Miracle-dz/UniFAR-FTUs huggingface dataset:
MECHANISM OF THE NITROSATION OF THIOLS AND AMINES BY OXYGENATED NO SOLUTIONS : THE NATURE OF THE NITROSATING INTERMEDIATES

The nitrosation of various thiols and morpholine by oxygenated •NO solutions at physiological pH was investigated. The formation rates and the yields of the nitroso compounds were determined using the stopped-flow technique. The stoichiometry of this process has been determined, and is given by 4•NO + O2 + 2RSH/2RR‘NH → 2RSNO/2RR’NNO + 2NO2- + 2H+. Kinetic studies show that the rate law is −d[O2]/dt = k1[•NO]2[O2] with k1 = (2.54 ± 0.26) × 106 M-2 s-1 and −d[•NO]/dt = 4k1[•NO]2[O2] with 4k1 = (1.17 ± 0.12) × 107 M-2 s-1, independent of the kind of substrate present. The kinetic results are identical to those obtained for the autoxidation of •NO, indicating that the rate of the autoxidation of •NO is unaffected by the presence of thiols and amines. The nitrosation by •NO takes place only in the presence of oxygen, and therefore the rate of the formation of S-nitrosothiols from thiols and oxygenated •NO solution is relatively slow in biological systems. Under physiological conditions where [•NO] < 1 μM and .
Changes in the Hydration States of Poly(N-alkylacrylamide)s during Their Phase Transitions in Water Observed by FTIR Spectroscopy†

Phase transitions of poly(N-n-propylacrylamide) (PnPA), poly(N-isopropylacrylamide) (PiPA), and poly(N-cyclopropylacrylamide) (PcPA) in H2O and D2O were investigated by Fourier transform infrared (FTIR) spectroscopy. IR spectra of these solutions were measured as a function of temperature (T) both in the heating and cooling processes. Subtraction of a spectrum at starting temperature (T0) from a spectrum at T gives an IR difference spectrum (ΔAT-T0). The magnitudes of ΔAT-T0 for IR absorption bands attributable to the alkyl and amide groups of these polymers critically increased at their lower critical solution temperatures (LCSTs). Redshifts of the amide II, C−H stretching, and C−H deformation bands were observed during the coil-to-globule transitions of these polymers. The amide I‘ bands of N-deuterated amide groups (−COND−) in PnPA and PiPA measured below their LCSTs could be fitted with single Gaussian components centered at 1630 and 1625 cm-1, respectively. In contrast, two components were observed i.
Kinetics of the unrolling of small unilamellar phospholipid vesicles onto self-assembled monolayers

Self-assembled monolayers (SAMs) comprised of a mixture of a cholesterol functionalized thiol derivative and a short chain ethyleneoxythiol derivative have been used to attach phospholipid bilayers to gold surfaces. The cholesterol derivatives serve as “anchoring units” and are inserted into the lower leaflet of the attached bilayer. The short chain ethyleneoxy derivatives are present to promote a disordered hydrophilic region beneath the bilayer. The bilayers were formed by incubation of the SAMs with small unilamellar vesicles. On single component hydrophobic surfaces a single lipid layer was adsorbed, while on mixed SAMs containing the cholesterol anchoring units, and single component hydrophilic surfaces, a lipid bilayer was adsorbed. The kinetics of bilayer formation was followed using surface plasmon resonance spectroscopy, and showed dramatic differences depending on the SAM composition.
Achieving maximum photo-oxidation reactivity of Cs(0.68)Ti(1.83)O(4-x)N(x) photocatalysts through valence band fine-tuning

Does a wider absorption range of the photocatalyst always result in a higher photoreactivity? By investigating a set of Cs0.68Ti1. 83O4−xNx (x = 0–0.31) photocatalysts with a continuously tuned absorption edge, we found that although the absorption edge of Cs0.68Ti1. 83O4−xNx is gradually shifted to the low-energy region with the increase of the nitrogen dopant, the photoreactivity of the photocatalyst in terms of generating the ˙OH radical does not correspondingly increase under the irradiation of monochromatic light of 254 nm and continuous spectrum of >300 nm. The fundamental mechanism of the anion dopant enhanced photocatalytic activity through the interplay of three key factors—absorbance, oxidative potential and mobility of charge carriers—is proposed to explain the observed photocatalytic activity change.
Catalytic Activity−d-Band Center Correlation for the O2 Reduction Reaction on Platinum in Alkaline Solutions

