Miracle-dz/UniFAR-FTUs huggingface dataset:
Synthesis and Growth of ZnO Nanoparticles

ZnO nanoparticles in the size range from 2 to 7 nm were prepared by addition of LiOH to an ethanolic zinc acetate solution. This method [Spanhel, L. ; Anderson, M. A. J. Am. Chem. Soc. 1991, 113, 2826] was modified and extended at several points. The synthesis of very small ZnO nuclei was simplified. It was found that aging of particles was governed by temperature, the water content, and the presence of reaction products. Water and acetate induced considerably accelerated particle growth. Growth could almost be stopped by removal of these species (“washing”). Washing consisted of repeated precipitation of ZnO by addition of alkanes such as heptane, removal of the supernatant, and redispersion in ethanol. The aging characteristics are interpreted in terms of the concentration of dissolved ZnII species and reactions well-known in sol−gel chemistry. These findings present a better-defined and more versatile procedure for production of clean ZnO sols of readily adjustable particle size. Such sols are of partic.
Discrimination of sibutramine and its analogues based on surface-enhanced Raman spectroscopy and chemometrics: toward the rapid detection of synthetic anorexic drugs in natural slimming products

Nowadays there is growing concern about the adulteration of synthetic anorexics in natural slimming products (NSP) due to the increasing use of weight-reducing aids. Here, we report surface-enhanced Raman spectroscopy (SERS) coupled with chemometrics for rapid discrimination and detection of sibutramine (SIB) and its analogues (mono-desmethylsibutramine, MDS; di-desmethylsibutramine, DDS) in konjac pressed candy (KPC), which is a NSP used in the treatment of obesity. It has been demonstrated that the two characteristic peaks at 1060 cm−1 (in SERS spectrum of SIB) and 1407 cm−1 (in SERS spectrum of MDS) were used to discriminate between SIB, MDS and DDS. Moreover, the two spectra for KPC with MDS and KPC with DDS only exhibited some slight differences. After the second derivative transformation, the differences were much more clear, especially for the peak at 1407 cm−1 in the SERS spectrum of KPC with MDS. Meanwhile, partial least-squares regression was used for quantitative analysis of the samples. The limit of detection for SIB, MDS and DDS was 5.00 × 10−8 M, 5.00 × 10−7 M and 1.00 × 10−6 M, respectively. Compared with previously reported studies, the method is simple (no pretreatment), less time-consuming and inexpensive, and can be applied to rapidly screen SIB and its analogues in NSP.
Effects of Au fraction on the morphology and stability of Au–Ag–Cu trimetallic particles prepared using a polyol method

AuAgCu alloy and phase-separated AuAgCu/Cu nanoparticles were prepared by reducing mixtures of Au(OAc)3, AgNO3, and Cu(OAc)2·H2O in ethylene glycol (EG) in the presence of poly(vinylpyrrolidone) (PVP) at 175 °C. At Au(OAc)3:AgNO3:Cu(OAc)2·H2O molar ratios of 1:1:1, short string and peanut types of AuAgCu alloy nanoparticles were formed after 2.5–40 min heating. For Au(OAc)3:AgNO3:Cu(OAc)2·H2O molar ratios of 0.5:1:1 and 0.1:1:1, peanut-type or spherical AuAgCu alloy core Cu shell nanoparticles denoted as AuAgCu@Cu were produced after 5 min heating. They changed to a mixture of AuAgCu alloy and phase-separated AuAgCu/Cu nanoparticles after 17.5–37 min heating. The growth mechanisms of AuAgCu, AuAgCu@Cu, and AuAgCu/Cu particles were examined using TEM energy dispersed X-ray spectroscopic (EDS), XRD, and ultraviolet (UV)-visible (Vis)-near infrared (NIR) extinction spectral data. The time dependence of UV-Vis-NIR spectral data indicated that AuAgCu and AuAgCu/Cu nanoparticles retain high stability including anti-oxidation properties for a long time after preparation.
Mode and Place of Origin of Carbonaceous Aerosols Transported From East Asia to Cape Hedo, Okinawa, Japan

