Miracle-dz/UniFAR-FTUs huggingface dataset:
Photochemical Formation of Hydroxyl Radical by Constituents of Natural Waters

A new method is employed to determine the rates of photochemical hydroxyl radical (OH) formation in aqueous solutions and in natural waters under both aerobic and anaerobic conditions. Quantum yields for OH formation from the photolysis of nitrate and nitrite obtained by this method are in good agreement with previous measurements. Photolysis of Suwannee River fulvic acid (SRFA) solutions produced the hydroxyl radical under anaerobic conditions in proportion to the SRFA concentration. Under aerobic conditions, the quantum yields for OH formation were slightly higher and exhibited a different wavelength dependence than those obtained under anaerobic conditions. Experiments employing catalase indicate that Fenton chemistry can account for at most 50% of the total signal under aerobic conditions for SRFA irradiated at 310 and 320 nm. These results indicate the presence of a dioxygen-independent pathway of hydroxyl radical production that cannot be assigned to nitrate/nitrite photolysis or to Fenton chemistry.
Swelling kinetics of polymers

Abstract The equilibrium swelling of semicrystalline or crosslinked polymers and of their gels upon immersion in liquids has been investigated extensively. On the other hand, few studies have dealt with the kinetics of swelling. Swelling kinetics are important for designing controlled-release devices for drugs and agricultural pesticides based on swellable polymer matrices, and for predicting the release rates of the active ingredients. Theoretical considerations, based on diffusion-controlled swelling, show that first-order kinetics does not apply, even though deviations during the initial and even middle stages of the swelling process may be relatively small. Extensive studies of swelling rate and equilibrium swelling of supported and unsupported gelatin films have been published. The rate is controlled by stress relaxation in the swelling polymer network. The rate equations of these studies, which have also been reported to apply to cellulose, are shown to represent second-order kinetics with respect t.
Surface Behavior of Polyamide 6 Modified by Barrier Plasma in Oxygen and Nitrogen

Polyamide (PA) 6 was modified by diffuse coplanar surface barrier discharge (DCSBD) plasma in an atmosphere of nitrogen and oxygen. The surface roughness decrease of PA 6 was detected by AFM and nano-indentation after modification in DCSBD plasma. A significant increase in O/C and N/C ratios of plasma-modified PA 6 using XPS analysis was found. The results show the importance of introducing oxygenic polar functional groups on the polymeric surface in order to increase its surface energy during a short time of plasma activation. The modification of PA 6 by DCSBD oxygen plasma was more efficient than by nitrogen plasma.
Anisotropy of the dielectric constants of trigonal selenium and tellurium between 3 and 30 eV

The reflectivity of Se and Te single crystals has been measured at near normal incidence for photon energies between 3 and 30 eV with the electric field vector lying parallel and perpendicular to the c-axis of the crystals. The measurements were made using the polarized continuum of the synchrotron radiation of DESY. A Kramers-Kronig analysis gave the optical constants for both directions of polarization. For both substances electron energy loss measurements are reported. Comparison with optical data gives satisfactory agreement. Even at high energies considerable anisotropic behaviour and several new spectral features are observed. They are discussed in terms of recent band structure calculations. Die Reflektivitat von Se- und Te- Einkristallen wurde fur Photonenenergien zwischen 3 und 30 eV bei nahezu senkrechtem Einfall mit dem elektrischen Feldvektor parallel und senkrecht zur c-Achse der Kristalle gemessen. Fur diese Experimente wurde das polarisierte Kontinuum der Synchrotronstrahlung von DESY benutzt. Eine Kramers-Kronig Analyse lieferte die optischen Konstanten fur beide Polarisationsrichtungen. Fur beide Substanzen wird uber Elektronenenergieverlustmessungen berichtet. Der Vergleich mit den optischen Daten ergibt eine befriedigende Ubereinstimmung. Auch bei hohen Energien werden fur beide Substanzen ein betrachtliches anisotropes Verhalten und mehrere neue Strukturen beobachtet. Sie werden an Hand von neuen Bandstruktur-Rechnungen diskutiert.
Crystal and magnetic structure of NiMnGe