We determined, by the rotating disk electrode technique, the kinetics of the oxygen-reduction reaction (ORR) on the surfaces of single crystals of Au(111), Ag(111), Pd(111), Rh(111), Ir(111), and Ru(0001), on Pt monolayers deposited on their surfaces, and also on nanoparticles of these metals dispersed on high-surface-area carbon. Plotting the correlation between the experimentally determined activities of these three types of electrocatalysts with the calculated metal d-band center energies, ed, revealed a volcano-type dependence. In all cases, the electronic properties of the metal electrocatalysts, represented by the ed value, were used for elucidating the metal-dependent catalytic activities, and establishing their electronic propertiesthe ORR kinetics relationship. Pt(111), Pt/C, and Pt/Pd(111) were found to top their corresponding volcano plots. Pd in alkaline solutions showed particularly high activity, suggesting it may offer potential replacement for Pt in fuel cells.
Removal of arsenic(III) from aqueous solution by activated carbons prepared from solvent extracted olive pulp and olive stones

The removal of As(III) from aquatic solutions at different concentrations and pH by using four types of activated carbons obtained from solvent extracted olive pulp and olive stone waste materials was studied. The adsorbents are obtained by chemical (K2CO3 and HNO3) activation and physical (water vapor) activation. The results show that carbons produced by chemical and physical activation of solvent extracted olive pulp and olive stones are efficient adsorbents for arsenic removal. Arsenic adsorption follows a Langmuir isotherm. The best results were obtained with the adsorbent, obtained from extracted olive pulp by pyrolysis in the presence of water vapor. The maximum removal was found to be 18.60 μmol/g. The adsorption capacity for adsorbents, obtained from extracted olive pulp and olive stones, is 11.42 and 9.85 μmol/g, respectively. The test showed that alkaline aqueous medium favored the removal of As(III). Some experiments were carried out to study the oxidation of arsenite to arsenate in the presen.
Tables of the Dynamic and Kinematic Viscosity of Aqueous KCl Solutions in the Temperature Range 25-150 C and the Pressure Range 0.1-35 MPa,

Tabulated values of the dynamic and kinematic viscosity of aqueous sodium chloride solutions are given. The tables cover the temperature range 20–150 °C, the pressure range 0.1–35 MPa and is the concentration range 0–6 molal. It is estimated that the accuracy of the tabulated values is ±0.5%. The correlating equations from which the tables were generated are given.
Investigation of the behavior of the Ni catalyst in chemical vapor deposition synthesis of carbon nanopearls

The role of the nickel catalyst size and its chemical and structural evolution during the early stages of carbon nanopearl nucleation and growth, by chemical vapor deposition from acetylene/argon mixture, was investigated and correlated with the resulting nanopearls morphological and structural properties. Carbon nanopearls were grown using Ni nanoparticles that were 20 nm and 100 nm in size, at a growth temperature of 850 °C, for the following growth times: 10sec, 30 sec, 60 sec, 90 sec, 120 sec and 300 sec. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy were performed on the carbon nanopearl samples. The X-ray diffraction and X-ray photoelectron spectra showed the following chemical constituents were present during the growth of carbon nanopearls: NiO, Ni2O3, Ni3C, Ni, CO and C (both amorphous and graphite). Transmission electron microscopy showed an increase in carbon nanopearl size with larger Ni nanoparticles. Finally, the results showed that the 20 nm Ni nanoparticles chemically reacted sooner than the 100 nm Ni nanoparticles.
Dissociation reaction of N8 azapentalene to 4N2: A theoretical study

We present a theoretical study on the dissociation reaction of N8 azapantalene to four N2 molecules. The process proceeds via isomerization of N8 azapentalene to N8 azidopentazole, which then dissociates directly into four nitrogen molecules. The calculations have determined the relative energies of the two isomers and the two transition states involved in the dissociation process. The results show azidopentazole to be 13 kcal/mol more stable than azapentalene. The barrier to dissociation into four N2 molecules is computed to be 19 kcal/mol. It is concluded that N8 is not stable enough to be considered as a candidate for a high-energy density material. The calculations have been carried out using multiconfigurational self-consistent field and second-order perturbation theory. c 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 311-315, 2000
Survey and Distribution of Plant Parasitic Nematodes Inhabiting Farmlands around Kware Lake