This study investigated the source categories and emission areas of carbonaceous aerosols transported from East Asia to the East China Sea. Mass concentrations of heavy metals, ionic components, organic carbon, and elemental carbon (EC) were measured at the Cape Hedo Atmosphere and Aerosol Monitoring Station in Okinawa, Japan, throughout 2010. The relative influences of different categories of aerosols were determined by positive matrix factorization, and the source regions of each emissions category were evaluated by using the total potential source contribution function. Five source categories were identified: dust, sea salt and nitrate, secondary species, coal combustion, and oil combustion. The results showed that the major source of aerosols in North China is coal combustion, whereas the major source in South China, Japan, and Korea is oil combustion. The relative contributions of the five sources to EC concentrations at Cape Hedo were dust 7.0%, sea salt and nitrate 19.1%, secondary species 28.5%, oil combustion 12.8%, and coal combustion 32.6%. In particular, wintertime coal combustion in residential areas of North China contributed significantly to EC in 2010. The results also indicate that the contribution of coal combustion in source areas was higher in winter (52%), whereas the contribution of oil combustion was higher in spring (33%).
Effects of elastic scattering on energy spectra of emitted and backscattered electrons

The problem of elastic and inelastic scattering of Auger electrons, photoelectrons and backscattered electrons is investigated. The path length distribution functions for emitted and backscattered electrons are calculated analytically in different approximations for elastic scattering. The calculations are carried out on the basis of an invariant-embedding approach. A procedure of background subtraction in AES/XPS in the presence of elastic scattering and a procedure of reflection electron energy-loss spectra processing are also discussed.
Treatment of Fermi resonance effects on transition moments in vibrational perturbation theory

An algebraic expression for the vibrational transition moment of fundamental transitions within the context of second-order vibrational perturbation theory (VPT2) has been modified to account for cases in which the fundamental interacts through a Fermi resonance with close-lying two-quantum levels. This procedure is applied to the formaldehyde molecule, and it is shown that explicit treatment of the 51 ≈ 2161 ≈ 3161 resonance is necessary to give intensities of the ν5 transitions that agree qualitatively with that seen experimentally. In addition, use of the Almlöf–Taylor atomic natural orbital basis sets results in an extremely close correspondence between predicted and observed level positions; the largest difference found for the 23 one- and two-quantum transitions for which experimental assignments have been made is 15 cm−1. This is a remarkable result, especially when one considers that seven of these levels are involved in relatively strong resonances.
Comparison of different sample preparation procedures for multiclass determination of selected veterinary drug, coccidiostat and insecticide residues in eggs by liquid chromatography-tandem mass spectrometry

This paper presents the evaluation of extraction techniques and sample clean-up procedure for the simultaneous determination of residues of veterinary drugs (sulphonamides, fluoroquinolones, tetracyclines, macrolides, β-lactams, nitroimidazoles, benzimidazoles, amphenicols, lincosamides and pleuromutilins), coccidiostats and insecticides in fresh egg samples. The study utilises the liquid chromatography-tandem mass spectrometry technique to obtain suitable analytical parameters for the screening and confirmatory method. The results of egg samples analysed by 8 different sample preparation schemes were compared by using the mean recoveries. The recoveries of analytes showed that both SPE and modified QuEChERS have not been sufficient for the extraction of all the analytes in the expected range of 70–120%. Additional cleaning with dispersive sorbents prolonged the time taken by the sample preparation steps and provided slightly different final extract clarity results. The most demanding analytes to isolate from the samples were coccidiostats, while sulphonamides were the group of analytes for which all the proposed sample clean-up procedures were suitable. As the chosen method, extraction with 0.1% formic acid in acetonitrile–water (8 : 2) and clean-up with HybridSPE can be applied as a sample preparation step for the screening and confirmatory method in official laboratories.
Synthesis of poly(glycidol)‐block‐poly(N‐isopropylacrylamide) copolymers using new hydrophilic poly(glycidol) macroinitiator