NiMnGe is investigated by means of X-ray diffraction, neutron diffraction, and magnetometric methods. The orthorhombic distorsion of hexagonal lattice is observed below 470 K. The compound NiMnGe is antiferromagnetic with a Neel temperature TN = 346 K. The jump observed at temperature Tt = 185 K on the temperature dependence of magnetic susceptibility points at the change of a magnetic structure. From the analysis of the neutron diffraction patterns the following models of spiral magnetic structure are obtained; at T < Tt the spiral axis is in the bc-plane. The angle between the spiral axis and the b-axis is 45°, magnetic moment at 80 K is 2. 75μB; at Tt < T < TN the spiral axis is along the a-axis. The magnetic moment at 295 K is 2. 2μB.
Trace element content and magnetic properties of commercial HOPG samples studied by ion beam microscopy and SQUID magnetometry

In this study, the impurity concentration and magnetic response of nine highly oriented pyrolytic graphite (HOPG) samples with different grades and from different providers were determined using ion beam microscopy and SQUID magnetometry. Apart from sideface contaminations in the as-received state, bulk contamination of the samples in most cases consists of disk-shaped micron-sized particles made of Ti and V with an additional Fe contamination around the grain perimeter. The saturation magnetization typically increases with Fe concentration, however, there is no simple correlation between Fe content and magnetic moment. The saturation magnetization of one, respectively six, out of nine samples clearly exceeds the maximum contribution from pure Fe or Fe3C. For most samples the temperature dependence of the remanence decreases linearly with T – a dependence found previously for defect-induced magnetism (DIM) in HOPG. We conclude that apart from magnetic impurities, additional contribution to the ferromagnetic magnetization exists in pristine HOPG in agreement with previous studies. A comparative study between the results of ion beam microscopy and the commonly used EDX analysis shows clearly that EDX is not a reliable method for quantitative trace elemental analysis in graphite, clarifying weaknesses and discrepancies in the element concentrations given in the recent literature.
Cross sections for electron capture from atomic hydrogen by fully stripped ions in the 0.05--1.00 a.u. impact velocity range

Abstract We have calculated electron capture cross sections from atomic hydrogen with the molecular approach to atomic collisions for impact velocities between 0.05 and 1 a.u. The projectile ions are H+, He2+, Li3+, Be4+, B5+, C6+, N7+, and O8+. For the four most strongly populated capture channels, cross sections are tabulated for each value of the final quantum numbersn,l,m, summed overmfor the givennandland overlandmfor the givenn.
Growth and characterization of nanocrystalline CdSe thin films deposited by the successive ionic layer adsorption and reaction method

The successive ionic layer adsorption and reaction method was used to deposit CdSe thin films on glass substrates at room temperature (300 K). The films were characterized by x-ray diffraction, energy dispersive x-ray analysis, scanning electron microscopy, atomic force microscopy and high-resolution transmission electron microscopy. Optical absorption and electrical resistivity were measured. The CdSe layer grew with nanocrystalline cubic phase along with some amorphous phase present in CdSe film, with an optical band gap 'Eg' of 2.1 eV and room temperature electrical resistivity of the order of 106 ? cm.
Separation of Mg, Ca and Fe from geological reference materials for stable isotope ratio analyses by MC-ICP-MS and double-spike TIMS

Near quantitative separation of analyte elements from the sample matrix is commonly required to obtain precise and accurate stable isotope data, especially if MC-ICP-MS is used in conjunction with the standard-sample bracketing (SSB) technique for mass bias drift correction. Here, we report a robust procedure that allows for the combined chemical separation of Mg, Ca and Fe, using ion-exchange columns that contain 1 ml AG50W-X8 (200–400 mesh) cation exchange resin. Magnesium was separated for isotope ratio analyses from many geological sample types by a single pass through this column. For Mg purification, Be, Ti, Mn, Fe and Al are selectively eluted using dilute HF and an acetone–HCl mixture. The separation of Mg from Ca-dominated carbonate samples and/or a combination of Mg, Ca and Fe separation from the same sample aliquot, is achieved by the adsorption of Ca and Fe onto the ion-exchange resin from 10 M HCl. Following purification, geological reference materials, including water, bone, carbonate and sediment samples, igneous and sedimentary rocks and a chondritic meteorite were analysed by MC-ICP-MS (Mg and Fe isotopes) and double-spike TIMS (Ca isotopes). Average external repeatabilities were ±0.16‰ for 26Mg/24Mg, ±0.26‰ for 44Ca/40Ca and ±0.05‰ for 56Fe/54Fe (2sd; n ≥ 5). Comparison with published data documents the accuracy of the results. For Mg isotope analyses using SSB-MC-ICP-MS, matrix-induced mass bias effects were studied using element additions. The artificial matrices left a memory in subsequent standard analyses, likely due to depositions on the cones. This observation allowed for the detection of matrix effects in unknown samples. Finally, the current status of Mg and Ca zero-delta reference materials is briefly discussed.
Kinetics of the hydrolysis and condensation of organofunctional alkoxysilanes: a review.

