Fuzzified AHP in the evaluation of scientific monographs

Fuzzification of the analytic hierarchy process (AHP) is of great interest to researchers since it is a frequently used method for coping with complex decision making problems. There have been many attempts to fuzzify the AHP. We focus particularly on the construction of fuzzy pairwise comparison matrices and on obtaining fuzzy weights of objects from them subsequently. We review the fuzzification of the geometric mean method for obtaining fuzzy weights of objects from fuzzy pairwise comparison matrices. We illustrate here the usefulness of the fuzzified AHP on a real-life problem of the evaluation of quality of scientific monographs in university environment. The benefits of the presented evaluation methodology and its suitability for quality assessment of R&D results in general are discussed. When the task of quality assessment in R&D is considered, an important role is played by peer-review evaluation. Evaluations provided by experts in the peer-review process have a high level of subjectivity and can be expected in a linguistic form. New decision-support methods (or adaptations of classic methods) well suited to deal with such inputs, to capture the consistency of experts’ preferences and to restrict the subjectivity to an acceptable level are necessary. A new consistency condition is therefore defined here to be used for expertly defined fuzzy pairwise comparison matrices.     

Addressing lead toxicity: complexation of lead(II) with thiopyrone and hydroxypyridinethione O,S mixed chelators

The lead(II) ion is regarded as a serious environmental contaminant. A considerable need exists to develop selective ligands for remediation of this metal ion. Herein, the coordination chemistry of lead(II) is investigated with three O,S donor ligands: thiomaltol, 3-hydroxy-1-methyl-2(1H)-pyridinethione (3,2-HOPTO), and 3-hydroxy-1,2-dimethyl-4(1H)-pyridinethione (3,4-HOPTO). The X-ray structures of [Pb(thiomaltolato)(2)] and [Pb(3,4-HOPTO)(2)] have been solved, revealing the expected 4-coordinate geometries. Electronic spectra have been obtained for the lead(II) complexes with all three ligands. Preliminary solution studies show that the thiomaltol ligand binds lead(II) preferentially over magnesium(II) and calcium(II); however, [Pb(thiomaltolato)(2)] is not stable in the presence of 1 equiv of EDTA. Tetradentate ligands derived from these O,S chelators are expected to generate higher affinity ligands for lead(II) sequestration.     

Characterization of silsesquioxanes by size-exclusion chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Liquid chromatography in combination with spectroscopic methods like matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) or nuclear magnetic resonance (NMR) spectroscopy is a powerful method to characterize silsesquioxanes and silsesquioxane mixtures. As new examples, the formation of silsesquioxyl-substituted silsesquioxanes [(n-octyl)(7)(SiO(1.5))(8)](2)O and [(n-octyl)(7)(SiO(1.5))(8)O](2)[(n-octyl)(6)(SiO(1.5))(8)] as well as the cage rearrangement of octa-[(n-heptyl)silsesquioxane] to larger structures [(n-heptyl)SiO(1.5))](n) up to n=28 are shown.     

Nanomolar hydrogen peroxide detection using horseradish peroxidase covalently linked to undoped nanocrystalline diamond surfaces

In this article, we report on the low-level detection of hydrogen peroxide, a key player in the redox signaling pathway and a toxic product in the cellular system, using a colorimetric solution assay. Amine-terminated undoped nanocrystalline diamond thin films were grown on glass using a linear-antenna microwave plasma CVD process. The diamond surface consists mainly of -NH(2) termination. The aminated diamond surface was decorated with horseradish peroxidase (HRP) enzyme using carbodiimide coupling chemistry. The success of the HRP immobilization was confirmed by X-ray photoelectron spectroscopy (XPS). The enzymatic activity of immobilized HRP was determined with a colorimetric test based on the HRP-catalyzed oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sufonic acid (ABTS) in the presence of hydrogen peroxide. The surface coverage of active HRP was estimated to be Γ = 7.3 × 10(13) molecules cm(-2). The use of the functionalized diamond surface as an optical sensor for the detection of hydrogen peroxide with a detection limit of 35 nM was demonstrated.     

Determination of chondroitin sulfate content in raw materials and dietary supplements by high-performance liquid chromatography with ultraviolet detection after enzymatic hydrolysis: single-laboratory validation

A method to quantify chondroitin sulfate in raw materials and dietary supplements at a range of about 5 to 100% (w/w) chondroitin sulfate has been developed and validated. The chondroitin sulfate is first selectively hydrolyzed by chondroitinase ACII enzyme to form un-, mono-, di-, and trisulfated unsaturated disaccharides; the resulting disaccharides are then quantified by ion-pairing liquid chromatography with ultraviolet detection. The amounts of the individual disaccharides are summed to yield the total amount of chondroitin sulfate in the material. Single-laboratory validation has been performed to determine the repeatability, accuracy, selectivity, limit of detection, limit of quantification, ruggedness, and linearity of the method. Repeatability precision for total chondroitin sulfate content was between 1.60 and 4.72% relative standard deviation, with HorRat values between 0.79 and 2.25. Chondroitin sulfate recovery from raw material negative control was between 101 and 102%, and recovery from finished product negative control was between 105 and 106%.     

