Miracle-dz/UniFAR-FTUs huggingface dataset:
Effects of fertilizer type and rate on labile soil fractions of a sandy Cambisol—long‐term and short‐term dynamics

The application of density fractionation is an established technique, but studies on short-term dynamics of labile soil fractions are scarce. Objectives were (1) to quantify the long-term and short-term dynamics of soil C and N in light fraction (LFOC, LFON, ρ ≤ 2.0 g cm- 3 ) and microbial biomass C (C mic ) in a sandy Cambisol as affected by 28 y of different fertilization and (2) to determine the incorporation of C 4 -C into these labile fractions during one growing season of amaranth. The treatments were: straw incorporation plus application of mineral fertilizer (MSI) and application of farmyard manure (FYM) each at high (MSI H , FYM H , 140-150kg N ha -1 y -1 ) and low (MSI L , FYM L , 50-60 kg N ha- 1 y -1 ) rates at four field replicates. For all three sampling dates in 2008 (March, May, and September), stocks of LFOC, LFON and C mic decreased in the order FYM H > FYM L > MSI H , MSI L . However, statistical significance varied markedly among the sampling dates, e.g., with LFOC being significantly different (p≤ 0.05) in the order given above (sampling date in March), significantly different depending on the fertilizer type (May), or non-significant (September). The high proportion of LFOC on the stocks of soil organic C (45% to 55%) indicated the low capacity of soil-organic-matter stabilization on mineral surfaces in the sandy Cambisol. The incorporation of C 4 -C in the LFOC during one growing season of amaranth was small in all four treatments with C 4 -LFOC ranging from 2.1 % to 3.0% of total LFOC in March 2009, and apparent turnover times of C 3 -derived LFOC ranged from 21 to 32 y for the sandy soils studied. Overall, our study indicates that stocks of LFOC and LFON in a sandy arable soil are temporarily too variable to obtain robust significant treatment effects of fertilizer type and rate at common agricultural practices within a season, despite the use of bulked six individual cores per plot, a common number of field replicates of four, and a length of treatments (28 y) in the order of the turnover time (21-32 y) of C 3 -derived LFOC.
Liquid Chromatography - Mass Spectrometry of Zwitterionic Liquids

Liquid Chromatography - Mass Spectrometry of Zwitterionic Liquids We have implemented full mass spectrometric assay of several 3-(1-alkyl-2-methylimidazolio)propanesulfonates, which are known as zwitterionic liquids (ZILs). Hydrophilic interaction liquid chromatography (HILIC) column and different mobile phases in both isocratic and gradient elution conditions were used for separation of the compounds present in these samples. The structures of the impurities have been confirmed by LC-MS/MS experiments. In addition, fragmentation pathways of ZILs were studied for different collision energies (0-50 eV) in positive electrospray ionization (ESI) mode under collision-induced dissociation conditions. Several new routes of fragmentation are briefly discussed. These include possible rearrangements and imidazolium ring expansions, which hypothetically proceed through carbocationic intermediates in the gas phase. Currently these processes are studied in a more detailed fashion. Cviterjonu Šķidrumu Hromatogrāfija-Masspektrometrija Veiktie hromatogrāfiskie pētījumi parāda, ka cviterjonu šķidrumu (CJŠ) un tajos esošo galveno piemaisījumu atdalīšanai acetonitrilu saturošās kustīgās fāzes ir piemērotākas par eluentiem, kuros ir metanols. Lietojot eluenta gradientu, ir iespējams analīzi veikt ātrāk, kā arī uzlabojas hromatogrāfisko joslu forma. AEŠH apvienojumā ar masspektrometriju ļauj noteikt piemaisījumus CJŠ, kā arī noskaidrot to fragmentēšanās maršrutus pat, ja šo piemaisījumu struktūra ir visai līdzīga. Galvenie jonu veidošanās ceļi ietver lādiņa inducēto disociāciju, ja sadursmju energija ir maza, un homolītisko alkilķēdes šķelšanos, ja sadursmju energija ir augsta. Augstas sadursmju energijas gadījumā novēro parādības, ko nosaka karbkatjonu īpašības gāzes fāzē; tās ietver secīgas cikla paplašināšanās stadijas, ko veicina ūdeņraža pārnese. Tomēr pilnīgai fragmentēšanās mehānismu noskaidrošanai nepieciešami jonu masu mērījumi ar augstu precizitāti vai eksperimenti ar izotopus saturošiem savienojumiem.
Investigation of the bonding mechanism in pyrite using the Mössbauer effect and X-ray crystallography