A review of the literature is presented for the hydrolysis of alkoxysilane esters and for the condensation of silanols in solution or with surfaces. Studies using mono-, di-, and trifunctional silane esters and silanols with different alkyl substituents are used to discuss the steric and electronic effects of alkyl substitution on the reaction rates and kinetics. The influences of acids, bases, pH, solvent, and temperature on the reaction kinetics are examined. Using these rate data, Taft equations and Bronsted plots are constructed and then used to discuss the mechanisms for acid and base-catalyzed hydrolysis of silane esters and condensation of silanols. Practical implications for using organofunctional silane esters and silanols in industrial applications are presented.
Synthesis of Well-Crystalline Lattice Carbon Nanotubes via Neutralized Cooling Method

In this contribution, vertically aligned carbon nanotubes were synthesized by chemical vapor deposition (CVD). The effects of intrinsic disorders constructed by mobile surface contaminants on the structural perfection of carbon nanotubes (CNTs) were investigated. The results indicated a complete picture on the effect of the involved parameters on the lattice defects of modulated CNTs based on the cooling step. Raman scattering showed that the different cooling methods of the CVD preforms altered the bound complex defects of the structure of the CNTs. Moreover, an array of CNTs was removed from the silicon substrate by applying the neutralized cooling method on the CVD, while the vertical and parallel orientations were retained. The FESEM images, coupled with Raman spectroscopy results, confirm the morphological improvements of the growth CNTs based on the neutralized cooling method.
Molecular dynamics simulations of a protein in the canonical ensemble

We report the results of constant energy (microcanocial ensemble) and constant temperature (canonical ensemble) molecular dynamics simulations of bovine pancreatic trypsin inhibitor. The constant temperature simulations were carried out by using either Langevin dynamics or one of three extended system (ES) methods: a single Nose-Hoover thermostat, a single Nose-Hoover chain, and massive Nose-Hoover chains (one chain coupled to each degree of freedom). We evaluate the abilities of the different methdos to provide temperature control and examine their effects on kinetic energy equipartitioning rates, averages structures and fluctuations, and dynamical properties
Interfacial Restructuring of Ionic Liquids Determined by Sum-Frequency Generation Spectroscopy and X-Ray Reflectivity

Surface sum-frequency generation spectroscopy and X-ray reflectivity were used to study the surface of [BMIM][X] ionic liquids (BMIM = 1-butyl-3-methylimidazolium cation, X = BF4−, PF6−, and I−). Sum-frequency signal strength from the terminal methyl groups of the cation at the surface indicates that the topmost surface of these ionic liquids is occupied by polar-oriented hydrophobic butyl chains having approximately 1/3 of the in-plane density of fully packed alkyl chains as observed by the same method for the hexadecanol Langmuir monolayer. X-ray reflectivity data reveal a layer with density larger than that of bulk. However, the reflectivity is not sufficiently sensitive to the exact location of this layer either at the vacuum interface or sandwiched between the bulk and the low-density alkyl chain, as observed in the sum-frequency measurements. Analysis of the reflectivity data in conjunction with the sum-frequency spectra strongly suggests the molecules forming the topmost layer are on average polar-.
Mapping contaminated soils: using remotely‐sensed hyperspectral data to predict pH

