Miracle-dz/UniFAR-FTUs huggingface dataset:
Composition and surface structure of the (0001) face of .alpha.-alumina by low-energy electron diffraction

· ~ The (0001) crystal face of ci-alumina undergoes. a change of surface structure upon heat treatment in vacuum above 1250°C. This order-order phase transformation [(Al(OOOl) - (1 x 1) _. ,_rotated ( ~31 x ~ 31)] is accompanied by a change in the chemical composition of the surface, i. e. by the loss of oxygen. The structural change is reversible and either surface structure can be obtained alternately by heat treatment of the samples in oxygen (>lo-4 torr) or in the presence of excess aluminum on the surface. The large unit cell which characterizes the high-temperature oxygen-deficient surface structure is indicative of a marked mismatch between the surface layer and the underlying (0001) crystal orientation. Evidence is presented to s,how that the aluminum cation in the high temperature surface structure is in a reduced valence state and that the structure in composed of a cubic overlayer on the hexagonal ~~alumina substrate. It appears that compounds with unusual oxidation states which would not be stable in the solid state may be stabilized in the sur'face environment.
An integrated thermal biosensor array for multianalyte determination demonstrated with glucose, urea and penicillin

Abstract An integrated thermal biosensor array was designed and fabricated for the simultaneous determination of glucose, urea and penicillin. The sensor contains six thin-film thermistors which were fabricated on quartz chip by micromachining and semiconductor technology. This sensor allows the determination of three different analytes nearly simultaneously by serially partitioning a single microchannel into three distinct detection regions. Each of the regions contained one immobilized enzyme matrix and a pair of thermistors for differential measurement of temperature changes in association with the enzyme reactions. Using this device, glucose, urea and penicillin-G at different concentrations were determined in the mixed samples. Linear ranges of 1 to at least 25 mM urea and penicillin, and up to 20 mM glucose were obtained using a sample volume of 20 μL.
Using DL_POLY to study the sensitivity of liquid structure to potential parameters

Two case studies are presented showing the local structure in liquids and how it responds to changes in the intermolecular potential. The idea is to use realistic and unrealistic potentials in order to determine the sensitivity of local liquid structure to potential parameters. The first case study concerns two families of modified water models. In the “hybrid” family, the hydrogen bond strength is reduced, but the geometry kept constant; in the second family, the molecular geometry is changed by reducing the bond angle, keeping a constant molecular dipole moment. The local structure is measured by radial distribution functions, three-dimensional probability distribution functions and three-body angular correlations. The second case study concerns the ionic liquid dimethylimidazolium chloride ([C1mim]Cl). The effect of reducing the hydrogen bonding potential of the cations while maintaining their charge is examined.
Step-addition Method for Enhancing the Yield of Gold Nanoparticles in Block Copolymer Solution

Triblock copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) has been used to synthesize gold nanoparticles from hydrogen tetrachloroaureate (III) hydrate (HAuCl4·3H2O) salt in aqueous solution at room temperature. Measurements were performed using the triblock copolymer Pluronic P85 (EO26PO39EO26) at a fixed concentration (1 wt%) mixed with varying HAuCl4·3H2O concentration in the range of 0.001 to 0.1 wt%. The surface plasmon resonance (SPR) band in UV-visible absorption spectra confirmed the formation of the gold nanoparticles. The maximum yield of the nanoparticles was found at 0.005 wt% of the salt solution. Small-angle neutron scattering (SANS) does not show any significant change in the scattering profile in these suspensions of the nanoparticles. A similar behavior was also observed in dynamic light scattering (DLS) experiments where autocorrelation function was found to be independent of the salt concentration. This can be understood since a high-block copolymer-to-gold ion ratio (r ∼ 22) is required in the reduction reaction to produce gold particles. As a result, a very small fraction of the block copolymers were associated with the gold nanoparticles, and hence lead to a very low yield. Both SANS and DLS basically see the micelles of most of these block copolymers, which are not associated with nanoparticles. Based on this explanation, a step-addition method was used to enhance the yield of gold nanoparticles by manifold, where the gold salt is added in small steps to maintain higher value of r (>22), and therefore continuous formation of nanoparticles.
Utilization of Nigella sativa L. Essential Oil to Improve the Nutritive Quality and Thymoquinone Contents of Baked Products