New, water soluble poly(glycidol) (PGI) macroinitiators for atom transfer radical polymerization (ATRP) were synthesized. This new class of macroinitiators were prepared in a three-step process. First, series of well-defined co-hydroxyl functional poly(glycidol acetal)s with different molecular weights was synthesized via anionic polymerization followed by quantitative termination of anionically growing active sites. End capping was achieved by treatment of living chain ends with water. The living nature of the system and termination reaction is discussed. In the second stage, monofunctional poly(glycidol acetal)s were functionalized by esterification with 2-chloropropionyl chloride. Finally, selective deprotection (hydrolysis) of acetal protective groups was performed. As simultaneous partial cleavage of ester bond of attached ATRP moieties was unavoidable, the final functionality of macroinitiator calculated from 1 H NMR varied in the range 85-95%. The obtained (2-chloropropionyl) poly(glycidol) macroinitiator with DP = 55 and 90% functionality was successfully used in ATRP polymerization of N-isopropylacrylamide (NIPAAm) at room temperature in the DMF/water mixture. Linear block copolymers with relatively narrow molecular weight distribution and controlled composition were obtained and characterized with 1 H NMR and SEC-MALLS measurements.
Dielectric Anomaly in Mg Doped ZnO Thin Film Deposited by Sol–Gel Method

Magnesium doped ZnO Zn0.75Mg0. 25O polycrystalline thin film was deposited on p-type Si by sol–gel method, and the same was annealed at 1000°C in oxygen rich environment. The magnesium doping in lattice structure of zinc oxide was examined by X-ray diffraction measurements. The dielectric phase transition observed at 378 K indicated the existence of ferroelectric properties in the deposited film. The ferroelectricity in the deposited film was confirmed by the polarization and electric field hysteresis curve. Maximum values of the spontaneous polarization and coercive field were found to be 0.29 C/cm2 and 18 kV/cm, respectively. The clockwise rotation in capacitance and voltage hysteresis loop of the deposited film on p-type Si indicated that the charge compensation on the Si surface was induced by the ferroelectric polarization. The grain size and microstructure were analyzed by atomic force microscopy. © 2010 The Electrochemical Society. DOI: 10.1149/1.3511788 All rights reserved.
Reengineering CelA2 cellulase for hydrolysis in aqueous solutions of deep eutectic solvents and concentrated seawater

Cellulases are promising catalysts for the depolymerization of cellulose under mild conditions. Reengineered cellulases are required to match application demands in biorefineries and to avoid cost-intensive downstream processing. This manuscript provides a novel fluorescence-based high throughput screening method for directed evolution of cellulases, based on 4-methylumbelliferyl-β-D-cellobioside (4-MUC). The 4-MUC high throughput screening system was successfully employed to identify CelA2 variants with enhanced stability and activity in mixtures of water with deep eutectic solvents like choline chloride : glycerol (ChCl : Gly), and seawater. The cellulase variant 4D1 (L21P; L184Q; H288R; K299I; D330G; N442D) was isolated and showed, compared to wild type, an increase in specific activity in 30% (v/v) ChCl : Gly (7.5-fold; 0.4 to 3.0 U mg−1) and in concentrated seawater (1.6-fold; 5.5 to 9.3 U mg−1). In addition, the residual activity of 4D1 in the presence of 3-fold concentrated seawater is unaffected whereas CelA2 wild type loses >50% of its activity. Furthermore, the position H288 was identified as a key position for activity and resistance in 4D1.
Search for the Standard Model Higgs Boson Produced in Association with a Vector Boson and Decaying to Bottom Quarks at the CMS Detector

A search for the Standard Model Higgs boson produced in association with a W or Z boson and decaying to bottom quarks is presented. A sample of approximately 24 fb−1 of data recorded by the CMS experiment at the Large Hadron Collider, operating at center-of-mass energies of 7 TeV and 8 TeV in 2011 and 2012, respectively, is used to search for events consistent with the signature of two b jets recoiling with high momentum from a W(`ν), W(τν), Z(``), or Z(νν) decay, where ` refers to either an electron or a muon. One-prong hadronic decays of the tau particle are selected for in the case of W(τν). Observed signal significance and 95% confidence level upper limits on the production cross section times H→ bb̄ branching fraction, relative to the Standard Model prediction, are presented for the 110-135 GeV Higgs mass range.
Enhanced performance of flexible dye-sensitized solar cells: electrodeposition of Mg(OH)(2) on a nanocrystalline TiO2 electrode

