Miracle-dz/UniFAR-FTUs huggingface dataset:
Influence of Solid Fraction on the Optimum Molecular Weight of Polymer Dispersants in Aqueous TiO2 Nanoparticle Suspensions

The effects of solid fraction and molecular weight of a polymer dispersant¯sodium polyacrylate-on the apparent viscosity of an aqueous TiO 2 nanoparticle suspension were investigated by varying the particle solid fractions from 15 to 37 vol% and the molecular weight of the dispersant from 1200 to 30000. When the solid fraction was increased, the molecular weight of the dispersant was decreased to obtain the lowest suspension viscosity. The effect of the molecular weight of the dispersant on the suspension viscosity was discussed based on the surface interaction between TiO 2 particles characterized by a colloid probe atomic force microscope. The polymer dispersant adsorbed on a particle surface enhanced the repulsive force between the TiO 2 particles and reduced adhesion by electrosteric interaction, which reduced the suspension viscosity. The size of the dispersant in the aqueous solution determined by a dynamic light scattering method was compared with the estimated particle surface distance. As the solid fraction increased, the average surface distance and the size of the dispersant attainable to the particle surface reduced; therefore, the optimum molecular weight of the dispersant for a dense suspension is also reduced.
Response of wheat to foliar phosphorus treatments under field and high temperature regimes

Abstract Potassium phosphate (KH2PO4) is applied commonly in dilute foliar sprays to wheat (Triticum aestivum L.) in China. Yield responses to foliar P sources have also been reported for several crop species in other countries. Experiments were conducted to determine efficacy of four P sources and four rates of KH2PO4 as foliar treatments on wheat under field conditions and KH2PO4 under two controlled temperature regimes. Grain yields were increased most by KH2PO4 followed by β‐glycerophosphate and tripolyphosphate; only phytic acid was ineffective. All rates of 1 to 4 kg ha‐1 KH2PO4 increased grain yields. Foliar KH2PO4 applications increased grain weight early under low controlled temperatures, but did not affect final grain weight under either temperature regime. Beneficial effects of foliar P treatments were associated with increased plant P content, which may have increased cell sugar content and protected membranes. Although preliminary results are favorable, additional research is needed to determ.
Molecular dynamics simulations of a fully hydrated dimyristoylphosphatidylcholine membrane in liquid-crystalline phase

Molecular dynamics (MD) simulations were performed to investigate the structure of a fully hydrated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayer in liquid-crystalline (fluid) phase at 30 °C. The bilayer consists of 200 DMPC lipid molecules with nw=27.4 water molecules per lipid. The membrane was built with reference to the coordinates of a previously published 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane patch. A four-step dynamic procedure (110 ps) with Berendsen pressure rescaling (P=0 and 1 bar), applied in all three directions, was used to rapidly prepare the bilayer. This system was then subjected to two separate constant pressure and temperature simulations at 1 bar and 30 °C for ∼380 ps, using the Nose–Hoover NPT method with periodical boundaries and Berendsen temperature and pressure rescaling method, respectively. The resultant bilayer has an area per lipid of 59.2 A2 and a head-to-head thickness (DHH) of 36.3 A. These values are in good agreement with the x-ray .
Monte-Carlo Simulations of Centrifugal Gas Separation

The use of a Monte–Carlo formalism in a centrifugal gas process separation simulation provides an efficient predictor of dew-pointing as a function of the imposed radial pressure gradient. Previously, this was done by simply calculating radial pressure and then resorting to a separate equation of state routine for evaluating whether condensation will occur or not. In our model, we incorporate the potential energy associated with rotation of a gas element into the simulation along with molecular interaction terms. This enables us to predict when sufficient nucleation has occurred that condensed material forms—an important limit for stable operation of a gas centrifuge.
Predicting Impact Sensitivity of Heterocyclic Nitroarenes from Molecular Structures Selected by Genetic Algorithm

A novel theoretical model was constructed to predict the impact sensitivity of 44 heterocyclic nitroarenes. The optimal subset of the molecular structures descriptors were selected by genetic algorithm (GA). The multiple linear regression (MLR) was then applied to build a prediction model of impact sensitivity for the 44 compounds. The correlation coefficients (R2) together with correlation coefficient of the leave-one-out cross validation (Q2CV) of the model is 0.928 and 0.865, respectively. The new model is highly statistically significant, and the robustness as well as internal prediction capability of which is satisfactory. The predicted impact sensitivity values are in good agreement with the experimental data.
J coupling in chemically equivalent spin pairs as studied by solid‐state nuclear magnetic resonance