A survey was conducted on nematodes associated with soils of farmlands around Kware Lake, Kware local government area of Sokoto State. The aim this research is to determine the species composition and distribution of nematodes in farmlands around Kware Lake. Sampling was carried out from July to September, 2016. Soil samples were collected to a depth of 0-15 m. Centrifugation technique was used for the extraction of nematodes and viewed under the microscope. Results indicates that seven species were detected whose richness varied with respect to sites. The nematodes detected were Xiphinema spp. , Heterodera spp. , Trichodorus spp. , Meloidogyne spp. , Rotylenchus spp. , Longidorus spp. and Pratylenchus spp. The most abundant nematodes isolated were Meloidogyne spp. (29.63%) while Pratylenchus spp. were found to be least abundant (2.22%). This is because Meloidogyne was very widely distributed and affect a wide variety of crops while Short Research Article Magami et al.; AJRIB, 2(4): 1-8, 2019; Article no.AJRIB. 53337 2 Pratylenchus was a migratory endoparasite and can be ascertain by its high population in the root. There was no significant difference on nematode species occurrence between the three sampling sites at p<0.05. The result showed there was wide diversity of nematodes inhabiting the study area with diversity index of 1.77. The presence of plant parasitic nematodes in the soils of farmlands around Kware Lake highlights need for prevention and control of nematode species, so as to reduce the risk of losses to agricultural yield.
Structural analysis of magnetic nanocrystals embedded in silicate glasses by anomalous small‐angle X‐ray scattering

The present work reports the structural analysis of magnetic nanocrystals of Fe- and Mn-containing phases formed during annealing of the glass 13.6Na2O–62.9SiO2–8.5MnO–15.0Fe2O3−x (mol%) at 823 K for different periods of time. X-ray diffraction investigation shows the formation of a mixture of MnFe2O4 and Fe3O4 phases. Furthermore, small-angle X-ray scattering and anomalous small-angle X-ray scattering (ASAXS) experiments were used to extract quantitative information about the structure of the formed nano-sized crystals, as well as their phase compositions, volume fractions and size distributions. ASAXS analysis reveals the formation of spherical core–shell particles with the size of the particles between 10 and 50 nm. The concentrations of iron atoms in the core are higher than those in the shell and in the remaining matrix. With increasing annealing time, the ratio of Mn to Fe increases in the nanoparticles and the crystalline phase moves toward the pure jacobsite phase. Evaluated compositions reveal the presence of SiO2 in the shell. This shell acts as a diffusion barrier for the nanocrystal-forming ions, and the growth of the particles is kinetically constrained.
Study of Polymer Electrolyte Membrane Degradation under OCV Hold Using Bilayer MEAs

Accelerated degradation tests for polymer electrolyte membrane fuel cells are frequently conducted under open-circuit voltage (OCV) conditions at low relative humidity and high temperature. Comparative experimental studies were carried out to identify the localization of membrane degradation through the thickness direction of the membrane under the OCV hold condition and the effect of platinum band location on the membrane degradation behavior. A bilayer configuration of the membrane electrode assemblies (MEAs) was used for this study. In one test, the fuel cell with the bilayer MEA was exposed to hydrogen and air (regular test); in another test, the bilayer MEA was exposed to 4% hydrogen (balance nitrogen) and pure oxygen to induce the platinum band formation close to the anode side. Hydrogen crossover current, electrochemical areas (ECAs), and polarization curves were evaluated pre- and post-test. After the OCV hold test, the bilayer MEA was separated into two pieces of one-side coated membranes; each piece was characterized by uniaxial mechanical testing, IR spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (EDS) analysis. The findings suggest highly localized degradation or a defect band formed through the thickness direction of the MEA, and the defect band shifts with the shift of the Pt band.
A novel microsensor for determination of apparent diffusivity in sediments

