Miracle-dz/UniFAR-FTUs huggingface dataset:
Problems in the Extraction of Polycyclic Aromatic Hydrocarbons from Diesel Particulate Matter

In this work, a comparison between Soxhlet, ultrasonic, and microwave-assisted extraction (MAE) (using hexane:acetone 1:1) of polycyclic aromatic hydrocarbons (PAHs) from SRM 1650 diesel particulate matter was made. As good recoveries were not obtained for the higher molecular weight compounds, MAE with toluene and dichloromethane was also tested. Achieved recoveries were compared with the results obtained in the same assays made with SRM 1648 urban particulate matter and real atmospheric particulate samples. In order to explain the difficulty of the extraction of PAHs from SRM 1650 in comparison to SRM 1648 and real atmospheric particulate samples, elemental analysis, X-ray diffraction, and particle analysis using scanning electron microscopy coupled to an automatic computer imaging system were also made. It is important to notice that SRM 1650 shows a high percentage of carbon and differences in the morphology of the particles between SRM 1650 and SRM 1648 were observed.
N-Methylated Diphenylguanidines: Conformations, Propeller-Type Molecular Chirality, and Construction of Water-Soluble Oligomers with Multilayered Aromatic Structures

The crystal structures of N,N‘-diphenylguanidine (1) and its N-methylated derivatives were investigated, and the conformational properties of these molecules were utilized to construct water-soluble oligomers with multilayered aromatic structures. N,N‘-Diphenylguanidine (1) afforded two types of crystals, chiral (P212121) and racemic (P21/c), upon recrystallization from EtOH. In both crystals, 1 exists in the (E,Z) conformation, in which one C−N bond (length: 1.28−1.30 A) attached to a phenyl ring shows double-bond character. In contrast, N,N‘-dimethyl-N,N‘-diphenylguanidine (4a) exists in the (Z,Z) conformation with the two aromatic rings facing each other. As judged from the crystal structures of several N-methylated compounds, the conformational preferences of diphenylguanidines appear to be related to those of aromatic anilides. N,N,N‘,N‘‘-Tetramethyl-N‘,N‘‘-diphenylguanidinium iodide (6) afforded chiral crystals, like 1 and N-methyl-N,N‘-diphenylguanidine (2). The absolute structure of each enantiom.
On the energies of low-lying excited electronic states of molecules

Two methods for calculating the energies of low-lying excited electronic states of molecules of the same symmetry as the ground state are compared. We term these the constrained variational method and the optimized trace method. Approximate solutions of the Schrodinger equation can be obtained by introducing finite basis set expansions. For each method two possibilities arise: (i) a common basis set can be used for the ground and the excited state; (ii) different basis sets can be employed for different states. Prototype calculations are reported for the hydrogen molecular ion using distributed basis sets of s-type Gaussian functions.
Crystal and molecular structure of glycyl-l-alanine hydrochloride

The crystal structure of glycyl-L-alanine hydrochloride C 5 N 2 O 3 H 11 CL, has been determined using three-dimensional photographic data. The crystals are monoclinic space group P2 1 , with cell demensions a=8.21, b=5.04, c=10.82 A and β=100.1°. Refinement was carried out by full-matrix least-sqrares methods with anisotropic thermal parameters for all non-hydrogen atoms to a final R index of 0.098 for 895 observed reflexions. The crystal structure is stabilized by a three-dimensinonal network if hydrogen bonds. Significant non-planarity of the peptide linkage with a torsion of 10.2° about the peptide bond has been observed. The conformation of the molecule has also been studied.
Hyperbranched Poly(amidoamine) as the Stabilizer and Reductant To Prepare Colloid Silver Nanoparticles in Situ and Their Antibacterial Activity

This study provided a facile and green method to prepare stable colloid silver nanoparticles in aqueous solution by utilizing the amine-terminated hyperbranched poly(amidoamine) (HPAMAM-NH2) as both stabilizer and reductant. The formation of silver nanoparticles was verified by FTIR, UV−vis, TEM, EDS, and XRD measurements. Monodispersed colloid silver nanoparticles with small particle sizes were obtained, and the average particle size could be effectively controlled from ca. 15 to 4 nm by simply adjusting the molar ratio of N/Ag in feed. The antibacterial activity of the HPAMAM-NH2/Ag nanocomposites was also investigated against Gram-positive and Gram-negative bacteria. They were able to efficiently inhibit the growth and multiplication of several bacteria, including Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella mobilis, and the bacterial inhibition ratio reached up to 95% at a low silver concentration of 2.7 μg/mL.
Configurational characteristics and scaling behavior of starburst molecules: a computational study

