN, was delivered using a gradient program. The procedure was validated according to the European Union decision 2002/657/EC determining selectivity, stability, decision limit, detection capability, accuracy, and precision. Mean recoveries of TCs from spiked milk samples (50, 100, and 200 ng/g) were 93.8-100.9% for MNC, 96.8-103.7% for OTC, 96.3-101.8% for TC, 99.4-107.2% for DMC, 99.4-102.9% for CTC, 96.3-102.7% for MTC, and 94.6-102.1% for DC. All RSD values were lower than 8.5%. The decision limits CC(a) calculated by spiking 20 blank milk samples at MRL (100 microg/kg) ranged from 101.25 to 105.84 microg/kg, while detection capability CC(b )from 103.94 to 108.88 microg/kg.     

Global Solutions to a Model for Exothermically Reacting,Compressible Flows with Large Discontinuous Initial Data

 We prove the global existence of solutions of the Navier-Stokes equations describing the dynamic combustion of a compressible, exothermically reacting fluid, and we study the large-time behavior of solutions, giving necessary and sufficient conditions for complete combustion in certain cases. The adiabatic constants and specific heats of the burned (product) and unburned (reactant) fluids may differ, and the initial data may be large and discontinuous. (Accepted August 31, 2002) Published online January 9, 2003 Communicated by C. M. Dafermos     

High-spin molecules: A mixed-valence Mn6 octahedron with an S = 11 ground state

The employment of 1,1,1-tris(hydroxymethyl)ethane ligand in higher oxidation state Mn cluster chemistry has yielded a new hexanuclear, mixed-valence (II,III,IV) compound with a rare [Mn₆(μ₆-O)]¹⁸⁺ octahedral core. The Mn₆ molecule is completely ferromagnetically coupled and possesses an S = 11 ground state, the maximum for a Mn^II, 2Mn^III, 3Mn^IV species.     

Classification of real hypersurfaces in complex quadric in terms of new tensors

Periodica Mathematica Hungarica - In this paper two new tensor fields on real hypersurfaces in complex quadric are introduced. Real hypersurfaces on which the derivatives of the tensor fields with...     

Semi-parallelism of normal Jacobi operator for Hopf hypersurfaces in complex two-plane Grassmannians

It is proved the non-existence of Hopf hypersurfaces in $G_{2}({\mathbb{C }}^{m+2}), m\ge 3$ , whose normal Jacobi operator is semi-parallel, if the principal curvature of the Reeb vector field is non-vanishing and the component of the Reeb vector field in the maximal quaternionic subbundle $\mathfrak{D }$ or its orthogonal complement $\mathfrak{D } ^{\bot }$ is invariant by the shape operator.     

Phytochemical analysis of young fustic (Cotinus coggygria heartwood) and identification of isolated colourants in historical textiles

Young fustic (Cotinus coggygria Scop.; Anacardiaceae) has been used as a dyestuff since antiquity. Phytochemical investigation of the methanol extract of the heartwood has led to the isolation and structure elucidation by nuclear magnetic resonance and mass spectrometry (MS) of 3′,4′,6-trihydroxyaurone (sulfuretin) and 3′,4′,7-trihydroxyflavonol (fisetin) as well as 3′,4′,7-trihydroxyflavanol (fustin), 3′,4′,5,7-tetrahydroxyflavonol (quercetin), 3′,4′,5,7-tetrahydroxyflavanol (taxifolin), 4′,7-dihydroxyflavanol, 3′,4′,7-trihydroxyflavanone (butin), 4′,7-dihydroxyflavanone (liquiritigenin), trans-2′,3,4,4′-tetrahydroxychalcone (butein), 4′,5,7-trihydroxyflavanone and trans-2′,4,4′-trihydroxychalcone (isoliquiritigenin). The isolated compounds were used as reference materials for the development of a high-performance liquid chromatography–diode array detector–MS method, which was then applied to analyse (1) fresh silk samples dyed with young fustic, (2) dyed silk subjected to artificially accelerated light ageing and (3) historical silk micro-samples, extracted from ecclesiastical post-Byzantine garments (fifteenth to eighteenth century), which belong to monasteries of Mount Athos. Sulfuretin and fisetin, which are usually used as markers for the identification of the yellow dye and, for the first time, some of the aforementioned flavonoid components of young fustic were identified in the historical extracts. Furthermore, preliminary experiments suggested that although the amounts of the dye components decrease with light ageing, the relative ratio of fisetin and sulfuretin, after a first step of ageing, seems to be almost unaffected by such degradation processes raised by light. The effect of the latter on the morphology of the dyed silk fibres is briefly investigated by scanning electron microscopy.     

Evaluation of chlorophyll fluorescence and membrane injury in the leaves of barley cultivars under osmotic stress

Two physiological tests for screening drought tolerance of barley (Hordeum vulgare, L.) plants are compared in this work. Water deficit is induced by treating the plants' roots with polyethylene glycol (PEG 8000). The relative water content (RWC) of the plants is used as a measure of the water status. Conductometrically determined electrolyte leakage from the leaf tissue demonstrates the membrane injury caused by dehydration. It is shown that the injury index increases with the decrease of the RWC of the leaves. The F(v)/F(m) ratio is employed to assess changes in the primary photochemical reactions of the photosynthetic apparatus after dehydration. The results suggest that PSII is weakly affected by the imposed osmotic stress. The fluorescence behaviour of the examined cultivars is related to their RWC.     

Disruptive technologies in agricultural operations: a systematic review of AI-driven AgriTech research

The evolving field of disruptive technologies has recently gained significant interest in various industries, including agriculture. The fourth industrial revolution has reshaped the context of agricultural technology (AgriTech) with applications of artificial intelligence (AI) and a strong focus on data-driven analytical techniques. Motivated by the advances in AgriTech for agrarian operations, the study presents a state-of-the-art review of the research advances which are, evolving in a fast pace over the last decades (due to the disruptive potential of the technological context). Following a systematic literature approach, we develop a categorisation of the various types of AgriTech, as well as the associated AI-driven techniques which form the continuously shifting definition of AgriTech. The contribution primarily draws on the conceptualisation and awareness about AI-driven AgriTech context relevant to the agricultural operations for smart, efficient, and sustainable farming. The study provides a single normative reference for the definition, context and future directions of the field for further research towards the operational context of AgriTech. Our findings indicate that AgriTech research and the disruptive potential of AI in the agricultural sector are still in infancy in Operations Research. Through the systematic review, we also intend to inform a wide range of agricultural stakeholders (farmers, agripreneurs, scholars and practitioners) and to provide research agenda for a growing field with multiple potentialities for the future of the agricultural operations.