Miracle-dz/UniFAR-FTUs huggingface dataset:
Determination of selenium by hydride generation atomic absorption spectrometry: elimination of interferences from very high concentrations of nickel, cobalt, iron and chromium by complexation

The use of an alkaline sample solution for the determination of Se by the hydride generation technique offers the possibility of eliminating the interference from very high concentrations of Ni2+, Co2+, Fe3+, and Cr3+. In order to achieve this, complexing agents were employed to mask the interfering metal ions. After addition of the masking agent, the pH was adjusted to 12–13 with NaOH, and sodium tetrahydroborate was finally added in order to reduce selenite to selenide ions. The selenium hydride was generated by acidifying the solution with HCl in a flow system. Ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid (DTPA) were found to be effective masking agents for Ni2+ and Co2+; the interference from up to 8000 mg l–1 of Ni2+ or Co2+ was eliminated. Tartrate was found to be a suitable masking agent for Fe3+ and Cr3+ up to 5000 mg l–1. Accurate results were obtained for the National Institute of Standards and Technology Standard Reference Materials 671 Nickel Oxide and 364 Low-alloy Steel, using combinations of DTPA and tartrate as masking agents. The detection limits were 0.1 µg g–1 for the Nickel Oxide and 0.3 µg g–1 for the Low-alloy Steel.
Crystal chemistry and hydrogen bonding of rustumite Ca10(Si2O7)2(SiO4)(OH)2Cl2 with variable OH, Cl, F

Abstract Three samples of the skarn mineral rustumite Ca10(Si2O7)2(SiO4)(OH)2Cl2, space group C2/c, a ≈7.6, b ≈ 18.5, c ≈ 15.5 Å, β ≈ 104°, with variable OH, Cl, F content were investigated by electron microprobe, single-crystal X-ray structure refinements, and Raman spectroscopy. “Rust1_LCl” is a low chlorine rustumite Ca10(Si2O7)2(SiO4)(OH1.88F0.12)(Cl1.28,OH0.72) from skarns associated with the Rize batholith near Ikizedere, Turkey. “Rust2_F” is a F-bearing rustumite Ca10(Si2O7)2(SiO4)(OH1.13F0.87) (Cl1.96OH0.04) from xenoliths in ignimbrites of the Upper Chegem Caldera, Northern Caucasus, Russia. “Rust3_LCl_F” represents a low-Cl, F-bearing rustumite Ca10(Si2O7)2[(SiO4)0.87(H4O4)0.13](OH1.01F0.99) (Cl1.00 OH1.00) from altered merwinite skarns of the Birkhin massif, Baikal Lake area, Eastern Siberia, Russia. Rustumite from Birkhin massif is characterized by a significant hydrogarnet-like or fluorine substitution at the apices of the orthosilicate group, leading to specific atomic displacements. The crystal structures including hydrogen positions have been refined from single-crystal X-ray data to R1 = 0.0205 (Rust1_LCl), R1 = 0.0295 (Rust2_F), and R1 = 0.0243 (Rust3_LCl_F), respectively. Depletion in Cl and replacement by OH is associated with smaller unit-cell dimensions. The substitution of OH by F leads to shorter hydrogen bonds O-H···F instead of O-H···OH. Raman spectra for all samples have been measured and confirm slight strengthening of the hydrogen bonds with uptake of F. This study discusses the complex crystal chemistry of the skarn mineral rustumite and may provide a wider understanding of the chemical reactions related to contact metamorphism of limestones
Binuclear phthalocyanines covalently linked through two- and four-atom bridges

Binuclear phthalocyanines in which the two phthalocyanine nuclei are covalently linked through four-atom bridges, derived from catechol, have been prepared and characterized. Metal-free 2,9,16,23-tetra-(3,3-dimethylbutyl)phthalocyanine and 2,9,16,23-tetra-(2-trimethylsilylethyl)phthalocyanine were prepared as examples of non-oxygenated mononuclear phthalocyanines soluble in organic solvents. Catalytic hydrogenation of 1,2-bis-(3,4-dicyanophenyl)ethyne and 1,4-bis-(3,4-dicyanophenyl)buta-1,3-diyne gave 1,2-bis-(3,4-dicyanophenyl)ethane and 1,4-bis-(3,4-dicyanophenyl)butane respectively. From these precursors, metal-free phthalocyanine dimers containing ethylene and tetramethylene bridges, joining the phthalocyanine nuclei, were prepared. Two of the two-atom bridge phthalocyanine dimers represent the first characterized phthalocyanine dimers not containing alkoxy or oxygenated groups.
Electronic structures and ferromagnetism of Cu- and Mn-doped ZnO