A kinetic growth model of starburst molecules having trifunctional branch points with flexible spacers of various stens between pairs of branch points is presented. The self avoiding walk algorithm grows all branches of the same generation simutaneously. For each spacer length, the intramolecular density profiles, radius of gyration of the molecule and the center to end distance of the branches are calculated as each generation is grown
Quantification of the Major Phenolic Compounds, Soluble Solid Content and Total Antioxidant Activity of Green Rooibos (Aspalathus Linearis) by Means of near Infrared Spectroscopy

Near infrared (NIR) spectroscopy was used to develop calibration models to predict aspalathin, nothofagin and dihydrochalcone contents of dried, green rooibos plant material, as well as to predict the aspalathin content of the respective water extracts. Calibration models were also developed to predict the total polyphenol content (TPC), soluble solid content (SSC) and total antioxidant activity (TAA) of the water extracts. Results showed that NIR spectroscopy can effectively predict the aspalathin content of dried, green rooibos with a standard error of prediction (SEP) and coefficient of determination (r2) of 0.45 g 100 g−1 and 0.85, respectively and the dihydrochalcone content of rooibos with an SEP of 0.49 g 100 g−1 and r2 of 0.87. After extending the aspalathin content range of the sample set, by adding varying amounts of a dried rooibos extract powder with high concentrations of aspalathin (15.95 g 100 −1) and nothofagin (1.94 g 100 g−1) to some samples, slightly less accurate, but more robust, models were obtained for the aspalathin (SEP = 0.53 g 100 g−1; r 2 = 0.87) and dihydrochalcone (SEP = 0.57 g 100 g−1; r 2 = 0.88) contents. The NIR calibration model developed for nothofagin content (SEP = 0.10 g 100 g−1; r 2 = 0.71) (extended range: SEP = 0.10 g 100 g−1; r 2 = 0.77) of dried, green rooibos is suitable for screening purposes. The current transmittance NIR calibration models developed for aspalathin content, TPC, SSC and the TAA of green rooibos water extracts did not give acceptable results.
Effect of Pressure on the Néel Temperature of MnCO3, CoCO3, and FeCO3

The effect of pressure on the Neel temperature of MnCO3, CoCO3, and FeCO3 is reported up to 10 kbar. Also the compressibilities of these materials have been measured at 4.2, 77, and 300°K. The shift of the Neel point has been measured through the mutual inductance of an astatic coil assembly containing the sample. The measured values of dTN/dP=+0.68, +0.11, and +≤0.1°K/kbar for MnCO3, CoCO3, and FeCO3 respectively. Combining the compressibility measurements with dTN/dP the value of magnetic Gruneisen constant γm=d log TN/d logV has been estimated for these compounds. The values of γm are found to be −11±4, −2.3±2, ≤ −5.3±3 for MnCO3, CoCO3, and FeCO3 respectively. Within the experimental error the value of γm for CoCO3 and for FeCO3 is close to −3.3, the value which Bloch has found for a number of 3d transition metal compounds showing superexchange coupling. However, the value of γm for MnCO3 is relatively higher and seems to be a combination of the volume dependence of at least two magnetic exchange inte.
Monitoring of Veterinary Drug Residues in Foods Produced in Korea

This study was conducted to monitor residues of 10 veterinary drugs in food products. Various veterinary drugs were examined including enrofloxacin, ciprofloxacin, norfloxacin, oxolinic acid, amoxicillin, ampicillin, oxytetracycline, tetracycline, chlortetracycline, and doxycycline in beef, pork, egg, chicken, eel, flatfish, and rockfish obtained from 6 different regions (Seoul, Incheon, Daejeon, Gwangju, Daegu, Busan). Residues were detected in 21 (6.5%) samples out of 321 samples. In particular, 2 (1.0%) livestock samples had detected residues among 203 products, and 19 (16.1%) aquaculture samples had residues detected among 118 products. The most frequently detected drug residues in aquaculture products were oxytetracycline and amoxicillin, but the levels were mostly below the MRL (Maximum Residue Limit). In only one flatfish sample, amoxicillin was found at a level higher than the MRL (0.05 mg/kg). In livestock products, residues of most veterinary drugs were not detected. But enrofloxacin was detected in 2 chicken (Korean name: Ogolgae) samples at a higher level than the MRL (0.1 mg/kg as the sum of ciprofloxacin).
Effect of steric hindrance on the rates and kinetic isotope effects of the reactions of 1-nitro-1-(4-nitrophenyl)alkanes with TBD and MTBD bases in THF