The nature of the bonding in pyrite is considered in relation to the origin of the quadrupole splitting observed by means of the Mossbauer effect and the angular variation of the recoil-free fraction. It is found that neither crystal-field effects nor non-stoichiometry are enough to account for the observed splitting. Consideration of molecular orbital effects, however, shows that a very small amount of electron delocalization is enough to cause the observed splitting because of the strong effects the valence electrons have on the iron nucleus. It is also found that, contrary to previously published data, the recoil-free fraction is practically independent of angle. This result is derived from both Mossbauer resonance measurements and an X-ray structure determination. The structure determination confirms earlier reports of interatomic distances and angles and also determines the anisotropic thermal parameters for both Fe and S atoms in naturally occurring pyrite. The temperature variation of the isomer shift is measured and interpreted to mean that vibrational modes corresponding to Raman modes are not excited in the pyrite lattice between 10 and 300 K. This complements published IR spectra which show no such modes between 190 and 660 cm-1 (equivalent to 274 and 950 K). The isomer shift of pyrite is found to be 0.074 ± 0.001 mm/s relative to Fe in Cu (source and absorber at room temperature) and the quadrupole splitting is 0.634 ± 0.006 mm/s at room temperature. The ratio of intensities of the 3/2 → ½ and ½ → ½ transitions of the Mossbauer spectra was typically 1.004 ± 0.011.
Design and performance of an ultrahigh vacuum system for metallic multilayers

This article describes the design, development, and performance testing of a versatile ultrahigh vacuum (UHV) electron-beam deposition system for synthesis of thin films and multilayer structures. Initially, basic design norms required to achieve set objectives are discussed and then a brief description of the system is presented. The fabricated UHV chamber has a number of vacuum ports to accommodate various features and accessories needed to deposit and characterize good quality thin films and multilayer structures of different metals. To demonstrate the capabilities of the system, depositions of thin films and multilayer structures of different materials were carried out. Representative results of hard x-ray reflectivity measurements corresponding to Ni, Au, and Ag thin films and Nb/Si and Fe/Ni multilayer structures are given and discussed. Furthermore, the easy adaptability of the system in order to carry out other investigations related to thin films is also demonstrated by presenting our recent in s.
Gastro‐resistant controlled release of OTC encapsulated in alginate/chitosan matrix coated with acryl‐EZE® MP in fluidized bed

A gastro-resistant system of acryl-EZE® MP coated alginate/chitosan microparticles was developed to improve the controlled release of oxytetracycline (OTC). Microparticles were obtained by complex coacervation and, thereafter, were coated using fluidized polymer dispersion with acryl-EZE® MP solution. OTC distribution inside the microparticles was determined by multiphoton confocal microscopy, demonstrating the efficiency of encapsulation process. In vitro OTC release kinetic was performed in order to obtain the release profile in gastric and intestinal simulated fluids. A fast initial release, or burst effect, was observed with uncoated microparticles loaded with OTC in gastric conditions. When a 50% mass increase in acryl-EZE® MP coating was achieved, OTC release in acidic medium was greatly reduced, resulting in the expected gastro-resistant effect. Different mathematical models were applied to describe the drug diffusion across the polymer matrix. The Logistic model was the best tool to interpret the experimental data in most of the systems studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40444.
HPLC-UV and LC-MS-MS Characterization of Silymarin in Milk Thistle Seeds and Corresponding Products

Abstract A HPLC analytical protocol for the separation of taxifolin, silychristin, silydianin, silybinin A, silybinin B, isosilybinin A, and isosilybinin B was developed. The gradient method used a combination of water and methanol as the eluent, and the separation was monitored at 290 nm. The authenticity of the reference compounds was correctly analyzed by liquid chromatography-mass spectrometry-mass spectrometry and by spiking HPLC experiments. The dihydroflavonol taxifolin and the flavanolignans silychristin, silydianin, and silybinin A and B were extracted from two milk thistle (Silybum marianum(L.) Gaertn. ) seed batches using organic solvents, and subsequently quantified by the developed method. Both seed batches differed in their silydianin, silybinin A, and silybinin B contents. Taxifolin and the flavanolignans were also quantified in finished products, where the ratio of the silybinin compounds was similar in tested Brands A and B. Brand A was first extracted in a Soxhlet with ethanol. Under these conditions, Brand A was short of the silymarin content on its label. The same product was then extracted in room temperature ethanol, and was shown to contain 152 mg of silymarin, 12 mg more than was indicated on the products' label. Analysis of Brand B, a tincture, showed that it contained almost half of the silymarin content found in Brand A capsules. Significant variations in the ratios of the flavanolignan constituents among products and seeds, as well as variation between product and product label were detected.
Development of lateral flow membranes for immunoassay separation