Nanocrystalline TiO2 photoanodes were prepared on a conductive indium–tin oxide coated polyethylene naphthalate (ITO-PEN) plastic substrate by the doctor-blade method to fabricate flexible dye-sensitized solar cells (DSCs). The surface of the photoanode was coated with Mg(OH)2 by electrodeposition and the deposition time was systematically varied (2, 4, 6, 8, and 10 min). Electrodeposited Mg(OH)2 was confirmed by IR and energy dispersive X-ray (EDX) analysis. The surface morphology was studied by scanning electron microscopy. The internal surface area of TiO2 was studied against the deposition time by taking into account the projected surface area of the photoelectrode and it shows that the internal surface area of the photoelectrode was reduced as the Mg(OH)2 deposition time increased. The performance of flexible DSCs on various deposition times of Mg(OH)2 was evaluated on the basis of their photocurrent density–voltage characteristics. Among the deposition times, 2 min showed the best performance in Voc.
Fourier transform carbon-13 relaxation and self-diffusion studies of microemulsions

Multi-field 13C n.m. r. relaxation (spin–lattice relaxation and nuclear Overhauser enhancement) and multi-component Fourier-transform n.m. r. self-diffusion measurements have been applied to provide information on different aspects of the dynamic structure of microemulsions. Studies were performed over extensive concentration regions for four-component systems composed of sodium p-octylbenzene sulphonate, butan-l-ol, water and n-decane or toluene while limited investigations were made for other systems. The 13C relaxation data were analysed on the basis of a two-step model of relaxation to provide information on short- and long-range molecular dynamics and on the degree of order of the alkyl chains with respect to hydrophobic–hydrophilic interfaces. The local motion of the alkyl chains is generally about as rapid (10–11 s) as that of liquid hydrocarbons. The effect of the organization in the system and the creation of hydrophobic–hydrophilic interfaces is a slight anisotropy in the molecular motion. This anisotropy is similar in magnitude to that of liquid-crystalline phases, but for the microemulsions the lifetime of the anisotropy is very short, one or two nanoseconds. According to the self-diffusion results, a closed water droplet structural model may apply for alcohols with longer alkyl chains. For the above-mentioned systems with butanol as cosurfactant the self-diffusion coefficients of both water and hydrocarbon are quite high and inconsistent with structurally segregated domains, unless these are very short-lived.
The Influence of Various Air Exchange Rates on Airborne Particles and Microorganisms in Conventionally Ventilated Operating Rooms

Abstract Concentrations of airborne particles and microorganisms were assessed as a function of the air exchange rate in two operating theatres equipped with conventional air ventilation systems. The measurements were made with and without human activity (surgery). Under conditions without human activity the effect of the air exchange rate on viable (=microorganisms) and non-viable airborne particles was measured. Under conditions with human activity an investigation was made to determine whether the air exchange rate has a significant influence on airborne particle and bacteria concentrations. In addition, the influence of the number of persons in the operating theatres and the various operating activities were calculated. Statistical differences were found for airborne particle and airborne bacteria concentrations in supply and room air with and without human activity. From the point of view of hygiene, these differences must be considered irrelevant because of the slight margin (less than one logarithmic step) between the values. A comparison of all air exchange rates clearly shows that the number of personnel present in the operating theatre exerts the strongest influence on airborne particle concentration variance in room air. As regards airborne bacteria concentrations in room air, explanation of variance by the parameters air exchange rate, number of persons and operating activity is negligible. Summarizing the low (7.5 and 10/h) and high (15 and 20/h) air exchange rates did not increase the explanation of variance for airborne particle and bacteria concentrations although the differences were significant.
Compatibility characterization of poly(lactic acid)/poly(propylene carbonate) blends