The rates of the reactions of 1-nitro-1-(4-nitrophenyl)alkanes and their deuteriated analogues with two bicyclic guanidines of comparable basicity, 1,5,7-triazabicyclo[4.4. 0]dec-5-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4. 0]dec-5-ene (MTBD), in tetrahydrofuran have been measured. The results are discussed in terms of the effects of steric hindrance in the C-acid and the base on the rates and deuterium kinetic isotope effects (KIEs). The reactions of TBD are 118–287 times faster than reactions of MTBD with the same nitroalkanes. The stabilization of the transition state of the TBD reactions by the N–H· · ·O hydrogen bond is plausible. With the most sterically crowded C-acid, the steric hindrance in the base gives a reduced deuterium KIE. Deuterium KIEs for the reactions of MTBD with various C-acids decreases with the steric hindrance in the C-acid but the reverse is true for TBD reactions. Results of this work disagree with the notion that steric hindrance leads to enhanced kinetic isotope effects.
Residual effect of phosphorus fertilizer when applied with the seed or banded

Abstract Measurements of equilibrium phosphate (P) potentials were used to estimate the residual effect of P fertilizer on soil samples taken in the fall from a fertility experiment. After the harvest of spring wheat (Triticum aestivum L.) samples taken over the fertilizer band showed lower P potentials (higher P activity) than samples taken from the unfertilized soil or from areas 6.25 cm away from the fertilizer band. The reduction of equilibrium P potential was proportional to the amount of P applied in the spring for rates up to 17.4 kg P/ha with no further changes when 26.1 kg P/ha was applied. Solubility diagrams for this soil indicated that, at the rates of P fertilization used in this study, the increase in soil P was controlled by sorption processes, and that only at rates more than twice the highest one used would the precipitation of Ca‐P compounds control the concentration of P in solution.
Effective Diffusion Coefficients of Soil Aggregates with Surface Skins

Dual-permeability model simulations and sensitivity studies indicate that preferential solute leaching in structured soil is intensified by a limited solute mass transfer between preferential flow paths and matrix. It is currently unknown how much aggregate skins may affect solute mass transfer. The objective of this study was to evaluate the effect of a skin layer on the effective diffusion coefficient, D e , of water saturated soil aggregates. In a diffusion experiment, the concentration decrease of Br - and Cl - in a solution being in contact with soil aggregates was measured. Aggregates with intact and removed surface skins were studied. Two different theoretical approaches were compared: (i) fitting a modified analytical solution of Crank for diffusion out of a solution of limited volume into a plane sheet to obtain D e for intact and for skin-removed aggregates; and (ii) calibrating a numerical solution for diffusion through a two-layer system to estimate D, of the skin layer and the interior part, separately. The D e -values of the skins differed for Br - and Cl - . Using the first approach, D e was six (Br - ) and 15 (Cl - ) times smaller for the intact than for the skin-removed aggregates. The second approach resulted in effective diffusion coefficients of the skin layer being 30 (Br - ) and 45 (Cl - ) times smaller than those of the interior parts. Aggregate skins may reduce diffusive anion transfer between interaggregate region and soil matrix, an effect which may significantly influence preferential solute transport in structured soil.
Déshydratation du methanol sur silice-alumine

A 420,5 °C la reaction du methanol sur un catalyseur silice-alumine est la meme que celle observee a plus basses temperatures :2 CH3 OH → CH3 OCH3 + H2 O. Entre 289 et 418 °C la cinetique de celle reaction n’obeit pas a la loi habituelle, l’ordre par rapport au methanol tendant vers la valeur un lorsque la temperature augmente. L’ensemble des faits experimentaux ne semble pas pouvoir etre interprete par un mecanisme simple du type Langmuir-Hinshelwood.
Site Preference and Si/B Mixing in Mixed-Alkali Borosilicate Glasses: A High-Resolution 11B and 17O NMR Study