The lateral flow nitrocellulose membrane is one of the commonly used separation media for bacteria detection in drinking water treatment facilities. In order to enhance its performance, control of the membrane surface and cross-section morphology is primarily important. The challenge of this study is to combine various formulations and casting variables to obtain lateral flow nitrocellulose membranes with the desired morphologies. Through the dry-phase inversion method, the drying temperature was found to be an important parameter in synthesizing membranes as it affects pore structures. A high drying temperature causes agglomeration of the polymer matrix, and thus smaller pores were observed on the membrane surface. This further decreases the membrane lateral liquid migration rate, besides reducing the membrane binding ability for bacteria detection. Results show that by decreasing polymer concentration, membrane surface pores became apparently larger, thus creating a faster lateral migration speed of the.
A new synthetic use of nucleoside N1-oxides

The use of adenosine N/sup 1/-oxide derivatives to prevent intramolecular cyclization during nucleophilic displacement reactions on the sugar moiety is described. This new synthetic use of N/sup 1/-oxides is illustrated by the synthesis of 5'-O-(p-toluenesulfonyl)-2',3'-O-isopropylideneadenosine N/sup 1/-oxide (6) and subsequent displacement of the 5' substituent with iodide or azide under conditions which lead exclusively to N/sup 3/. -->. 5' intramolecular cyclization in the absence of the N/sup 1/-oxide. Similarly, reaction of 2',3'-O-isopropylideneadenosine N/sup 1/-oxide with methyltriphenoxyphosphonium iodide produces 5'-iodo-5'-deoxy-2',3'-O-isopropylideneadenosine N/sup 1/-oxide (7) with no observable cyclization. In addition, 2',3'-anhydroadenosine N/sup 1/-oxide (17) is shown to be stable under conditions that lead to complete N/sup 3/. -->. 3' intramolecular cyclization in the upprotected 2',3'-anhydroadenosine (14). Reduction of the N/sup 1/-oxide to produce the parent nucleoside is readily achieved by using hexachlorodisilane or by hydrogenating over Raney nickel. The mechanistical rationale and implications for additional nucleoside transformations are discussed. 2 tables, 1 figure.
The Debye-Hückel theory for hydrated ions. I, Osmotic and activity coefficients of binary aqueous solutions of some 1 :1 electrolytes at 25°C

A thermodynamic model of stepwise hydration of ions in aqueous solutions has been developed. It is applied to the activity and osmotic coefficients of the alkali halogenides at 25°C. The hydration at infinite dilution can be decomposed into ion specific contributions. Together with a distance of closest approach in the Debye-Huckel term it is possible to describe the activity and osmotic coefficients within the experimental error limits up to 1 molal solutions.
Effect of 2-Propanol Concentration in Electrolyte Solution on Polypyrrole Actuator Performance

Organic soft linear actuators made of conducting polymers such as polypyrrole (PPy) films are of special interest for application in microelectromechanical systems (MEMS) because they generate large electrochemomechanical stress and strain. In this work, a PPy actuator was fabricated by galvanostatic electropolymerization. The electrochemical deformation behaviors of the PPy actuator were investigated in aqueous solutions of an electrolyte, lithium bis(trifluoromethanesulphonyl)imide (LiTFSI), containing different concentrations of 2-propanol. Marked improvement of the electrochemical strain from 3 to 12% was achieved when the actuator was driven by a potential between -1 and 1 V in the LiTFSI electrolyte containing 20 to 40% of 2-propanol under a load stress of 0.3 MPa. Possible mechanisms for these behaviors were discussed.
FEMTOSECOND DYNAMICS OF SOLVATION : MICROSCOPIC FRICTION AND COHERENT MOTION IN DENSE FLUIDS