5 Abstract: Nigella sativa L. (Black cumin) is important medicinal plant and hold religious importance too. The core objective of present research study was to utilize Black Cumin Essential Oil (BCEO) as functiona l ingredients to improve the nutritive quality and thymoquinone contents of cereal-based bakery products. The results indicated that addition of essential oil influenced the physical and chemical characteristics of cookies non-significantly. Thymoquinone contents of cookies were highest in cookies containing 0.3% BCEO (7.25±0.482 mg/100 g) as compared to control (0.0 mg/100 g). Additionally, BCEO improved the oxidative stability of the cookies as indicated from decreased Peroxide Value (POV) and TBA value. Moreover, progressive increase in essential oil in cookies formulation didn't confer any deleterious impact on overall acceptability and judged by the trained taste panel during sensory appraisal. Present research investigation brightened the prospects of using black cumin essential oil in different food products that may produce healthy impact on end consumers.
Simultaneous Extraction and Derivatization of Volatile Organic Acids in Flue-Cured Tobacco with Headspace Solid-Phase Microextraction Followed by GC-MS

Simultaneous extraction and derivatization followed by head-space solid-phase microextraction (HS-SPME) coupled with gas chromatography/mass spectrometry (GC-MS) was employed to determine volatile organic acids (VOAs) in flue-cured tobacco samples. Several experimental parameters, such as the type of SPME fibers, sampling temperature, pre-extraction and derivatization equilibration time, and anhydrous sodium sulfate amount, were optimized to improve sampling efficiency. Validation was carried out in terms of limits of detection (LOD), precision, recovery, and linearity. The results indicated that the optimized technique was easy, highly efficient, and sensitive. Finally, the performance of the proposed method was tested for the extraction and determination of the VOAs in flue-cured tobacco and satisfactory results were achieved.
A mixing controlled direct chemistry (MCDC) model for diesel engine combustion modelling using large eddy simulation

A mixing controlled direct chemistry (MCDC) combustion model with sub-grid scale (SGS) mixing effects and chemical kinetics has been evaluated for Large Eddy Simulation (LES) of diesel engine combustion. The mixing effect is modelled by a mixing timescale based on mixture fraction variance and sub-grid scalar dissipation rate. The SGS scalar dissipation rate is modelled using a similarity term and a scaling factor from the analysis of Direct Numerical Simulation (DNS) data. The chemical reaction progress is estimated from a kinetic timescale based on local internal energy change rate and equilibrium state internal energy. An optical research engine operating at conventional operating conditions and Low Temperature Combustion (LTC) conditions was used for evaluation of the combustion model. From the simulation results, the effect of SGS scalar mixing is evaluated at different stages of combustion. In the context of LES, the new approach provides improved engine modelling results compared to the Direct Chemistry Solver (DCS) combustion model.
Structure and conformation of the anticodon nucleoside 5-methoxyuridine in the solid state and in solution

The three-dimensional structure of 5-methoxyuridine (mo5U) was determined with much higher precision than in a previous study (Hillen etal. J. Carbohydr. Nucleosides Nucleotides, 5, 23 (1978)). The crystals belong to the monoclinic space group P21 and the cell dimensions are a = 8.916(2), b = 14.372(2), c = 4.714(1) A, β = 97.44(2)°. Intensity data were measured with a diffractometer and the structure was solved by direct methods. Least-squares refinement, which included all hydrogen atoms, converged at R = 0.031. The conformation about the glycosyl bond is anti (χCN = 23.1°), the pucker of the ribose ring is C(3′)endo, and the conformation of the —CH2OH side chain is gauche+. A comparison of the bond lengths N(3)—C(4) and C(4)—O(4) with those in uridine does not support the conclusion of Hillen etal. about a shift to the enol tautomer in mo5U. However, there are other changes in the geometry of the pyrimidine ring due to substitution at C(5). A conformational analysis, based on 1H and 13C nmr data, shows.
Highly Cross-Linked Epoxy Resins: An Atomistic Molecular Dynamics Simulation Combined with a Mapping/Reverse Mapping Procedure

