Miracle-dz/UniFAR-FTUs huggingface dataset:
Demographic characteristics of 3 Artemisia tridentata Nutt. subspecies

Previous research suggested that woody plant recruitment may occur in pulses in semi-arid areas. The overall objective of this study was to determine if this pulse phenomena was recorded in the demographic structures of big sagebrush (Artemisia tridentata Nutt.) stands in Wyoming. In 1997, approximately 75 stem cross sections were collected from 9 stands of each of 3 subspecies of big sagebrush in Wyoming along elevation and climatic gradients. Annual growth-rings were used to identify year of establishment and demographic characteristics were analyzed from age-class frequencies. Mean stand ages of the 3 subspecies were different (P = 0.002), and analyses revealed that Wyoming (A. tridentata ssp. wyomingensis) and mountain big sagebrush (A. tridentata ssp. vaseyana) stand ages (32 +/- 9 and 26 +/- 9 years, respectively) were significantly older than basin big sagebrush (A. tridentata ssp. tridentata) (17 +/- 3) stands (P < 0.05). Mean recruitment intervals (years) were shorter for basin (1.6) than for Wyoming (2.3) and mountain (2.2) sagebrush (P = 0.01). The number of cohorts did not differ among the subspecies (P = 0.11), but the percent of years with recruitment was significantly higher for basin (59%) compared to Wyoming (37%) and mountain (39%) subspecies (P < 0.0001). Age-class frequency distributions of each stand and regional stand combination were assessed for dispersion across each associated period of record. Chi-square goodness-of-fit tests were performed for the negative binomial distribution. All stands (with one exception) and all 3 regional stand combinations fit the negative binomial distribution. Age-class frequency patterns indicate that recruitment is clustered or aggregated across each period of record. Recruitment in big sagebrush stands occurs in pulses throughout Wyoming. DOI:10.2458/azu_jrm_v54i2_perryman
Rate coefficients for the gas-phase reaction of OH radicals with selected dihydroxybenzenes and benzoquinones

Rate coefficients have been determined for the gas-phase reaction of the hydroxyl (OH) radical with the aromatic dihydroxy compounds 1,2-dihydroxybenzene, 1,2-dihydroxy-3-methylbenzene and 1,2-dihydroxy-4-methylbenzene as well as the two benzoquinone derivatives 1,4-benzoquinone and methyl-1,4-benzoquinone. The measurements were performed in a large-volume photoreactor at (300 ± 5) K in 760 Torr of synthetic air using the relative kinetic technique. The rate coefficients obtained using isoprene, 1,3-butadiene, and E-2-butene as reference hydrocarbons are kOH(1,2-dihydroxybenzene) = (1.04 ± 0.21) × 10−10 cm3 s−1, kOH(1,2-dihydroxy-3-methylbenzene) = (2.05 ± 0.43) × 10−10 cm3 s−1, kOH(1,2-dihydroxy-4-methylbenzene) = (1.56 ± 0.33) × 10−10 cm3 s−1, kOH(1,4-benzoquinone) = (4.6 ± 0.9) × 10−12 cm3 s−1, kOH(methyl-1,4-benzoquinone) = (2.35 ± 0.47) × 10−11 cm3 s−1. This study represents the first determination of OH radical reaction-rate coefficients for these compounds. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 696–702, 2000
Infrared Spectroscopic Evidence for the Ice Formation Mechanisms Active in Aerosol Flow Tubes

Interest in quantifying processes of ice formation in the atmosphere has led to the recent development of new laboratory techniques, including an aerosol flow tube (AFT) reactor employed for the study of the ice nucleation kinetics of suspended submicrometer aqueous particles. The AFT technique employs an infrared (IR) beam along the flow tube axis. Spectral changes between 700 and 6000 cm−1 indicate the formation of ice at sufficiently cool temperatures. Apparent freezing temperatures are determined as a function of condensed-phase mole fraction composition. A typical aqueous chemical system is (NH4)2SO4/H2O. The mole fraction composition of the condensed-phase of this aerosol is determined by the ratio of the integrated spectroscopic bands for H2O and SO42–. A key uncertainty in the AFT-IR technique is the freezing mechanism, and knowledge of the mechanism is essential to estimate homogeneous nucleation rates (J, cm−3 s−1) from observed apparent freezing temperatures. The current work provides observational and modeling spectral evidence, based upon changes in the scattering component of the recorded IR extinction spectra with temperature, that observed ice freezing events at warmer temperatures arise from the following mechanism: relatively few particles in the aerosol freeze (e.g., 1 in 106) and this primary event is followed by rapid scavenging of water vapor to grow the few ice particles into large ice particles observed in the IR spectra. Correspondingly, the remaining aqueous particles partially evaporate. In contrast, the spectral evidence provides support that a modified mechanism is operative at cooler temperatures: the ice freezing event consists of the freezing of a much larger fraction of the particles (e.g., 1 in 10) accompanied by a much less important vapor-phase mass transfer event.
Calculations of molecules, clusters, and solids with a simplified LCAO-DFT-LDA scheme

