Miracle-dz/UniFAR-FTUs huggingface dataset:
Deep chlorophyll maximum distribution in the central Tyrrhenian Sea described by a towed undulating vehicle

The towed undulating vehicle (TUV), named SARAGO, was used for two fine-scale surveys between the Italian and the Sardinian coasts during the Astraea 2 cruise (6–7 and 26–27 September 1995), studying the deep chlorophyll maximum distribution. SARAGO sections identify a sub-surface doming with higher chlorophyll a and primary production concentrations in the upwelling area of a cyclonic gyre region, detected by sea-surface temperature images. In the first section, the cyclone presents a double doming, in density and salinity, with shallower and concentrated patches of chlorophyll a for about 2 miles. Twenty days later, the second section shows that the gyre changes shape and extension, showing a single doming with higher primary production and chlorophyll a concentrations, distributed over a large area of about 40 nautical miles. SARAGO allows analysis of this high-variability phenomenon (cyclonic gyre) and allows concentrated patches (2 nm) to be identified, thus proving the importance of TUVs in the study of mesoscale processes.
Determination of Phenolic Antioxidants by HPLC with Amperometric Detection at a Nickel Phthalocyanine Polymer Modified Electrode

The suitability of nickel phthalocyanine polymer-coated glassy carbon electrodes for the amperometric detection of the phenolic antioxidants tert-butylhydroxytoluene (BHT), tert-butylhydroxyanisole (BHA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ), after their separation by HPLC under gradient elution conditions, is demonstrated. An applied potential of +0.70 V (vs. Ag/AgCl) was used, which offers the best signal-to-noise ratio and is considerably lower than those reported in the literature with conventional electrodes. A good separation of the four antioxidants was obtained in 17 min. Furthermore, no fouling of the electrode surface was observed when using the polymer modified electrode during the whole working day. Using TBHQ as internal standard, detection limits of 5.5 ng, 7.5 ng and 30 ng (for a 50-μL volume injected) were obtained for BHA, PG and BHT, respectively. As an application, the determination of the antioxidants contained in commercial chewing gum samples was carried out by applying a simple extraction procedure. It was demonstrated that only BHT was present as antioxidant in the samples, in a concentration of 51±3 μg g–1. Sample linearity and recovery studies, after adding a known amount of BHT to the analyzed samples, confirmed the sutability of the proposed method.
Biodegradation of Fungicide Tolclofos-methyl by Sphingomonas sp. 224

In order to decrease level of an organophosphorus fungicide, tolclofos-methyl, from in situ ginseng cultivating soil, we isolated a tolclofos-methyl degrading bacteria from ginseng cultivating soil samples. The bacterial strain removed tolclofos-methyl around 95% after 3 days incubation with complete liquid media. The strain was identified as Sphingomonas sp. by 16S rDNA sequence comparison, and designated as Sphingomonas sp. 224. Through the GC-MS analysis, Sphingomonas sp. 224 was proposed to have an initiative degradation pathway generating the metabolite such as 2,6-dichloro-4-methyl phenol compound from tolclofos-methyl. In addition, Sphingomonas sp. 224 was confirmed representing the effective degrading capability to tolclofosmethyl in situ soil.
Micro-Raman analysis for the identification of pigments from 19th and 20th century paintings

In this article, results using confocal µ-Raman to analyse the cross-section of paint samples are presented. Results obtained with light microscopy, scanning electron microscopy (SEM) combined with an energy dispersive X-ray analysis (EDX) and micro-X-ray fluorescence (µ-XRF) are mentioned and compared to the ones obtained with confocal (MRS). In some cases, pigment identification was possible only by combining analytical results from different techniques. The samples were drawn from five paintings belonging to the Academy of Fine Arts of Antwerp, which are part of a collection of 34 paintings made by students from the Academy between 1819 and 1920. Since, on the one hand, the painting techniques and materials, especially pigments, used in this period are still not completely known, and on the other hand, this collection constitutes a very important and reliable resource of information, these paintings were chosen for a systematic investigation. They represent the evolution of painting in Belgium over approximately a century. Copyright © 2008 John Wiley & Sons, Ltd.
Poly(alkyl/aryloxothiazenes): inorganic polymers with a sulfur(VI)-nitrogen backbone. Synthesis, characterization, and theoretical calculations

