Multicomponent synthesis of C-tethered bispyrazol-5-ols using CeO2 nanoparticles as an efficient and green catalyst

Research on Chemical Intermediates - CeO2 nanoparticles have been used as an efficient catalyst for the preparation of C-tethered bispyrazol-5-ols by pseudo five-component reaction of...     

Vector Optimization w.r.t. Relatively Solid Convex Cones in Real Linear Spaces

Journal of Optimization Theory and Applications - In vector optimization, it is of increasing interest to study problems where the image space (a real linear space) is preordered by a not...     

Zeolite Nanoparticle Modified Carbon Paste Electrode as a Biosensor for Simultaneous Determination of Dopamine and Tryptophan

A new chemically modified electrode is constructed based on an iron(III) doped zeolite modified carbon paste electrode (Fe³⁺Y/ZCME). The electrode was evaluated as a sensor for sub‐micromolar determination of tryptophan (Trp) and dopamine (DA). The measurements were carried out using the differential pulse voltammetry (DPV) method in a phosphate buffer solution with pH = 5. The prepared modified electrode shows voltametric responses with high sensitivity and stability for DA and Trp in optimal conditions. The analytical performance of this sensor has been evaluated for detection of DA and Trp in human serum.     

Reverse mathematics and well-ordering principles: A pilot study

The larger project broached here is to look at the generally sentence “if X is well-ordered then f(X) is well-ordered”, where f is a standard proof-theoretic function from ordinals to ordinals. It has turned out that a statement of this form is often equivalent to the existence of countable coded ω-models for a particular theory T_f whose consistency can be proved by means of a cut elimination theorem in infinitary logic which crucially involves the function f. To illustrate this theme, we prove in this paper that the statement “if X is well-ordered then ε_X is well-ordered” is equivalent to . This was first proved by Marcone and Montalban [Alberto Marcone, Antonio Montalbán, The epsilon function for computability theorists, draft, 2007] using recursion-theoretic and combinatorial methods. The proof given here is principally proof-theoretic, the main techniques being Schütte’s method of proof search (deduction chains) [Kurt Schütte, Proof Theory, Springer-Verlag, Berlin, Heidelberg, 1977] and cut elimination for a (small) fragment of .     

Initiating electropolymerization on graphene sheets in graphite oxide structure

Because of its special chemical composition, graphite oxide has peculiar influences on electrochemical processes. The existence of various functional groups significantly affects electropolymerization processes and the formation of conductive polymers. Electrochemical synthesis of polyaniline (as a prototype of conductive polymers) on a paste‐based substrate of graphite oxide was investigated. In this case, the electropolymerization is significantly different from conventional cases, and the polymer is generated just during the first potential cycle. This can be attributed to the fact that graphite oxide can assist the monomer oxidation. Alternatively, electropolymerization was successfully performed inside the graphite oxide layers via electrochemical treatment of aniline‐intercalated graphite oxide in the supporting electrolyte. Although these phenomena are related to the chemical composition of graphite oxide, the graphite prepared by the reduction of graphite oxide also displayed some advantages for the electropolymerization (over natural graphite). There is an emphasis on the morphological investigations throughout this study, because novel morphologies were observed in the system under investigation. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2204–2213, 2010     

Determination of Total Iron in Environmental Samples by Solid Phase Extraction with Dimethyl(E)‐2‐(2‐Methoxyphenoxy)‐2‐Butenedioate

A novel solid phase extraction technique for determination of total iron in environmental water samples was developed. The method is based on sorption of Fe(III) ions on octadecyl silica membrane disk modified with a new synthetic ligand dimethyl(E)‐2‐(2‐methoxyphenoxy)‐2‐butenedioate (I). Iron(III) is quantitatively retained on the disk in the pH range of 3–7 at a flow rate of 1–7 mL min⁻¹. The Fe(III) eluted with 10 mL of 0.01 M EDTA and than was measured by flame atomic absorption spectrometry (FAAS) at 248.3 nm. The maximum capacity disk modified by 7 mg of ligand was found to be 197 ± 2 μg of iron(III). The breakthrough volume was greater than 2000 mL. The iron(III) was completely recovered (> 99%) from water with a preconcentration factor of more than 200. The limit of detection of the proposed method was 1.00 ng mL⁻¹. The various cationic and anionic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was successfully applied to determination of total iron from three different water samples.     

Herbrand's theorem revisited

We present recent results on the deepening connection between proof theory and formal language theory. To each first-order proof with prenex cuts of complexity at most Π_n/Σ_n, we associate a typed (non-deterministic) tree grammar of order n (equivalently, an order n recursion scheme) that abstracts the computation of Herbrand sets obtained through Gentzen-style cut elimination. Apart from offering a means to compute Herbrand expansions directly from proofs with cuts, these grammars provide a structural counterpart to Herbrand's theorem that opens the door to tackling a number of questions in proof theory such as proof equivalence, proof compression and proof complexity. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Circular proofs for the modal mu-calculus

Inspired by Stirling's tableau proofs [4] we introduce a finite, cut-free sound and complete sequent calculus for the modal mu-calculus. Proofs in this system are finite trees in which leaves are either axioms or assumptions that are discharged by a specific rule of the calculus. The discharge rules provide a way to unfold assumptions motivating the name circular proofs. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)