The electronic structures of magnetic orderings of Zn1? xTMxO (TM = Cu, Mn) have been studied with the B3LYP hybrid density functional. The corrections for energy band dispersions with respect to the local density approximation (LDA) are similar to GW results, but lead to an improved energy gap. Cu and Mn are close to +2 valence in Zn1? xTMxO (TM = Cu, Mn), but Cu1+ would be realized in n-type ZnO. Cu-? and Mn-doped ZnO have ferromagnetic and antiferromagnetic ground states, respectively. Magnetic couplings between transition metal ions depend sensitively on the interatomic distance.
Nanostructured electrocatalysts immobilised on electrode surfaces and organic film templates

The development of new electrocatalysts with the aim of enhancing the rate of electrochemical reactions has been a long-term goal of electrochemists. In part, this is due to the great importance of electrocatalysts in energy generation and environmental concerns. In this review, various methods of the preparation of nanostructured electrocatalysts and their applications after attachment to the electrode surface are described. Diazonium chemistry has been extensively used for the preparation and attachment of nanostructured electrocatalysts and this review thus describes the recent developments and applications of this chemistry in electrocatalysis. The preparation of nanostructured electrocatalysts including grafted molecular films and metal nanoparticles physically adsorbed on electrode surfaces and those attached to the surface by molecular links using diazonium chemistry is reviewed. Two methods for the attachment of nanoparticles by simple physical adsorption and by electrochemical deposition on molecular films are described and the electrochemical response of nanostructured electrocatalysts for some of the most common electrochemical reactions is discussed.
Porous Biodegradable Polyesters, 3. Preparation of Porous Poly(ɛ-caprolactone) Films from Blends by Selective Enzymatic Removal of Poly(L-lactide)

Porous poly(e-caprolactone) (PCL) films were prepared by the removal of poly(L-lactide) (PLLA) from phase-separated PLLA/PCL blend films using the selective Proteinase K-catalyzed hydrolysis of PLLA and subsequent elution of its water-soluble oligomers and monomer into the surrounding hydrolysis media. Polarimetry, gravimetry, and differential scanning calorimetry (DSC) confirmed the complete removal of PLLA molecules from the blend films within 5 d of the Proteinase K catalyzed hydrolysis and therefore the formation of porous PCL films when the initial PLLA content [X PLLA(0) (w/w) = PLLA/(PCL + PLLA)] of the blend films was in the range 0.3-0.5. The fragmentation of the blend film with X PLLA(0) 0.7 occurred when the Proteinase K-catalyzed hydrolysis was continued for longer than 5d. These findings exhibited that both the PLLA-rich and PCL-rich phases were continuous in the blend films for X PLLA(0) ranges of 0.3-0.7 and of 0.3-0.5, respectively, and that the PCL rich phase became dispersed when X PLLA(0) was increased to 0,7. The dependence of enzymatic hydrolysis rate on X PLLA(0) strongly suggests that the Proteinase K-catalyzed hydrolysis of the blend films oceurs at the interfaces of PLLA-rich and PCL-rich phases as well as at the film sur faces.
Facile fabrication of large area nanostructures for efficient surface-enhanced Raman scattering{

Large area SERS (surface-enhanced Raman scattering)-active films with closely packed nanoembossed Ag arrays were reproducibly fabricated by the replication method of polymer surfaces with nano-size grooved Al masters. Three different sizes (60, 105 and 420 nm) of nanoembossed polymer surface were produced from three different replication masters obtained by controlled anodization conditions of Al, which could be further coated with silver in various thicknesses by an ion sputtering technique. Nanoembossed Ag films with an emboss size of 420 nm, uniformly formed over all the areas of 1 × 1 cm2, exhibit very even SERS activity and the enhancement factor estimated using benzenethiol as a prototype adsorbate reaches as large as 6.6 × 105. Many replicas of polyethylene and polystyrene could be produced from one replication master by this simple replication method with high reproducibility. Almost the same SERS intensities were observed in ten different spots of each replica and twenty different replicas from one replication master.
Electronic States, Absorption Spectrum and Circular Dichroism Spectrum of the Photosynthetic Bacterial LH2 Antenna of Rhodopseudomonas acidophila as Predicted by Exciton Theory and Semiempirical Calculations