N-Silylsulfonimidates [Me 3 SiN=S(O)(R 1 )OR 2 , 3] with appropriate R 2 groups have been found to undergo thermally induced condensation to produce the sulfur(VI)-nitrogen backbone polymers poly(alkyl- or aryloxothiazeness), [N=S(O)R 1 ] n 4 and 5. Polymers 4 and 5 represent the first alkyloxothiazene polymers and the first characterized aryloxothiazenepolymers. Models after the well-known condensation of N-silylphosphoranimines to poly(phosphazenes), the polycondensation of 3 to 4 appears to be a fairly general reaction
Applications of Liquid-Solid Fluidization

Abstract Liquid fluidization of particulate solids has a history which predates the now more commonly applied gas fluidization. The broad range of operations to which liquid fluidization has found applications are summarized in this paper. These include classification of particles by size and density, a special case being sink-and-float separation by density; backwashing of granular filters and washing of soils; crystal growth; leaching and washing; adsorption and ion exchange; electrolysis with both inert and electrically conducting fluidized particles; liquid-fluidized bed heat exchangers and thermal energy storage; and bioreactors. Fluidized-bed bioreactors, which have received much attention during the past thirty years, are usually characterized by the catalytic use of enzymes or microbial cells that are immobilized by attachment, entrapment, encapsulation or self-aggregation. The most common application of such bioreactors is probably in wastewater treatment and, as in the case of the other operations mentioned above, liquid fluidization must in each case be weighed against competing schemes for achieving the same objective before it is adopted commercially.
SILICA NANOPARTICLES PRODUCED IN AEROSOL OT REVERSE MICROEMULSIONS: EFFECT OF BENZYL ALCOHOL ON PARTICLE SIZE AND POLYDISPERSITY

ABSTRACT Silica nanoparticles have been synthesized in AOT/decane/ammorium hydroxide reverse microemulsions via-base-catalyzed hydrolysis of tetraethoxysilano (TEOS). The effect of inter-micellar exchange has been investigated by conducting the synthesis experiments in the presence of benzyl alcohol (BA), an additive which is known to act as a cosurfactant at the water/oil interface, increasing the inter-micellar exchange rates. Larger, more monodisperse particles are formed at higher benzyl alcohol concentrations. Furthermore, the presence of high concentrations of benzyl alcohol (BA/AOT molar ratios larger than 1.5) promotes phase separation, probably due to the combined effects of the high benzyl alcohol content and the presence of ethanol (a product of the TEOS hydrolysis reaction). The effects of benzyl alcohol concentration on particle size and size distribution have been attributed to the inhibition of nucleation by fast rearrangement of hydrolyzed TEOS species.
Biorefinery in a pulp mill: simultaneous production of cellulosic fibers from Eucalyptus globulus by soda-anthraquinone cooking and surface-active agents

Abstract Industrial Eucalyptus globulus wood chips were submitted to different autohydrolysis conditions followed by kraft cooking and soda-anthraquinone cooking. The autohydrolyzed wood chips were much easier to delignify than the control wood chips. Soda-anthraquinone cooking could be performed at a cooking temperature that was 20°C lower than that for the kraft cooking on control wood chips. Furthermore, the active alkali could be reduced. The resulting unbleached pulps reacted as well to oxygen delignification as the control pulps and could be further bleached to 90% ISO brightness with a D(EP)D sequence. The autohydrolysis liquors were investigated for their suitability as a source for the synthesis of alkylpolyxylosides (APX). These surface-active agents are synthesized through the reaction between the saccharides of the autohydrolysates and a fatty alcohol, with the former being the hydrophilic and the latter being the hydrophobic part of the molecule. The impact of the substances detected in autohydrolysates on the APX synthesis was studied. It was demonstrated that lignin dissolved during autohydrolysis should at least partially be removed before the production of APX.
Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate

A facile one-pot synthesis of methyl 5-(4-chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate (4) is described. The title compound was efficiently synthesized by the reaction of phenyl hydrazine, dimethyl acetylenedicarboxylate and 4-chlorobenzoyl chloride in dichloromethane under reflux in good yield. The structure of the target compound was deduced by modern spectroscopic and analytical techniques and unequivocally confirmed by a single crystal X-ray diffraction analysis. The crystal of the title compound belongs to orthorhombic system, space group P 21 21 21 with cell parameters a = 6.6491(3) A, b = 7.9627(6) A, c = 30.621(5) A, α = β = γ = 90° and Z = 4. The crystal packing of the compound (4) is stabilized by an offset π-stacking between the planar benzoyl-substituted diazole moieties.
Characterization of cyanide in a natural stream impacted by gold mining activities in the Witwatersrand Basin, South Africa

Water systems in the Witwatersrand Basin are heavily contaminated with pollutants from gold-mine tailing leachates and spillages. Cyanide speciation was studied in relation to the Natalspruit, a natural stream within a gold mining area of Johannesburg. The part of the studied stream was adjacent to an abandoned gold-mine tailings dump. The results of this study pointed to a variation in surface and groundwater chemistry. The groundwater had low pH and contained elevated concentrations of pollutants including secondary cyanide species, e.g. thiocyanate, cyanate, and ammonium. Metal-cyanide complexes that are weak-acid dissociable (CNWAD) and strong-acid dissociable (CNSAD) cyanides were found to dominate the speciation of cyanide, with iron cyanide complexes being most prevalent in groundwater. Decreases in the concentration of 63% for , 83% for , 69% for , and 47% for were observed from groundwater to surface water largely due to dilution and dissociation (in the case of the first two complexes). Speciation modeling was used to estimate the concentrations of CNWAD and CNSAD based on total cyanide (CNT), total metal, and total anion concentrations. Other cyanide complexes as well as dominant sulfate complexes were also predicted.
NO oxidation on plasma pretreated Pyrex: the case for a distribution of reactivity of adsorbed O atoms

The formation of NO2 molecules on a Pyrex surface, as a result of NO oxidation by adsorbed O atoms on the wall, is experimentally demonstrated and quantified. The measurements reveal that the characteristic times of heterogeneous NO2 production and NO gas phase decay change from ∼60 to ∼1500 s as the gas phase concentration of NO introduced in a tube pretreated with an oxygen radiofrequency discharge increases from 1013 to 1015 cm−3. Moreover, a clear variation of the characteristic loss frequency of NO molecules when small amounts of NO are successively injected in the tube is detected, between ∼7 × 10−2 and ∼5 × 10−3 s−1. The complex surface kinetics observed is studied and interpreted with the help of a mesoscopic surface model accounting for Eley–Rideal NO oxidation and slow NO2 adsorption, confirming the existence of adsorption sites possessing a distribution of reactivity on the surface.
Effect of uniaxial strain on the Drude weight of graphene

We study the dependence on the strength and orientation of applied uniaxial strain of the Drude weight in the conductivity of graphene. We find a non-monotonic dependence on strain, which may be related to the proximity to several strain-induced electronic topological transitions. Given the relation between the Drude weight and the long-wavelength plasmon frequency, such a strain dependence can be evidenced by infrared spectroscopy measurements.
Derivation of soil quality criteria using predicted chemical speciation of Pb2+ and Cu2+

A review is made of soil toxicological data that report soil total lead or copper in combination with soil pH. Using these data, free metal activities in the soil solution of those tests are estimated using published regressions that describe the relationships between metal activities and the total metal content, pH, and soil organic matter content. The toxicological significance of the predicted free metal activities is compared to that of total metal contents. In a majority of cases, estimated free metal activity improves the prediction for toxic effects on crops, soil organisms, or soil microbial processes. The free metal activity level corresponding to a defined level of risk can be used to derive a pH‐dependent soil criterion for total metal content that should generate a soil solution‐free metal activity below the determined critical level.
Oscillator strengths of Cr I lines lying between 200 and 541 nm from hook-method and absorption measurements in a furnace