This paper presents a new computational method for simulating polymer network formation. There are four separate procedures involved in the methodology for this multiscale simulation: (i) mapping of the polymerizing monomers onto a coarse-grained model, (ii) cross-linking the monomers by applying Monte Carlo simulation to the coarse-grained model, (iii) reverse mapping of the coarse-grained model to a fully atomistic representation, and (iv) simulation of the atomistic model through standard molecular dynamics technique. Molecular dynamics simulations and experimental studies are carried out to check the algorithm on the basis of the determination of the physical properties of the cycloaliphatic epoxy resin which is prepared from 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate as resin monomers and 4-methylhexahydrophthalic anhydride as curing agents. Depending on the effective conversion and temperature, we determine the density, the glass transition temperature, and the thermal expansion coefficient of the cross-linked epoxy system. An increase in the degree of cross-linking is found to increase the glass transition temperature. Good agreement between computer simulation and experimental results is achieved for highly cross-linked networks, thereby showing that the simulation model is basically valid.
Synthesis of α- and β-lapachone derivatives from hetero diels-alder trapping of alkyl and aryl o-quinone methides

Foram sintetizados, em um unico pote reacional, alguns derivados da α- e β-lapachonas a partir de reacao de hetero Diels-Alder, em etanol aquoso, entre estirenos substituidos (como dienofilos) e o-quinonas metideos (o-QMs) metilenicas e arilicas geradas por condensacao de Knoevenagel da 2-hidroxi-1,4-naftoquinona com formaldeido e aldeidos aromaticos. Methylene and aryl o-quinone methides (o-QMs) generated by Knoevenagel condensation of 2-hydroxy-1,4-naphthoquinone with formaldehyde and arylaldehydes, undergo facile hetero Diels-Alder reaction with some substituted styrenes (as dienophiles) in aqueous ethanol media providing derivatives of α- and β-lapachone.
Measurement of Thermal Neutron Cross Section and Resonance Integral of the Reaction 135Cs(n, γ)136Cs

The thermal neutron (2,200 m/s neutron) capture cross section (σ0) and the resonance integral (I 0) of the reaction 135Cs(n, γ)136Cs were measured by means of an activation method to obtain fundamental data for research on the transmutation of nuclear waste. Targets of radioactive cesium, which include 135Cs and 137Cs as well as stable 133Cs, were irradiated with reactor neutrons within or without a Cd shield case. The Co/Al and Au/Al alloy wires as activation detectors were irradiated together with cesium samples to monitor the neutron flux and the fraction of the epithermal part (Westcott's index). A high purity Ge detector was used for the γ-ray measurements. The 137Cs nuclide was used as a tracer of 135Cs, since 135Cs decays through β-transition, but does not emit γ-rays. The ratio of the number of nuclei of 135Cs to that of 137Cs in the target was measured with a quadrupole mass spectrometer. This ratio and the ratio of activity of 136Cs to that of 137Cs in the irradiated target were used for deducti.
Detection of Attomole Quantitites of DNA Targets on Gold Microelectrodes by Electrocatalytic Nucleobase Oxidation

The electrochemical detection of nucleic acid targets at low concentrations has a number of applications in diagnostics and pharmaceutical research. Self-assembled monolayers of alkanethiol-derivatized oligonucleotides on gold electrodes provide a useful platform for such detectors, and the electrocatalytic oxidation of nucleobases included in the DNA targets is a particularly sensitive method of electrochemical detection. A strategy has been developed for combining these two aspects by substituting either 7,8-dihydro-8-oxoguanine (8G) or 5-aminouridine (5U) into DNA targets. Upon hybridization of targets containing these modified nucleobases, electrocatalytic signals at probe-modified gold electrodes are observed in the presence of Os(bpy)32+, which oxidizes both 8G and 5U upon oxidation to the Os(III) state. Self-assembled monolayers were prepared on both macro (1.6 mm) and micro (25 μm) gold electrodes using published procedures involving C6-terminated alkanethiol oligonucleotides and mercaptohexanol a.
Synthesis of star polymers using RAFT polymerization: What is possible?