A new approach that uses a combination of semiempirical configuration interaction method and exciton theory to calculate electronic energies, eigenstates, absorption spectrum and circular dichroism (CD) spectrum of the LH2 antenna of Rhodopseudomonas acidophila is introduced. A statistical simulation that uses experimental homogeneous line widths was used to account for the inhomogeneous line width of the observed spectrum. Including the effect of orbital overlap of the close-lying pigments of the B850 ring and the effect of the pigment protein interaction in the B800 ring allowed a successful simulation of the experimental absorption and CD spectra of the antenna at room temperature. Two experimental parameters, the transition energy and the magnitude of the transition dipole moment of monomeric bacteriochlorophyll a (Bchl a), were used in the calculation. The dielectric constant of the protein matrix was taken as 2.1 [e0]. The questions of localization lengths of the excitonic states and the energy tran.
Chlorinated pesticides levels in human adipose tissue in the district of Poznań

Abstract Samples of adipose tissue from the abdominal cavity were taken at random at surgeries on abdominal cavity /24 samples/ and at necropsy of the deceased /29 samples/ in the early nineteen eighties. The samples were then analyzed for the presence of chlorinated pesticides by means of gas chromatography with electron capture detection. All the analyzed samples contained beta‐BHC, Lindane, HCB, pp'‐DDE and DDT isomers.
Determination of the Real Influence of the Addition of Four Thickening Agents in Creams Using Rheological Measurements

This study aimed to characterize different emulsions obtained by the addition of four thickening agents, using rheological measurements, beyond analyzing the emulsions by polarized light microscopy looking for liquid crystals on them. The addition of these four thickening agents did not modify the base emulsion rheology, only an improvement in the sensory of the formulation was verified. The polarized light microscopy showed the formation of liquid crystalline structures in all the formulations, thus, the thickening agents did not influence in this parameter too. However, the emulsions could be considered appropriated for cosmetic purposes, probably being highly physically stable.
Synthesis of arylacetylenes by the sodium hydride catalyzed cleavage of 4-aryl-2-methyl-3-butyn-2-ols

Arylbromide (I) reagieren mit dem AcetyIen-Aceton-Addukt (II) in Gegenwart eines Pd-Katalysators zu den Substitutionsprodukten (III), die mit NaH in z.Tl. guten Ausbeuten zu den Arylacetylenen (IV) gespalten werden.
Facile synthesis of hybrid nanostructures from nanoparticles, nanorods and nanowires

We show the anisotropic selective growth of gold particles onto various nanomaterials to form heterodimers, tadpole-like and necklace-like hybrid structures via simple nucleation. The morphology of these hybrid nanostructures can be easily controlled. Necklace-like Pt–Au nanostructures demonstrated high stabilities as electrocatalysts for oxygen-reduction reaction.
Fabrication and Optimization of Porous Silicon Substrates for Diffusion Membrane Applications

The application of porous silicon (PS) as a filter substrate in microstructured systems is a promising field of research. Based on this approach, metal-assisted chemical etching is applied to produce PS in a cheap and fast way. This simple and effective method enables the fabrication of PS with different morphologies, pore distribution, and thickness by varying the deposited metal type and thickness, and the Si doping type and level. The metal (Au, Pt) is sputtered in varied thicknesses on patterned p- or n-doped silicon wafers. The etching solution consists of an 1:1:1 mixture of HF:H 2 O 2 :EtOH. Etching time and temperature are varied showing a direct effect on the pore depth. To obtain a thin permeable porous Si layer, advanced silicon etching is used to microstructure the back side of the patterned wafer. Hence, the resulting PS layers turn to thin membranes ∼150 μm thick, maintaining the desired mechanical stability at enhanced gas-permeation rates and thus face a very auspicious career as gas diffusion substrates.
Optical Properties of Annealed Tin(II) Oxide in Different Ambients