The presence of J coupling was observed in the solid‐state nuclear magnetic resonance (NMR) spectrum of the 31P spin pair in polycrystalline 1,2‐bis (2,4,6‐tri‐tert‐butylphenyl)‐diphosphene (TBPDP) using the magic‐angle spinning (MAS) technique. This represents the first example of J coupling in a spin‐pair system with nuclei having identical isotropic chemical shifts. Average Hamiltonian theory is used to derive the time‐independent eigenstates for the system. It is shown that a second‐order perturbation term, which is dependent on the difference between the chemical‐shift tensor orientations in addition to the strength of the dipolar coupling, allows the recoupling of the J interaction for the two chemically equivalent 31P nuclei. In the absence of the perturbation term, the system is reduced to an A2 case in solution‐state NMR for which, of course, no J coupling may be observed. The magnitude of the J coupling, namely, 580±20 Hz obtained from two‐dimensional (2D) J‐resolved experiments was found to be .
A novel, wave-like, two-dimensional anionic host with Cationic and neutral guests: crystal structure of [C6H11NH3][Cu2(CN)3] · 2C6H5NH2

A novel inclusion compound, [C6H11NH3][Cu2(CN)3] · 2C6H5NH2, has been synthesized and structurally characterized by X-ray crystallographic methods. It crystallizes in the monoclinic space group P21/n with a = 8.839(1), b = 18.894(2), c = 14.080(3) Å, β = 93.76(1)°, V = 2346.5(7) Å3, Z = 4. The structure is composed of the anionic layered two-dimensional host [Cu2(CN)3]− and the cationic onium guest [C6H11NH3]+ and neutral guests, C6H5NH2. Each Cu(I) atom is bonded to three cyanide ligands and exhibits trigonal coordination. Cu(I)–CN–Cu(I) bridges from puckered hexagons with all edges shared. The cyclohexylammonium and aniline guests are situated between host layer sheets. The cyclohexylammonium ion has a chair conformation and lies perpendicular to the host layer. The aniline molecules are arranged perpendicular and inclined at approximately 45° to the host layer, respectively. Both guest molecules are held together by a network of hydrogen bonds.
Nanomechanical properties of supported lipid bilayers studied by force spectroscopy

The physicochemical properties of biological membranes are crucial to understand membrane function, since their main role is to provide a barrier that divides electrolytic solutions into different compartments guaranteeing at the same time membrane mechanical stability. It is well-known that the chemical composition of the phospholipid molecules that compose the membrane greatly determine the architecture of such biological systems. Force Spectroscopy with AFM is a powerful tool able to study the nanomechanical properties of supported planar bilayers (SPBs). Force plots on lipid bilayers show a discontinuity in the approaching curve that is interpreted as the penetration of the AFM tip through the lipid bilayer. The force at which this discontinuity occurs is the maximum force the bilayer is able to withstand before breaking and it can be regarded as a "fingerprint" of the bilayer stability, just like force is the fingerprint for a protein to unfold or for a hard material surface to be indented. We report on an experimental quantitative Force Spectroscopy study on how both lipid bilayer stability and compactness depend on the solution ionic composition.
A COMPARISON OF HPLC WITH FLUORESCENCE DETECTION AND FIXED WAVELENGTH FLUORESCENCE METHODS FOR THE DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBON METABOLITES IN FISH BILE

Fish exposed to polycyclic aromatic hydrocarbons (PAHs) accumulate only a small amount of PAH in their tissues. Hydrophobic PAHs are readily transformed into hydrophilic metabolites and excreted in bile. Bile samples of five fish species were collected from the Baltic Sea and analyzed using two methods: high-performance liquid chromatography (HPLC) with fluorescence detection and a fixed wavelength fluorescence method. With the HPLC method PAH compounds were quantitated after hydrolysis, and with the fluorescence method without enzyme-assisted hydrolysis. In HPLC analysis the major metabolite in all fish species, 1-hydroxypyrene, was the only metabolite detected in perch and salmon samples. 1-Hydroxyphenanthrene was detected in a few flounder and in most eelpouts. The correlation between the two methods for pyrene-type metabolites was good (r2 = 0.773).
Micro-pellet method for infrared absorption spectroscopy using a diamond anvil cell under a quasi-hydrostatic condition