A simplified LCAO-DFT-LDA scheme for calculations of structure and electronic structure of large molecules, clusters, and solids is presented. Forces on the atoms are calculated in a semiempirical way considering the electronic states. The small computational effort of this treatment allows one to perform molecular dynamics (MD) simulations of molecules and clusters up to a few hundred atoms as well as corresponding simulations of condensed systems within the Born-Oppenheimer approximation. The accuracy of the method is illustrated by the results of calculations for a series of small molecules and clusters. © 1996 John Wiley & Sons, Inc.
Biofilm Formation by Escherichia coli csgA and fimA mutants

Biofilms are a structured community of bacterial cells enclosed in a self-produced polymeric matrix and adherent to an inert or living surface. These structures and the organisms that cause them can pose a very serious problem if they colonize on medical devices. This is because biofilms have the ability to communicate within the colony and with other organisms that might attach to the surface, acting like a community working together. Biofilms allow the organism to be resistant to harsh and unfavorable conditions allowing them to survive longer and spread. Several genes in Escherichia coli (E. coli) have been associated with biofilm formation by that organism. Many of those genes encode surface appendages such as flagella, fimbriae, and pili. We created mutations in genes encoding curli (csgA) and fimbriae (fimA) with the aim of comparing their ability to form biofilms. The respective genes were selected on kanamycincontaining agar and disrupted with a kanamycin resistance gene. Biofilm formation in nutrientrich medium and nutrient-poor medium is currently in progress, and the ability of the mutant E. coli strains to form biofilms will be compared with that of the parent wild type strain using a crystal violet microplate assay. 2 Journal of Undergraduate Research at Minnesota State University, Mankato, Vol. 14 [2014], Art. 9 http://cornerstone.lib. mnsu.edu/jur/vol14/iss1/9
Synthesis and Vibrational Spectroscopic Study of Some Metal(II) Halide and Tetracyanonickelate Complexes of Isonicotinic Acid

The M(IN)2Ni(CN)4 [where M: Cu, Mn, Zn, IN: Isonicotinic acid, abbreviated to M-Ni-IN] tetracyanonickelate and some metal halide complexes with the following stoichiometries: Cu(IN)X2 (X:Br,I), Cd(IN)2X2, (X:Cl,Br), and Zn(IN)4X2 (X:Br,I) were synthesized for the first time. Their FT-IR spectra were reported in the 4000-400 cm-1 region. Vibrational assignments were given for all the observed bands. The analysis of the vibrational spectra indicates that there are some structure-spectrum correlations. For a given series of isomorphous complexes, the sum of the difference between the values of the vibrational modes of uncoordinated isonicotinic acid that were coordinated to the metal ion isonicotinic acid was investigated and found to depend on the halogen for a given metal. The proposed structure of tetracyanonickelate complexes consists of polymeric layers of |M-Ni (CN)4|\infty with the isonicotinic acid molecules bound directly to the metal (M) atoms. Certain chemical formulae were determined using the elemental analysis results.
Effect of film thickness on the physical properties of ZnO:Al thin films deposited using a spray pyrolysis technique

ZnO:Al(ZAO) films with various amount of solution, in the range 10–120 mL, were prepared on a glass substrate. Deposition was carried out using a spray method, and the substrate temperature was held at 500 °C. It was found that increasing the amount of solution causes the ZnO:Al thin films to exhibit a strong orientation along (002). The variation in the structural properties due to variation in the volume of solution was investigated by means of X-ray diffraction. The lowest sheet resistance obtained was 40 Ω/cm2 for a 120 mL solution. PACS Nos.: 73.61. –r, 78.20. –e
Influence of the stiffness of the measurement system on the elastic adhesional contact