A microsensor for determination of apparent gas diffusivity in pore waters and biofilms is described. The measurement is based on diffusion from an internal gas reservoir, through an internal diffusion barrier positioned within the sensor tip and out into the surrounding medium. The concentration of the gas at the tip of the sensor is then a function of the apparent diffusivity in the medium. Hydrogen was used as a tracer gas in our test 140‐µm thick sensor, but other less reactive gasses may also be used. A mathematical model, describing the signal as a function of diffusivity, is presented; it is shown that a calibration curve can be constructed from measurements in only two media with known diffusivity, such as stagnant water and a sediment composed of microscopic glass beads. The sensor‐determined apparent diffusivities in a variety of media agree well with parallel determinations using a diffusion chamber. The signal from our 140‐µm sensor depends on the diffusivity in a spherical volume within a radius of 0.5 mm from the tip. By use of the diffusivity sensor, it is possible to obtain a much higher spatial resolution of diffusivity in sediments and biofilms than by any other nonoptical method.
Edge-Flames and Their Stability

Flame sheets that arise in non-premixed combustion often have edges. The leading edge of a flame spreading over a fuel-bed, solid or liquid, is one example. The edge of a hemi-spherical candle flame in microgravity is another. We construct a one-dimensional model which contains some of the essential physics of these edge-flames, and use this model to describe stationary solutions and their stability. The model corresponds to a new class of combustion waves which resemble deflagrations in some respects yet exhibit important differences. Thus, in a uniform flow, wave-like solutions are possible with positive, negative or vanishing wave-speeds, depending on an assignable Damkohler number. At large activation energy, reaction is concentrated primarily in a thin region (the edge) but it persists, in diminished form, behind the edge. This residual reaction plays a key role in defining the flame - or edge-temperature which, in turn, controls the dynamics of the structure. The familiar Lewis-number stability boun.
Shape and SPR Evolution of Thorny Gold Nanoparticles Promoted by Silver Ions

The gold-seed-mediated growth approach is developed to obtain three-dimensional (3D) thorny gold nanoparticles, and their morphology can be tailored by introducing different amounts of Ag+ ions into the reaction systems of HAuCl4 and NH2OH in the absence of templates and surfactants. Changing the concentration of silver ions from 0 to 2.5 × 10-6 M leads to the gradual deviations of the resulted nanoparticle morphology from the spherical geometry. The morphology of gold nanoparticles can be tuned from sphere to the anomalous nonspheres, to the gold nanoparticles with short thorns, to the gold nanoparticles with long thorns of more than 100 nm. At too high concentrations (above 2.5 × 10-6 M), the number of the nanothorns on each gold nanoparticle decreased and the central parts of the 3D gold nanostructures (the body) expanded. For the gold nanoparticles with short thorns, most of the short thorns are single crystals and the rest are 2- or 5-fold twinned crystals. However, the long gold thorns consist mainl.
Is the Hartree-Fock prediction that the chemical potential µ of non-relativistic neutral atoms is equal to minus the ionisation potential I sensitive to electron correlation?

Numerical estimates of the chemical (µ) and ionisation (I) potentials from natural orbital functional (NOF) theory of one of us are presented for neutral atoms ranging from H to Kr, and compared with the corresponding experimental ionisation energies. The semi-empirical treatment by Vela et al. relates µ approximately to the measured I. By a physical argument based on the concept of the Pauli potential, we thereby derive in the fully correlated ground states of atoms. The predicted vertical I by means of the extended Koopmans' theorem is in good agreement with the corresponding experimental data. However, the NOF theory of µ lowers the experimental values considerably though oscillatory behaviour is again in evidence. This comparison has prompted us to reopen the Hartree-Fock prediction by Alonso and March that .
Finite size effects in ZnO nanoparticles: An electron paramagnetic resonance (EPR) analysis

ZnO nanoparticles were synthesized by solid coprecipitation method with consecutive high energy ball milling procedure. By reducing the particle size of ZnO to nano dimensions strong nano‐size effects were observed. In order to characterize the ZnO defect structure, EPR has been applied. It was observed that below 50 nm the surface defects play a dominant role in the electronic properties of ZnO. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Longitudinal and bulk viscosities of expanded rubidium

First three non-vanishing sum rules for the bulk and longitudinal stress auto-correlation functions have been evaluated for liquid Rb at six thermodynamic states along the liquid–vapour coexistence curve. The Mori memory function formalism and the frequency sum rules have been used to calculate bulk and longitudinal viscosities. The results thus obtained for the ratio of bulk viscosity to shear viscosity have been compared with experimental and other theoretical predictions wherever available. The values of the bulk viscosity have been found to be more than the corresponding values of the shear viscosity for all six thermodynamic states investigated here.
Temperature dependence of electron attachment and detachment in SF6 and c‐C4F6