A method was proposed for measuring infrared absorption spectra at high pressure under quasi-hydrostatic pressure conditions. Two KBr micro-pellets were prepared as samples, and reference materials were charged in a diamond anvil cell, applying helium as the pressure-transmitting medium. Using this method, the quasi-hydrostatic pressure condition was retained up to approximately 20 GPa. Furthermore, hydrostaticity was much better than conventional pressure-transmitting media used for infrared spectroscopy. Infrared absorption spectra of α -FeOOH at high pressure were measured using the KBr micro-pellet method with a helium pressure-transmitting medium. Downshift of the OH stretching vibration was observed with increasing pressure. Use of the KBr micro-pellet method for infrared absorption spectroscopy at high pressure is a complementary experimental technique to neutron diffraction at high pressure for studying the pressure response of hydrogen bonds.
Interactions of Agonists with Platelet α2-Adrenergic Receptors

Epinephrine induces human platelet aggregation by interacting with α-adrenergic receptors. These sites were demonstrated by radioligand-binding techniques using the new antagonist ligand, [3H]yohimbine. The sites labeled by [3H]yohimbine had the specificity of α2-receptors with the affinity of yohimbine » prazosin. Epinephrine-mediated inhibition of prostaglandin E1-stimulated adenylate cyclase activity in human platelet lysates was also found to have an α2-receptor specificity. Competition curves of antagonists with [3H]yohimbine indicated a homogeneous population of α2-receptors. In contrast, competition curves of a series of full and partial agonists with [3H] yohimbine were resolved into two distinct affinity states; the ratio of the dissociation constants of agonists for the low and high affinity states was positively correlated with the agonist's intrinsic activity for inhibition of adenylate cyclase. Guanine nucleotides were found to destabilize the high affinity form of the a 2-receptors. At high .
Antioxidant properties of some medicinal Aristolochiaceae species

Antioxidant properties of five Aristolochiaceae species namely Aristolochia brasiliensis Mart. and Zucc. , Aristolochia bracteolata Retz. , Aristolochia indica Linn. , Apama siliquosa Lamk. and Aristolochia tagala Cham. were investigated. Antioxidant and 2,2-diphenyl picrylhydrazyl (DPPH) radical scavenging activities, reducing powers, and the amount of total phenolic compounds of the extracts were studied. The highest antioxidant activity was shown by A. tagala and the lowest one was A. brasiliensis. The highest DPPH radical scavenging activity was shown by A. tagala and the least one was shown by A. brasiliensis. The highest reducing power and amount of total phenolic compounds was shown by A. tagala and lowest one was A. brasiliensis.
Narrowly dispersed imprinted microspheres with hydrophilic polymer brushes for the selective removal of sulfamethazine

In this work, a facile and general protocol to synthesize molecularly imprinted microspheres (MIMs), combining reverse atom transfer radical polymerization with precipitation polymerization, is described. Well-tuned surface properties in the as-obtained microspheres were achieved through the “living” nature of the active ATRP-initiators present on the surface in order to further functionalize the microspheres with hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) brushes. The presence of a PHEMA shell on the MIMs was confirmed by SEM, FT-IR and water contact angle studies, and some quantitative information is also provided. Batch adsorption experiments were carried out in pure water to investigate the equilibrium, kinetics and selectivity properties of the imprinted materials. The adsorption data of the ungrafted imprinted materials for sulfamethazine (SMZ) were fitted well to the Freundlich isotherm model. However, after grafting, the Langmuir isotherm fits the data better, mainly because of the changes to the surface properties that increase the hydrophilicity and suppress the hydrophobically driven non-specific interactions. The imprinted microspheres exhibit a large adsorption capacity, and are also specific to SMZ but non-specific to other antibiotics. The obtained materials also show rapid kinetics and great reusability and stability, displaying potential for practical applications for the selective removal of pollutants from aqueous environments.
Synthesis, Physicochemical Properties, and Conformational Studies of (3-Alkoxymethyl-4-hydroxyphenyl)ethanones