Oscillator strengths of 148 transitions in the neutral chromium atom with wavelengths between 200 and 541 nm were determined in a high-temperature furnace by use of the hook and absorption methods for strong and weak lines, respectively. 114 of these gf-values are reported for the first time. Hook spectra taken at wavelengths near 430 nm assured accurate knowledge of the product of f-value and column density for prominent transitions with lower levels lying at 0 and ≈ 1 eV. The absolute scale is based on the best available oscillator strengths for the 427 nm resonance triplet. The relative scale matches measurements of the relative intensities of emission lines that correspond to transitions from a common upper level (z5P02) to the ground level (a 7S3) as well as to excited terms (a5S, a5D). A slight adjustment (well within the calibration uncertainties) made our oscillator-strength scale agree with gf-values obtained by Cocke, Stark & Evans from beam-foil and branching-ratio measurements. Uncertainty estimates, given for each oscillator strength, are substantiated by the agreement (within error limits) of those f-values that could be measured by both, absorption and hook method.
Pollution‐enhanced reactive chlorine chemistry in the eastern tropical Atlantic boundary layer

This study examines atmospheric reactive chlorine chemistry at the Cape Verde Atmospheric Observatory in the eastern tropical Atlantic. During May–June, 2007, Cl2 levels ranged from below detection (∼2 ppt) to 30 ppt. Elevated Cl2 was associated with high HNO3 (40 to 120 ppt) in polluted continental outflow transported in the marine boundary layer (MBL) to the site. Lower Cl2 was observed in recently subsided air masses with multiday free tropospheric oceanic trajectories and in air containing Saharan dust. Model simulations show that the observations of elevated Cl2 in polluted marine air are consistent with initiation of Cl chemistry by OH + HCl and subsequent heterogeneous, autocatalytic Cl cycling involving marine aerosols. Model estimates suggest that Cl atom reactions significantly impact the fates of methane and dimethylsulfide at Cape Verde and are moderately important for ozone cycling.
Polymer dispersed liquid crystals for display application

Abstract An overview of polymer dispersed liquid crystal (PDLC) materials, their physical properties, and potential applications in the optic and electrooptic industry is presented. These optoelectronic materials have unique properties which are expected to expand liquid crystal technology into new display and light shutter applications. Recent research by small and large industrial and university laboratories on device physics and chemistry has provided substantial progress towards the commercialization of these materials. Work to date on such features as response times, switching voltage, and contrast as well as material preparation procedures and unique optical characteristics will be reviewed. These materials are also of interest to basic physics because of new kinds of physical phenomena brought on by the confinement of a nematic liquid crystal to small submicron-size droplets. Enhanced surface-to-volume ratio, large nematic deformations and problems associated with molecular anchoring at a polymer w.
An Analysis of the Field Dependence of Interface Trap Generation under Negative Bias Temperature Instability Stress using Wentzel–Kramers–Brillouin with Density Gradient Method

In this paper, the Si–H bond dissociation rate is calculated under a negative bias temperature instability (NBTI) condition that considers the quantum effect on the hole density in the inversion layer of a metal–oxide–semiconductor field-effect transistor (MOSFET). The physical model used in this study is composed of two terms: the number of holes in that Si–H bond, and the polarization of the Si–H bond under an external electric field. By adopting a density-gradient (DG) method with a penetration boundary condition and the Wentzel–Kramers–Brillouin (WKB) approximation, the penetrated hole density profile in the gate oxide and the tendency towards the hole amount in the Si–H bond according to the electric field have been identified and compared with other works. The results show that the NBTI field dependence and the lifetime of the devices under NBTI stress correlate to the power-law dependency.
Metabolic profiling reveals growth stage variability in diatom exudates