The compatibility of poly(lactic acid) (PLA)/poly(propylene carbonate) (PPC) blends was investigated with Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. The PLA/PPC blends were prepared over the whole composition range. FTIR spectroscopy revealed that there were several specific interactions between the chains of PLA and PPC: the interaction between CH and OC and CO···OC or CO···OC dipole–dipole interactions. Moreover, PLA and PPC were compatible. DSC indicated that PLA and PPC were partially miscible but compatible to some extent because of the similar chemical natures of the blend components. TGA showed that the compatibility of PLA and PPC enhanced the thermal stability of PPC in the blends. As calculated by the Horowitz–Metzger equation, the activation energy for decomposition (Et) of PPC in PLA/PPC (70/30) was 200.6 kJ/mol, whereas Et of pure PPC was only 56.0 kJ/mol. A study of the mechanical properties versus the composition and the strain versus the stress illustrated that there was good compatibility between PLA and PPC, and the phase inversion of the PLA/PPC system occurred between 70 and 60 wt % PLA in the PLA/PPC blends. The Pukanszky model gave credit to very strong interfacial adhesion between PLA and PPC. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 94–101, 2006
Flavor Volatiles of Rice During Cooking Analyzed by Modified Headspace SPME/GC-MS

ABSTRACT The flavor volatiles in three Japanese rice cultivars, Nihonbare, Koshihikari, and Akitakomachi, during cooking were directly extracted by using a modified headspace solid-phase microextraction (SPME) method and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 46 components were identified, including aldehydes, ketones, alcohols, and heterocyclic compounds, as well as fatty acids and esters, phenolic compounds, hydrocarbons, etc. The amount of key odorant compounds increased with cooking, while the amount of low-boiling volatiles decreased. The similarities and differences of the three rice cultivars were determined through a comparison of their volatile components. Nihonbare was characterized by a higher amount of indole but an absence of the chemical class of fatty acid esters. In contrast, both Koshihikari and Akitakomachi had a higher amount of 4-vinylphenol and an abundance of those esters. Koshihikari and Akitakomachi were quite similar in regard to those flavor volatile.
Quantitative Comparison of Mixed Conducting SOFC Cathode Materials by Means of Thin Film Model Electrodes

Geometrically well-defined model electrodes have been employed to unambiguously elucidate the individual resistive and capacitive processes of various solid oxide fuel cell cathodes by means of impedance spectroscopy. The measurements were performed on dense, thin film-type microelectrodes of La 1-x Sr x Co 1-y Fe y O 3-δ and related perovskite-type materials prepared by pulsed laser deposition and photolithography. It was found that the substitution of the A-site cation La in La 1-x Sr x Co 1-y Fe y O 3-δ by Sm and especially by Ba leads to a strong enhancement of the surface exchange kinetics, whereas a variation of the Co/Fe ratio between 0 and 1 has only little effect on this quantity at temperatures around 750°C. Furthermore, it has been studied how the electrochemical activation effect, i.e., the strong reduction of the surface exchange resistance after application of a large dc bias, depends on composition.
Directional interactions in semiflexible single-chain polymer folding

Precise control over folded conformations of synthetic polymers is highly desirable in the development of functional nanomaterials for diverse applications. Introducing monomers capable of strong intramolecular hydrogen bonding is a promising route to achieve this control. In the present work we report the use of Wang–Landau Monte Carlo simulations of coarse-grained copolymers to explore the design parameters of these systems on their pathway to collapse. The highly directional nature of hydrogen-bonded supramolecular interactions is modelled by a directional non-bonded potential while a harmonic bending potential is used to take into account the flexibility of the polymer chain, thus making it possible to look at the interplay of both factors. The introduction of directional interactions in the copolymer chain leads to a sharper coil-globule collapse when compared to homopolymers composed of isotropic interacting beads only. Simultaneously, some of the stiffness-dependent structural properties become exacerbated when directional beads are present. Finally, from the heat capacity profiles for the different chain stiffness values we are able to distinguish the prevalence of the collapse of the backbone for highly flexible chains, while as chain stiffness increases folding of the co-polymer due to the directional interactions becomes the dominant feature.
Molecular dynamics simulation of an amorphous polymer under tension. 1. Phenomenology

Molecular dynamics computer simulation has been used to study the properties of a linear polymer model resembling polyethylene over a wide range of temperatures. By applying uniaxial tension to the samples, elasticity, yield, and plastic flow at low temperatures and viscoelasticity at high temperatures are characterized. Qualitative comparisons show that there are strong similarities between these short time (∼ 1 ns) simulations and laboratory measurements obtained on time scales orders of magnitude longer