In a series of mono and mixed-alkali borosilicate glasses (∼0.7M2O·B2O3·2SiO2, M = Li, Na, K, (1/2Li2O + ∼1/2Na2O), (1/2Li2O + 1/2K2O), and (∼1/2Na2O + 1/2K2O)), we have applied triple-quantum magic-angle spinning (3QMAS) and 11B and 17O NMR to obtain high-resolution information about short-range structure and the connections among various network structural units, to study the effect of mixed cations on the glass structure, and to explore the distribution and mixing of these modifier cations. For a Li-containing glass, a lower fraction of [4]B, a lower fraction of Si−O−B, and a higher fraction of nonbridging oxygen than those found in Na- and K-containing glasses suggests that there is a significant heterogeneity in terms of Si/B mixing in the former. For Li−Na and Li−K mixed cation glasses, anomalously high fractions of nonbridging oxygen were also observed along with smaller fractions of [4]B and Si−O−B, again indicating significant chemical heterogeneity. For Na−K mixed cation glasses, the populations.
Structural Study of Tin‐Doped Indium Oxide Thin Films Using X‐Ray Absorption Spectroscopy and X‐Ray Diffraction II . Tin Environment

Thin films of tin-doped In 2 O 3 (ITO for indium tin oxide) with different tin contents produced by a powder pyrolysis technique have been investigated by x-ray absorption spectroscopy and x-ray diffraction. In a previous paper, an extended x-ray absorption fine structure (EXAFS) study at the indium K-edge and diffraction measurements were presented. From the EXAFS investigations at the indium edge, it has been shown that the indium atomic environment becomes disordered during the doping process. In the present work, the EXAFS results at the tin K-edge and x-ray diffraction data are discussed. The EXAFS study confirms that the tin atoms are located at indium sites
Ultrasound Effects on Assembly of Glucagon Fibrils

In this work, we studied the ultrasound effect on the assembly of glucagon fibrils with Atomic force microscope (AFM) and fluorescence analysis. Experimental results showed that ultrasound can promote the formation of glucagon fibrils initially and thus drastically reduce the “lag time”. The growth rate of fibrils as well as their morphologies was remarkably dependent on an applied ultrasonic power. With increasing incubation time, glucagon fibrils became ununiform and showed segment-like shapes when a low-power ultrasound (<100 W) was applied. While at the action of a high-power ultrasound (180 W) fibrils were broken gradually and therefore more and more fragments were visualized using AFM. Finally, the modulating mechanism of ultrasound on glucagon fibrils formation was also briefly discussed.
Factors influencing critical flux in membrane filtration of activated sludge

Membrane filtration of biomass is usually accompanied by significant flux decline due to cake-layer formation and fouling. Crossflow filtration with flux controlled by pumping the permeate can produce stable fluxes if a ‘critical flux’ is not exceeded. Below critical flux the transmembrane pressure is typically very low and increases linearly with imposed flux. Above the critical flux the transmembrane pressure rises rapidly signifying cake-layer formation which is usually accompanied by a continued rise in transmembrane pressure and/or a drop in delivered flux. A range of microfiltration and ultrafiltration membranes with pore sizes from 0.22 to 0.65 µm and molecular weight cut-off of 100 kDa was used. The feed was an activated sludge mixed liquor with concentration in the range of 3–10 g dm−3. The results show that the critical flux depends on feed concentration and crossflow velocity, being higher for higher crossflow velocity or lower feed concentration. Critical flux was also dependent on membrane type, being lower for hydrophobic membranes. Although the transmembrane pressure was higher for the larger pore size membrane, no significant difference in critical flux was observed among different pore size membranes. © 1999 Society of Chemical Industry
A new splash cup to measure the kinetic energy of rainfall

Splash cups have long been successfully used for both the quantification of kinetic energy of rainfall and the detachability of soil particles by rainfall impact, the so-called “splash erosion”. Measurements of kinetic energy, however, have been difficult to operate in the field especially in remote areas, on steep slopes, and in forests since boundary conditions need to be controlled precisely. This paper introduces a new splash cup based on Ellison's archetype that reliably and accurately measures kinetic energy as a function of sand loss under a large variety of conditions. The Tubingen splash cup (T splash cup) is relatively easy to operate under harsh field conditions, and it can be used in experimental designs with a large number of plots and replications at reasonably low costs. The cup is constructed from plastic laboratory flasks and plastic pipes from water-supply equipments. The unit sand is held by a removable carrier system that can easily be replaced in the field. The splash cups have been calibrated in combination with a laser distrometer using a linear regression function with r2 = 0.98. They measure kinetic energy over a wide range of rainfall intensities from 0.6 to 40 L m–2 h–1. Kinetic energy per area varies between 10 and 250 J m–2. Two years of field test measurements in a subtropical forest ecosystem in China proved the reliability, durability, and usability of our new splash cups and allowed detecting differences in kinetic energy between different tree species and biodiversity levels.
Carbohydrate-protein interactions: structure, dynamics and free energy calculations