We studied the patterns of waterborne metabolites released by diatom cultures during different growth phases. A carefully optimized enrichment procedure for metabolites from seawater medium facilitated the generation of large‐scale sample sets that could be used for metabolic profiling. Samples from cartridge enrichments were directly submitted to ultraperformance liquid chromatography (UPLC) coupled with time‐of‐flight mass spectrometry (TOF‐MS). Metabolic profiling revealed distinct patterns of metabolite release depending on the growth phases of the major bloom‐forming diatoms Skeletonema marinoi and Thalassiosira pseudonana. Principal component analysis (PCA) enabled the recognition of specific metabolites that were only temporarily released by growing algal cultures. The exometabolome of the cells was complex and variable. The kinetics of metabolite release of some compounds resembles those of signal molecules involved in quorum sensing by bacteria. The introduced exometabolome investigation will help unravel the implications of release patterns of potential infochemicals for plankton ecology.
MEASUREMENT OF CEFTRIAXONE IN PERITONEAL DIALYSIS SOLUTIONS BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Abstract A simple, rapid, and reproducible reverse phase high-performance liquid chromatographic method for the measurement of ceftriaxone in peritoneal dialysis solutions is described. the mobile phase contained acetonitrile, phosphate buffer, deionized water and an ion pair agent. the samples were injected onto a C18 column and detector was set at 280 nm. the retention time for ceftriaxone and the internal standard was 7.04 and 3.74 min, stability of ceftriaxone was 12 hours in each dialysis solution at 37°C (Table 3).
Core–Shell Synthesis of a Novel, Spherical, Mesoporous Silica/Platinum Nanocomposite: Pt/PVP@MCM‐41

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Production of no-carrier-added 123I via heavy-ion activation of natural antimony oxide

Activation of natural Sb2O3 with 48 MeV 7Li3+ beam results in the formation of no-carrier-added 123I in the matrix along with the radionuclides 123,125Xe and 122Sb. The 123I yield amounts to about 400 kBq/μAh and the radionuclidic impurity of 124I to ∼1.2% of 123I. Attempts to separate no-carrier-added iodine from bulk antimony target involved liquid-liquid extraction with TOA and HDEHP as well as precipitation of Sb2S3 with thioacetamide. The precipitation technique was found to be the most effective for quantitative separation of 123I from the bulk antimony oxide target.
Self-assembly of β-sheet forming peptides into chiral fibrillar aggregates

The authors introduce a novel mid-resolution off-lattice coarse-grained model to investigate the self-assembly of beta-sheet forming peptides. The model retains most of the peptide backbone degrees of freedom as well as one interaction center describing the side chains. The peptide consists of a core of alternating hydrophobic and hydrophilic residues, capped by two oppositely charged residues. Nonbonded interactions are described by Lennard-Jones and Coulombic terms. The influence of different levels of "hydrophobic" and "steric" forces between the side chains of the peptides on the thermodynamics and kinetics of aggregation was investigated using Langevin dynamics. The model is simple enough to allow the simulation of systems consisting of hundreds of peptides, while remaining realistic enough to successfully lead to the formation of chiral, ordered beta tapes, ribbons, as well as higher order fibrillar aggregates.
Demonstration of Blue and Green GaN-Based Vertical-Cavity Surface-Emitting Lasers by Current Injection at Room Temperature

We realized room-temperature lasing of blue and green GaN-based vertical-cavity surface-emitting lasers (VCSELs), for the first time, by current injection. The blue GaN-based VCSEL had a threshold current of 1.5 mA and a threshold voltage of 3.3 V under continuous-wave operation. Its maximum output power was 0.70 mW and its laser emission wavelength was 451 nm. The green GaN-based VCSEL had a threshold current of 22 mA and a threshold voltage of 6.3 V under pulsed current operation. Its maximum output power was estimated to be over 0.80 mW and the laser emission wavelength was 503 nm.
International Journal of Food Engineering Rheology of Selected Persian Honeys

The rheological properties of two types of Persian honeys (Thyme and Shahjahan) were studied over temperature and water content of 10-30°C and 16.8-17.2%, respectively. At these conditions, they exhibited a Newtonian behavior for shear rate in range of 0-100 and apparent viscosity in range of 6.7 and 150 Pa.s. The activation energy, glass transition temperature and glass viscosity of Thyme and Shahjahan honeys were (104.5 and 109.7 kJ/mol), (225.6 and 228.2K), and (1.68 x 1011 and 1.48 x 1011 Pa.s), respectively. The Williams-Landel-Ferry (WLF) and Arrhenius Models used to check the dependency of viscosity and temperature data. The results showed that Thyme and Shahjahan honeys were fitted with WLF much better than Arrhenius model. However, the viscosity and water content data did not match with exponential model of Zaitoun, and the viscosity decreased with water content due to its plasticizing effect.