Various pathways to generate star polymers using reversible addition? fragmentation transfer (RAFT) are discussed. Similar to other polymerization techniques, star polymers can be generated using arm-first and core-first approaches. Unique to the RAFT process is the subdivision of the core-first approach into the R-group and Z-group approaches, depending on the attachment of the RAFT agent to the multifunctional core. The mechanism of the R- and Z-group approaches are discussed in detail and it is shown that both techniques have to overcome difficulties arising from termination reactions. Termination reactions were found to broaden the molecular weight. However, these side reactions can be limited by careful design of the synthesis. Considerations include RAFT and radical concentration, number of arms, type of RAFT agent and monomer. Despite obvious challenges, the RAFT process is highly versatile, allowing the synthesis of novel polymer architectures such as poly(vinyl acetate) and poly(vinyl pyrrolidone) star polymers. © CSIRO 2006.
Polysorbate 20 prevents the precipitation of a monoclonal antibody during shear

Monoclonal antibodies (MAbs) are widely used as therapeutic proteins and they are frequently exposed to a high degree of stress during manufacturing or delivery. MAbs shear thin upon increasing shear rates. After undergoing multiple shear cycles, with a cone-and-plate rheometer, the solution viscosity of high concentration antibodies increases due to the formation of insoluble aggregates. These shear-induced insoluble aggregates do not form when polysorbate 20 is present in solution. We hypothesize that monoclonal antibodies form a thin protein layer at the air-water interface. MAbs at the interface expose their hydrophobic core to air leading to unfolding, multiple non-specific intermolecular interactions and, upon continuous high shear, precipitation. Surface tension analysis confirms that monoclonal antibodies are surface active and that polysorbate 20 can prevent their interaction with the air-water interface. In addition, we complement these findings with a viscometer that measures bulk viscosity without the influence of an air-liquid interfacial viscosity and find that the bulk viscosity increases slightly when Mab solutions contained polysorbate 20. These methods of analysis could be used when designing manufacturing systems in which a protein solution is subject to shear forces.
Comparative study between the different compartments of Opuntia ficus-indica L.

The study was performed on the three compartments (peels, juicy pulp and seeds) of the Opuntia ficusindica orange variety, collected in the area of Bejaia (Algeria). The analysis consisted in determining the proportion of various bioactive molecules in each part and in evaluating the antioxidant and antiradical activities of the ethanol extracts. Results are expressed on dry matter. The quantification of the antioxidants in the three parts of the fruit revealed significant differences at p≤0.05. Indeed, the peels presented higher yields in total phenolic compounds (1507.7mg EAG/100g) and flavonoids (18.7mg EQ/100g) followed by the juicy pulp (245.1 mg EAG/100g and 3.8 mg EQ/100g). The level of tannins was low in all samples and did not exceed 2mg EC/100g. Evaluation of antioxidant activity of the ethanol extracts, showed better reduction potential and the inhibitory effect of DPPH in the peels extract. OFI constitutes a good source of interesting value added compounds which are considerably higher in the peels part.
Sensing the fugacity of hydrophobic organic chemicals in aqueous systems

It is suggested that sensing the fugacity of hydrophobic chemicals in aqueous systems by measuring their concentrations in an equilibrated air headspace can provide valuable information about the nature and extent of interactions between the chemicals and dissolved and particulate phases present in the water. An experimental air-water closed system is described into which sorbing materials can be titrated and the fugacity response determined by continuous air circulation with periodic gas sampling and GC analysis.
Game design workshop : a playcentric approach to creating innovative games

The Role of the Game Designer. The Structure of Games. Working with Formal Elements. Working with Dramatic Elements. Working with System Dynamics. Conceptualization. Prototyping. Digital Prototyping. Playtesting. Functionality, Completeness, and Balance. Fun and Accessibility. Team Structures. Stages of Development. The Design Document. Understanding the Game Industry. Selling Yourself and Your Ideas to the Game Industry.
DIFFUSION-CONVECTION PROCESS IN A BRANCHING FIN

The diffusion-convection transport process in a branching fin with a power-law type transfer coefficient (h = a0m) was investigated theoretically. The governing equations were formulated and the solution was obtained analytically. For systems with m> - 1, the steady-state distribution for the state variable 0 was unique and stable. When the exponent becomes less than - 1, nevertheless, bistability occurs if the steady-state solution exists. Linear stability analysis shows that the lower branch solution on the fin efficiency/effectiveness versus branching number plot was stable, whereas the upper solution was unstable to small perturbations.
CoP as an Acid-Stable Active Electrocatalyst for the Hydrogen-Evolution Reaction: Electrochemical Synthesis, Interfacial Characterization and Performance Evaluation