An elastic contact theory is described to reveal the effects of the stiffness of the measurement system on the adhesion behavior. The point contact is treated in an elastic continuum limit, taking into account the energy change from the surface to the interface within the contact region. The contact area is determined under Hertz's assumptions. The stiffness of the measurement system is taken into account and the total energy is defined as Etotal = Eelastic + Einterface + Estiffness. The contact radius, the displacement, the force, and the total energy are normalized and their relationships are discussed. In the limit when the stiffness is infinite, our approach conforms to the Johnson-Kendall-Roberts (JKR) theory. The force at the initial contact is discussed as well as the force required to separate samples. The ratio of these forces can be written as a function of only one parameter (κ), which is concerned with the stiffness. A simple asymptotic relation is derived between the force ratio and the param.
Mechanism and kinetics of reduction of a FeO-Fe2O3-CaO-MgO aluminosilicate melt in a high-CO-activity environment

Abstract Droplets of an iron-bearing calcia magnesia aluminosilicate (Fe-CMAS) melt were reacted under distinctly reducing conditions (fO₂ = 2.4 × 10-13 and 6.4 × 10-15 atm) at high temperature (~1400 °C) and ambient pressure. The low fO₂ environment was maintained by a flowing gas mixture of CO and CO2, with a high content of CO. Molten metallic iron alloyed with silicon and carbon formed on the surface of the melt; no metal was observed in sample interiors. A color change from brown to pale blue confined to the outer layer of the melt indicated that essentially complete reduction of Fe3+ to Fe2+ had occurred in this region. Analysis of the reaction kinetics, particularly in comparison to melts of similar polymerization but free of CaO, reveals that the concentration of electron holes has decreased to such an extent that ionic transport in the melt is significantly slowed and the diffusion of CO as a neutral species becomes dominant and rate-limiting: molecular CO, initially incorporated into the melt as a physically dissolved species, subsequently reacts to form chemically dissolved (bonded into the melt structure) CO32- anions, consuming electron holes in the process. The chemical diffusion coefficient for CO in the reduced melt at 1400 °C is estimated as DCO ≈ 4 × 10-4 cm2/s, consistent with that of other, similarly sized molecular species (e.g., H2 and H2O) for similarly polymerized melts, as reported by other investigators. Upon quenching, the droplet acts as a closed system. Internal redox couples see the reduction of the carbonate so as to form bubbles of CO, the composition of which are confirmed with Raman spectroscopy. The open-system reduction and closed-system quenching dynamics are analyzed following an Ellingham-diagram approach.
On-line photodecomposition for the determination of antimony species

On-line UV photooxidation by peroxodisulfate was coupled to ion chromatography hydride generation atomic fluorescence spectroscopy (IC-UV-HG-AFS) for the speciation of inorganic antimony [Sb(III) and Sb(V)] and methylated species. Several parameters (UV lamp, irradiation time and peroxodisulfate concentration) that greatly influence the sensitivity of these three antimony species were investigated in depth. Under optimized conditions, photodecomposition resulted in an improvement in methylantimony species sensitivity. Dilution in di-ammonium tartrate medium was necessary in order to ensure short-term stability of Sb(III) at the µg l−1 concentration level. Furthermore, the efficiency of irradiation was strongly dependent on the chemical composition of the measured solution. Detection limits of 0.04 µg l−1 for Sb(V), 0.03 µg l−1 for Me3SbCl2 and 0.03 µg l−1 for Sb(III) as well as repeatability and reproducibility better than 4 and 8% RSD, respectively, were obtained. The proposed methodology was applied for antimony speciation in terrestrial plant sample extracts. Copyright © 2005 John Wiley & Sons, Ltd.
Nitrate retention and leaching in variable charge soils of a watershed in São Paulo state, Brazil

Abstract Two Oxisols [Dusky Latosol (LR) and Dark‐Red Latosol (LE)] and one Entisol [Quartzous Sand (AQ)] of a watershed situated at the boundaries of the most important Brazilian aquifer, and intensively cropped to sugarcane, were studied in relation to their nitrate retention and leaching potential, and related electrochemical properties. Nitrate leaching tests carried out with repacked soil columns showed that deep layers of the subsoils, in which electrochemical conditions favor nitrate retention (e.g., net charge near zero, and ZPC larger than pH in water) required a larger number of pore volumes (npv) of leaching solutions for nitrate peak elution and nitrate depletion than surface layers, in which nitrate retention is not favored. Well defined regions of nitrate accumulation were detected in the 220–460 cm layer in the LE and 40–600 cm layer in the AQ. In these regions nitrate concentrations varied from 0.06 to 0.22 and 0.08 to 0.20 cmolc kg‐1, against 0.03 to 0.05 cmolc kg‐1 in the upper and underlayers. Nitrate distribution curves in the LE profile in the years 1995 and 1997 presented similar shapes and positions, indicating that the accumulation region remained almost unaltered, and stationary, in this period. Nitrate accumulation was related to soil electrochemical conditions favorable to nitrate retention.
Influence of coating properties on the adhesion of proteins to atmospheric plasma modified surfaces