In this paper, we present detailed experimental and theoretical studies of the femtosecond dynamics of microscopic friction. The real-time rotational motion of a well-defined system of diatomic solute in monatomic solvent has been studied for two solvents ranging from gas to liquid densities. Both coherent inertial and diffusive limits of the motion and all stages in the transition between these two regimes are observed in detail. The transient anisotropies over the entire range of experimental densities and solvents are well-represented by the J-coherence bimolecular collision model presented here. This stochastic hard-sphere collision model explicitly relates the physical properties of the solvent to the anisotropy and the coefficient of rotational friction, permitting calculation of the transient anisotropy from the Enskog hard-sphere collision frequency. Friction coefficients obtained from J-coherence analysis of experimental anisotropies were compared with those from Gordon J-diffusion, and Langevin−.
Quantitative applications of matrix‐assisted laser desorption/ionization with time‐of‐flight mass spectrometry: Determination of copolymer composition in bacterial copolyesters

Poly(β-hydroxybutyrate-co-β-hydroxyvalerate) of microbial origin has been analyzed by matrix-assisted laser desorption/ionization (MALDI) in a time-of-flight mass spectrometer, after partial methanolysis, using two different instruments, Our results show that the mass spectral intensities recorded in the MALDI mode correlate with previously reported fast-atom bombardment and direct chemical ionization data. MALDI compares favourably with these other two techniques in that it is more suitable to the analysis of complex mixtures and of higher molecular masses.
Low swelling capacity of highly stretched polystyrene brushes

We report the unusually low swelling capacity of highly stretched polystyrene chains grown on a silicon surface using “living” free radical polymerization. The control over the lateral density leads to brushes with a very high grafting density (up to >1.0 chain/nm2). Neutron reflectivity measurements have evidenced two specific features of such brushes: (i) the controlled nature of the surface polymerization through a very homogeneous growth of homopolymer and copolymer chains; (ii) the highest volume fraction in good solvent Φ(z=0) = 0.85 ever seen due to the highly stretched configuration of the dry chains, hindering a complete swelling of the layers and suggesting a significant deviation from predicted scaling laws.
The use of molecular beam epitaxy for the synthesis of high purity III–V nanowires

The synthesis methods and properties of catalyst-free III–V nanowires with molecular beam epitaxy (MBE) are reviewed. The two main techniques are selective-area epitaxy (SAE) and gallium-assisted synthesis. The excellent structure and ultra-high purity characteristics of the grown nanowires are presented by Raman and photoluminescence spectroscopy.
Bulk and surface phases of iron oxides in an oxygen and water atmosphere at low pressure

Thermodynamic stability ranges of different iron oxides were calculated as a function of the ambient oxygen or water gas phase pressure (p⩽1 bar) and temperature by use of the computer program EquiTherm. The phase diagram for Fe–H2O is almost completely determined by the O2 pressure due to the H2O dissociation equilibrium. The formation of epitaxially grown iron oxide films on platinum and ruthenium substrates agrees very well with the calculated phase diagrams. Thin films exhibit the advantage over single crystals that bulk diffusion has only limited influence on the establishment of equilibrium phases. Near the phase boundary Fe3O4–Fe2O3, surface structures are observed consisting of biphase ordered domains of FeO(111) on both oxides. They are formed due to kinetic effects in the course of the oxidation to hematite or reduction to magnetite, respectively. Annealing a Fe3O4(111) film in 5 × 10−5 mbar oxygen at 920–1000 K results in a new γ-Fe2O3(111)-like intermediate surface phase during the oxidation to α-Fe2O3(0001). A model is suggested for the growth of iron oxides and for redox processes involving iron oxides. The formation of several equilibrium surface phases is discussed.
Measurement of γ‐dose rates by n‐ and p‐type semiconductor detectors