Tin (II) oxide powder is coated at room temperature onto transparent glass substrates by direct thermal evaporation. The films have high transparency (more than 80%) in the visible and near-infrared regions of the electromagnetic spectrum. In the region between 300 and 1300 nm interference fringes are sharp and well defined. The interference fringes are used to calculate the thickness of the amorphous as-prepared film (≈ 722 nm) and the refractive index is found to be 1.84 at 700 nm. The absorption coefficient of this film ≈ 6 × 10−3 cm−1 at 355 nm. The thickness of the film thus measured was compared with results obtained from the Tolansky method. The optical band gap calculated from the simple power law was found to be 3.3 eV. The films are annealed in either O2 or N2 atmosphere for 1 h at various temperatures between 250 and 400 °C. It is found that the film is quite stable until about 400 °C, beyond which the optical band gap reduces to 2.7 eV (in N2 atmosphere) and increases to 3.4 eV (in O2 atmosphere). At higher temperature the films annealed in nitrogen ambient do not show the interference fringes, whereas in the oxygen atmosphere the interference fringes are still observed.
Antioxidant Activities of Acidic Ethanol Extract and the Anthocyanin Rich Fraction from Aronia melanocarpa

The objective of this study was to investigate the antioxidant activities and anthocyanin profiles in the anthocyanin rich fraction (ARFAM) of Aronia melanocarpa, which are considered functional substances and are available as food coloring agents in Korea. Anthocyanins were identified by reversed-phase C18 column chromatography and HPLC-DAD-ESI/MS analysis. The antioxidative activity of the acidic ethanol extract (AME) and the anthocyanin-rich fraction (ARFAM) was determined by scavenging of the diphenylpicrylhydrazyl (DPPH) radical, the hydroxy radical, and the superoxide anion in addition to reducing power using a commercial antioxidant as a reference.
Factor Analysis Scale of Generalized Amino Acid Information as the Source of a New Set of Descriptors for Elucidating the Structure and Activity Relationships of Cationic Antimicrobial Peptides

Factor Analysis Scale of Generalized Amino Acid Information (FASGAI), as a new set of amino acid descriptors, reflecting hydrophobicity, alpha and turn propensities, bulky properties, compositional characteristics, local flexibility, and electronic properties, was derived from multi-dimensional properties of 20 coded amino acids. Quantitative Structure–Activity Relationship (QSAR) analyses on 101 cationic Antimicrobial Peptides (AMPs) with 15 residues were then performed using FASGAI representation, Genetic Algorithm (GA) selection features, and Partial Least Squares (PLS) modeling. It was found that electronic properties of the tenth residue, bulky properties of the seventh residue, hydrophobicity of the twelfth residue, electronic properties of the third residue were highly positively correlated to antibacterial activity, whereas, hydrophobicity of the sixth residue, compositional characteristics of the sixth residue, and hydrophobicity of the tenth residue were highly negatively correlated to antibacterial activity. Analysis of variance demonstrated that a specific sequence rather than an overall sequence of AMPs may be responsible for high activity. Favorable results showed that FASGAI descriptors cherish many distinguished advantages such as plentiful structural information, easy manipulation, straightforward physicochemical meaning, and high characterization competence, and GA for parameter selection is valid in QSAR of antimicrobial peptides studied. These have thus pointed us further into the potential direction of investigation on structures and functions of other various functional peptides.
[60]Fullerene and three [60]fullerene derivatives in membrane model environments

Aggregation of C60 and of three C60 derivatives in phosphatidylcholine liposome model membranes was studied via photophysical investigations. The triplet properties of these fullerenes, including the absorption spectrum between 400 and 900 nm, molar absorption coefficient, quantum yield of formation and/or quantum yield for the photosensitised production of 1O2 were determined in benzene solution and in liposomes. One of the derivatives was a cyclopropyl-fused hexa-addended C60 containing as addend C(CO2C18H37)2 (1). The other two derivatives were cyclohexyl-fused C60 with leucine (2) or hydrophilic acidic (3) mono-addend functionalisation. The synthesis of derivative 2, by thermal extrusion of sulfur dioxide from the corresponding sulfone in the presence of C60, is described. [60]Fullerene and derivative 1 show no T–T absorption in liposomes, although they do so in benzene solution (with a low triplet quantum yield for hexa-addended 1). The absence of triplet–triplet absorption in liposomes is indicative of fullerene aggregation. By contrast, the amphiphilic mono-addend derivatives 2 and 3 present appreciable T–T absorption in liposomes, although less marked than in benzene solution. Mono-addend functionalisation therefore appears to be an interesting way to prevent or diminish fullerene aggregation. Moreover, in this type of derivatisation most of the photophysical properties of pristine [60]fullerene are retained.
Critical micelle concentration determination in binary mixtures of ionic surfactants by deconvolution of conductivity/concentration curves

