Ni/ZSM‐5 Zeolite Modified Carbon Paste Electrode as an Efficient Electrode for Electrocatalytic Oxidation of Formaldehyde

In this study, we prepared a modified carbon paste electrode consisting of Nickel entrapped in synthesized ZSM‐5 zeolite (Ni/ZMCPE). Then Ni(II) ions were incorporated to electrode by immersion of modified electrode in 1 M Ni(II) ion solution. Cyclic voltammetry and chronoamperometry experiments were used for electrochemical study of this modified electrode; a good redox behavior of Ni(OH)₂/NiOOH couple at the surface of electrode can be observed, the excellent capability of this modified electrode for catalytic oxidation of formaldehyde was demonstrated during the anodic potential sweep in alkaline solution. The amount of transfer coefficient (α), surface coverage (Γ*) of the redox species and catalytic chemical reaction rate constant (k) for formaldehyde were evaluated. Thus, it can be a candidate as an anode for fuel cell application.     

Electrochemical synthesis of a novel platinum nanostructure on a glassy carbon electrode, and its application to the electrooxidation of methanol

We show that the addition of white dextrin during the electrochemical deposition of platinum nanostructures (nano-Pt) on a glassy carbon electrode (GCE) results in an electrochemically active surface that is much larger than that of platinum microparticles prepared by the same procedure but in the absence of dextrin. The nano-Pt deposits are characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy, and electrochemical methods. The SEM images reveal deposits composed of mainly nanoparticles and short nanorods. The GCE was applied as a novel and cost-effective catalyst for methanol oxidation. The use of nano-Pt improves the electrocatalytic activity and the stability of the electrodes.

Mixing Behavior of Cationic Hydrotropes with Anionic Surfactant Sodium Dodecyl Sulfate

Mixing behavior of anionic surfactant sodium dodecyl sulfate (SDS) with cationic hydrotropes aniline hydrochloride (AH), o-toluidine hydrochloride (o-TH), and p-toluidine hydrochloride (p-TH) have been studied using conductivity at different temperatures. Critical micelle concentration for different mixing mole fractions, their ideal values, and different interaction parameters have been estimated. All the parameters show nonideal behavior with synergistic interactions. Thermodynamic parameters are also calculated for these systems.     

Fabrication of Nanocomposite Containing Naphthoquinone and Nanogold Supported on Poly(2,6‐pyridinedicarboxylic acid) Film for Voltammetric Determination of N‐Acetyl‐L‐Cysteine

A modified electrode was fabricated by grafting of poly (2,6‐pyridinedicarboxylic acid) film (PDC) by electropolymerization of 2,6‐pyridinedicarboxylic acid on the glassy carbon electrode (GCE). Then, gold nanoparticles (NG) and 1,2‐naphthoquinone‐4‐sulfonic acid sodium (Nq) were immobilized on the PDC/GCE to prepare Nq/NG/PDC/GCE by immersing electrode into NG and Nq solution, respectively. The Nq species on NG/PDC/GCE could catalyze electrooxidation of N‐acetyl‐L ‐cysteine (NAC) with lowering the over potential by about 600 mV. This method used for detection of NAC in dynamic range from 4.0×10^?6 M to 1.30×10^?4 M with a detection of limit (2σ) 8.0×10^?7 M.     

Preparation of Ni/poly(1,5-diaminonaphthalene)-modified carbon paste electrode; application in electrocatalytic oxidation of formaldehyde for fuel cells

This paper deals with electrochemical oxidation of formaldehyde in alkaline solution with a new electrocatalytic system composed of carbon paste electrode coated with poly(1,5-diaminonaphthalene) (P-1,5-DAN) film containing incorporated Ni(II)/Ni(III) redox ions. The modifier layer of (P-1,5-DAN-Ni)(OH)₂ at the electrode surface acts as a catalyst for the oxidation of formaldehyde in 0.1-M NaOH solution. Cyclic voltammetric and chronoamperometric experiments showed that the formaldehyde can be oxidized at the surface of Ni/P-1,5-DAN-modified carbon paste electrode. In cyclic voltammetry studies, the peak current of the oxidation of nickel hydroxide in the presence of formaldehyde increases and is followed by a decrease in the corresponding cathodic current. The rate constant (k) for the chemical reaction between the formaldehyde and nickel hydroxide has been evaluated by chronoamperometry method. This polymeric-modified electrode can oxidize the formaldehyde with high current density (over 7 mA cm⁻²). Thus, it can be a candidate as an anode for fuel cell applications.     

An electrochemical sensor based on CuO nanoparticle for simultaneous determination of hydrazine and bisphenol A

In the present research, the direct electrochemical oxidation of hydrazine in the presence of bisphenol A was investigated at a copper oxide nanoparticles/ionic liquid/carbon paste electrode (CuO NPs/IL/CPE). The combination of the good conductive 1-hexyl-3-methylimidazolium hexafluorophosphate and CuO nanoparticles resulted in an electrode with attractive properties for the determination of hydrazine in the presence of bisphenol A. The linear dynamic ranges were obtained in the ranges of 0.05–150 and 0.2–175 µM with the detection limits (3sb/m) 0.03 and 0.1 µM for HY and BPA, respectively. High stability, sensitivity, selectivity and reproducibility, fast response, the ease of preparation, and surface renewal made the sensor well suitable for the determination of hydrazine in the presence of bisphenol A, which are important pollutants in the environment. Finally, this new sensor was used for the determination of HY and BPA in some water samples such as river water and wastewater.     

New FRET primers for quantitative real-time PCR

FRET primer real-time PCR chemistry depends on internally labeled primers with FRET dyes linked to their 3′ end. The best distance between the FRET dyes for obtaining the largest signal and the lowest background is six nucleotides. In this study the forward primer was labeled with FAM and the reverse primer with Texas red; the labeled primers meet in cycle two of PCR. At the end of the elongation step FAM is excited to emit fluorescence which will excite Texas red to emit new fluorescence that correlates directly with the quantity of PCR product accumulated. FRET primer techniques amplify short amplicons with unique thermal cycling steps, 0 s at 85 °C for denaturation, 7 s for annealing, and 2 s for elongation. The FRET primer technique was very efficient (92.6, 97.2, and 100%), correlation coefficients were high (1.0, 0.999, and 0.999), and total run time was very short (20, 45, and 40 min per 40 cycles with LightCycler, iCycler, and RotorGene 3000, respectively). When FRET-labeled primers were compared with similar but unlabeled primers it was observed that the FRET primer technique had a lower Ct value and was more efficient than use of unlabeled primers detected by use of SYBR Green I. Figure Schematic diagram of FRET prime real-time PCR Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The cleanness of (symbolic) powers of Stanley-Reisner ideals

Let Δ be a pure simplicial complex on the vertex set [n] = {1,..., n} and I _Δ its Stanley-Reisner ideal in the polynomial ring S = K[x ₁,..., x _n]. We show that Δ is a matroid (complete intersection) if and only if S/I _Δ ^(m) (S/I _Δ ^(m)) is clean for all m ∈ N and this is equivalent to saying that S/I _Δ ^(m) (S/I _Δ ^(m), respectively) is Cohen-Macaulay for all m ∈ N. By this result, we show that there exists a monomial ideal I with (pretty) cleanness property while S/I ^m or S/I ^m is not (pretty) clean for all integer m ≥ 3. If dim(Δ) = 1, we also prove that S/I _Δ ⁽²⁾ Δ (S/I _Δ ²) is clean if and only if S/I _Δ ⁽²⁾ (S/I _Δ ², respectively) is Cohen-Macaulay.