In the temperature, T, range of 300–600 K and the mean electron energy range 〈e〉 of 0.19–1.0 eV, the total electron attachment rate constant for SF6 and c‐C4F6 measured in dilute mixtures with N2, is virtually independent of T. Under the same experimental conditions the stabilized SF−6 anion does not undergo autodetachment but the stabilized c‐C4F−6 anion undergoes a profound increase in autodetachment (by about four orders of magnitude). This difference between the SF−6 and the c‐C4F−6 anions is attributed to the larger electron affinity of the SF6 molecule compared to the c‐C4F6 molecule. The heat‐activated autodetachment for c‐C4F−6 is related to increases in the internal energy content of the c‐C4F−6 anion and is found to have an activation energy of 0.237 eV. The ‘‘limiting electric field strength’’ of SF6 was found to increase by ∼11% as T was increased from 300 to 600 K.
Membrane fouling caused by soluble microbial products in an activated sludge system under starvation

The behavior of soluble microbial products (SMP) and effects of SMP on membrane fouling under starvation of an activated sludge were studied. During a 16-day period, the experiment was investigated without nutrient addition to the closed system. Dissolved organic carbon (DOC) and molecular weight (MW) distributions of bulk solution were periodically monitored. The dead-end filtration tests were used to indicate the SMP effect on membrane fouling. Furthermore, the modified fouling index (MFI) was used to investigate the gel layer resistance of bulk solution closely related with the SMP. At last, an important increase in the concentrations of SMP with MW >10 kDa in the reactor was observed, which may be related to the cellular component degradation from endogenous metabolism. The gel layer resistance was observed to make the highest contribution to flux decline. Specially, the MFI is directly related to the concentration of high MW fraction. The SMP with MW >10 kDa was found to being strongly correlated wit.
Development of nanostructured lipid carriers for controlled delivery of mefenamic acid

This study was aimed to develop nanostructured lipid carriers (NLC) for the possible delivery of mefenamic acid. This study describes the effect of liquid lipid concentration on the characteristics of NLC such as particle size, polydispersity index, zeta potential, drug entrapment efficiency, and occlusivity index. Transmission electron microscopy revealed nearly spherical shape NLC with negligible effect of liquid lipid content on the particle morphology. The differential scanning calorimetry demonstrated a depression in the melting point and crystallinity index of the NLC with an increase in the amount of liquid lipid. The in vitro drug release studies demonstrated that solid lipid nanoparticle (0% oil), and NLC possessed a biphasic release pattern characterised by a rapid initial release followed by a sustained release, in comparison to nanoemulsions (100% oil) of which a nearly constant release was observed. Compared to NE and SLN, the excellent physical stability of NLC against drug leakage was seen.
Pressure broadening and cross relaxation of ammonia perturbed by hydrogen and helium: Implications on intermolecular potentials and discussion of rotational effects

The study of the absorption line profiles in the infrared region (6–7 μm), by means of a diode laser spectrometer and a FT spectrometer in ammonia diluted in He and H2 at room temperature, allowed us to determine pressure broadening cross section and the intradoublet inelastic rate (due to molecular inversion).
Determination of the Isosteric Heat of Adsorption of Hydrogen on the Multi-Walled Carbon Nanotubes

The isosteric heat of adsorption was used to study the interaction between hydrogen molecules and the Multi-Walled Carbon Nanotubes (MWCNTs). Characterizations of the MWCNTs sample were carried out based on the N2 adsorption isotherm at 77 K and the images from TEM and HRTEM. Step by step method was used to volumetrically measure hydrogen adsorption isotherms at equilibrium temperature-pressures from 123-310 K and 0-12.3 MPa. Isosteric heats of adsorption at seven excess adsorption amounts and that at zero surface loading were respectively determined by the slopes of the adsorption isosteres and the plot of the temperature dependence of the Henry’s constants. Results show that the limit of the isosteric heat of adsorption at zero surface loading is about and the mean under the experimental condition is about . The values are in the same grade as those of hydrogen on the activated coconut charcoal but smaller than those of hydrogen on the graphitized carbon black P33, the activated carbon AX-21 and the Single-Walled Carbon Nanotubes (SWCNTs). Conclusions are drawn that relatively lower adsorption amounts and the isosteric heat of hydrogen adsorption on the MWCNTs could be ascribed to the small specific surface area and the large mesopores.