Protein adhesion is of key importance for the biocompatibility of medical devices. This study investigates the adsorption of protein, bovine serum albumin (BSA), onto both uncoated silicon wafers and nanometre thick fluorosiloxane coated wafers. A plasma polymerised coating was deposited from a mixture of tetramethylcyclotetrasiloxane (TC) and perfluorooctyltriethoxysilane (FS) (1:1 by vol. ratio). The liquid precursor mixture was nebulised into an atmospheric plasma jet formed using the PlasmaStream TM system. The adsorption of protein on the plasma polymerised coatings was evaluated under dynamic flow conditions using a spectroscopic ellipsometry technique. The rate of protein adsorption onto coated and uncoated silicon wafer substrates was monitored over time after the BSA solution was introduced into a flow cell. These measurements indicated the adsorption of a 2 nm thick BSA protein layer on the uncoated silicon wafers. The ellipsometry thickness measurements of adsorbed protein on silicon wafer were confirmed using quartz crystal microbalance measurements (QCM). The BSA adsorption studies were then repeated with a fluorosiloxane coating. These coatings exhibited a highly textured surface morphology with low surface energy and a high water contact angle of 156 . The ellipsometry flow cell tests with BSA indicated almost no adsorption of protein onto the superhydrophobic fluorosiloxane coating. This study demonstrated the ability of ellipsometry to measure protein adsorption under dynamic flow Confirmation of BSA protein adsorption on silicon was carried out by FTIR analysis of the uncoated silicon used in liquid cell tests. Analysis indicated the presence of both the Amide I band at 1650 and Amide II band at 1550 cm -1 present in BSA protein Confirmation of adsorbed protein thickness on the silicon wafer was carried out by quartz crystal microbalance measurement. Measurements were carried out on crystals composed of a 50 nm SiO 2 layer on top of a 100 nm gold substrate. On analysis of the change in crystal resonance frequency, the Sauerbrey equation [24] was fitted to the data and a determination of film thickness made.
Degradação de benzeno, tolueno e xilenos em águas contaminadas por gasolina, utilizando-se processos foto-Fenton

In this work the potentiality of photo-Fenton processes were investigated toward the degradation of aromatic hydrocarbons (BTXs) from water contaminated with gasoline. The main results demonstrated that BTXs can be quickly degraded by photo-Fenton process assisted by solar or artificial UV-A radiation, degradation that leads to generation of characteristic phenolic transient species (ie. phenol, hydroquinone and catechol). In the treatment of contaminated water by photo-Fenton processes assisted by solar light, complete BTXs removal was observed in reaction times of about 5 min. Mineralization of about 90% was also observed by applying a multiple H2O2 addition system.
Pharmacophore mapping, molecular docking and QSAR studies of structurally diverse compounds as CYP2B6 inhibitors

Pharmacophore mapping, molecular docking and quantitative structure–activity relationship (QSAR) studies were carried out for a structurally diverse set of 48 compounds as CYP2B6 inhibitors. The generated best pharmacophore hypotheses from the three methods of conformer generation (FAST, BEST and conformer algorithm based on energy screening and recursive buildup) indicate the importance of two features, namely, hydrogen bond acceptor [electron-rich centre] and ring aromaticity. The distance between the two centres of the important features for ideal inhibitors varied from 5.82 to 6.03 Å. The chemometric tools used for the QSAR analysis were genetic function approximation (GFA) and genetic partial least squares. The developed QSAR models indicate the importance of an electron-rich centre, size of molecule, impact of branching and ring system and distribution of charges in the molecular surface. The docking study confirms the importance of an electron-rich centre for binding with the iron atom of the cytochrome enzyme. A GFA model with spline option was found to be the best model based on internal validation as well as the r 2 m (overall) criterion (Q 2 = 0.772, r 2 m (overall) = 0.774). According to the external prediction statistics (R 2 pred = 0.876), another GFA-derived model with spline option outperforms the remaining models.
An efficient one‐pot synthesis of pyridazinones and phthalazinones using HY‐zeolite