This study assessed the feasibility of remote mapping and, thus, monitoring of soils contaminated by acid mine drainage. We report on the use of laboratory and airborne spectroscopy to determine pH. Reflectance spectra were obtained for rock and soil samples collected at our test site, the abandoned Brukunga Pyrite Mine in South Australia, using a laboratory‐based Analytical Spectral Devices Inc. (ASD) spectroradiometer. A partial least squares (PLS) regression was used to develop a predictive equation for pH based on the reflectance spectra. The validation results indicated that it is possible to generate satisfactory predictions of pH from spectral data, as demonstrated by the ratio of performance to deviation (RPD) of 1.53, a relatively small root mean square error of prediction (RMSE) of 0.91 and an R2 value of 0.58. Evaluation of the predictive equation indicated that it depends on diagnostic spectral features related to secondary iron minerals resulting from acid mine drainage (AMD). The presence of these minerals was validated independently using X‐ray diffraction (XRD). The predictive equation was applied to airborne hyperspectral data, using a form of remote sensing that simultaneously acquires spatially co‐registered images in many spectrally contiguous bands (> 50). Hyperspectral data acquired by the HyMap sensor between 1998 and 2001 were used to produce multi‐temporal pH maps. Despite the inaccuracy of the global positioning system (GPS), locations of the validation samples and geographical inaccuracy of the airborne imagery, validation of the maps indicated that pH can be generated reliably from airborne hyperspectral data, as indicated by the relatively small RMSE of 0.57 and the R2 value of 0.72. These maps demonstrate the potential to provide environmental practitioners, including soil scientists, with a spatially comprehensive view of pH related to AMD conditions. This has implications for the application of remotely sensed hyperspectral data for monitoring soil pH related to AMD conditions, especially in the near future when such data will be available from satellite sensors such EnMap (Stuffler et al., 2009). Some examples of their use include a better understanding of the progress of restoration efforts and or to pinpoint areas where future efforts should be concentrated and to evaluate the extent of downstream impacts, including contamination of soil. More generically, soil pH data are routinely required by soil scientists as part of the suite of data for understanding soil characteristics and the ability to provide spatially comprehensive soil pH data, as demonstrated by this study, would be valuable.
Measurement and Modeling of Th Sorption onto TiO2

The sorption and desorption of Th onto TiO(2) (10 g/L) was studied as a function of pH (1-11), ionic strength (0.005-0.1 M NaCl, NaClO(4)), thorium concentration (from 1 x 10(-9) to 3 x 10(-2) M), and carbonate concentration (up to 10(-2) M) using (234)Th tracer. The results indicate the reversible formation of an inner sphere complex with a strong pH dependence. No effect of the carbonate on sorption could be measured in the pH range investigated (5-10.5). The data were fitted with five different conceptual models (constant capacitance, diffuse layer, Stern, triple layer, and a nonelectrostatic model) using FITEQL. Different hydroxy complex surface reactions were tried, one at a time, varying the site density (1-12 sites/nm(2)). The reaction that provided the best fit depended strongly on the surface site density and the model used. To be able to fit a reaction to the pH-dependent data with the compact layer models, the effect of the electrostatic term had to be decreased by decreasing the site density below 5 sites/nm(2). None of the electrostatic models could be used to fit all of the isotherm data. The nonelectrostatic model could be used to reasonably fit both the pH-dependent and isotherm data. Copyright 1999 Academic Press.
Influence of Potassium Rates and Sources on Seed Cotton Yield and Yield Components of Some Elite Cotton Cultivars

Abstract A field experiment was conducted at Central Cotton Research Institute, Multan, Pakistan on Miani soil series, silt loam soil (Calcaric, Cambisols and fine silty, mixed Hyperthermic Fluventic Haplocambids) to assess the response of four cotton (Gossypium hirsutum L.) cultivars to potassium (K) fertilization. The treatments consisted of four cotton cultivars (CIM-448, CIM-1100, NIAB-Karishma, S-12), four potassium rates (0, 62.5, 125, 250 kg K ha−1), and two sources of potassium fertilizer [muriate of potash (KCl) and sulphate of potash (K2SO4)]. The cotton cultivars differed significantly in response to various potassium fertilizer levels and its sources with respect to seed cotton yield and its components. The highest yield was obtained with the application of 250-kg K ha−1, however, it was economical to add 125 kg K ha−1. Seed cotton yield of cv. CIM-448 was considerably greater than that of the other cultivars in K-unfertilized treatments, which was related to cultivar differences in K uptake efficiency in utilizing native potassium nutrient. Potassium added as muriate of potash caused a significant depression in seed cotton yield than that of sulphate of potash. The increase in yield seemed to have resulted largely from the higher K concentration of leaf tissues at bloom stage and available soil-K because of potassium application. A significant relationship between the yield and number of bolls per plant (r = 0.92**) and boll weight (r = 0.85**) indicated that these two growth attributes were responsible for enhancing the quantum of final harvest of seed cotton.
Polysaccharide biomaterials for drug delivery and regenerative engineering