Films of CoP have been electrochemically synthesized, characterized, and evaluated for performance as a catalyst for the hydrogen-evolution reaction (HER). The film was synthesized by cathodic deposition from a boric acid solution of Co2+ and H2PO2– on copper substrates followed by operando remediation of exogenous contaminants. The films were characterized structurally and compositionally by scanning-electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Raman spectrophotometry. The catalytic activity was evaluated by cyclic voltammetry and chronopotentiometry. Surface characterization prior to electrocatalysis indicated that the film consisted of micrometer-sized spherical clusters located randomly and loosely on a slightly roughened surface. The composition of both the clusters and surface consisted of cobalt in the metallic, phosphide, and amorphous-oxide forms (CoO·Co2O3) and of phosphorus as phosphide and orthophosphate. The orthophosphate species, produced .
Degenerate Si as an Electrode Material for Electrochemical Biosensors

The use of degenerate (heavily doped) Si as an electrode material for electrochemical biosensors is demonstrated by a series of voltammetry and impedance studies. Cyclic voltammetry in solutions of NH 4 F and K 3 Fe(CN) 6 /K 4 Fe(CN) 6 exhibits reversible electrochemistry without illumination, which to the best of the authors' knowledge has not been previously reported for Si electrodes in an aqueous environment. The presence of F - prevents formation of the Si native oxide, while the use of a degenerate Si substrate makes its electrochemistry more like that of a metal. In addition, impedance detection of peanut protein Ara h 1 is demonstrated on a degenerate Si electrode following immobilization of the monoclonal mouse antibody to this protein. The variation in charge-transfer resistance with protein concentration is employed to estimate the dissociation constant of the surface-immobilized antibody-antigen complex as 0.25 nM. The advantages of degenerate Si relative to n- and p-type Si include the lack of photoeffects, a simpler equivalent circuit, easier electrical connection to the working electrode, and knowledge that the applied potential applied is dropped within the electrical double layer, not within the semiconductor space-charge layer. Most important, degenerate Si electrodes are easily incorporated into Si-based semiconductor devices.
Synthesis and Application Research of op-10/ Cationic Surfactant Composite Asphalt Emulsifier

In this paper, the non-ionic intermediate was prepared by op-10 and epoxy chloropropane; the quaternary ammonium salt intermediate was prepared by triethylamine and epoxy chloropropane; the op-10/cationic surfactant composite asphalt emulsifier was synthesized by reacting with non-ionic intermediate, quaternary ammonium salt intermediate and N-octadecyl propylene diamine. The effect of synthesis conditions and the prescription on the emulsifying property, surface activity and using performance of emulsifier was studied, a new way for the preparation of the composite asphalt emulsifier was explored.
Synthesis and characterization of novel optically active and flame-retardant heterocyclic polyimides

Tetrachlorophthalic anhydride (1) was reacted with L-leucine (2) in toluene solution at refluxing temperature in the presence of triethylamine and the resulting imide-acid (4) was obtained in quantitative yield. The compound (4) was converted to the N-(tetrachlorophthaloyl)-L-leucine acid chloride (5) by reaction with thionyl chloride. The reaction of this acid chloride (5) with isoeugenol (6) was carried out in chloroform and novel optically active isoeugenol ester derivative (7) as a chiral monomer was obtained in high yield. The compound (7) was characterized by 1H-NMR, IR, Mass and elemental analysis, and then was used for the preparation of model compound (10) and polymerization reactions. 4-Phenyl-1,2,4-triazoline-3,5-dione, PhTD (8) was allowed to react with compound (7). The reaction is very fast, and gives only one diastereomer of (10) via Diels–Alder and ene pathways in excellent yield. The polymerization reactions of novel monomer (7) with bistriazolinediones [bis-(p-3,5-dioxo-1,2,4-triazolin-4-ylphenyl)methane (11) and 1,6-bis-(3,5-dioxo-1,2,4-triazolin-4-yl)hexane] (12) were carried out in N,N-dimethylacetamide (DMAc) at room temperature. The reactions are exothermic, fast, and give novel optically active polymers (13) and (14) via repetitive Diels–Alder-ene polyaddition reactions. The resulting polymers are optically active, thermally stable, and flame resistant. All of the above compounds were fully characterized by IR, 1H-NMR, elemental analysis, and specific rotation. Some structural characterization and physical properties of these novel heterocyclic polyimides are reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 240–248, 2000