Voltammetric determination of dinitronaphthalenes using a silver solid amalgam paste electrode

The electrochemical behavior and application of a new sensor, a silver solid amalgam paste electrode (AgSA-PE), based on the mixture of a fine silver solid amalgam powder (60:40 (w(Hg)/w(Ag))) and a suitable organic pasting liquid (Paraffin oil) in a ratio of 20:1 (w/w), was investigated in an aqueous-methanolic media (1:1). This alternative working electrode provides simple preparation and handling, adequate mechanical stability, easily renewable electrode surface, sufficiently wide cathodic potential window (up to -1200 mV within a pH range of 2.7-12.3), and sufficient sensitivity without any necessary pretreatment. The practical usability of the AgSA-PE was verified by the development of voltammetric methods for the determination of selected environmentally important pollutants (1,3-, 1,5-, and 1,8-dinitronaphthalenes) in an aqueous-methanolic media (1:1). The differential pulse voltammetric methods at AgSA-PE give linear concentration dependences in the range of 1-100 μmol l(-1) with limits of detection of about 1 μmol l(-1) in a mixture of Britton-Robinson buffer of appropriate pH and methanol (1:1).     

Mechanistic investigations on dimethyl carbonate formation by oxidative carbonylation of methanol over a CuY zeolite: an operando SSITKA/DRIFTS/MS study

The simultaneous combination of steady state isotopic transient kinetic analysis (SSITKA) with diffuse reflectance Fourier transform spectroscopy (DRIFTS) and mass spectrometric (MS) analysis was applied to study the oxidative carbonylation of methanol (MeOH) to dimethyl carbonate (DMC) on a CuY zeolite catalyst prepared by incipient-wetness impregnation of commercial zeolite NH(4)-Y. The interaction of the catalyst with different reactants and reactant mixtures (O(2), CO, CO/O(2), MeOH/O(2), MeOH/CO, and MeOH/CO/O(2)) was studied in detail using (16)O(2)/(18)O(2) as well as (12)CO/(13)CO containing gas mixtures. DMC is produced via a monodentate monomethyl carbonate (MMC) species as intermediate which is formed by the concerted action of adsorbed methoxide and CO with gas phase MeOH. Adsorbed bidentate MMC species were found to be inactive. Lattice oxygen supplied by CuO(x) species is involved in the formation of MMC. Gas phase oxygen is needed to re-oxidize the catalyst but favours also the oxidation of CO to CO(2) and unselective oxidation reactions of MeOH to methyl formate, dimethoxymethane, and CO(2). The appropriate choice of reaction temperature and of the oxygen content in the reactant gas mixture was found to be indispensable for reaching high DMC selectivities.     

Relationships between 31P chemical shift tensors and conformation of nucleic acid backbone: a DFT study

Density functional theory (DFT) has been applied to study the conformational dependence of 31P chemical shift tensors in B-DNA. The gg and gt conformations of backbone phosphate groups representing BI- and BII-DNA have been examined. Calculations have been carried out on static models of dimethyl phosphate (dmp) and dinucleoside-3',5'-monophosphate with bases replaced by hydrogen atoms in vacuo as well as in an explicit solvent. Trends in 31P chemical shift anisotropy (CSA) tensors with respect to the backbone torsion angles alpha, zeta, beta, and epsilon are presented. Although these trends do not change qualitatively upon solvation, quantitative changes result in the reduction of the chemical shift anisotropy. For alpha and zeta in the range from 270 degrees to 330 degrees and from 240 degrees to 300 degrees , respectively, the delta22 and delta33 principal components vary within as much as 30 ppm, showing a marked dependence on backbone conformation. The calculated 31P chemical shift tensor principal axes deviate from the axes of O-P-O bond angles by at most 5 degrees . For solvent models, our results are in a good agreement with experimental estimates of relative gg and gt isotropic chemical shifts. Solvation also brings the theoretical deltaiso of the gg conformation closer to the experimental gg data of barium diethyl phosphate.     

Stereoselective total synthesis of protected sulfamisterin and its analogues

The stereoselective synthesis of sulfamisterin I and its unnatural analogues II and V in their protected form was achieved through a common strategy. The Wittig reaction of aldehydes VIII and IX with the C₁₄ hydrophobic side-chain X served as the key C-C connecting transformation. Subsequent functional group inter-conversions in the coupling products XI and XX completed the total synthesis.     

Speciation analysis of mercury in sediments, zoobenthos and river water samples by high-performance liquid chromatography hyphenated to atomic fluorescence spectrometry following preconcentration by solid phase extraction

A high-pressure microwave digestion was applied for microwave-assisted extraction (MAE) of mercury species from sediments and zoobenthos samples. A mixture containing 3 mol L⁻¹ HCl, 50% aqueous methanol and 0.2 mol L⁻¹ citric acid (for masking co-extracted Fe³⁺) was selected as the most suitable extraction agent. The efficiency of proposed extraction method was better than 95% with R.S.D. below 6%. A preconcentration method utilizing a “homemade” C18 solid phase extraction (SPE) microcolumns was developed to enhance sensitivity of the mercury species determination using on-column complex formation of mercury-2-mercaptophenol complexes. Methanol was chosen for counter-current elution of the retained mercury complexes achieving a preconcentration factor as much as 1000. The preconcentration method was applied for the speciation analysis of mercury in river water samples. The high-performance liquid chromatography-cold vapour atomic fluorescence spectrometric (HPLC/CV-AFS) method was used for the speciation analysis of mercury. The complete separation of four mercury species was achieved by an isocratic elution of aqueous methanol (65%/35%) on a Zorbax SB-C18 column (4.6 mm × 150 mm, 5 μm) using the same complexation reagent (2-mercaptophenol). The limits of detection were 4.3 μg L⁻¹ for methylmercury (MeHg⁺), 1.4 μg L⁻¹ for ethylmercury (EtHg⁺), 0.8 μg L⁻¹ for inorganic mercury (Hg²⁺), 0.8 μg L⁻¹ for phenylmercury (PhHg⁺).