A homologous series of (3-alkoxymethyl-4-hydroxyphenyl)ethanones was prepared by the reaction of (3-chloromethyl-4-hydroxyphenyl)ethanone with the different alcohols in the presence of sodium hydrogen carbonate. The confirmation of structures was achieved by interpretation of IR, UV, and 1H NMR spectra. Molecular modeling methods were used to establish conformations with global and local energetic minima. It was found that energetically the most stable conformations involved hydrogen bond formation between the hydrogen of phenolic group and the oxygen of alkoxyl group. Enthalpy values of hydrogen bonds of selected compounds were 24.86—30.51 kJ mol−1 and their distances were in the range 0.282—0.293 nm.
Thickness measurements of wet protein crystals in the electron microscope

With the stable environment afforded by a dynamically pumped wet specimen chamber, the thickness of a fully hydrated protein microcrystal may be obtained in an electron microscope from an incident-beam attenuation measurement after disappearance of the diffraction pattern. Such measurements on orthorhombic catalase crystals have been successfully cross-correlated with thickness measurements on the same crystals made with an interference light microscope over a range from a few hundred to a few thousand Angstroms.
Rietveld analysis of mechanically activated BaCO3–TiO2 system

BaTiO3 powders were prepared through mechanical activation chemistry and analyzed by Rietveld refinement with X-ray diffraction data. Raw BaCO3 and TiO2 powders were dry milled for 5 and 20 h and then calcinated for 2 and 4 h at 800 °C. The milling process was found to have broken up the BaCO3 and TiO2 crystals into smaller crystals and formed only small amounts (<1.5 wt%) of BaTiO3. Subsequence calcinations for 2 and 4 h at 800 °C successfully produced large amounts (>97.7 wt%) of BaTiO3 crystals. The calcination process also generated microstrains and crystallite-size anisotropy in BaTiO3. An increase in the calcination time from 2 to 4 h increased the BaTiO3 weight percentage and the crystallite-shape anisotropy, but decreased the tetragonal distortion anisotropic microstrains in BaTiO3 crystals.
Cyclohexane Diamine Tetraacetic Acid (CDTA) Extraction of Plant Cell Wall Pectin

[Abstract] The goal of this procedure is to extract pectin from plant cell walls. Pectins are galacturonic acid containing polymeric sugars that are important components of plant cell walls. Various procedures aimed at studying plant cell wall components require the extraction of pectin. Pectin is synthesized in the Golgi apparatus in a highly esterified fashion and is de-esterified in the cell wall (Mohnen, 2008). Pectin is generally water soluble. De-esterified pectin can form socalled “egg-box structures” in the presence of Ca 2+ ions (Mohnen, 2008; Harholt et al., 2010). Pectin in these “egg-box structures” is cross-linked and less soluble. Cyclohexane diamine tetraacetic acid (CDTA) chelates Ca 2+ ions and hence allows extraction of Ca 2+ cross-linked pectin from cell walls.
The kinetic ordering and growth dissymmetrisation in crystalline solid solutions

The review concerns the order–disorder kinetic (growth) phase transitions, which are characteristic of inorganic crystalline solid solutions. The emphasis is placed on the emergence of metastable low-symmetry phases (i.e., the dissymmetrisation of crystals), which can occur due to the drastic difference between the atomic structures of growing faces and the bulk crystal. The experimental techniques for the elucidation of this phenomenon, possible crystal symmetries and structures induced by the dissymmetrisation as well as the effects of crystal composition, growth medium composition, growth temperature and growth rate are analysed.
Absolute rate constants for hydrocarbon autoxidation. VI. Alkyl aromatic and olefinic hydrocarbons

Absolute rate constants have been measured for the autoxidation of a large number of hydrocarbons at 30 °C. The chain-propagating and chain-terminating rate constants depend on the structure of the hydrocarbon and also on the structure of the chain-carrying peroxy radical. With certain notable exceptions which are mainly due to steric hindrance, the rate constants for hydrogen-atom abstraction increase in the order primary < secondary < tertiary; and, for compounds losing a secondary hydrogen atom, the rate constants increase in the order unactivated < acyclic activated by a single π-electron system < cyclic activated by a single Π-system < acyclic activated by two π-systems < cyclic activated by two π-systems. The rate constants for chain termination by the self-reaction of two peroxy radicals generally increase in the order tertiary peroxy radicals < acyclic allylic secondary cyclic secondary acyclic benzylic secondary < primary peroxy radicals < hydroperoxy radicals.
Numerical Simulation of Supercritical Water Heat Transfer in the Vertically Heated Tube