The current thesis presents work on the structure and dynamics of oligosaccharides and polysaccharides as well as the free energetics of carbohydrate-protein interactions. By applying various computational tools such as molecular dynamics simulations, our in-house fast sugar structure prediction software, replica exchange molecular dynamics, homology modeling, umbrella sampling, steered molecular dynamics as well as the thermodynamic integration formalism, we have been able to study the role of water on the surface of homopolysaccharides as well as complex oligosachharides, we have been able to produce a prediction of the bound structure of triantennary oligosaccride on the asialoglycoprotein receptor, we have been able to estimate the free energy of binding of Manα1→2Man to the HIV-1 inactivating protein, Cyanovirin-N as well as the relative binding free energies of mutants of Cyanovirin-N to the same ligand. Abstract Approved: Thesis SupervisorApproved: Thesis Supervisor Title and Department
Novel Amphoteric Cystine-Based Poly(amidoamine)s Responsive to Redox Stimuli

Novel poly(amidoamine)s (PAAs) containing disulfide linkages regularly arranged along the polymer chain, namely BP−CY and BAC−CY, were synthesized by stepwise polyaddition of l-cystine to 1,4-bis(acryloyl)piperazine (BP) and 2,2-bis(acrylamido)acetic acid (BAC), respectively. Even if l-cystine contains four acid hydrogens, no evidence of cross-linking was found. All products were characterized by 1H and 13C NMR spectroscopy, and their average molecular weight determined by size exclusion chromatography. The polymerization rates were investigated by means of 1H NMR spectroscopy. In both cases, the experimental data were consistent with pseudo-second-order kinetics. The calculated kinetic constants were kc,BP = 8.10 × 10-3 min-1 L mol-1 and kc,BAC = 1.41 × 10-3 min-1 L mol-1 for the polyaddition of l-cystine to BP and BAC, respectively. A potentiometric study was carried out of BP−CY and BAC−CY speciation as a function of pH, and the electrochemical activity of their disulfide bonds as a function of pH was .
Размерный эффект при образовании зарядового состояния в частицах природного клиноптилолита под воздействием электрического разряда

The processes of electrization of natural adsorbents – clinoptilolites with different particle sizes are studied. Electric charging of adsorbents was made by the effect of barrier discharge. The accumulation of electric charge in a material was detected by the thermally stimulated relaxation method. It is shown that when clinoptilolite particles become smaller, the surface density of the stored charge increases.
Composition and Source Apportionment of Organic Aerosol in Beirut, Lebanon, During Winter 2012

Fine organic aerosols were collected at a semi-urban site in Beirut, Lebanon, from 28 January to 12 February 2012 as part of the Emission and Chemistry of Organic Carbon in East Mediterranean-Beirut (ECOCEM-Beirut). A total of 20 quartz filter samples were collected on a 12 h basis using a high-volume sampler and were analyzed using a GC/MS technique. Levoglucosan was the major most abundant single component with an average value of 306 ng.m−3, followed by saturated and unsaturated carboxylic acids and sugars with average values of 234 and 118 ng.m−3, respectively. Reported values for other carboxylic acids, polycyclic aromatic hydrocarbons, and biogenic secondary organic aerosols (BSOA) were 87, 33 and 21 ng.m−3, respectively. Compared to a similar field campaign conducted in summer 2011, levoglucosan concentrations were lower in summer by a factor of 6, due to the use of wood burning for residential heating in winter. Concentrations of saturated and unsaturated carboxylic acids, other carboxylic acids, and BSOA were higher in summer by a factor of 3, 2, and 7, respectively. Higher concentrations observed for BSOA and other dicarboxylic acids during summer are due to higher biogenic emissions and greater photochemical activity in summer. Copyright 2013 American Association for Aerosol Research