Polymers derived from plant (polysaccharides) and animal (proteins) kingdoms have been widely used for a variety of biomedical applications including drug delivery and tissue regeneration. These polymers due to their biochemical similarity with human extracellular matrix components are readily recognized and accepted by the body. Natural polymers inherit numerous advantages including natural abundance, relative ease of isolation, and room for chemical modification to meet varying technological needs. In addition, these polymers undergo enzymatic and/or hydrolytic degradation in biologic environments into non-toxic degradation byproducts. Polysaccharides (carbohydrates) are often isolated and purified from renewable sources including plants, animals, and microorganisms. Majority of these polymers are found in the extracellular matrix components of organisms and participate in inter and intracellular cell signaling and contribute to their growth. All these features offer polysaccharide-based biomaterials much desired biological recognition, biocompatibility, and bioactivity. In spite of many merits as biomaterials, these polysaccharides suffer from drawbacks including variations in material properties based on source, microbial contamination, uncontrolled water uptake, poor mechanical strength, and unpredictable degradation patterns. These inconsistencies have limited the usage of polysaccharides and biomedical application related technology development. Many of these polysaccharides have been chemically modified to achieve consistent physicochemical properties including mechanical stability, degradation, and bioactivity and processed into microparticles, hydrogels, and 3D porous structures for tissue regeneration applications. Presence of multiple functionalities on the polymer backbone allows easy structure modifications for the required application. The current article focuses on the application of polysaccharide-based materials in regenerative engineering and delivery. Copyright © 2014 John Wiley & Sons, Ltd.
Yield Response of Corn to Single and Combined Application of Cattle Manure and Urea

A 2-year field experiment was conducted to evaluate the single- and combined-application effects of cattle manure and urea on corn (Zea mays L.) production. A randomized complete block design was conducted with five nitrogen (N) rates (36, 72, 108, 144, and 180 kg N ha−1) as urea, cattle manure, or both. The stover yield and aboveground biomass increased with urea application up to 144 kg N ha−1 but remained unchanged at greater N rates. At all N rates, combined application of manure and urea resulted in greater grain yields than single applications. Crop response to applied N was greater in the combined N application system than in the single-application treatments. The greatest grain yield was found in plots that had received a combination of 18 ton manure ha−1 plus 160 kg urea ha−1. Manure application along with urea enhanced crop yield response to urea and reduced its application rate.
Evaluation of Toxicity and Gene Expression Changes Triggered by Oxide Nanoparticles

Several studies have demonstrated that nanoparticles (NPs) have toxic effects on cultured cell lines, yet there are no clear data describing the overall molecular changes induced by NPs currently in use for human applications. In this study, the in vitro cytotoxicity of three oxide NPs of around 100 nm size, namely, mesoporous silica (MCM-41), iron oxide (-NPs), and zinc oxide (ZnO-NPs), was evaluated in the human embryonic kidney cell line HEK293. Cell viability assays demonstrated that 100 MCM-41, 100 , and 12.5 ZnO exhibited 20% reductions in HEK293 cell viability in 24 hrs. DNA microarray analysis was performed on cells treated with these oxide NPs and further validated by real time PCR to understand cytotoxic changes occurring at the molecular level. Microarray analysis of NP-treated cells identified a number of up- and down-regulated genes that were found to be associated with inflammation, stress, and the cell death and defense response. At both the cellular and molecular levels, the toxicity was observed in the following order: ZnO-NPs > -NPs > MCM-41. In conclusion, our study provides important information regarding the toxicity of these three commonly used oxide NPs, which should be useful in future biomedical applications of these nanoparticles.