The heat transfer of water in a vertically heated tube at 24.52 MPa is numerically simulated by computational fluid dynamics software of FLUENT. The IAPWS-IF97 formulation is applied to obtain the water properties, which vary substantially at supercritical condition. The two-dimensional axi-symmetric model using RNG k-e turbulence model with enhanced wall treatment gives fine prediction of wall temperature and heat transfer coefficient. The mesh size near the wall adapted smaller when at high heat fluxes for the accuracy of computed results. The wall heat fluxes were set to be 233, 698, 930 and 1100 kW/m2 to match the simulation with experiment performed by Yamagata. It is found that k-e turbulence model with enhanced wall treatment can give outstanding prediction of heat transfer enhancement and heat transfer deterioration. The heat transfer coefficient value reaches a maximum near the pseudocritical point and it decreases with increase of heat flux. © 2013 ASME
Spacer Length Effect on the Photoinduced Electron Transfer Fluorescent Probe for Alkali Metal Ions

Abstract— We have synthesized four derivatives of aikyi pyrene covalently bonded to aza‐lS‐crown‐6 at the nitrogen position, Py(CH2)n, (n = 1–4), to study the effect of spacer length on the emission properties of pyrene fluorophore upon complication of alkali metal ions by the crown moiety. In the absence of alkali metal ions, the parent molecule is weakly fluorescent because its emission is partially quenched by photoinduced electron transfer (PET) from nitrogen lone pairs to the excited singlet state of pyrene. Complication of alkali metal ions (e.g. K+) by the crown moiety prevents the nitrogen lone pair from participating in PET and results in an enhancement in the observed emission from pyrene (fluorescent turn on). Because the PET effect could be exerted through bonds as well as space, its magnitude may show a dependence on chain length. We have examined the fluorescence behavior of these pyrene aza‐crown ether derivatives in the presence of alkali metal ions to determine the magnitude of such an effect and its impact on the sensitivity of the fluorescent probe for detection purposes. Our results indicate that maximum efficiency for PET between the pyrene moiety and aza‐crown ether is achieved when n ≤ 3.
A Rapid and Highly Selective Resonance Scattering Spectral Assay for Trace Carcinoembryonic Antigen

Gold nanoparticles, in size of 10 nm, were used to label monoclonal carcinoembryonic antigen antibody (CEAAb) to obtain an immunonanogold resonance scattering (RS) spectral probe (AuCEAAb) for the measurement of trace carcinoembryonic antigen (CEA). In pH 6.8 Na2HPO4-NaH2PO4 buffer solution and the presence of polyethylene glycol (PEG)-6000, the AuCEAAb combined with CEA to form the nanogold-labeled immunocomplex clusters in average size of 227 nm, which exhibited two scattering peaks at about 320 and 581 nm. The enhanced RS intensity at 581 nm (ΔI581 nm) is proportional to CEA concentration in the range of 1.0–50.0 ng/mL, with a detection limit (DL) of 0.52 ng/mL. The immunonanogold RS assay was utilized to determine CEA in serum samples with high sensitivity, good selectivity and simplicity.
Mechanism of Asymmetric Hydrogenation Catalyzed by a Rhodium Complex of (S,S)-1,2-Bis(tert-butylmethylphosphino)ethane. Dihydride Mechanism of Asymmetric Hydrogenation

The mechanism of asymmetric hydrogenation catalyzed by a new effective catalyst, viz., a rhodium complex of (S,S)-1,2-bis(tert-butylmethylphosphino)ethane (BisP*), has been studied by multinuclear NMR. Hydrogenation of the precatalyst [Rh(BisP*)(nbd)]BF4 (8) at −20 °C in deuteriomethanol affords solvate complex [Rh(BisP*)(CD3OD)2]BF4 (9), which is, in turn, hydrogenated at −90 °C producing equilibrium amounts (20% at −95 °C) of [RhH2(BisP*)(CD3OD)2] (10)the first observable dihydride of a Rh(I) complex with a diphosphine ligand. Dihydride 10 is in equilibrium with 9 and dihydrogen, which was studied in the temperature interval from −100 to −50 °C, yielding thermodynamic parameters ΔH = −6.3 ± 0.2 kcal M-1 and ΔS = −23.7 ± 0.7 cal M-1 K-1. The hydrogenation of 9 is stereoselective: two isomers 10a and 10b are produced in a ratio 10:1. Use of HD for the hydrogenation of 9 yields the isomers with deuterium cis and trans to the phosphine in a ratio 1.3 (±0.1):1. The thermodynamic parameters of the equilibriu.