n-Si detectors prepared of n-type silicon, as described in the literature, were used initially for the measurement of dose rates of a high activity 60Co radiation source. It was stated that the radiation induced a rapid “ageing” in an n-type detector leading to the decrease of sensitivity. On the basis of calculations of the photocurrent of semiconductor photovoltaic cells, a more radiation resistant detector is prepared using p-type silicon. Its sensitivity remained constant within ±10% up to a dose of 30 MR. This is sufficient for practical purposes. The photocurrent of the p-Si detector is linear in the range of dose rate between 50 and 107 R/h, using a recorder with a resistance of RT ≦ 1 kω. The directional dependence of the response is within ±20%, the temperature coefficient is 0.4% deg−1 between 20 and 80 °C. n-Si-Detektoren aus n-leitendem Silizium, wie sie in der Literatur beschrieben sind, wurden ursprunglich fur die Messung der Dosisraten einer hochaktiven 60Co-Strahlungs-quelle benutzt. Es wurde festgestellt, das die Strahlung eine rapide „Alterung” in einem n-leitenden Detektor hervorruft, die zu einem Abfall der Empfindlichkeit fuhrt. Auf der Grundlage von Berechnungen des Photostroms von Halbleiter-Photozellen wird ein strahllungsfesterer Detektor aus p-leitendem Silizium prapariert. Seine Empfindlichkeit bleibt innerhalb ± 10% bis zu Dosen von 30 MR konstant, was fur praktische Zwecke ausreichend ist. Der Photostrom des p-Si-Detektors ist im Dosisratenbereich von 50 bis 107 R/h linear bei Benutzung eines Schreibers mit einem Widerstand von RT≦ 1 kω. Die Richtungsabhangigkeit der Empfindlichkeit liegt innerhalb ±20%, der Temperaturkoeffizient betragt 0,4% grd−1 zwischen 20 und 80 °C.
Degradation kinetics of vulcanized ethylene–propylene–diene terpolymer residues

In this study, ethylene–propylene–diene terpolymer residues (EPDM-r) from the automotive industry were analyzed by thermogravimetric analysis (TGA) for determination of the activation energy (Ea) of decomposition by the Flynn-Wall-Ozawa (FWO) method. The degradation mechanism was determined by the method of Criado et al. Analysis of the nonvulcanized EPDM gum (EPDM-g) and paraffinic oil used in the composition of the compound was also carried out. The Ea values for the decomposition of the EPDM-g and paraffinic oil remained constant with the conversion, but for the EPDM-r decomposition, they changed due to the initial oil elimination followed by decomposition of the EPDM fraction. It was observed that removal of the paraffinic oil occurred less easily in the tridimensional vulcanized network, and there were differences in the elimination mechanism. The EPDM degradation mechanism was also affected by vulcanization and the fillers present in the compound. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
On-chip real-time nucleic acid sequence-based amplification for RNA detection and amplification

Development of integrated systems for nucleic acid analyses is mainly driven by the requirement for fast and simple clinical and environmental diagnostics. The need for affordable and effective point-of-care diagnosis has inspired an entire field of biotechnology in micro and nano-fluidics. We are developing a microfluidic system that has individual sub-systems for performing cell concentration and lysis, RNA extraction/purification and real-time RNA detection. The system is being developed to analyse the rbcL gene of phytoplankton Karenia brevis, a species responsible for harmful algal blooms. This integrated system will perform sub-cellular analysis of RNA using nucleic acid sequence-based amplification and would be used in large scale biochemical analysis and experimentation. The device could potentially be used for the detection of any species with a known target nucleic acid sequence for in situ environmental monitoring, forensics or clinical diagnostics.
Fluoride Adsorption Properties of CeO2 Powders and Al Foam Loaded CeO2

Cerium oxide powder and aluminum foam loaded cerium oxide were prepared by hydrothermal method using cerium nitrate hexahydrate and dimethyl oxalate (DMO) as raw material. Cerium oxide precursors and cerium oxide particles were characterized by field emission scanning electron microscopy (FESEM). Aluminum foam loaded cerium oxide was characterized by environment scanning electron microscopy (ESEM). On the basis of calculation and fitting of the experimental data, effect of the particle size on the adsorption rate, desorption rate and concentration of surface active sites of the powder and composite absorbents were studied. Results show that the removal of fluoride ions can be realized by exchange adsorption of oxhydryl on the cerium oxide particles surface and the fluoride ions in the solution.
Matrix-induced nanoparticle interactions in a polymer melt: A molecular dynamics simulation study

A molecular dynamics simulation study of the influence of a polymer melt matrix consisting of bead-necklace polymers on the effective interaction between two spherical nanoparticles was performed. The potential of mean force (POMF) between the two nanoparticles as well as entropy and energy contributions to the POMF was determined as a function of nanoparticle separation. The role of energy on the POMF was investigated by varying the strength of the polymer–nanoparticle interaction and comparing structure and POMF with those obtained for an athermal model. All features of the POMF as a function of nanoparticle separation were found to be strongly correlated with the polymer matrix density, the structure of the polymer at the nanoparticle interface, and the structure of the polymer in the interparticle region. The POMF was not found to correlate with polymer chain dimensions (e.g., radius of gyration) in contrast to colloidal suspensions in dilute and semidilute solutions. Both energy and entropy effects w.