Une nouvelle methode de determination de la concentration critique micellaire (CMC) d'agents de surface ioniques en solution aqueuse, a partir des mesures de la conductivite electrique est developpee. Cette methode est appliquee a differents systemes eau/agents de surfaces cationiques (DETAB=decyltrimethylammonium bromure, DTAB=dodecyltrimethylammonium bromure, TTAB=tetradecyltrimethylammonium bromure et CTAB=cetyltrimethylammonium bromure)
Pt-free transparent counter electrodes for dye-sensitized solar cells prepared from carbon nanotube micro-balls

Since their initial invention, dye-sensitized solar cells (DSSCs) have offered cost-effective photovoltaic systems. For their counter electrodes, DSSCs generally employ Pt nanoparticles. However, Pt is expensive, rare, and already widely in demand as catalyst in various chemical and electrochemical fields. Substitutes for Pt have been sought among carbon materials, such as activated carbon, carbon black, and carbon nanotubes. Carbon nanotubes (CNTs) are the most appealing candidates, because of their favorable electrochemical catalytic activities. Unfortunately, as with other carbon materials, CNTs cannot provide high charge exchange currents. To obtain performances comparable to Pt counter electrodes, large surface areas are required, resulting in thick electrodes. We have found that transparent Pt-free counter electrodes suitable for DSSCs can be prepared using MWCNT micro-balls deposited on transparent substrates. The deposition density (i.e., the number of CNT micro-balls per unit area) can be controlled, allowing transparency and DSSC performance to be tuned. For a counter electrode transparency of 70%, the efficiency of a DSSC using CNT micro-balls is more than 80% of one using Pt nanoparticles. The prepared CNT micro-balls can be usefully applied in other electrochemical devices, such as battery and supercapacitors.
Hydrogenation and Redox Isomerization of Allylic Alcohols Catalyzed by a New Water-Soluble Pd–tetrahydrosalen Complex

For applications in aqueous media, sulfonated tetrahydrosalen (sulfosalan, HSS) was synthesized by sulfonation of tetrahydrosalen in fuming sulfuric acid. The Pd(II) complex of this ligand, [Pd(HSS)], showed outstanding activity in hydrogenation and redox isomerization of allylic alcohols in homogeneous aqueous solutions or in aqueous–organic biphasic systems (for oct-1-en-3-ol TOF(hydrogenation) = 1580 h–1, TOF(redox isomerization) = 400 h–1). DFT calculations revealed that H2 is activated heterolytically, resulting in a Pd(II)–hydride complex, [Pd(H)(HSS-Hphen)], in which one of the phenolate oxygens is protonated. Both hydrogenation and redox isomerization take place via concerted transfer of a proton and a hydride from the hydrogenated catalyst to the allylic alcohol.
Synthesis and near-infrared luminescence of 3d-4f bi-metallic Schiff base complexes

The reaction of the zinc(II) Schiff base complex ZnL [H2L=N,N′-bis(3-methoxysalicylidene)ethylene-1,2-diamine] with one equivalent of Ln(NO3)3·xH2O (Ln=Nd, Ho, Er or Yb) gives the neutral 3d-4f bi-metallic Schiff base complexes [Zn(NO3)(μ-L)Ln(NO3)2(H2O)], which in solution exhibit emission corresponding to the Ln(III) ions (Ln=Nd, Er and Yb) in the near-infrared region.
Development of a chemiluminescent enzyme immunoassay for the determination of dexamethasone in milk

An indirect competitive chemiluminescent enzyme-linked immunosorbent assay (CL-ELISA) for the determination of dexamethasone (DEX) was developed using soybean peroxidase (SbP) as an enzyme label. A mixture of 3-(10′-phenothiazinyl)-propane-1-sulfonate (SPTZ) and 4-morpholinopyridine (MORPH) was used as an enhancer of SbP-induced chemiluminescence. Varying the concentrations of the capture antigen (DEX-ovalbumin) and specific anti-DEX antibody, the conditions of the assay were optimized. The values of IC10, IC50 and working range (IC20–IC80) of the CL-ELISA of DEX were 0.02, 0.9, 0.08–9.3 ng mL−1, respectively. It was shown that a pretreatment of cow milk samples by centrifugation and 25% methanol prevented the matrix effect of whole milk. The coefficient of variation (CV) and recovery values from the spiked milk samples estimated by the developed CL-ELISA were in the range of 2.2 to 9.9% and 82 to 142%, respectively.