The first one-pot synthesis of pyridazinones and phthalazinones from arenes, cyclic anhydrides, and ArNHNH2 in the presence of efficient recyclable heterogeneous catalyst, HY-zeolite, in high yield and short reaction time is reported. J. Heterocyclic Chem., (2011).
A new simple UV-Vis spectrophotometric method for determination of sulfite species in vegetables and dried fruits using a preconcentration process

A new eco-friendly, selective and sensitive method was developed for preconcentration and determination of trace levels of sulfite by ultrasonic-assisted cloud point extraction (UA-CPE). The method is based on the selective ion-association of the anionic complex, Cu(SO3)22−, produced depending on sulfite concentration in the presence of excess Cu(II) ions with toluidine blue (TB+) at pH 7.5, and then extraction of the formed ion-associate complex into the surfactant rich phase of Triton X-45 micelles. Under the optimized reagent conditions, the calibration curve is linear in range of 2.5–350 μg L−1, and the limits of detection and quantification of the method (LOD and LOQ) (3σblank/m and 10σblank/m) are 1.15 and 3.82 μg L−1 with a sensitivity enhancement factor of 95. The results demonstrated that the method achieved acceptable quantitative recoveries of 95.7–102.9% with relative standard deviations (RSDs) of 2.1–4.8%. The method showed good selectivity, and was successfully applied to the quantification of sulfite species in vegetable and dried fruit samples with satisfactory results. The results were compared with those of the standard 5,5′-dithio-bis(2-nitrobenzoic acid) (DTNB) method, and the two paired t-test was used to determine whether the results obtained by the two methods differ significantly.
Preparation of polyurethaneurea (PUU) uniform spheres by SPG membrane emulsification technique

Uniform polyurethaneurea (PUU) spheres were prepared from 20–40 wt % urethane prepolymer (UP) solution of xylene. Uniform droplets were formed with the Shirasu porous glass (SPG) membranes of 1.42, 5.25, and 9.5 μm pore size, dispersed in an aqueous phase with dissolved stabilizers, and allowed to stand for the chain extension at the room temperature with diamines that were added after the emulsification. The reaction progressed rapidly by an addition of ethyl acetate to the aqueous phase, promoting the diffusion of diamines into the droplets. The reaction of —NCO groups with water did not hamper the emulsification process, which normally occurred in 1 to 2 h, yielding stable droplets with the coefficient of variation around 10%. No instability or coagulation occurred, while standing for the chain extension, and solid, spherical PUU particles of 5–20 μm were obtained after removal of the solvent. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2237–2245, 2000
Spectroscopic and theoretical studies on the excited state in diimine dithiolate complexes of platinum(II)

The photophysical properties of a series of Pt(N-N)(S-S) complexes have been studied where (N-N) is either an [alpha],[alpha][prime]-diimine or saturated diamine chelating ligand and (S-S) is either a dithiolate chelating ligand or two monothiolate ligands in order to determine the orbital composition of the excited state. The solvent dependence of the absorption spectra of these complexes and the temperature dependence of their emission intensities and lifetimes have been examined while the ligands have been systematically varied. The electronic spectra are found to be dependent on whether or not the nitrogen chelating ligand is unsaturated (contains a vacant [pi]* orbital). On the basis of the spectroscopic data, the lowest energy absorption band in the diimine complexes is assigned as a metal-dithiolate to [pi]*(diimine) transition, whereas in the diamine complexes it is assigned as a metal-to-dithiolate MLCT transition. The only room-temperature emissive complexes are those that contain an [alpha],[alpha][prime]-diimine chelating ligand. The nature of the emission in these complexes at all temperatures depends on the dithiolate ligand, and the temperature dependence of the emission spectra has been examined. The nature of the HOMO and LUMO has been examined experimentally using cyclic voltammetry. On the basis of the electrochemical and spectroscopic data, themore » emission from all of the Pt(diimine)(S-S) complexes except those of 1,2-dithiolate maleonitriledithiolate (mnt) is assigned as a [sup 3](d(Pt)/p(S)-[pi]*(diimine)) transition, while, for the mnt complexes, it corresponds to a [sup 3](d(Pt)/p(S)-[pi]*(mnt)) transition. These assignments are supported by extended Hueckel molecular orbital calculations. « less